Electrode catheter

Abstract

The present invention comprises a rod-shaped member 14 in which a lumen is formed, a core material 20 that is at least partially positioned in the lumen, an electric wire body 22 that is composed of a plurality of electric wires 38 spirally wound around the core material 20, and is at least partially positioned in the lumen, and a plurality of electrodes that are fixed to an outer circumerential section of the rod-shaped member 14 and are electrically connected to the electric wires 38, wherein the core material 20 and the electric wire body 22 are separated in at least a partial range in the axial direction of the rod-shaped member 14. A space can thus be secured between the core material 20 and the electric wire body 22 in the axial direction range in which the core material 20 and the electric wire body 22 are separated.

Description

Electrode catheter

[0001] The present disclosure relates to electrode catheters.

[0002] Patent Document 1 discloses an electrode catheter including a rod-shaped member in which a lumen is formed, a core material at least a portion of which is located within the lumen, an electric wire body formed of a plurality of electric wires wound spirally around the core material, and a plurality of electrodes electrically connected to the electric wires.

[0003] JP 2014-204986 A

[0004] In the technique disclosed in Patent Document 1, the electric wire body is in contact with both the rod-shaped member and the core material. The inventors of the present application recognized that there is room for improvement in the technique disclosed in Patent Document 1 in order to increase the degree of freedom in designing electrode catheters.

[0005] Therefore, one object of the present disclosure is to provide an electrode catheter that is advantageous in terms of increasing design freedom.

[0006] An electrode catheter according to one aspect of the present disclosure comprises a rod-shaped member having a lumen formed therein, a core material at least a portion of which is located within the lumen, a wire body formed of a plurality of electric wires wound helically around the core material and at least a portion of which is located within the lumen, and a plurality of electrodes fixed to the outer periphery of the rod-shaped member and electrically connected to the electric wires, and the core material and the wire body are spaced apart within at least a portion of the axial range of the rod-shaped member.

[0007] The electrode catheter of the present disclosure is advantageous in terms of increasing design freedom.

[0008] 12 is a side view showing an electrode catheter of a first embodiment. FIG. 13 is a side cross-sectional view schematically showing the electrode catheter of FIG. 1. FIG. 14 is a perspective cross-sectional view showing a portion of the electrode catheter of FIG. 1. FIG. 14 is a cross-sectional view taken along line IV-IV of FIG. 2. FIG. 15 is a cross-sectional view taken along line V-V of FIG. 2. FIG. 15 is a side cross-sectional view schematically showing the configuration around the electrode of FIG. 2. FIG. 16 is a cross-sectional view taken along line VII-VII of FIG. 2. FIG. 16 is a side cross-sectional view schematically showing the configuration around the fixing member of FIG. 2. FIG. 17 is a cross-sectional view taken along line IX-IX of FIG. 2. FIG. 18 is a side cross-sectional view showing the helical pitch of the wire body and the inner coil. FIG. 19 is a side cross-sectional view showing the distal end coil structure of the electrode catheter of FIG. 1. FIG. 19 is a side cross-sectional view of an electrode catheter of a second embodiment, viewed from the same perspective as FIG. 6. FIG. 19 is a cross-sectional view taken along line XIII-XIII of FIG. 12. FIG. 19 is a side cross-sectional view showing the covering member and its surroundings of an electrode catheter of a third embodiment.

[0009] Hereinafter, an embodiment for implementing the electrode catheter of the present disclosure will be described. The same or equivalent elements will be given the same reference numerals, and duplicate explanations will be omitted. In each drawing, for the sake of convenience, components will be omitted, enlarged, or reduced in size as appropriate. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0010] (First embodiment) See Figures 1 and 2. An electrode catheter 10 is inserted into the body for treatment or examination of a living organism. Examination here refers to, for example, electrocardiography. Treatment here refers to, for example, ablation (PFA (Pulsed Field Ablation), radiofrequency ablation, etc.), defibrillation, etc. The electrode catheter 10 of this embodiment is used, for example, for insertion into small epicardial blood vessels such as coronary veins.

[0011] The electrode catheter 10 comprises a rod-shaped member 14 having a lumen 12 formed therein, a handle 16 attached to the proximal end of the rod-shaped member 14 and grasped by the surgeon, and a distal coil structure 18 provided distal to the rod-shaped member 14. The electrode catheter 10 also comprises a core member 20 at least a portion of which is located within the lumen 12 of the rod-shaped member 14, an electric wire 22 at least a portion of which is located within the lumen 12, a plurality of electrodes 24 fixed to the outer periphery of the rod-shaped member 14, an elastic member 26 disposed between the rod-shaped member 14 and the core member 20, and a fixing member 28 fixed to the outer periphery of the rod-shaped member 14.

[0012] See Figures 2 and 3. The rod-shaped member 14 is inserted into the body and has flexibility that allows it to bend and deform. The lumen 12 of the rod-shaped member 14 extends in the axial direction of the rod-shaped member 14 (hereinafter simply referred to as the axial direction). The rod-shaped member 14 in this embodiment is a catheter shaft 30 attached to a handle 16 at its proximal end. The rod-shaped member 14 is made of a synthetic resin, such as polyether block ether, polyamide, polyolefin, or polytetrafluoroethylene, but specific examples are not particularly limited. The rod-shaped member 14 in this embodiment has a single-layer structure, but may also have a multi-layer structure.

[0013] The core material 20 has a rod-like shape extending in the axial direction. The core material 20 has flexibility that allows it to elastically deform together with the rod-shaped member 14. The core material 20 in this embodiment has a solid structure that is solid in a cross section perpendicular to the axial direction. Alternatively, the core material 20 may have a hollow structure that is hollow in the cross section. The core material 20 is made of, for example, stainless steel, nitinol, cobalt alloy, etc. The torque transmissibility of the core material 20 is higher than that of the rod-shaped member 14. To achieve this, the modulus of rigidity (Pa) of the core material 20 is made higher than that of the rod-shaped member 14, and the polar moment of inertia of the core material 20 (mm ４ ) should be higher than the polar moment of inertia of the rod-shaped member 14.

[0014] The core material 20 is passed through the lumen 12 of the rod-shaped member 14. A portion of the core material 20 in this embodiment extends distally beyond the tip of the rod-shaped member 14 through an opening 32 formed at the tip of the rod-shaped member 14. Alternatively, the entire core material 20 may be located only within the lumen 12 of the rod-shaped member 14, or may extend proximally beyond the base end of the rod-shaped member 14.

[0015] The core material 20 and the catheter shaft 30 constitute the catheter body 34. In this embodiment, the core material 20 is provided in the axial range from the base end to the tip end of the catheter body 34 (hereinafter referred to as the axial range).

[0016] The electric wire 22 is passed through the lumen 12. The electric wire 22 has flexibility that allows it to be elastically deformed together with the rod-shaped member 14 and the core material 20. At least a portion of the electric wire 22 is located within the lumen 12 of the rod-shaped member 14. In this embodiment, the electric wire 22 is pulled out toward the proximal end through an opening (not shown) formed in the proximal end of the rod-shaped member 14, passes through the handle 16, and is electrically connected to a connector 36 provided in the handle 16. Alternatively, the entire electric wire 22 may be located only within the lumen 12 of the rod-shaped member 14.

