WO2025115280A1 - Electrode catheter - Google Patents

Abstract

This electrode catheter comprises: a shaft to be inserted into the body; and an electrode assembly 16 provided at the leading end of the shaft. The electrode assembly 16 is provided with a plurality of splines 24a-24f each having at least one electrode 26, and a leading end member connected to the leading end sides of the plurality of splines 24a-24f. The plurality of splines 24a-24f can be deformed into a circular sector shape having arc-shaped regions 28a-28f along a common virtual circle 50 as viewed in the axial direction of the shaft. When the plurality of splines 24a-24f are in the circular sector shape, the plurality of arc-shaped regions 28a-28f formed by the plurality of splines 24a-24f account for a total of at least 80% of the circumference of the virtual circle 50.

Description

Electrode Catheter

This disclosure relates to an electrode catheter.

A catheter is a type of medical device that is inserted into the body for diagnosis or treatment. As an example, an electrode catheter is known that includes a shaft and a basket electrode assembly connected to the tip of the shaft (see, for example, Patent Document 1). Here, the basket electrode assembly includes a number of splines. The basket electrode assembly is configured to be deformed from a contracted shape to an expanded shape by deforming the splines.

Special Publication No. 2016-507349

The electrode catheter described above has difficulty in simultaneously contacting most of the inner circumference of tubular body tissue. For this reason, for example, when cauterizing the boundary between the pulmonary vein and the left atrium to treat atrial fibrillation, it is necessary to cauterize multiple times while changing the position of the spline.

The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide an electrode catheter that can be simultaneously contacted over most of the inner circumference of tubular body tissue.

One aspect of the present disclosure is an electrode catheter. The electrode catheter comprises a shaft that is inserted into the body and an electrode assembly provided at the tip of the shaft. The electrode assembly comprises a plurality of splines, each having at least one electrode, and a tip member connected to the tip side of the plurality of splines. Each of the plurality of splines can be deformed into a fan shape having an arc-shaped region along a common imaginary circle when viewed from the axial direction of the shaft, and when each of the plurality of splines is fan-shaped, the plurality of arc-shaped regions formed by the plurality of splines collectively occupy 80% or more of the circumference of the imaginary circle.

Another aspect of the present disclosure is an electrode catheter. This electrode catheter comprises a shaft that is inserted into the body and an electrode assembly provided at the tip of the shaft. The electrode assembly comprises a number of splines, each having at least one electrode, and a tip member connected to the tip side of the number of splines. With the number of splines in contact with the inner wall of the boundary between the pulmonary vein and the left atrium, an electrical pulse can be applied through the number of electrodes, thereby cauterizing the electrical transmission pathway of atrial fibrillation so as to block it all at once.

Any combination of the above components, or any conversion of the expressions of this disclosure between methods, devices, systems, etc., are also valid aspects of this disclosure.

The electrode catheter of the present disclosure can simultaneously contact most of the inner circumference of tubular body tissue.

FIG. 1 is an explanatory diagram relating to a usage scene of the electrode catheter according to the first embodiment. FIG. 2 is a side view showing a schematic view of the vicinity of the tip of the electrode catheter shown in FIG. 1. FIG. 2 is a view of the electrode catheter shown in FIG. 1 as seen from the tip side in the axial direction of the shaft. FIG. 2 is a schematic diagram showing the boundary between the pulmonary vein and the left atrium cauterized by the electrode catheter shown in FIG. 1 . FIG. 2 is a side view showing a schematic example of the overall configuration of the electrode catheter shown in FIG. 1 . 13 is a side view showing a schematic view of the vicinity of the tip of an electrode catheter according to a second embodiment. FIG. FIG. 7 is a view of the electrode catheter shown in FIG. 6 as seen from the tip side in the axial direction of the shaft.

Below, the present disclosure will be described with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing will be given the same reference numerals, and duplicated descriptions will be omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are intended to distinguish one configuration from another. In addition, some of the members that are not important in explaining the embodiments in each drawing are omitted.

