Electrode catheter

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

[0001] The present disclosure relates to electrode catheters.

[0002] A catheter is a type of medical device inserted into the body for diagnosis or treatment. One known example is an electrode catheter that includes a shaft and a basket electrode assembly coupled to the distal end of the shaft (see, for example, Patent Document 1). The basket electrode assembly includes a plurality of splines. The basket electrode assembly is configured to change shape from a contracted shape to an expanded shape by deforming the splines.

[0003] Special Publication No. 2016-507349

[0004] The electrode catheter described above has difficulty in simultaneously contacting most of the inner circumference of tubular body tissue, so that, for example, when cauterizing the boundary between the pulmonary vein and the left atrium for the treatment of atrial fibrillation, it is necessary to cauterize multiple times while changing the position of the spline.

[0005] The present disclosure has been made in consideration of the above circumstances, and its object is to provide an electrode catheter that can simultaneously contact most of the inner circumference of tubular body tissue.

[0006] One aspect of the present disclosure is an electrode catheter. The electrode catheter includes a shaft to be inserted into a body and an electrode assembly provided at the tip of the shaft. The electrode assembly includes a plurality of splines, each having at least one electrode, and a tip member connected to the tip side of the plurality of splines. When viewed in the axial direction of the shaft, each of the plurality of splines is deformable into a fan shape having an arc-shaped region along a common imaginary circle, 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.

[0007] Another aspect of the present disclosure is an electrode catheter. The electrode catheter includes a shaft to be inserted into the body and an electrode assembly provided at the tip of the shaft. The electrode assembly includes a plurality of splines, each having at least one electrode, and a tip member connected to the 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 electrical pulse is applied through the plurality of electrodes, thereby cauterizing the boundary so as to simultaneously interrupt the electrical transmission pathway of atrial fibrillation.

[0008] Any combination of the above components, and conversion of the expression of the present disclosure into a method, device, system, etc., are also valid aspects of the present disclosure.

[0009] The electrode catheter of the present disclosure is capable of simultaneously contacting a majority of the inner circumference of tubular body tissue.

[0010] Fig. 6 is an explanatory diagram relating to a usage scene of the electrode catheter according to the first embodiment. Fig. 7 is a side view schematically showing the vicinity of the tip of the electrode catheter shown in Fig. 1. Fig. 8 is a view of the electrode catheter shown in Fig. 1 from the tip side in the axial direction of the shaft. Fig. 9 is a view schematically showing the boundary between the pulmonary vein and the left atrium that is cauterized by the electrode catheter shown in Fig. 1. Fig. 10 is a side view schematically showing an example of the overall configuration of the electrode catheter shown in Fig. 1. Fig. 11 is a side view schematically showing the vicinity of the tip of the electrode catheter according to a second embodiment. Fig. 12 is a view of the electrode catheter shown in Fig. 6 from the tip side in the axial direction of the shaft.

[0011] The present disclosure will be described below 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, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are intended to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0012] First Embodiment FIG. 1 is an explanatory diagram illustrating a usage scenario of an electrode catheter 10 according to a first embodiment of the present disclosure. The electrode catheter 10 is used to treat a living body. Here, "treatment" refers to an action related to medical treatment or examination of the living body. The electrode catheter 10 of this embodiment is used to treat atrial fibrillation using PFA (Pulsed Field Ablation). Atrial fibrillation is often caused by the transmission of abnormal electrical signals generated in the pulmonary veins 112 to the left atrium 114. This treatment is typically performed by cauterizing the boundary between the pulmonary veins 112 and the left atrium 114 using the electrode assembly 16 of the electrode catheter 10. Here, the ablation area Sa by the electrode catheter 10 is hatched. This blocks the transmission of abnormal electrical signals from the pulmonary veins 112 to the left atrium 114. The electrode assembly 16 can be used to apply current to a return electrode placed outside the body, a monopolar method, or a bipolar method, which applies current to another electrode placed inside the body. 1 shows a circular ablation area Sa, but the ablation area Sa indicates the approximate area ablated by the electrode catheter 10, and the actual ablation location does not necessarily have to coincide with the ablation area Sa. Details of the ablation area Sa will be described later.