[0017] The electric wire body 22 is composed of a plurality of electric wires 38 wound in a spiral shape around the core material 20. The spiral shape of the electric wires 38 improves the kink resistance of the electric wire body 22 compared to when the electric wires 38 are straight. The electric wire body 22 in this embodiment is composed of a total of 12 electric wires 38, but the number is not particularly limited. The plurality of electric wires 38 contact the inner circumferential surface of the rod-shaped member 14 that forms the lumen 12. The plurality of electric wires 38 include lead wires 40 made of a conductor and an insulating layer 42 made of an insulator that covers the lead wires 40.

[0018] The multiple electrodes 24 are fixed to the outer periphery of the rod-shaped member 14 at positions spaced apart in the axial direction. The electrodes 24 in this embodiment are made of ring material. Specific examples of the electrodes 24 are not limited to ring material, and may be made of a surface material or the like. The electrodes 24 are made of a metallic material with good conductivity, such as platinum, gold, silver, aluminum, copper, or stainless steel. The metallic material may be made of only the main metal, or may be made of an alloy containing the main metal as a main component.

[0019] At least one corresponding electric wire 38 is electrically connected to each electrode 24. In this embodiment, a single corresponding electric wire 38 is electrically connected to each electrode 24, but multiple corresponding electric wires 38 may also be electrically connected to each electrode 24. In this embodiment, a total of 12 electrodes 24 are provided corresponding to a total of 12 electric wires 38, but the number is not particularly limited.

[0020] The multiple electrodes 24 are electrically connected to an external electrical device via connectors 36 and electric wires 38. The electrodes 24 are used to acquire electrical signals emitted by a living body for measurements such as cardiac potential measurement. In this case, the electrical signals acquired by the electrodes 24 are transmitted to an external measuring device (external electrical device) via the electric wires 38 corresponding to the electrodes 24 and used for processing for measurement by the external measuring device. In addition, the electrodes 24 may be used to output electricity to be used for treatment of a living body, such as for ablation. In this case, electricity to be output from the electrodes 24 is supplied from an external power supply device (external electrical device) via the electric wires 38 corresponding to the electrodes 24.

[0021] The elastic member 26 of this embodiment includes an inner coil 44 that is wound helically around the core member 20. At least a portion of the inner coil 44 is located within the lumen 12 of the rod-shaped member 14. Axial gaps 46 are provided between adjacent portions of the wire that constitute the inner coil 44 of this embodiment.

[0022] The elastic member 26 is arranged at least in a certain axial range of the electrode 24. The elastic member 26 in this embodiment is arranged in an axial range that includes each of the multiple electrodes 24. Alternatively, an individual elastic member 26 may be arranged in a certain axial range of each of the multiple electrodes 24. The base end 26a of the elastic member 26 in this embodiment is located between the electrode 24 and the fixing member 28 in the axial direction. The elastic member 26 in this embodiment is arranged between the electric wire 22 and the core material 20 within the lumen 12 of the rod-shaped member 14. Alternatively, the elastic member 26 may be arranged between the rod-shaped member 14 and the electric wire 22.

[0023] The fixing member 28 is fixed to the rod-shaped member 14 on the proximal side of the most proximal electrode 24 among the plurality of electrodes 24. In this embodiment, the fixing member 28 is made of a ring material. Specific examples of the fixing member 28 are not limited to a ring material, and the fixing member 28 may be made of a wire material or the like. The fixing member 28 is made of, for example, a metal material, a resin material, or the like. The electric wire 38 is not electrically connected to the fixing member 28.

[0024] In this embodiment, there are multiple fixing members 28, but the number is not particularly limited. The multiple fixing members 28 are fixed to the rod-shaped member 14 at intervals in the axial direction in the axial range from the proximal end side of the multiple electrodes 24 to the handle 16.

[0025] The core material 20 includes a tapered portion 50 that gradually narrows toward the distal end, and a straight portion 52 that is provided closer to the proximal end than the tapered portion 50. In FIG. 2, for ease of explanation, the outer diameter of the tapered portion 50 of the core material 20 is exaggerated to show an increase at some boundary lines, and the change in outer diameter is omitted in other locations. In FIG. 2, for ease of explanation, a dashed line is drawn at the boundary between the tapered portion 50 and the straight portion 52. The straight portion 52 extends straight toward the axial direction of the rod-shaped member 14 and is formed to have an outer diameter that is uniform along the axial direction. Here, "uniform" includes the concept of being identical or substantially identical.

[0026] The tapered section 50 is provided in at least a portion of the axial range of the core material 20. When providing the tapered section 50 in the core material 20, the tapered sections 50 and straight sections 52 may be present alternately. For example, from the base end side to the tip end side of the core material 20, the straight section 52, the tapered section 50, the straight section 52, and the tapered section 50 may be present in this order.

[0027] The tapered section 50 in this embodiment is provided in at least a part of the distal end 34a of the catheter main body 34, but is not provided in the portion closer to the base end than the distal end. Here, the distal end 34a of the catheter main body 34 refers to, for example, a location that is one-fifth of the total axial length of the catheter main body 34 from the distal end of the catheter main body 34. A straight section 52 of the core material 20 is provided in the portion closer to the base end than the distal end 34a of the catheter main body 34.

[0028] The tapered portion 50 is provided in a certain axial range of at least one electrode 24. Here, "a certain axial range of at least one electrode 24" may be, for example, an axial range that includes two or more electrodes 24 that are arranged in order in the axial direction out of all of the electrodes 24. This axial range that includes two or more electrodes 24 may be an axial range that includes all of the electrodes 24. Alternatively, "an axial range that includes at least one electrode 24" may be an axial range that includes only one electrode 24. In this embodiment, a tip side portion of the tapered portion 50 that is located distal to the axial center position is provided in an axial range that includes all of the electrodes 24.

[0029] The straight portion 52 is provided in a certain axial range of at least one fixing member 28. Here, "a certain axial range of at least one fixing member 28" may be, for example, an axial range that includes two or more fixing members 28 that are arranged in order in the axial direction out of all of the fixing members 28. This axial range that includes two or more fixing members 28 may be an axial range that includes all of the fixing members 28. Alternatively, "an axial range of at least one fixing member 28" may be an axial range that includes only one fixing member 28. The outer diameter of the core material 20 in a certain axial range of the electrode 24 is smaller than the outer diameter of the core material 20 in a certain axial range of the fixing member 28.

[0030] See Figures 2, 4, and 5. In Figures 4 and 5, the location of the elastic member 26 is indicated by a two-dot chain line. A gap 60 is provided between the wire body 22 and the core material 20 in at least a portion of the axial range of the rod-shaped member 14. In the axial range where the gap 60 is provided, the wire body 22 is not in contact with the core material 20. In this embodiment, the gap 60 is provided between the wire body 22 and the core material 20 in at least a portion of each of the following: a first axial range R1 between the tip of the rod-shaped member 14 and the tip-most electrode 24; a second axial range R2 between axially adjacent electrodes 24; a third axial range R3 between axially adjacent electrodes 24 and the fixing member 28; a fourth axial range R4 between axially adjacent fixing members 28; and a fifth axial range (omitted) between the base-most fixing member 28 of the rod-shaped member 14 and the base end of the rod-shaped member 14. This means that no gap 60 is provided between the core material 20 and the wire body 22 in certain axial ranges of each of the electrode 24 and the fixing member 28. Alternatively, the wire body 22 may be provided with the gap 60 provided between it and the core material 20 over the entire axial range.