[First embodiment]
FIG. 1 is an explanatory diagram of a usage scene of the electrode catheter 10 according to the first embodiment of the present disclosure. The electrode catheter 10 is used for treatment of a living body. Here, "treatment" refers to an action related to medical treatment or examination of a living body. The electrode catheter 10 of this embodiment is used for treatment of atrial fibrillation by PFA (Pulsed Field Ablation). Atrial fibrillation is often caused by the transmission of abnormal electrical signals generated in the pulmonary vein 112 to the left atrium 114. This treatment is usually performed by cauterizing the boundary between the pulmonary vein 112 and the left atrium 114 using the electrode assembly 16 of the electrode catheter 10. Here, the ablation range Sa by the electrode catheter 10 is hatched. This blocks the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114. The method of current application using the electrode assembly 16 can be a monopolar method in which current is applied between the electrode assembly 16 and a return electrode plate placed outside the body, or a bipolar method in which current is applied between the electrode assembly 16 and another electrode placed inside the body. 1 shows an annular ablation area Sa, but the ablation area Sa indicates an approximate area to be ablated by the electrode catheter 10, and the actual ablation area does not necessarily have to coincide with the ablation area Sa. The details of the ablation area Sa will be described later.

2 is a side view showing the tip of the electrode catheter 10. The electrode catheter 10 includes a shaft 20 that is inserted into the body and an electrode assembly 16 that is provided at the tip of the shaft 20. FIG. 3 is a view of the electrode catheter 10 as seen from the tip side in the axial direction of the shaft 20. In the following, the side of the electrode catheter 10 that is inserted into the body is referred to as the "tip side" and the side that is placed outside the body is referred to as the "base side". In addition, for each member that constitutes the electrode catheter 10, the same side as the tip side of the electrode catheter 10 is referred to as the "tip side" of that member, and the same side as the base side of the electrode catheter 10 is referred to as the "base side" of that member. In this specification, "viewed from the tip side in the axial direction" means that the electrode catheter 10 is viewed toward the base side from a viewpoint located on the tip side of the electrode catheter 10 along the axial direction of the shaft 20.

The shaft 20 may be a long, tubular member. The length of the shaft 20 is, for example, 800 mm to 1800 mm. The outer diameter of the shaft 20 is, for example, 2.0 mm to 5.0 mm. The material constituting the shaft 20 may be any material that is flexible and biocompatible. For example, the shaft 20 is made of a known resin such as polyolefin or polyamide elastomer.

The electrode assembly 16 comprises a plurality of splines 24a-24f and a tip member 22 that is connected to the tip side of the plurality of splines 24a-24f by attachment or the like. In the following, descriptions common to each of the plurality of splines 24a-24f will also be simply referred to as spline 24. For other reference numerals with an alphabetical character added to the end, descriptions common to those reference numerals will be written without the alphabetical character added as appropriate.

The spline 24 is a member that connects the shaft 20 and the tip member 22. The spline 24 may be a cylindrical member, similar to the shaft 20. The length of the spline 24 when extended in a straight line is, for example, 20 mm to 70 mm. The outer diameter of the spline 24 is, for example, 0.5 mm to 2.0 mm. The material that constitutes the spline 24 may be any material that is flexible and biocompatible. For example, the spline 24, similar to the shaft 20, is made of a known resin such as polyolefin or polyamide elastomer.

The electrode catheter 10 according to this embodiment has six splines 24a to 24f. The splines 24a to 24f are arranged adjacent to each other in the stated order in a clockwise direction along the circumferential direction when viewed from the tip side. That is, spline 24a and spline 24b, spline 24b and spline 24c, spline 24c and spline 24d, spline 24d and spline 24e, spline 24e and spline 24f, and spline 24f and spline 24a are adjacent to each other. In addition, near the center of the splines 24 in the axial direction of the shaft 20, the splines 24 are arranged spaced apart from each other in a plane perpendicular to the central axis of the shaft 20.

The base end side of the spline 24 is connected to the shaft 20. As an example, a part including the base end of the spline 24 (hereinafter referred to as the "base end") is inserted into the tip side of the shaft 20 and bundled. The base end side of the spline 24 and the shaft 20 are then joined to each other by a known joining method such as welding or bonding with an adhesive.

