JP7701855B2 - Electrode catheter and method for manufacturing the same - Google Patents

Description

The present invention relates to an electrode catheter used for measuring electrical potentials of internal organs, primarily the heart, and for cauterizing internal tissue, and to a method for manufacturing the electrode catheter.

Electrode catheters are primarily used as medical devices to diagnose arrhythmias by measuring cardiac potentials and to cauterize internal tissues by passing high-frequency currents to treat arrhythmias. In general, electrode catheters have multiple ring-shaped electrodes arranged on the outside of a hollow cylindrical body (shaft). Conductors connected to the inside of the ring-shaped electrodes extend from a conductor hole provided in the shaft through the hollow of the shaft to an electrocardiograph. A connector is used to connect the conductors to the electrocardiograph. For example, by inserting the electrode catheter into a patient's heart and connecting the connector to the electrocardiograph, it is possible to measure the electrocardiogram near the ring-shaped electrodes and accurately grasp the condition of the myocardium that is causing the arrhythmia.

If blood or other liquids get into the gap between the electrode and shaft and flow into the lumen of the shaft through the conductor hole, it can cause short circuits between the multiple conductors and corrosion of the conductors and the internal structure of the electrode catheter, leading to failure of the electrode catheter. In addition, if liquid gets into the lumen of the shaft, the baseline potential of the electrocardiogram measured by the electrode catheter becomes unstable, a so-called drift phenomenon occurs, making it difficult to perform accurate potential measurements and cauterization. In order to prevent failure of the electrode catheter and to perform accurate potential measurements and cauterization with the electrode catheter, it is necessary to prevent liquids from entering the lumen of the shaft.

For example, Patent Document 1 describes an electrode catheter that is difficult for liquid to penetrate into the inner cavity of the shaft, which comprises a catheter body, a control handle, a catheter tip, multiple ring electrodes, and multiple lead wires, and in which a side hole is formed in the tubular wall of the catheter tip from the outer surface to the lumen corresponding to the fixed position of the ring electrode, and each of the multiple lead wires is connected to the ring electrode by being joined to the inner surface of the ring electrode at its tip, and enters the lumen of the catheter tip from the side hole and extends to the lumen of the catheter tip, the lumen of the catheter body, and the inner hole of the control handle, and an insulating resin thin film is formed at least on the surface of the metal core wire at the tip of the lead wire and on the surface of the joint with the inner surface of the ring electrode.

Patent document 2 describes a catheter that includes a resin tube and a ring-shaped electrode disposed on the outside of the resin tube, in which the outer surface of the ring-shaped electrode is located inside the outer surface of the resin tube in a portion where the ring-shaped electrode is not disposed, and a conductor wire electrically connected to an external power source is attached to the ring-shaped electrode, the conductor wire passes through a hole that penetrates the resin tube in the radial direction and is in close contact with the inner surface of the hole, and the long axis of the opening surface of the hole is oriented parallel to the length of the resin tube, for example, in an elliptical shape.

Patent document 3 describes an electrode catheter that has a cylindrical body with an opening formed on the side, a ring electrode that covers the opening of the cylindrical body from the outside, a conductive member connected to the ring electrode and blocking at least a part of the opening, and a conductor connected to the conductive member and arranged inside the cylindrical body, in which the opening area of the opening becomes smaller toward the axis of the cylindrical body and the conductive member has a cone-shaped portion that tapers toward the axis of the cylindrical body.

Patent document 4 describes a guidewire-type electrode catheter having an electrode group consisting of a tube body, a connector, and multiple electrodes, in which the tube body has an electrode group formed by connecting and fixing the tip of a lead wire to the side of the tip side, and a side hole corresponding to the fixed position of the electrode group, the lead wire extends from the side hole through the inside of the tube body to the connector, the electrode has a metal core wire part with the resin coating at the tip peeled off and welded to the electrode by resistance welding or the like, the rear end of the lead wire welded to the electrode is connected to the connector from the side hole through the inside of the tube body, and a sealant is provided on both sides of the tip and rear end of the electrode, in the gap between the electrode and the outer peripheral surface of the first tube body, and in the gap between the inside of the electrode and the lead wire at the side hole of the first tube body, and the resin coating is adhesively bonded within the sealant so that the metal core wire of the lead wire is not exposed from the sealant.

JP 2009-268696 A JP 2015-116309 A JP 2016-137019 A JP 2021-27974 A

In the electrode catheter of Patent Document 1, an insulating resin thin film is formed on the surface of the metal core wire at the tip of the lead wire and on the surface of the joint with the inner surface of the ring electrode. However, it is very difficult to form the insulating resin thin film so that no gaps are formed between the ring electrode and the lead wire and the catheter tube wall, making it difficult to improve manufacturing efficiency.

In the catheter of Patent Document 2, the ring-shaped electrode and the lead wire are attached to the resin tube by thermally expanding the resin tube, but it can be difficult to precisely adjust the expansion of the resin tube, and there is room for improvement in terms of making manufacturing easier.

In the electrode catheter of Patent Document 3, when manufacturing the electrode catheter, it can be difficult to form an opening in the cylindrical body whose opening area decreases toward the axis of the cylindrical body, or to manufacture a conductive member having a cone-shaped portion that tapers toward the axis of the cylindrical body.

In the electrode catheter of Patent Document 4, a sealant is provided on both the front and rear side surfaces of the electrode, in the gap between the electrode and the outer peripheral surface of the first tube body, and in the gap between the inside of the electrode and the lead wire in the side hole of the first tube body, but it is difficult to provide the sealant without leaving any gaps, making it very difficult to manufacture.