[0031] To satisfy the condition that the gap 60 is provided in the axial range of at least a portion of the rod-shaped member 14, the gap 60 may be provided in at least one of the axial ranges R1 to R5 (for example, the second axial range R2). Furthermore, to satisfy the condition that the gap 60 is provided in the axial range of at least a portion of the rod-shaped member 14, the gap 60 may be provided in the second axial range R2. To satisfy the condition that the gap 60 is provided in the second axial range R2 here, it is sufficient that the gap 60 is provided in a range spanning a portion or the entire length of the second axial range R2. The same applies to satisfying the condition that the gap 60 is provided in the other axial ranges R1, R3 to R5.

[0032] The gap 60 is formed between adjacent members in the radial direction of the core material 20 (hereinafter simply referred to as the radial direction). When no other member is disposed between the core material 20 and the wire body 22, the gap 60 is formed between the core material 20 and the wire body 22 that are adjacent in the radial direction. Here, the "other member" refers to, for example, the elastic member 26 described above. In this embodiment, for example, as shown in FIG. 5 , in the fourth axial range R4 described above, no other member is disposed between the core material 20 and the wire body 22, and the gap 60 is formed between the core material 20 and the wire body 22 that are adjacent in the radial direction. In addition to the fourth axial range R4, the gap 60 is also formed in a fifth axial range, etc.

[0033] In contrast, when another member is disposed between the core material 20 and the wire body 22, the gap 60 is formed between at least one of (1) another radially adjacent member and the core material 20, (2) another radially adjacent member and the wire body 22, and (3) multiple radially adjacent members. In this embodiment, for example, as shown in FIG. 4 , an elastic member 26 is disposed between the core material 20 and the wire body 22 in the second axial range R2, and a gap 60 is formed between each of the aforementioned (1) and (2). This gap 60 is also formed in the first axial range R1, etc., in addition to the second axial range R2. When another member is disposed between the core material 20 and the wire body 22, the other member is referred to as a first member, and members adjacent to the first member on both radial sides are referred to as second members. In this case, the entire space existing between two second members, including the first member, is treated as not being the gap 60. In this case, the space formed between the radially adjacent members is treated as the gap 60. By forming a gap 60 between the inner coil 44 and the core material 20, the inner coil 44 can be deformed so as to reduce its diameter, thereby becoming elastically deformable radially inward of the core material 20.

[0034] The gap 60 is provided to absorb dimensional variations of the electric wire 38. More specifically, the gap 60 is provided to absorb an increase in the outer diameter of the electric wire 38 when the outer diameter of the electric wire 38 increases so as to approach the core material 20 due to dimensional variations of the electric wire 38. In the case where another member is disposed between the core material 20 and the electric wire body 22, when the outer diameter of the electric wire 38 increases so as to approach the core material 20, the increase in the outer diameter of the electric wire 38 may be absorbed by using the gap 60 between the other member and the core material 20, accompanied by deformation of the other member.

[0035] The gap 60 may be provided to absorb an increase in the outer diameter of at least one of the plurality of electric wires 38. To satisfy this condition, the gap 60 may be provided on a radius line L1 that passes through the center line C38 of the electric wire 38 and extends from the center line C20 of the core material 20 in a cross section perpendicular to the axial direction of the rod-shaped member 14. To absorb dimensional variations among the plurality of electric wires 38, the gap 60 may be provided on a radius line (not shown) corresponding to each electric wire 38. The gap 60 in this embodiment is provided to absorb dimensional variations among all of the electric wires 38, and is continuous in a ring shape around the core material 20.

[0036] The core material 20 and the wire body 22 are spaced apart in at least a portion of the axial range. It can also be said that the core material 20 and the wire body 22 are not in contact with each other in this axial range. The axial range that satisfies this condition is not particularly limited. In this embodiment, the core material 20 and the wire body 22 are spaced apart in an axial range other than a certain axial range of the fixing member 28. The core material 20 and the wire body 22 are spaced apart in a certain axial range of the electrode 24, and are also spaced apart in each of the axial ranges R1 to R4 described above. Alternatively, the wire body 22 and the core material 20 may be spaced apart in all axial ranges.

[0037] The effects of the electrode catheter 10 in relation to the features described above will now be described.

[0038] The core material 20 and the wire body 22 are separated from each other in at least a portion of the axial range. This ensures a space between the core material 20 and the wire body 22 in the axial range where the core material 20 and the wire body 22 are separated from each other. This space allows various components to be arranged, which is advantageous in terms of increasing design freedom. Furthermore, if the core material 20 is conductive, this is advantageous in terms of avoiding unintended conduction between the core material 20 and the wire body 22.

[0039] A gap 60 is provided between the wire body 22 and the core material 20. Therefore, even if the dimensions of the wires 38 increase from a predetermined standard outer diameter due to dimensional variations of the wires 38, the gap 60 can absorb the dimensional increase. This makes it possible to prevent the wires 38 from being pinched between the rod-shaped member 14 and the core material 20 due to dimensional variations of the wires 38 in the axial range where the gap 60 is located, thereby preventing a compressive load from being applied to the wires 38. Alternatively, even if the wires 38 are pinched between the rod-shaped member 14 and the core material 20, the compressive load applied to the wires 38 can be reduced compared to when there is no gap 60 between the wire body 22 and the core material 20. Consequently, even if the dimensions of the wires 38 vary, the compressive load applied to the wires 38 can be reduced. This reduction in compressive load stabilizes the insulation between the plurality of wires 38. In addition, the reduction in the risk of wire breakage in the electric wire 38 is advantageous in improving the product yield.

[0040] The core material 20 includes a tapered portion 50. This allows the tapered portion 50 of the core material 20 to bend and deform more easily to follow a tortuous biological organ such as a blood vessel than if the tapered portion 50 of the core material 20 were a straight portion having an outer diameter equal to the maximum outer diameter of the tapered portion 50. This improves the trackability of the catheter main body 34 including the core material 20. Furthermore, this improves the transmission of axial force from the proximal end of the tapered portion 50 to the distal end than if the tapered portion 50 of the core material 20 were a straight portion having an outer diameter equal to the minimum outer diameter of the tapered portion 50. This improves the pushability of the catheter main body 34. In other words, this is advantageous in improving the trackability and pushability of the catheter main body 34.

[0041] The tapered portion 50 of the core material 20 is provided in a certain axial range of at least one electrode 24. Therefore, in a certain axial range of both the electrode 24 and the tapered portion 50 of the core material 20, it is easier to widen the gap between the rod-shaped member 14 and the core material 20 compared to a case where the outer diameter of the core material 20 is the maximum outer diameter of the tapered portion 50. This makes it possible to easily arrange the elastic member 26 between the rod-shaped member 14 and the core material 20.