The tip member 22 may cover and bundle a portion (hereinafter referred to as the "tip portion") including the tip of each of the multiple splines 24a to 24f. In other words, the tip portions of the multiple splines 24a to 24f may be covered with the tip member 22. The tip member 22 may be in any shape, and is cap-shaped as an example. The tip member 22 may be made of any material, and is made of known resins such as polyamide, polyamide elastomer, polycarbonate, etc., or known metals such as stainless steel, etc. The inside of the tip member 22 may be filled with adhesive. In this case, the multiple splines 24a to 24f are likely to be firmly fixed to each other by the adhesive.

The shape of the splines 24 changes in response to a deformation operation, which will be described later. In other words, the splines 24 are configured to be deformable. Specifically, the shape of each spline 24 changes between a non-deployed or contracted shape in which the splines 24 are not deployed along the central axis of the shaft 20, and an expanded or expanded shape in which the splines 24 are deployed from the contracted shape along the central axis of the shaft 20. Details will be described later, but an example of a contracted shape is a "petal shape." On the other hand, an example of an expanded shape is a "basket shape" in which the splines 24 are deployed from the petal shape along the central axis of the shaft 20. Both Figures 2 and 3 show the state in which each spline 24 is deformed into the expanded shape.

Each of the multiple splines 24a to 24f has at least one electrode 26. The electrode 26 is, for example, a ring-shaped electrode provided on the outer peripheral surface of the spline 24. The electrodes 26 of the same spline 24 are arranged at a distance from each other along the longitudinal direction of the spline 24. In this case, the distance between adjacent electrodes 26 may be constant or may be different. Also, the number of electrodes 26 that each spline 24 has may be the same or may be different. In this embodiment, the distance between adjacent electrodes 26 is constant, and all of the electrodes 26 are arranged within a certain area that includes the longitudinal center of each spline 24. Each of the multiple splines 24a to 24f according to this embodiment has four electrodes 26.

The electrode 26 is made of a conductive material. For example, the electrode 26 is made of a metal with good electrical conductivity, such as aluminum (Al), copper (Cu), stainless steel, gold (Au), or platinum (Pt). The length of the electrode 26 along the longitudinal direction of the spline 24 is, for example, 0.5 mm to 2.0 mm. The outer diameter of the electrode 26 may be the same as the outer diameter of the spline 24, and is, for example, 0.5 mm to 2.0 mm.

The electrodes 26 are individually and electrically connected to conductors. The conductors pass from inside the spline 24 through the shaft 20 and the handle 8 (described below), and are connected to an external power supply device via the handle 8.

3, when the splines 24a to 24f are in an expanded shape, the splines 24a to 24f form a plurality of arc-shaped regions 28a to 28f along a common imaginary circle 50 as viewed from the axial direction of the shaft 20. Specifically, the spline 24a forms the arc-shaped region 28a along a portion of the imaginary circle 50. Similarly, the splines 24b to 24f each form an arc-shaped region 28b to 28f along a portion of the imaginary circle 50. The formation of the arc-shaped regions 28a to 28f along the common imaginary circle 50 by the splines 24a to 24f is not limited to when the splines 24a to 24f are in an expanded shape. The shape when each of the splines 24a to 24f has an arc-shaped region 28 along the common imaginary circle 50 is also called a sector shape. In other words, each of the multiple splines 24a to 24f can be deformed into a sector shape having an arc-shaped region 28 that is aligned with a common imaginary circle 50 when viewed from the axial direction of the shaft 20. Here, the arc-shaped region 28 that is aligned with the imaginary circle 50 when viewed from the axial direction of the shaft 20 means that the arc-shaped region 28 overlaps with the imaginary circle 50 when viewed from the axial direction of the shaft 20, and the longitudinal direction of the spline 24 in the arc-shaped region 28 approximately coincides with the circumferential direction of the imaginary circle 50 when viewed from the axial direction of the shaft 20.