[0013] FIG. 2 is a side view schematically showing the vicinity of the distal end of the electrode catheter 10. The electrode catheter 10 includes a shaft 20 that is inserted into the body and an electrode assembly 16 provided at the distal end of the shaft 20. FIG. 3 is a view of the electrode catheter 10 as viewed from the distal end in the axial direction of the shaft 20. Hereinafter, the side of the electrode catheter 10 that is inserted into the body will be referred to as the "distal end" and the side that is placed outside the body will be referred to as the "proximal end." In addition, for each member constituting the electrode catheter 10, the side that is the same as the distal end of the electrode catheter 10 will be referred to as the "distal end" of that member, and the side that is the same as the proximal end of the electrode catheter 10 will be referred to as the "proximal end" of that member. In this specification, "viewed from the distal end in the axial direction" means viewing the electrode catheter 10 from a viewpoint located distal to the electrode catheter 10 along the axial direction of the shaft 20, toward the proximal end.

[0014] The shaft 20 may be a long, cylindrical 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 forming the shaft 20 may be any flexible and biocompatible material. For example, the shaft 20 may be formed from a known resin such as polyolefin or polyamide elastomer.

[0015] The electrode assembly 16 includes a plurality of splines 24a to 24f and a tip member 22 connected by attachment or the like to the tip sides of the plurality of splines 24a to 24f. Hereinafter, the common description for each of the plurality of splines 24a to 24f will also be simply referred to as spline 24. For other reference numerals with an alphabetical suffix, the common description for those reference numerals will be written without the alphabetical suffix as appropriate.

[0016] 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 linearly 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, like the shaft 20, may be made of a known resin such as polyolefin or polyamide elastomer.

[0017] The electrode catheter 10 according to this embodiment includes six splines 24a to 24f. The splines 24a to 24f are arranged adjacent to each other in the following order in a clockwise direction along the circumferential direction when viewed from the distal end. That is, the splines 24a and 24b, the splines 24b and 24c, the splines 24c and 24d, the splines 24d and 24e, the splines 24e and 24f, and the splines 24f and 24a are adjacent to each other. Furthermore, near the centers 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.

[0018] The base end side of the spline 24 is connected to the shaft 20. As an example, a part of the spline 24 including the base end (hereinafter referred to as the "base end") is inserted into the tip end side of the shaft 20 and bundled. The base end side of the spline 24 and the shaft 20 are joined to each other by a known joining method such as welding or bonding with an adhesive.

[0019] The tip member 22 may cover and bundle a portion of the plurality of splines 24a to 24f, including the tips thereof (hereinafter referred to as "tip portions"). In other words, the tip portions of the plurality of splines 24a to 24f may be covered with the tip member 22. The tip member 22 may have any shape, and is cap-shaped as an example. The tip member 22 may also 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 interior of the tip member 22 may be filled with an adhesive. In this case, the plurality of splines 24a to 24f are likely to be firmly fixed to each other by the adhesive.

[0020] The shape of the splines 24 changes in response to a deformation operation, which will be described later. That is, 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. As will be described in detail later, an example of the contracted shape is a "petal shape." On the other hand, an example of the 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 to the expanded shape.

[0021] 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 circumferential surface of the spline 24. The electrodes 26 of the same spline 24 are arranged spaced apart from one another along the longitudinal direction of the spline 24. In this case, the distance between adjacent electrodes 26 may be constant or may vary. Furthermore, the number of electrodes 26 of each spline 24 may be the same or may vary. In this embodiment, the distance between adjacent electrodes 26 is constant, and all of the electrodes 26 are arranged within a certain region that includes the center of each spline 24 in the longitudinal direction. Each of the multiple splines 24a to 24f according to this embodiment has four electrodes 26.

[0022] 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 equal to the outer diameter of the spline 24, and is, for example, 0.5 mm to 2.0 mm.

[0023] Conductive wires are individually and electrically connected to the electrodes 26. The conductive wires pass from inside the spline 24 through the shaft 20 and the handle 8 (described later) and are connected to an external power supply device via the handle 8.