[0042] The elastic member 26 is provided only in at least a portion of the axial range of the tapered portion 50 of the core material 20, and is not provided in the axial range of the straight portion 52 of the core material 20. The elastic member 26 is provided in the axial range of at least one electrode 24, but is not provided in the axial range of at least one fixing member 28. The meanings of "axial range of at least one electrode 24" and "axial range of at least one fixing member 28" here are the same as those described above. This shortens the axial length required for the elastic member 26 compared to when the elastic member 26 is provided in the axial range including the electrode 24 and fixing member 28, which is mentioned above, and is therefore advantageous for reducing component costs. The elastic member 26 in this embodiment is provided in the axial range including two or more electrodes 24 that are arranged in the axial direction out of all the electrodes 24, more specifically, in the axial range including all the electrodes 24. The elastic member 26 is not provided in the axial range including two or more fixing members 28 that are arranged in the axial direction out of all the fixing members 28, more specifically, not in the axial range including all the fixing members 28.

[0043] 6 and 7 . Another feature of the electrode catheter 10 will now be described. The electrode 24 in this embodiment is fixed to the outer periphery of the rod-shaped member 14 by being at least partially embedded in the outer periphery of the rod-shaped member 14. To achieve this, the electrode 24 in this embodiment is embedded in the outer periphery of the rod-shaped member 14 by reducing its diameter using a process such as swaging. By embedding the electrode 24 in the rod-shaped member 14, a first bulge 70 is formed on the inner periphery of the rod-shaped member 14 that forms the lumen 12 due to the plastic flow of the rod-shaped member 14. The first bulge 70 bulges out toward the core material 20 from both axial ends of the electrode 24 at the inner periphery of the rod-shaped member 14.

[0044] The rod-shaped member 14, in a certain axial range of the electrode 24, is accompanied by elastic deformation of the elastic member 26, and presses at least the elastic member 26 and the wire body 22 toward the core material 20. In this embodiment, the first bulge 70 of the rod-shaped member 14 presses the elastic member 26 and the like toward the core material 20. At this time, the wire body 22 is deformed so as to be slightly compressed radially inward of the core material 20. Also, the elastic member 26 is elastically deformed radially inward of the core material 20. Here, the inner coil 44 constituting the elastic member 26 is deformed so as to partially reduce its diameter, thereby elastically deforming the inner coil 44.

[0045] A restoring force F1 resulting from the elastic deformation of the elastic member 26 acts on the rod-shaped member 14 radially outward from the core material 20 within a certain axial range of the electrode 24. The deformation of the rod-shaped member 14 due to the restoring force F1 of the elastic member 26 and the like is restrained by the electrode 24. As a result, the rod-shaped member 14 is held by the electrode 24 within a certain axial range of the electrode 24, with the elastic deformation of the elastic member 26 accompanying the rod-shaped member 14, with at least the elastic member 26 and the electric wire 22 pressed toward the core material 20. To satisfy the condition "to press at least the elastic member 26 and the electric wire 22 toward the core material 20," it is sufficient that either one of the elastic member 26 or the electric wire 22 is located radially outward from the core material 20 and the other is located radially inward from the core material 20. Furthermore, to satisfy this condition, another member other than the elastic member 26 and the electric wire 22 may be disposed between the rod-shaped member 14 and the core material 20.

[0046] The effects of the above-described configuration around the electrode 24 will now be described. The rod-shaped member 14 is held by the electrode 24 with at least the elastic member 26 and the wire body 22 pressed against the core material 20. As a result, within a certain axial range of the electrode 24, the position of the rod-shaped member 14 relative to the core material 20 can be maintained by frictional forces acting between radially adjacent members of the core material 20. For example, in this embodiment, the frictional forces between the rod-shaped member 14 and the wire body 22, between the wire body 22 and the elastic member 26, and between the elastic member 26 and the core material 20 can suppress misalignment between them, thereby maintaining the position of the rod-shaped member 14 relative to the core material 20. In particular, the restoring force F1 of the elastic member 26 can increase the frictional force between the members between the rod-shaped member 14 and the elastic member 26, which is advantageous in suppressing misalignment between them. By maintaining the position of the rod-shaped member 14 relative to the core material 20 within a certain axial range of the electrode 24, the axial force and torque applied to the core material 20 within that axial range can be easily transmitted to the rod-shaped member 14. As a result, the axial force and torque applied to the core material 20 make it easier to apply the electrode 24 to a targeted position in biological tissue.

[0047] The electrode 24 is fixed to the rod-shaped member 14 by being at least partially embedded in the rod-shaped member 14. When the electrode 24 is embedded in the rod-shaped member 14 in this manner, an indentation load F2 acts on the rod-shaped member 14, pressing the rod-shaped member 14 radially inward into the core material 20. As a result, adjacent portions 72 adjacent to the electrode 24 on both axial sides of the outer periphery of the rod-shaped member 14 are deformed by the indentation load F2, which tends to create a large step between the adjacent portions 72 and the electrode 24. In this regard, in the present embodiment, the rod-shaped member 14 presses the elastic member 26 toward the core material 20, and a restoring force F1 of the elastic member 26 acts radially outward from the core material 20. Therefore, when the electrode 24 is embedded in the rod-shaped member 14, the restoring force F1 of the elastic member 26 makes it easier to maintain the position of the adjacent portions 72 of the rod-shaped member 14 due to the plastic flow of the rod-shaped member 14. As a result, it is possible to make it difficult for a large step to occur between the adjacent portion 72 of the rod-shaped member 14 and the electrode 24 .

[0048] The elastic member 26 is formed by the inner coil 44. As a result, by pressing the inner coil 44 and the electric wire body 22 toward the core material 20 with the rod-shaped member 14, a part of the electric wire body 22 can be wedged between axially adjacent parts of the wire that constitutes the inner coil 44. This wedged position of the electric wire body 22 can be suppressed, which is advantageous in maintaining the position of the rod-shaped member 14 relative to the core material 20.

[0049] Referring to FIG. 7 , a first side hole 74 is formed in the outer periphery of the rod-shaped member 14. The first side hole 74 penetrates the rod-shaped member 14 in the radial direction of the core material 20. A second side hole 76 is formed in the insulating layer 42 of the electric wire 38 corresponding to the electrode 24 at a position that overlaps the first side hole 74 of the rod-shaped member 14 in the radial direction of the core material 20. The second side hole 76 exposes the conductor 40 of the electric wire 38 to the outside. The first side hole 74 and the second side hole 76 are formed, for example, by irradiating the rod-shaped member 14 and the electric wire 38 with laser light to partially remove the rod-shaped member 14 and the insulating layer 42. The electric wire 38 corresponding to the electrode 24 and the electrode 24 are electrically connected by electrically connecting the conductor 40 and the electrode 24 via conductive adhesive 78 filled in each side hole 74, 76. This allows the electric wire 38 and the electrode 24 to be electrically connected without passing a portion of the electric wire 38 through the first side hole 74 of the rod-shaped member 14. Therefore, in the manufacturing process of the electrode catheter 10, the pulling step of pulling the electric wire 38 into the rod-shaped member 14 through the first side hole 74 of the rod-shaped member 14 is not required. This pulling step of the electric wire 38 is one of the factors that increases the number of steps in the manufacturing process of the electrode catheter 10. Eliminating this pulling step is advantageous in reducing the number of steps in the manufacturing process of the electrode catheter 10.