In this embodiment, the center of the virtual circle 50 is located at the center of the tip member 22 when viewed from the axial direction of the shaft 20. In this embodiment, the arc-shaped region 28 constitutes a certain region including the center of the spline 24 in the longitudinal direction. Specifically, when the spline 24 is fan-shaped, the spline 24 includes the arc-shaped region 28, a region extending from the tip member 22 in the radial direction of the virtual circle 50 and connecting to one end of the arc-shaped region 28, and a region extending from the shaft 20 in the radial direction of the virtual circle 50 and connecting to the other end of the arc-shaped region 28. In addition, in this embodiment, the arc-shaped region 28 constitutes the region of the spline 24 that is the farthest from the center of the virtual circle 50 when viewed from the axial direction of the shaft 20. That is, in this embodiment, the virtual circle 50 is a virtual circle that can be drawn on the outermost periphery of the spline 24 when viewed from the axial direction of the shaft 20.

When each of the splines 24a to 24f is fan-shaped, the arc-shaped regions 28a to 28f formed by the splines 24a to 24f occupy 80% or more of the circumference of the virtual circle 50 as a whole. In other words, the ratio of the arc-shaped regions 28a to 28f to the circumference of the virtual circle 50 as a whole is 80% or more of the circumference of the virtual circle 50. Therefore, the splines 24a to 24f can be simultaneously contacted over most of the circumferential direction of the inner wall of the tubular body tissue, such as the boundary between the pulmonary vein 112 and the left atrium 114 shown in FIG. 1. Therefore, the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 can be blocked by a single cauterization without changing the positions of the splines 24a to 24f. In this embodiment, as shown in FIG. 3, the arc-shaped regions 28a to 28f overlap with the virtual circle 50 over almost the entire circumference of the virtual circle 50 as viewed from the axial direction of the shaft 20.

As shown in FIG. 3, when each of the splines 24a to 24f is fan-shaped, at least two adjacent splines of the splines 24a to 24f, for example, spline 24a and spline 24b, have an overlap region 30 where they overlap when viewed from the axial direction of the shaft 20. Specifically, spline 24a and spline 24b cross each other in the overlap region 30 when viewed from the axial direction of the shaft 20. The overlap region 30 is also included in the arc-shaped region 28. Therefore, adjacent splines 24 are arranged without any gaps when viewed from the axial direction of the shaft 20, so that the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 can be blocked more reliably. In this embodiment, not only spline 24a and spline 24b but all adjacent splines 24 have the overlap region 30.

In this embodiment, when each of the multiple splines 24a to 24f is fan-shaped, only adjacent splines 24 have a common overlap region 30 where they overlap when viewed in the axial direction of the shaft 20. In other words, non-adjacent splines 24 do not overlap when viewed in the axial direction of the shaft 20 and do not have an overlap region 30. Therefore, it is not necessary for the splines 24 to have a shape that is excessively twisted around the central axis of the shaft 20.

As shown in FIG. 3, the tip member 22 fixes at least two adjacent splines 24, for example, spline 24a and spline 24b, among the plurality of splines 24, at a predetermined angular interval α around the central axis of the shaft 20. The shaft 20 also fixes the at least two adjacent splines 24, for example, spline 24a and spline 24b, at a position rotated relative to the tip member 22 by an angle between 1 and 3 times the angular interval α around the central axis of the shaft 20.

3, the twist angle β is the clockwise angle at the position where the spline 24a is fixed to the shaft 20, based on the position where the spline 24a is fixed to the tip member 22. Similarly, the spline 24b is fixed to the shaft 20 at a position rotated clockwise by the twist angle β from the position where the spline 24b is fixed to the tip member 22. In this case, the twist angle β is 1 to 3 times the angle interval α. By making the twist angle β 1 or more times the angle interval α, it becomes easier to form the overlap region 30, and therefore it becomes easier to block the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114. By making the twist angle β 3 times or less the angle interval α, it becomes possible to avoid the spline 24 being excessively twisted around the central axis of the shaft 20.

In this embodiment, the above-mentioned relationship between the angular interval α and the twist angle β is satisfied not only for spline 24a and spline 24b but also for all adjacent splines 24. In this case, since there are six splines 24a to 24f in this embodiment, the angular interval α may be approximately 60°. Furthermore, the twist angle β may be approximately 60° or more and approximately 180° or less.

