Catheter and ablation catheter

Abstract

An ablation catheter (1) having: a shaft (2) having a longitudinal direction (x); a proximal basket (21) having an electrode (11) and disposed on a distal portion of the shaft (2); and a distal basket (41) having an electrode (31) and disposed so as to overlap part of the proximal basket (21) in the longitudinal direction (x).

Description

Catheter and Ablation Catheter

[0001] The present disclosure relates to a catheter and an ablation catheter.

[0002] In the examination and treatment of arrhythmias such as atrial fibrillation, a catheter provided with electrodes is used. During the examination, by inserting the catheter into the heart cavity, the intracardiac potential is measured to identify the abnormal site of the heart that causes the arrhythmia. During treatment, radiofrequency ablation, pulsed-field ablation, etc. are performed. In radiofrequency ablation, a high-frequency current is passed from the electrode to the myocardium that causes the arrhythmia, and the origin of the arrhythmia is electrically separated from the heart by cauterizing it. Pulsed-field ablation uses the phenomenon that when tissue is exposed to an electric field formed by applying a pulsed voltage between electrodes, the cell membrane is perforated and cell death is caused, enabling selective ablation.

[0003] Patent Document 1 discloses an electrophysiology (EP) catheter for cardiac mapping and / or ablation. This catheter has a basket-shaped electrode assembly at the distal end of a catheter body formed from a plurality of spines having electrodes. Each spine can be deflected outward into a configuration in which the electrode assembly has a proximal basket region and a distal basket region having different equatorial diameters.

[0004] Japanese Patent Application Laid-Open No. 2017-29727

[0005] The catheter described in Patent Document 1 had room for improvement from the perspective of improving the efficiency of the procedure. Therefore, the present disclosure aims to solve the problem of providing a catheter that contributes to improving the efficiency of the procedure.

[0006] The catheter according to the first embodiment of the present disclosure that has solved the above problems is as follows. [1] A shaft having a longitudinal direction, A proximal basket having electrodes and disposed at the distal portion of the shaft, A distal basket having electrodes and disposed overlapping a part of the proximal basket in the longitudinal direction. An ablation catheter having.

[0007] Furthermore, the catheter according to the first embodiment is preferably any of the following [2] to

[12] . [2] The ablation catheter according to [1], wherein in the longitudinal direction, the distal end of the proximal basket is located between the proximal end of the distal basket and the position of the maximum outer diameter of the distal basket. [3] The ablation catheter according to [1] or [2], wherein in the longitudinal direction, the proximal end of the distal basket is located between the position of the maximum outer diameter of the proximal basket and the distal end of the proximal basket. [4] The ablation catheter according to [1] or [2], wherein in the longitudinal direction, the proximal end of the distal basket is in the same position as the proximal end of the proximal basket. [5] The ablation catheter according to any one of [1] to [4], wherein, in the longitudinal direction, the length of the first portion in which the distal basket and the proximal basket overlap is longer than the length of the second portion of the proximal basket that does not overlap with the distal basket, when both the distal basket and the proximal basket are in their most expanded state. [6] The ablation catheter according to any one of [1] to [5], wherein the shaft has a lumen extending in the longitudinal direction, and the ablation catheter further comprises: a traction member extending in the longitudinal direction, connected to at least one of the proximal basket and the distal basket, inserted into the lumen of the shaft and movable in the longitudinal direction relative to the shaft; a first connection portion connecting the distal end of the traction member to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member; a second connection portion connecting the proximal end of the distal basket to the cylindrical member; a third connection portion connecting the distal end of the proximal basket to the cylindrical member; and a fourth connection portion connecting the proximal end of the proximal basket to the distal end of the shaft.[7] The ablation catheter according to any one of [1] to [5], wherein the shaft has a lumen extending in the longitudinal direction, and the ablation catheter further comprises: a traction member extending in the longitudinal direction, connected to at least one of the proximal basket and the distal basket, inserted into the lumen of the shaft and movable in the longitudinal direction relative to the shaft; a first connection portion connecting the distal end of the traction member and the distal end of the distal basket; and a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member, wherein the distal end of the proximal basket is connected to the cylindrical member, and the proximal end of the distal basket is connected to the distal end of the shaft. [8] The ablation catheter according to any one of [1] to [5], wherein the shaft has a lumen extending in the longitudinal direction, and the ablation catheter further comprises a traction member extending in the longitudinal direction, connected to at least one of the proximal basket and the distal basket, inserted into the lumen of the shaft and movable in the longitudinal direction relative to the shaft, and a first connection portion connecting the distal end of the traction member to the distal end of the distal basket, wherein the distal end of the proximal basket is connected to the middle of the longitudinal direction of the traction member, and the proximal end of the distal basket is connected to the distal end of the shaft. [9] The ablation catheter according to any one of [1] to [8], wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and when the ablation catheter is viewed from the distal side toward the proximal side, the first wires and the second wires are arranged alternately in the circumferential direction.

[10] The ablation catheter according to [9], wherein the first wire and the second wire are separated when both the distal basket and the proximal basket are in their most expanded state.

[11] The ablation catheter according to any one of [1] to

[10] , wherein both the electrode of the proximal basket and the electrode of the distal basket are electrodes for ablation.

[12] The ablation catheter according to any one of [1] to

[11] , wherein, when both the distal basket and the proximal basket are fully expanded, the maximum outer diameter of the proximal basket is greater than the maximum outer diameter of the distal basket.

[0008] A catheter according to a second embodiment of the present disclosure that can solve the above problems is as follows:

[13] An ablation catheter having a shaft having a longitudinal direction; a proximal basket having a first electrode for performing either ablation or potential measurement and disposed at the distal part of the shaft; and a distal basket having a second electrode for performing either ablation or potential measurement and disposed at least a part of the longitudinal direction distal to the proximal basket.

[0009] Furthermore, the catheter according to the second embodiment is preferably any of the following

[14] to

[23] .

[14] The ablation catheter according to

[13] , wherein in the longitudinal direction, the distal end of the proximal basket is located proximal to the proximal end of the distal basket.

[15] The ablation catheter according to

[13] or

[14] , wherein the first electrode is an electrode for cauterization, and the proximal basket does not have an electrode for measuring potential.

[16] The ablation catheter according to any one of

[13] to

[15] , wherein the second electrode is an electrode for measuring potential, and the distal basket does not have an electrode for cauterization.

[17] The ablation catheter according to

[13] or

[14] , wherein the second electrode is an electrode for cauterization, and the distal basket does not have an electrode for measuring potential.

[18] The ablation catheter according to any one of

[13] ,

[14] , or

[17] , wherein the first electrode is an electrode for measuring potential, and the proximal basket does not have an electrode for cauterization.

[19] The ablation catheter according to any one of

[13] to

[18] , wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and when the ablation catheter is viewed from the distal side toward the proximal side, the first wires and the second wires are arranged alternately in the circumferential direction.

[20] The ablation catheter according to any one of

[13] to

[19] , wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and when the ablation catheter is viewed from the distal side toward the proximal side, the first wires and the second wires are arranged to overlap.

[21] The ablation catheter according to any one of

[13] to

[20] , wherein when both the distal basket and the proximal basket are in their most expanded state, the maximum outer diameter of the proximal basket is greater than the maximum outer diameter of the distal basket.

[22] The ablation catheter according to any one of

[13] to

[21] , wherein the distal basket and the proximal basket are each independently expandable.

[23] The ablation catheter according to any one of

[13] to

[22] , further comprising a traction member extending longitudinally and connected to at least one of the proximal basket and the distal basket, and movable longitudinally relative to the shaft, wherein the shaft has a lumen extending longitudinally, the traction member is inserted through the lumen of the shaft, and the proximal basket and the distal basket expand as the traction member moves proximal to the shaft.

[0010] A catheter according to a third embodiment of the present disclosure that can solve the above problems is as follows:

[24] A catheter comprising: a shaft having a longitudinal direction; a proximal basket disposed at the distal end of the shaft; and a distal basket whose longitudinal direction at least a portion is disposed distal to the proximal basket, wherein at least one of the proximal basket and the distal basket has an electrode, and the expandable portion takes a first state in which both the distal basket and the proximal basket are contracted, and a second state in which the distal basket is expanded and the proximal basket is contracted.

[0011] Furthermore, a catheter according to a third embodiment is preferably any of the following

[25] to

[35] .

[25] The catheter according to

[24] , wherein the catheter further has a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, the shaft has a lumen that extends in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the expanded portion transitions from the first state to the second state by moving the traction member proximal to the shaft.

[26] The catheter according to

[24] or

[25] , wherein the expanded portion takes a third state in which both the distal basket and the proximal basket are expanded.

[27] The catheter according to

[26] , wherein the catheter further comprises a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, the shaft having a lumen that extends in the longitudinal direction, the traction member being inserted into the lumen of the shaft, and the expansion portion transitions in the order of the first state, the second state and the third state by moving the traction member proximal to the shaft.

[28] The catheter according to

[25] or

[27] , further comprising: a first connection portion to which the distal end of the traction member is connected to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member; a second connection portion to which the proximal end of the distal basket is connected to the cylindrical member; a third connection portion to which the distal end of the proximal basket is connected to the cylindrical member; and a fourth connection portion to which the proximal end of the proximal basket is connected to the distal end of the shaft.

[29] The catheter according to

[28] , wherein in the longitudinal direction, the second connection portion is located proximal to the third connection portion.

[30] The catheter according to

[28] , wherein in the longitudinal direction, the second connection is located distal to the third connection.

[31] The catheter according to

[25] or

[27] , wherein the catheter further comprises: a first connection to which the distal end of the traction member is connected to the distal end of the distal basket; and a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member, wherein the distal end of the proximal basket is connected to the cylindrical member, and the proximal end of the distal basket is connected to the distal end of the shaft.

[32] The catheter according to

[25] or

[27] , wherein the traction member comprises an outer member having a cylindrical shape and an inner member disposed within the outer member and movable in the longitudinal direction relative to the outer member, the distal end of the proximal basket being connected to the distal end of the outer member, and the distal end of the distal basket being connected to the distal end of the inner member.

[33] The catheter according to any one of

[24] to

[32] , wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and the bending stiffness of the second wires is lower than that of the first wires.

[34] The catheter according to

[33] , wherein the Young's modulus of the second wires is smaller than that of the first wires.

[35] The catheter according to any one of the claims

[24] to

[34] , wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and in the first state, the second wires are longer than the first wires in the longitudinal direction of the shaft.

[0012] A catheter according to a fourth embodiment of the present disclosure that can solve the above problems is as follows:

[36] A catheter comprising: a shaft having a longitudinal direction; a proximal basket disposed at the distal end of the shaft; and a distal basket, at least a portion of which is disposed distal to the proximal basket in the longitudinal direction, wherein at least one of the proximal basket and the distal basket has an electrode, and the expandable portion takes a first state in which both the distal basket and the proximal basket are contracted, and a second state in which the proximal basket is expanded and the distal basket is contracted.

[0013] Furthermore, the catheter according to the fourth embodiment is preferably any of the following

[37] to

[47] .

[37] The catheter according to

[36] , wherein the catheter further has a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, the shaft has a lumen that extends in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the expanded portion transitions from the first state to the second state when the traction member moves proximal to the shaft.

[38] The catheter according to

[36] or

[37] , wherein the expanded portion takes a third state in which both the distal basket and the proximal basket are expanded.

[39] The catheter according to

[38] , wherein the catheter further comprises a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, the shaft having a lumen that extends in the longitudinal direction, the traction member being inserted through the lumen of the shaft, and the expansion portion transitions in the order of the first state, the second state and the third state by moving the traction member proximal to the shaft.

[40] The catheter according to

[37] or

[39] , further comprising: a first connection portion connecting the distal end of the traction member to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member; a second connection portion connecting the proximal end of the distal basket to the cylindrical member; a third connection portion connecting the distal end of the proximal basket to the cylindrical member; and a fourth connection portion connecting the proximal end of the proximal basket to the distal end of the shaft.

[41] The catheter according to

[40] , wherein in the longitudinal direction, the second connection portion is located proximal to the third connection portion.

[42] The catheter according to

[40] , wherein in the longitudinal direction, the second connection portion is located distal to the third connection portion.

[43] The catheter according to

[37] or

[39] , wherein the catheter further comprises: a first connection portion to which the distal end of the traction member is connected to the distal end of the distal basket; and a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member, wherein the distal end of the proximal basket is connected to the cylindrical member, and the proximal end of the distal basket is connected to the distal end of the shaft.

[44] The catheter according to

[37] or

[39] , wherein the traction member comprises an outer member having a cylindrical shape and an inner member disposed within the outer member and movable in the longitudinal direction relative to the outer member, the distal end of the proximal basket being connected to the distal end of the outer member, and the distal end of the distal basket being connected to the distal end of the inner member.

[45] The catheter according to any one of

[36] to

[44] , wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and the bending stiffness of the first wires is lower than that of the second wires.

[46] The catheter according to

[45] , wherein the Young's modulus of the first wires is smaller than that of the second wires.

[47] The catheter according to any one of the claims

[36] to

[46] , wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and in the first state, the first wires are longer than the second wires in the longitudinal direction of the shaft.

[0014] In the ablation catheter according to the first embodiment, each basket can be assigned a different function. For example, one basket can be used to fix the catheter in the body or to measure potential, while the electrodes of the other basket can be used to perform ablation. Furthermore, in the above ablation catheter, the distance between the electrodes of multiple baskets can be brought closer together, so if both of these electrodes are used as ablation electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed more efficiently.

[0015] In the ablation catheter according to the second embodiment, when the first electrode of the proximal basket is for cauterization and the second electrode of the distal basket is for potential measurement, the procedure can be performed efficiently because the potential measurement is performed using the second electrode of the distal basket, which is introduced into the body first, and then cauterization can be performed with the first electrode of the proximal basket. Also, when the first electrode of the proximal basket is for potential measurement and the second electrode of the distal basket is for cauterization, the procedure can be performed efficiently because the potential measurement is performed with the first electrode on the front side and then cauterization can be performed with the second electrode on the back side.

[0016] According to the catheter of the third embodiment, the distal basket expands in the second state, causing it to come into contact with internal tissue. This allows the catheter to be fixed inside the body, making it easier to perform potential measurement and cauterization using electrodes.

[0017] According to the catheter of the fourth embodiment, the proximal basket expands in the second state, causing it to come into contact with internal tissue. This allows the catheter to be fixed inside the body, facilitating potential measurement and cauterization using electrodes.

[0018] Figure 3 is a side view of an ablation catheter according to the first embodiment of this disclosure, showing the proximal and distal baskets in a contracted state. Figure 4 is a side view of an ablation catheter according to the first embodiment of this disclosure, showing the proximal basket in an expanded state and the distal basket in a contracted state. Figure 5 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 4. Figure 5 is a cross-sectional view (partial side view) showing a modified version of the ablation catheter shown in Figure 4. Figure 4 is a cross-sectional view (partial side view) showing a modified version of the ablation catheter shown in Figure 4. Figure 5 is a cross-sectional view (partial side view) showing a modified version of the ablation catheter shown in Figure 4. Figure 8 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 4. Figure 4 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 4. This is a schematic diagram showing the arrangement of the first and second wires when viewed from distal to proximal in an ablation catheter according to the first embodiment of this disclosure. This is a schematic diagram showing a modified example of the ablation catheter according to the first embodiment of this disclosure, and shows the arrangement of the first and second wires when viewed from distal to proximal. This is a side view of an ablation catheter according to the second embodiment of this disclosure, showing the proximal and distal baskets in a contracted state. This is a side view of an ablation catheter according to the second embodiment of this disclosure, showing the proximal basket in an expanded state and the distal basket in a contracted state. This is a side view of an ablation catheter according to the second embodiment of this disclosure, showing the proximal and distal baskets in an expanded state. This is an enlarged side view of the distal side of the ablation catheter shown in Figure 16. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 17.This is a cross-sectional view (partial side view) showing a modified version of the ablation catheter shown in Figure 18. This is a side view showing a modified version of the ablation catheter shown in Figure 17. This is a side view showing a modified version of the ablation catheter shown in Figure 17. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 21. This is a side view showing a modified version of the ablation catheter shown in Figure 21. This is a side view showing another modified version of the ablation catheter shown in Figure 17. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 24. This is a side view showing another modified version of the ablation catheter shown in Figure 17. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the ablation catheter shown in Figure 26. This is a schematic diagram showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side of the ablation catheter according to the second embodiment of this disclosure. This is a schematic diagram showing a modified version of the ablation catheter according to the second embodiment of this disclosure, and is a schematic diagram showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side. Figure 32 is a side view of a catheter according to a third embodiment of this disclosure, showing the first state. Figure 33 is a side view of a catheter according to a third embodiment of this disclosure, showing the second state. Figure 34 is a side view of a modified version of the catheter shown in Figure 34. Figure 33 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 34. Figure 34 is a cross-sectional view (partial side view) showing a modified version of the catheter shown in Figure 34. Figure 33 is a side view showing a modified version of the catheter shown in Figure 34. Figure 37 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 37. Figure 37 is a side view showing a modified version of the catheter shown in Figure 34. Figure 37 is a side view showing another modified version of the catheter shown in Figure 34. Figure 40 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 40. Figure 33 is a cross-sectional view (partial side view) showing another modified version of the catheter shown in Figure 34.This is a schematic diagram showing the arrangement of the first and second wires when viewed from distal to proximal in a catheter according to the third embodiment of this disclosure. This is a schematic diagram showing a modified example of the catheter according to the third embodiment of this disclosure, and shows the arrangement of the first and second wires when viewed from distal to proximal. This is a side view of the catheter according to the fourth embodiment of this disclosure, showing the first state. This is a side view of the catheter according to the fourth embodiment of this disclosure, showing the second state. This is a side view of the catheter according to the fourth embodiment of this disclosure, showing the third state. This is an enlarged side view of the distal side of the catheter shown in Figure 47. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 48. This is a cross-sectional view (partial side view) showing a modified example of the catheter shown in Figure 49. This is a side view showing a modified example of the catheter shown in Figure 48. This is a side view showing a modified example of the catheter shown in Figure 48. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 52. This is a side view showing a modified example of the catheter shown in Figure 52. This is a side view showing another modified example of the catheter shown in Figure 48. This is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 55. This is a cross-sectional view (partial side view) showing another modified example of the catheter shown in Figure 48. This is a schematic diagram showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side of the catheter according to the fourth embodiment of this disclosure. This is a schematic diagram showing a modified example of the catheter according to the fourth embodiment of this disclosure, and is a schematic diagram showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side.

[0019] The contents of this disclosure will be described in more detail below based on the embodiments described below. However, the contents of this disclosure are not limited by the embodiments described below, and it is certainly possible to implement the disclosure with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of this disclosure. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of this disclosure.

[0020] The catheters according to each embodiment of this disclosure can be suitably used for the examination and treatment of arrhythmias such as atrial fibrillation. For example, they can be used for measuring, mapping, and ablation of intracardiac potentials. Ablation includes radiofrequency ablation and pulsed-field ablation.

[0021] It is preferable that each component of the catheter, particularly the component inserted into the body, be made of a biocompatible material.

[0022] The catheter according to the first embodiment is an ablation catheter. Hereinafter, in the description of the first embodiment, the ablation catheter may be simply referred to as a catheter. The catheter according to the first embodiment is characterized by having a longitudinal shaft, a proximal basket having an electrode and positioned at the distal end of the shaft, and a distal basket having an electrode and positioned overlapping a part of the proximal basket in the longitudinal direction. In the above catheter, different functions can be assigned to each basket. For example, one basket can be used to fix the catheter in the body or measure potential, and the electrode of the other basket can be used to perform cauterization. Furthermore, in the above catheter, it is easier to bring the distance between the electrodes of multiple baskets closer together, so if both of these electrodes are used as cauterization electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed efficiently.

[0023] A catheter according to the first embodiment of the present disclosure will be described with reference to Figures 1 to 13. Figures 1 to 3 are side views of a catheter according to the first embodiment of the present disclosure. Figure 1 shows the proximal basket and distal basket in a contracted state. Figure 2 shows the proximal basket in an expanded state and the distal basket in a contracted state. Figure 3 shows the proximal basket and distal basket in an expanded state. Figure 4 is an enlarged side view of the distal side of the catheter shown in Figure 3. Figure 5 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 4. Figure 6 is a cross-sectional view (partial side view) showing a modified example of the catheter shown in Figure 5. Figure 7 is a side view showing a modified example of the catheter shown in Figure 4. Figure 8 is a side view showing another modified example of the catheter shown in Figure 4. Figure 9 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 8. Figure 10 is a side view showing another modified example of the catheter shown in Figure 4. Figure 11 is a cross-sectional view (partially a side view) showing the connection state of each component on the distal side of the catheter shown in Figure 10. Figures 12 to 13 are schematic diagrams showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side of the catheter according to the first embodiment of this disclosure. Note that some wires are omitted in the diagrams showing the connection state of each component. As shown in Figures 1 to 5, the catheter 1 has a shaft 2, a proximal basket 21 having an electrode 11, and a distal basket 41 having an electrode 31.

[0024] As shown in Figures 1 to 3, the shaft 2 has a longitudinal direction x. As shown in Figure 5, the shaft 2 preferably has a distal end 2a and a proximal end 2b in the longitudinal direction x. The proximal side of the shaft 2 refers to the direction toward the user or operator's hand relative to the longitudinal direction x of the shaft 2, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. In each drawing, the right side of the figure is the proximal side, and the left side of the figure is the distal side. The shaft 2 preferably has a radial direction y and a circumferential direction z. The radial direction y refers to the radial direction of the shaft 2, in which the inward direction of the radial direction y refers to the direction toward the center of the longitudinal axis of the shaft 2, and outward direction of the radial direction y refers to the direction extending radially from the center of the longitudinal axis on the opposite side from the inward direction. The circumferential direction z refers to the direction around the longitudinal axis of the shaft 2, i.e., the direction along the outer circumference of the shaft 2.

[0025] The shaft 2 can be composed of one or more members. Examples of the shaft 2 include a resin tube, a metal tube, a hollow body formed by arranging wires in a predetermined pattern, a hollow body with at least one of its inner or outer surfaces coated with resin, or a combination thereof, for example, these connected in the longitudinal direction x. The resin tube can be manufactured, for example, by extrusion molding. Examples of hollow bodies with wires arranged in a predetermined pattern include cylindrical bodies having a mesh structure by simply crossing or weaving wires, and coils in which wires are wound. The wires may be one or more single wires or one or more stranded wires. The type of mesh structure is not particularly limited, nor are the number of turns or density of the coils. The mesh structure or coil may be formed at a constant density over the entire longitudinal direction x of the shaft 2, or it may be formed so that the density differs depending on the position in the longitudinal direction x. To increase the flexibility of the metal tube, notches or grooves may be formed on the outer surface of the metal tube. The shape of the cuts and grooves can be straight, arcuate, annular, spiral, or a combination of these.

[0026] The shaft 2 preferably has one or more lumens, and more preferably has only one. The shaft 2 is preferably a single-lumen tube.

[0027] The shaft 2 is preferably flexible and elastic. The material constituting the shaft 2 is preferably resin, metal, or a combination of resin and metal. Using resin makes it easier to impart flexibility and elasticity to the shaft 2. Using metal can improve the ease of insertion of the catheter 1 into the vascular lumen.

[0028] The shaft 2 may have a single-layer structure or a multi-layer structure. If the shaft 2 has a multi-layer structure, for example, a reinforcing material such as a wire made of metal such as stainless steel, carbon steel, or nickel-titanium alloy can be provided as an intermediate layer of the resin tube that constitutes the shaft 2.

[0029] Examples of resins that make up the shaft 2 include polyamide resins such as polyamide and polyamide elastomer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyphenylene sulfide resin, polystyrene resin, fluororesin, vinyl chloride resin, silicone resin, natural rubber, synthetic rubber, and polyimide. These may be used individually or in combination of two or more. Examples of polyamides include nylon 12 and nylon 11. Examples of polyamide elastomers include polyether ester amide elastomer and polyamide ether elastomer.

[0030] Examples of metals that make up shaft 2 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, Ni-Ti alloy, and Co-Cr alloy. These may be used individually or in combination of two or more.

[0031] As shown in Figures 1 to 5, the proximal basket 21 is positioned at the distal end of the shaft 2. On the other hand, the distal basket 41 is positioned overlapping a portion of the proximal basket 21 in the longitudinal direction x. Partial overlap does not mean overlapping at any single point in the longitudinal direction x, but rather overlapping for an arbitrary length in the longitudinal direction x (for example, 1 cm to 10 cm). As shown in Figure 4, it can also be said that the distal end 21a of the proximal basket 21 is located distal to the proximal end 41b of the distal basket 41. In the catheter 1, the proximal basket 21 and the distal basket 41 exist independently of each other. Hereinafter, for simplicity, both or either of the proximal basket 21 and the distal basket 41 may be referred to as "baskets".

[0032] The basket is capable of expanding and contracting in the radial direction y. Preferably, the basket deflates and reduces in diameter when not subjected to external forces other than gravity, and expands in diameter when subjected to external forces other than gravity. Preferably, the basket has a shape that is convex outward in the radial direction y when it has its maximum outer diameter.

[0033] The basket preferably has a radial and a circumferential direction. In this book, we will explain the case where the radial and circumferential directions of the basket coincide with the radial direction y and circumferential direction z of the shaft 2, but these directions may be different from each other.

[0034] In catheter 1, the timing of the start of expansion of the proximal basket 21 and the start of expansion of the distal basket 41 may be simultaneous. In catheter 1, the start of expansion of either the proximal basket 21 or the distal basket 41 may be later than the other.

[0035] The proximal basket 21 and the distal basket 41 may be expandable independently. That is, the proximal basket 21 and the distal basket 41 may be configured to reach their maximum outer diameter at different times.

[0036] The expansion of the proximal basket 21 and the distal basket 41 may be synchronized. For example, it is preferable that the distal basket 41 expands to its maximum outer diameter when the user operates the handle portion 5 or the traction member 61, which will be described later, followed by the expansion of the proximal basket 21 to its maximum outer diameter.

[0037] The basket preferably has multiple wires. The wires preferably have elasticity and / or flexibility. The elastic wires preferably have a curved shape and / or a bent shape. When an external force is applied to the wires, they preferably bend and / or curve so as to be convex outward in the radial direction y.

[0038] The wire is preferably a single-strand or stranded linear member. The shape of the cross-section perpendicular to the longitudinal direction of the single-strand wire may be, for example, circular, elliptical, polygonal, a part thereof, or a combination thereof, or it may be completely amorphous. Alternatively, it may be a shape with rounded corners.

[0039] It is preferable that a basket is formed by arranging multiple wires at equal or unequal intervals around the longitudinal axis of the shaft 2. One wire may be arranged so that its circumferential position does not change from the distal to the proximal side of the shaft 2, or one wire may be arranged spirally around the longitudinal axis of the shaft 2. The shape of the basket can be changed by adjusting the shape and arrangement of each wire.

[0040] A basket may be formed by connecting the distal ends of multiple wires to each other, and connecting the proximal ends of multiple wires to each other. Preferably, the distal and / or proximal ends of multiple wires are tied together.

[0041] The wire is preferably composed of a metal or resin capable of maintaining the shape of the wire, and more preferably composed of a shape memory alloy or a shape memory resin. As the material constituting the wire, at least one of the metal and / or resin constituting the shaft 2 can be adopted. Among them, the wire is preferably composed of a single wire or a stranded metal wire, and more preferably a metal wire composed of a Ni-Ti alloy.

