Electrode catheter

Abstract

To provide an electrode catheter which can come into contact with most parts of an inner periphery of a tubular biological tissue simultaneously.SOLUTION: An electrode catheter include: a shaft inserted into a body; and an electrode assembly 16 provided an a tip end of the shaft. The electrode assembly 16 includes: a plurality of splines 24a-24f each having at least one electrode 26; and a tip end member connected to the tip end sides of the plurality of splines 24a-24f. Each of the plurality of splines 24a-24f is deformable in a fan shape having arc regions 28a-28f along a common virtual circle 50 when viewed from a shaft axis direction. When each of the plurality of splines 24a-24f is in a fan shape, the plurality of arc regions 28a-28b formed of the plurality of splines 24a-24f account for 80% or more of a circumference of the virtual circle 50 as a whole.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an electrode catheter.

Background Art

[0002] A catheter is a type of medical device inserted into the body for diagnosis or treatment. As an example, an electrode catheter including a shaft and a basket electrode assembly coupled to the tip of the shaft is known (see, for example, Patent Document 1). Here, the basket electrode assembly includes a plurality of splines. And by deforming the splines, the basket electrode assembly is configured to deform from a contracted shape to an expanded shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It has been difficult for the above-described electrode catheter to simultaneously contact most of the inner circumference of a tubular body tissue. Therefore, for example, when ablating the boundary between the pulmonary vein and the left atrium for the treatment of atrial fibrillation, it has been necessary to perform ablation multiple times while changing the position of the spline.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide an electrode catheter capable of simultaneously contacting most of the inner circumference of a tubular body tissue.

Means for Solving the Problems

[0006] One aspect of the present disclosure is an electrode catheter. The electrode catheter includes a shaft that is 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. Each of the plurality of splines is deformable into a fan shape having an arc-shaped region along a common virtual circle when viewed from the axial direction of the shaft, and when each of the plurality of splines is in a fan shape, the plurality of arc-shaped regions formed by the plurality of splines occupy more than 80% of the circumference of the virtual circle as a whole.

[0007] Another aspect of the present disclosure is an electrode catheter. The electrode catheter includes a shaft that is 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 can be applied through the plurality of electrodes to ablate the electrical transmission path of atrial fibrillation at once.

[0008] Any combination of the above components, and those obtained by converting the expressions of the present disclosure among methods, apparatuses, systems, etc., are also effective as aspects of the present disclosure.

Advantages of the Invention

[0009] The electrode catheter of the present disclosure can be simultaneously brought into contact with most of the inner circumference of the tubular body tissue.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0011] Hereinafter, the present disclosure will be described with reference to the drawings based on preferred embodiments. The embodiments are illustrative and not restrictive of 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 are denoted by the same reference numerals, and repeated explanations are omitted as appropriate. Also, the scales and shapes of the respective parts shown in each figure are set for convenience in order to facilitate the explanation, and are not to be construed restrictively unless otherwise specified. Further, when terms such as "first", "second", etc. are used in this specification or claims, these terms do not represent any order or importance unless otherwise specified, and are used to distinguish one configuration from another. Also, in each drawing, some members that are not important in explaining the embodiment are omitted from the display.

[0012] [First Embodiment] FIG. 1 is an explanatory diagram regarding a usage scenario of the electrode catheter 10 according to the first embodiment of the present disclosure. The electrode catheter 10 is used for treating a living body. Here, the "treatment" refers to an act related to the treatment or examination of a living body. The electrode catheter 10 of the present embodiment is used for treating atrial fibrillation by PFA (Pulsed Field Ablation). Atrial fibrillation often occurs due to 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, hatching is applied to the ablation range Sa by the electrode catheter 10. Thereby, the transmission of abnormal electrical signals from the pulmonary vein 112 to the left atrium 114 is blocked. As the energization method using the electrode assembly 16, in addition to the monopolar method of energizing with a counter electrode plate arranged outside the body, a bipolar method of energizing with other electrodes arranged inside the body can be adopted. In FIG. 1, an annular ablation range Sa is shown, but the ablation range Sa indicates the approximate range to be ablated by the electrode catheter 10, and the actually ablated location does not necessarily coincide with the ablation range Sa. Details of the ablation range Sa will be described later.

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

[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 constituting the shaft 20 may be any material having flexibility and biocompatibility. For example, the shaft 20 is composed of 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 side of the plurality of splines 24a to 24f. Hereinafter, for the common description of each of the plurality of splines 24a to 24f, it will also be simply described as the spline 24. For other reference numerals with an alphabet added at the end, for the common description of those reference numerals, it will be described without adding the alphabet as appropriate.