The present invention was made in consideration of the above circumstances, and its purpose is to provide an electrode catheter that is less likely to have gaps between the conductor and the conductor hole formed in the shaft, and that is easy to manufacture, and a method for manufacturing the electrode catheter.

The manufacturing method of the electrode catheter that can solve the above problem includes a preparation step of preparing a shaft that extends in the longitudinal direction and has an inner lumen, an electrode, and a conductor; a recess forming step of forming a bottomed recess in the tubular wall of the shaft; a hole forming step of inserting a first end of the conductor into the bottom of the recess to form a hole in the shaft that connects the inner lumen to the outside; a conductor connecting step of connecting a second end of the conductor to the electrode; and an electrode placement step of placing the electrode on the outside of the hole.

In the manufacturing method of the electrode catheter of the present invention, it is preferable that the area of the bottom of the recess is larger than the area of the hole in a cross section perpendicular to the depth direction of the hole.

In the manufacturing method of the electrode catheter of the present invention, it is preferable that after the recess forming step, the depth of the recess is longer than the shortest distance from the bottom of the recess to the inner surface of the shaft.

In the manufacturing method of the electrode catheter of the present invention, it is preferable that the length of the bottom of the recess in the longitudinal direction of the shaft is shorter than the length of the electrode in the longitudinal direction of the shaft.

In the manufacturing method of the electrode catheter of the present invention, it is preferable that the area of the bottom of the recess is larger than the cross-sectional area perpendicular to the longitudinal axis of the conductor.

In the method for manufacturing an electrode catheter of the present invention, it is preferable that after the electrode placement process, the second end of the conductor is located outside the shaft.

In the manufacturing method of the electrode catheter of the present invention, it is preferable to have a conductor bonding process in which the conductor is fixed to the hole with an adhesive after the hole forming process.

The electrode catheter that has been able to solve the above problem has a shaft that extends in the longitudinal direction and has an inner lumen, the shaft having a hole that connects the inner lumen to the outer surface, an electrode that is disposed outside the hole, and a conductor that is connected to the electrode and extends through the hole into the inner lumen of the shaft, the shaft has a bottomed recess in the tubular wall of the shaft, the hole is provided at the bottom of the recess, the bottom of the recess is circular, and the area of the bottom of the recess is smaller than the area of the inner surface of the electrode.

In the electrode catheter of the present invention, it is preferable that the area of the bottom of the recess is larger than the area of the hole in a cross section perpendicular to the depth direction of the hole.

In the electrode catheter of the present invention, it is preferable that the depth of the recess is longer than the shortest distance from the bottom of the recess to the inner surface of the shaft.

In the electrode catheter of the present invention, it is preferable that the length of the bottom of the recess in the longitudinal direction of the shaft is shorter than the length of the electrode in the longitudinal direction of the shaft.

In the electrode catheter of the present invention, it is preferable that the area of the bottom of the recess is larger than the cross-sectional area perpendicular to the longitudinal axis of the conductor.

In the electrode catheter of the present invention, it is preferable that the second end of the conductor is located outside the shaft.

In the electrode catheter of the present invention, it is preferable that the inner wall of the shaft protrudes toward the center of the longitudinal axis of the shaft at the hole in the inner cavity of the shaft.

The manufacturing method of the electrode catheter of the present invention includes a recess forming step of forming a bottomed recess in the tubular wall of the shaft, and a hole forming step of inserting the first end of the conductor into the bottom of the recess to form a hole in the shaft that connects the inner cavity to the outside, which makes it difficult for a gap to form between the conductor and the hole. Therefore, it is possible to easily manufacture an electrode catheter that is difficult for liquids such as blood to penetrate into the inner cavity of the shaft.

In addition, according to the electrode catheter of the present invention, the shaft has a bottomed recess in the tubular wall of the shaft, a hole is provided at the bottom of the recess, the bottom of the recess is circular, and the area of the bottom of the recess is smaller than the area of the inner surface of the electrode, so that a gap is unlikely to occur between the conductor and the hole. As a result, it is possible to make it difficult for liquids such as blood to enter the lumen of the shaft.

1 shows an overall view of an electrode catheter in one embodiment of the present invention. 2 illustrates a longitudinal cross-sectional view of the electrode catheter shown in FIG. 1. 4A to 4C are cross-sectional views taken along the longitudinal axis direction of a shaft during a recess forming step in one embodiment of the present invention. 4A to 4C are cross-sectional views taken along the longitudinal axis direction of a shaft during a hole forming process in one embodiment of the present invention. 5 shows a view perpendicular to the bottom of the recess of the shaft shown in FIG. 4 . 4A to 4C are cross-sectional views taken along the longitudinal axis direction of a shaft during a lead wire connecting step according to an embodiment of the present invention. 1A and 1B are cross-sectional views taken along the longitudinal axis direction of a shaft during an electrode placement step in one embodiment of the present invention.

The present invention will be described in more detail below based on the following embodiment, but the present invention is not limited to the following embodiment, and can of course be modified as appropriate within the scope of the above and below, all of which are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, reference should be made to the specification or other drawings. In addition, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to contributing to an understanding of the features of the present invention.

Figure 1 is an overall view of an electrode catheter 1 according to one embodiment of the present invention, and Figure 2 is a cross-sectional view along the longitudinal axis of the distal end of the electrode catheter 1. As shown in Figures 1 and 2, the electrode catheter 1 includes a shaft 10 that extends in the longitudinal axis direction and has an inner lumen, an electrode 20, and a conductor 30.