[0042] The first wire 22 of the proximal basket 21 and the second wire 42 of the distal basket 41 may be composed of the same material or different materials.

[0043] The number of wires of one basket is not limited. For example, it may be 3 or more, 4 or more, 5 or more, 6 or more, 8 or more, 10 or more, or 20 or less, 15 or less.

[0044] The proximal basket 21 preferably has a plurality of first wires 22 arranged in the circumferential direction. The distal basket 41 preferably has a plurality of second wires 42 arranged in the circumferential direction.

[0045] The first wire 22 and the second wire 42 are preferably provided independently. The first wire 22 and the second wire 42 are preferably not joined. The first wire 22 and the second wire 42 are preferably not connected. By separating the first wire 22 and the second wire 42 in this way, it becomes easier to impart a shape suitable for each basket, and it becomes easier to expand each basket independently.

[0046] As a result of the distal basket 41 being arranged to overlap a part of the proximal basket 21 in the longitudinal direction x, when the catheter 1 is viewed from the radial direction y, the first wire 22 and the second wire 42 may intersect. [[ID=As shown in Figures 1 to 5, the proximal basket 21 has an electrode 11. Preferably, the proximal basket 21 has multiple electrodes 11. The distal basket 41 has an electrode 31. Preferably, the distal basket 41 has multiple electrodes 31. The catheter 1 has multiple baskets, and since each basket has an electrode, different functions can be assigned to each basket. For example, one basket can be used to fix the catheter 1 in the body or to measure potential, and the electrodes of the other basket can be used to perform ablation. Also, since the distal basket 41 is arranged overlapping with a part of the proximal basket 21 in the longitudinal direction x, it is easier to bring the distance between the electrodes of these baskets closer together. Therefore, if both of these electrodes are used as ablation electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed efficiently.

[0048] The electrode only needs to be composed of at least a conductive material, and can be made of metallic materials such as copper, gold, platinum, aluminum, iron, or alloys thereof. Furthermore, to improve contrast enhancement to X-rays when using the catheter, the electrode is preferably made of platinum or an alloy thereof.

[0049] It is preferable that the electrodes are connected to a wire, and that the wire is located inside the catheter 1. It is preferable that the handle portion 5 is located at the proximal end of the catheter 1. It is preferable that the wire extends to the proximal end and is connected to a connector via the handle portion 5. It is preferable that the electrodes are electrically connected to external devices such as a power supply unit or an electrocardiogram display unit via the connector.

[0050] The power supply unit applies energy to the body's tissues. The power supply unit has a power source that applies voltage, and by applying pulse voltage, for example, between multiple electrodes or between an electrode and a counter electrode plate, it can supply the electrodes with the power necessary to perform various procedures. The power supply is connected to the electrodes via wires.

[0051] The electrocardiogram display unit displays the intracardiac potential measured by the electrodes of catheter 1 as an intracardiac electrocardiogram. Catheter 1 may be connected to the electrocardiogram display unit via a power supply unit, or it may be connected to the electrocardiogram display unit without going through a power supply unit. An electrocardiograph can be used as an example of an electrocardiogram display unit.

[0052] The conductor only needs to be composed of at least a conductive material, and for example, iron wire, silver wire, stainless steel wire, copper wire, tungsten wire, nickel-titanium wire, etc. can be used. Preferably, the conductor contains a conductive material as a core material, and the core material is covered with an insulating material. As the insulating material, fluororesin (for example, PTFE, PFA, FEP, ETFE), polyolefin resin (for example, polyethylene or polypropylene), polyvinyl chloride resin, etc. can be used.

[0053] It is preferable that electrodes are placed on the outer surface of the wire. This makes it easier to bring the electrodes into contact with body tissue. The electrodes may be placed on the outer surface of the wire, or a recess may be formed on the outer surface of the wire and the electrodes may be embedded in the recess. Electrode material may be printed on the outer surface of the wire. The wire may be inserted into the lumen of the tube, and the electrodes may be placed on top of the tube (preferably on the outer surface of the tube). For the configuration of the tube, refer to the description of shaft 2.

[0054] The number of electrodes 11 in the proximal basket 21 may be greater than or less than the number of electrodes 31 in the distal basket 41, or they may be the same number.

[0055] Electrodes may be placed on all the wires in a single basket. Or, electrodes may be placed on only some of the wires among the multiple wires in a single basket.

[0056] A single wire may have only one electrode, or it may have multiple electrodes.

[0057] Preferably, the first wire 22 has a plurality of electrodes 11 arranged along the direction of extension of the first wire 22. Preferably, the second wire 42 has a plurality of electrodes 31 arranged along the direction of extension of the second wire 42.

[0058] The distal basket 41 is preferably located distal to the distal end 2a of the shaft 2. It is also preferable that the distal basket 41 is not joined to the shaft 2.

[0059] It is preferable that neither the proximal basket 21 nor the distal basket 41 is arranged to completely enclose the other.

[0060] The distal end 21a of the proximal basket 21 refers to the most distal position visible in a lateral view of the catheter 1, excluding any portion that is covered by other components and therefore not visible. The same applies to the proximal end 21b of the proximal basket 21, and the distal end 41a and proximal end 41b of the distal basket 41.

[0061] As shown in Figure 4, it is preferable that in the longitudinal direction x, the distal end 21a of the proximal basket 21 is located between the distal end 41a of the distal basket 41 and the maximum outer diameter position 41c. By positioning the distal end 21a in this manner, the two baskets are more likely to overlap over a wide area.

[0062] As shown in Figure 4, in the longitudinal direction x, it is preferable that the proximal end 41b of the distal basket 41 is located between the maximum outer diameter position 21c of the proximal basket 21 and the proximal end 21b. By positioning the proximal end 41b in this manner, the two baskets are more likely to overlap over a wide area.

[0063] As shown in Figure 7, in the longitudinal direction x, it is preferable that the distal end 21a of the proximal basket 21 is located between the proximal end 41b of the distal basket 41 and the maximum outer diameter position 41c of the distal basket 41. By positioning the proximal end 41b in this manner, it becomes easier to obtain a catheter in which the combined length of the proximal basket 21 and the distal basket 41 is longer than that of the catheter shown in Figure 4, while overlapping the two baskets within an appropriate range. In this document, the combined length of the proximal basket 21 and the distal basket 41 refers to the length from the distal end 41a of the distal basket 41 to the proximal end 21b of the proximal basket 21 in the longitudinal direction x.

[0064] As shown in Figure 7, in the longitudinal direction x, it is preferable that the proximal end 41b of the distal basket 41 is located between the maximum outer diameter position 21c of the proximal basket 21 and the distal end 21a of the proximal basket 21. By positioning the proximal end 41b in this manner, it becomes easier to obtain a catheter in which the total length of the proximal basket 21 and the distal basket 41 is longer than that of the catheter shown in Figure 4, while overlapping the two baskets within an appropriate range.

[0065] Although not shown in the figures, in the longitudinal direction x, the distal end 21a of the proximal basket 21 may be located between the distal end 41a of the distal basket 41 and the maximum outer diameter position 41c, and the proximal end 41b of the distal basket 41 may be located between the maximum outer diameter position 21c of the proximal basket 21 and the distal end 21a. Also, in the longitudinal direction x, the distal end 21a of the proximal basket 21 may be located between the proximal end 41b of the distal basket 41 and the maximum outer diameter position 41c, and in the longitudinal direction x, the proximal end 41b of the distal basket 41 may be located between the maximum outer diameter position 21c of the proximal basket 21 and the proximal end 21b.

[0066] As shown in Figure 8, it is preferable that the proximal end 41b of the distal basket 41 is in the same position as the proximal end 21b of the proximal basket 21 in the longitudinal direction x. By positioning the proximal end 41b in this way, the entire proximal basket 21 can be made to overlap with the distal basket 41.

[0067] As shown in Figures 4 and 7, when both the proximal basket 21 and the distal basket 41 are fully expanded, the catheter 1 may have, in the longitudinal direction x, a first portion 51 where the proximal basket 21 and the distal basket 41 overlap, and a second portion 52 of the proximal basket 21 that does not overlap with the distal basket 41. By providing the first portion 51 in this way, it becomes easier to reduce the distance between the electrodes of the proximal basket 21 and the distal basket 41. As a result, the energy density when current is passed between the electrodes can be increased, so that the ablation procedure can be performed efficiently.

[0068] As shown in Figure 4, when both the distal basket 41 and the proximal basket 21 are in their most expanded state, it is preferable that the length of the first portion 51 is longer than the length of the second portion 52. Setting the first portion 51 in this way makes it easier to reduce the distance between the electrodes of the proximal basket 21 and the distal basket 41. Here, the length of the first portion 51 and the length of the second portion 52 refer to the length in the longitudinal direction x.

[0069] As shown in Figure 7, when both the distal basket 41 and the proximal basket 21 are fully expanded, the length of the first portion 51 may be shorter than the length of the second portion 52. By setting the first portion 51 in this way, it becomes easier to obtain a catheter in which the sum of the lengths of the proximal basket 21 and the distal basket 41 is longer than that of the catheter shown in Figure 4, while overlapping the two baskets within an appropriate range.

[0070] In Figures 4, 7, and 8, with both the proximal basket 21 and the distal basket 41 fully expanded, the catheter 1 has a third portion 53 in the longitudinal direction x that does not overlap with the proximal basket 21 of the distal basket 41. As shown in Figure 4, it is preferable that the third portion 53 is shorter than the first portion 51 in the longitudinal direction x. As shown in Figure 7, the third portion 53 may be longer than the first portion 51 in the longitudinal direction x. The third portion 53 may be longer than the second portion 52, or shorter than the second portion 52.

[0071] As shown in Figure 8, when both the proximal basket 21 and the distal basket 41 are fully expanded, the catheter 1 may have the entire proximal basket 21 overlapping the distal basket 41 in the longitudinal direction x. That is, the catheter 1 may have a first portion 51 and a third portion 53, but may not have a second portion 52.

[0072] The proximal basket 21 preferably has at least one of an electrode for cauterization and an electrode for potential measurement. The distal basket 41 preferably has at least one of an electrode for cauterization and an electrode for potential measurement.

[0073] It is preferable that both the electrode 11 of the proximal basket 21 and the electrode 31 of the distal basket 41 are electrodes for cauterization. This allows for cauterization of a wide area by electrodes 11 and 31 which are positioned far apart, thus enabling the procedure to be performed efficiently.

[0074] As shown in Figure 5, the proximal basket 21 may have only an electrode 91 for cauterization and may not have an electrode for potential measurement. In other words, all the electrodes 11 on the proximal basket 21 may be an electrode 91 for cauterization. In that case, the distal basket 41 may have only an electrode 92 for potential measurement and may not have an electrode for cauterization. In other words, all the electrodes 31 on the distal basket 41 may be an electrode 92 for potential measurement. By measuring the potential using the electrode 31 of the distal basket 41 which is introduced into the body first, and then pushing the catheter 1 distally, cauterization can be performed with the electrode 11 of the proximal basket 21 which is inserted following, thus enabling the procedure to be performed efficiently.

[0075] In another example, as shown in Figure 6, the proximal basket 21 may have only an electrode 92 for potential measurement and not an electrode for cauterization. That is, all the electrodes 11 on the proximal basket 21 may be electrodes 92 for potential measurement. In that case, the distal basket 41 may have only an electrode 91 for cauterization and not an electrode for potential measurement. That is, all the electrodes 31 on the distal basket 41 may be electrodes 91 for cauterization. Since potential measurement can be performed with the electrode 11 of the proximal basket 21 located at the front, and then cauterization can be performed with the electrode 31 of the distal basket 41 located at the back, the procedure can be performed efficiently.

[0076] Although not shown in the diagram, of the multiple electrodes 11 in the proximal basket 21, at least one may be a cauterization electrode 91, and the remaining electrodes 11 may be potential measurement electrodes 92. Similarly, of the multiple electrodes 31 in the distal basket 41, at least one may be a cauterization electrode 91, and the remaining electrodes 11 may be potential measurement electrodes 92.

[0077] Although not shown in the diagram, the electrode 11 of the proximal basket 21 may serve as both a cauterization electrode 91 and a potential measurement electrode 92. Similarly, the electrode 31 of the distal basket 41 may serve as both a cauterization electrode 91 and a potential measurement electrode 92.

[0078] Current may be passed between the multiple electrodes 11 of the proximal basket 21. Current may be passed between the multiple electrodes 31 of the distal basket 41. Also, current may be passed between the electrodes 11 of the proximal basket 21 and the electrodes 31 of the distal basket 41.

[0079] As shown in Figures 1 to 3, it is preferable that the handle portion 5 has a first connector 81 that is connected to the electrode for cauterization but not to the electrode for potential measurement and is connected to the power supply unit, and a second connector 82 that is connected to the electrode for potential measurement but not to the electrode for cauterization and is connected to the electrocardiogram display unit. In Figures 1 to 3, the handle portion 5 includes a first handle 6 connected to the proximal part of the shaft 2, and the first handle 6 is provided with the first connector 81 and the second connector 82.

[0080] Next, we will describe the mechanism for expanding the basket.

[0081] As shown in Figures 5 to 6, if the shaft 2 has a lumen 2c extending in the longitudinal direction x, it is preferable that the catheter 1 has a traction member 61 that extends in the longitudinal direction x, is connected to at least one of the proximal basket 21 and the distal basket 41, is inserted into the lumen 2c of the shaft 2, and is movable in the longitudinal direction x relative to the shaft 2. The traction member 61 transmits the operation on the proximal side to the proximal basket 21 and / or the distal basket 41. It is preferable that the proximal basket 21 and the distal basket 41 expand as the traction member 61 moves proximal to the shaft 2. Figures 5 to 6 show an example in which the traction member 61 is connected to the distal basket 41.

[0082] In Figures 1 to 3, the handle portion 5 has a first handle 6 connected to the proximal part of the shaft 2 and a second handle 7 connected to the proximal part of the traction member 61. As shown in Figures 5 to 6, it is preferable that the first handle 6 has a hollow portion 6c inside, and it is preferable that the traction member 61 is inserted through the hollow portion 6c.

[0083] The traction member 61 preferably has an elongated shape. The traction member 61 may be a single wire or may have a structure consisting of multiple linear objects. The traction member 61 preferably extends along the longitudinal direction x of the shaft 2. The shaft 2 may have a distal opening and a proximal opening that communicate with the lumen 2c. As can be seen from Figures 5 and 6, the traction member 61 preferably extends from the distal opening of the shaft 2. The traction member 61 preferably extends from the proximal side of the first handle 6. The proximal opening of the shaft 2 preferably communicates with the hollow portion 6c of the first handle 6.

[0084] The traction member 61 may have a solid shape or a hollow shape. A cylindrical body can be an example of a hollow traction member 61. The traction member 61 may be a solid metal wire or resin wire covered by a cylindrical body made of coiled metal and / or synthetic resin.

[0085] The traction member 61 can be made of, for example, metals such as stainless steel, carbon steel, and nickel-titanium alloy, or synthetic resins such as polyamide resin (e.g., nylon), polyolefin resin (e.g., polyethylene and polypropylene), polyester resin (e.g., PET), aromatic polyetherketone resin (e.g., PEEK), polyimide resin, and fluororesin (e.g., PTFE, PFA, FEP, ETFE).

[0086] As shown in Figures 5 and 6, the catheter 1 may have a first connection portion 71 to which the distal end of the traction member 61 and the distal end of the distal basket 41 are connected. With this configuration, the distal basket 41 can be expanded or contracted by moving the traction member 61 distally or proximal. As shown in Figure 5, it is preferable that the distal end of the traction member 61 and the plurality of second wires 42 constituting the distal basket 41 are connected to each other at the first connection portion 71.

[0087] The connection method at the first connection part 71 can include methods such as welding, silver brazing, soldering, crimping, bonding with adhesive, engagement, fitting, linking, bundling, and other physical fixing methods, or combinations thereof. At least one of these methods can also be used when connecting the second connection part 72, third connection part 73, fourth connection part 74, and at least two other elements, as described later. Here, "connection" includes both forms in which at least two elements are directly connected and forms in which at least two elements are indirectly connected via one or more other elements.

[0088] In the first connection section 71, the traction member 61 and the second wire 42 may or may not be in contact with each other.

[0089] As shown in Figures 5 and 6, the first connection portion 71 may be connected to the traction member 61 and the plurality of second wires 42 by a tip 64. The shape of the tip 64 is not particularly limited, but the tip 64 may have one or more insertion openings in at least a portion of the longitudinal direction x of the shaft 2 into which the distal ends of the plurality of second wires 42 and / or the traction member 61 are inserted. For example, in Figure 5, the tip 64 has a first insertion opening 64m into which the distal end of the traction member 61 is inserted, and a second insertion opening 64n into which the distal ends of the plurality of second wires 42 are inserted.

[0090] In the radial direction y of the shaft 2, it is preferable that the second insertion opening 64n is positioned outward from the first insertion opening 64m. In the radial direction y of the shaft 2, it is preferable that the first insertion opening 64m is positioned so as to coincide with the central axis in the longitudinal direction x of the shaft 2.

[0091] A recess provided on the outer side of the tip 64 in the radial direction y may be a second insertion opening 64n. The tip 64 may have an outer cylinder portion and an inner cylinder portion, and the space between the outer cylinder portion and the inner cylinder portion may be the second insertion opening 64n. One or more second insertion openings 64n may be provided.

[0092] The tip 64 can be made of the same material as at least one of the first wire 22, the second wire 42, the traction member 61, and the shaft 2.

[0093] As shown in Figures 5 and 6, the catheter 1 is a cylindrical member 65 positioned distal to the distal end of the shaft 2 and proximal to the first connection portion 71, with a traction member 61 inserted into the lumen 65c of the cylindrical member 65. The cylindrical member 65 may also have a second connection portion 72 to which the proximal end of the distal basket 41 is connected to the cylindrical member 65. With this configuration, when the traction member 61 moves distally or proximal, the cylindrical member 65 moves relative to the traction member 61, and the distance from the first connection portion 71 to the second connection portion 72 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the distal basket 41.

[0094] The cylindrical member 65 is a member for binding the first wire 22 of the proximal basket 21 and the second wire 42 of the distal basket 41. The cylindrical member 65 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 65 is movable distally or proximal relative to the traction member 61. It is preferable that the cylindrical member 65 is not fixed to the traction member 61.

[0095] The cylindrical member 65 can be made from the same material as at least one of the first wire 22, the second wire 42, the traction member 61, the shaft 2, and the tip 64.

[0096] As shown in Figure 5, it is preferable that a first insertion opening 65m is provided on the outer side of the cylindrical member 65 in the radial direction y, into which the proximal end of the second wire 42 of the distal basket 41 is inserted. The second wire 42 may be inserted into the first insertion opening 65m and the cylindrical member 65 may be crimped from the outside. The first insertion opening 65m may be a recess provided on the outer side of the cylindrical member 65 in the radial direction y. The cylindrical member 65 may have an outer cylinder and an inner cylinder, and the space between the outer cylinder and the inner cylinder may be the first insertion opening 65m. It is preferable that the first insertion opening 65m is located radially outward in the y direction from the lumen 65c of the cylindrical member 65.

[0097] Although not shown in the diagram, the second wire 42 can be connected to any part of the cylindrical member 65 as long as it does not obstruct the movement of the traction member 61. For example, the second connection portion 72 may be formed by joining the second wire 42 to the outer surface of the cylindrical member 65.

[0098] As shown in Figures 5 and 6, the catheter 1 may have a third connection portion 73 to which the distal end of the proximal basket 21 and the cylindrical member 65 are connected. This configuration allows the proximal basket 21 to expand or contract as the traction member 61 moves distally or proximal. Preferably, the distal end of the traction member 61 and the plurality of first wires 22 constituting the proximal basket 21 are connected to each other at the third connection portion 73.

[0099] In the third connection section 73, the distal end of the proximal basket 21 can be connected to the cylindrical member 65 in the same manner as in the second connection section 72, except that the point of connection of the wire is either the distal end or the proximal end. Figure 5 shows an example in which the cylindrical member 65 has a second insertion port 65n into which the distal end of the proximal basket 21 is inserted.

[0100] In the cylindrical member 65, it is preferable that the second insertion opening 65n is located distal to the first insertion opening 65m. By arranging the first insertion opening 65m and the second insertion opening 65n in this way, the two baskets are more likely to overlap over a wide area.

[0101] As shown in Figures 5 and 6, the catheter 1 may have a fourth connection portion 74 to which the proximal end of the proximal basket 21 and the distal end of the shaft 2 are connected. With this configuration, as the traction member 61 moves distally or proximal, the proximal basket 21 curves and / or bends, and the distance from the third connection portion 73 to the fourth connection portion 74 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the proximal basket 21. Preferably, at the fourth connection portion 74, the first wire 22 constituting the proximal basket 21 and the shaft 2 are connected to each other.

[0102] In the fourth connection section 74, the proximal end of the proximal basket 21 can be connected to the distal end of the shaft 2 in the same manner as in the second connection section 72. Figure 5 shows an example in which the shaft 2 has an insertion opening 2f into which the proximal end of the first wire 22 is inserted. It is preferable that the multiple first wires 22 are not fixed to the traction member 61 in the fourth connection section 74.

[0103] As shown in Figure 5, in the longitudinal direction x, the distal end of the insertion port 2f of the shaft 2 may be at the same position as the distal end of the lumen 2c of the shaft 2. In the longitudinal direction x, the distal end of the insertion port 2f of the shaft 2 may be located proximal to the distal end of the lumen 2c. In the radial direction y, it is preferable that the insertion port 2f is positioned outward from the lumen 2c.

[0104] Although not shown in the diagram, the first wire 22 and the cylindrical member 65 may be in contact when the proximal basket 21 is in its most expanded state, and the inner surface of the proximal basket 21 in the radial direction y may be in contact with the proximal end of the cylindrical member 65.

[0105] As can be seen from Figure 5, it is preferable that the cylindrical member 65 and the tip 64 are in contact when the distal basket 41 is in its most expanded state, and it is even more preferable that the distal end of the cylindrical member 65 and the proximal end of the tip 64 are in contact.

[0106] As can be seen from Figure 4, it is preferable that the cylindrical member 65 and the second wire 42 are in contact when the distal basket 41 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 65 and the inner surface of the distal basket 41 in the radial direction y are in contact.

[0107] Although not shown in the diagram, when the proximal basket 21 is in its most expanded state, the cylindrical member 65 and the shaft 2 may be in contact, or the proximal end of the cylindrical member 65 and the distal end of the shaft 2 may be in contact.

[0108] Other basket expansion mechanisms will be described with reference to Figures 8 and 9. If the shaft 2 has a lumen 2c extending in the longitudinal direction x, the catheter 1 may further include: a traction member 61 extending in the longitudinal direction x, connected to at least one of the proximal basket 21 and the distal basket 41, inserted into the lumen 2c of the shaft 2 and movable in the longitudinal direction x relative to the shaft 2; a first connection portion 71 to which the distal end of the traction member 61 and the distal end of the distal basket 41 are connected; and a cylindrical member 66 positioned distal to the distal end of the shaft 2 and proximal to the first connection portion 71, with the traction member 61 inserted into the lumen of the cylindrical member 66 and movable in the longitudinal direction x of the traction member 61. In this case, it is preferable that the distal end of the proximal basket 21 and the cylindrical member 66 are connected, and the proximal end of the distal basket 41 and the proximal end of the proximal basket 21 and the distal end of the shaft 2 are connected. With this configuration, moving the traction member 61 proximal to the other side causes the proximal basket 21 and distal basket 41 to curve or bend, shortening the distance from the first connection part 71 to the distal end of the shaft 2 in the longitudinal direction x, and the distance from the distal end of the proximal basket 21 to the distal end of the shaft 2 in the longitudinal direction x. In this way, by pulling the traction member 61, the proximal basket 21 and distal basket 41 can be expanded together or sequentially.

[0109] For the configuration of the first connection part 71 shown in Figures 8 to 9, please refer to the explanation of the first connection part 71 shown in Figures 5 to 6.

[0110] The cylindrical member 66 is a member for binding the first wire 22 of the proximal basket 21. The cylindrical member 66 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 66 is movable distally or proximal relative to the traction member 61. It is preferable that the cylindrical member 66 is not fixed to the traction member 61.

[0111] The cylindrical member 66 can be made of the same material as at least one of the first wire 22, the second wire 42, the traction member 61, the shaft 2, and the tip 64.

[0112] For information on how to connect the distal end of the proximal basket 21 to the cylindrical member 66, please refer to the explanation of the third connection part 73 shown in Figures 5 to 6.

[0113] For information on how to connect the proximal end of the distal basket 41, the proximal end of the proximal basket 21, and the distal end of the shaft 2, please refer to the explanation of the fourth connection part 74 shown in Figures 5 to 6.

[0114] Further expansion mechanisms of the basket will be described with reference to Figures 10 to 11. The shaft 2 has a lumen 2c extending in the longitudinal direction x, and the catheter 1 extends in the longitudinal direction x and is connected to at least one of the proximal basket 21 and the distal basket 41, is inserted into the lumen 2c of the shaft 2, and may further have a traction member 61 that is movable in the longitudinal direction x relative to the shaft 2, and a first connection part 71 to which the distal end of the traction member 61 and the distal end of the distal basket 41 are connected. In this case, it is preferable that the distal end of the proximal basket 21 and the longitudinal middle part of the traction member 61 are connected, and the proximal end of the distal basket 41 and the proximal end of the proximal basket 21 and the distal end of the shaft 2 are connected. Since the distal end of the proximal basket 21 and the middle of the longitudinal direction of the traction member 61 are connected, the distance from the first connection part 71 to the distal end of the proximal basket 21 in the longitudinal direction x does not change even when the traction member 61 is moved in the longitudinal direction x. On the other hand, in the longitudinal direction x, the distance from the distal end of the proximal basket 21 to the distal end of the shaft 2 changes depending on the degree to which the traction member 61 is pulled proximal. Specifically, as the traction member 61 moves proximal, the proximal basket 21 and the distal basket 41 curve and / or bend, and the distance from the first connection part 71 to the distal end of the shaft 2 in the longitudinal direction x, and the distance from the distal end of the proximal basket 21 to the distal end of the shaft 2 in the longitudinal direction x, become shorter. In this way, by pulling the traction member 61, the proximal basket 21 and the distal basket 41 can be expanded together or sequentially.

[0115] One end of the traction member 61 refers to a range of 5% of the total length of the traction member 61, the other end of the traction member 61 refers to a range of 5% of the total length of the traction member 61, and the middle section of the traction member 61 refers to the remaining 90% of the length of the traction member 61 excluding the one end and the other end. Preferably, the distal end of the proximal basket 21 is connected to the distal section of the middle section of the traction member 61 when the total length of the middle section is divided into three equal parts.

[0116] It is preferable that the distal end of the first wire 22 is fixed to the traction member 61, and more preferably that it is joined to it. This causes the proximal basket 21 to expand as the distance from the distal end of the first wire 22 to the distal end of the shaft 2 shortens when the traction member 61 moves proximal. Also, when the traction member 61 moves proximal, the distance from the first connection part 71 to the distal end of the shaft 2 shortens, causing the distal basket 41 to expand.

[0117] It is preferable that the distal end of the first wire 22 is fixed to the middle part of the traction member 61 and does not move. It is also preferable that the distal end of the first wire 22 does not move relative to the longitudinal direction of the traction member 61.