[0024] As shown in FIG. 3 , when the splines 24a to 24f have an expanded shape, the splines 24a to 24f form a plurality of arc-shaped regions 28a to 28f that follow a common imaginary circle 50 when viewed in the axial direction of the shaft 20. Specifically, the spline 24a forms the arc-shaped region 28a that follows a portion of the imaginary circle 50. Similarly, the splines 24b to 24f each form an arc-shaped region 28b to 28f that follows a portion of the imaginary circle 50. The formation of the arc-shaped regions 28a to 28f by the splines 24a to 24f that follow the common imaginary circle 50 is not limited to when the splines 24a to 24f have an expanded shape. A shape in which each of the splines 24a to 24f has an arc-shaped region 28 that follows the common imaginary circle 50 is also referred to as a fan shape. In other words, each of the multiple splines 24a to 24f can be deformed into a fan 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 substantially coincides with the circumferential direction of the imaginary circle 50 when viewed from the axial direction of the shaft 20.

[0025] In the present embodiment, the center of the imaginary circle 50 is located at the center of the tip member 22 when viewed in the axial direction of the shaft 20. In the present embodiment, the arc-shaped region 28 constitutes a fixed region that includes 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 that extends from the tip member 22 in the radial direction of the imaginary circle 50 and connects to one end of the arc-shaped region 28, and a region that extends from the shaft 20 in the radial direction of the imaginary circle 50 and connects to the other end of the arc-shaped region 28. Furthermore, in the present embodiment, the arc-shaped region 28 constitutes the region of the spline 24 that is farthest from the center of the imaginary circle 50 when viewed in the axial direction of the shaft 20. That is, in the present embodiment, the imaginary circle 50 is an imaginary circle that can be drawn on the outermost periphery of the spline 24 when viewed in the axial direction of the shaft 20.

[0026] When each of the splines 24a-24f is fan-shaped, the arc-shaped regions 28a-28f formed by the splines 24a-24f collectively occupy 80% or more of the circumference of the imaginary circle 50. In other words, the proportion of the entire circumference of the imaginary circle 50 occupied by the arc-shaped regions 28a-28f is 80% or more of the entire circumference of the imaginary circle 50. Therefore, the splines 24a-24f can be simultaneously brought into contact with most of the circumferential area of ​​the inner wall of tubular body tissue, such as the boundary between the pulmonary vein 112 and the left atrium 114 shown in FIG. 1 . Therefore, transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 can be blocked with a single ablation without changing the positions of the splines 24a-24f. In this embodiment, as shown in FIG. 3 , the arc-shaped regions 28a-28f overlap with the imaginary circle 50 over substantially the entire circumference of the imaginary circle 50 as viewed in the axial direction of the shaft 20.

[0027] As shown in FIG. 3 , when each of the plurality of splines 24a to 24f is fan-shaped, at least two adjacent splines of the plurality of splines 24a to 24f, for example, spline 24a and spline 24b, have an overlap region 30 where they overlap when viewed in the axial direction of the shaft 20. Specifically, spline 24a and spline 24b intersect with each other in the overlap region 30 when viewed in the axial direction of the shaft 20. The overlap region 30 is also included in an arc-shaped region 28. Therefore, adjacent splines 24 are arranged without any gaps when viewed in the axial direction of the shaft 20, which more reliably blocks the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114. In this embodiment, not only spline 24a and spline 24b but all adjacent splines 24 have the overlap region 30.

[0028] 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.

[0029] 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 fixes the at least two adjacent splines 24, for example, spline 24a and spline 24b, at a position rotated about the central axis of the shaft 20 relative to the tip member 22 by an angle between one and three times the angular interval α.

[0030] In FIG. 3 , the twist angle β is the clockwise angle at which the spline 24a is fixed to the shaft 20, with the position at which the spline 24a is fixed to the distal end member 22 as the reference. Similarly, the spline 24b is fixed to the shaft 20 at a position rotated clockwise by the twist angle β from the position at which the spline 24b is fixed to the distal end member 22. In this case, the twist angle β is greater than or equal to one time and less than or equal to three times the angle interval α. By setting the twist angle β to be greater than or equal to one time the angle interval α, it becomes easier to form the overlap region 30, which makes it easier to block the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114. By setting the twist angle β to be less than or equal to three times the angle interval α, it becomes possible to prevent the spline 24 from being excessively twisted around the central axis of the shaft 20.

[0031] In this embodiment, the above-described relationship between the angular interval α and the twist angle β is satisfied not only for the splines 24a and 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.