As shown in FIG. 3, when each of the splines 24a to 24f is fan-shaped, the electrodes 26 of the splines 24a to 24f that are located in the arc-shaped regions 28a to 28f are arranged at equal intervals on the circumference of the imaginary circle 50. Specifically, each of the splines 24a to 24f has four electrodes 26, which are arranged at equal intervals along the longitudinal direction of each spline 24 as viewed from the axial direction of the shaft 20. The electrodes 26 that are closest to each other on adjacent splines 24 are arranged at approximately the same intervals as the electrodes 26 of each spline 24 as viewed from the axial direction of the shaft 20. In this case, the electrodes 26 being evenly spaced means that the difference between the interval between any two adjacent electrodes 26 and the average interval between all adjacent electrodes 26 on a plane viewed from the axial direction of the shaft 20 as shown in FIG. 3 is less than 10%, for example. When each of the multiple splines 24a-24f is fan-shaped, each of the multiple splines 24a-24f may have one or more electrodes 26 arranged in an area other than the arc-shaped area 28.

When each of the multiple splines 24a to 24f is fan-shaped, the multiple electrodes 26 of the multiple splines 24a to 24f may be disposed at positions corresponding to multiple imaginary points that are equally spaced around the circumference of an imaginary circle 50, as viewed in the axial direction of the shaft 20. In this case, the electrodes 26 being disposed at positions corresponding to the imaginary points means that at least a portion of the electrodes 26 is disposed at a position that overlaps with the imaginary points as viewed in the axial direction of the shaft 20.

As shown in FIG. 2, when each of the multiple splines 24a to 24f is fan-shaped, the arc-shaped region 28 of each spline 24 is located in a region that includes the center of the spline 24 in the axial direction. The arc-shaped region 28 of each spline 24 is located in a region that is within 90% of the total axial length of the electrode assembly 16, and preferably within 80%. Each spline 24 tends to be largest in the radial direction perpendicular to the axial direction near the center in the axial direction. Since the arc-shaped region 28 is located in such a region, it is easy to reliably bring the arc-shaped region 28 into contact with the inner circumference of tubular body tissue, such as the boundary between the pulmonary vein 112 and the left atrium 114 shown in FIG. 1.

As described above, the electrode catheter 10 according to the first embodiment has been described as having six splines 24a to 24f. However, the number of splines 24 provided on the electrode catheter 10 is not limited to six, and may be four or more.

FIG. 4 is a schematic diagram showing the boundary 116 between the pulmonary vein 112 and the left atrium 114, which is cauterized by the electrode catheter 10. When treating atrial fibrillation, the electrode catheter 10 enters the boundary 116 from inside the left atrium 114, with the tip of the electrode catheter 10 facing the pulmonary vein 112. At this time, each of the multiple splines 24a to 24f is deformed into a fan shape, and the multiple splines 24a to 24f are brought into contact with the inner wall of the boundary 116. In this state, when an electrical pulse is applied through the multiple electrodes 26, the boundary 116 is cauterized at multiple cauterization points 130. The multiple cauterization points 130 are included in the cauterization range Sa also shown in FIG. 1.

The ablation points 130 correspond to the locations where the splines 24a-24f contact the boundary 116. The locations where the splines 24a-24f contact the boundary 116 are mainly the arc-shaped regions 28. That is, the ablation points 130 are formed to correspond to the shapes and arrangement of the arc-shaped regions 28. The transmission path 118 of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 associated with atrial fibrillation tends to be a straight path from the pulmonary vein 112 to the left atrium 114 along the myocardial sleeve formed at the boundary 116, as shown in FIG. 4. Therefore, the ablation points 130 formed to correspond to the shapes and arrangement of the arc-shaped regions 28 can block the transmission path 118 of abnormal electrical signals.

In this way, by using the electrode catheter 10 of this embodiment, the multiple splines 24a-24f are in contact with the inner wall of the boundary 116 between the pulmonary vein 112 and the left atrium 114, and an electrical pulse is applied through the multiple electrodes 26, thereby cauterizing the electrical transmission pathway 118 of atrial fibrillation so as to block it all at once.

