Electrode catheter

Abstract

This electrode catheter comprises: a rod-form member 12; an electrode 14 fixed to the outer peripheral part of the rod-form member 12; and an electric wire 16 electrically connected to the electrode 14. The electric wire 16 is provided with: a conductive wire 32 having a joining part 30 joined to the electrode 14; and an insulator 34 covering the conductive wire 32. The conductive wire 32 is provided with a reverse surface 36 facing the electrode 14 in a cross-section that passes through the joining part 30 and is orthogonal to the conductive wire axial direction. At least part of the conductive wire 32 other than the reverse surface 36, in the aforementioned cross-section, is covered by the insulator 34.

Description

Electrode catheter

[0001] The present disclosure relates to electrode catheters.

[0002] Patent Document 1 discloses an electrode catheter including a catheter shaft, an electrode fixed to the outer periphery of the catheter shaft, and an electric wire electrically connected to the electrode. The electric wire includes a conductor having a coupling portion coupled to the electrode, and an insulator covering the conductor.

[0003] Japanese Patent Application Laid-Open No. 2017-148472

[0004] A conductor is usually not covered with an insulator over the entire circumference in a cross section passing through the joint and perpendicular to the axial direction of the conductor. Therefore, there is a risk of electromagnetic noise entering the conductor from the uncovered portion in the cross section. The inventors of the present application have recognized that there is room for improvement in the prior art in order to improve the noise resistance of electric wires.

[0005] One object of the present disclosure is to provide an electrode catheter that can improve noise resistance related to the electric wire.

[0006] An electrode catheter according to one aspect of the present disclosure comprises a rod-shaped member, an electrode fixed to the outer periphery of the rod-shaped member, and an electric wire electrically connected to the electrode, the electric wire comprising a conductor having a connecting portion that is connected to the electrode, and an insulator that covers the conductor, the conductor having a back surface facing the electrode in a cross section passing through the connecting portion and perpendicular to the axial direction of the conductor, and at least a portion of the conductor other than the back surface in the cross section is covered by the insulator.

[0007] According to the present disclosure, it is possible to improve noise resistance related to the electric wire of the electrode catheter.

[0008] Fig. 2 is a plan view showing an electrode catheter of an embodiment. Fig. 3 is a cross-sectional view schematically showing a part of the electrode catheter of an embodiment. Fig. 4 is a cross-sectional view taken along III-III in Fig. 2. Fig. 5 is a cross-sectional view taken along V-V in Fig. 2.

[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] 1 and 2, the electrode catheter 10 is inserted into the body for treatment or examination of a living body. Examination here refers to, for example, electrocardiography. Treatment here refers to, for example, ablation (Pulsed Field Ablation (PFA), radiofrequency ablation, etc.), defibrillation, etc.

[0011] The electrode catheter 10 comprises a rod-shaped member 12, an electrode 14 fixed to the outer periphery of the rod-shaped member 12, an electric wire 16 electrically connected to the electrode 14, and a handle 18 to be held by the surgeon.

[0012] The rod-shaped member 12 is inserted into the body and has flexibility that allows it to bend and deform. A lumen 20 extending in the axial direction of the rod-shaped member 12 is formed inside the rod-shaped member 12. The rod-shaped member 12 in this embodiment is a catheter shaft 22 that is attached to a handle 18 at its proximal end. The rod-shaped member 12 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 12 in this embodiment has a single-layer structure, but may also have a multi-layer structure.

[0013] The electrode 14 in this embodiment is made of a ring material. Specific examples of the electrode 14 are not limited to ring materials, and the electrode 14 may be made of a surface material or the like. The electrode 14 is made of a metal-based material with good electrical conductivity, such as platinum, gold, silver, aluminum, copper, or stainless steel. The metal-based material may be made of only the main metal, or may be made of an alloy containing the main metal as a main component.

[0014] The manner in which the electrode 14 is fixed to the rod-shaped member 12 is not particularly limited. For example, an adhesive or the like may be used as the fixing method. The electrode 14 in this embodiment is fixed to the outer periphery of the rod-shaped member 12 by embedding at least a portion of the electrode 14 in the outer periphery of the rod-shaped member 12. To achieve this, the electrode 14 in this embodiment is fixed to the outer periphery of the rod-shaped member 12 by reducing the diameter of the electrode 14 through plastic flow of the rod-shaped member 12, such as by swaging. By embedding the electrode 14 in the rod-shaped member 12, a protrusion 24 that protrudes radially inward is formed on the inner periphery of the rod-shaped member 12, which forms the lumen 20, due to the plastic flow of the rod-shaped member 12. The protrusion 24 is formed within a certain axial range of the electrode 14 on the rod-shaped member 12. The protrusion 24 is provided so as to be more protruding radially inward than both axial ends of the electrode 14 on the inner periphery of the rod-shaped member 12.