[0118] Figure 11 shows an example in which the distal end of the first wire 22 is bound by a cylindrical member 67, and the inner wall defining the lumen of the cylindrical member 67 is fixed to the outer surface of the middle portion of the traction member 61. However, the method of connecting the distal end of the proximal basket 21 and the middle portion of the traction member 61 is not limited to this. As a method of connecting the proximal basket 21 and the traction member 61, at least one of the methods listed for connection at the first connection portion 71 can be used.

[0119] For details regarding the configuration of the cylindrical member 67, please refer to the description of the cylindrical members 65 and 66.

[0120] As shown in Figure 12, when viewing the catheter 1 from distal to proximal, it is preferable that the first wire 22 and the second wire 42 are arranged alternately in the circumferential direction. It is preferable that the first wire 22 and the second wire 42 are arranged alternately in the circumferential direction when both the distal basket 41 and the proximal basket 21 are at their most expanded state. It is also preferable that the first wire 22 and the second wire 42 are arranged alternately in the circumferential direction when both the distal basket 41 and the proximal basket 21 are at their most contracted state.

[0121] As shown in Figure 13, it is preferable that the first wire 22 and the second wire 42 are arranged to overlap when the catheter 1 is viewed from the distal to the proximal end. In this case, a part of the first wire 22 and a part of the second wire 42 may overlap each other in the circumferential direction, or the entire first wire 22 may overlap with the second wire 42.

[0122] As shown in Figure 12, it is preferable that the first wire 22 and the second wire 42 are separated when both the distal basket 41 and the proximal basket 21 are at their most expanded state. It is also preferable that the first wire 22 and the second wire 42 are separated in the first portion 51 when both the distal basket 41 and the proximal basket 21 are at their most expanded state. It is also preferable that the first wire 22 and the second wire 42 are separated in the second portion 52 when both the distal basket 41 and the proximal basket 21 are at their most expanded state. When both the distal basket 41 and the proximal basket 21 are at their most expanded state and are divided into an outer portion and an inner portion in the radial direction y, it is preferable that the outer portion of the distal basket 41 and the outer portion of the proximal basket 21 are separated.

[0123] As can be seen from Figures 1 and 2, it is preferable that the first wire 22 and the second wire 42 are in contact when at least one of the distal basket 41 and the proximal basket 21 is at its most contracted state. It is more preferable that the first wire 22 and the second wire 42, which are adjacent to each other in the circumferential direction, are in contact when at least one of the distal basket 41 and the proximal basket 21 is at its most contracted state. It is preferable that the first wire 22 and the second wire 42 are in contact in the first portion 51 when at least one of the distal basket 41 and the proximal basket 21 is at its most contracted state. It is preferable that the first wire 22 and the second wire 42 are separated in the second portion 52 when at least one of the distal basket 41 and the proximal basket 21 is at its most contracted state.

[0124] As shown in Figures 3 to 5, it is preferable that electrodes are placed in the distal basket 41 and the proximal basket 21, respectively, in the first portion 51 when both the distal basket 41 and the proximal basket 21 are in their most expanded state. It is preferable that all of these electrodes are electrodes for cauterization.

[0125] Although not shown in the diagram, it is preferable that, in the fully expanded state of both the distal basket 41 and the proximal basket 21, electrodes for measuring potential are placed in the second portion 52 of the proximal basket 21 and electrodes for measuring potential are placed in the third portion 53 of the distal basket 41.

[0126] It is preferable that the cauterizing electrode is positioned proximal to the portion of the first wire 22 where the first wire 22 and the second wire 42 intersect.

[0127] It is preferable that the cauterizing electrode is positioned distal to the portion of the first wire 22 where the first wire 22 and the second wire 42 intersect.

[0128] It is preferable that the cauterizing electrode is positioned on the side of the second wire 42 that is proximal to the portion where the first wire 22 and the second wire 42 intersect.

[0129] It is preferable that the cauterizing electrode is positioned distal to the portion of the second wire 42 where the first wire 22 and the second wire 42 intersect.

[0130] An electrode for cauterization may be placed in the portion of the first wire 22 where the first wire 22 and the second wire 42 intersect.

[0131] An electrode for cauterization may be placed in the portion of the second wire 42 where the first wire 22 and the second wire 42 intersect.

[0132] As shown in Figure 4, when both the distal basket 41 and the proximal basket 21 are in their most expanded state, it is preferable that the maximum outer diameter of the proximal basket 21 is larger than the maximum outer diameter of the distal basket 41. This makes it easier to bring the distal basket 41 into contact with the inner wall of the pulmonary vein and the proximal basket 21 into contact with the antrum of the pulmonary vein.

[0133] Even when both the distal basket 41 and the proximal basket 21 are fully expanded, the maximum outer diameter of the proximal basket 21 may be smaller than the maximum outer diameter of the distal basket 41. This makes it easier to use when you want to firmly fix the catheter 1 inside the body with the distal basket 41, or when the antrum of the pulmonary veins is elevated due to a lesion or the like, and a smaller outer diameter of the proximal basket 21 is preferable.

[0134] The catheter according to the second embodiment is an ablation catheter. Hereinafter, in the description of the second embodiment, the ablation catheter may be simply referred to as a catheter. The catheter according to the second embodiment of this disclosure is characterized by having a longitudinal shaft, a proximal basket having a first electrode for performing either ablation or potential measurement and positioned distal to the shaft, and a distal basket having a second electrode for performing either ablation or potential measurement and positioned distal to the proximal basket in the longitudinal direction, at least a portion of which is positioned distal to the proximal basket. In the above ablation catheter, if the first electrode of the proximal basket is for ablation and the second electrode of the distal basket is for potential measurement, the procedure can be performed efficiently by first measuring the potential using the second electrode of the distal basket which is introduced into the body first, and then performing ablation with the first electrode of the proximal basket. Also, if the first electrode of the proximal basket is for potential measurement and the second electrode of the distal basket is for ablation, the procedure can be performed efficiently by first measuring the potential with the first electrode on the front side and then performing ablation with the second electrode on the back side.

[0135] A catheter according to a second embodiment of the present disclosure will be described with reference to Figures 14 to 29. Figures 14 to 16 are side views of a catheter according to a second embodiment of the present disclosure. Figure 14 shows the proximal basket and distal basket in a contracted state. Figure 15 shows the proximal basket in an expanded state and the distal basket in a contracted state. Figure 16 shows the proximal basket and distal basket in an expanded state. Figure 17 is an enlarged side view of the distal side of the catheter shown in Figure 16. Figure 18 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 17. Figure 19 is a cross-sectional view (partial side view) showing a modified example of the catheter shown in Figure 18. Figure 20 is a side view showing a modified example of the catheter shown in Figure 17. Figure 21 is a side view showing a modified example of the catheter shown in Figure 17. Figure 22 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 21. Figure 23 is a side view showing a modified example of the catheter shown in Figure 21. Figure 24 is a side view showing another modified example of the catheter shown in Figure 17. Figure 25 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 24. Figure 26 is a side view showing another modified example of the catheter shown in Figure 17. Figure 27 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 26. Figures 28 to 29 are schematic diagrams showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side of a catheter according to the second embodiment of this disclosure. Note that some wires are omitted in the diagrams showing the connection state of each component. As shown in Figures 14 to 18, the catheter 101 has a shaft 102, a proximal basket 121 having a first electrode 111, and a distal basket 141 having a second electrode 131.

[0136] As shown in Figures 14 to 16, the shaft 102 has a longitudinal direction x. As shown in Figure 18, the shaft 102 preferably has a distal end 102a and a proximal end 102b in the longitudinal direction x. The proximal side of the shaft 102 refers to the direction toward the user or operator's hand relative to the longitudinal direction x of the shaft 102, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. In each drawing, the right side of the figure is the proximal side, and the left side of the figure is the distal side. The shaft 102 preferably has a radial direction y and a circumferential direction z. The radial direction y refers to the radial direction of the shaft 102, in which case inward refers to the direction toward the center of the longitudinal axis of the shaft 102, and outward refers to the direction extending radially from the center of the longitudinal axis on the opposite side from inward. The circumferential direction z refers to the direction around the longitudinal axis of the shaft 102, i.e., the direction along the outer circumference of the shaft 102.

[0137] The shaft 102 can be composed of one or more members. Examples of the shaft 102 include a resin tube, a metal tube, a hollow body formed by arranging wires in a predetermined pattern, a hollow body with at least one of its inner or outer surfaces coated with resin, or a combination thereof, for example, a shaft connected in the longitudinal direction x. The resin tube can be manufactured, for example, by extrusion molding. Examples of hollow bodies with wires arranged in a predetermined pattern include cylindrical bodies having a mesh structure by simply crossing or weaving wires, and coils in which wires are wound. The wires may be one or more single wires or one or more stranded wires. The type of mesh structure is not particularly limited, nor are the number of turns or density of the coils. The mesh structure or coil may be formed at a constant density over the entire longitudinal direction x of the shaft 102, or it may be formed so that the density differs depending on the position in the longitudinal direction x. To increase the flexibility of the metal tube, notches or grooves may be formed on the outer surface of the metal tube. The shape of the cuts and grooves can be straight, arcuate, annular, spiral, or a combination of these.

[0138] The shaft 102 preferably has one or more lumens, and more preferably has only one. The shaft 102 is preferably a single-lumen tube.

[0139] The shaft 102 is preferably flexible and elastic. The material constituting the shaft 102 is preferably resin, metal, or a combination of resin and metal. Using resin makes it easier to impart flexibility and elasticity to the shaft 102. Using metal can improve the ease of insertion of the catheter 101 into the vascular lumen.

[0140] The shaft 102 may have a single-layer structure or a multi-layer structure. If the shaft 102 has a multi-layer structure, for example, a reinforcing material such as a wire made of metal such as stainless steel, carbon steel, or nickel-titanium alloy can be provided as an intermediate layer of the resin tube that constitutes the shaft 102.

[0141] Examples of resins that make up the shaft 102 include polyamide resins such as polyamide and polyamide elastomer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyphenylene sulfide resin, polystyrene resin, fluororesin, vinyl chloride resin, silicone resin, natural rubber, synthetic rubber, and polyimide. These may be used individually or in combination of two or more. Examples of polyamides include nylon 12 and nylon 11. Examples of polyamide elastomers include polyether ester amide elastomer and polyamide ether elastomer.

[0142] Examples of metals that make up the shaft 102 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, Ni-Ti alloy, and Co-Cr alloy. These may be used individually or in combination of two or more.

[0143] As shown in Figures 14 to 18, the catheter 101 has a proximal basket 121 located distal to the shaft 102 and having a first electrode 111 for performing either cauterization or electrometry, and a distal basket 141 located distal to the proximal basket 121 in the longitudinal direction x and having a second electrode 131 for performing either cauterization or electrometry. In the catheter 101, the proximal basket 121 and the distal basket 141 exist independently of each other. Hereinafter, for simplicity, both or either of the proximal basket 121 and the distal basket 141 may be referred to as the "basket".

[0144] The basket is capable of expanding and contracting in the radial direction y. Preferably, the basket deflates and reduces in diameter when not subjected to external forces other than gravity, and expands in diameter when subjected to external forces other than gravity. Preferably, the basket has a shape that is convex outward in the radial direction y when it has its maximum outer diameter.

[0145] The basket preferably has a radial and a circumferential direction. In this document, the case in which the radial and circumferential directions of the basket coincide with the radial direction y and circumferential direction z of the shaft 102 is given as an example, but these directions may be different from each other.

[0146] In catheter 101, the timing of the start of expansion of the proximal basket 121 and the start of expansion of the distal basket 141 may be simultaneous. In catheter 101, the start of expansion of either the proximal basket 121 or the distal basket 141 may be later than the other.

[0147] The proximal basket 121 and the distal basket 141 may be expandable independently. That is, the proximal basket 121 and the distal basket 141 may be configured to reach their maximum outer diameter at different times.

[0148] The expansion of the proximal basket 121 and the distal basket 141 may be synchronized. For example, it is preferable that the distal basket 141 expands to its maximum outer diameter when the user operates the handle portion 105 or the traction member 161, which will be described later, followed by the proximal basket 121 expanding to its maximum outer diameter.

[0149] The basket preferably has multiple wires. The wires preferably have elasticity and / or flexibility. The elastic wires preferably have a curved shape and / or a bent shape. When an external force is applied to the wires, they preferably bend and / or curve so as to be convex outward in the radial direction y.

[0150] The wire is preferably a single-strand or stranded linear member. The shape of the cross-section perpendicular to the longitudinal direction of the single-strand wire may be, for example, circular, elliptical, polygonal, a part thereof, or a combination thereof, or it may be completely amorphous. Alternatively, it may be a shape with rounded corners.

[0151] It is preferable that a basket is formed by arranging multiple wires at equal or unequal intervals around the longitudinal axis of the shaft 102. One wire may be arranged so that its circumferential position does not change from the distal to the proximal side of the shaft 102, or one wire may be arranged spirally around the longitudinal axis of the shaft 102. The shape of the basket can be changed by adjusting the shape and arrangement of each wire.

[0152] A basket may be formed by connecting the distal ends of multiple wires to each other, and connecting the proximal ends of multiple wires to each other. Preferably, the distal and / or proximal ends of multiple wires are tied together.

[0153] The wire is preferably made of a metal or resin capable of maintaining its shape, and more preferably made of a shape memory alloy or shape memory resin. As the material for the wire, at least one of the metals and / or resins that make up the shaft 102 can be used. In particular, the wire is preferably made of a single or stranded metal wire, and more preferably a metal wire made of a Ni-Ti alloy.

[0154] The first wire 122 of the proximal basket 121 and the second wire 142 of the distal basket 141 may be made of the same material or of different materials.

[0155] There is no limit to the number of wires a single basket may have, but for example, it may be three or more, four or more, five or more, six or more, eight or more, ten or more, or twenty or fewer, or fifteen or fewer.

[0156] The proximal basket 121 preferably has a plurality of first wires 122 arranged in the circumferential direction. The distal basket 141 preferably has a plurality of second wires 142 arranged in the circumferential direction.

[0157] It is preferable that the first wire 122 and the second wire 142 are provided independently. It is preferable that the first wire 122 and the second wire 142 are not joined together. It is preferable that the first wire 122 and the second wire 142 are not connected. By separating the first wire 122 and the second wire 142 in this way, it becomes easier to impart a shape suitable for each individual basket and to expand each basket independently.

[0158] As shown in Figures 14 to 17, the proximal basket 121 has a first electrode 111 for performing either cauterization or potential measurement. Preferably, the proximal basket 121 has a plurality of first electrodes 111. The distal basket 141 has a second electrode 131 for performing either cauterization or potential measurement. Preferably, the distal basket 141 has a plurality of second electrodes 131.

[0159] The first electrode 111 and the second electrode 131 may be composed of at least a conductive material, and can be made of metallic materials such as copper, gold, platinum, aluminum, iron, or alloys thereof. In order to improve contrast enhancement to X-rays when using the catheter, it is preferable that the electrodes be made of platinum or an alloy thereof.

[0160] It is preferable that the first electrode 111 and the second electrode 131 are connected to conductors, and that these conductors are located inside the catheter 101. It is preferable that the handle portion 105 is located at the proximal end of the catheter 101. It is preferable that the conductors extend to the proximal end and are connected to a connector via the handle portion 105. It is preferable that the first electrode 111 and the second electrode 131 are electrically connected to external devices such as a power supply unit and an electrocardiogram display unit via the connector.

[0161] The power supply unit applies energy to the body's tissues. The power supply unit has a power source that applies voltage, and can supply the electrodes with the power necessary to perform various procedures by, for example, applying a pulse voltage between multiple electrodes or between an electrode and a counter electrode plate. The power supply is connected to the first electrode 111 and / or the second electrode 131 via a conductor.

[0162] The electrocardiogram display unit displays the intracardiac potential measured by the first electrode 111 and / or second electrode 131 of the catheter 101 as an intracardiac electrocardiogram. The catheter 101 may be connected to the electrocardiogram display unit via a power supply unit, or it may be connected to the electrocardiogram display unit without going through a power supply unit. An electrocardiograph can be used as an example of an electrocardiogram display unit.

[0163] The conductor only needs to be composed of at least a conductive material, and for example, iron wire, silver wire, stainless steel wire, copper wire, tungsten wire, nickel-titanium wire, etc. can be used. Preferably, the conductor contains a conductive material as a core material, and the core material is covered with an insulating material. As the insulating material, fluororesin (for example, PTFE, PFA, FEP, ETFE), polyolefin resin (for example, polyethylene or polypropylene), polyvinyl chloride resin, etc. can be used.

[0164] It is preferable that electrodes are arranged on the outer surface of the wire. This makes it easier to bring the electrodes into contact with body tissue. The electrodes may be placed on the outer surface of the wire, or a recess may be formed on the outer surface of the wire and the electrodes may be embedded in the recess. Electrode material may be printed on the outer surface of the wire. The wire may be inserted into the lumen of the tube, and the electrodes may be arranged on the tube (preferably on the outer surface of the tube). For the configuration of the tube, refer to the description of the shaft 102.

[0165] The number of first electrodes 111 in the proximal basket 121 may be greater than or less than the number of second electrodes 131 in the distal basket 141, or they may be the same number.

[0166] The catheter 101 preferably has a longitudinal direction and a circumferential direction. In this document, the case in which the longitudinal direction and circumferential direction of the catheter 101 coincide with the longitudinal direction x and circumferential direction z of the shaft 102 is given as an example, but these directions may be different from each other.

[0167] In one cross-section perpendicular to the longitudinal direction of the catheter 101, it is preferable that the number of electrodes arranged circumferentially for potential measurement is greater than the number of electrodes arranged circumferentially for ablation in another cross-section perpendicular to the longitudinal direction of the catheter 101. In particular, in the case of a catheter 101 used for pulsed-field ablation, it is sufficient to secure the number of electrodes necessary for electric field formation, while potential measurement at multiple locations contributes to identifying abnormal areas in the body, so it is preferable to set the number of electrodes in this manner. For example, if the electrodes of the distal basket 141 are for potential measurement and the electrodes of the proximal basket 121 are for ablation, it is preferable that the number of electrodes arranged circumferentially in one cross-section of the distal basket 141 perpendicular to the longitudinal direction is greater than the number of electrodes arranged circumferentially in one cross-section of the proximal basket 121 perpendicular to the longitudinal direction. Furthermore, if the electrodes of the proximal basket 121 are for potential measurement and the electrodes of the distal basket 141 are for cauterization, it is preferable that the number of electrodes arranged circumferentially in one cross-section of the proximal basket 121 in a direction perpendicular to the longitudinal direction is greater than the number of electrodes arranged circumferentially in one cross-section of the distal basket 141 in a direction perpendicular to the longitudinal direction.

[0168] The number of electrodes arranged circumferentially in one cross-section perpendicular to the longitudinal direction of the catheter 101 for potential measurement may be the same as the number of electrodes arranged circumferentially in another cross-section perpendicular to the longitudinal direction of the catheter 101 for cauterization. For example, the number of electrodes arranged circumferentially in one cross-section of the distal basket 141 perpendicular to the longitudinal direction may be the same as the number of electrodes arranged circumferentially in one cross-section of the proximal basket 121 perpendicular to the longitudinal direction.

[0169] Electrodes may be placed on all the wires in a single basket. Or, electrodes may be placed on only some of the wires among the multiple wires in a single basket.

[0170] A single wire may have only one electrode, or it may have multiple electrodes.

[0171] Preferably, the first wire 122 has a plurality of first electrodes 111 arranged along the direction of extension of the first wire 122. Preferably, the second wire 142 has a plurality of second electrodes 131 arranged along the direction of extension of the second wire 142.

[0172] The distal basket 141 is preferably located distal to the distal end 102a of the shaft 102. The distal basket 141 is preferably not joined to the shaft 102.

[0173] It is preferable that neither the proximal basket 121 nor the distal basket 141 is arranged to completely enclose the other.

[0174] As shown in Figures 14 to 20, the distal basket 141 may overlap a portion of the proximal basket 121 in the longitudinal direction x. Preferably, the distal basket 141 does not overlap the entire proximal basket 121 in the longitudinal direction x. This makes it possible to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is shorter than that of the catheter shown in Figure 21. In this document, the total length of the proximal basket 121 and the distal basket 141 means the length from the distal end 141a of the distal basket 141 to the proximal end 121b of the proximal basket 121 in the longitudinal direction x.

[0175] When we say that parts of the baskets overlap, we mean that they overlap for any length in the longitudinal direction x (for example, between 1 cm and 10 cm), not at any single point along the longitudinal direction x. This can also be rephrased as the distal end 121a of the proximal basket 121 being located distal to the proximal end 141b of the distal basket 141.

[0176] As a result of the distal basket 141 overlapping with a portion of the proximal basket 121 in the longitudinal direction x, the first wire 122 and the second wire 142 may intersect when the catheter 101 is viewed from the radial direction y.

[0177] As shown in Figure 21, the proximal basket 121 and the distal basket 141 may be arranged in series in the longitudinal direction x. That is, the proximal basket 121 and the distal basket 141 may be arranged without overlapping in the longitudinal direction x. This makes it possible to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is longer than that of the catheters shown in Figures 14 to 20.

[0178] The distal end 121a of the proximal basket 121 refers to the most distal position visible in a side view of the catheter 101, excluding any portion that is covered by other components and therefore not visible. The same applies to the proximal end 121b of the proximal basket 121, and the distal end 141a and proximal end 141b of the distal basket 141.

[0179] As shown in Figure 17, in the longitudinal direction x, it is preferable that the distal end 121a of the proximal basket 121 is located between the distal end 141a of the distal basket 141 and the maximum outer diameter position 141c. By positioning the distal end 121a in this manner, the two baskets are more likely to overlap over a wide area.

[0180] As shown in Figure 17, in the longitudinal direction x, it is preferable that the proximal end 141b of the distal basket 141 is located between the maximum outer diameter position 121c of the proximal basket 121 and the proximal end 121b. By positioning the proximal end 141b in this manner, the two baskets are more likely to overlap over a wide area.

[0181] As shown in Figure 20, it is preferable that in the longitudinal direction x, the distal end 121a of the proximal basket 121 is located between the proximal end 141b of the distal basket 141 and the maximum outer diameter position 141c of the distal basket 141. By positioning the proximal end 141b in this manner, it becomes easier to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is longer than that of the catheter shown in Figure 17, while overlapping the two baskets within an appropriate range.

[0182] As shown in Figure 20, in the longitudinal direction x, it is preferable that the proximal end 141b of the distal basket 141 is located between the maximum outer diameter position 121c of the proximal basket 121 and the distal end 121a of the proximal basket 121. By positioning the proximal end 141b in this manner, it becomes easier to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is longer than that of the catheter shown in Figure 17, while overlapping the two baskets within an appropriate range.

[0183] Although not shown in the figures, in the longitudinal direction x, the distal end 121a of the proximal basket 121 is located between the distal end 141a of the distal basket 141 and the maximum outer diameter position 141c, and the proximal end 141b of the distal basket 141 may be located between the maximum outer diameter position 121c of the proximal basket 121 and the distal end 121a. Also, in the longitudinal direction x, the distal end 121a of the proximal basket 121 is located between the proximal end 141b of the distal basket 141 and the maximum outer diameter position 141c, and the proximal end 141b of the distal basket 141 may be located between the maximum outer diameter position 121c of the proximal basket 121 and the proximal end 121b.

[0184] As shown in Figure 21, it is preferable that in the longitudinal direction x, the distal end 121a of the proximal basket 121 is located more proximal to the proximal end 141a of the distal basket 141. This makes it possible to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is longer than that of the catheters shown in Figures 14 to 20.

[0185] As shown in Figure 24, it is preferable that the proximal end 141b of the distal basket 141 is in the same position as the proximal end 121b of the proximal basket 121 in the longitudinal direction x. By positioning the proximal end 141b in this way, the entire proximal basket 121 can be made to overlap with the distal basket 141.

[0186] As shown in Figures 17 and 20, when both the proximal basket 121 and the distal basket 141 are fully expanded, the catheter 101 may have, in the longitudinal direction x, a first portion 151 where the proximal basket 121 and the distal basket 141 overlap, and a second portion 152 of the proximal basket 121 that does not overlap with the distal basket 141.

[0187] As shown in Figure 17, when both the distal basket 141 and the proximal basket 121 are fully expanded, the length of the first part 151 may be longer than the length of the second part 152. Here, the length of the first part 151 and the length of the second part 152 refer to the length in the longitudinal direction x.

[0188] As shown in Figure 20, when both the distal basket 141 and the proximal basket 121 are fully expanded, the length of the first portion 151 may be shorter than the length of the second portion 152.

[0189] In Figures 17, 20, and 24, with both the proximal basket 121 and the distal basket 141 fully expanded, the catheter 101 has a third portion 153 in the longitudinal direction x of the distal basket 141 that does not overlap with the proximal basket 121. As shown in Figure 17, it is preferable that the third portion 153 is shorter than the first portion 151 in the longitudinal direction x. As shown in Figure 20, the third portion 153 may be longer than the first portion 151 in the longitudinal direction x. The third portion 153 may be longer than the second portion 152, or shorter than the second portion 152.

[0190] As shown in Figure 24, when both the proximal basket 121 and the distal basket 141 are fully expanded, the catheter 101 may have the entire proximal basket 121 overlapping the distal basket 141 in the longitudinal direction x. That is, the catheter 101 may have a first portion 151 and a third portion 153, but may not have a second portion 152.

[0191] As shown in Figures 14 to 16, it is preferable that the handle portion 105 has a first connector 181 that is connected to the cauterizing electrode 191 but not to the potential measuring electrode 192 and is connected to the power supply unit, and a second connector 182 that is connected to the potential measuring electrode 192 but not to the cauterizing electrode 191 and is connected to the electrocardiogram display unit. In Figures 14 to 16, the handle portion 105 includes a first handle 106 connected to the proximal part of the shaft 102, and the first handle 106 is provided with the first connector 181 and the second connector 182.

[0192] As shown in Figure 18, the first electrode 111 is preferably an electrode 191 for cauterization, and the proximal basket 121 preferably does not have an electrode for potential measurement. This allows the first electrode 111 to be used as an electrode exclusively for cauterization. The second electrode 131 is preferably an electrode 192 for potential measurement, and the distal basket 141 preferably does not have an electrode for cauterization. This allows the second electrode 131 to be used as an electrode exclusively for potential measurement. Since the first electrode 111 of the proximal basket 121 is for cauterization and the second electrode 131 of the distal basket 141 is for potential measurement, the procedure can be performed efficiently by first measuring the potential using the second electrode 131 of the distal basket 141, which is introduced into the body first, and then advancing the catheter 101 distally, allowing cauterization to be performed with the first electrode 111 of the proximal basket 121, which is inserted following. Note that mapping may also be performed using the electrode for potential measurement, and the same applies in the following description.

[0193] When the first electrode 111 is an electrode 191 for cauterization and the second electrode 131 is an electrode 192 for potential measurement, it is preferable that the first electrode 111 is connected to the first connector 181 and the second electrode 131 is connected to the second connector 182.

[0194] It is preferable that all first electrodes 111 of the proximal basket 121 are cauterizing electrodes 191. It is preferable that all second electrodes 131 of the distal basket 141 are potential measuring electrodes 192. It is preferable that current is passed between the multiple first electrodes 111 of the proximal basket 121.