[0050] 2, 8, and 9. The fixing member 28, like the electrode 24, is fixed to the outer periphery of the rod-shaped member 14 by being at least partially embedded in the outer periphery of the rod-shaped member 14. To achieve this, the fixing member 28 in this embodiment is embedded in the outer periphery of the rod-shaped member 14 by reducing its diameter by swaging or the like. By embedding the fixing member 28 in the rod-shaped member 14, a second bulge 80 is formed on the inner periphery of the rod-shaped member 14 due to the plastic flow of the rod-shaped member 14. The second bulge 80 bulges out toward the core material 20 at the inner periphery of the rod-shaped member 14 relative to the electrode 24 on both axial sides.

[0051] The rod-shaped member 14 is held by the fixing member 28 in a state in which at least the electric wire body 22 is pressed against the core material 20 within a certain axial range of the fixing member 28. In this embodiment, the second bulge 80 of the rod-shaped member 14 presses the electric wire body 22 against the core material 20. At this time, the electric wire body 22 is deformed so as to be slightly compressed radially inward of the core material 20. In order to satisfy the condition that "at least the electric wire body 22 is pressed against the core material 20," another member other than the electric wire body 22 may be disposed between the rod-shaped member 14 and the core material 20.

[0052] As a result, within a certain axial range of the fixing member 28, the position of the rod-shaped member 14 relative to the core member 20 can be maintained by the frictional force acting between radially adjacent members of the core member 20. For example, in this embodiment, the frictional force between the rod-shaped member 14 and the wire body 22 and the frictional force between the wire body 22 and the core member 20 can suppress positional deviation therebetween, thereby maintaining the position of the rod-shaped member 14 relative to the core member 20. This is advantageous for transmitting torque between the rod-shaped member 14 and the core member 20 within a certain axial range of the fixing member 28. Therefore, when torque is input to the rod-shaped member 14 from the handle 16 or the like, the torque can be transmitted by the rod-shaped member 14 and the core member 20, improving the torque transmission of the catheter main body 34 including the rod-shaped member 14 and the core member 20.

[0053] The embedding depth La of the fixing member 28 in the rod-shaped member 14 may be smaller than the embedding depth Lb (see FIG. 6 ) of the electrode 24 in the rod-shaped member 14. Using the rod-shaped member 14 as a linearly extended state, imaginary lines L24 and L28 are assumed to extend parallel to the axial direction and contact the inner circumferential surface of the electrode 24 or fixing member 28 from the radially inner side on a cross section along the axial direction. The imaginary line L24 corresponds to the electrode 24, and the imaginary line L28 corresponds to the fixing member 28. Here, the embedding depths La and Lb refer to the radial distances from the locations where the outer diameter does not change in the axial direction at adjacent locations 72 adjacent to both axial sides of the electrode 24 or fixing member 28 to the imaginary lines L24 and L28 corresponding to the electrode 24 or fixing member 28. This reduces the number of steps required for embedding the fixing member 28 by processing such as swaging.

[0054] Referring to FIG. 10 , the helical pitch P1 of the electric wire body 22 is greater than the helical pitch P2 of the inner coil 44. Here, the helical pitch P1 refers to the distance traveled in the axial direction when the helix formed by the electric wire 38 constituting the electric wire body 22 makes one revolution around the core material 20. For convenience of explanation, FIG. 10 shows the helical pitch P1 as half the size of the helical pitch P1. Furthermore, the helical pitch P2 refers to the distance traveled in the axial direction when the helical pitch formed by the wire constituting the inner coil 44 makes one revolution around the core material 20. When the helical pitch P2 of the inner coil 44 varies in the axial direction, the maximum value of the helical pitch P2 of the inner coil 44 is used for comparison with the helical pitch P1. By satisfying the above-described conditions for the helical pitches P1 and P2, the angle of the electric wire 38 with respect to a plane perpendicular to the axial direction becomes gentler than when the helical pitch P1 is equal to or less than the helical pitch P2, making it easier to transmit an axial force using the electric wire body 22. The wire body 22 exists over a wide axial range, such as from the base end of the rod-shaped member 14 to the location of the electrode 24. By using such a wire body 22, it becomes possible to effectively transmit axial force from the base end of the rod-shaped member 14 to the location of the electrode 24. The relationship of helical pitch P1 > helical pitch P2 may be satisfied over a partial axial range of the wire body 22, or over the entire axial range of the wire body 22. The relationship between the helical pitches P1 and P2 is not particularly important. For example, the helical pitch P1 may be equal to or less than the helical pitch P2.

[0055] Please refer to Figure 11. The wire body 22 is omitted from Figure 11. The distal coil structure 18 of the electrode catheter 10 includes a distal member 90 attached to the distal end of the core member 20 on the distal side of the distal end of the rod-shaped member 14, and coils 44, 92, at least portions of which are provided between the distal member 90 and the rod-shaped member 14. At least portions of the coils 44, 92 are provided on the distal side of the rod-shaped member 14.

[0056] The tip member 90 in this embodiment is made of solder. Alternatively, the tip member 90 may be made of a metal material other than solder, such as silver, gold, or stainless steel, or a resin material. The tip surface of the tip member 90 in this embodiment is hemispherical. The tip end of the core 20 and the tip ends of the coils 44 and 92 are fixed to the tip member 90. In this embodiment, the core 20 and other components are fixed to the tip member 90 using solder. Specifically, this is achieved by embedding a portion of each component within the solder that constitutes the tip member 90. The manner in which the core 20 and other components are fixed to the tip member 90 is not particularly limited, and the core 20 and other components may be fixed to the tip member 90 using solder, adhesive, welding, or other components that are separate from the tip member 90.

[0057] The coils 44, 92 are wound helically around the core member 20. The coils 44, 92 provided between the tip member 90 and the rod-shaped member 14 include the inner coil 44 described above, as well as an outer coil 92 surrounding the inner coil 44. The coils 44, 92 are elastically bendable together with the core member 20. The coils 44, 92 are made of a metallic material primarily containing, for example, platinum, gold, tungsten, stainless steel, or the like, but the material is not particularly limited. For example, the inner coil 44 may be made of stainless steel, and the outer coil 92 may be made of a platinum-based alloy such as Pt—W.

[0058] The proximal end of the outer coil 92 and a portion of the inner coil 44 are fixed to the distal end of the rod-shaped member 14. In this embodiment, these are fixed to the rod-shaped member 14 using an adhesive 94. Here, the area where the adhesive 94 may be present is indicated by a two-dot chain line. The adhesive 94 is filled into the lumen 12 at the distal end of the rod-shaped member 14. A portion of the inner coil 44 is embedded inside this adhesive 94, thereby fixing the inner coil 44 to the rod-shaped member 14. Furthermore, a portion of this adhesive 94 protrudes from the lumen 12 of the rod-shaped member 14 toward the distal end, and a portion of the outer coil 92 is embedded inside this protruding portion, thereby fixing the outer coil 92 to the rod-shaped member 14. The manner in which the coils 44, 92 are fixed to the rod-shaped member 14 is not particularly limited, and soldering, welding, etc. may be used.

[0059] The inner coil 44 in this embodiment extends toward the proximal end beyond the proximal end 92a of the outer coil 92. In other words, the inner coil 44 is provided so as to axially straddle the proximal end 92a of the outer coil 92. The inner coil 44 in this embodiment is located within the lumen 12 of the rod-shaped member 14 from the distal end of the rod-shaped member 14 toward the proximal end.