In the present invention, the proximal side refers to the side of the user's hand in the extending direction of the shaft 10, and the distal side refers to the opposite side of the proximal side, i.e., the side to be treated. The extending direction of the shaft 10 is also referred to as the longitudinal axis direction. The longitudinal axis direction can also be rephrased as the near-far direction. The radial direction refers to the radial direction of the shaft 10, the inward radial direction refers to the direction toward the center of the longitudinal axis of the shaft 10, and the outward radial direction refers to the direction toward the opposite side of the inward direction. Note that in Figures 1 and 2, the right side of the figure is the proximal side, and the left side of the figure is the distal side.

First, we will explain the manufacturing method of the electrode catheter 1.

The electrode catheter 1 is used, for example, to pass from its distal end through the patient's blood vessels to the heart and to examine, treat, and defibrillate cardiac arrhythmias.

The manufacturing method of the electrode catheter 1 includes a preparation step of preparing a shaft 10 extending in the longitudinal direction and having an inner cavity, an electrode 20, and a conductor 30; a recess forming step of forming a bottomed recess 11 in the tubular wall of the shaft 10; a hole forming step of inserting a first end 31 of the conductor 30 into the bottom 12 of the recess 11 to form a hole 13 in the shaft 10 that connects the inner cavity to the outside; a conductor connecting step of connecting a second end 32 of the conductor 30 to the electrode 20; and an electrode placement step of placing the electrode 20 on the outside of the hole 13.

The preparation process involves preparing a shaft 10 that extends in the longitudinal direction and has an internal cavity, an electrode 20, and a conductor 30.

The shaft 10 may be a single lumen structure having one lumen, or a multi-lumen structure having multiple lumen. If the shaft 10 has one lumen, there is no partition or the like inside the shaft that divides the lumen, so the flexibility of the shaft 10 can be increased and the insertion of the electrode catheter 1 can be improved. If the shaft 10 has multiple lumen, the multiple conductors 30, etc. placed in the lumen can be placed in different lumens, thereby preventing the conductors 30 from coming into contact with other conductors 30, etc., and preventing damage such as breakage of the conductors 30.

The shaft 10 may be made of, for example, a polyolefin resin such as polyethylene or polypropylene, a polyamide resin such as nylon, a polyester resin such as PET, an aromatic polyetherketone resin such as PEEK, a polyetherpolyamide resin, a polyurethane resin, a polyimide resin, a fluorine resin such as PTFE, PFA, or ETFE, or a synthetic resin such as polyvinyl chloride resin. The shaft 10 may have a single-layer structure or a multi-layer structure. When the shaft 10 has a multi-layer structure, for example, the intermediate layer of the resin tube constituting the shaft 10 may be a structure using a metal braid such as stainless steel, carbon steel, or nickel-titanium alloy. The material constituting the shaft 10 is preferably a polyamide resin, and more preferably a polyamide elastomer. Since the material constituting the shaft 10 is a polyamide elastomer, the outer surface of the shaft 10 has good slipperiness, and the shaft 10 has appropriate rigidity, so that the electrode catheter 1 can be easily inserted into a blood vessel.

The length of the shaft 10 in the longitudinal direction can be selected to be appropriate for treatment. For example, the length of the shaft 10 in the longitudinal direction can be 500 mm or more and 1500 mm or less.

The outer diameter of the shaft 10 is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 1 mm or more. By setting the lower limit of the outer diameter of the shaft 10 within the above range, it is possible to impart appropriate rigidity to the shaft 10, and to provide an electrode catheter 1 with high insertability into blood vessels. In addition, the outer diameter of the shaft 10 is preferably 3 mm or less, more preferably 2.8 mm or less, and even more preferably 2.5 mm or less. By setting the upper limit of the outer diameter of the shaft 10 within the above range, it is possible to prevent the outer diameter of the electrode catheter 1 from becoming too large, and to enhance minimal invasiveness.

The thickness of the shaft 10 is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. By setting the lower limit of the thickness of the shaft 10 within the above range, it is possible to increase the rigidity of the shaft 10 and to provide an electrode catheter 1 with good insertability into blood vessels. In addition, the thickness of the shaft 10 is preferably 350 μm or less, more preferably 300 μm or less, and even more preferably 250 μm or less. By setting the upper limit of the thickness of the shaft 10 within the above range, the lumen of the shaft 10 can be widened, and the electrode 20 of the electrode catheter 1 can be multipolarized.

The electrode 20 may be a ring-shaped electrode or a flat plate electrode having a rectangular or square shape, etc. When the electrode 20 is a flat plate electrode, at least one of the back surface (inner surface) and the front surface (outer surface) of the flat plate electrode may be curved so as to easily fit the curved surface of the shaft 10. In particular, the electrode 20 is preferably ring-shaped. By using the electrode 20 as a ring-shaped electrode, the area of the electrode 20 on the circumference of the shaft 10 can be increased, making it easier to bring the electrode 20 into contact with the target site, such as the inner wall of the heart.

Examples of materials constituting the electrode 20 include metal materials such as copper, gold, platinum, aluminum, iron, and alloys of these. Of these, the material constituting the electrode 20 is preferably platinum or an alloy thereof. By configuring the electrode 20 in this manner, the contrast of the electrode 20 against X-rays can be improved, and the position of the electrode 20 can be confirmed by using X-rays when the electrode catheter 1 is in use.

It is preferable that there are multiple electrodes 20. When there are multiple electrodes 20, the size of each electrode 20 may be the same or different. The different sizes of each electrode 20 refer to, for example, that the length of the electrodes 20 in the longitudinal axis direction of the shaft 10 is different.

The conductor 30 electrically connects the electrode 20 to an external device (not shown) such as a power supply for the electrode catheter 1, and is disposed in the lumen of the shaft 10. By connecting the conductor 30 to the external device for the electrode catheter 1, the electrode 20 and the external device for the electrode catheter 1 are electrically connected. In addition, although not shown, the electrode catheter 1 may have a connector on the proximal side, and the conductor 30 may be connected to the connector, and the electrode 20 may be connected to the external device by connecting the connector to the external device for the electrode catheter 1.