[0015] The electric wire 16 is passed through the lumen 20 of the rod-shaped member 12. The electric wire 16 is pulled out to the proximal end side through an opening (not shown) formed at the proximal end of the rod-shaped member 12, passes through the inside of the handle 18, and is electrically connected to a connector (not shown) provided on the handle 18.

[0016] At least one corresponding electric wire 16 is electrically connected to each electrode 14. In this embodiment, a single corresponding electric wire 16 is electrically connected to each electrode 14, but multiple corresponding electric wires 16 may also be electrically connected to each electrode 14. The number of electrodes 14 and electric wires 16 is not particularly limited.

[0017] The rod-shaped member 12 has a side hole 12a that penetrates from the inner peripheral surface of the rod-shaped member 12 that forms the lumen 20 to the outer peripheral surface of the rod-shaped member 12. The tip of the electric wire 16 in this embodiment is drawn out through the side hole 12a of the rod-shaped member 12 and is disposed between the electrode 14 and the rod-shaped member 12, with a portion of the wire being connected to the electrode 14. Alternatively, the tip of the electric wire 16 may be connected to the electrode 14 within the side hole 12a of the rod-shaped member 12.

[0018] The protrusion 24 of the rod-shaped member 12 in this embodiment includes an overlapping portion 24a that radially overlaps the tip of the electric wire 16 located between the electrode 14 and the rod-shaped member 12, and an electrode contact portion 24b that contacts the electrode 14. The tip of the electric wire 16 is disposed between the electrode 14 and the rod-shaped member 12, and the portion of the protrusion 24 including the overlapping portion 24a is provided so as to protrude radially inward from the electrode contact portion 24b. As a result, an arrangement space 26 is provided between the rod-shaped member 12 and the electrode 14 around the tip of the electric wire 16, in which the tip is disposed. The arrangement space 26 is in communication with the inside of the lumen 20 through the side hole 12a.

[0019] The multiple electrodes 14 are electrically connected to an external electrical device via electric wires 16 and a connector. The electrodes 14 are used to capture electrical signals emitted by a living body for measurements such as cardiac potential measurement. In this case, the electrical signals captured by the electrodes 14 are transmitted to an external measuring device (external electrical device) via the electric wires 16 corresponding to the electrodes 14 and used for processing for measurement by the external measuring device. In addition, the electrodes 14 may be used to output electricity for treating a living body, such as for ablation. In this case, electricity to be output from the electrodes 14 is supplied from an external power supply device (external electrical device) via the electric wires 16 corresponding to the electrodes 14.

[0020] Referring to FIG. 3 , the electric wire 16 includes a conductor 32 having a coupling portion 30 that is coupled to the electrode 14, and an insulator 34 that covers the conductor 32. To satisfy the condition that the conductor 32 is "coated," if the insulator 34 is present in a cross section perpendicular to the conductor axial direction (described below), it is sufficient for the insulator 34 to cover at least a portion of the conductor 32; it is not necessary for the insulator 34 to cover the entire conductor 32. The conductor 32 is made of an electrically conductive material. The material of the conductor 32 is not particularly limited and may be made of, for example, copper, aluminum, iron, etc. The insulator 34 is made of an electrically insulating material. The material of the insulator 34 is not particularly limited and may be made of, for example, an electrically insulating synthetic resin, etc.