FIG. 5 is a side view showing a schematic example of the overall configuration of the electrode catheter 10. As shown in FIG. 5, the electrode catheter 10 may include a handle 8 connected to the base end side of the shaft 20. The handle 8 is a part that an operator such as a doctor grasps or holds when using the electrode catheter 10. The handle 8 may include a handle main body 11 attached to the base end side of the shaft 20, a rotation operation unit 12, and a slide member 13.

The handle body 11 corresponds to the part that the operator actually grips. The handle body 11 may have any shape. As an example, the handle body 11 has a shape that extends along the central axis of the shaft 20. The handle body 11 is made of a known resin, such as polycarbonate, polyacetal, ABS, etc.

The rotation operation unit 12 is the part that is operated by rotation operation and the like when bending or flexing the vicinity of the tip of the shaft 20 in both directions. The base ends of a pair of pull wires are fixed to the rotation operation unit 12 within the handle body 11. The tips of the pair of pull wires pass from inside the handle body 11 through the shaft 20 and are fixed to the tip side of the shaft 20. Therefore, when the rotation operation unit 12 is operated, the pull wires are pulled toward the base end, and the tip side of the shaft 20 to which the tips of the pull wires are fixed bends or flexes.

The slide member 13 is a part that is deformed by an operator, such as by sliding, when changing the shape of the multiple splines 24 between the undeployed or contracted shape and the deployed or expanded shape described above. The slide member 13 is slidable along the central axis of the shaft 20 in the handle body 11.

The base end of the deformation member 14 is fixed to the slide member 13. The tip of the deformation member 14 passes from inside the handle body 11 through the shaft 20 and is fixed in the tip member 22. The slide member 13 can be moved to any position along the central axis of the shaft 20 in the handle body 11. Therefore, depending on the position of the slide member 13, the shape of the multiple splines 24 can be deformed to the previously described non-expanded shape or contracted shape, the expanded shape or expanded shape, or any intermediate shape between the non-expanded shape and the expanded shape.

The deformation member 14 may be of any shape, structure, or material as long as it is long. As an example, the deformation member 14 is a wire.

[Second embodiment]
A second embodiment of the present disclosure will be described with reference to Figures 6 and 7. In the following embodiments, among the components described in the first embodiment, the same content as in the first embodiment may be applied to the components not described below. Figure 6 is a side view showing the vicinity of the tip of the electrode catheter 10A according to the second embodiment. Figure 7 is a view of the electrode catheter 10A as seen from the tip side in the axial direction of the shaft 20.

The electrode catheter 10A of this embodiment differs from the electrode catheter 10 of the first embodiment in the arrangement of the electrodes 26 of each of the splines 24a to 24f. That is, when each of the splines 24a to 24f is fan-shaped, at least a portion of the electrode 26 of one of at least two adjacent splines 24, for example, spline 24a and spline 24b, overlaps with at least a portion of the electrode 26 of the other spline 24 when viewed from the axial direction of the shaft 20. Specifically, as shown in FIG. 7, the electrode 261 of the spline 24a and the electrode 262 of the spline 24b overlap with each other when viewed from the axial direction of the shaft 20. As a result, by cauterizing using these electrodes 26, the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 can be more reliably blocked.

In this embodiment, the electrode 261 located closest to the spline 24b among the electrodes 26 of the spline 24a and the electrode 262 located closest to the spline 24a among the electrodes 26 of the spline 24b overlap each other when viewed from the axial direction of the shaft 20. This configuration can minimize the number of overlapping electrodes 26 while still achieving the effect of blocking the transmission of abnormal electrical signals.

In this embodiment, when each of the multiple splines 24a to 24f is fan-shaped, the multiple electrodes 26 of the multiple splines 24a to 24f do not have to be equally spaced on the circumference of the virtual circle 50 when viewed in the axial direction of the shaft 20. However, if the overlapping electrodes 26 of adjacent splines 24 are considered to be one electrode 26, it is also possible to arrange the electrodes 26 at equal intervals on the circumference of the virtual circle 50 when viewed in the axial direction of the shaft 20.