Although not shown, the conductor 30 has a core and a coating. The material constituting the core of the conductor 30 may be any conductive material, such as metal materials such as iron, copper, silver, stainless steel, tungsten, nickel, titanium, or alloys thereof. Of these, it is preferable that the material constituting the core of the conductor 30 is stainless steel. Since stainless steel has straightness and rigidity, by using stainless steel as the material constituting the core of the conductor 30, it is easy to pass the conductor 30 through the lumen of the shaft 10 during the manufacture of the electrode catheter 1, and the conductor 30 is less likely to break at the connection part of the electrode 20, etc.

It is preferable that the coating of the conductor 30 is present on the portions other than the ends that are connected to other objects such as the electrode 20. Specifically, for example, the coating of the second end 32 of the conductor 30 is partially removed, and this portion is welded to the electrode 20, thereby connecting the second end 32 of the conductor 30 to the electrode 20, and the coating of the first end 31 of the conductor 30 that is connected to the external device of the electrode catheter 1 or the connector of the handle 50 is partially removed, so that the conductor 30 has a coating on the portions other than the ends.

The coating of the conductor 30 may be made of an insulating material, such as polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyetherketone resins such as PEEK, polyetherpolyamide resins, polyurethane resins, polyimide resins, fluororesins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. The material constituting the coating of the conductor 30 is preferably a fluororesin, and more preferably PFA. The coating of the conductor 30 is made of a fluororesin, which can enhance the insulation of the conductor 30, improve the sliding properties against other objects such as the conductor 30 connected to the other electrode 20 in the inner cavity of the shaft 10, and prevent damage to the coating of the conductor 30 due to contact with other objects.

Figure 3 is a cross-sectional view along the longitudinal axis of the shaft 10 during the recess formation process. As shown in Figure 3, a bottomed recess 11 is formed in the tube wall of the shaft 10. By forming the recess 11 in the tube wall of the shaft 10, it becomes easier to insert the conductor 30 into the shaft 10 during the hole formation process, making it easier to form the hole 13.

The bottom 12 of the recess 11 may be flat as shown in FIG. 3, or may be curved (not shown). In particular, it is preferable that the bottom 12 of the recess 11 be flat. By having the bottom 12 be flat, it becomes easier to form the hole 13 in the bottom 12 of the recess 11 in the hole forming step that is performed after the recess forming step.

In the recess forming process, it is preferable to form multiple recesses 11 in the tubular wall of the shaft 10. By forming multiple recesses 11 in the shaft 10, an electrode catheter 1 having multiple electrodes 20 can be manufactured.

Methods for forming the recess 11 in the shaft 10 include, for example, cutting with a drill or the like, applying pressure with a rod-shaped object such as a punch, and thermal processing by pressing a heated rod-shaped object against the shaft 10. In addition to these, for example, after forming a through hole in the shaft 10, a thin film-like object may be placed over the through hole and fixed to the shaft 10 to form the recess 11 with the thin film-like object as the bottom 12. In other words, the bottom 12 of the recess 11 may be present on the outside of the shaft 10 in the tube wall of the shaft 10, although not shown, or may be present on the inner cavity side of the shaft 10 as shown in FIG. 3. Among the methods for forming the recess 11 in the shaft 10, it is preferable to form the recess 11 by cutting the outer surface of the shaft 10 using a drill or the like. By forming the recess 11 by cutting the outer surface of the shaft 10, it is easy to form multiple recesses 11 of similar depth and size, and the recess formation process is easy to perform stably.

Figure 4 is a cross-sectional view along the longitudinal axis of the shaft 10 during the hole formation process, and Figure 5 is a view perpendicular to the bottom 12 of the recess 11 of the shaft 10 during the hole formation process. As shown in Figures 4 and 5, the hole formation process involves piercing the first end 31 of the conductor 30 into the bottom 12 of the recess 11 to form a hole 13 in the shaft 10 that connects the inner cavity to the outside. The hole formation process is performed after the recess formation process.

By piercing the first end 31 of the conductor 30 into the bottom 12 of the recess 11 to form the hole 13, the size of the hole 13 becomes close to the outer diameter of the conductor 30. As a result, it is possible to manufacture an electrode catheter 1 that is less likely to have a gap between the conductor 30 and the hole 13, and is less likely to allow blood or other liquids to penetrate into the inner cavity of the shaft 10 through this gap. It is preferable that the first end 31 of the conductor 30 is the proximal end of the conductor 30.

The extension direction of the hole 13 may be perpendicular to the longitudinal axis direction as shown in FIG. 4, or may be oblique to the longitudinal axis direction, although not shown.

As shown in FIG. 5, in the hole forming process, the location where the first end 31 of the conductor 30 is pierced is preferably the center of the bottom 12 of the recess 11. The center of the bottom 12 of the recess 11 refers to a range of a circle whose center is the center point of the bottom 12 of the recess 11 and whose radius is a point that is 50% of the longest distance from the center of the bottom 12 to the end of the bottom 12. By piercing the first end 31 of the conductor 30 into the center of the bottom 12 of the recess 11, it is easier to pierce the first end 31 of the conductor 30 into the bottom 12, and a gap is less likely to occur between the conductor 30 and the hole 13.