[0016] The spline 24 is a member connecting between the shaft 20 and the tip member 22. The spline 24 may be a cylindrical member similar to the shaft 20. The length when the spline 24 is stretched 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 constituting the spline 24 may be any material having flexibility and biocompatibility. For example, the spline 24 is composed of a known resin such as polyolefin or polyamide elastomer, similar to the shaft 20.

[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 this order clockwise along the circumferential direction as 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, spline 24f and spline 24a are adjacent to each other respectively. Also, in the vicinity of the center of the spline 24 in the axial direction of the shaft 20, each spline 24 is arranged spaced apart from each other in a plane orthogonal to the central axis of the shaft 20.

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

[0019] The tip member 22 may cover and bundle a part (hereinafter referred to as the "tip portion") including the tip of each of the plurality of splines 24a to 24f. In other words, the tip member 22 may cover the tip portions of the plurality of splines 24a to 24f. The tip member 22 may have any shape, but is, for example, cap-shaped. Also, the tip member 22 may be made of any material, but is, for example, composed of a known resin such as polyamide, polyamide elastomer, polycarbonate, or a known metal such as stainless steel. The inside 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 by the adhesive respectively.

[0020] The spline 24 changes its shape according to a deformation operation described later. That is, the spline 24 is configured to be deformable. Specifically, the shape of each spline 24 changes between an undeveloped shape or a contracted shape in which each spline 24 is not developed along the central axis of the shaft 20 and a developed shape or an expanded shape in which each spline 24 is developed along the central axis of the shaft 20 from the contracted shape. Although details will be described 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 each spline 24 is developed along the central axis of the shaft 20 from the petal shape. FIGS. 2 and 3 both show a state in which each spline 24 is deformed into an expanded shape.

[0021] The plurality of splines 24a to 24f each have 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. Each electrode 26 of the same spline 24 is arranged at intervals from each other along the longitudinal direction of the spline 24. In this case, the intervals between adjacent electrodes 26 may be constant or different. Also, the number of electrodes 26 of each spline 24 may be the same or different. In the present embodiment, the intervals between adjacent electrodes 26 are constant, and all the electrodes 26 are arranged within a certain region including the center in the longitudinal direction of each spline 24. The plurality of splines 24a to 24f according to the present embodiment each have four electrodes 26.

[0022] The electrode 26 is made of a material having conductivity. For example, the electrode 26 is made of a metal having good electrical conductivity such as aluminum (Al), copper (Cu), stainless steel, gold (Au), platinum (Pt), etc. 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, for example, 0.5 mm to 2.0 mm.

[0023] Wires are individually and electrically connected to the electrode 26. Further, the wires pass from within the spline 24, through the shaft 20 and into the handle 8 described later, and are connected via the handle 8 to an external power supply device.

[0024] As shown in FIG. 3, when the plurality of splines 24a to 24f are in the expanded shape, when viewed from the axial direction of the shaft 20, the plurality of splines 24a to 24f form a plurality of arc-shaped regions 28a to 28f along a common virtual circle 50. Specifically, the spline 24a forms an arc-shaped region 28a along a part of the virtual circle 50. Similarly, the plurality of splines 24b to 24f each form an arc-shaped region 28b to 28f along a part of the virtual circle 50. The fact that the plurality of splines 24a to 24f form a plurality of arc-shaped regions 28a to 28f along the common virtual circle 50 is not limited to when the plurality of splines 24a to 24f are in the expanded shape. The shape when each of the plurality of splines 24a to 24f has an arc-shaped region 28 along the common virtual circle 50 is also referred to as a fan shape. In other words, each of the plurality of splines 24a to 24f can be deformed into a fan shape having an arc-shaped region 28 along the common virtual circle 50 when viewed from the axial direction of the shaft 20. Here, the fact that the arc-shaped region 28 is along the virtual circle 50 when viewed from the axial direction of the shaft 20 means that the arc-shaped region 28 overlaps the virtual circle 50 when viewed from the axial direction of the shaft 20, and the longitudinal direction of the spline 24 substantially coincides with the circumferential direction of the virtual circle 50 in the arc-shaped region 28 when viewed from the axial direction of the shaft 20.