[0060] The winding direction of the outer coil 92 is opposite to the winding direction of the inner coil 44. The winding direction here refers to the circumferential direction in which the spiral of the coil advances when the spiral advances in the axial direction. For example, if the winding direction of the outer coil 92 is clockwise, the winding direction of the inner coil 44 is counterclockwise.

[0061] The effects of the above-described distal end coil structure 18 will now be described. The electrode catheter 10 includes coils 44, 92, at least a portion of which is provided between the distal end member 90 and the rod-shaped member 14. Therefore, the coils 44, 92 are advantageous in ensuring appropriate flexibility against bending in the axial range between the distal end member 90 and the rod-shaped member 14.

[0062] The coils 44, 92 provided between the tip member 90 and the rod-shaped member 14 include an inner coil 44 at least a portion of which is located within the lumen 12 of the rod-shaped member 14. Therefore, using the inner coil 44 within the lumen 12 of the rod-shaped member 14 is advantageous in ensuring appropriate flexibility against bending in the axial range between the tip member 90 and the rod-shaped member 14.

[0063] The coils 44, 92 provided between the tip member 90 and the rod-shaped member 14 include an inner coil 44 and an outer coil 92. Therefore, in the axial range between the tip member 90 and the rod-shaped member 14, the two coils 44, 92 are further advantageous in ensuring appropriate flexibility with respect to bending.

[0064] The combination of the outer coil 92, the inner coil 44, and the core 20 is called a core unit. The inner coil 44 extends further toward the base end than the base end 92a of the outer coil 92. Therefore, compared to when this condition is not met, the difference in bending rigidity of the core unit at the boundary of the base end 92a of the outer coil 92 can be reduced. As a result, the kink resistance of the core unit around the base end 92a of the outer coil 92 can be improved.

[0065] The winding directions of the outer coil 92 and the inner coil 44 are opposite to each other. As a result, when torque in the winding direction of the outer coil 92 is applied to the core unit, the torque is easily transmitted by the inner coil 44, which has the opposite winding direction, resisting the torque in a certain axial range of each coil 44, 92. On the other hand, when torque in the winding direction of the inner coil 44 is applied to the core unit, the torque is easily transmitted by the outer coil 92, which has the opposite winding direction, resisting the torque in a certain axial range of each coil 44, 92. In other words, this is advantageous in ensuring the torque transmissibility of the core unit in a certain axial range of each coil 44, 92.

[0066] Referring to Figure 2, the region from the tip of the rod-shaped member 14 to the proximal end of the electrode 24 located closest to the base end is referred to as the first region 100, and the region from the proximal end of the electrode 24 located closest to the base end of the rod-shaped member 14 is referred to as the second region 102. The core material 20 is located inside the rod-shaped member 14 throughout the entire first and second regions 100, 102. In this case, the average outer diameter A (mm) of the core material 20 in the first region 100 may be smaller than the average outer diameter B (mm) of the core material 20 in the second region 102. This makes it easier for the first region 100 of the core material 20 to bend and deform in accordance with biological organs such as blood vessels, compared to when the average outer diameter A of the core material 20 is equal to or greater than the average outer diameter B, thereby improving the trackability of the electrode catheter 10. Furthermore, compared to when the average outer diameter B of the core material 20 is equal to or less than the average outer diameter A, it is easier to transmit axial force via the second region 102 of the core material 20, thereby improving the pushability of the electrode catheter 10. In relation to this effect of improving trackability, the average outer diameter A may preferably be equal to or less than 0.05 mm.

[0067] To satisfy the condition that the average outer diameter A is smaller than the average outer diameter B, at least a portion of either the first region 100 or the second region 102 has a portion where the outer diameter decreases stepwise or continuously toward the distal end. The specific shape of the core material 20 to satisfy this condition is not particularly limited. In this embodiment, a tapered portion 50 is provided in each of the first and second regions 100, 102, and a straight portion 52 is provided proximally therefrom. Alternatively, the straight portion 52 may also be provided in the first region 100. To satisfy the condition that the average outer diameter A is smaller than the average outer diameter B, the first region 100 may have a maximum outer diameter at its proximal end and a diameter equal to or smaller than the maximum outer diameter distally, while the second region 102 may have a minimum outer diameter at its distal end and a diameter greater than the minimum outer diameter proximally therefrom.

[0068] The method for measuring the average outer diameters A and B will be described. The axial length of the first region 100 from the tip to the base end is divided into N equal parts, and a total of N positions are taken as measurement positions. The outer diameter of the core material 20 is measured at each measurement position, and the arithmetic mean of the N measured values ​​is taken as the average outer diameter A of the core material 20. The second region 102 is also measured using a similar concept, with a total of N positions being taken as measurement positions, and the arithmetic mean of the measured values ​​of the outer diameter of the core material 20 at each measurement position being taken as the average outer diameter B of the core material 20. This N is, for example, 5.

[0069] (Second embodiment) In the following embodiments, among the components described in the first embodiment, the same content as in the first embodiment may be applied to the components that are not described below.

[0070] 12 and 13 . At least one of the core material 20 and the elastic member 26 is a conductive member 108. In this embodiment, the elastic member 26 is the conductive member 108. The conductive member 108 is made of a conductive material such as metal. In this embodiment, the rod-shaped member 14 is also held by the electrode 24 with the elastic member 26 elastically deforming, pressing the wire 22 toward the core material 20. In this case, the repulsive force caused by the elastic deformation of the elastic member 26 may thin the insulating layer 42 of the wire 22. As a result, there is a risk of unintended electrical connection between the conductive member 108 and the wire 22 due to insulation breakdown.

[0071] As a countermeasure, the electrode catheter 10 may include an insulator 110 disposed between the wire 22 and the conductive member 108 in at least a certain axial range of the electrode 24. This allows the insulator 110 to block current flow between the wire 22 and the conductive member 108 even if the insulating layer 42 becomes thin at the location where the electrode 24 presses the wire 22 against the core material 20. This in turn prevents unintended conduction between the conductive member 108 and the wire 22 due to dielectric breakdown.

[0072] An insulator 110 may be disposed in a common axial range spanning multiple electrodes 24, or individual insulators 110 may be disposed in a certain axial range of each electrode 24. Also, it is sufficient that the insulator 110 is disposed in a certain axial range of at least one electrode 24, and it is not necessary that the insulator 110 be disposed in a certain axial range of each of all electrodes 24. In this embodiment, the insulator 110 is disposed in a common axial range of all electrodes 24.

[0073] The insulator 110 is made of a material having electrical insulation properties. The material of the insulator 110 is not particularly limited, and may be made of a synthetic resin such as polyimide. The insulator 110 may be provided so as to surround the center line C20 of the core material 20. The specific shape of the insulator 110 is not particularly limited. For example, the insulator 110 may be made of a cylindrical member as in this embodiment, or may be made of a coil-shaped member. When made of these materials, the cross-sectional shape perpendicular to the axial direction of the insulator 110 is not particularly limited.