[0021] The electrode 14 and the conductor 32 are bonded by either fusion bonding, solid-state bonding, or a bonding material. Fusion bonding is a method of bonding two components by melting portions of the two components to be bonded together to form a fusion bond. Fusion bonding can be achieved by, for example, resistance welding, laser welding, etc., but is not limited to these. Solid-state bonding is a method of bonding two components by metallic bonding between the metal atoms that make up the two components without melting them. Solid-state bonding can be achieved by, for example, friction welding, gas pressure welding, explosive welding, etc., but is not limited to these. Bonding using a bonding material includes brazing using a brazing material as the bonding material and adhesion using a conductive adhesive as the bonding material. Fusion bonding, solid-state bonding, and brazing are types of material bonding, while adhesion is a type of chemical bonding. The electrode 14 and the conductor 32 can also be said to be bonded by material bonding or chemical bonding. In either case, a bonding portion 30 that connects the electrode 14 and the conductor 32 is provided between the electrode 14 and the conductor 32. The joint 30 of the conductor 32 refers only to the portion of the electrode 14 that is joined by either fusion bonding, solid-state bonding, or a bonding material, and does not include any other portion. In this embodiment, an example in which fusion bonding is used will be described. The details of this joint 30 will be described later.

[0022] In a cross section passing through the joint portion 30 and perpendicular to the conductor axial direction (hereinafter referred to as an axially orthogonal cross section), the conductor 32 comprises a back surface 36 facing the electrode 14, a front surface 38 on the opposite side of the center line C32 of the conductor 32 from the back surface 36, and a pair of side surfaces 40 connecting the front surface 38 and the back surface 36. Here, the "conductor axial direction" refers to the direction along the center line C32 of the conductor 32. The center line C32 here refers to a line extending from one end of the conductor 32 to the other end and passing through the center of the conductor 32. The center of the conductor 32 coincides with the geometric center of gravity of the outline of the conductor 32 in the cross section perpendicular to the center line C32. In addition, in an orthogonal cross section passing through the joint 30 of the conductor 32, the direction perpendicular to the line segment L1 connecting both ends 43 of the interface between the electrode 14 and the conductor 32 in the circumferential direction of the conductor is referred to as the front-back direction X, and the direction perpendicular to the front-back direction X (the direction along the line segment L1) is referred to as the lateral direction Y. The front surface 38 of the conductor 32 is on the opposite side of the center line C32 from the back surface 36 in the front-back direction X. Here, the "conductor circumferential direction" refers to the circumferential direction of a circle centered on the center line C32 of the conductor 32. The electrode 14 has a wire-facing surface 42 that faces the back surface 36 of the conductor 32. In this embodiment, the wire-facing surface 42 is the inner circumferential surface of the electrode 14.

[0023] When fusion welding is used, the joint 30 connecting the electrode 14 and the conductor 32 is formed as a fusion joint formed by melting a portion of the electrode 14 and the conductor 32. In this case, the joint 30 is provided at a midpoint in the circumferential direction of the back surface 36 of the conductor 32, and the back surface 36 of the conductor 32 directly contacts the wire-facing surface 42 of the electrode 14. In this embodiment, an example is shown in which the electrode 14 and the conductor 32 are joined by fusion welding, and the position of the joint 30 is indicated by a dashed line. When solid-state welding is used, the joint 30 is formed by the back surface 36 of the conductor 32 and at least a portion of the wire-facing surface 42 of the electrode 14. In this case, the back surface 36 of the conductor 32 directly contacts the wire-facing surface 42 of the electrode 14. When a bonding material is used, the joint 30 is formed by the bonding material disposed between the back surface 36 of the conductor 32 and the wire-facing surface 42 of the electrode 14. In this case, the back surface 36 of the conductor 32 is indirectly in contact with the conductor-facing surface 42 of the electrode 14 via the binder. In either case, the back surface 36 of the conductor 32 is in direct or indirect contact with the conductor-facing surface 42 of the electrode 14.

[0024] The back surface 36 of the conductor 32 in this embodiment has a shape similar to the conductor-facing surface 42 of the electrode 14 that it faces. The back surface 36 of the conductor 32 is continuous with each of the pair of side surfaces 40 via back-side corners 44 formed between the back surface 36 and each of the pair of side surfaces 40. The front surface 38 of the conductor 32 is continuous with each of the pair of side surfaces 40 via front-side corners 46 formed between the back surface 36 and each of the pair of side surfaces 40. Each of the pair of side surfaces 40 is provided individually on both sides of the conductor 32 in the horizontal direction Y.