[0195] As another example, as shown in Figure 19, it is preferable that the second electrode 131 is an electrode 191 for cauterization, and that the distal basket 141 does not have an electrode for potential measurement. This allows the second electrode 131 to be used as an electrode exclusively for cauterization. In that case, it is preferable that the first electrode 111 is an electrode 192 for potential measurement, and that the proximal basket 121 does not have an electrode for cauterization. This allows the first electrode 111 to be used as an electrode exclusively for potential measurement. In this example, it is preferable that the first electrode 111 is connected to the second connector 182, and the second electrode 131 is connected to the first connector 181. Since the first electrode 111 in the proximal basket is for potential measurement and the second electrode 131 in the distal basket is for cauterization, it is possible to perform the procedure efficiently by measuring the potential with the first electrode 111 on the front side and then performing cauterization with the second electrode 131 on the back side.

[0196] It is preferable that all the second electrodes 131 of the distal basket 141 are cauterizing electrodes 191. It is preferable that all the first electrodes 111 of the proximal basket 121 are potential measuring electrodes 192. It is preferable that current is passed between the multiple second electrodes 131 of the distal basket 141.

[0197] It is preferable that no current is passed between the first electrode 111 of the proximal basket 121 and the second electrode 131 of the distal basket 141.

[0198] Next, we will describe the mechanism for expanding the basket.

[0199] As shown in Figures 18 to 19, if the shaft 102 has a lumen 102c extending in the longitudinal direction x, it is preferable that the catheter 101 extends in the longitudinal direction x, is connected to at least one of the proximal basket 121 and the distal basket 141, is inserted into the lumen 102c of the shaft 102, and has a traction member 161 that is movable in the longitudinal direction x relative to the shaft 102. The traction member 161 transmits the operation on the proximal side to the proximal basket 121 and / or the distal basket 141. It is preferable that the proximal basket 121 and the distal basket 141 expand as the traction member 161 moves proximal to the shaft 102. Figures 18 to 19 show an example in which the traction member 161 is connected to the distal basket 141.

[0200] In Figures 14 to 16, the handle portion 105 has a first handle 106 connected to the proximal part of the shaft 102 and a second handle 107 connected to the proximal part of the traction member 161. As shown in Figures 18 to 19, it is preferable that the first handle 106 has a hollow portion 106c inside, and it is preferable that the traction member 161 is inserted through the hollow portion 106c.

[0201] The traction member 161 preferably has an elongated shape. The traction member 161 may be a single wire or may have a structure consisting of multiple linear objects. The traction member 161 preferably extends along the longitudinal direction x of the shaft 102. The shaft 102 may have a distal opening and a proximal opening that communicate with the lumen 102c. As can be seen from Figures 18 to 19, the traction member 161 preferably extends from the distal opening of the shaft 102. The traction member 161 preferably extends from the proximal side of the first handle 106. The proximal opening of the shaft 102 preferably communicates with the hollow portion 106c of the first handle 106.

[0202] The traction member 161 may have a solid shape or a hollow shape. A cylindrical body can be an example of a hollow traction member 161. The traction member 161 may be a solid metal wire or resin wire covered by a coiled cylindrical body made of metal and / or synthetic resin.

[0203] The traction member 161 can be made of, for example, metals such as stainless steel, carbon steel, and nickel-titanium alloy, or synthetic resins such as polyamide resin (e.g., nylon), polyolefin resin (e.g., polyethylene and polypropylene), polyester resin (e.g., PET), aromatic polyetherketone resin (e.g., PEEK), polyimide resin, and fluororesin (e.g., PTFE, PFA, FEP, ETFE).

[0204] As shown in Figures 18 to 19, the catheter 101 may have a first connection portion 171 to which the distal end of the traction member 161 and the distal end of the distal basket 141 are connected. With this configuration, the distal basket 141 can be expanded or contracted by moving the traction member 161 distally or proximal. As shown in Figure 18, it is preferable that the distal end of the traction member 161 and the plurality of second wires 142 constituting the distal basket 141 are connected to each other at the first connection portion 171.

[0205] The connection method at the first connection part 171 can include methods such as welding, silver brazing, soldering, crimping, bonding with adhesive, engagement, fitting, linking, bundling, and other physical fixing methods, or combinations thereof. At least one of these methods can also be used when connecting the second connection part 172, third connection part 173, fourth connection part 174, and at least two other elements, as described later. Here, "connection" includes both forms in which at least two elements are directly connected and forms in which at least two elements are indirectly connected via one or more other elements.

[0206] In the first connection section 171, the traction member 161 and the second wire 142 may or may not be in contact with each other.

[0207] As shown in Figures 18 to 19, the first connection portion 171 may be connected to the traction member 161 and a plurality of second wires 142 by a tip 164. The shape of the tip 164 is not particularly limited, but the tip 164 may have one or more insertion openings in at least a portion of the longitudinal direction x of the shaft 102 into which the distal ends of the plurality of second wires 142 and / or the traction member 161 are inserted. For example, in Figure 18, the tip 164 has a first insertion opening 164m into which the distal end of the traction member 161 is inserted, and a second insertion opening 164n into which the distal ends of the plurality of second wires 142 are inserted.

[0208] In the radial direction y of the shaft 102, it is preferable that the second insertion opening 164n is positioned outward from the first insertion opening 164m. In the radial direction y of the shaft 102, it is preferable that the first insertion opening 164m is positioned so as to coincide with the central axis in the longitudinal direction x of the shaft 102.

[0209] A recess provided on the outer side of the tip 164 in the radial direction y may be the second insertion opening 164n. The tip 164 may have an outer cylinder portion and an inner cylinder portion, and the space between the outer cylinder portion and the inner cylinder portion may be the second insertion opening 164n. One or more second insertion openings 164n may be provided.

[0210] The tip 164 can be made from the same material as at least one of the first wire 122, the second wire 142, the traction member 161, and the shaft 102.

[0211] As shown in Figures 18 to 19, the catheter 101 may have a cylindrical member 165 positioned distal to the distal end of the shaft 102 and proximal to the first connection portion 171, with a traction member 161 inserted into the lumen 165c of the cylindrical member 165, and a second connection portion 172 to which the proximal end of the distal basket 141 is connected to the cylindrical member 165. With this configuration, when the traction member 161 moves distally or proximal, the cylindrical member 165 moves relative to the traction member 161, and the distance from the first connection portion 171 to the second connection portion 172 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the distal basket 141.

[0212] The cylindrical member 165 is a member for binding the first wire 122 of the proximal basket 121 and the second wire 142 of the distal basket 141. The cylindrical member 165 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 165 is movable distally or proximal relative to the traction member 161. It is preferable that the cylindrical member 165 is not fixed to the traction member 161.

[0213] The cylindrical member 165 can be made from the same material as at least one of the first wire 122, the second wire 142, the traction member 161, the shaft 102, and the tip 164.

[0214] As shown in Figure 18, it is preferable that a first insertion opening 165m is provided on the outer radial y portion of the cylindrical member 165 into which the proximal end of the second wire 142 of the distal basket 141 is inserted. The second wire 142 may be inserted into the first insertion opening 165m and the cylindrical member 165 may be crimped from the outside. The first insertion opening 165m may be a recess provided on the outer radial y portion of the cylindrical member 165. The cylindrical member 165 may have an outer cylinder and an inner cylinder, and the space between the outer cylinder and the inner cylinder may be the first insertion opening 165m. It is preferable that the first insertion opening 165m is located radially y outward from the lumen 165c of the cylindrical member 165.

[0215] Although not shown in the diagram, the second wire 142 can be connected to any part of the cylindrical member 165, as long as it does not obstruct the movement of the traction member 161. For example, the second connection portion 172 may be formed by joining the second wire 142 to the outer surface of the cylindrical member 165.

[0216] As shown in Figures 18 to 19, the catheter 101 may have a third connection portion 173 to which the distal end of the proximal basket 121 and the cylindrical member 165 are connected. With this configuration, the proximal basket 121 can be expanded or contracted by moving the traction member 161 distally or proximally. Preferably, at the third connection portion 173, the distal end of the traction member 161 and the plurality of first wires 122 constituting the proximal basket 121 are connected to each other.

[0217] In the third connection section 173, the distal end of the proximal basket 121 can be connected to the cylindrical member 165 in the same manner as in the second connection section 172, except that the part of the wire being connected is either the distal or proximal end. Figure 18 shows an example in which the cylindrical member 165 has a second insertion opening 165n into which the distal end of the proximal basket 121 is inserted.

[0218] In the cylindrical member 165, it is preferable that the second insertion opening 165n is located distal to the first insertion opening 165m. By arranging the first insertion opening 165m and the second insertion opening 165n in this way, the two baskets are more likely to overlap over a wide area.

[0219] As shown in Figures 18 to 19, the catheter 101 may have a fourth connection portion 174 to which the proximal end of the proximal basket 121 and the distal end of the shaft 102 are connected. With this configuration, as the traction member 161 moves distally or proximal, the proximal basket 121 curves and / or bends, and the distance from the third connection portion 173 to the fourth connection portion 174 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the proximal basket 121. Preferably, the first wire 122 and the shaft 102 constituting the proximal basket 121 are connected to each other at the fourth connection portion 174.

[0220] In the fourth connection section 174, the proximal end of the proximal basket 121 can be connected to the distal end of the shaft 102 in the same manner as in the second connection section 172. Figure 18 shows an example in which the shaft 102 has an insertion opening 102f into which the proximal end of the first wire 122 is inserted. It is preferable that the multiple first wires 122 are not fixed to the traction member 161 in the fourth connection section 174.

[0221] As shown in Figure 18, in the longitudinal direction x, the distal end of the insertion port 102f of the shaft 102 may be at the same position as the distal end of the lumen 102c of the shaft 102. In the longitudinal direction x, the distal end of the insertion port 102f of the shaft 102 may be located proximal to the distal end of the lumen 102c. In the radial direction y, it is preferable that the insertion port 102f is located outward from the lumen 102c.

[0222] Although not shown in the figures, the first wire 122 and the cylindrical member 165 may be in contact when the proximal basket 121 is in its most expanded state, and the inner surface of the proximal basket 121 in the radial direction y may be in contact with the proximal end of the cylindrical member 165.

[0223] As can be seen from Figure 18, it is preferable that the cylindrical member 165 and the tip 164 are in contact when the distal basket 141 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 165 and the proximal end of the tip 164 are in contact.

[0224] As can be seen from Figure 17, it is preferable that the cylindrical member 165 and the second wire 142 are in contact when the distal basket 141 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 165 and the inner surface of the distal basket 141 in the radial direction y are in contact.

[0225] Although not shown in the diagram, when the proximal basket 121 is in its most expanded state, the cylindrical member 165 and the shaft 102 may be in contact, or the proximal end of the cylindrical member 165 and the distal end of the shaft 102 may be in contact.

[0226] As shown in Figures 14 to 20, it is preferable that the second connection portion 172 is located proximal to the third connection portion 173 in the longitudinal direction x. This makes it possible to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is shorter than that of the catheter shown in Figure 21.

[0227] As shown in Figure 21, in the longitudinal direction x, the second connection portion 172 may be located distal to the third connection portion 173. This makes it possible to obtain a catheter in which the total length of the proximal basket 121 and the distal basket 141 is longer than that of the catheters shown in Figures 14 to 20.

[0228] As can be seen from Figure 23, it is preferable that the distal basket 141 and the proximal basket 121 move relative to each other when both are in their most expanded state. Since the position of the proximal basket 121 relative to the distal basket 141 can be changed, the electrode position can be adjusted to suit the shape of the patient's pulmonary veins.

[0229] In the catheter 101 shown in Figures 21 and 22, an example is shown in which the distal end of the proximal basket 121 and the proximal end of the distal basket 141 are connected to the same cylindrical member 165. However, in order to configure the two baskets to move relative to each other, as shown in Figure 23, the distal end of the proximal basket 121 may be connected to the first cylindrical member 168 and the proximal end of the distal basket 141 may be connected to the second cylindrical member 169. In that case, it is preferable that the second cylindrical member 169 is inserted through the lumen of the first cylindrical member 168, a traction member 161 is inserted through the lumen of the second cylindrical member 169, and that the first cylindrical member 168 and the second cylindrical member 169 are each movable in the longitudinal direction of the traction member 161. It is preferable that the second cylindrical member 169 extends to the proximal part of the catheter 101 (for example, the handle part 105) or is connected to a long member that extends to the proximal part of the catheter 101 (for example, the handle part 105). By moving the second cylindrical member 169 or the elongated member relative to the first cylindrical member 168, the distal basket 141 and the proximal basket 121 can be moved relative to each other.

[0230] For further details regarding the configuration of the first cylindrical member 168 and the second cylindrical member 169, please refer to the description of the cylindrical member 165.

[0231] With reference to Figures 24 and 25, other basket expansion mechanisms will be described. If the shaft 102 has a lumen 102c extending in the longitudinal direction x, the catheter 101 may further include a traction member 161 that extends in the longitudinal direction x, is connected to at least one of the proximal basket 121 and the distal basket 141, is inserted into the lumen 102c of the shaft 102 and is movable in the longitudinal direction x relative to the shaft 102, a first connection portion 171 to which the distal end of the traction member 161 and the distal end of the distal basket 141 are connected, and a cylindrical member 166 disposed distal to the distal end of the shaft 102 and proximal to the first connection portion 171, the traction member 161 being inserted into the lumen of the cylindrical member 166 and the cylindrical member 166 being movable in the longitudinal direction x of the traction member 161. In this case, it is preferable that the distal end of the proximal basket 121 is connected to the cylindrical member 166, and the proximal end of the distal basket 141 is connected to the proximal end of the proximal basket 121 and the distal end of the shaft 102. With this configuration, by moving the traction member 161 towards the proximal side, the proximal basket 121 and the distal basket 141 bend or curve, and the distance from the first connection part 171 to the distal end of the shaft 102 in the longitudinal direction x, and the distance from the distal end of the proximal basket 121 to the distal end of the shaft 102 in the longitudinal direction x, are shortened. In this way, by pulling the traction member 161, the proximal basket 121 and the distal basket 141 can be expanded together or sequentially.

[0232] For the configuration of the first connection part 171 shown in Figures 24 to 25, please refer to the explanation of the first connection part 171 shown in Figures 18 to 19.

[0233] The cylindrical member 166 is a member for binding the first wire 122 of the proximal basket 121. The cylindrical member 166 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 166 is movable distally or proximal to the traction member 161. It is preferable that the cylindrical member 166 is not fixed to the traction member 161.

[0234] The cylindrical member 166 can be made of the same material as at least one of the first wire 122, the second wire 142, the traction member 161, the shaft 102, and the tip 164.

[0235] For information on how to connect the distal end of the proximal basket 121 to the cylindrical member 166, please refer to the explanation of the third connection part 173 shown in Figures 18 to 19.

[0236] For information on how to connect the proximal end of the distal basket 141, the proximal end of the proximal basket 121, and the distal end of the shaft 102, please refer to the description of the fourth connection part 174 shown in Figures 18 to 19.

[0237] Referring to Figures 26 and 27, further expansion mechanisms of the basket will be described. The shaft 102 has a lumen 102c extending in the longitudinal direction x, and the catheter 101 extends in the longitudinal direction x and is connected to at least one of the proximal basket 121 and the distal basket 141, is inserted into the lumen 102c of the shaft 102, and may further have a traction member 161 that is movable in the longitudinal direction x relative to the shaft 102, and a first connection part 171 to which the distal end of the traction member 161 and the distal end of the distal basket 141 are connected. In this case, it is preferable that the distal end of the proximal basket 121 and the longitudinal middle part of the traction member 161 are connected, and the proximal end of the distal basket 141 and the proximal end of the proximal basket 121 and the distal end of the shaft 102 are connected. Since the distal end of the proximal basket 121 and the middle of the longitudinal direction of the traction member 161 are connected, the distance from the first connection part 171 to the distal end of the proximal basket 121 in the longitudinal direction x does not change even when the traction member 161 is moved in the longitudinal direction x. On the other hand, in the longitudinal direction x, the distance from the distal end of the proximal basket 121 to the distal end of the shaft 102 changes depending on the degree to which the traction member 161 is pulled proximal. Specifically, as the traction member 161 moves proximal, the proximal basket 121 and the distal basket 141 curve and / or bend, and the distance from the first connection part 171 to the distal end of the shaft 102, and the distance from the distal end of the proximal basket 121 to the distal end of the shaft 102 in the longitudinal direction x, become shorter. In this way, by pulling the traction member 161, the proximal basket 121 and the distal basket 141 can be expanded together or sequentially.

[0238] One end of the traction member 161 refers to a range of 5% of the total length of the traction member 161, the other end of the traction member 161 refers to a range of 5% of the total length of the traction member 161, and the middle section of the traction member 161 refers to the remaining 90% of the length of the traction member 161 excluding the one end and the other end. Preferably, the distal end of the proximal basket 121 is connected to the distal section of the middle section of the traction member 161 when the total length of the middle section is divided into three equal parts.

[0239] It is preferable that the distal end of the first wire 122 is fixed to the traction member 161, and more preferably that it is joined to it. This causes the proximal basket 121 to expand as the distance from the distal end of the first wire 122 to the distal end of the shaft 102 shortens when the traction member 161 moves proximal. Also, when the traction member 161 moves proximal, the distance from the first connection part 171 to the distal end of the shaft 102 shortens, causing the distal basket 141 to expand.

[0240] It is preferable that the distal end of the first wire 122 is fixed to the middle part of the traction member 161 and does not move. It is preferable that the distal end of the first wire 122 does not move relative to the longitudinal direction of the traction member 161.

[0241] Figure 24 shows an example in which the distal end of the first wire 122 is bound by a cylindrical member 167, and the inner wall defining the lumen of the cylindrical member 167 is fixed to the outer surface of the middle portion of the traction member 161. However, the method of connecting the distal end of the proximal basket 121 and the middle portion of the traction member 161 is not limited to this. As a method of connecting the proximal basket 121 and the traction member 161, at least one of the methods listed for connection at the first connection portion 171 can be used.

[0242] For details regarding the configuration of the cylindrical member 167, please refer to the description of the cylindrical members 165 and 166.

[0243] As shown in Figure 28, when viewing the catheter 101 from distal to proximal, it is preferable that the first wire 122 and the second wire 142 are arranged alternately in the circumferential direction. It is preferable that the first wire 122 and the second wire 142 are arranged alternately in the circumferential direction when both the distal basket 141 and the proximal basket 121 are at their most expanded state. It is also preferable that the first wire 122 and the second wire 142 are arranged alternately in the circumferential direction when both the distal basket 141 and the proximal basket 121 are at their most contracted state. By arranging the first wire 122 and the second wire 142 in this way, contact between the electrode for cauterization and the electrode for potential measurement can be prevented.

[0244] As shown in Figure 29, it is preferable that the first wire 122 and the second wire 142 overlap when the catheter 101 is viewed from the distal to the proximal end. In this case, a portion of the first wire 122 and a portion of the second wire 142 may overlap each other in the circumferential direction, or the entire first wire 122 may overlap with the second wire 142. This prevents misalignment between the potential measurement position and the cauterization position, allowing for efficient cauterization.

[0245] As shown in Figure 28, it is preferable that the first wire 122 and the second wire 142 are separated when both the distal basket 141 and the proximal basket 121 are at their most expanded state. It is also preferable that the first wire 122 and the second wire 142 are separated in the first portion when both the distal basket 141 and the proximal basket 121 are at their most expanded state. It is preferable that the first wire 122 and the second wire 142 are separated in the second portion 152 when both the distal basket 141 and the proximal basket 121 are at their most expanded state. When both the distal basket 141 and the proximal basket 121 are at their most expanded state and are each divided into an outer portion and an inner portion in the radial direction y, it is preferable that the outer portion of the distal basket 141 and the outer portion of the proximal basket 121 are separated.

[0246] As can be seen from Figures 14 and 15, it is preferable that the first wire 122 and the second wire 142 are in contact when at least one of the distal basket 141 and the proximal basket 121 is at its most contracted state. It is more preferable that the first wire 122 and the second wire 142, which are adjacent to each other in the circumferential direction, are in contact when at least one of the distal basket 141 and the proximal basket 121 is at its most contracted state. It is preferable that the first wire 122 and the second wire 142 are in contact at the first portion 151 when at least one of the distal basket 141 and the proximal basket 121 is at its most contracted state. It is preferable that the first wire 122 and the second wire 142 are separated at the second portion 152 when at least one of the distal basket 141 and the proximal basket 121 is at its most contracted state.

[0247] In the first part 151, electrodes may be provided in the distal basket 141 and the proximal basket 121, respectively.

[0248] Although not shown in the diagram, when both the distal basket 141 and the proximal basket 121 are in their most expanded state, an electrode for cauterization may be placed in the second portion 152 of the proximal basket 121, and an electrode for potential measurement may be placed in the third portion 153 of the distal basket 141.

[0249] Although not shown in the diagram, when both the distal basket 141 and the proximal basket 121 are in their most expanded state, electrodes for potential measurement may be placed in the second portion 152 of the proximal basket 121, and electrodes for cauterization may be placed in the third portion 153 of the distal basket 141.

[0250] It is preferable that the cauterizing electrode is positioned proximal to the portion of the first wire 122 where the first wire 122 and the second wire 142 intersect.

[0251] It is preferable that the cauterizing electrode is positioned distal to the portion of the first wire 122 where the first wire 122 and the second wire 142 intersect.

[0252] It is preferable that the cauterizing electrode is positioned on the side of the second wire 142 that is proximal to the portion where the first wire 122 and the second wire 142 intersect.

[0253] It is preferable that the cauterizing electrode is positioned distal to the portion of the second wire 142 where the first wire 122 and the second wire 142 intersect.

[0254] An electrode for cauterization may be placed in the portion of the first wire 122 where the first wire 122 and the second wire 142 intersect.

[0255] An electrode for cauterization may be placed in the portion of the second wire 142 where the first wire 122 and the second wire 142 intersect.

[0256] As shown in Figure 17, when both the distal basket 141 and the proximal basket 121 are in their most expanded state, it is preferable that the maximum outer diameter of the proximal basket 121 is larger than the maximum outer diameter of the distal basket 141. This makes it easier to bring the distal basket 141 into contact with the inner wall of the pulmonary vein and the proximal basket 121 into contact with the antrum of the pulmonary vein.

[0257] When both the distal basket 141 and the proximal basket 121 are fully expanded, the maximum outer diameter of the proximal basket 121 may be smaller than the maximum outer diameter of the distal basket 141. This makes it easier to use when you want to firmly fix the catheter 101 inside the body with the distal basket 141, or when the antrum of the pulmonary veins is raised due to a lesion or the like, and a smaller outer diameter of the proximal basket 121 is preferable.

[0258] The catheter according to the third embodiment comprises a shaft having a longitudinal direction, a proximal basket disposed at the distal end of the shaft, and a distal basket whose longitudinal direction at least a portion is disposed distal to the proximal basket, and an expandable portion having electrodes in at least one of the proximal basket and the distal basket, the essence of which is that the expandable portion takes the form of a first state in which both the distal basket and the proximal basket are contracted, and a second state in which the distal basket is expanded and the proximal basket is contracted. With the above catheter, the distal basket expands in the second state and comes into contact with the body tissue, so the catheter can be fixed in the body and it is easier to perform potential measurement and cauterization using electrodes.

[0259] A catheter according to a third embodiment of the present disclosure will be described with reference to Figures 30 to 44. Figure 30 is a side view of the catheter according to the third embodiment of the present disclosure, showing the first state. Figure 31 is a side view of the catheter according to the third embodiment of the present disclosure, showing the second state. Figure 32 is a side view of the catheter according to the third embodiment of the present disclosure, showing the third state. Figure 33 is an enlarged side view of the distal side of the catheter shown in Figure 32. Figure 34 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 33. Figure 35 is a cross-sectional view (partial side view) showing a modified example of the catheter shown in Figure 34. Figure 36 is a side view showing a modified example of the catheter shown in Figure 33. Figure 37 is a side view showing a modified example of the catheter shown in Figure 33. Figure 38 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 37. Figure 39 is a side view showing a modified example of the catheter shown in Figure 37. Figure 40 is a side view showing another modified example of the catheter shown in Figure 33. Figure 41 is a cross-sectional view (partially a side view) showing the connection state of each component on the distal side of the catheter shown in Figure 40. Figure 42 is a cross-sectional view (partially a side view) showing another modified example of the catheter shown in Figure 33. Figures 43 to 44 are schematic diagrams showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side of a catheter according to the third embodiment of this disclosure. Note that some wires are omitted in the diagrams showing the connection state of each component. As shown in Figures 30 to 34, the catheter 201 comprises a shaft 202 and an expansion section 220 having a proximal basket 221 and a distal basket 241.

[0260] As shown in Figures 30 to 32, the shaft 202 has a longitudinal direction x. As shown in Figure 34, the shaft 202 preferably has a distal end 202a and a proximal end 202b in the longitudinal direction x. The proximal side of the shaft 202 refers to the direction toward the user or operator's hand relative to the longitudinal direction x of the shaft 202, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. In each drawing, the right side of the figure is the proximal side, and the left side of the figure is the distal side. The shaft 202 preferably has a radial direction y and a circumferential direction z. The radial direction y refers to the radial direction of the shaft 202, in which case inward refers to the direction toward the center of the longitudinal axis of the shaft 202, and outward refers to the direction extending radially from the center of the longitudinal axis on the opposite side from inward. The circumferential direction z refers to the direction around the longitudinal axis of the shaft 202, i.e., the direction along the outer circumference of the shaft 202.

[0261] The shaft 202 can be composed of one or more members. Examples of the shaft 202 include a resin tube; a metal tube; a hollow body formed by arranging wires in a predetermined pattern; a hollow body with at least one of its inner or outer surfaces coated with resin; or a combination thereof, for example, these connected in the longitudinal direction x. The resin tube can be manufactured, for example, by extrusion molding. Examples of hollow bodies formed by arranging wires in a predetermined pattern include cylindrical bodies having a mesh structure by simply crossing or weaving wires, and coils in which wires are wound. The wires may be one or more single wires or one or more stranded wires. The type of mesh structure is not particularly limited, nor are the number of turns or density of the coils. The mesh structure or coil may be formed at a constant density over the entire longitudinal direction x of the shaft 202, or it may be formed so that the density differs depending on the position in the longitudinal direction x. To increase the flexibility of the metal tube, notches or grooves may be formed on the outer surface of the metal tube. The shape of the cuts and grooves can be straight, arcuate, annular, spiral, or a combination of these.

[0262] The shaft 202 preferably has one or more lumens, and more preferably has only one. The shaft 202 is preferably a single-lumen tube.

[0263] The shaft 202 is preferably flexible and elastic. The material constituting the shaft 202 is preferably resin, metal, or a combination of resin and metal. Using resin makes it easier to impart flexibility and elasticity to the shaft 202. Using metal can improve the ease of insertion of the catheter 201 into the vascular lumen.

[0264] The shaft 202 may have a single-layer structure or a multi-layer structure. If the shaft 202 has a multi-layer structure, for example, a reinforcing material such as a wire made of metal such as stainless steel, carbon steel, or nickel-titanium alloy can be provided as an intermediate layer of the resin tube that constitutes the shaft 202.

[0265] Examples of resins that make up the shaft 202 include polyamide resins such as polyamide and polyamide elastomer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyphenylene sulfide resin, polystyrene resin, fluororesin, vinyl chloride resin, silicone resin, natural rubber, synthetic rubber, and polyimide. These may be used individually or in combination of two or more. Examples of polyamides include nylon 12 and nylon 11. Examples of polyamide elastomers include polyether ester amide elastomer and polyamide ether elastomer.

[0266] Examples of metals that make up the shaft 202 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, Ni-Ti alloy, and Co-Cr alloy. These may be used individually or in combination of two or more.

