Electrode catheter and electrification method

Abstract

To provide an electrode catheter or the like capable of easily increasing current density that an electrode causes to flow through a biological tissue inside a body.SOLUTION: An electrode catheter includes: a base material 30 that is provided in a distal end side to be inserted into a body; an electrode 18 that is provided in a planar shape on a surface of at least a part of the base material 30 and applies electricity supplied through a conductor extending from a proximal end side, to a biological tissue BT; and an insulation film 50 that is provided partially on a surface of the electrode 18 and exposes the electrode 18 in a regular pattern. In a cross section having the smallest width of the insulation film 50, an electrification region AA by two exposure portions EP1, EP2 of the electrode 18 in both sides of the insulation film 50 is connected in the biological tissue BT that the insulation film 50 faces.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to an electrode catheter or the like that applies electricity to biological tissue inside the body. [Background technology]

[0002] Patent Document 1 discloses a balloon catheter as an electrode catheter that applies high-frequency power (hereinafter also referred to as high frequency for short) to biological tissue inside the body. A balloon catheter equipped with a balloon that can be expanded inside the body is a type of catheter that is a medical tube that is inserted into the body for diagnosis or treatment. Balloon catheters are inserted into tubular organs inside the body, such as blood vessels, trachea, digestive tract, common bile duct, and pancreatic duct, or their connections (entrances and exits), or holes formed inside the body for diagnosis or treatment (for example, holes punctured from the stomach or duodenal bulb to the common bile duct), to expand or treat the target site.

[0003] The balloon catheter of Patent Document 1 has a band-shaped electrode formed on the surface of the balloon that applies high frequency to biological tissue inside the body. Such a balloon catheter as an electrode catheter is used for catheter ablation (hereinafter also referred to as ablation for short) and radiofrequency ablation (RFA), which are methods for treating arrhythmias and the like. The balloon is inserted up to an abnormal site (the blood vessel itself or surrounding tissue such as a lesion) in a vasculature such as a blood vessel causing the arrhythmia, and is expanded by an expansion fluid such as physiological saline supplied inside, bringing the surface electrode into proximity with or contact with the abnormal site as biological tissue. When the electrode in this state applies high frequency supplied through a lead wire extending from outside the body, the abnormal site is cauterized. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 157100 Summary of the Invention [Problem to be solved by the invention]

[0005] When cauterizing an abnormal area using a balloon catheter or the like, the density of the current (hereinafter simply referred to as current density) that the electrode passes through the biological tissue is important. The strip-shaped electrode in Patent Document 1 has a large surface area because its entire surface is exposed, making it difficult to increase the current density (= current / surface area). This is an issue not only with balloon catheters like those in Patent Document 1, but also with other catheters and electrode catheters in general that apply electricity, such as high-frequency electricity, to biological tissue inside the body.

[0006] The present disclosure has been made in consideration of these circumstances, and aims to provide an electrode catheter or the like that can easily increase the current density that an electrode passes through biological tissue inside the body. [Means for solving the problem]

[0007] In order to solve the above problems, an electrode catheter according to one embodiment of the present disclosure comprises a substrate, an electrode disposed in a planar form on at least a portion of the surface of the substrate and configured to apply electricity to biological tissue, and an insulating film disposed partially on the surface of the electrode and exposing the electrode in a predetermined pattern.

[0008] In this embodiment, the insulating film is partially provided on the surface of the electrode, thereby reducing the effective surface area of ​​the electrode. This makes it easy to increase the current density (= current / effective surface area) that the electrode passes through the biological tissue inside the body. Furthermore, the electrode is exposed in a predetermined pattern by the insulating film, allowing current to pass uniformly through the biological tissue.

[0009] In this specification, the terms "uniform" or "even" in relation to current flow do not mean that the current flow is completely uniform or even, but rather that it may include unevenness or variation in current flow to a degree that does not pose a practical problem in light of the purpose of the electrode catheter, etc., according to the present disclosure. To emphasize this meaning, the terms "substantially uniform" or "substantially uniform" may also be used in some places. Similarly, in this specification, the terms "regular" or "periodic" in relation to a predetermined pattern of an electrode or insulating film do not mean that the pattern is completely regular or periodic, but rather that it may include variation in the pattern to a degree that does not pose a practical problem in light of the purpose of the electrode catheter, etc., according to the present disclosure (thus, strictly speaking, the predetermined pattern according to the present disclosure also encompasses irregular or non-periodic patterns). To emphasize this meaning, the terms "substantially regular" or "substantially periodic" may also be used in some places.

[0010] Another aspect of the present disclosure is a current application method, in which an electrode catheter including a substrate, an electrode provided in a planar form on at least a portion of the surface of the substrate and configured to apply electricity to biological tissue, and an insulating film partially provided on the surface of the electrode and exposing the electrode in a predetermined pattern, is used to place the exposed portions of the insulating film and electrode facing biological tissue in a stacking direction in which the substrate, electrode, and insulating film are stacked, and apply electricity to the biological tissue within a current application region extending in the stacking direction and laterally intersecting the stacking direction using the exposed portions of the electrode, thereby connecting the current application region in the biological tissue opposed by the insulating film in any cross section not intersecting the stacking direction.