[0032] 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, which are arranged in the arc-shaped regions 28a to 28f, are arranged at equal intervals on the circumference of an 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 in the axial direction of the shaft 20. The electrodes 26 closest to each other on adjacent splines 24 are arranged at substantially the same intervals as the electrodes 26 on each spline 24 as viewed in the axial direction of the shaft 20. In this case, "the electrodes 26 are evenly spaced" means that, in a plane as viewed in the axial direction of the shaft 20 as shown in FIG. 3 , the difference between the interval between any two adjacent electrodes 26 and the average interval between all adjacent electrodes 26 is, for example, less than 10%. When each of the plurality of splines 24 a to 24 f is fan-shaped, each of the plurality of splines 24 a to 24 f may have one or more electrodes 26 arranged in a region other than the arc-shaped region 28 .

[0033] When each of the plurality of splines 24a to 24f is fan-shaped, the plurality of electrodes 26 of the plurality of splines 24a to 24f may be disposed at positions corresponding to a plurality of imaginary points that are equally spaced on the circumference of an imaginary circle 50, as viewed in the axial direction of the shaft 20. In this case, "the electrodes 26 are 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.

[0034] As shown in FIG. 2 , when each of the multiple splines 24 a to 24 f is fan-shaped, the arcuate region 28 of each spline 24 is located in a region including the center of the spline 24 in the axial direction. The arcuate region 28 of each spline 24 is located in a region 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. Because the arcuate region 28 is located in such a region, it is easy to ensure that the arcuate region 28 comes into reliable 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 .

[0035] As described above, the electrode catheter 10 according to the first embodiment has been described as including six splines 24a to 24f. However, the number of splines 24 included in the electrode catheter 10 is not limited to six, and may be four or more.

[0036] 4 is a schematic diagram showing a boundary 116 between a pulmonary vein 112 and the left atrium 114 that is ablated by the electrode catheter 10. When treating atrial fibrillation, the electrode catheter 10 advances from inside the left atrium 114 to the boundary 116 with the distal end of the electrode catheter 10 directed toward 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. When an electrical pulse is applied through the multiple electrodes 26 in this state, the boundary 116 is ablated at multiple ablation sites 130. The multiple ablation sites 130 are included in the ablation range Sa also shown in FIG. 1 .

[0037] The ablation sites 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 primarily the arc-shaped regions 28. That is, the ablation sites 130 are formed to correspond to the shapes and arrangements of the arc-shaped regions 28. An abnormal electrical signal transmission pathway 118 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 a myocardial sleeve formed at the boundary 116, as shown in FIG. 4 . Therefore, the ablation sites 130 formed to correspond to the shapes and arrangements of the arc-shaped regions 28 can block the abnormal electrical signal transmission pathway 118.

[0038] In this way, by using the electrode catheter 10 of this embodiment, electrical pulses can be applied through the multiple electrodes 26 while the multiple splines 24a to 24f are in contact with the inner wall of the boundary 116 between the pulmonary vein 112 and the left atrium 114, thereby cauterizing the electrical transmission pathway 118 of atrial fibrillation so as to block it all at once.

[0039] Figure 5 is a side view showing a schematic example of the overall configuration of the electrode catheter 10. As shown in Figure 5, the electrode catheter 10 may include a handle 8 connected to the proximal end 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 proximal end of the shaft 20, a rotation operation unit 12, and a slide member 13.

[0040] The handle body 11 corresponds to the part that the operator actually grips. The handle body 11 may have any shape. For 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.

[0041] The rotation operation unit 12 is a part that is operated by a rotation operation or 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 main body 11. The tips of the pair of pull wires pass from the handle main 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 is bent or flexed.

[0042] The slide member 13 is a part that is subjected to a deformation operation, such as a sliding operation, by an operator when the shape of the plurality of splines 24 is changed between the undeployed or contracted shape and the expanded or expanded shape. The slide member 13 is slidable along the central axis of the shaft 20 in the handle body 11.

[0043] 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 main body 11 through the shaft 20 and is fixed inside the tip member 22. The slide member 13 is movable to any position along the central axis of the shaft 20 in the handle main body 11. Therefore, depending on the position of the slide member 13, the shape of the multiple splines 24 can be changed to the undeployed shape or contracted shape, the deployed shape or expanded shape, or any intermediate shape between the undeployed shape and the deployed shape.

[0044] The deformation member 14 may have any shape, structure, or material as long as it is long. As an example, the deformation member 14 is a wire.