[0025] 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 in the longitudinal direction of the spline 24. Specifically, when the spline 24 is fan-shaped, the spline 24 includes the arc-shaped region 28, a region extending radially from the tip member 22 to the virtual circle 50 and connected to one end of the arc-shaped region 28, and a region extending radially from the shaft 20 to the virtual circle 50 and connected to the other end of the arc-shaped region 28. Further, in this embodiment, the arc-shaped region 28 constitutes the region of the spline 24 that is 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 peripheral portion of the spline 24 when viewed from the axial direction of the shaft 20.

[0026] When each of the plurality of splines 24a to 24f is fan-shaped, the plurality of arc-shaped regions 28a to 28f formed by the plurality of splines 24a to 24f occupy more than 80% of the circumference of the virtual circle 50 as a whole. That is, the ratio of the whole of the plurality of arc-shaped regions 28a to 28f in the circumference of the virtual circle 50 is more than 80% of the entire circumference of the virtual circle 50. Therefore, the plurality of splines 24a to 24f can be simultaneously brought into contact with most of the circumferential direction of the inner wall of a tubular body tissue such as the boundary between the pulmonary vein 112 and the left atrium 114 shown in FIG. 1. Thus, even without changing the positions of the plurality of splines 24a to 24f, abnormal electrical signal transmission from the pulmonary vein 112 to the left atrium 114 can be blocked by a single ablation. In this embodiment, as shown in FIG. 3, the plurality of arc-shaped regions 28a to 28f overlap the virtual circle 50 in substantially the entire circumference of the virtual circle 50 when viewed from 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 among the plurality of splines 24a to 24f, for example, spline 24a and spline 24b, have an overlapping region 30 that overlaps with each other when viewed from the axial direction of the shaft 20. Specifically, spline 24a and spline 24b intersect with each other in the overlapping region 30 when viewed from the axial direction of the shaft 20. Further, the overlapping region 30 is included in the arc-shaped region 28. Therefore, since adjacent splines 24 are arranged without a gap when viewed from the axial direction of the shaft 20, abnormal electrical signals can be more reliably blocked from being transmitted from the pulmonary vein 112 to the left atrium 114. In the present embodiment, not only spline 24a and spline 24b, but all adjacent splines 24 have the overlapping region 30.

[0028] In the present embodiment, when each of the plurality of splines 24a to 24f is fan-shaped, only adjacent splines 24 have a common overlapping region 30 that overlaps with each other when viewed from the axial direction of the shaft 20. That is, non-adjacent splines 24 do not overlap with each other when viewed from the axial direction of the shaft 20 and do not have the overlapping region 30. Therefore, it is not necessary for the spline 24 to have a shape that is excessively twisted around the central axis of the shaft 20.

[0029] As shown in FIG. 3, the tip member 22 fixes at least two adjacent splines 24 among the plurality of splines 24, for example, spline 24a and spline 24b, at a predetermined angular interval α around the central axis of the shaft 20. Further, the shaft 20 fixes the at least two adjacent splines 24, for example, spline 24a and spline 24b, at a position rotated by an angle of 1 time or more and 3 times or less of the angular interval α with respect to the tip member 22 around the central axis of the shaft 20.

[0030] In FIG. 3, with reference to the position where the spline 24a is fixed to the tip member 22, the clockwise angle at the position where the spline 24a is fixed to the shaft 20 is shown as the twist angle β. Similarly, the spline 24b is fixed to the shaft 20 at a position rotated clockwise by the twist angle β with respect to the position fixed to the tip member 22. At this time, the twist angle β is not less than 1 times and not more than 3 times the angular interval α. By setting the twist angle β to be not less than 1 times the angular interval α, it becomes easier to form the overlapping region 30, and thus it becomes 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 not more than 3 times the angular interval α, it is possible to avoid the spline 24 having a shape that is excessively twisted around the central axis of the shaft 20.

[0031] In this embodiment, not limited to the splines 24a and 24b, all adjacent splines 24 satisfy the relationship between the above-described angular interval α and the twist angle β. In this case, since there are six splines 24a to 24f in this embodiment, the angular interval α may be about 60°. Also, the twist angle β may be not less than about 60° and not more than about 180°.