[0025] In a cross section orthogonal to the axis passing through the coupling portion 30, at least a portion of the conductor 32 other than the back surface 36 is covered with the insulator 34. Here, "at least a portion other than the back surface 36" refers to the front surface 38 of the conductor 32 and at least a portion of the opposing side surface 40. In this embodiment, each of the opposing side surfaces 40 of the conductor 32 is covered with the insulator 34. When covering the side surfaces 40 of the conductor 32, it is sufficient that at least a portion of the side surface 40 is covered, and either the entire side surface 40 or only a portion of the side surface 40 may be covered. Alternatively, only the front surface 38 of the conductor 32 may be covered with the insulator 34.

[0026] In this embodiment, the surface 38 of the conductor 32 is exposed from the insulator 34. This means that the surface 38 of the conductor 32 is not covered by the insulator 34. To satisfy the condition that the surface 38 of the conductor 32 is exposed from the insulator 34, it is sufficient that at least a portion of the surface 38 is exposed from the insulator 34. In other words, it is sufficient that either the entire surface 38 of the conductor 32 or only a portion of the surface 38 is exposed from the insulator 34. In this embodiment, the entire surface 38 is exposed from the insulator 34.

[0027] The insulator 34 includes a side covering portion 50 that covers the side surface 40 of the conductive wire 32, and protrusions 56A, 56B that protrude laterally from at least one of the electrode-side end 52 and the counter-electrode-side end 54 of the side covering portion 50. Here, "side" refers to a direction away from the referenced end 52, 54 in the transverse direction Y relative to the conductive wire 32. The electrode-side end 52 refers to the end of the side covering portion 50 on the electrode 14 side. The counter-electrode-side end 54 refers to the end of the side covering portion 50 opposite the electrode 14. The electrode-side end 52 is the end of the side covering portion 50 on the back surface 36 side of the conductive wire 32 in the front-back direction X, and the counter-electrode-side end 54 is also the end of the side covering portion 50 on the front surface 38 side in the front-back direction X. The side covering portion 50 and the protrusions 56A, 56B each have a film-like shape in an axial cross section passing through the coupling portion 30.

[0028] The side surface covering portions 50 of this embodiment are individually provided corresponding to the respective pair of side surfaces 40. The side surface covering portions 50 are in close contact with the side surfaces 40 of the conducting wires 32 at the portions that they cover.

[0029] The protrusions 56A, 56B include an electrode-side protrusion 56A protruding from the electrode-side end 52 of the side covering portion 50 and a counter-electrode-side protrusion 56B protruding from the counter-electrode-side end 54 of the side covering portion 50. The electrode-side protrusion 56A is in contact with the conductor-facing surface 42 of the electrode 14. The counter-electrode-side protrusion 56B is in contact with the outer surface of the rod-shaped member 12 (here, the outer circumferential surface of the rod-shaped member 12).

[0030] The maximum thickness t1 (mm) of the protrusions 56A and 56B is thicker than the maximum thickness t2 (mm) of the side covering portion 50. In other words, t1 > t2. The thickness of the side covering portion 50 here refers to the thickness in the radial direction (hereinafter referred to as the conductor radial direction) of the conductor 32, with the center line C32 of the conductor 32 as the circle center, in an axis-orthogonal cross section passing through the joint 30. The maximum thickness of the side covering portion 50 refers to the maximum thickness within the thickness distribution of one side covering portion 50 in the conductor circumferential direction. The thickness of the protrusions 56A and 56B refers to the thickness in the normal direction of the outer surface of the other member with which the protrusions 56A and 56B are in contact, in an axis-orthogonal cross section passing through the joint 30. Here, the other member refers to the electrode 14 in the case of the electrode-side protrusion 56A, and the rod-shaped member 12 in the case of the counter-electrode-side protrusion 56B. The maximum film thickness of the protruding portions 56A, 56B refers to the maximum film thickness in the film thickness distribution of one of the protruding portions 56A, 56B in the horizontal direction Y. The relationship t1 > t2 only needs to be satisfied by the relationship between the maximum film thickness t2 of one of the side surface covering portions 50 and the maximum film thickness t1 of either of the two protruding portions 56A, 56B protruding from that one of the side surface covering portions 50. In this embodiment, this relationship is satisfied by the relationship between the maximum film thickness t2 of one of the side surface covering portions 50 and the maximum film thickness t1 of each of the two protruding portions 56A, 56B protruding from that one of the side surface covering portions 50.