[0074] Here, an example has been described in which the elastic member 26 serves as the conductive member 108. However, the core material 20 may serve as the conductive member 108. In this case, the elastic member 26 disposed between the core material 20 serving as the conductive member 108 and the wire body 22 may also serve as the insulator 110. That is, the elastic member 26 may also serve as the insulator 110, or the insulator 110 may be provided separately from the elastic member 26. Furthermore, the core material 20 and the elastic member 26 may each serve as individual conductive members 108. In this case, when the core material 20, the wire body 22, and the elastic member 26 are disposed in this order radially outward, one insulator 110 may be disposed between the core material 20 serving as one conductive member 108 and the wire body 22, and another insulator 110 may be disposed between the elastic member 26 serving as the other conductive member 108 and the wire body 22.

[0075] (Third embodiment) See Figure 14. The electrode catheter 10 of this embodiment includes a covering member 122 that covers at least a portion of the rod-shaped member 14, from the radially outer side, that is continuous with the end surface 14a at the axial end of the rod-shaped member 14. The covering member 122 of this embodiment is provided around the end surface 14a on the distal side, but may also be provided around the end surface 14a on the proximal side. The covering member 122 may also be provided so as to surround the center line C14 of the rod-shaped member 14. To achieve this, the covering member 122 of this embodiment is made of a tubular member. Specific examples of the covering member 122 for achieving this are not limited to this, and the covering member 122 may also be made of an adhesive or the like.

[0076] The covering member 122 of this embodiment is held in a state in which the rod-shaped member 14 is fastened from the radially outside at the portion covered by the covering member 122, and is thereby fixed to the rod-shaped member 14. To achieve this, the covering member 122 of this embodiment is crimped to the rod-shaped member 14 by impact such as swaging. The covering member 122 may be made of, for example, metal. The diameter of a portion of the rod-shaped member 14 is reduced by fastening the covering member 122. The specific means for fixing the covering member 122 to the rod-shaped member 14 is not limited to this, and adhesive or the like may also be used.

[0077] Burrs may occur on the end surface 14a of the rod-shaped member 14. These burrs can occur at the edge 14b between the end surface 14a and the outer periphery of the rod-shaped member 14. This can occur, for example, when obtaining the rod-shaped member 14 by extrusion molding or the like, during the process of cutting a long molded product that serves as the rod-shaped member 14. If these burrs extend radially outward from the edge 14b, they can increase insertion resistance due to contact between the end surface 14a of the rod-shaped member 14 and biological tissue, etc. In this specification, "insertion resistance" refers to, for example, insertion resistance due to contact with biological tissue, etc. when inserting the electrode catheter 10 into the body. To address this issue, the covering member 122 of this embodiment covers at least a portion of the rod-shaped member 14 that is continuous with the end surface 14a of the rod-shaped member 14 from the radially outer side. This prevents burrs from contacting biological tissue, etc., at the end surface 14a of the rod-shaped member 14, thereby suppressing an increase in insertion resistance due to the burrs.

[0078] The covering member 122 in this embodiment is provided in an axial range spanning the end surface 14a of the rod-shaped member 14 in the axial direction, and also radially covers at least a portion of the core material 20 axially outward from the end surface 14a. Here, "axially outward" refers to the side axially away from the axial center position (not shown) of the rod-shaped member 14. The opposite axial side is referred to as "axially inward." As in this embodiment, the covering member 122 may cover the base end of the outer coil 92 from the radially outward, along with a portion of the rod-shaped member 14. This results in a longer axial length of the covering member 122 axially outward from the end surface 14a of the rod-shaped member 14 compared to when the outer coil 92 is not covered. This makes it easier for the covering member 122 to prevent the end surface 14a of the rod-shaped member 14 from getting caught on biological tissue, etc., which is advantageous in reducing insertion resistance due to such catching.

[0079] As in the present embodiment, the covering member 122 may clamp the base end of the outer coil 92 from the radially outer side together with the end surface portion 14a of the rod-shaped member 14. This allows the covering member 122 to maintain a state in which the outer coil 92 is pressed against the core material 20 directly or via another member (here, the inner coil 44). As a result, the degree of fixation of the outer coil 92 to the core material 20 can be increased. As in the present embodiment, the base end of the outer coil 92 may also be fixed to the core material 20 using an adhesive 128. The adhesive 128 is filled between the covering member 122 and the core material 20 and fixes the outer coil 92 and the inner coil 44 to the core material 20 together with the covering member 122. This further increases the degree of fixation of the outer coil 92 to the core material 20.

[0080] The covering member 122 may include an outer diameter reducing portion 122a whose outer diameter decreases axially outward from the end surface 14a of the rod-shaped member 14. The outer diameter reducing portion 122a may have a curved or tapered shape, in which the outer diameter decreases continuously, or a stepped shape, in which the outer diameter decreases stepwise. In this embodiment, the outer diameter reducing portion 122a has a curved shape that continues to the outer end 122b at the axially outer end of the covering member 122. This curved outer diameter reducing portion 122a is formed by plastically deforming the covering member 122 by impact, such as swaging. This allows the outer diameter at the outer end 122b of the covering member 122 to be smaller than the outer diameter at the inner end 122c at the axially inner end, compared to a covering member 122 not including the outer diameter reducing portion 122a. Therefore, compared to this case, this is advantageous in reducing the insertion resistance caused by contact of the outer end 122b of the covering member 122 with biological tissue or the like.

[0081] 14, the possible position of the wire body 22 in a cross section along the axial direction is schematically shown by a two-dot chain line. An insulator 130 may be disposed between the outer coil 92 and the wire body 22. The insulator 130 serves to prevent current from flowing between the outer coil 92 and the wire body 22. The insulator 130 may be disposed closer to the tip of the rod-shaped member 14, as in this embodiment.

[0082] When an adhesive or the like is used, the covering member 122 may cover a portion of the rod-shaped member 14 that is continuous with the end surface portion 14a from the radial outside, while also covering the end surface portion 14a from the axial direction.

[0083] Next, variations of the components described above will be described.

[0084] The electrode catheter 10 may include an electrode assembly provided distally of the catheter shaft 30. The electrode assembly may be configured with a plurality of bendable splines. The rod-shaped member 14 may constitute each of the plurality of splines.

[0085] The elastic member 26 does not have to be disposed between the rod-shaped member 14 and the core material 20. To satisfy the condition that the rod-shaped member 14 "presses the elastic member 26 and the electric wire 22 toward the core material 20," the elastic member 26 does not have to include the inner coil 44. To satisfy this condition, the elastic member 26 may include, for example, rubber. When the elastic member 26 includes the inner coil 44, the rod-shaped member 14 does not have to be held by the electrode 24 in a state in which the elastic member 26 and the electric wire 22 are pressed toward the core material 20.

[0086] To satisfy the condition that the rod-shaped member 14 is held in a state in which the elastic member 26 and the wire body 22 are pressed against the core material 20 by the rod-shaped member 14, it is not necessary to embed the electrode 24 in the rod-shaped member 14. For example, the rod-shaped member 14 may be made of an easily deformable material, and the rod-shaped member 14 may be deformed in accordance with the reduction in diameter of the electrode 24 without causing plastic flow of the rod-shaped member 14, thereby satisfying the above-mentioned condition.

[0087] The core material 20 does not necessarily have to include the tapered portion 50. In this case, the core material 20 may include only the straight portion 52.