[0032] As shown in FIG. 3, when each of the plurality of splines 24a to 24f is fan-shaped, among the plurality of electrodes 26 of the plurality of splines 24a to 24f, the plurality of electrodes 26 arranged in the plurality of arc-shaped regions 28a to 28f are arranged at equal intervals on the circumference of the virtual circle 50. Specifically, each of the plurality of splines 24a to 24f has four electrodes 26, and these electrodes 26 are arranged at equal intervals when viewed from the axial direction of the shaft 20 along the longitudinal direction of each spline 24. And, the electrodes 26 that are closest to each other between adjacent splines 24 are arranged at substantially the same interval as between the electrodes 26 of each spline 24 when viewed from the axial direction of the shaft 20. In this case, the plurality of electrodes 26 being at equal intervals means that, in the plane viewed from 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 value of the intervals between all adjacent electrodes 26 is, for example, less than 10%. When each of the plurality of splines 24a to 24f is fan-shaped, each of the plurality of splines 24a to 24f 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 arranged at positions corresponding to a plurality of virtual points that are equally spaced on the circumference of the virtual circle 50 when viewed from the axial direction of the shaft 20. In this case, the electrode 26 being arranged at a position corresponding to the virtual point means that at least a part of the electrode 26 is arranged at a position overlapping the virtual point when viewed from the axial direction of the shaft 20.

[0034] As shown in FIG. 2, when each of the plurality of splines 24a to 24f is fan-shaped, the arc-shaped region 28 of each spline 24 is located in a region including the center of the spline 24 in the axial direction. The arc-shaped region 28 of each spline 24 is located in a region within 90% of the total axial length of the electrode assembly 16, preferably within 80%. Each spline 24 is most likely to be the 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 ensure contact with the inner circumference of a 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] FIG. 4 is a diagram schematically showing the boundary 116 between the pulmonary vein 112 and the left atrium 114 that is cauterized by the electrode catheter 10. During the treatment of atrial fibrillation, the electrode catheter 10 enters the boundary 116 from the inside of the left atrium 114 with the tip side of the electrode catheter 10 facing the pulmonary vein 112. At this time, each of the plurality of splines 24a to 24f is deformed into a fan shape, and the plurality of splines 24a to 24f are brought into contact with the inner wall of the boundary 116. In this state, when an electric pulse is applied through the plurality of electrodes 26, the boundary 116 is cauterized at a plurality of cauterized points 130. The plurality of cauterized points 130 are included in the cauterized range Sa also shown in FIG. 1.

[0037] The plurality of ablation sites 130 respectively correspond to the locations where the plurality of splines 24a to 24f contact the boundary portion 116. The locations where the plurality of splines 24a to 24f contact the boundary portion 116 are mainly the plurality of arc-shaped regions 28. That is, the plurality of ablation sites 130 are formed corresponding to the respective shapes and arrangements of the plurality of arc-shaped regions 28. The abnormal electrical signal transmission path 118 from the pulmonary vein 112 to the left atrium 114 associated with atrial fibrillation is likely to be a path that goes straight from the pulmonary vein 112 to the left atrium 114 as shown in FIG. 4 along a myocardial sleeve or the like formed at the boundary portion 116. Therefore, the plurality of ablation sites 130 formed corresponding to the respective shapes and arrangements of the plurality of arc-shaped regions 28 can block the abnormal electrical signal transmission path 118.

[0038] Thus, by using the electrode catheter 10 of the present embodiment, with the plurality of splines 24a to 24f in contact with the inner wall of the boundary portion 116 between the pulmonary vein 112 and the left atrium 114, an electric pulse is applied through the plurality of electrodes 26, so that ablation can be performed to block the electrical transmission path 118 of atrial fibrillation at once.

[0039] FIG. 5 is a side view schematically showing an 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 proximal end side of the shaft 20. The handle 8 is a portion that an operator such as a doctor grasps or holds when using the electrode catheter 10. The handle 8 may have a handle body 11 mounted on the proximal end side of the shaft 20, a rotation operation portion 12, and a slide member 13.

[0040] The handle body 11 corresponds to the portion that the operator actually holds. The handle body 11 may have any shape. As an example, the handle body 11 has a shape extending along the central axis of the shaft 20. Also, the handle body 11 is made of a known resin such as polycarbonate, polyacetal, or ABS, for example.

[0041] The rotation operation unit 12 is a part where operations such as rotation operation are performed when bending or deflecting the vicinity of the tip of the shaft 20 in both directions. At the rotation operation unit 12, the base ends of a pair of pull wires are fixed within the handle body 11. The tips of the pair of pull wires pass through the inside of the shaft 20 from within the handle body 11 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 side, and the tip side of the shaft 20 to which the tips of the pull wires are fixed bends or deflects.