[0031] The electric wire 16 satisfying the above conditions may be obtained, for example, by manufacturing the electric wire 16 satisfying the above conditions in advance, prior to joining the electric wire 16 to the electrode 14. Alternatively, the electric wire 16 satisfying the above conditions may be obtained in the process of joining the electric wire 16 to the electrode 14 using a method that is currently or will be available in the future. In any case, the method for obtaining the electric wire 16 satisfying the above conditions is not particularly limited.

[0032] The effects of the electrode catheter 10 described above will be explained. In an axially orthogonal cross section passing through the joint 30 of the conductor 32, at least a portion of the conductor 32, except for the back surface 36, is covered with the insulator 34. Therefore, in an axially orthogonal cross section passing through the joint 30 of the conductor 32, the insulator 34 can block electromagnetic noise. Therefore, in that axially orthogonal cross section, the insulator 34 can suppress the intrusion of electromagnetic noise into the conductor 32 at the covered portion, which is advantageous for improving the noise resistance of the electric wire 16.

[0033] Furthermore, in a cross section perpendicular to the axis passing through the joint 30 of the conductor 32, contact of corrosive substances that cause corrosion with the conductor 32 can be suppressed at the portion covered by the insulator 34, which is advantageous for improving corrosion resistance. Here, the corrosive substance refers to, for example, body fluids, oxygen, etc. This corrosive substance can come into contact with the conductor 32 if it is present around the joint 30 of the electric wire 16 for some reason. Here, an example of such a reason is when a corrosive substance flows from the lumen 20 of the rod-shaped member 12 into the space around the joint 30 of the electric wire 16 (e.g., the arrangement space 26).

[0034] The insulator 34 covers the side surface 40 of the conductor 32. This prevents electromagnetic noise from penetrating the side surface 40 of the conductor 32 at the covered portion of the insulator 34, which is advantageous for improving noise resistance of the electric wire. It also prevents corrosive substances from coming into contact with the side surface 40 of the conductor 32, which is advantageous for improving corrosion resistance.

[0035] The surface 38 of the conductor 32 is exposed from the insulator 34. The advantages of this are explained below. See FIG. 4 . When joining the electrode 14 and the conductor 32, a pressure member 60 may be used to press the electrode 14 and the conductor 32 toward each other in the front-to-back direction X during the joining process. For example, this is the case when joining the electrode 14 and the conductor 32 by resistance welding or solid-state welding. In this case, the electrode 14 and the conductor 32 are placed between a pair of pressure members 60, and then the pair of pressure members press them in the direction D1. In the case of resistance welding, for example, the pressure members 60 function as electrodes. When the surface 38 of the conductor 32 is exposed from the insulator 34, the pressure member 60 pressed against the surface 38 can directly apply pressure to the conductor 32. This makes it difficult for the pressure applied by the pressure member 60 to be dispersed into the insulator 34, thereby increasing the surface pressure acting on the back surface 36 of the conductor 32. Increasing the surface pressure in this manner is advantageous for increasing the bonding strength during the joining process between the electrode 14 and the conductor 32.

[0036] The insulator 34 has protrusions 56A, 56B that protrude laterally from the side covering portion 50. By bringing the protrusions 56A, 56B into contact with other members, it is possible to prevent corrosive substances from entering between the protrusions 56A, 56B and other members, which is advantageous in preventing corrosive substances from coming into contact with the conductor 32.

[0037] The electrode-side protrusion 56A of the insulator 34 contacts the electrode 14. This prevents corrosive substances from entering between the electrode-side protrusion 56A of the insulator 34 and the electrode 14, which is advantageous in preventing corrosive substances from coming into contact with the area around the back surface 36 of the conducting wire 32.

[0038] The counter-electrode side protrusion 56B of the insulator 34 contacts the rod-shaped member 12. This prevents corrosive substances from entering between the counter-electrode side end 54 of the insulator 34 and the rod-shaped member 12, which is advantageous in preventing corrosive substances from coming into contact with the surface 38 of the conductor 32.

[0039] The maximum film thickness t1 of the protrusions 56A, 56B of the insulator 34 is greater than the maximum film thickness t2 of the side surface covering portion 50. This makes the protrusions 56A, 56B of the insulator 34 less likely to deform than when this condition is not met, making it easier for the protrusions 56A, 56B to maintain contact with other members. This in turn advantageously prevents corrosive substances from penetrating between the protrusions 56A, 56B of the insulator 34 and other members.