[0045] [Second Embodiment] A second embodiment of the present disclosure will be described with reference to Figures 6 and 7. In the following embodiments, the same content as in the first embodiment may be applied to components described in the first embodiment but not described below. Figure 6 is a side view schematically showing the vicinity of the tip of an 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.

[0046] The electrode catheter 10A of this embodiment differs from the electrode catheter 10 of the first embodiment in the arrangement of the multiple electrodes 26 on each of the multiple splines 24a to 24f. That is, when each of the multiple splines 24a to 24f is fan-shaped, at least a portion of the electrode 26 on 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 on the other spline 24, as viewed in the axial direction of the shaft 20. Specifically, as shown in FIG. 7 , the electrode 261 on the spline 24a and the electrode 262 on the spline 24b overlap with each other as viewed in the axial direction of the shaft 20. This makes it possible to more reliably block the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 by cauterizing using these electrodes 26.

[0047] In this embodiment, of the electrodes 26 of the spline 24a, the electrode 261 located closest to the spline 24b and the electrode 262 located closest to the spline 24a overlap each other when viewed in the axial direction of the shaft 20. With this configuration, the number of overlapping electrodes 26 can be minimized while still achieving the effect of blocking the transmission of abnormal electrical signals.

[0048] 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 arranged at equal intervals on the circumference of an imaginary 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 imaginary circle 50 when viewed in the axial direction of the shaft 20.

[0049] The embodiments of the present disclosure have been described in detail above. The above-described embodiments merely illustrate specific examples of implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design modifications, such as changing, adding, or deleting components, are possible within the scope of the concept of the present disclosure defined in the claims. A new embodiment with design modifications will combine the effects of the combined embodiments and modifications. In the above-described embodiments, content that allows such design modifications is emphasized by using notations such as "in this embodiment" or "in this embodiment," but design modifications are also permitted even in content without such notation. Any combination of components included in each embodiment is also valid as an aspect of the present disclosure. Hatching on cross sections in the drawings does not limit the material of the hatched object.

[0050] The embodiments may be specified by the following items.

[0051] [Item 1] An electrode catheter (10) comprising: a shaft (20) to be inserted into a body; and an electrode assembly (16) provided at the tip of the shaft (20), wherein the electrode assembly (16) comprises a plurality of splines (24) each having at least one electrode (26), and a tip member (22) connected to the tip sides of the plurality of splines (24), wherein each of the plurality of splines (24) is deformable into a fan shape having an arc-shaped region (28) that follows a common imaginary circle (50) when viewed in the axial direction of the shaft (20), and wherein 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) collectively occupy 80% or more of the circumference of the imaginary circle (50).

[0052] According to the electrode catheter (10) of the first aspect, the plurality of arc-shaped regions (28) formed by the plurality of splines (24) collectively occupy 80% or more of the circumference of the imaginary circle (50). Therefore, the plurality of splines (24) can simultaneously contact the majority of the circumferential area of ​​the inner wall of tubular body tissue, such as the boundary between the pulmonary vein and the left atrium. Therefore, transmission of abnormal electrical signals from the pulmonary vein to the left atrium can be blocked with a single ablation without changing the positions of the plurality of splines (24).

[0053] [Item 2] The electrode catheter (10) according to Item 1, wherein 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.

[0054] According to the electrode catheter (10) relating to the second item, at least two adjacent splines (24) are arranged without any gaps when viewed from the axial direction, so that the transmission of abnormal electrical signals from the pulmonary vein to the left atrium can be more reliably blocked.

[0055] [Item 3] The electrode catheter (10) according to Item 2, wherein when each of the plurality of splines (24) is fan-shaped, at least a portion of the electrode (26) of one of at least two adjacent splines (24) overlaps with at least a portion of the electrode (26) of the other spline (24) when viewed in the axial direction.

[0056] According to the electrode catheter (10) relating to the third item, at least two adjacent splines (24) have at least two electrodes (26) that overlap when viewed in the axial direction, and by cauterizing using these electrodes (26), it is possible to more reliably block the transmission of abnormal electrical signals from the pulmonary veins to the left atrium.

[0057] [Item 4] The electrode catheter (10) according to item 2 or 3, wherein 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).

[0058] According to the electrode catheter (10) relating 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.

[0059] [Item 5] An electrode catheter (10) according to any one of Items 1 to 4, wherein the tip member (22) fixes at least two adjacent splines (24) of the plurality of splines (24) so ​​that they are spaced at a predetermined angular interval around the central axis of the shaft (20), and the shaft (20) fixes at least two adjacent splines (24) at positions rotated relative to the tip member (22) around the central axis by an angle between one and three times the angular interval.