In the hole forming process, the location where the first end 31 of the conductor 30 is pierced is preferably within a circle whose center is the center point of the bottom 12 of the recess 11 and whose radius is 50% of the longest distance from the center of the bottom 12 to the end of the bottom 12, more preferably within a circle whose radius is 30% of the longest distance from the center of the bottom 12 to the end of the bottom 12, and even more preferably within a circle whose radius is 10% of the longest distance from the center of the bottom 12 to the end of the bottom 12. By setting the location where the first end 31 of the conductor 30 is pierced within the above range, it becomes easier to pierce the first end 31 of the conductor 30 into the bottom 12 of the recess 11, and it becomes easier to form a hole 13 in the shaft 10.

After the hole formation step, it is preferable to have a step of exposing the first end 31 of the conductor 30 from the proximal end of the shaft 10. By exposing the first end 31 of the conductor 30 from the proximal end of the shaft 10, it is possible to easily attach a member to the conductor 30 for electrically connecting the electrode catheter 1 to an external device such as a power supply unit.

Figure 6 is a cross-sectional view along the longitudinal axis of the shaft 10 during the conductor connection process. As shown in Figure 6, the conductor connection process connects the second end 32 of the conductor 30 to the electrode 20. It is preferable that the second end 32 of the conductor 30 is the distal end of the conductor 30.

The conductor 30 can be connected to the electrode 20 by, for example, welding, brazing with solder, crimping, or the like. Of these, the conductor 30 is preferably connected to the electrode 20 by welding. By connecting the conductor 30 to the electrode 20 by welding, the connection strength between the conductor 30 and the electrode 20 can be increased. Although not shown, the conductor 30 and the electrode 20 may be connected with a conductive member having conductivity between them.

The connection between the conductor 30 and the electrode 20 may be coated with a resin or the like to prevent oxidation deterioration due to moisture in the air, etc. Examples of resins used for this coating include polyurethane resins and epoxy resins.

The conductor connection step may be performed before or after the hole formation step. By performing the conductor connection step before the hole formation step, it becomes easier to connect the conductor 30 to the electrode 20 by welding or the like. By performing the conductor connection step after the hole formation step, it becomes easier to handle the conductor 30 and to form the hole 13 by piercing the conductor 30 into the shaft 10.

Figure 7 is a cross-sectional view along the longitudinal axis of the shaft 10 during the electrode placement process. As shown in Figure 7, the electrode placement process places the electrode 20 on the outside of the hole 13. It is preferable to perform the electrode placement process after the conductor connection process.

The electrode 20 is preferably disposed on the outer surface of the shaft 10. By disposing the electrode 20 on the shaft 10, it is possible to measure the intracardiac potential by bringing the electrode 20 close to or in contact with the inner wall of the heart, thereby identifying an abnormal part of the heart that is causing arrhythmia, and performing defibrillation within the cardiac cavity.

As shown in Figures 1 and 2, the electrode catheter 1 may have a tip 60 at the distal end of the shaft 10. If the electrode catheter 1 has a tip 60 at the distal end of the shaft 10, it may have a tip placement step of placing the tip 60 at the distal end of the shaft 10.

Examples of the tip tip 60 include a hemispherical electrode, a lid-like member that prevents the distal end of the shaft 10 from opening, and the like. By having the tip tip 60 at the distal end of the shaft 10, it is possible to prevent liquids such as blood from entering the lumen of the shaft 10 from the distal end of the shaft 10 when the electrode catheter 1 is in use. In addition, the tip tip 60 acts as a guide for the tip of the electrode catheter 1, making it possible to improve the insertability of the electrode catheter 1.

The material constituting the tip 60 may be, for example, the material constituting the shaft 10 or the material constituting the electrode 20. It is also possible to make the tip 60 out of a conductive material such as the material constituting the electrode 20 and connect the tip 60 to the conductor 30, so that the tip 60 also functions as the electrode 20.

As shown in FIG. 2, when the electrode catheter 1 has a tip 60 at the distal end of the shaft 10, the tip 60 has a tip connection member 61 connected to the tip 60, and the tip connection member 61 is preferably disposed in the lumen of the shaft 10. Examples of the tip connection member 61 include a pull wire for bending the distal side of the shaft 10 and a conductor 30 for the tip 60 to function as an electrode 20.

When the distal tip 60 has a distal tip connecting member 61, the connecting member connecting step of connecting the distal tip connecting member 61 to the distal tip 60 may be performed after the distal tip arrangement step, but is preferably performed before the distal tip arrangement step. By performing the connecting member connecting step before the distal tip arrangement step, it becomes easier to connect the distal tip connecting member 61 to the distal tip 60, and it becomes easier to reliably fix the distal tip connecting member 61 to the distal tip 60.

Although not shown, the electrode catheter 1 does not have to have a tip 60 at the distal end of the shaft 10. If the electrode catheter 1 does not have a tip 60, it is preferable to have a process of sealing the opening at the distal end of the shaft 10 by heat fusing the distal end of the shaft 10 or the like.

As shown in FIG. 5, the area of the bottom 12 of the recess 11 is preferably larger than the area of the hole 13 in a cross section perpendicular to the depth direction of the hole 13. By making the area of the bottom 12 of the recess 11 larger than the area of the hole 13, it is easier to form the hole 13 by piercing the first end 31 of the conductor 30 into the bottom 12.

The area of the bottom 12 of the recess 11 is preferably more than 1.0 times the area of the hole 13 in a cross section perpendicular to the depth direction of the hole 13, more preferably 1.1 times or more, even more preferably 1.3 times or more, and even more preferably 1.5 times or more. By setting the lower limit of the ratio of the area of the bottom 12 of the recess 11 to the area of the hole 13 in the above range, the size of the bottom 12 of the recess 11 can be sufficiently secured. Therefore, it is possible to easily pierce the first end 31 of the conductor 30 into the bottom 12 of the recess 11. In addition, the area of the bottom 12 of the recess 11 is preferably 10 times or less, more preferably 9 times or less, and even more preferably 8 times or less, the area of the hole 13 in a cross section perpendicular to the depth direction of the hole 13. By setting the upper limit of the ratio of the area of the bottom 12 of the recess 11 to the area of the hole 13 in the above range, the size of the hole 13 is less likely to become large. As a result, when the electrode 20 is placed outside the hole 13, it is easy for the electrode 20 to cover the entire hole 13.