[0040] Next, other features of the electrode catheter 10 will be described. Referring to Figure 2, the wire 16 includes an electrode bonding region 70 and a covering region 72, which constitute separate portions of the wire 16 along its axial direction. In the electrode bonding region 70, the wire 32 is bonded to the electrode 14, and as described above, the wire 32 is partially covered with the insulation 34. The electrode bonding region 70 is provided within the axial range of the wire 32 where the bonding portion 30 is located.

[0041] Referring to Figure 5, in the coated region 72, the conductor 32 is not bonded to the electrode 14, and the entire periphery of the conductor 32 is coated with the insulator 34. The coated region 72 is located closer to the base end than the electrode bonding region 70. The maximum thickness t3 (mm) of the insulator 34 in the coated region 72 will be considered. The thickness of the insulator 34 in this coated region 72 refers to the thickness in the radial direction of the conductor in a cross section perpendicular to the axis passing through the coated region 72. This maximum thickness t3 refers to the maximum thickness within the distribution of the insulator 34 thickness in the circumferential direction of the conductor in the coated region 72.

[0042] Referring to FIG. 3 , consider an orthogonal cross section passing through the joint 30 of the conductor 32. In this cross section, a line segment L2 parallel to the horizontal direction Y, starting from the side surface 40 on one side of the conductor 32 in the horizontal direction Y and ending at the tip of one of the protrusions 56A, 56B on that side of the conductor 32 in the horizontal direction Y, has a maximum length L56. The starting and ending ends of the line segment L2 are on the same side of the conductor 32 in the horizontal direction Y. Here, the tip of the protrusions 56A, 56B refers to the outer end of the protrusions 56A, 56B in the horizontal direction Y. Depending on the shape of the protrusions 56A, 56B, the position of the tip of the protrusions 56A, 56B may be determined at a single location, and the length of the line segment L2 ending at that tip may also be uniquely determined. For example, as in the present embodiment, the outer end faces of the protrusions 56A, 56B in the left-right direction Y are inclined with respect to the front-back direction X. However, depending on the shape of the protrusions 56A, 56B, the positions of the tips of the protrusions 56A, 56B may not be fixed at a single location, and the length of the line segment L2 that terminates at the tips may not be uniquely determined. For example, this may be the case when the outer end faces of the protrusions 56A, 56B in the left-right direction Y are parallel to the front-back direction X. In such a case, when considering the maximum lateral length L56, the line segment L2 with the longest length is defined as the maximum lateral length L56, as described above. Here, the maximum lateral length L56 corresponding to the electrode-side protrusion 56A is illustrated.

[0043] In this case, the maximum lateral length L56 corresponding to the protrusions 56A, 56B is greater than the maximum film thickness t3 of the insulator 34 in the covered region 72. When the insulator 34 includes multiple protrusions 56A, 56B, it is sufficient that the maximum lateral length L56 corresponding to at least one of the protrusions 56A, 56B is greater than the maximum film thickness t3. In this embodiment, the maximum lateral length L56 corresponding to each of the protrusions 56A, 56B is greater than the maximum film thickness t3.

[0044] As a result, by increasing the maximum lateral length L56 corresponding to the protrusions 56A, 56B, it becomes easier to widen the contact area of ​​the protrusions 56A, 56B with other components, compared to when this condition is not met. This in turn can advantageously prevent corrosive substances from penetrating between the protrusions 56A, 56B of the insulator 34 and other components. This effect is more effectively achieved as the maximum lateral length L56 is increased. From this perspective, the maximum lateral length L56 may be, for example, two or more times the maximum film thickness t3.

[0045] The maximum film thickness t1 of the protrusions 56A, 56B is greater than the maximum film thickness t3 of the insulator 34 in the covered region 72. When the insulator 34 includes multiple protrusions 56A, 56B, it is sufficient that the maximum film thickness t1 of at least one of the protrusions 56A, 56B is greater than the maximum film thickness t3. In this embodiment, the maximum film thickness t1 of each of the protrusions 56A, 56B of the insulator 34 is greater than the maximum film thickness t3.

[0046] This makes it more difficult for the protrusions 56A, 56B of the insulator 34 to deform, making it easier for the protrusions 56A, 56B to maintain contact with other members, compared to when this condition is not met, and ultimately makes it possible to advantageously prevent corrosive substances from entering between the protrusions 56A, 56B of the insulator 34 and other members.

[0047] Next, variations of the components described above will be described.