[0267] As shown in Figures 30 to 34, the catheter 201 has a proximal basket 221 located at the distal end of the shaft 202, and a distal basket 241 located distal to the proximal basket 221 in the longitudinal direction x, and at least one of the proximal basket 221 and the distal basket 241 is provided with an expansion portion 220 having electrodes. In the catheter 201, the proximal basket 221 and the distal basket 241 exist independently of each other. Hereinafter, for simplicity, both or one of the proximal basket 221 and the distal basket 241 may be referred to as "baskets".

[0268] The basket is capable of expanding and contracting in the radial direction y. Preferably, the basket deflates and reduces in diameter when not subjected to external forces other than gravity, and expands in diameter when subjected to external forces other than gravity. Preferably, the basket has a shape that is convex outward in the radial direction y when it has its maximum outer diameter.

[0269] The basket preferably has a radial and a circumferential direction. In this document, the case in which the radial and circumferential directions of the basket coincide with the radial direction y and circumferential direction z of the shaft 202 is given as an example, but these directions may be different from each other.

[0270] The expandable section 220 can take two states: a first state in which both the distal basket 241 and the proximal basket 221 are contracted, as shown in Figure 30, and a second state in which the distal basket 241 is expanded and the proximal basket 221 is contracted, as shown in Figure 31. The contracted state refers to a state in which the basket has not yet begun to expand, and the outer diameter of the basket is equal to its minimum outer diameter. The expanded state refers to a state in which the basket has not contracted, and the outer diameter of the basket is greater than its minimum outer diameter. The expanded state also includes a state in which the basket is expanded to its maximum outer diameter. With the above catheter, the catheter 201 can be inserted into the body because it is reduced in diameter in the first state. In the second state, the distal basket 241 expands and comes into contact with the body tissue, so the catheter 201 can be fixed in the body by the distal basket 241. In the second state, displacement of the catheter 201 within the body can be prevented, making it easier to perform procedures such as potential measurement and ablation using electrodes on at least one of the distal basket 241 and the proximal basket 221.

[0271] Since the expansion section 220 can take on a second state, it is preferable that the proximal basket 221 and the distal basket 241 can each be expanded independently. That is, it is preferable that the proximal basket 221 and the distal basket 241 are configured to reach their maximum outer diameter at different times.

[0272] The expansion of the proximal basket 221 and the distal basket 241 may be synchronized. For example, it is preferable that the distal basket 241 expands to its maximum outer diameter when the user operates the handle portion 205 or the traction member 261, which will be described later, followed by the proximal basket 221 expanding to its maximum outer diameter.

[0273] The catheter 201 should be configured such that the distal basket 241 expands before the proximal basket 221 when the expansion section 220 transitions from the first state to the second state. In other words, it is preferable that the proximal basket 221 begins to expand after the distal basket 241 has begun to expand as a result of the user's operation on the proximal side.

[0274] The basket preferably has multiple wires. The wires preferably have elasticity and / or flexibility. The elastic wires preferably have a curved shape and / or a bent shape. When an external force is applied, the wires preferably bend and / or curve so as to be convex outward in the radial direction y.

[0275] The wire is preferably a single-strand or stranded linear member. The shape of the cross-section perpendicular to the longitudinal direction of the single-strand wire may be, for example, circular, elliptical, polygonal, a part thereof, or a combination thereof, or it may be completely amorphous. Alternatively, it may be a shape with rounded corners.

[0276] It is preferable that a basket is formed by arranging multiple wires at equal or unequal intervals around the longitudinal axis of the shaft 202. One wire may be arranged so that its circumferential position does not change from the distal to the proximal side of the shaft 202, or one wire may be arranged spirally around the longitudinal axis of the shaft 202. The shape of the basket can be changed by adjusting the shape and arrangement of each wire.

[0277] A basket may be formed by connecting the distal ends of multiple wires to each other, and connecting the proximal ends of multiple wires to each other. Preferably, the distal and / or proximal ends of multiple wires are tied together.

[0278] The wire is preferably made of a metal or resin capable of maintaining its shape, and more preferably made of a shape memory alloy or shape memory resin. As the material for the wire, at least one of the metals and / or resins that make up the shaft 202 can be used. In particular, the wire is preferably made of a single or stranded metal wire, and more preferably a metal wire made of a Ni-Ti alloy.

[0279] The first wire 222 of the proximal basket 221 and the second wire 242 of the distal basket 241 may be made of the same material or of different materials.

[0280] There is no limit to the number of wires a single basket may have, but for example, it may be three or more, four or more, five or more, six or more, eight or more, ten or more, or twenty or fewer, or fifteen or fewer.

[0281] The proximal basket 221 preferably has a plurality of first wires 222 arranged in the circumferential direction. The distal basket 241 preferably has a plurality of second wires 242 arranged in the circumferential direction.

[0282] It is preferable that the first wire 222 and the second wire 242 are provided independently. It is preferable that the first wire 222 and the second wire 242 are not joined together. It is preferable that the first wire 222 and the second wire 242 are not connected. By separating the first wire 222 and the second wire 242 in this way, it becomes easier to give each basket a shape suitable for it, and it becomes easier to expand each basket independently.

[0283] In the expansion section 220, at least one of the proximal basket 221 and the distal basket 241 has electrodes. As shown in Figures 30 to 34, it is preferable that the proximal basket 221 has multiple electrodes 211. It is preferable that the distal basket 241 has multiple electrodes 231. Because the expansion section 220 has multiple baskets, and each basket has electrodes, different functions can be assigned to each basket. For example, one basket can be used to fix the catheter 201 in the body or to measure potential, while the electrodes of the other basket can be used to perform cauterization.

[0284] The electrode only needs to be composed of at least a conductive material, and can be made of metallic materials such as copper, gold, platinum, aluminum, iron, or alloys thereof. Furthermore, to improve contrast enhancement to X-rays when using the catheter, the electrode is preferably made of platinum or an alloy thereof.

[0285] It is preferable that electrodes are arranged on the outer surface of the wire. This makes it easier to bring the electrodes into contact with body tissue. The electrodes may be placed on the outer surface of the wire, or a recess may be formed on the outer surface of the wire and the electrodes may be embedded in the recess. Electrode material may be printed on the outer surface of the wire. The wire may be inserted into the lumen of the tube, and the electrodes may be arranged on the tube (preferably on the outer surface of the tube). For the configuration of the tube, refer to the description of the shaft 202.

[0286] It is preferable that a wire is connected to the electrode, and that the wire is located inside the catheter 201. It is preferable that a handle portion 205 is located at the proximal end of the catheter 201. It is preferable that the wire extends to the proximal end and is connected to a connector via the handle portion 205. It is preferable that the electrode is electrically connected to an external device such as a power supply or an electrocardiogram display unit via the connector.

[0287] The power supply unit applies energy to the body's tissues. The power supply unit has a power source that applies voltage, and by applying pulse voltage, for example, between multiple electrodes or between an electrode and a counter electrode plate, it can supply the electrodes with the power necessary to perform various procedures. The power supply is connected to the electrodes via wires.

[0288] The electrocardiogram display unit displays the intracardiac potential measured by the electrodes of the catheter 201 as an intracardiac electrocardiogram. The catheter 201 may be connected to the electrocardiogram display unit via a power supply unit, or it may be connected to the electrocardiogram display unit without going through a power supply unit. An electrocardiograph can be used as an example of an electrocardiogram display unit.

[0289] The conductor only needs to be composed of at least a conductive material, and for example, iron wire, silver wire, stainless steel wire, copper wire, tungsten wire, nickel-titanium wire, etc. can be used. Preferably, the conductor contains a conductive material as a core material, and the core material is covered with an insulating material. As the insulating material, fluororesin (for example, PTFE, PFA, FEP, ETFE), polyolefin resin (for example, polyethylene or polypropylene), polyvinyl chloride resin, etc. can be used.

[0290] It is preferable that the proximal basket 221 and the distal basket 241 each have electrodes, but either the proximal basket 221 or the distal basket 241 may have electrodes. The distal basket 241 can be used to fix the catheter 201 inside the body, and it is not essential that it has electrodes, so for example, the proximal basket 221 may have electrodes while the distal basket 241 does not.

[0291] The number of electrodes 211 in the proximal basket 221 may be greater than or less than the number of electrodes 231 in the distal basket 241, or they may be the same number.

[0292] The proximal basket 221 preferably has at least one of an electrode for cauterization and an electrode for potential measurement. The distal basket 241 preferably has at least one of an electrode for cauterization and an electrode for potential measurement. Mapping may also be performed using the electrode for potential measurement, and the same applies in the following description.

[0293] As shown in Figure 34, the proximal basket 221 may have only an electrode 291 for cauterization and may not have an electrode for potential measurement. In that case, the distal basket 241 may have only an electrode 292 for potential measurement and may not have an electrode for cauterization. By measuring the potential using the electrode 231 of the distal basket 241 which is introduced into the body first, and then advancing the catheter 201 distally, cauterization can be performed with the electrode 211 of the proximal basket 221 which is inserted following, thus enabling the procedure to be performed efficiently.

[0294] It is preferable that all electrodes 211 in the proximal basket 221 are electrodes 291 for cauterization. It is preferable that all electrodes 231 in the distal basket 241 are electrodes 292 for potential measurement.

[0295] As another example, as shown in Figure 35, the proximal basket 221 may have only an electrode 292 for potential measurement and not an electrode for cauterization. In that case, the distal basket 241 may have only an electrode 291 for cauterization and not an electrode for potential measurement. Since potential measurement can be performed with the electrode 211 of the proximal basket 221 located at the front, and then cauterization can be performed with the electrode 231 of the distal basket 241 located at the back, the procedure can be performed efficiently.

[0296] Current may be passed between the multiple electrodes 211 of the proximal basket 221. Current may be passed between the multiple electrodes 231 of the distal basket 241. Also, current may be passed between the electrodes 211 of the proximal basket 221 and the electrodes 231 of the distal basket 241.

[0297] As shown in Figures 30 to 32, it is preferable that the handle portion 205 has a first connector 281 that is connected to the electrode for cauterization but not to the electrode for potential measurement and is connected to the power supply, and a second connector 282 that is connected to the electrode for potential measurement but not to the electrode for cauterization and is connected to the electrocardiogram display unit. In Figures 30 to 32, the handle portion 205 includes a first handle 206 connected to the proximal part of the shaft 202, and the first handle 206 is provided with the first connector 281 and the second connector 282.

[0298] When the catheter 201 is inserted into the body and the expansion portion 220 reaches the second state, it is preferable that the distal basket 241 contacts the inner wall of the pulmonary vein, and more preferably that the electrode 231 of the distal basket 241 contacts the inner wall of the pulmonary vein.

[0299] Electrodes may be placed on all the wires in a single basket. Or, electrodes may be placed on only some of the wires among the multiple wires in a single basket.

[0300] A single wire may have only one electrode, or it may have multiple electrodes.

[0301] Preferably, the first wire 222 has a plurality of electrodes 211 arranged along the direction of extension of the first wire 222. Preferably, the second wire 242 has a plurality of electrodes 231 arranged along the direction of extension of the second wire 242.

[0302] The distal basket 241 is preferably located distal to the distal end 202a of the shaft 202. The distal basket 241 is preferably not joined to the shaft 202.

[0303] It is preferable that neither the proximal basket 221 nor the distal basket 241 is arranged to completely enclose the other.

[0304] As shown in Figures 30 to 36, the distal basket 241 may overlap a portion of the proximal basket 221 in the longitudinal direction x. Preferably, the distal basket 241 does not overlap the entire proximal basket 221 in the longitudinal direction x. This makes it possible to obtain a catheter with a shorter total length of the proximal basket 221 and distal basket 241 than the catheter shown in Figure 37. Also, if electrodes are placed on both baskets, it becomes easier to reduce the distance between the electrodes. If both electrodes on each basket are used as ablation electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed efficiently. In this document, the total length of the proximal basket 221 and distal basket 241 means the length from the distal end 241a of the distal basket 241 to the proximal end 221b of the proximal basket 221 in the longitudinal direction x.

[0305] When we say that parts of the baskets overlap, we mean that they overlap for any length in the longitudinal direction x (for example, between 1 cm and 10 cm), not at any single point along the longitudinal direction x. This can also be rephrased as the distal end 221a of the proximal basket 221 being located distal to the proximal end 241b of the distal basket 241.

[0306] As a result of the distal basket 241 overlapping with a portion of the proximal basket 221 in the longitudinal direction x, the first wire 222 and the second wire 242 may intersect when the catheter 201 is viewed from the radial direction y.

[0307] As shown in Figure 37, the proximal basket 221 and the distal basket 241 may be arranged in series in the longitudinal direction x. That is, the proximal basket 221 and the distal basket 241 may be arranged without overlapping in the longitudinal direction x. This makes it possible to obtain a catheter in which the total length of the proximal basket 221 and the distal basket 241 is longer than that of the catheters shown in Figures 30 to 36.

[0308] The distal end 221a of the proximal basket 221 refers to the most distal position visible in a side view of the catheter 201, excluding any portion that is covered by other components and therefore not visible. The same applies to the proximal end 221b of the proximal basket 221, and the distal end 241a and proximal end 241b of the distal basket 241.

[0309] As shown in Figure 33, in the longitudinal direction x, it is preferable that the distal end 221a of the proximal basket 221 is located between the distal end 241a of the distal basket 241 and the maximum outer diameter position 241c. By positioning the distal end 221a in this manner, the two baskets are more likely to overlap over a wide area.

[0310] As shown in Figure 33, in the longitudinal direction x, it is preferable that the proximal end 241b of the distal basket 241 is located between the maximum outer diameter position 221c of the proximal basket 221 and the proximal end 221b. By positioning the proximal end 241b in this manner, the two baskets are more likely to overlap over a wide area.

[0311] As shown in Figure 36, it is preferable that in the longitudinal direction x, the distal end 221a of the proximal basket 221 is located between the proximal end 241b of the distal basket 241 and the maximum outer diameter position 241c of the distal basket 241. By positioning the proximal end 241b in this manner, it becomes easier to obtain a catheter in which the combined length of the proximal basket 221 and the distal basket 241 is longer than that of the catheter shown in Figure 33, while overlapping the two baskets to an appropriate extent.

[0312] As shown in Figure 36, in the longitudinal direction x, it is preferable that the proximal end 241b of the distal basket 241 is located between the maximum outer diameter position 221c of the proximal basket 221 and the distal end 221a of the proximal basket 221. By positioning the proximal end 241b in this manner, it becomes easier to obtain a catheter in which the total length of the proximal basket 221 and the distal basket 241 is longer than that of the catheter shown in Figure 33, while overlapping the two baskets to an appropriate extent.

[0313] Although not shown in the figures, in the longitudinal direction x, the distal end 221a of the proximal basket 221 is located between the distal end 241a of the distal basket 241 and the maximum outer diameter position 241c, and the proximal end 241b of the distal basket 241 may be located between the maximum outer diameter position 221c of the proximal basket 221 and the distal end 221a. Also, in the longitudinal direction x, the distal end 221a of the proximal basket 221 is located between the proximal end 241b of the distal basket 241 and the maximum outer diameter position 241c, and the proximal end 241b of the distal basket 241 may be located between the maximum outer diameter position 221c of the proximal basket 221 and the proximal end 221b.

[0314] As shown in Figure 37, it is preferable that in the longitudinal direction x, the distal end 221a of the proximal basket 221 is located more proximal to the proximal end 241a of the distal basket 241. This makes it possible to obtain a catheter in which the total length of the proximal basket 221 and the distal basket 241 is longer than that of the catheters shown in Figures 30 to 36.

[0315] As shown in Figure 40, it is preferable that the proximal end 241b of the distal basket 241 is in the same position as the proximal end 221b of the proximal basket 221 in the longitudinal direction x. By positioning the proximal end 241b in this way, the entire proximal basket 221 can be made to overlap with the distal basket 241.

[0316] As shown in Figures 33 and 36, when both the proximal basket 221 and the distal basket 241 are fully expanded, the catheter 201 may have, in the longitudinal direction x, a first portion 251 where the proximal basket 221 and the distal basket 241 overlap, and a second portion 252 of the proximal basket 221 that does not overlap with the distal basket 241. By providing the first portion 251 in this way, it becomes easier to reduce the distance between the electrodes of the proximal basket 221 and the distal basket 241. As a result, the energy density when current is passed between the electrodes can be increased, so that the ablation procedure can be performed efficiently.

[0317] As shown in Figure 33, when both the distal basket 241 and the proximal basket 221 are fully expanded, it is preferable that the length of the first portion 251 is longer than the length of the second portion 252. Setting the first portion 251 in this way makes it easier to reduce the distance between the electrodes of the proximal basket 221 and the distal basket 241, respectively. Here, the length of the first portion 251 and the length of the second portion 252 refer to the length in the longitudinal direction x.

[0318] As shown in Figure 36, when both the distal basket 241 and the proximal basket 221 are fully expanded, the length of the first portion 251 may be shorter than the length of the second portion 252. By setting the first portion 251 in this way, it becomes easier to obtain a catheter in which the sum of the lengths of the proximal basket 221 and the distal basket 241 is longer than that of the catheter shown in Figure 33, while overlapping the two baskets within an appropriate range.

[0319] In Figures 33, 36, and 40, with both the proximal basket 221 and the distal basket 241 fully expanded, the catheter 201 has a third portion 253 of the distal basket 241 that does not overlap with the proximal basket 221 in the longitudinal direction x. As shown in Figure 33, it is preferable that the third portion 253 is shorter than the first portion 251 in the longitudinal direction x. As shown in Figure 36, the third portion 253 may be longer than the first portion 251 in the longitudinal direction x. The third portion 253 may be longer than the second portion 252, or shorter than the second portion 252.

[0320] As shown in Figure 40, when both the proximal basket 221 and the distal basket 241 are fully expanded, the catheter 201 may have the entire proximal basket 221 overlapping the distal basket 241 in the longitudinal direction x. That is, the catheter 201 may have a first portion 251 and a third portion 253, but may not have a second portion 252.

[0321] As shown in Figure 32, it is preferable that the expansion portion 220 takes a third state in which both the distal basket 241 and the proximal basket 221 are expanded. In the third state, the further expansion of the proximal basket 221 prevents displacement within the body by the proximal basket 221 in addition to the distal basket 241. Furthermore, if the proximal basket 221 has a cauterizing electrode, cauterization can be performed by the cauterizing electrode of the proximal basket 221 while preventing displacement of the catheter 201 within the body by at least the distal basket 241, thus facilitating cauterization.

[0322] When the catheter 201 is inserted into the body and the expansion portion 220 reaches the third state, it is preferable that the distal basket 241 contacts the inner wall of the pulmonary vein and the proximal basket 221 contacts the inner wall of the antrum of the pulmonary vein, and it is more preferable that the electrode of the distal basket 241 contacts the inner wall of the pulmonary vein and the electrode of the proximal basket 221 contacts the inner wall of the antrum of the pulmonary vein.

[0323] It is preferable that the expansion portion 220 is configured to transition in the order of a first state and then a second state. It is more preferable that the expansion portion 220 is configured to transition in the order of a first state, then a second state and then a third state. When the expansion portion 220 transitions from the second state to the third state, it is preferable that the distal basket 241 reaches its maximum outer diameter before the proximal basket 221.

[0324] In the second and / or third state, the maximum outer diameter of the distal basket 241 may be greater than or less than the maximum outer diameter of the proximal basket 221.

[0325] To facilitate the fixation of the catheter 201 within the body, the catheter 201 may have the following configuration: The outer surface of the second wire 242 may be made of a material with lower hardness (preferably Shore D hardness) than the outer surface of the first wire 222. This increases the frictional force acting between the second wire 242 and the inner wall of the body cavity when the distal basket 241 is expanded, thereby suppressing displacement of the catheter 201 within the body when the distal basket 241 is expanded. Shore D hardness is measured according to ISO 868:2003 Plastic Durometer Hardness Test Method.

[0326] A non-slip layer may be provided on the outer surface of the second wire 242. Suitable materials for the non-slip layer include elastomer resins such as polyamide elastomer, polyester elastomer, and polyurethane elastomer.

[0327] The anti-slip layer is preferably provided on the portion of the second wire 242 where no electrodes are located. Multiple anti-slip layers may be provided intermittently along the extending direction of the second wire 242.

[0328] The surface roughness Ra of the outer surface of the second wire 242 may be greater than the surface roughness Ra of the outer surface of the first wire 222. This configuration also increases the frictional force acting between the second wire 242 and the inner wall of the body cavity when the distal basket 241 is expanded, thereby suppressing displacement of the catheter 201 within the body when the distal basket 241 is expanded. The surface roughness Ra of the outer surface of the wire corresponds to the arithmetic mean roughness Ra specified in JIS B 0601 (2001) and is measured in accordance with JIS B 0633 (2001). For measurement, a measuring instrument specified in JIS B 0651 (2001) (for example, an ultra-precision non-contact three-dimensional measuring device, model: NH-3SP, manufactured by Mitaka Kohki Co., Ltd.) is used.

[0329] The surface roughness Ra of the outer surface of the second wire 242 may be 1.1 times or more, 1.2 times or more, 1.5 times or more, and may be 10.0 times or less, 9.0 times or less, or 8.0 times or less than or equal to the surface roughness Ra of the outer surface of the first wire 222.

[0330] The surface roughness Ra of the outer surface of the second wire 242 may be greater than the surface roughness Ra of the outer surface of the electrode of the distal basket 241.

[0331] Next, we will describe the mechanism for expanding the basket.

[0332] As shown in Figures 34 to 35, when the shaft 202 has a lumen 202c extending in the longitudinal direction x, it is preferable that the catheter 201 extends in the longitudinal direction x, is connected to at least one of the proximal basket 221 and the distal basket 241, is inserted into the lumen 202c of the shaft 202, and has a traction member 261 that is movable in the longitudinal direction x relative to the shaft 202. The traction member 261 transmits the operation on the proximal side to the proximal basket 221 and / or the distal basket 241. It is preferable that the expansion portion 220 transitions from a first state to a second state by moving the traction member 261 proximal to the shaft 202. Because the expansion portion 220 expands in stages by changing the relative position of the shaft 202 and the traction member 261, it becomes easier to bring the expansion portion 220 into contact with the lesion. Figures 34 to 35 show an example in which the traction member 261 is connected to the distal basket 241.

[0333] In Figures 30 to 32, the handle portion 205 has a first handle 206 connected to the proximal part of the shaft 202 and a second handle 207 connected to the proximal part of the traction member 261. As shown in Figures 34 to 35, it is preferable that the first handle 206 has a hollow portion 206c inside, and it is preferable that the traction member 261 is inserted through the hollow portion 206c.

[0334] The traction member 261 preferably has an elongated shape. The traction member 261 may be a single wire or may have a structure consisting of multiple linear objects. The traction member 261 preferably extends along the longitudinal direction x of the shaft 202. The shaft 202 may have a distal opening and a proximal opening that communicate with the lumen 202c. As can be seen from Figures 34 to 35, the traction member 261 preferably extends from the distal opening of the shaft 202. The traction member 261 preferably extends from the proximal side of the first handle 206. The proximal opening of the shaft 202 preferably communicates with the hollow portion 206c of the first handle 206.

[0335] The traction member 261 may have a solid shape or a hollow shape. A cylindrical body can be an example of a hollow traction member 261. The traction member 261 may be a solid metal wire or resin wire covered by a coiled cylindrical body made of metal and / or synthetic resin.

[0336] The traction member 261 can be made of, for example, metals such as stainless steel, carbon steel, and nickel-titanium alloy, or synthetic resins such as polyamide resin (e.g., nylon), polyolefin resin (e.g., polyethylene and polypropylene), polyester resin (e.g., PET), aromatic polyetherketone resin (e.g., PEEK), polyimide resin, and fluororesin (e.g., PTFE, PFA, FEP, ETFE).

[0337] As shown in Figure 32, when the expansion section 220 takes a third state in which both the distal basket 241 and the proximal basket 221 are expanded, it is preferable that the traction member 261 moves proximal to the shaft 202, causing the expansion section 220 to transition in the order of the first state, second state, and third state. First, it transitions from the first state (Figure 30) to the second state (Figure 31), and as the distal basket 241 expands, the distal basket 241 comes into contact with the body tissue, thus fixing the catheter 201 inside the body. Then, it transitions to the third state (Figure 32), and displacement inside the body can be prevented not only by the distal basket 241 but also by the proximal basket 221. Furthermore, if the proximal basket 221 has a cauterizing electrode, cauterization can be performed by the cauterizing electrode of the proximal basket 221 while preventing displacement inside the body of the catheter 201 with at least the distal basket 241, thus facilitating cauterization. Therefore, by setting the expansion order of the baskets in this way, operations such as cauterization become easier to perform.

[0338] As shown in Figures 34 and 35, the catheter 201 may have a first connection portion 271 to which the distal end of the traction member 261 and the distal end of the distal basket 241 are connected. With this configuration, the distal basket 241 can be expanded or contracted by moving the traction member 261 distally or proximal. As shown in Figure 34, it is preferable that the distal end of the traction member 261 and the plurality of second wires 242 constituting the distal basket 241 are connected to each other at the first connection portion 271.

[0339] The connection method at the first connection part 271 can include physical fixing methods such as welding, silver brazing, soldering, crimping, bonding with adhesive, engagement, fitting, linking, bundling, and fastening, or a combination thereof. At least one of these methods can also be used when connecting the second connection part 272, third connection part 273, fourth connection part 274, and at least two other elements, as described later. Here, "connection" includes both forms in which at least two elements are directly connected and forms in which at least two elements are indirectly connected via one or more other elements.

[0340] In the first connection section 271, the traction member 261 and the second wire 242 may or may not be in contact with each other.

[0341] As shown in Figures 34 and 35, the first connection portion 271 may be connected to the traction member 261 and the plurality of second wires 242 by a tip 264. The shape of the tip 264 is not particularly limited, but the tip 264 may have one or more insertion openings in at least a portion of the longitudinal direction x of the shaft 202 into which the distal ends of the plurality of second wires 242 and / or the traction member 261 are inserted. For example, in Figure 34, the tip 264 has a first insertion opening 264m into which the distal end of the traction member 261 is inserted, and a second insertion opening 264n into which the distal ends of the plurality of second wires 242 are inserted.

[0342] In the radial direction y of the shaft 202, it is preferable that the second insertion opening 264n is positioned outward from the first insertion opening 264m. In the radial direction y of the shaft 202, it is preferable that the first insertion opening 264m is positioned so as to coincide with the central axis in the longitudinal direction x of the shaft 202.

[0343] A recess provided on the outer side of the tip 264 in the radial direction y may be the second insertion opening 264n. The tip 264 may have an outer cylinder portion and an inner cylinder portion, and the space between the outer cylinder portion and the inner cylinder portion may be the second insertion opening 264n. One or more second insertion openings 264n may be provided.

[0344] The tip 264 can be made of the same material as at least one of the first wire 222, the second wire 242, the traction member 261, and the shaft 202.

[0345] As shown in Figures 34 to 35, the catheter 201 may have a cylindrical member 265 positioned distal to the distal end of the shaft 202 and proximal to the first connection portion 271, with a traction member 261 inserted into the lumen 66c of the cylindrical member 265, and a cylindrical member 265 that is movable in the longitudinal direction x of the traction member 261, and a second connection portion 272 to which the proximal end of the distal basket 241 and the cylindrical member 265 are connected. With this configuration, when the traction member 261 moves distally or proximal, the cylindrical member 265 moves relative to the traction member 261, and the distance from the first connection portion 271 to the second connection portion 272 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the distal basket 241.