The above describes the embodiments of the present disclosure in detail. The above-mentioned embodiments merely show specific examples of implementing the present disclosure. The contents of the embodiments do not limit the technical scope of the present disclosure, and many design changes such as changes, additions, and deletions of components are possible within the scope of the idea of the present disclosure defined in the claims. A new embodiment with design changes has the effects of each of the combined embodiments and modifications. In the above-mentioned embodiments, the contents for which such design changes are possible are emphasized by adding notations such as "in this embodiment" and "in this embodiment", but design changes are permitted even in contents without such notations. Any combination of components included in each embodiment is also valid as an aspect of the present disclosure. Hatching on the cross sections of the drawings does not limit the material of the objects to which the hatching is applied.

The embodiment may be specified by the items described below.

[First item]
A shaft (20) to be inserted into the body;
an electrode assembly (16) provided at the tip of the shaft (20);
The electrode assembly (16) includes a plurality of splines (24) each having at least one electrode (26) and a tip member (22) connected to a tip side of the plurality of splines (24);
Each of the plurality of splines (24) is deformable into a sector shape having an arc-shaped region (28) along a common imaginary circle (50) when viewed in the axial direction of the shaft (20);
When each of the plurality of splines (24) is fan-shaped, the plurality of arc-shaped regions (28) formed by the plurality of splines (24) occupy 80% or more of the circumference of the imaginary circle (50) as a whole.
An electrode catheter (10).

According to the electrode catheter (10) of the first item, the multiple arc-shaped regions (28) formed by the multiple splines (24) occupy 80% or more of the circumference of the virtual circle (50) as a whole. Therefore, the multiple splines (24) can be simultaneously brought into contact with most of the circumferential direction of the inner wall of tubular body tissue, such as the boundary between the pulmonary vein and the left atrium. Therefore, the transmission of abnormal electrical signals from the pulmonary vein to the left atrium can be blocked with a single cauterization without changing the position of the multiple splines (24).

[Second item]
When each of the plurality of splines (24) is fan-shaped, at least two adjacent splines (24) of the plurality of splines (24) have overlapping regions (30) that overlap each other when viewed in the axial direction.
Item 1. An electrode catheter (10) as described in item 1.

The electrode catheter (10) according to the second item has at least two adjacent splines (24) arranged so that there is no gap between them when viewed in the axial direction, so that the transmission of abnormal electrical signals from the pulmonary vein to the left atrium can be blocked more reliably.

[Third item]
When each of the multiple splines (24) is fan-shaped, at least a portion of an electrode (26) of one spline (24) and at least a portion of an electrode (26) of the other spline (24) among at least two adjacent splines (24) overlap each other when viewed in the axial direction.
Item 2. An electrode catheter (10) as described in item 2.

According to the electrode catheter (10) of the third item, at least two adjacent splines (24) have at least two electrodes (26) that overlap when viewed in the axial direction, so that cauterization using these electrodes (26) can more reliably block the transmission of abnormal electrical signals from the pulmonary vein to the left atrium.

[4th item]
When each of the plurality of splines (24) is fan-shaped, non-adjacent splines (24) among the plurality of splines (24) do not have an overlapping region (30);
Item 2. An electrode catheter (10) according to item 2 or 3.

In the electrode catheter (10) according to the fourth item, non-adjacent splines (24) do not have overlapping regions (30), so there is no need for the splines (24) to be excessively twisted around the central axis of the shaft (20), making it easier to handle.

[Item 5]
The tip member (22) fixes at least two adjacent splines (24) of the plurality of splines (24) so as to be spaced at a predetermined angle around the central axis of the shaft (20);
The shaft (20) has at least two adjacent splines (24) fixed at positions rotated relative to the tip member (22) by an angle between 1 and 3 times the angular interval around the central axis.
5. An electrode catheter (10) according to any one of claims 1 to 4.

The electrode catheter (10) according to the fifth item can block the transmission of abnormal electrical signals from the pulmonary vein to the left atrium while avoiding the spline (24) from being excessively twisted around the central axis of the shaft (20).

[Item 6]
When each of the plurality of splines (24) is fan-shaped, among the plurality of electrodes (26) of the plurality of splines (24), the plurality of electrodes (26) arranged in the plurality of arc-shaped regions (28) are arranged at equal intervals on the circumference of the imaginary circle (50).
6. An electrode catheter (10) according to any one of claims 1 to 5.