[0042] The slide member 13 is a part where deformation operations such as slide operation are performed by the operator when deforming the shape of the plurality of splines 24 between the above-described undeveloped shape or contracted shape and the developed shape or expanded shape. The slide member 13 is slidable along the central axis of the shaft 20 in the handle body 11.

[0043] At the slide member 13, the base end of the deformation member 14 is fixed. The tip of the deformation member 14 passes through the inside of the shaft 20 from within the handle body 11 and is fixed within the tip member 22. And the slide member 13 is movable to an arbitrary 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 plurality of splines 24 can be deformed into the above-described undeveloped shape or contracted shape, developed shape or expanded shape, or any intermediate shape between the undeveloped shape and the developed shape.

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

[0045] [Second Embodiment] Referring to FIGS. 6 and 7, a second embodiment of the present disclosure will be described. In the following embodiments, among the components described in the first embodiment, the components not described below may have the same content as that of the first embodiment applied thereto. FIG. 6 is a side view schematically showing the vicinity of the tip of the electrode catheter 10A according to the second embodiment. FIG. 7 is a view of the electrode catheter 10A as seen from the tip side in the axial direction of the shaft 20.

[0046] In the electrode catheter 10A of the present embodiment, the arrangement of the plurality of electrodes 26 respectively provided on the plurality of splines 24a to 24f is different from that of the electrode catheter 10 of the first embodiment. That is, when each of the plurality of splines 24a to 24f is fan-shaped, at least a part of the electrodes 26 provided on one of at least two adjacent splines 24, for example, spline 24a and spline 24b, and at least a part of the electrodes 26 provided on the other spline 24 overlap each other when viewed from the axial direction of the shaft 20. Specifically, as shown in FIG. 7, the electrode 261 provided on the spline 24a and the electrode 262 provided on the spline 24b overlap each other when viewed from the axial direction of the shaft 20. Thereby, by performing ablation 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.

[0047] In the present embodiment, the electrode 261 located on the most spline 24b side among the electrodes 26 provided on the spline 24a and the electrode 262 located on the most spline 24a side among the electrodes 26 provided on the spline 24b overlap each other when viewed from the axial direction of the shaft 20. By adopting such a configuration, it is possible to minimize the number of overlapping electrodes 26 while exerting the effect of blocking the transmission of abnormal electrical signals.

[0048] In the present embodiment, when each of the plurality of splines 24a to 24f is fan-shaped, the plurality of electrodes 26 included in the plurality of splines 24a to 24f may not be arranged at equal intervals on the circumference of the virtual circle 50 as viewed from the axial direction of the shaft 20. However, if the overlapping electrodes 26 of adjacent splines 24 are regarded as one electrode 26, it is also possible to arrange each electrode 26 at equal intervals on the circumference of the virtual circle 50 as viewed from the axial direction of the shaft 20.

[0049] As described above, the embodiments of the present disclosure have been described in detail. The above-described embodiments are merely specific examples for implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design changes such as changes, additions, deletions, etc. of components are possible without departing from the idea of the present disclosure defined in the claims. The new embodiments to which design changes are applied have the effects of the combined embodiments and modifications respectively. In the above-described embodiments, with respect to the content in which such design changes are possible, notations such as "in the present embodiment" and "in the present embodiment" are attached and emphasized, but design changes are also allowed for the content without such notations. Any combination of the components included in each embodiment is also effective as an aspect of the present disclosure. The hatching attached to the cross-section of the drawing does not limit the material of the object to which the hatching is attached.

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

[0051] [Item 1] A shaft (20) inserted into the body, and An electrode assembly (16) provided at the tip of the shaft (20), and The electrode assembly (16) includes 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 Each of the plurality of splines (24) is deformable into a fan shape having an arc-shaped region (28) along a common virtual circle (50) as viewed from the axial direction of the shaft (20), and 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 virtual circle (50) as a whole. Electrode catheter (10).

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

[0053] [Second aspect] When each of the plurality of splines (24) is fan-shaped, at least two adjacent splines (24) among the plurality of splines (24) have an overlapping region (30) that overlaps with each other when viewed axially. The electrode catheter (10) according to the first aspect.

[0054] According to the electrode catheter (10) according to the second aspect, since at least two adjacent splines (24) are arranged without a gap when viewed axially, abnormal electrical signal transmission from the pulmonary vein to the left atrium can be more reliably blocked.