[0346] The cylindrical member 265 is a member for binding the first wire 222 of the proximal basket 221 and the second wire 242 of the distal basket 241. The cylindrical member 265 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 265 is movable distally or proximal relative to the traction member 261. It is preferable that the cylindrical member 265 is not fixed to the traction member 261.

[0347] The cylindrical member 265 can be made of the same material as at least one of the first wire 222, the second wire 242, the traction member 261, the shaft 202, and the tip 264.

[0348] As shown in Figure 34, it is preferable that a first insertion opening 265m is provided on the outer radial y portion of the cylindrical member 265 into which the proximal end of the second wire 242 of the distal basket 241 is inserted. The second wire 242 may be inserted into the first insertion opening 265m and the cylindrical member 265 may be crimped from the outside. The first insertion opening 265m may be a recess provided on the outer radial y portion of the cylindrical member 265. The cylindrical member 265 may have an outer cylinder and an inner cylinder, and the space between the outer cylinder and the inner cylinder may be the first insertion opening 265m. It is preferable that the first insertion opening 265m is located radially y outward from the lumen 265c of the cylindrical member 265.

[0349] Although not shown in the diagram, the second wire 242 can be connected to any part of the cylindrical member 265, as long as it does not obstruct the movement of the traction member 261. For example, the second connection portion 272 may be formed by joining the second wire 242 to the outer surface of the cylindrical member 265.

[0350] As shown in Figures 34 to 35, the catheter 201 may have a third connection portion 273 to which the distal end of the proximal basket 221 is connected to the cylindrical member 266. With this configuration, the proximal basket 221 can be expanded or contracted by moving the traction member 261 distally or proximal. Preferably, the distal end of the traction member 261 and the plurality of first wires 222 constituting the proximal basket 221 are connected to each other at the third connection portion 273.

[0351] In the third connection section 273, the distal end of the proximal basket 221 can be connected to the cylindrical member 265 in the same manner as in the second connection section 272, except that the part of the wire being connected is either the distal or proximal end. Figure 34 shows an example in which the cylindrical member 265 has a second insertion port 265n into which the distal end of the proximal basket 221 is inserted.

[0352] In the cylindrical member 265, it is preferable that the second insertion opening 265n is located distal to the first insertion opening 265m. By arranging the first insertion opening 265m and the second insertion opening 265n in this way, the two baskets are more likely to overlap over a wide area.

[0353] As shown in Figures 34 to 35, the catheter 201 may have a fourth connection portion 274 to which the proximal end of the proximal basket 221 and the distal end of the shaft 202 are connected. With this configuration, as the traction member 261 moves distally or proximal, the proximal basket 221 curves and / or bends, and the distance from the third connection portion 273 to the fourth connection portion 274 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the proximal basket 221. Preferably, the first wire 222 and the shaft 202 constituting the proximal basket 221 are connected to each other at the fourth connection portion 274.

[0354] In the fourth connection section 274, the proximal end of the proximal basket 221 can be connected to the distal end of the shaft 202 in the same manner as in the second connection section 272. Figure 34 shows an example in which the shaft 202 has an insertion opening 202f into which the proximal end of the first wire 222 is inserted. It is preferable that the multiple first wires 222 are not fixed to the traction member 261 in the fourth connection section 274.

[0355] As shown in Figure 34, in the longitudinal direction x, the distal end of the insertion port 202f of the shaft 202 may be at the same position as the distal end of the lumen 202c of the shaft 202. In the longitudinal direction x, the distal end of the insertion port 202f of the shaft 202 may be located proximal to the distal end of the lumen 202c. In the radial direction y, it is preferable that the insertion port 202f is positioned outward from the lumen 202c.

[0356] Although not shown in the figures, the first wire 222 and the cylindrical member 265 may be in contact when the proximal basket 221 is in its most expanded state, and the inner surface of the proximal basket 221 in the radial direction y may be in contact with the proximal end of the cylindrical member 265.

[0357] As can be seen from Figure 34, it is preferable that the cylindrical member 265 and the tip 264 are in contact when the distal basket 241 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 265 and the proximal end of the tip 264 are in contact.

[0358] As can be seen from Figure 33, it is preferable that the cylindrical member 265 and the second wire 242 are in contact when the distal basket 241 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 265 and the inner surface of the distal basket 241 in the radial direction y are in contact.

[0359] Although not shown in the diagram, when the proximal basket 221 is in its most expanded state, the cylindrical member 265 and the shaft 202 may be in contact, or the proximal end of the cylindrical member 265 and the distal end of the shaft 202 may be in contact.

[0360] As shown in Figures 30 to 36, it is preferable that the second connection portion 272 is located proximal to the third connection portion 273 in the longitudinal direction x. This makes it possible to obtain a catheter in which the total length of the proximal basket 221 and the distal basket 241 is shorter than that of the catheter shown in Figure 37. Also, if electrodes are placed on both baskets, it becomes easier to reduce the distance between the electrodes. If both electrodes on each basket are used as ablation electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed efficiently.

[0361] As shown in Figure 37, in the longitudinal direction x, the second connection portion 272 may be located distal to the third connection portion 273. This makes it possible to obtain a catheter in which the total length of the proximal basket 221 and the distal basket 241 is longer than that of the catheters shown in Figures 30 to 36.

[0362] As can be seen from Figure 39, it is preferable that the distal basket 241 and the proximal basket 221 move relative to each other when both are in their most expanded state. Since the position of the proximal basket 221 relative to the distal basket 241 can be changed, the electrode position can be adjusted to suit the shape of the patient's pulmonary veins.

[0363] In the catheter 201 shown in Figures 37 to 38, an example is shown in which the distal end of the proximal basket 221 and the proximal end of the distal basket 241 are connected to the same cylindrical member 265. However, in order to configure the two baskets to move relative to each other, as shown in Figure 39, the distal end of the proximal basket 221 may be connected to the first cylindrical member 268 and the proximal end of the distal basket 241 may be connected to the second cylindrical member 269. In that case, it is preferable that the second cylindrical member 269 is inserted through the lumen of the first cylindrical member 268, a traction member 261 is inserted through the lumen of the second cylindrical member 269, and that the first cylindrical member 268 and the second cylindrical member 269 are each movable in the longitudinal direction x of the traction member 261. It is preferable that the second cylindrical member 269 extends to the proximal part of the catheter 201 (for example, the handle part 205) or is connected to a long member that extends to the proximal part of the catheter 201 (for example, the handle part 205). By moving the second cylindrical member 269 or the elongated member relative to the first cylindrical member 268, the distal basket 241 and the proximal basket 221 can be moved relative to each other.

[0364] For further details regarding the configuration of the first cylindrical member 268 and the second cylindrical member 269, please refer to the description of the cylindrical member 265.

[0365] Other basket expansion mechanisms will be described with reference to Figures 40 to 41. If the shaft 202 has a lumen 202c extending in the longitudinal direction x, the catheter 201 may further include a traction member 261 extending in the longitudinal direction x, connected to at least one of the proximal basket 221 and the distal basket 241, inserted into the lumen 202c of the shaft 202 and movable in the longitudinal direction x relative to the shaft 202; a first connection portion 271 to which the distal end of the traction member 261 and the distal end of the distal basket 241 are connected; and a cylindrical member 266 positioned distal to the distal end of the shaft 202 and proximal to the first connection portion 271, the lumen of which the traction member 261 is inserted and which is movable in the longitudinal direction of the traction member 261. In this case, it is preferable that the distal end of the proximal basket 221 is connected to the cylindrical member 266, and the proximal end of the distal basket 241 is connected to the proximal end of the proximal basket 221 and the distal end of the shaft 202. With this configuration, by moving the traction member 261 towards the proximal side, the proximal basket 221 and the distal basket 241 are curved or bent, and the distance from the first connection part 271 to the distal end of the shaft 202 in the longitudinal direction x, and the distance from the distal end of the proximal basket 221 to the distal end of the shaft 202 in the longitudinal direction x, are shortened. In this way, the proximal basket 221 and the distal basket 241 can be sequentially expanded by pulling the traction member 261.

[0366] For the configuration of the first connection part 271 shown in Figures 40 to 41, please refer to the explanation of the first connection part 271 shown in Figures 34 to 35.

[0367] The cylindrical member 266 is a member for binding the first wire 222 of the proximal basket 221. The cylindrical member 266 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 266 is movable distally or proximal to the traction member 261. It is preferable that the cylindrical member 266 is not fixed to the traction member 261.

[0368] The cylindrical member 266 can be made of the same material as at least one of the first wire 222, the second wire 242, the traction member 261, the shaft 202, and the tip 264.

[0369] For information on how to connect the distal end of the proximal basket 221 to the cylindrical member 266, please refer to the description of the third connection part 273 shown in Figures 34 to 35.

[0370] For information on how to connect the proximal end of the distal basket 241, the proximal end of the proximal basket 221, and the distal end of the shaft 202, please refer to the description of the fourth connection part 274 shown in Figures 34 to 35.

[0371] Referring to Figure 42, further expansion mechanisms of the basket will be described. The shaft 202 has a lumen 202c extending in the longitudinal direction x, and the catheter 201 extends in the longitudinal direction x and is connected to at least one of the proximal basket 221 and the distal basket 241, is inserted into the lumen 202c of the shaft 202, and has a traction member 261 that is movable in the longitudinal direction x relative to the shaft 202, the traction member 261 having a cylindrical outer member 262 and an inner member 263 disposed within the outer member 262 and movable in the longitudinal direction x relative to the outer member 262, the distal end of the proximal basket 221 may be connected to the distal end of the outer member 262, and the distal end of the distal basket 241 may be connected to the distal end of the inner member 263. The distal basket 241 can be expanded by the inner member 263 moving proximal, causing the distal basket 241 to curve and / or bend. Furthermore, as the outer member 262 moves proximal, the proximal basket 221 curves and / or bends, thereby allowing the proximal basket 221 to expand. By configuring the traction member 261 in this way, it becomes easy to expand and contract the proximal basket 221 and the distal basket 241 independently.

[0372] The inner member 263 may have a hollow shape, but it is preferable that it has a solid shape.

[0373] The outer member 262 preferably has a lumen through which the inner member 263 can be inserted.

[0374] It is preferable that the inner member 263 and the outer member 262 are movable in the longitudinal direction x relative to the shaft 202. It is preferable that the inner member 263 and the outer member 262 extend to the proximal portion of the shaft 202.

[0375] The inner member 263 and the distal end of the distal basket 241 may be connected by the tip 65 shown in Figure 33. For details on the connection between the inner member 263 and the distal basket 241, please refer to the description of the first connection part 271 shown in Figure 33, etc.

[0376] The connection between the outer member 262 and the proximal basket 221 can be described by referring to the explanation of the connection between the cylindrical member 265 and the proximal basket 221 (for example, the third connection part 273) shown in Figure 33, etc.

[0377] The proximal end of the distal basket 241 is preferably connected to the outer member 262. For the connection between the distal basket 241 and the outer member 262, refer to the description of the connection between the cylindrical member 265 and the distal basket 241 (for example, the second connection part 272) shown in Figure 33, etc.

[0378] The proximal end of the proximal basket 221 is preferably connected to the distal end of the shaft 202. For the connection between the proximal basket 221 and the shaft 202, refer to the description of the connection between the proximal basket 221 and the shaft 202 (for example, the fourth connection part 274) shown in Figure 33, etc.

[0379] As shown in Figure 43, when viewing the catheter 201 from distal to proximal, it is preferable that the first wire 222 and the second wire 242 are arranged alternately in the circumferential direction. It is preferable that the first wire 222 and the second wire 242 are arranged alternately in the circumferential direction when both the distal basket 241 and the proximal basket 221 are at their most expanded state. It is also preferable that the first wire 222 and the second wire 242 are arranged alternately in the circumferential direction when both the distal basket 241 and the proximal basket 221 are at their most contracted state.

[0380] As shown in Figure 44, it is preferable that the first wire 222 and the second wire 242 are arranged to overlap when the catheter 201 is viewed from the distal to the proximal end. In this case, a part of the first wire 222 and a part of the second wire 242 may overlap each other in the circumferential direction, or the entire first wire 222 may overlap with the second wire 242.

[0381] As shown in Figure 43, it is preferable that the first wire 222 and the second wire 242 are separated when both the distal basket 241 and the proximal basket 221 are at their most expanded state. It is also preferable that the first wire 222 and the second wire 242 are separated in the first portion when both the distal basket 241 and the proximal basket 221 are at their most expanded state. It is preferable that the first wire 222 and the second wire 242 are separated in the second portion 252 when both the distal basket 241 and the proximal basket 221 are at their most expanded state. When both the distal basket 241 and the proximal basket 221 are at their most expanded state and are each divided into an outer portion and an inner portion in the radial direction y, it is preferable that the outer portion of the distal basket 241 and the outer portion of the proximal basket 221 are separated.

[0382] As can be seen from Figures 30 and 31, it is preferable that the first wire 222 and the second wire 242 are in contact when at least one of the distal basket 241 and the proximal basket 221 is most contracted. It is more preferable that the first wire 222 and the second wire 242, which are adjacent to each other in the circumferential direction, are in contact when at least one of the distal basket 241 and the proximal basket 221 is most contracted. It is preferable that the first wire 222 and the second wire 242 are in contact in the first portion 251 when at least one of the distal basket 241 and the proximal basket 221 is most contracted. It is preferable that the first wire 222 and the second wire 242 are separated in the second portion 252 when at least one of the distal basket 241 and the proximal basket 221 is most contracted.

[0383] As shown in Figure 33, in the third state, it is preferable that electrodes are placed in the distal basket 241 and the proximal basket 221, respectively, in the first portion 251. It is preferable that all of these electrodes are electrodes for cauterization.

[0384] Although not shown in the figures, in the third state, it is preferable that an electrode is positioned in the portion of the proximal basket 221 that is proximal to the point where the first wire 222 and the second wire 242 intersect, and distal to the portion of the proximal basket 221 with the largest outer diameter, and it is more preferable that an electrode for cauterization is positioned therein.

[0385] Although not shown in the diagram, it is preferable that, in the fully expanded state of both the distal basket 241 and the proximal basket 221, electrodes for measuring potential are arranged in the second portion 252 of the proximal basket 221 and electrodes for measuring potential are arranged in the third portion 253 of the distal basket 241.

[0386] It is preferable that the cauterizing electrode is positioned proximal to the portion of the first wire 222 where the first wire 222 and the second wire 242 intersect.

[0387] It is preferable that the cauterizing electrode is positioned distal to the portion of the first wire 222 where the first wire 222 and the second wire 242 intersect.

[0388] It is preferable that the cauterizing electrode is positioned on the side of the second wire 242 that is proximal to the portion where the first wire 222 and the second wire 242 intersect.

[0389] It is preferable that the cauterizing electrode is positioned distal to the portion of the second wire 242 where the first wire 222 and the second wire 242 intersect.

[0390] An electrode for cauterization may be placed in the portion of the first wire 222 where the first wire 222 and the second wire 242 intersect.

[0391] An electrode for cauterization may be placed in the portion of the second wire 242 where the first wire 222 and the second wire 242 intersect.

[0392] The proximal basket 221 has a plurality of first wires 222 arranged in the circumferential direction, and the distal basket 241 has a plurality of second wires 242 arranged in the circumferential direction, preferably with the Young's modulus of the second wires 242 being smaller than that of the first wires 222. Because the second wires 242 are more flexible than the first wires 222, the distal basket 241 is more likely to expand before the proximal basket 221.

[0393] Young's modulus (Pa) can be measured, for example, using the following bending test method: The wire is held at both ends in the longitudinal direction, and a load is applied to the center of the wire in the longitudinal direction from a direction perpendicular to the longitudinal direction. The displacement is measured using a strain gauge or similar device, and Young's modulus is determined.

[0394] The proximal basket 221 has a plurality of first wires 222 arranged in the circumferential direction, and the distal basket 241 has a plurality of second wires 242 arranged in the circumferential direction, preferably with the bending stiffness of the second wires 242 being lower than that of the first wires 222. Because the second wires 242 are more easily bent than the first wires 222, the distal basket 241 is more likely to expand before the proximal basket 221.

[0395] Bending stiffness (Pa·m) ４ The bending stiffness (m) represents the resistance of the wires that make up the basket to bending, with a lower value indicating easier bending. Bending stiffness can be measured using a bending test method, for example, by following these steps: First, determine Young's modulus using the method described above. Next, observe the shape of the cross-section perpendicular to the longitudinal direction of the wire and measure the size of each part (width, length, etc.) of the cross-section to determine the second moment of area (m ４ ) is calculated. The bending stiffness is calculated from the product of Young's modulus and the second moment of area.

[0396] The second moment of area of ​​the second wire 242 is preferably smaller than the second moment of area of ​​the first wire 222. Because the second wire 242 is more flexible than the first wire 222, the distal basket 241 is more likely to expand before the proximal basket 221.

[0397] The cross-sectional shapes of the first wire 222 and the second wire 242 perpendicular to their longitudinal directions may be the same or different.

[0398] In a first state, if the proximal basket 221 has a plurality of first wires 222 arranged in the circumferential direction, and the distal basket 241 has a plurality of second wires 242 arranged in the circumferential direction, it is preferable that in the first state, the second wires 242 are longer than the first wires 222 in the longitudinal direction x of the shaft 202. It is even more preferable that in the first state, each of the second wires 242 is longer than all of the first wires 222 in the longitudinal direction x of the shaft 202. In the first state, the longer second wires 242 make it easier for the distal basket 241 to expand before the proximal basket 221. Here, it is said that the second wires 242 are longer than the first wires 222, meaning that the length of the longest wire among the plurality of second wires 242 is longer than the length of the longest wire among the plurality of first wires 222.

[0399] As shown in Figure 33, when both the distal basket 241 and the proximal basket 221 are in their most expanded state, it is preferable that the maximum outer diameter of the proximal basket 221 is larger than the maximum outer diameter of the distal basket 241. This makes it easier to bring the distal basket 241 into contact with the inner wall of the pulmonary vein and the proximal basket 221 into contact with the antrum of the pulmonary vein.

[0400] When both the distal basket 241 and the proximal basket 221 are fully expanded, the maximum outer diameter of the proximal basket 221 may be smaller than the maximum outer diameter of the distal basket 241. This makes it easier to use when you want to firmly fix the catheter 201 inside the body with the distal basket 241, or when the antrum of the pulmonary veins is elevated due to a lesion or the like, and a smaller outer diameter of the proximal basket 221 is preferable.

[0401] The catheter according to the fourth embodiment comprises a shaft having a longitudinal direction, a proximal basket disposed at the distal end of the shaft, and a distal basket whose longitudinal direction at least a portion is disposed distal to the proximal basket, and an expansion portion having electrodes in at least one of the proximal basket and the distal basket, the gist of which is that the expansion portion takes the form of a first state in which both the distal basket and the proximal basket are contracted, and a second state in which the proximal basket is expanded and the distal basket is contracted. With the above catheter, the proximal basket expands in the second state so that it comes into contact with the body tissue, so the catheter can be fixed in the body and it is easier to perform potential measurement and cauterization using electrodes.

[0402] A catheter according to the fourth embodiment of the present disclosure will be described with reference to Figures 45 to 59. Figure 45 is a side view of the catheter according to the fourth embodiment of the present disclosure, showing the first state. Figure 46 is a side view of the catheter according to the fourth embodiment of the present disclosure, showing the second state. Figure 47 is a side view of the catheter according to the fourth embodiment of the present disclosure, showing the third state. Figure 48 is an enlarged side view of the distal side of the catheter shown in Figure 47. Figure 49 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 48. Figure 50 is a cross-sectional view (partial side view) showing a modified example of the catheter shown in Figure 49. Figure 51 is a side view showing a modified example of the catheter shown in Figure 48. Figure 52 is a side view showing a modified example of the catheter shown in Figure 48. Figure 53 is a cross-sectional view (partial side view) showing the connection state of each component on the distal side of the catheter shown in Figure 52. Figure 54 is a side view showing a modified example of the catheter shown in Figure 52. Figure 55 is a side view showing another modified example of the catheter shown in Figure 48. Figure 56 is a cross-sectional view (partially a side view) showing the connection state of each component on the distal side of the catheter shown in Figure 55. Figure 57 is a cross-sectional view (partially a side view) showing another modified example of the catheter shown in Figure 48. Figures 58 to 59 are schematic diagrams showing the arrangement of the first wire and the second wire when viewed from the distal side to the proximal side of the catheter according to the fourth embodiment of this disclosure. Note that some wires are omitted in the diagrams showing the connection state of each component. As shown in Figures 45 to 49, the catheter 301 comprises a shaft 302 and an expansion section 320 having a proximal basket 321 and a distal basket 341.

[0403] As shown in Figures 45 to 47, the shaft 302 has a longitudinal direction x. As shown in Figure 49, the shaft 302 preferably has a distal end 302a and a proximal end 302b in the longitudinal direction x. The proximal side of the shaft 302 refers to the direction toward the user or operator's hand relative to the longitudinal direction x of the shaft 302, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the treatment target. In each drawing, the right side of the figure is the proximal side, and the left side of the figure is the distal side. The shaft 302 preferably has a radial direction y and a circumferential direction z. The radial direction y refers to the radial direction of the shaft 302, in which case inward refers to the direction toward the center of the longitudinal axis of the shaft 302, and outward refers to the direction extending radially from the center of the longitudinal axis on the opposite side from inward. The circumferential direction z refers to the direction around the longitudinal axis of the shaft 302, i.e., the direction along the outer circumference of the shaft 302.

[0404] The shaft 302 can be composed of one or more members. Examples of the shaft 302 include a resin tube, a metal tube, a hollow body formed by arranging wires in a predetermined pattern, a hollow body with at least one of its inner or outer surfaces coated with resin, or a combination thereof, for example, connected in the longitudinal direction x. The resin tube can be manufactured, for example, by extrusion molding. Examples of hollow bodies formed by arranging wires in a predetermined pattern include cylindrical bodies having a mesh structure by simply crossing or weaving wires, and coils in which wires are wound. The wires may be one or more single wires or one or more stranded wires. The type of mesh structure is not particularly limited, nor are the number of turns or density of the coils. The mesh structure or coil may be formed at a constant density over the entire longitudinal direction x of the shaft 302, or it may be formed so that the density differs depending on the position in the longitudinal direction x. To increase the flexibility of the metal tube, notches or grooves may be formed on the outer surface of the metal tube. The shape of the cuts and grooves can be straight, arcuate, annular, spiral, or a combination of these.

[0405] The shaft 302 preferably has one or more lumens, and more preferably has only one. The shaft 302 is preferably a single-lumen tube.

[0406] The shaft 302 is preferably flexible and elastic. The material constituting the shaft 302 is preferably resin, metal, or a combination of resin and metal. Using resin makes it easier to impart flexibility and elasticity to the shaft 302. Using metal improves the ease of insertion of the catheter 301 into the vascular lumen.

[0407] The shaft 302 may have a single-layer structure or a multi-layer structure. If the shaft 302 has a multi-layer structure, for example, a reinforcing material such as a wire made of metal such as stainless steel, carbon steel, or nickel-titanium alloy can be provided as an intermediate layer of the resin tube that constitutes the shaft 302.

[0408] Examples of resins that make up the shaft 302 include polyamide resins such as polyamide and polyamide elastomer, polyester resins such as polyethylene terephthalate and polyester elastomer, polyurethane resins such as polyurethane and polyurethane elastomer, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyphenylene sulfide resin, polystyrene resin, fluororesin, vinyl chloride resin, silicone resin, natural rubber, synthetic rubber, and polyimide. These may be used individually or in combination of two or more. Examples of polyamides include nylon 12 and nylon 11. Examples of polyamide elastomers include polyether ester amide elastomer and polyamide ether elastomer.

[0409] Examples of metals that make up the shaft 302 include stainless steel such as SUS304 and SUS316, platinum, nickel, cobalt, chromium, titanium, tungsten, aluminum, gold, silver, Ni-Ti alloy, and Co-Cr alloy. These may be used individually or in combination of two or more.

[0410] As shown in Figures 45 to 49, the catheter 301 has a proximal basket 321 located at the distal end of the shaft 302, and a distal basket 341 located distal to the proximal basket 321 in the longitudinal direction x, and at least one of the proximal basket 321 and the distal basket 341 is provided with an expansion portion 320 having electrodes. In the catheter 301, the proximal basket 321 and the distal basket 341 exist independently of each other. Hereinafter, for simplicity, both or one of the proximal basket 321 and the distal basket 341 may be referred to as "baskets".

[0411] The basket is capable of expanding and contracting in the radial direction y. Preferably, the basket deflates and reduces in diameter when not subjected to external forces other than gravity, and expands in diameter when subjected to external forces other than gravity. Preferably, the basket has a shape that is convex outward in the radial direction y when it has its maximum outer diameter.

[0412] It is preferable that the basket has both a radial and a circumferential direction. In this document, the case in which the radial and circumferential directions of the basket coincide with the radial direction y and circumferential direction z of the shaft 302 is given as an example, but these directions may be different from each other.

[0413] As shown in Figure 45, the expandable section 320 can take two states: a first state in which both the distal basket 341 and the proximal basket 321 are contracted, and a second state in which the proximal basket 321 is expanded and the distal basket 341 is contracted, as shown in Figure 46. The contracted state refers to a state in which the basket has not yet begun to expand, and the outer diameter of the basket is equal to its minimum outer diameter. The expanded state refers to a state in which the basket has not contracted, and the outer diameter of the basket is greater than its minimum outer diameter. The expanded state also includes a state in which the basket is expanded to its maximum outer diameter. With the above catheter, the catheter 301 can be inserted into the body because it is reduced in diameter in the first state. In the second state, the proximal basket 321 expands and comes into contact with the body tissue, so the catheter 301 can be fixed in the body by the proximal basket 321. In the second state, displacement of the catheter 301 within the body can be prevented, making it easier to perform procedures such as potential measurement and cauterization using electrodes on at least one of the distal basket 341 and the proximal basket 321.

[0414] Since the expansion section 320 can take on a second state, it is preferable that the proximal basket 321 and the distal basket 341 can each be expanded independently. That is, it is preferable that the proximal basket 321 and the distal basket 341 are configured to reach their maximum outer diameter at different times.

[0415] The expansion of the proximal basket 321 and the distal basket 341 may be synchronized. For example, it is preferable that the proximal basket 321 expands to its maximum outer diameter, followed by the distal basket 341, when the user operates the handle portion 305 or the traction member 361, which will be described later.

[0416] The catheter 301 should be configured such that the proximal basket 321 expands before the distal basket 341 when the expansion section 320 transitions from the first state to the second state. In other words, it is preferable that, as a result of the user's operation on the proximal side, the distal basket 341 begins to expand after the proximal basket 321 begins to expand.

[0417] The basket preferably has multiple wires. The wires preferably have elasticity and / or flexibility. The elastic wires preferably have a curved shape and / or a bent shape. When an external force is applied, the wires preferably bend and / or curve so as to be convex outward in the radial direction y.

[0418] The wire is preferably a single-strand or stranded linear member. The shape of the cross-section perpendicular to the longitudinal direction of the single-strand wire may be, for example, circular, elliptical, polygonal, a part thereof, or a combination thereof, or it may be completely amorphous. Alternatively, it may be a shape with rounded corners.

[0419] It is preferable that a basket is formed by arranging multiple wires at equal or unequal intervals around the longitudinal axis of the shaft 302. One wire may be arranged so that its circumferential position does not change from the distal to the proximal side of the shaft 302, or one wire may be arranged spirally around the longitudinal axis of the shaft 302. The shape of the basket can be changed by adjusting the shape and arrangement of each wire.