As shown in FIG. 3, after the recess formation process, the depth D1 of the recess 11 is preferably longer than the shortest distance D2 from the bottom 12 of the recess 11 to the inner surface of the shaft 10. By making the depth D1 of the recess 11 longer than the shortest distance D2 from the bottom 12 of the recess 11 to the inner surface of the shaft 10, it becomes easier to pierce the first end 31 of the conductor 30 into the bottom 12 of the recess 11, making it easier to form the hole 13.

After the recess formation process, the depth D1 of the recess 11 is preferably 1.1 times or more, more preferably 1.5 times or more, and even more preferably 2.0 times or more, of the shortest distance D2 from the bottom 12 of the recess 11 to the inner surface of the shaft 10. By setting the lower limit of the ratio of the depth D1 of the recess 11 to the shortest distance D2 from the bottom 12 of the recess 11 to the inner surface of the shaft 10 within the above range, the thickness of the bottom 12 of the recess 11 can be made thin, making it easier to pierce the conductor 30 and form the hole 13. In addition, the depth D1 of the recess 11 is preferably 7 times or less, more preferably 6 times or less, and even more preferably 5 times or less, of the shortest distance D2 from the bottom 12 of the recess 11 to the inner surface of the shaft 10. By setting the upper limit of the ratio between the depth D1 of the recess 11 and the shortest distance D2 from the bottom 12 of the recess 11 to the inner surface of the shaft 10 within the above range, it is possible to easily insert the first end 31 of the conductor 30 while providing strength to the bottom 12 of the recess 11. As a result, even if the conductor 30 is pulled and a load is applied to the hole 13 when the conductor 30 is inserted into the inner cavity of the shaft 10, the hole 13 is less likely to tear, and it is possible to prevent a distance from increasing between the hole 13 and the conductor 30.

As shown in FIG. 7, the length L1 of the bottom 12 of the recess 11 in the longitudinal direction of the shaft 10 is preferably shorter than the length L2 of the electrode 20 in the longitudinal direction of the shaft 10. Because the length L1 of the bottom 12 of the recess 11 is shorter than the length L2 of the electrode 20, when the electrode 20 is placed outside the hole 13, the electrode 20 can cover the entire bottom 12 of the recess 11. Therefore, a gap is less likely to occur between the inner surface of the electrode 20 and the bottom 12 of the recess 11, making it less likely for liquids such as blood to seep in through this gap.

The length L1 of the bottom 12 of the recess 11 in the longitudinal direction of the shaft 10 is preferably 70% or less, more preferably 50% or less, and even more preferably 30% or less, of the length L2 of the electrode 20 in the longitudinal direction of the shaft 10. By setting the upper limit of the ratio between the length L1 of the bottom 12 of the recess 11 and the length L2 of the electrode 20 within the above range, the bottom 12 of the recess 11 is less likely to be exposed from the electrode 20 after the electrode 20 is placed outside the hole 13, and liquids such as blood are less likely to penetrate into the bottom 12 of the recess 11. The lower limit of the ratio between the length L1 of the bottom 12 of the recess 11 and the length L2 of the electrode 20 is not particularly limited, but can be, for example, 1% or more, 2% or more, or 3% or more.

As shown in FIG. 5, the area of the bottom 12 of the recess 11 is preferably larger than the cross-sectional area perpendicular to the longitudinal axis of the conductor 30. By having the area of the bottom 12 of the recess 11 larger than the cross-sectional area of the conductor 30, it becomes easier to pierce the first end 31 of the conductor 30 into the bottom 12 to form a hole 13.

The area of the bottom 12 of the recess 11 is preferably 1.1 times or more, more preferably 1.3 times or more, and even more preferably 1.5 times or more, of the cross-sectional area perpendicular to the longitudinal axis direction of the conductor 30. By setting the lower limit of the ratio of the area of the bottom 12 of the recess 11 to the cross-sectional area of the conductor 30 within the above range, it becomes easier to pierce the first end 31 of the conductor 30 into the bottom 12 of the recess 11. In addition, the area of the bottom 12 of the recess 11 is preferably 10 times or less, more preferably 9 times or less, and even more preferably 8 times or less, of the cross-sectional area perpendicular to the longitudinal axis direction of the conductor 30. By setting the upper limit of the ratio of the area of the bottom 12 of the recess 11 to the cross-sectional area of the conductor 30 within the above range, the size of the hole 13 formed by piercing the conductor 30 into the bottom 12 is less likely to become large, and when the electrode 20 is placed outside the hole 13, the entire hole 13 can be covered by the electrode 20.

As shown in FIG. 7, after the electrode placement process, the second end 32 of the conductor 30 is preferably located outside the shaft 10. The second end 32 of the conductor 30 being located outside the shaft 10 can be said to be not located in the lumen of the shaft 10. By having the second end 32 of the conductor 30 located outside the shaft 10, the surface area of the conductor 30 to be inserted into the tube wall of the shaft 10 can be reduced. As a result, the number of holes 13 for inserting the conductor 30 into the lumen of the shaft 10 can be reduced, and the size of the holes 13 can be reduced, and the paths for liquids such as blood to enter the lumen of the shaft 10 can also be reduced. Also, for example, when the connection between the conductor 30 and the electrode 20 is made by welding, and the distance between the welded portion between the conductor 30 and the electrode 20 and the second end 32 of the conductor 30 is short, the second end 32 of the conductor 30 is located outside the shaft 10, so that the distance between the welded portion between the conductor 30 and the electrode 20 and the hole 13 can be increased, and it is possible to prevent the welded portion between the conductor 30 and the electrode 20 from pushing the hole 13 wide and creating a gap.