[0048] The electrode catheter 10 may include an electrode assembly provided distally of the catheter shaft 22. The electrode assembly may be configured with a plurality of bendable splines. The rod-shaped member 12 may constitute each of the plurality of splines.

[0049] The insulator 34 may include only the side covering portion 50 and may not include the protrusions 56A, 56B. The protrusions 56A, 56B of the insulator 34 may include at least one of the electrode-side protrusion 56A and the counter-electrode-side protrusion 56B. For example, the protrusions 56A, 56B may include only the electrode-side protrusion 56A or only the counter-electrode-side protrusion 56B.

[0050] The relationship in magnitude between the maximum film thickness t1 of the protrusions 56A, 56B and the maximum film thickness t2 of the side surface covering portion 50 is not particularly limited. For example, the relationship may be maximum film thickness t1≦maximum film thickness t2. Furthermore, the relationship in magnitude between the maximum film thickness t1 of the protrusions 56A, 56B and the maximum film thickness t3 of the insulator 34 in the covering region 72 is not particularly limited. For example, the relationship may be maximum film thickness t1≦maximum film thickness t3.

[0051] The above-described embodiments and variations are merely examples. The abstract technical ideas should not be interpreted as being limited to the contents of the embodiments and variations. Many design changes are possible in the contents of the embodiments and variations, such as changing, adding, or deleting components. In the above-described embodiments, the contents that allow such design changes are emphasized by adding the notation "this embodiment" or "embodiment." However, design changes are also permitted even in contents without such notation. Hatching on cross sections in the drawings does not limit the material of the hatched objects.

[0052] The present disclosure relates to electrode catheters.

[0053] 10...electrode catheter, 12...rod-shaped member, 14...electrode, 16...electric wire, 30...connection portion, 32...conductor, 34...insulator, 36...back surface, 38...surface, 40...side surface, 50...side surface covering portion, 52...electrode side end, 54...counter-electrode side end, 56A...electrode side protrusion, 56B...counter-electrode side protrusion, 72...covered area.

Claims

1. An electrode catheter comprising: a rod-shaped member; an electrode fixed to the outer periphery of the rod-shaped member; and an electric wire electrically connected to the electrode, wherein the electric wire comprises a conductor having a coupling portion coupled to the electrode, and an insulator covering the conductor, wherein the conductor has a back surface facing the electrode in a cross section passing through the coupling portion and perpendicular to the axial direction of the conductor, and at least a portion of the conductor other than the back surface is covered by the insulator in the cross section.

2. An electrode catheter according to claim 1, wherein the conductor has, in the cross section, a front surface on the opposite side of the center line of the conductor from the back surface, and a pair of side surfaces connecting the front surface and the back surface, and the insulator covers the side surfaces.

3. The electrode catheter of claim 2, wherein said surface is exposed from said insulator.

4. An electrode catheter as described in claim 2 or 3, wherein the insulator comprises a side covering portion that covers the side surface, and a protrusion that protrudes laterally from at least one of the electrode side end and the anti-electrode side end of the side covering portion.

5. An electrode catheter according to claim 4, wherein the protrusion includes an electrode-side protrusion that protrudes from the electrode-side end, and the electrode-side protrusion contacts the electrode.

6. An electrode catheter according to claim 4 or 5, wherein the protrusion includes a counter-electrode side protrusion that protrudes from the counter-electrode side end, and the counter-electrode side protrusion contacts the rod-shaped member.

7. An electrode catheter according to any one of claims 4 to 6, wherein the maximum thickness of the protruding portion is greater than the maximum thickness of the side covering portion.

8. An electrode catheter according to any one of claims 4 to 7, wherein the front surface is on the opposite side of the back surface across the center line in the front-to-back direction from the back surface, the electric wire comprises a covering region that forms a part of the electric wire in the axial direction of the conductor and in which the conductor wire is covered with the insulator over the entire circumference, and wherein the maximum length of a line segment parallel to the horizontal direction, which has its starting end at the side surface on one horizontal side perpendicular to the front-to-back direction with respect to the conductor wire in the cross section and its ending at the tip of the protrusion on the same horizontal side with respect to the conductor wire, is referred to as the maximum horizontal length corresponding to the protrusion, and the maximum horizontal length corresponding to the protrusion is greater than the maximum film thickness of the insulator in the covering region.

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