[0420] A basket may be formed by connecting the distal ends of multiple wires to each other, and connecting the proximal ends of multiple wires to each other. Preferably, the distal and / or proximal ends of multiple wires are tied together.

[0421] The wire is preferably made of a metal or resin capable of maintaining its shape, and more preferably made of a shape memory alloy or shape memory resin. As the material for the wire, at least one of the metals and / or resins that make up the shaft 302 can be used. In particular, the wire is preferably made of a single or stranded metal wire, and more preferably a metal wire made of a Ni-Ti alloy.

[0422] The first wire 322 of the proximal basket 321 and the second wire 342 of the distal basket 341 may be made of the same material or of different materials.

[0423] There is no limit to the number of wires a single basket may have, but for example, it may be three or more, four or more, five or more, six or more, eight or more, ten or more, or twenty or fewer, or fifteen or fewer.

[0424] The proximal basket 321 preferably has a plurality of first wires 322 arranged in the circumferential direction. The distal basket 341 preferably has a plurality of second wires 342 arranged in the circumferential direction.

[0425] It is preferable that the first wire 322 and the second wire 342 are provided independently. It is preferable that the first wire 322 and the second wire 342 are not joined together. It is preferable that the first wire 322 and the second wire 342 are not connected. By separating the first wire 322 and the second wire 342 in this way, it becomes easier to impart a shape suitable for each individual basket and to expand each basket independently.

[0426] In the expansion section 320, at least one of the proximal basket 321 and the distal basket 341 has electrodes. As shown in Figures 45 to 49, it is preferable that the proximal basket 321 has multiple electrodes 311. It is preferable that the distal basket 341 has multiple electrodes 331. Because the expansion section 320 has multiple baskets, and each basket has electrodes, different functions can be assigned to each basket. For example, one basket can be used to fix the catheter 301 in the body or to measure potential, while the electrodes of the other basket can be used to perform cauterization.

[0427] The electrode only needs to be composed of at least a conductive material, and can be made of metallic materials such as copper, gold, platinum, aluminum, iron, or alloys thereof. Furthermore, to improve contrast enhancement to X-rays when using the catheter, the electrode is preferably made of platinum or an alloy thereof.

[0428] It is preferable that electrodes are arranged on the outer surface of the wire. This makes it easier to bring the electrodes into contact with body tissue. The electrodes may be placed on the outer surface of the wire, or a recess may be formed on the outer surface of the wire and the electrodes may be embedded in the recess. Electrode material may be printed on the outer surface of the wire. The wire may be inserted into the lumen of the tube, and the electrodes may be arranged on the tube (preferably on the outer surface of the tube). For the configuration of the tube, refer to the description of the shaft 302.

[0429] It is preferable that a wire is connected to the electrode, and that the wire is located inside the catheter 301. It is preferable that a handle portion 305 is located at the proximal end of the catheter 301. It is preferable that the wire extends to the proximal end and is connected to a connector via the handle portion 305. It is preferable that the electrode is electrically connected to an external device such as a power supply or an electrocardiogram display unit via the connector.

[0430] The power supply unit applies energy to the body's tissues. The power supply unit has a power source that applies voltage, and by applying pulse voltage, for example, between multiple electrodes or between an electrode and a counter electrode plate, it can supply the electrodes with the power necessary to perform various procedures. The power supply is connected to the electrodes via wires.

[0431] The electrocardiogram display unit displays the intracardiac potential measured by the electrodes of the catheter 301 as an intracardiac electrocardiogram. The catheter 301 may be connected to the electrocardiogram display unit via a power supply unit, or it may be connected to the electrocardiogram display unit without going through a power supply unit. An electrocardiograph can be used as an example of an electrocardiogram display unit.

[0432] The conductor only needs to be composed of at least a conductive material, and for example, iron wire, silver wire, stainless steel wire, copper wire, tungsten wire, nickel-titanium wire, etc. can be used. Preferably, the conductor contains a conductive material as a core material, and the core material is covered with an insulating material. As the insulating material, fluororesin (for example, PTFE, PFA, FEP, ETFE), polyolefin resin (for example, polyethylene or polypropylene), polyvinyl chloride resin, etc. can be used.

[0433] It is preferable that the proximal basket 321 and the distal basket 341 each have electrodes, but either the proximal basket 321 or the distal basket 341 may have electrodes. The proximal basket 321 can be used to fix the catheter 301 inside the body, and it is not essential that it has electrodes; for example, the distal basket 341 may have electrodes while the proximal basket 321 does not.

[0434] The number of electrodes 311 in the proximal basket 321 may be greater than or less than the number of electrodes 331 in the distal basket 341, or they may be the same number.

[0435] The proximal basket 321 preferably has at least one of an electrode for cauterization and an electrode for potential measurement. The distal basket 341 preferably has at least one of an electrode for cauterization and an electrode for potential measurement. Mapping may also be performed using the electrode for potential measurement, and the same applies in the following description.

[0436] As shown in Figure 49, the proximal basket 321 may have only an electrode 391 for cauterization and may not have an electrode for potential measurement. In that case, the distal basket 341 may have only an electrode 392 for potential measurement and may not have an electrode for cauterization. By measuring the potential using the electrode 331 of the distal basket 341 which is introduced into the body first, and then advancing the catheter 301 distally, cauterization can be performed with the electrode 311 of the proximal basket 321 which is inserted following, thus enabling the procedure to be performed efficiently.

[0437] It is preferable that all electrodes 311 in the proximal basket 321 are electrodes 391 for cauterization. It is preferable that all electrodes 331 in the distal basket 341 are electrodes 392 for potential measurement.

[0438] As another example, as shown in Figure 50, the proximal basket 321 may have only an electrode 392 for potential measurement and not an electrode for cauterization. In that case, the distal basket 341 may have only an electrode 391 for cauterization and not an electrode for potential measurement. Since potential measurement can be performed with the electrode 311 of the proximal basket 321 located at the front, and then cauterization can be performed with the electrode 331 of the distal basket 341 located at the back, the procedure can be performed efficiently.

[0439] Current may be passed between the multiple electrodes 311 of the proximal basket 321. Current may be passed between the multiple electrodes 331 of the distal basket 341. Also, current may be passed between the electrodes 311 of the proximal basket 321 and the electrodes 331 of the distal basket 341.

[0440] As shown in Figures 45 to 47, it is preferable that the handle portion 305 has a first connector 381 that is connected to the electrode for cauterization but not to the electrode for potential measurement and is connected to the power supply unit, and a second connector 382 that is connected to the electrode for potential measurement but not to the electrode for cauterization and is connected to the electrocardiogram display unit. In Figures 45 to 47, the handle portion 305 includes a first handle 306 connected to the proximal part of the shaft 302, and the first handle 306 is provided with the first connector 381 and the second connector 382.

[0441] When the catheter 301 is inserted into the body and the expansion portion 320 reaches the second state, it is preferable that the distal basket 341 contacts the inner wall of the pulmonary vein, and more preferably that the electrode 331 of the distal basket 341 contacts the inner wall of the pulmonary vein.

[0442] Electrodes may be placed on all the wires in a single basket. Or, electrodes may be placed on only some of the wires among the multiple wires in a single basket.

[0443] A single wire may have only one electrode, or it may have multiple electrodes.

[0444] Preferably, the first wire 322 has a plurality of electrodes 311 arranged along the direction of extension of the first wire 322. Preferably, the second wire 342 has a plurality of electrodes 331 arranged along the direction of extension of the second wire 342.

[0445] The distal basket 341 is preferably located distal to the distal end 302a of the shaft 302. The distal basket 341 is preferably not joined to the shaft 302.

[0446] It is preferable that neither the proximal basket 321 nor the distal basket 341 is arranged to completely enclose the other.

[0447] As shown in FIGS. 45 to 51, the distal basket 341 may be arranged to overlap a part of the proximal basket 321 in the longitudinal direction x. Preferably, the distal basket 341 does not overlap with all of the proximal basket 321 in the longitudinal direction x. Thereby, a catheter having a shorter total length of the proximal basket 321 and the distal basket 341 than the catheter shown in FIG. 52 can be obtained. Further, when electrodes are arranged on both of the two baskets, it becomes easier to reduce the distance between the electrodes. If both of the electrodes included in each basket are used as ablation electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed efficiently. In this document, the total length of the proximal basket 321 and the distal basket 341 means the length from the distal end 341a of the distal basket 341 to the proximal end 321b of the proximal basket 321 in the longitudinal direction x.

[0448] That a part of the baskets overlaps does not mean that they overlap at an arbitrary point in the longitudinal direction x, but means that they overlap at an arbitrary length (for example, 1 cm or more and 10 cm or less) in the longitudinal direction x. It can also be said that the distal end 321a of the proximal basket 321 is located on the distal side of the proximal end 341b of the distal basket 341.

[0449] As a result of the distal basket 341 being arranged to overlap a part of the proximal basket 321 in the longitudinal direction x, when the catheter 301 is viewed from the radial direction y, the first wire 322 and the second wire 342 may intersect.

[0450] As shown in FIG. 52, the proximal basket 321 and the distal basket 341 may be arranged in series in the longitudinal direction x. That is, in the longitudinal direction x, the proximal basket 321 and the distal basket 341 may be arranged without overlapping. Thereby, a catheter having a longer total length of the proximal basket 321 and the distal basket 341 than the catheter shown in FIGS. 45 to 51 can be obtained.

[0451] The distal end 321a of the proximal basket 321 refers to the most distal position among the positions visible in the side view of the catheter 301, excluding the portions covered by other members and not visible. The same applies to the proximal end 321b of the proximal basket 321, the distal end 341a of the distal basket 341, and the proximal end 341b of the distal basket 341.

[0452] As shown in FIG. 48, in the longitudinal direction x, it is preferable that the distal end 321a of the proximal basket 321 is located between the distal end 341a of the distal basket 341 and the maximum outer diameter position 341c. By arranging the distal end 321a at such a position, the two baskets are likely to overlap in a wide range.

[0453] As shown in FIG. 48, in the longitudinal direction x, it is preferable that the proximal end 341b of the distal basket 341 is located between the maximum outer diameter position 321c and the proximal end 321b of the proximal basket 321. By arranging the proximal end 341b at such a position, the two baskets are likely to overlap in a wide range.

[0454] As shown in FIG. 51, in the longitudinal direction x, it is preferable that the distal end 321a of the proximal basket 321 is located between the proximal end 341b of the distal basket 341 and the maximum outer diameter position 341c of the distal basket 341. By arranging the proximal end 341b at such a position, while overlapping the two baskets within an appropriate range, it becomes easier to obtain a catheter with a longer total length of the proximal basket 321 and the distal basket 341 than the catheter shown in FIG. 48.

[0455] As shown in FIG. 51, in the longitudinal direction x, it is preferable that the proximal end 341b of the distal basket 341 is located between the maximum outer diameter position 321c and the distal end 321a of the proximal basket 321. By arranging the proximal end 341b at such a position, while overlapping the two baskets within an appropriate range, it becomes easier to obtain a catheter with a longer total length of the proximal basket 321 and the distal basket 341 than the catheter shown in FIG. 48.

[0456] Although not shown in the figures, in the longitudinal direction x, the distal end 321a of the proximal basket 321 is located between the distal end 341a of the distal basket 341 and the maximum outer diameter position 341c, and the proximal end 341b of the distal basket 341 may be located between the maximum outer diameter position 321c of the proximal basket 321 and the distal end 321a. Also, in the longitudinal direction x, the distal end 321a of the proximal basket 321 is located between the proximal end 341b of the distal basket 341 and the maximum outer diameter position 341c, and the proximal end 341b of the distal basket 341 may be located between the maximum outer diameter position 321c of the proximal basket 321 and the proximal end 321b.

[0457] As shown in Figure 52, it is preferable that in the longitudinal direction x, the distal end 321a of the proximal basket 321 is located proximal to the proximal end 341a of the distal basket 341. This makes it possible to obtain a catheter in which the total length of the proximal basket 321 and the distal basket 341 is longer than that of the catheters shown in Figures 45 to 51.

[0458] As shown in Figure 55, it is preferable that the proximal end 341b of the distal basket 341 is in the same position as the proximal end 321b of the proximal basket 321 in the longitudinal direction x. By positioning the proximal end 341b in this way, the entire proximal basket 321 can be made to overlap with the distal basket 341.

[0459] As shown in Figures 48 and 51, when both the proximal basket 321 and the distal basket 341 are fully expanded, the catheter 301 may have, in the longitudinal direction x, a first portion 351 where the proximal basket 321 and the distal basket 341 overlap, and a second portion 352 of the proximal basket 321 that does not overlap with the distal basket 341. By providing the first portion 351 in this way, it becomes easier to reduce the distance between the electrodes of the proximal basket 321 and the distal basket 341. As a result, the energy density when current is passed between the electrodes can be increased, so that the ablation procedure can be performed efficiently.

[0460] As shown in Figure 48, when both the distal basket 341 and the proximal basket 321 are in their most expanded state, it is preferable that the length of the first portion 351 is longer than the length of the second portion 352. Setting the first portion 351 in this way makes it easier to reduce the distance between the electrodes of the proximal basket 321 and the distal basket 341, respectively. Here, the length of the first portion 351 and the length of the second portion 352 refer to the length in the longitudinal direction x.

[0461] As shown in Figure 51, when both the distal basket 341 and the proximal basket 321 are fully expanded, the length of the first portion 351 may be shorter than the length of the second portion 352. By setting the first portion 351 in this way, it becomes easier to obtain a catheter in which the sum of the lengths of the proximal basket 321 and the distal basket 341 is longer than that of the catheter shown in Figure 48, while overlapping the two baskets within an appropriate range.

[0462] In Figures 48, 51, and 55, with both the proximal basket 321 and the distal basket 341 fully expanded, the catheter 301 has a third portion 353 in the longitudinal direction x that does not overlap with the proximal basket 321 of the distal basket 341. As shown in Figure 48, it is preferable that the third portion 353 is shorter than the first portion 351 in the longitudinal direction x. As shown in Figure 51, the third portion 353 may be longer than the first portion 351 in the longitudinal direction x. The third portion 353 may be longer than the second portion 352, or shorter than the second portion 352.

[0463] As shown in Figure 55, when both the proximal basket 321 and the distal basket 341 are fully expanded, the catheter 301 may have the entire proximal basket 321 overlapping the distal basket 341 in the longitudinal direction x. That is, the catheter 301 may have a first portion 351 and a third portion 353, but may not have a second portion 352.

[0464] As shown in Figure 47, it is preferable that the expansion portion 320 takes a third state in which both the distal basket 341 and the proximal basket 321 are expanded. In the third state, the distal basket 341 expands further, which prevents displacement of the distal basket 341 in addition to the proximal basket 321. Furthermore, if the distal basket 341 has a cauterizing electrode, cauterization can be performed by the cauterizing electrode of the distal basket 341 while preventing displacement of the catheter 301 in the body by at least the proximal basket 321, thus facilitating cauterization.

[0465] When the catheter 301 is inserted into the body and the expansion portion 320 reaches the third state, it is preferable that the distal basket 341 contacts the inner wall of the pulmonary vein and the proximal basket 321 contacts the inner wall of the antrum of the pulmonary vein, and it is more preferable that the electrode of the distal basket 341 contacts the inner wall of the pulmonary vein and the electrode of the proximal basket 321 contacts the inner wall of the antrum of the pulmonary vein.

[0466] It is preferable that the expansion portion 320 is configured to transition in the order of a first state and then a second state. It is more preferable that the expansion portion 320 is configured to transition in the order of a first state, then a second state and then a third state. When the expansion portion 320 transitions from the second state to the third state, it is preferable that the proximal basket 321 reaches its maximum outer diameter before the distal basket 341.

[0467] In the second and / or third state, the maximum outer diameter of the distal basket 341 may be larger or smaller than the maximum outer diameter of the proximal basket 321.

[0468] To facilitate the fixation of the catheter 301 within the body, the catheter 301 may have the following configuration: The outer surface of the first wire 322 may be made of a material with lower hardness (preferably Shore D hardness) than the outer surface of the second wire 342. This increases the frictional force acting between the first wire 322 and the inner wall of the body cavity when the proximal basket 321 is expanded, thereby suppressing displacement of the catheter 301 within the body when the proximal basket 321 is expanded. Shore D hardness is measured according to ISO 868:2003 Plastic Durometer Hardness Test Method.

[0469] An anti-slip layer may be provided on the outer surface of the first wire 322. Suitable materials for the anti-slip layer include elastomer resins such as polyamide elastomer, polyester elastomer, and polyurethane elastomer.

[0470] The anti-slip layer is preferably provided on the portion of the first wire 322 where no electrodes are located. Multiple anti-slip layers may be provided intermittently along the extending direction of the first wire 322.

[0471] The surface roughness Ra of the outer surface of the first wire 322 may be greater than the surface roughness Ra of the outer surface of the second wire 342. This configuration also increases the frictional force acting between the first wire 322 and the inner wall of the body cavity when the proximal basket 321 is expanded, thereby suppressing displacement of the catheter 301 within the body when the proximal basket 321 is expanded. The surface roughness Ra of the outer surface of the wire corresponds to the arithmetic mean roughness Ra specified in JIS B 0601 (2001) and is measured in accordance with JIS B 0633 (2001). For measurement, a measuring instrument specified in JIS B 0651 (2001) (for example, an ultra-precision non-contact three-dimensional measuring device, model: NH-3SP, manufactured by Mitaka Kohki Co., Ltd.) is used.

[0472] The surface roughness Ra of the outer surface of the first wire 322 may be 1.1 times or more, 1.2 times or more, 1.5 times or more, and may be 10.0 times or less, 9.0 times or less, or 8.0 times or less, of the surface roughness Ra of the outer surface of the second wire 342.

[0473] The surface roughness Ra of the outer surface of the first wire 322 may be greater than the surface roughness Ra of the outer surface of the electrode of the proximal basket 321.

[0474] Next, we will describe the mechanism for expanding the basket.

[0475] As shown in Figures 49 to 50, when the shaft 302 has a lumen 302c extending in the longitudinal direction x, it is preferable that the catheter 301 extends in the longitudinal direction x, is connected to at least one of the proximal basket 321 and the distal basket 341, is inserted into the lumen 302c of the shaft 302, and has a traction member 361 that is movable in the longitudinal direction x relative to the shaft 302. The traction member 361 transmits the operation on the proximal side to the proximal basket 321 and / or the distal basket 341. It is preferable that the expansion portion 320 transitions from a first state to a second state by moving the traction member 361 proximal to the shaft 302. Because the expansion portion 320 expands in stages by changing the relative position of the shaft 302 and the traction member 361, it becomes easier to bring the expansion portion 320 into contact with the lesion. Figures 49 to 50 show an example in which the traction member 361 is connected to the distal basket 341.

[0476] In Figures 45 to 47, the handle portion 305 has a first handle 306 connected to the proximal part of the shaft 302 and a second handle 307 connected to the proximal part of the traction member 361. As shown in Figures 49 to 50, it is preferable that the first handle 306 has a hollow portion 306c inside, and it is preferable that the traction member 361 is inserted through the hollow portion 306c.

[0477] The traction member 361 preferably has an elongated shape. The traction member 361 may be a single wire or may have a structure consisting of multiple linear objects. The traction member 361 preferably extends along the longitudinal direction x of the shaft 302. The shaft 302 may have a distal opening and a proximal opening that communicate with the lumen 302c. As can be seen from Figures 49 to 50, the traction member 361 preferably extends from the distal opening of the shaft 302. The traction member 361 preferably extends from the proximal side of the first handle 306. The proximal opening of the shaft 302 preferably communicates with the hollow portion 306c of the first handle 306.

[0478] The traction member 361 may have a solid shape or a hollow shape. A cylindrical body can be an example of a hollow traction member 361. The traction member 361 may be a solid metal wire or resin wire covered by a coiled cylindrical body made of metal and / or synthetic resin.

[0479] The traction member 361 can be made of, for example, metals such as stainless steel, carbon steel, or nickel-titanium alloy, or synthetic resins such as polyamide resin (e.g., nylon), polyolefin resin (e.g., polyethylene or polypropylene), polyester resin (e.g., PET), aromatic polyetherketone resin (e.g., PEEK), polyimide resin, or fluororesin (e.g., PTFE, PFA, FEP, ETFE).

[0480] As shown in Figure 47, when the expansion section 320 takes a third state in which both the distal basket 341 and the proximal basket 321 are expanded, it is preferable that the traction member 361 moves proximal to the shaft 302, causing the expansion section 320 to transition in the order of the first state, second state, and third state. First, it transitions from the first state (Figure 45) to the second state (Figure 46), and as the proximal basket 321 expands, the proximal basket 321 comes into contact with the body tissue, thus fixing the catheter 301 inside the body. Then, it transitions to the third state (Figure 47), and displacement inside the body can be prevented not only by the proximal basket 321 but also by the distal basket 341. Furthermore, if the distal basket 341 has a cauterizing electrode, cauterization can be performed by the cauterizing electrode of the distal basket 341 while preventing displacement inside the body of the catheter 301 with at least the proximal basket 321, thus facilitating cauterization. Therefore, by setting the expansion order of the baskets in this way, operations such as cauterization become easier to perform.

[0481] As shown in Figures 49 to 50, the catheter 301 may have a first connection portion 371 to which the distal end of the traction member 361 and the distal end of the distal basket 341 are connected. With this configuration, the distal basket 341 can be expanded or contracted by moving the traction member 361 distally or proximal. As shown in Figure 49, it is preferable that the distal end of the traction member 361 and the plurality of second wires 342 constituting the distal basket 341 are connected to each other at the first connection portion 371.

[0482] The connection method at the first connection part 371 can include methods such as welding, silver brazing, soldering, crimping, bonding with adhesive, engagement, fitting, linking, bundling, and other physical fixing methods, or combinations thereof. At least one of these methods can also be used when connecting the second connection part 372, the third connection part 373, the fourth connection part 374, and at least two other elements, as described later. Here, "connection" includes both a form in which at least two elements are directly connected and a form in which at least two elements are indirectly connected via one or more other elements.

[0483] In the first connection part 371, the traction member 361 and the second wire 342 may or may not be in contact with each other.

[0484] As shown in FIGS. 49 to 50, in the first connection part 371, the traction member 361 and a plurality of second wires 342 may be connected by the tip chip 364. The shape of the tip chip 364 is not particularly limited, but the tip chip 364 may have one or more insertion ports into which the distal ends of the plurality of second wires 342 and / or the traction member 361 are inserted in at least a part of the longitudinal direction x of the shaft 302. For example, in FIG. 49, the tip chip 364 has a first insertion port 364m into which the distal end of the traction member 361 is inserted and a second insertion port 364n into which the distal ends of the plurality of second wires 342 are inserted.

[0485] In the radial direction y of the shaft 302, it is preferable that the second insertion port 364n is arranged more outward than the first insertion port 364m. In the radial direction y of the shaft 302, it is preferable that the first insertion port 364m is arranged so as to overlap with the central axis in the longitudinal direction x of the shaft 302.

[0486] The recess provided in the outer part in the radial direction y of the tip chip 364 may be the second insertion port 364n. The tip chip 364 may have an outer cylinder part and an inner cylinder part, and the space between the outer cylinder part and the inner cylinder part may be the second insertion port 364n. One or more second insertion ports 364n may be provided.

[0487] The tip chip 364 can be made of the same material as at least one of the first wire 322, the second wire 342, the traction member 361, and the shaft 302.

[0488] As shown in Figures 49 to 50, the catheter 301 may have a cylindrical member 365 positioned distal to the distal end of the shaft 302 and proximal to the first connection portion 371, with a traction member 361 inserted into the lumen 66c of the cylindrical member 365, and a second connection portion 372 to which the proximal end of the distal basket 341 is connected to the cylindrical member 365. With this configuration, when the traction member 361 moves distally or proximal, the cylindrical member 365 moves relative to the traction member 361, and the distance from the first connection portion 371 to the second connection portion 372 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the distal basket 341.

[0489] The cylindrical member 365 is a member for binding the first wire 322 of the proximal basket 321 and the second wire 342 of the distal basket 341. The cylindrical member 365 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 365 is movable distally or proximal relative to the traction member 361. It is preferable that the cylindrical member 365 is not fixed to the traction member 361.

[0490] The cylindrical member 365 can be made of the same material as at least one of the first wire 322, the second wire 342, the traction member 361, the shaft 302, and the tip 364.

[0491] As shown in Figure 49, it is preferable that a first insertion opening 365m is provided on the outer side of the cylindrical member 365 in the radial direction y, into which the proximal end of the second wire 342 of the distal basket 341 is inserted. The second wire 342 is inserted into the first insertion opening 365m, and the cylindrical member 365 may be crimped from the outside. The recess provided on the outer side of the cylindrical member 365 in the radial direction y may be the first insertion opening 365m. The cylindrical member 365 may have an outer cylinder and an inner cylinder, and the space between the outer cylinder and the inner cylinder may be the first insertion opening 365m. It is preferable that the first insertion opening 365m is located radially outward in the y direction from the lumen 365c of the cylindrical member 365.

[0492] Although not shown in the diagram, the second wire 342 can be connected to any part of the cylindrical member 365, as long as it does not obstruct the movement of the traction member 361. For example, the second connection portion 372 may be formed by joining the second wire 342 to the outer surface of the cylindrical member 365.

[0493] As shown in Figures 49 to 50, the catheter 301 may have a third connection portion 373 to which the distal end of the proximal basket 321 is connected to the cylindrical member 366. This configuration allows the proximal basket 321 to expand or contract as the traction member 361 moves distally or proximal. Preferably, the distal end of the traction member 361 and the multiple first wires 322 constituting the proximal basket 321 are connected to each other at the third connection portion 373.

[0494] In the third connection section 373, the distal end of the proximal basket 321 can be connected to the cylindrical member 365 in the same manner as in the second connection section 372, except that the part of the wire being connected is either the distal or proximal end. Figure 49 shows an example in which the cylindrical member 365 has a second insertion port 365n into which the distal end of the proximal basket 321 is inserted.

[0495] In the cylindrical member 365, it is preferable that the second insertion opening 365n is located distal to the first insertion opening 365m. By arranging the first insertion opening 365m and the second insertion opening 365n in this way, the two baskets are more likely to overlap over a wide area.

[0496] As shown in Figures 49 to 50, the catheter 301 may have a fourth connection portion 374 to which the proximal end of the proximal basket 321 and the distal end of the shaft 302 are connected. With this configuration, as the traction member 361 moves distally or proximal, the proximal basket 321 curves and / or bends, and the distance from the third connection portion 373 to the fourth connection portion 374 in the longitudinal direction x becomes longer or shorter, thereby enabling expansion or contraction of the proximal basket 321. Preferably, the first wire 322 and the shaft 302 constituting the proximal basket 321 are connected to each other at the fourth connection portion 374.

[0497] In the fourth connection section 374, the proximal end of the proximal basket 321 can be connected to the distal end of the shaft 302 in the same manner as in the second connection section 372. Figure 49 shows an example in which the shaft 302 has an insertion opening 302f into which the proximal end of the first wire 322 is inserted. It is preferable that the multiple first wires 322 are not fixed to the traction member 361 in the fourth connection section 374.

[0498] As shown in Figure 49, in the longitudinal direction x, the distal end of the insertion port 302f of the shaft 302 may be at the same position as the distal end of the lumen 302c of the shaft 302. In the longitudinal direction x, the distal end of the insertion port 302f of the shaft 302 may be located proximal to the distal end of the lumen 302c. In the radial direction y, it is preferable that the insertion port 302f is positioned outward from the lumen 302c.