[0055] [Third aspect] When each of the plurality of splines (24) is fan-shaped, at least a part of the electrodes (26) of one spline (24) and at least a part of the electrodes (26) of the other adjacent spline (24) overlap with each other when viewed axially. The electrode catheter (10) according to the second aspect.

[0056] According to the electrode catheter (10) according to Item 3, since at least two adjacent splines (24) have at least two electrodes (26) that overlap when viewed axially, by using these electrodes (26) for ablation, it is possible to more reliably block the transmission of abnormal electrical signals from the pulmonary vein to the left atrium.

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

[0058] According to the electrode catheter (10) according to Item 4, since non-adjacent splines (24) do not have an overlapping region (30), it is not necessary for the spline (24) to have a shape that is excessively twisted around the central axis of the shaft (20), and it can be made easier to handle.

[0059] [Item 5] The distal end member (22) fixes at least two adjacent splines (24) among the plurality of splines (24) at predetermined angular intervals around the central axis of the shaft (20). The shaft (20) fixes at least two adjacent splines (24) at positions rotated by an angle that is 1 time or more and 3 times or less the angular interval around the central axis with respect to the distal end member (22). The electrode catheter (10) according to any one of Items 1 to 4.

[0060] According to the electrode catheter (10) according to Item 5, it is possible to avoid the spline (24) having a shape that is excessively twisted around the central axis of the shaft (20) while blocking the transmission of abnormal electrical signals from the pulmonary vein to the left atrium.

[0061] [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 virtual circle (50). The electrode catheter (10) according to any one of Items 1 to 5.

[0062] According to the electrode catheter (10) according to Item 6, the inner circumference of the boundary between the pulmonary vein and the left atrium can be evenly ablated at once by the plurality of electrodes (26) arranged at equal intervals on the circumference of the virtual circle (50).

[0063] [Item 7] 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). The electrode catheter (10) according to any one of Items 1 to 6.

[0064] According to the electrode catheter (10) according to Item 7, since the arc-shaped region (28) is located in a region including the axial center where the electrode assembly (16) is most likely to be the largest in the radial direction orthogonal to the axial direction, the arc-shaped region (28) can be reliably brought into contact with the inner circumference of the tubular body tissue.

[0065] [Item 8] A shaft (20) inserted into the body, An electrode assembly (16) provided at the tip of the shaft (20), and The electrode assembly (16) includes 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). A plurality of splines (24) are in contact with the inner wall of the boundary portion (116) between the pulmonary vein (112) and the left atrium (114), and an electrical pulse is applied through a plurality of electrodes (26) so that the electrical transmission path (118) of atrial fibrillation can be cauterized to block it all at once. Electrode catheter (10).

Description of reference numerals

[0066] 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 portion, 118 Transmission path.

Claims

1. A shaft to be inserted into the body, and an electrode assembly provided at the tip of the shaft, and 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, each of the plurality of splines is deformable into a fan shape having an arc-shaped region along a common virtual circle when viewed from the axial direction of the shaft, when each of the plurality of splines is in the fan shape, the plurality of arc-shaped regions formed by the plurality of splines occupy 80% or more of the circumference of the virtual circle as a whole, An electrode catheter.

2. when each of the plurality of splines is in the fan shape, at least two adjacent splines among the plurality of splines have an overlapping region that overlaps with each other when viewed from the axial direction, The electrode catheter according to Claim 1.

3. when each of the plurality of splines is in the fan shape, at least a part of the electrodes of one spline and at least a part of the electrodes of the other spline among the at least two adjacent splines overlap with each other when viewed from the axial direction, The electrode catheter according to Claim 2.

4. when each of the plurality of splines is in the fan shape, non-adjacent splines among the plurality of splines do not have the overlapping region, The electrode catheter according to Claim 2.

5. the tip member fixes at least two adjacent splines among the plurality of splines at a predetermined angular interval around the central axis of the shaft, the shaft fixes each of the at least two adjacent splines at a position rotated by an angle that is 1 time or more and 3 times or less of the angular interval with respect to the tip member around the central axis, The electrode catheter according to Claim 1.

6. when each of the plurality of splines is in the fan 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, The electrode catheter according to Claim 1.

7. When each of the plurality of splines is in the shape of a sector, 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. The electrode catheter according to any one of claims 1 to 6. **Claim 8** 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. With the plurality of splines in contact with the inner wall at the boundary between the pulmonary vein and the left atrium, an electrical pulse can be applied through the plurality of electrodes to cauterize and block the electrical transmission path of atrial fibrillation all at once. Electrode catheter.

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