The electrode catheter (10) according to the sixth aspect of the present invention allows the inner circumference of the boundary between the pulmonary vein and the left atrium to be cauterized uniformly at once using multiple electrodes (26) arranged at equal intervals around the circumference of an imaginary circle (50).

[Item 7]
When each of the plurality of splines (24) is fan-shaped, the arcuate region (28) of each spline (24) includes the center of the spline (24) in the axial direction and is located in a region within 90% of the total axial length of the electrode assembly (16);
7. An electrode catheter (10) according to any one of claims 1 to 6.

In the electrode catheter (10) according to the seventh item, the arc-shaped region (28) is located in a region including the axial center where the electrode assembly (16) is most likely to become large in the radial direction perpendicular to the axial direction, making it easier to reliably bring the arc-shaped region (28) into contact with the inner circumference of the tubular body tissue.

[Item 8]
A shaft (20) to be inserted into the body;
an electrode assembly (16) provided at the tip of the shaft (20);
The electrode assembly (16) includes a plurality of splines (24) each having at least one electrode (26) and a tip member (22) connected to a tip side of the plurality of splines (24);
With the multiple splines (24) in contact with the inner wall of the boundary (116) between the pulmonary vein (112) and the left atrium (114), an electrical pulse is applied through the multiple electrodes (26), thereby enabling cauterization so as to simultaneously block the electrical transmission pathway (118) of atrial fibrillation.
An electrode catheter (10).

This disclosure can be used in electrode catheters.

10 electrode catheter, 16 electrode assembly, 20 shaft, 22 tip member, 24 spline, 26 electrode, 28 arc region, 30 overlap region, 50 virtual circle, 112 pulmonary vein, 114 left atrium, 116 boundary portion, 118 transmission path.

Claims (8)

A shaft that is inserted into the body;
an electrode assembly provided at a tip of the shaft;
The electrode assembly includes a plurality of splines each having at least one electrode, and a tip member connected to a tip side of the plurality of splines,
each of the plurality of splines is deformable into a sector shape having an arc-shaped region along a common imaginary circle when viewed in an axial direction of the shaft;
when each of the plurality of splines is in the sector shape, a plurality of arc-shaped regions formed by the plurality of splines occupy 80% or more of a circumference of the virtual circle as a whole;
Electrode catheter. When each of the plurality of splines has the sector shape, at least two adjacent splines among the plurality of splines have overlapping regions that overlap each other when viewed in the axial direction.
10. The electrode catheter of claim 1. when each of the plurality of splines has the sector shape, at least a portion of an electrode of one of the at least two adjacent splines and at least a portion of an electrode of the other spline overlap with each other when viewed from the axial direction;
3. The electrode catheter of claim 2. when each of the plurality of splines has the sector shape, non-adjacent splines among the plurality of splines do not have the overlapping region.
3. The electrode catheter of claim 2. the tip member fixes at least two adjacent splines among the plurality of splines so as to be spaced at a predetermined angle around a central axis of the shaft,
The shaft fixes the at least two adjacent splines at positions rotated relative to the tip member by an angle between 1 and 3 times the angular interval around the central axis.
10. The electrode catheter of claim 1. when each of the plurality of splines is in the sector shape, among the plurality of electrodes of the plurality of splines, the plurality of electrodes arranged in the plurality of arc-shaped regions are arranged at equal intervals on the circumference of the virtual circle.
10. The electrode catheter of claim 1. When each of the plurality of splines is in the sector shape, the arcuate region of each spline includes a center of the spline in the axial direction and is located in a region within 90% of the total axial length of the electrode assembly.
7. An electrode catheter according to any one of claims 1 to 6. A shaft that is inserted into the body;
an electrode assembly provided at a tip of the shaft;
The electrode assembly includes a plurality of splines each having at least one electrode, and a tip member connected to a tip side of the plurality of splines,
When the plurality of splines are in contact with the inner wall of the boundary between the pulmonary vein and the left atrium, an electric pulse is applied through the plurality of electrodes, thereby enabling cauterization so as to block the electrical transmission pathway of atrial fibrillation at once.
Electrode catheter.

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