[0499] Although not shown in the figures, the first wire 322 and the cylindrical member 365 may be in contact when the proximal basket 321 is in its most expanded state, and the inner surface of the proximal basket 321 in the radial direction y may be in contact with the proximal end of the cylindrical member 365.

[0500] As can be seen from Figure 49, it is preferable that the cylindrical member 365 and the tip 364 are in contact when the distal basket 341 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 365 and the proximal end of the tip 364 are in contact.

[0501] As can be seen from Figure 48, it is preferable that the cylindrical member 365 and the second wire 342 are in contact when the distal basket 341 is in its most expanded state, and it is more preferable that the distal end of the cylindrical member 365 and the inner surface of the distal basket 341 in the radial direction y are in contact.

[0502] Although not shown in the diagram, when the proximal basket 321 is in its most expanded state, the cylindrical member 365 and the shaft 302 may be in contact, or the proximal end of the cylindrical member 365 and the distal end of the shaft 302 may be in contact.

[0503] As shown in Figures 45 to 51, it is preferable that the second connection portion 372 is located proximal to the third connection portion 373 in the longitudinal direction x. This makes it possible to obtain a catheter in which the total length of the proximal basket 321 and the distal basket 341 is shorter than that of the catheter shown in Figure 52. Also, if electrodes are placed on both baskets, it becomes easier to reduce the distance between the electrodes. If both electrodes on each basket are used as ablation electrodes, the energy density when current is passed between the electrodes can be increased, and the ablation procedure can be performed efficiently.

[0504] As shown in Figure 52, in the longitudinal direction x, the second connection portion 372 may be located distal to the third connection portion 373. This makes it possible to obtain a catheter in which the total length of the proximal basket 321 and the distal basket 341 is longer than that of the catheters shown in Figures 45 to 51.

[0505] As can be seen from Figure 54, it is preferable that the distal basket 341 and the proximal basket 321 move relative to each other when both are in their most expanded state. Since the position of the proximal basket 321 relative to the distal basket 341 can be changed, the electrode position can be adjusted to suit the shape of the patient's pulmonary veins.

[0506] In the catheter 301 shown in Figures 52 to 53, an example is shown in which the distal end of the proximal basket 321 and the proximal end of the distal basket 341 are connected to the same cylindrical member 365. However, in order to configure the two baskets to move relative to each other, as shown in Figure 54, the distal end of the proximal basket 321 may be connected to the first cylindrical member 368 and the proximal end of the distal basket 341 may be connected to the second cylindrical member 369. In that case, it is preferable that the second cylindrical member 369 is inserted through the lumen of the first cylindrical member 368, a traction member 361 is inserted through the lumen of the second cylindrical member 369, and that the first cylindrical member 368 and the second cylindrical member 369 are each movable in the longitudinal direction x of the traction member 361. It is preferable that the second cylindrical member 369 extends to the proximal part of the catheter 301 (for example, the handle part 305) or is connected to a long member that extends to the proximal part of the catheter 301 (for example, the handle part 305). By moving the second cylindrical member 369 or the elongated member relative to the first cylindrical member 368, the distal basket 341 and the proximal basket 321 can be moved relative to each other.

[0507] For further details regarding the configuration of the first cylindrical member 368 and the second cylindrical member 369, please refer to the description of the cylindrical member 365.

[0508] Other basket expansion mechanisms will be described with reference to Figures 55 and 56. If the shaft 302 has a lumen 302c extending in the longitudinal direction x, the catheter 301 may further include a traction member 361 that extends in the longitudinal direction x, is connected to at least one of the proximal basket 321 and the distal basket 341, is inserted into the lumen 302c of the shaft 302 and is movable in the longitudinal direction x relative to the shaft 302, a first connection portion 371 to which the distal end of the traction member 361 and the distal end of the distal basket 341 are connected, and a cylindrical member 366 positioned distal to the distal end of the shaft 302 and proximal to the first connection portion 371, the traction member 361 being inserted into the lumen of the cylindrical member 366 and the cylindrical member 366 being movable in the longitudinal direction of the traction member 361. In this case, it is preferable that the distal end of the proximal basket 321 is connected to the cylindrical member 366, and the proximal end of the distal basket 341 is connected to the proximal end of the proximal basket 321 and the distal end of the shaft 302. With this configuration, by moving the traction member 361 towards the proximal side, the proximal basket 321 and the distal basket 341 curve or bend, and the distance from the first connection part 371 to the distal end of the shaft 302 in the longitudinal direction x, and the distance from the distal end of the proximal basket 321 to the distal end of the shaft 302 in the longitudinal direction x, are shortened. In this way, the proximal basket 321 and the distal basket 341 can be sequentially expanded by pulling the traction member 361.

[0509] For the configuration of the first connection part 371 shown in Figures 55 to 56, please refer to the explanation of the first connection part 371 shown in Figures 49 to 50.

[0510] The cylindrical member 366 is a member for securing the first wire 322 of the proximal basket 321. The cylindrical member 366 can be formed in any cylindrical shape, such as a cylindrical or polygonal cylindrical shape. It is preferable that the cylindrical member 366 is movable distally or proximal to the traction member 361. It is preferable that the cylindrical member 366 is not fixed to the traction member 361.

[0511] The cylindrical member 366 can be made of the same material as at least one of the first wire 322, the second wire 342, the traction member 361, the shaft 302, and the tip 364.

[0512] For information on how to connect the distal end of the proximal basket 321 to the cylindrical member 366, please refer to the description of the third connection part 373 shown in Figures 49 to 50.

[0513] For information on how to connect the proximal end of the distal basket 341, the proximal end of the proximal basket 321, and the distal end of the shaft 302, please refer to the description of the fourth connection part 374 shown in Figures 49 to 50.

[0514] Referring to Figure 57, further expansion mechanisms of the basket will be described. The shaft 302 has a lumen 302c extending in the longitudinal direction x, and the catheter 301 extends in the longitudinal direction x and is connected to at least one of the proximal basket 321 and the distal basket 341, and is inserted into the lumen 302c of the shaft 302 and has a traction member 361 that is movable in the longitudinal direction x relative to the shaft 302, the traction member 361 having a cylindrical outer member 362 and an inner member 363 disposed within the outer member 362 and movable in the longitudinal direction relative to the outer member 362, the distal end of the proximal basket 321 may be connected to the distal end of the outer member 362, and the distal end of the distal basket 341 may be connected to the distal end of the inner member 363. The distal basket 341 can be expanded by the inner member 363 moving proximal, causing the distal basket 341 to curve and / or bend. Furthermore, as the outer member 362 moves proximal, the proximal basket 321 curves and / or bends, thereby allowing the proximal basket 321 to expand. By configuring the traction member 361 in this way, it becomes easy to expand and contract the proximal basket 321 and the distal basket 341 independently.

[0515] The inner member 363 may have a hollow shape, but it is preferable that it has a solid shape.

[0516] The outer member 362 preferably has a lumen through which the inner member 363 can be inserted.

[0517] It is preferable that the inner member 363 and the outer member 362 are movable in the longitudinal direction x relative to the shaft 302. It is preferable that the inner member 363 and the outer member 362 extend to the proximal portion of the shaft 302.

[0518] The inner member 363 and the distal end of the distal basket 341 may be connected by the tip 65 shown in Figure 48. For details on the connection between the inner member 363 and the distal basket 341, please refer to the description of the first connection part 371 shown in Figure 48, etc.

[0519] The connection between the outer member 362 and the proximal basket 321 can be described by referring to the explanation of the connection between the cylindrical member 365 and the proximal basket 321 (for example, the third connection part 373) shown in Figure 48, etc.

[0520] The proximal end of the distal basket 341 is preferably connected to the outer member 362. For the connection between the distal basket 341 and the outer member 362, refer to the description of the connection between the cylindrical member 365 and the distal basket 341 (for example, the second connection part 372) shown in Figure 48, etc.

[0521] The proximal end of the proximal basket 321 is preferably connected to the distal end of the shaft 302. For the connection between the proximal basket 321 and the shaft 302, refer to the description of the connection between the proximal basket 321 and the shaft 302 (for example, the fourth connection part 374) shown in Figure 48, etc.

[0522] As shown in Figure 58, when viewing the catheter 301 from distal to proximal, it is preferable that the first wire 322 and the second wire 342 are arranged alternately in the circumferential direction. It is preferable that the first wire 322 and the second wire 342 are arranged alternately in the circumferential direction when both the distal basket 341 and the proximal basket 321 are at their most expanded state. It is also preferable that the first wire 322 and the second wire 342 are arranged alternately in the circumferential direction when both the distal basket 341 and the proximal basket 321 are at their most contracted state.

[0523] As shown in Figure 59, it is preferable that the first wire 322 and the second wire 342 are arranged to overlap when the catheter 301 is viewed from the distal to the proximal end. In this case, a part of the first wire 322 and a part of the second wire 342 may overlap each other in the circumferential direction, or the entire first wire 322 may overlap with the second wire 342.

[0524] As shown in Figure 58, it is preferable that the first wire 322 and the second wire 342 are separated when both the distal basket 341 and the proximal basket 321 are at their most expanded state. It is also preferable that the first wire 322 and the second wire 342 are separated in the first portion when both the distal basket 341 and the proximal basket 321 are at their most expanded state. It is preferable that the first wire 322 and the second wire 342 are separated in the second portion 352 when both the distal basket 341 and the proximal basket 321 are at their most expanded state. When both the distal basket 341 and the proximal basket 321 are at their most expanded state and are each divided into an outer portion and an inner portion in the radial direction y, it is preferable that the outer portion of the distal basket 341 and the outer portion of the proximal basket 321 are separated.

[0525] As can be seen from Figures 45 and 46, it is preferable that the first wire 322 and the second wire 342 are in contact when at least one of the distal basket 341 and the proximal basket 321 is most contracted. It is more preferable that the first wire 322 and the second wire 342, which are adjacent to each other in the circumferential direction, are in contact when at least one of the distal basket 341 and the proximal basket 321 is most contracted. It is preferable that the first wire 322 and the second wire 342 are in contact in the first portion 351 when at least one of the distal basket 341 and the proximal basket 321 is most contracted. It is preferable that the first wire 322 and the second wire 342 are separated in the second portion 352 when at least one of the distal basket 341 and the proximal basket 321 is most contracted.

[0526] As shown in Figure 48, in the third state, it is preferable that electrodes are placed in the distal basket 341 and the proximal basket 321, respectively, in the first portion 351. It is preferable that all of these electrodes are electrodes for cauterization.

[0527] Although not shown in the figures, in the third state, it is preferable that an electrode is positioned in the portion of the proximal basket 321 that is proximal to the point where the first wire 322 and the second wire 342 intersect, and distal to the portion of the proximal basket 321 with the largest outer diameter, and it is more preferable that an electrode for cauterization is positioned therein.

[0528] Although not shown in the diagram, it is preferable that, in the fully expanded state of both the distal basket 341 and the proximal basket 321, electrodes for measuring potential are arranged in the second portion 352 of the proximal basket 321 and electrodes for measuring potential are arranged in the third portion 353 of the distal basket 341.

[0529] It is preferable that the cauterizing electrode is positioned proximal to the portion of the first wire 322 where the first wire 322 and the second wire 342 intersect.

[0530] It is preferable that the cauterizing electrode is positioned distal to the portion of the first wire 322 where the first wire 322 and the second wire 342 intersect.

[0531] It is preferable that the cauterizing electrode is positioned on the side of the second wire 342 that is proximal to the portion where the first wire 322 and the second wire 342 intersect.

[0532] It is preferable that the cauterizing electrode is positioned distal to the portion of the second wire 342 where the first wire 322 and the second wire 342 intersect.

[0533] An electrode for cauterization may be placed in the portion of the first wire 322 where the first wire 322 and the second wire 342 intersect.

[0534] An electrode for cauterization may be placed in the portion of the second wire 342 where the first wire 322 and the second wire 342 intersect.

[0535] The proximal basket 321 has a plurality of first wires 322 arranged in the circumferential direction, and the distal basket 341 has a plurality of second wires 342 arranged in the circumferential direction, and it is preferable that the Young's modulus of the first wires 322 is smaller than that of the second wires 342. Because the first wires 322 are more flexible than the second wires 342, the proximal basket 321 is more likely to expand before the distal basket 341.

[0536] Young's modulus (Pa) can be measured, for example, using the following bending test method: The wire is held at both ends in the longitudinal direction, and a load is applied to the center of the wire in the longitudinal direction from a direction perpendicular to the longitudinal direction. The displacement is measured using a strain gauge or similar device, and Young's modulus is determined.

[0537] The proximal basket 321 has a plurality of first wires 322 arranged in the circumferential direction, and the distal basket 341 has a plurality of second wires 342 arranged in the circumferential direction, and it is preferable that the bending stiffness of the first wires 322 is lower than that of the second wires 342. Because the first wires 322 are more easily bent than the second wires 342, the proximal basket 321 is more likely to expand before the distal basket 341.

[0538] Bending stiffness (Pa·m) ４ The bending stiffness (m) represents the resistance of the wires that make up the basket to bending, with a lower value indicating easier bending. Bending stiffness can be measured using a bending test method, for example, by following these steps: First, determine Young's modulus using the method described above. Next, observe the shape of the cross-section perpendicular to the longitudinal direction of the wire and measure the size of each part (width, length, etc.) of the cross-section to determine the second moment of area (m ４ ) is calculated. The bending stiffness is calculated from the product of Young's modulus and the second moment of area.

[0539] The second moment of area of ​​the first wire 322 is preferably smaller than the second moment of area of ​​the second wire 342. Because the first wire 322 is more flexible than the second wire 342, the proximal basket 321 is more likely to expand before the distal basket 341.

[0540] The cross-sectional shapes of the first wire 322 and the second wire 342 perpendicular to their longitudinal directions may be the same or different.

[0541] In a first state, where the proximal basket 321 has a plurality of first wires 322 arranged in the circumferential direction, and the distal basket 341 has a plurality of second wires 342 arranged in the circumferential direction, it is preferable that in the first state, the first wires 322 are longer than the second wires 342 in the longitudinal direction x of the shaft 302. It is even more preferable that in the first state, each of the first wires 322 is longer than all of the second wires 342 in the longitudinal direction x of the shaft 302. In the first state, the longer first wires 322 make it easier for the proximal basket 321 to expand before the distal basket 341. Here, "first wires 322 are longer than second wires 342" means that the length of the longest wire among the plurality of first wires 322 is longer than the length of the longest wire among the plurality of second wires 342.

[0542] As shown in Figure 48, when both the distal basket 341 and the proximal basket 321 are in their most expanded state, it is preferable that the maximum outer diameter of the proximal basket 321 is larger than the maximum outer diameter of the distal basket 341. This makes it easier to bring the distal basket 341 into contact with the inner wall of the pulmonary vein and the proximal basket 321 into contact with the antrum of the pulmonary vein.

[0543] When both the distal basket 341 and the proximal basket 321 are fully expanded, the maximum outer diameter of the proximal basket 321 may be smaller than the maximum outer diameter of the distal basket 341. This makes it easier to use when you want to firmly fix the catheter 301 inside the body with the distal basket 341, or when the antrum of the pulmonary veins is elevated due to a lesion or the like, and a smaller outer diameter of the proximal basket 321 is preferable.

[0544] This application claims the benefit of priority based on Japanese Patent Application No. 2024-160178, filed on September 17, 2024; the benefit of priority based on Japanese Patent Application No. 2024-160179, filed on September 17, 2024; the benefit of priority based on Japanese Patent Application No. 2024-160180, filed on September 17, 2024; and the benefit of priority based on Japanese Patent Application No. 2024-160181, filed on September 17, 2024. The entire contents of the specifications of Japanese Patent Application No. 2024-160178, Japanese Patent Application No. 2024-160179, Japanese Patent Application No. 2024-160180, and Japanese Patent Application No. 2024-160181 are incorporated herein by reference.

[0545] 1: Ablation catheter 2: Shaft 11: Electrode 21: Proximal basket 22: First wire 31: Electrode 41: Distal basket 42: Second wire 61: Traction member 101: Ablation catheter 102: Shaft 111: First electrode 121: Proximal basket 122: First wire 131: Second electrode 141: Distal basket 142: Second wire 161: Traction member 191: Electrode for cauterization 192: Electrode for potential measurement 201: Catheter 202: Shaft 211: Electrode 221: Proximal basket 222: First wire 231: Electrode 241: Distal basket 242: Second wire 261: Traction member 291: Electrode for cauterization 292: Electrode for potential measurement 301: Catheter 302: Shaft 311: Electrode 321: Proximal basket 322: First wire 331: Electrode 341: Distal basket 342: Second wire 361: Traction member 391: Electrode for cauterization 392: Electrode for potential measurement x: Longitudinal direction y: Radial direction z: Circumferential direction

Claims

1. An ablation catheter comprising: a shaft having a longitudinal direction; a proximal basket having an electrode and positioned at the distal end of the shaft; and a distal basket having an electrode and positioned overlapping a portion of the proximal basket in the longitudinal direction.

2. The ablation catheter according to claim 1, wherein, in the longitudinal direction, the distal end of the proximal basket is located between the proximal end of the distal basket and the position of the maximum outer diameter of the distal basket.

3. The ablation catheter according to claim 1, wherein, in the longitudinal direction, the proximal end of the distal basket is located between the position of the maximum outer diameter of the proximal basket and the distal end of the proximal basket.

4. The ablation catheter according to claim 1, wherein, in the longitudinal direction, the proximal end of the distal basket is at the same position as the proximal end of the proximal basket.

5. The ablation catheter according to claim 1, wherein, in the state in which both the distal basket and the proximal basket are most expanded, the length of the first portion in the longitudinal direction in which the distal basket and the proximal basket overlap is longer than the length of the second portion of the proximal basket that does not overlap with the distal basket.

6. The ablation catheter according to claim 1, wherein the shaft has a lumen extending in the longitudinal direction, and the ablation catheter further comprises: a traction member extending in the longitudinal direction, connected to at least one of the proximal basket and the distal basket, inserted into the lumen of the shaft and movable in the longitudinal direction relative to the shaft; a first connection portion connecting the distal end of the traction member and the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member; a second connection portion connecting the proximal end of the distal basket and the cylindrical member; a third connection portion connecting the distal end of the proximal basket and the cylindrical member; and a fourth connection portion connecting the proximal end of the proximal basket and the distal end of the shaft.

7. The ablation catheter according to claim 1, wherein the shaft has a lumen extending in the longitudinal direction, the ablation catheter further comprises: a traction member extending in the longitudinal direction, connected to at least one of the proximal basket and the distal basket, inserted into the lumen of the shaft and movable in the longitudinal direction relative to the shaft; a first connection portion connecting the distal end of the traction member and the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member, the distal end of the proximal basket and the cylindrical member being connected, and the proximal end of the distal basket and the proximal end of the shaft being connected.

8. The ablation catheter according to claim 1, wherein the shaft has a lumen extending in the longitudinal direction, the ablation catheter further comprises a traction member extending in the longitudinal direction, connected to at least one of the proximal basket and the distal basket, inserted into the lumen of the shaft and movable in the longitudinal direction relative to the shaft, and a first connection portion to which the distal end of the traction member and the distal end of the distal basket are connected, the distal end of the proximal basket and the middle portion of the traction member in the longitudinal direction are connected, and the proximal end of the distal basket and the distal end of the shaft are connected.

9. The ablation catheter according to claim 1, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, the distal basket has a plurality of second wires arranged in the circumferential direction, and when the ablation catheter is viewed from the distal side toward the proximal side, the first wires and the second wires are arranged alternately in the circumferential direction.

10. The ablation catheter according to claim 9, wherein the first wire and the second wire are separated when both the distal basket and the proximal basket are in their most expanded state.

11. The ablation catheter according to claim 1, wherein both the electrode of the proximal basket and the electrode of the distal basket are electrodes for cauterization.

12. The ablation catheter according to claim 1, wherein, when both the distal basket and the proximal basket are in their most expanded state, the maximum outer diameter of the proximal basket is greater than the maximum outer diameter of the distal basket.

13. An ablation catheter comprising: a shaft having a longitudinal direction; a proximal basket having a first electrode for performing either ablation or electrometry and positioned distal to the shaft; and a distal basket having a second electrode for performing either ablation or electrometry and positioned distal to the proximal basket in the longitudinal direction, at least a portion of which is positioned distal to the proximal basket.

14. The ablation catheter according to claim 13, wherein, in the longitudinal direction, the distal end of the proximal basket is located more proximal to the proximal end of the distal basket.

15. The ablation catheter according to claim 13, wherein the first electrode is an electrode for cauterization, and the proximal basket is not equipped with an electrode for measuring potential.

16. The ablation catheter according to claim 15, wherein the second electrode is an electrode for measuring potential, and the distal basket does not have an electrode for cauterization.

17. The ablation catheter according to claim 13, wherein the second electrode is an electrode for cauterization, and the distal basket is not equipped with an electrode for measuring potential.

18. The ablation catheter according to claim 17, wherein the first electrode is an electrode for measuring potential, and the proximal basket does not have an electrode for cauterization.

19. The ablation catheter according to claim 13, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, the distal basket has a plurality of second wires arranged in the circumferential direction, and when the ablation catheter is viewed from the distal side toward the proximal side, the first wires and the second wires are arranged alternately in the circumferential direction.

20. The ablation catheter according to claim 13, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and when the ablation catheter is viewed from the distal side toward the proximal side, the first wires and the second wires are arranged to overlap.

21. The ablation catheter according to claim 13, wherein, when both the distal basket and the proximal basket are in their most expanded state, the maximum outer diameter of the proximal basket is greater than the maximum outer diameter of the distal basket.

22. The ablation catheter according to claim 13, wherein the distal basket and the proximal basket are each independently expandable.

23. The ablation catheter according to claim 13, further comprising a traction member extending in the longitudinal direction and connected to at least one of the proximal basket and the distal basket, and movable in the longitudinal direction relative to the shaft, wherein the shaft has a lumen extending in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the proximal basket and the distal basket expand when the traction member moves proximal to the shaft.

24. A catheter comprising: a shaft having a longitudinal direction; a proximal basket disposed at the distal end of the shaft; and a distal basket whose longitudinal direction at least a portion is disposed distal to the proximal basket, wherein at least one of the proximal basket and the distal basket has an electrode, and the expansion portion takes the following states: a first state in which both the distal basket and the proximal basket are contracted, and a second state in which the distal basket is expanded and the proximal basket is contracted.

25. The catheter according to claim 24, further comprising a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, wherein the shaft has a lumen that extends in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the expansion portion transitions from the first state to the second state by the movement of the traction member proximal to the shaft.

26. The catheter according to claim 24, wherein the expansion portion takes a third state in which both the distal basket and the proximal basket are expanded.

27. The catheter according to claim 26, further comprising a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, wherein the shaft has a lumen that extends in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the expansion portion transitions in the order of the first state, the second state and the third state by moving the traction member proximal to the shaft.

28. The catheter according to claim 25 or 27, further comprising: a first connection portion connecting the distal end of the traction member to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member; a second connection portion connecting the proximal end of the distal basket to the cylindrical member; a third connection portion connecting the distal end of the proximal basket to the cylindrical member; and a fourth connection portion connecting the proximal end of the proximal basket to the distal end of the shaft.

29. The catheter according to claim 28, wherein in the longitudinal direction, the second connection portion is located more proximal to the third connection portion.

30. The catheter according to claim 28, wherein in the longitudinal direction, the second connection portion is located distal to the third connection portion.

31. The catheter according to claim 25 or 27, further comprising: a first connection portion to which the distal end of the traction member is connected to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the cylindrical member having the traction member inserted into its lumen and being movable in the longitudinal direction of the traction member, wherein the distal end of the proximal basket is connected to the cylindrical member, and the proximal end of the distal basket is connected to the distal end of the shaft.

32. The catheter according to claim 25 or 27, wherein the traction member comprises an outer member having a cylindrical shape and an inner member disposed within the outer member and movable in the longitudinal direction relative to the outer member, the distal end of the proximal basket being connected to the distal end of the outer member, and the distal end of the distal basket being connected to the distal end of the inner member.

33. The catheter according to claim 24, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and the bending stiffness of the second wires is lower than that of the first wires.

34. The catheter according to claim 33, wherein the Young's modulus of the second wire is smaller than the Young's modulus of the first wire.

35. The catheter according to claim 24, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and in the first state, the second wires are longer than the first wires in the longitudinal direction of the shaft.

36. A catheter comprising: a shaft having a longitudinal direction; a proximal basket disposed at the distal end of the shaft; and a distal basket whose longitudinal direction at least a portion is disposed distal to the proximal basket, wherein at least one of the proximal basket and the distal basket has an electrode, and the expansion portion takes the following states: a first state in which both the distal basket and the proximal basket are contracted, and a second state in which the proximal basket is expanded and the distal basket is contracted.

37. The catheter according to claim 36, further comprising a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, wherein the shaft has a lumen that extends in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the expansion portion transitions from the first state to the second state by the movement of the traction member proximal to the shaft.

38. The catheter according to claim 36, wherein the expansion portion takes a third state in which both the distal basket and the proximal basket are expanded.

39. The catheter according to claim 38, further comprising a traction member that extends in the longitudinal direction and is connected to at least one of the proximal basket and the distal basket, and is movable in the longitudinal direction relative to the shaft, wherein the shaft has a lumen that extends in the longitudinal direction, the traction member is inserted through the lumen of the shaft, and the expansion portion transitions in the order of the first state, the second state and the third state by moving the traction member proximal to the shaft.

40. The catheter according to claim 37 or 39, further comprising: a first connection portion to which the distal end of the traction member is connected to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the traction member being inserted into the lumen of the cylindrical member and movable in the longitudinal direction of the traction member; a second connection portion to which the proximal end of the distal basket is connected to the cylindrical member; a third connection portion to which the distal end of the proximal basket is connected to the cylindrical member; and a fourth connection portion to which the proximal end of the proximal basket is connected to the distal end of the shaft.

41. The catheter according to claim 40, wherein in the longitudinal direction, the second connection portion is located more proximal to the third connection portion.

42. The catheter according to claim 40, wherein in the longitudinal direction, the second connection portion is located distal to the third connection portion.

43. The catheter according to claim 37 or 39, further comprising: a first connection portion to which the distal end of the traction member is connected to the distal end of the distal basket; a cylindrical member disposed distal to the distal end of the shaft and proximal to the first connection portion, the cylindrical member having the traction member inserted into its lumen and movable in the longitudinal direction of the traction member, wherein the distal end of the proximal basket is connected to the cylindrical member, and the proximal end of the distal basket is connected to the distal end of the shaft.

44. The catheter according to claim 37 or 39, wherein the traction member comprises an outer member having a cylindrical shape and an inner member disposed within the outer member and movable in the longitudinal direction relative to the outer member, the distal end of the proximal basket being connected to the distal end of the outer member, and the distal end of the distal basket being connected to the distal end of the inner member.

45. The catheter according to claim 36, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and the bending stiffness of the first wires is lower than that of the second wires.

46. ​​The catheter according to claim 45, wherein the Young's modulus of the first wire is smaller than the Young's modulus of the second wire.

47. The catheter according to claim 36, wherein the proximal basket has a plurality of first wires arranged in the circumferential direction, and the distal basket has a plurality of second wires arranged in the circumferential direction, and in the first state, the first wires are longer than the second wires in the longitudinal direction of the shaft.

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