[0088] The elastic member 26 may be provided in an axial range that includes at least one electrode 24 and at least one fixing member 28. The fixing member 28 does not have to be fixed to the outer periphery of the rod-shaped member 14.

[0089] The outer coil 92 and the inner coil 44 do not necessarily have to be provided between the tip member 90 and the rod-shaped member 14. In this case, the tip member 90 may be attached to the tip of the rod-shaped member 14. Also, it is sufficient that at least one of the outer coil 92 and the inner coil 44 is provided between the tip member 90 and the rod-shaped member 14. The inner coil 44 that satisfies this condition does not necessarily have to be pressed against the core material 20 by the rod-shaped member 14.

[0090] The inner coil 44 may be provided only on the distal side of the proximal end 92a of the outer coil 92, without extending further proximally than the proximal end 92a. The winding directions of the outer coil 92 and the inner coil 44 may be the same.

[0091] The above-described embodiments and variations are merely examples. The abstract technical concepts should not be construed as being limited to the content of the embodiments and variations. Many design modifications, such as changes, additions, and deletions of components, are possible in the contents of the embodiments and variations. In the above-described embodiments, the terms "this embodiment" and "embodiment" are used to emphasize the content that allows such design modifications. However, design modifications are also permitted even in content without such notation. Hatching on cross sections in the drawings does not limit the material of the hatched object. The structures and numerical values ​​referred to in the embodiments and variations naturally include those that can be considered identical when taking into account manufacturing errors, dimensional errors, etc. Any combination of the above components is also valid. For example, any description of another embodiment may be combined with any embodiment, and any description of an embodiment and another variation may be combined with any description of an embodiment.

[0092] When the technical ideas embodied in the above-described embodiments and modified forms are generalized, it can be said that the technical ideas described in the following items are included.

[0093] The first item is an electrode catheter comprising: a rod-shaped member having a lumen formed therein; a core material at least a portion of which is located within the lumen; a wire body composed of a plurality of wires wound spirally around the core material, at least a portion of which is located within the lumen; and a plurality of electrodes fixed to the outer periphery of the rod-shaped member and electrically connected to the wires; wherein the region from the tip of the rod-shaped member to the base end of the electrode closest to the base end is defined as a first region, and the region from the base end of the electrode closest to the base end of the rod-shaped member is defined as a second region, and the average outer diameter of the core material in the first region is smaller than the average outer diameter of the core material in the second region.

[0094] The problem to be solved by the disclosures in the above items is to improve the trackability of the electrode catheter.

[0095] The present disclosure relates to electrode catheters.

[0096] 10...electrode catheter, 12...lumen, 14...rod-shaped member, 20...core member, 22...wire body, 24...electrode, 26...elastic member, 28...fixing member, 30...catheter shaft, 38...wire, 44...inner coil, 50...tapered portion, 60...gap, 90...tip member, 92...outer coil

Claims

1. An electrode catheter comprising: a rod-shaped member having a lumen formed therein; a core member at least a portion of which is located within said lumen; an electric wire body formed of a plurality of electric wires wound helically around said core member and at least a portion of which is located within said lumen; and a plurality of electrodes fixed to the outer periphery of said rod-shaped member and electrically connected to said electric wires, wherein said core member and said electric wire body are spaced apart within at least a portion of the axial range of said rod-shaped member.

2. An electrode catheter comprising: a rod-shaped member having a lumen; a core material at least a portion of which is located within the lumen; an electric wire body composed of a plurality of electric wires wound spirally around the core material and at least a portion of which is located within the lumen; and a plurality of electrodes fixed to the outer periphery of the rod-shaped member and electrically connected to the electric wires, wherein when the region from the tip of the rod-shaped member to the base end of the electrode closest to the base end is defined as a first region, and the region from the base end of the electrode closest to the base end to the rod-shaped member is defined as a second region, the average outer diameter of the core material in the first region is smaller than the average outer diameter of the core material in the second region.

3. An electrode catheter as described in claim 1 or 2, which is provided with an elastic member disposed between the rod-shaped member and the core material, and the rod-shaped member is held by the electrode in a state in which at least the elastic member and the electric wire body are pressed against the core material within a certain axial range of the electrode.

4. An electrode catheter according to claim 3, wherein the electrode is fixed to the rod-shaped member by being at least partially embedded in the outer periphery of the rod-shaped member.

5. An electrode catheter according to claim 3 or 4, wherein at least one of the elastic member and the core member is a conductive member, and an insulator is provided between the electric wire and the conductive member at least in a certain axial range of the electrode.

6. An electrode catheter according to any one of claims 1 to 5, wherein the core member has a tapered portion that gradually becomes thinner toward the tip, and the tapered portion is provided within a certain axial range of at least one of the electrodes.

7. An electrode catheter as described in claim 6, further comprising an elastic member disposed between the rod-shaped member and the core material, wherein the rod-shaped member is held by the electrode in a state in which at least the elastic member and the electric wire are pressed against the core material within the axial range in which the electrode is located.

8. An electrode catheter according to any one of claims 1 to 7, further comprising an elastic member disposed between the rod-shaped member and the core member, the elastic member comprising an inner coil wound helically around the core member.

9. An electrode catheter as described in claim 8, wherein the rod-shaped member is held by the electrode in a state where at least the elastic member and the electric wire body are pressed against the core material within a certain axial range of the electrode.

10. An electrode catheter according to claim 8 or 9, wherein the helical pitch of said wire body is greater than the helical pitch of said inner coil.

11. An electrode catheter according to any one of claims 1 to 10, wherein the rod-shaped member is a catheter shaft, and the core member has a tapered portion that gradually becomes thinner toward the tip.

12. An electrode catheter as described in any one of claims 1 to 11, wherein the core material extends distally beyond the tip of the rod-shaped member, and comprises: a tip member attached to the tip of the core material distally beyond the tip of the rod-shaped member; and a coil wound spirally around the core material, at least a portion of which is provided between the tip member and the rod-shaped member.

13. The electrode catheter of claim 12, wherein said coil comprises an inner coil located at least partially within said lumen.

14. The electrode catheter of claim 12, wherein the coil comprises an inner coil and an outer coil surrounding the inner coil.

15. The electrode catheter of claim 14, wherein said inner coil extends proximally beyond the proximal end of said outer coil.

16. An electrode catheter according to claim 14 or 15, wherein the winding direction of the outer coil is opposite to the winding direction of the inner coil.

17. An electrode catheter as described in any one of claims 1 to 16, further comprising a fixing member fixed to the outer periphery of the rod-shaped member on the base end side of the plurality of electrodes, wherein the rod-shaped member is held by the fixing member in a state in which at least the wire body is pressed against the core material within a certain axial range of the fixing member.

18. An electrode catheter according to claim 17, further comprising an elastic member disposed between the rod-shaped member and the core material, the elastic member being provided in a certain axial range of at least one of the electrodes and not being provided in a certain axial range of at least one of the fixing members.

19. An electrode catheter according to any one of claims 1 to 18, comprising a covering member that covers from the radially outer side at least a portion of the rod-shaped member that is continuous with the end face portion of the rod-shaped member.

20. An electrode catheter according to claim 19, further comprising a coil at least a portion of which is provided on the distal side of said rod-shaped member, and said covering member covers said coil together with a portion of said rod-shaped member from the radially outer side.

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