Although not shown, it is preferable to have a wire bonding process in which the wire 30 is fixed to the hole 13 with an adhesive after the hole forming process. By fixing the wire 30 to the hole 13 with an adhesive, the adhesive is present between the hole 13 and the wire 30, making it even less likely that a gap will occur between the hole 13 and the wire 30. In addition, by firmly fixing the wire 30 to the hole 13 with an adhesive, when a load is applied to the wire 30, for example when the shaft 10 of the electrode catheter 1 is bent and the wire 30 is pulled, it is possible to prevent the wire 30 from being applied to the hole 13 by the wire 30 and tearing the hole 13.

As an adhesive for bonding and fixing the conductor 30 to the hole 13, it is preferable to use a polyurethane-based, epoxy-based, cyano-based, fluorine-based, or silicone-based adhesive.

Next, we will explain the electrode catheter of the present invention. Note that in the following explanation, parts that overlap with the above explanation will be omitted.

As shown in Figures 1 and 2, the electrode catheter 1 has a shaft 10 that extends in the longitudinal direction and has an inner cavity, a hole 13 that connects the inner cavity to the outer surface, an electrode 20 that is disposed outside the hole 13, and a conductor 30 that is connected to the electrode 20 and extends into the inner cavity of the shaft 10 through the hole 13. The shaft 10 has a bottomed recess 11 in the tube wall of the shaft 10, the hole 13 is provided in the bottom 12 of the recess 11, the bottom 12 of the recess 11 is circular, and the area of the bottom 12 of the recess 11 is smaller than the area of the inner surface of the electrode 20.

The bottom 12 of the recess 11 is circular, as shown in FIG. 5. In other words, the shape of the bottom 12 of the recess 11 when viewed from a direction perpendicular to the bottom 12 is circular. Note that a circular shape includes a perfect circle, an ellipse, an oval, and an egg shape.

The shaft 10 has a bottomed recess 11, and a hole 13 is provided in the bottom 12, so that the outer surface of the shaft 10 is less likely to come into contact with the connection point between the conductor 30 inserted in the hole 13 and the electrode 20. As a result, it is possible to prevent the shaft 10 from being partially distorted due to the connection point between the conductor 30 and the electrode 20 being pressed against the shaft 10, which makes it easier for a gap to form between the electrode 20 and the outer surface of the shaft 10. In addition, by preventing distortion of the shaft 10, it is possible to prevent the inner cavity of the shaft 10 from collapsing. By preventing the inner cavity of the shaft 10 from collapsing, it is possible to ensure space when placing an internal structure such as the conductor 30 in the inner cavity of the shaft 10 during the manufacture of the electrode catheter 1, making it easier to place the internal structure, and to make it less likely for the internal structure placed in the inner cavity of the shaft 10 to be damaged.

By having the bottom 12 of the recess 11 be circular, it is easy to form a bottomed recess 11 in the shaft 10, and the size of the bottom 12 is not made too large, making it difficult for the connection point between the conductor 30 and the electrode 20 to come into contact with the outer surface of the shaft 10. Specifically, as shown in Figs. 2 and 7, the connection point between the conductor 30 and the electrode 20 fits into the recess 11, making it difficult for the connection point between the conductor 30 and the electrode 20 to come into contact with the outer surface of the shaft 10. For example, when connecting the conductor 30 to the electrode 20 by welding or the like, even if the connection point between the conductor 30 and the electrode 20 deviates from the target position, the connection point between the conductor 30 and the electrode 20 is likely to fit into the recess 11.

The area of the bottom 12 of the recess 11 is smaller than the area of the inner surface of the electrode 20, so that the electrode 20 can cover the entire bottom 12 of the recess 11. As a result, gaps are less likely to form between the inner surface of the electrode 20 and the bottom 12 of the recess 11, and it is possible to prevent liquids such as blood from entering through these gaps.

When the electrode 20 is a ring-shaped electrode, the inner diameter of the electrode 20 is preferably smaller than the outer diameter of the shaft 10. By making the inner diameter of the electrode 20 smaller than the outer diameter of the shaft 10, the end of the electrode 20 is less likely to get caught on other objects, and the inner walls of blood vessels and the heart are less likely to be damaged. To make the inner diameter of the electrode 20 smaller than the outer diameter of the shaft 10, for example, the inner diameter of the electrode 20 is formed larger than the outer diameter of the shaft 10, the electrode 20 is passed through the shaft 10, and the electrode 20 is crimped from the outside to reduce the inner diameter of the electrode 20, or the shaft 10 is formed of a thermally expandable resin with an outer diameter smaller than the inner diameter of the electrode 20, the electrode 20 is passed through the shaft 10, the shaft 10 is heated, and the outer diameter of the shaft 10 is increased.

As shown in FIG. 1, the electrode catheter 1 may have a handle 50 on the proximal side. By having the handle 50 on the electrode catheter 1, it becomes easier to operate the electrode catheter 1.