[0060] 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).

[0061] [Item 6] The electrode catheter (10) according to any one of Items 1 to 5, wherein when each of the plurality of splines (24) is fan-shaped, among the plurality of electrodes (26) carried by 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).

[0062] According to the electrode catheter (10) relating to the sixth item, the inner circumference of the boundary between the pulmonary vein and the left atrium can be uniformly cauterized at once by a plurality of electrodes (26) arranged at equal intervals on the circumference of the imaginary circle (50).

[0063] [Item 7] The electrode catheter (10) according to any one of Items 1 to 6, wherein when each of the plurality of splines (24) is fan-shaped, the arc-shaped 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).

[0064] According to the electrode catheter (10) of the seventh item, the arc-shaped region (28) is located in a region including the axial center where the electrode assembly (16) is likely to become largest 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 tubular body tissue.

[0065] [Item 8] An electrode catheter (10) comprising: a shaft (20) to be inserted into the body; and an electrode assembly (16) provided at the tip of the shaft (20), wherein the electrode assembly (16) comprises a plurality of splines (24) each having at least one electrode (26), and a tip member (22) connected to the tip side of the plurality of splines (24), and wherein an electrical pulse is applied through the plurality of electrodes (26) while the plurality of splines (24) are in contact with the inner wall of the boundary (116) between the pulmonary vein (112) and the left atrium (114), thereby cauterizing the electrical transmission pathway (118) of atrial fibrillation so as to block it all at once.

[0066] The present disclosure may be utilized in electrode catheters.

[0067] 10 Electrode catheter, 16 Electrode assembly, 20 Shaft, 22 Tip member, 24 Spline, 26 Electrode, 28 Arc-shaped region, 30 Overlapping region, 50 Virtual circle, 112 Pulmonary vein, 114 Left atrium, 116 Boundary, 118 Conduction pathway.

Claims

1. An electrode catheter comprising: a shaft to be inserted into the body; and an electrode assembly provided at the tip of the shaft, the electrode assembly comprising a plurality of splines, each having at least one electrode, and a tip member connected to the tip sides of the plurality of splines, each of the plurality of splines being deformable into a sector 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 in the sector shape, the plurality of arc-shaped regions formed by the plurality of splines occupy 80% or more of the circumference of the imaginary circle as a whole.

2. The electrode catheter according to claim 1, wherein when each of said plurality of splines is in said sector shape, at least two adjacent splines of said plurality of splines have an overlapping region that overlaps with each other when viewed in said axial direction.

3. The electrode catheter according to claim 2, wherein when each of said plurality of splines is in said sector shape, of said at least two adjacent splines, at least a portion of the electrode on one spline and at least a portion of the electrode on the other spline overlap each other when viewed in the axial direction.

4. The electrode catheter according to claim 2, wherein when each of said plurality of splines is in said sector shape, non-adjacent splines among said plurality of splines do not have said overlapping region.

5. The electrode catheter according to claim 1, wherein said tip member fixes at least two adjacent splines of said plurality of splines so that they are spaced at a predetermined angular interval around the central axis of said shaft, and said shaft fixes said at least two adjacent splines at positions rotated relative to said tip member by an angle between 1 and 3 times said angular interval around said central axis.

6. The electrode catheter according to claim 1, wherein, when each of said plurality of splines is in the shape of a sector, among the plurality of electrodes possessed by said plurality of splines, the plurality of electrodes arranged in said plurality of arc-shaped regions are arranged at equal intervals on the circumference of said imaginary circle.

7. An electrode catheter according to any one of claims 1 to 6, wherein when each of the plurality of splines is in the sector shape, the arc-shaped region of each spline includes the 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.

8. An electrode catheter comprising: a shaft to be inserted into the body; and an electrode assembly provided at the tip of the shaft, the electrode assembly comprising a plurality of splines, each having at least one electrode, and a tip member connected to the tip sides of the plurality of splines, wherein an electrical pulse is applied through the plurality of electrodes with the plurality of splines in contact with the inner wall of the boundary between the pulmonary vein and the left atrium, thereby cauterizing the electrical transmission pathway of atrial fibrillation so as to cut off the pathway all at once.

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