As shown in FIG. 2, in the portion of the hole 13 in the lumen of the shaft 10, the inner wall of the shaft 10 preferably protrudes toward the center of the longitudinal axis of the shaft 10. In other words, in the portion of the hole 13 in the lumen of the shaft 10, the inner wall of the shaft 10 preferably protrudes toward the center of the longitudinal axis of the shaft 10. In the portion of the hole 13 in the lumen of the shaft 10, the inner wall of the shaft 10 protrudes toward the center of the longitudinal axis of the shaft 10, so that when the distal side of the shaft 10 of the electrode catheter 1 is bent, etc., and the conductor 30 is pulled, the conductor 30 contacts this protruding portion before the outer side of the shaft 10 of the hole 13, and a load is applied. As a result, the conductor 30 is less likely to deform the hole 13 on the outer side of the shaft 10, and a gap is less likely to occur between the hole 13 and the conductor 30, making it difficult for liquids such as blood to enter the lumen of the shaft 10. In other words, when the conductor 30 is pulled, the conductor 30 and the protruding portion come into contact before the conductor 30 and the hole 13 do, so the hole 13 is less likely to deform and a gap is less likely to form between the hole 13 and the conductor 30, and as a result, liquids such as blood are less likely to enter the lumen of the shaft 10.

As described above, the manufacturing method of the electrode catheter of the present invention includes a preparation step of preparing a shaft extending in the longitudinal direction and having an inner cavity, an electrode, and a conductor; a recess forming step of forming a bottomed recess in the tubular wall of the shaft; a hole forming step of inserting a first end of the conductor into the bottom of the recess to form a hole in the shaft that connects the inner cavity to the outside; a conductor connecting step of connecting a second end of the conductor to the electrode; and an electrode placement step of placing the electrode on the outside of the hole. By including these steps in the manufacturing method of the electrode catheter of the present invention, it is possible to easily manufacture an electrode catheter that is less likely to have a gap between the conductor and the hole, and is less likely to allow liquids such as blood to penetrate into the inner cavity of the shaft.

The electrode catheter of the present invention has a shaft that extends in the longitudinal direction and has an inner cavity, a hole that connects the inner cavity to the outer surface, an electrode that is disposed outside the hole, and a conductor that is connected to the electrode and extends into the inner cavity of the shaft through the hole, and the shaft has a bottomed recess in the tubular wall of the shaft, the hole is provided at the bottom of the recess, the bottom of the recess is circular, and the area of the bottom of the recess is smaller than the area of the inner surface of the electrode. Because the electrode catheter of the present invention has such a configuration, it is difficult for a gap to occur between the conductor and the hole, and liquids such as blood to enter the inner cavity of the shaft.

1: Electrode catheter 10: Shaft 11: Recess 12: Bottom 13: Hole 20: Electrode 30: Conductor 31: First end 32: Second end 50: Handle 60: Distal tip 61: Distal tip connection member D1: Depth of recess D2: Shortest distance from bottom of recess to inner surface of shaft L1: Length of bottom of recess L2: Length of electrode

Claims (14)

A preparation step of providing a shaft extending in a longitudinal direction and having an internal lumen, an electrode, and a lead;
a recess forming step of forming a bottomed recess in a tube wall of the shaft;
a hole forming step of inserting a first end of the conductive wire into a bottom of the recess to form a hole in the shaft that communicates with the inner cavity and the outside;
a conductor connection step of connecting a second end of the conductor to the electrode;
and an electrode positioning step of positioning the electrode outside the hole. The method for manufacturing an electrode catheter according to claim 1, wherein the area of the bottom of the recess is greater than the area of the hole in a cross section perpendicular to the depth direction of the hole. The method for manufacturing an electrode catheter according to claim 1 or 2, wherein after the recess forming step, the depth of the recess is longer than the shortest distance from the bottom of the recess to the inner surface of the shaft. The method for manufacturing an electrode catheter according to any one of claims 1 to 3, wherein the length of the bottom of the recess in the longitudinal direction of the shaft is shorter than the length of the electrode in the longitudinal direction of the shaft. The method for manufacturing an electrode catheter according to any one of claims 1 to 4, wherein the area of the bottom of the recess is greater than the cross-sectional area perpendicular to the longitudinal axis of the conductor. The method for manufacturing an electrode catheter according to any one of claims 1 to 5, wherein after the electrode placement process, the second end of the conductor is located outside the shaft. The method for manufacturing an electrode catheter according to any one of claims 1 to 6, further comprising a wire bonding step of fixing the wire to the hole with an adhesive after the hole forming step. A shaft extending in a longitudinal direction and having an inner lumen, the shaft having a hole communicating between the inner lumen and an outer surface of the shaft;
an electrode disposed outside the hole;
a conductor connected to the electrode and extending through the hole into the lumen of the shaft;
The shaft has a bottomed recess in a tube wall of the shaft,
The hole is provided at the bottom of the recess,
The bottom of the recess is circular,
An electrode catheter, wherein the area of the bottom of the recess is smaller than the area of the inner surface of the electrode. The electrode catheter according to claim 8, wherein the area of the bottom of the recess is greater than the area of the hole in a cross section perpendicular to the depth direction of the hole. The electrode catheter according to claim 8 or 9, wherein the depth of the recess is greater than the shortest distance from the bottom of the recess to the inner surface of the shaft. An electrode catheter according to any one of claims 8 to 10, wherein the length of the bottom of the recess in the longitudinal direction of the shaft is shorter than the length of the electrode in the longitudinal direction of the shaft. An electrode catheter according to any one of claims 8 to 11, wherein the area of the bottom of the recess is greater than the cross-sectional area perpendicular to the longitudinal axis of the conductor. An electrode catheter according to any one of claims 8 to 12, wherein the second end of the conductor is located outside the shaft. An electrode catheter according to any one of claims 8 to 13, wherein the inner wall of the shaft protrudes toward the center of the longitudinal axis of the shaft in the portion of the hole in the inner cavity of the shaft.

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