[0011] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure. [Effects of the Invention]

[0012] According to the electrode catheter etc. disclosed herein, the current density that the electrode passes through the biological tissue inside the body can be easily increased. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing the overall appearance of a balloon catheter as a first embodiment of an electrode catheter. [Figure 2] FIG. 1 is a perspective view showing the balloon when expanded. [Figure 3] FIG. 1 is a cross-sectional view of a balloon during expansion. [Figure 4] FIG. 2 is a perspective view schematically showing electrodes and a peripheral structure. [Figure 5] FIG. 5 is a schematic enlarged partial cross-sectional view of the electrode and the surrounding structure shown in FIG. 4. [Figure 6] FIG. 2 is a perspective view schematically showing electrodes and a peripheral structure. [Figure 7] Schematic diagram of the insulating film preparation concept. [Figure 8] Schematic diagram of the insulating film preparation concept. [Figure 9] FIG. 10 is a schematic diagram of an ablation system as a second embodiment of an electrode catheter. [Figure 10] FIG. 2 is a schematic perspective view of an electrode assembly. [Figure 11] 10A and 10B show schematic examples of electrode arrangements on each spline. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments for carrying out the present disclosure (hereinafter also referred to as embodiments) will be described in detail with reference to the drawings. In the description and / or drawings, identical or equivalent components, members, processes, etc. are designated by the same reference numerals, and redundant description will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the description and should not be construed as limiting unless otherwise specified. The embodiments are merely examples and do not limit the scope of the present disclosure in any way. Not all features and combinations thereof presented in the embodiments are necessarily essential to the present disclosure. For convenience, the embodiments are presented by breaking them down into components for each function and / or functional group that realize them. However, one component in an embodiment may actually be realized by a combination of multiple separate components, or multiple components in an embodiment may actually be realized by a single integrated component. Furthermore, although multiple embodiments and variants may be disclosed in parallel, any components of each embodiment and / or each variant may be combined in any manner as long as they do not interfere with each other's functions.

[0015] 1 is a schematic diagram showing the overall appearance of a balloon catheter 100 as a first embodiment of an electrode catheter according to the present disclosure. The balloon catheter 100 includes a flexible tubular shaft 10 that is inserted into the body, a handle portion 20 that is attached to the proximal end of the shaft 10 or to the outer side of the body (the right side in FIG. 1), and a balloon 30 that is attached to the distal end of the shaft 10 or to the inner side of the body (the left side in FIG. 1) and that is inflatable with a fluid supplied from the proximal end of the shaft 10. The shaft 10 is composed of a tubular outer shaft 10A that extends from the handle portion 20 to the proximal end of the balloon 30 (a proximal neck portion 351, described below), a tubular inner shaft 11 that extends further from the distal end of the outer shaft 10A and penetrates the balloon 30 in the axial direction (the left-right direction in FIG. 1), and a distal tip 333 that is attached to the distal end of the inner shaft 11.

[0016] The balloon catheter 100 is used for ablation to cauterize a lesion. As described below, a group of electrodes is formed on the surface of the balloon 30, extending in parallel bands along the axial direction from the base end to the tip end. The balloon 30 is inserted up to an abnormal site in a vascular passage such as a blood vessel, and is expanded by an expansion fluid such as saline supplied to the interior via the handle portion 20 and the shaft 10, bringing the group of electrodes on the surface into proximity with or into contact with the abnormal site. The abnormal site is cauterized by applying high-frequency waves supplied through leads (not shown) extending from the handle portion 20 (electrical connector 21, described below) outside the body to the group of electrodes in this state.

[0017] The proximal end of the handle portion 20 is provided with an electrical connector 21, a fluid supply / discharge port 22, and a guidewire port 23. The electrical connector 21 is electrically connected to the group of electrodes on the surface of the balloon 30 via an electrical cable 26, the handle portion 20, the shaft 10 (the outer shaft 10A and / or the inner shaft 11), and a conductor passing through the balloon 30 from the proximal end to the distal end. Therefore, the electrical connector 21 connected to a high-frequency power source (not shown) can apply high-frequency waves to the group of electrodes on the surface of the balloon 30. Furthermore, by connecting the electrical connector 21 to a control device or measuring device constituted by a computer or the like, data such as the potential of the treatment site measured by the group of electrodes on the surface of the balloon 30 may be obtained.

[0018] The fluid supply / discharge port 22 supplies and discharges a fluid for inflating the balloon 30, specifically, an inflation fluid made of sterile distilled water or physiological saline mixed with a contrast agent as needed. The fluid supply / discharge port 22 is in communication with the interior of the balloon 30 via a flow path that runs from the proximal end to the distal end through the fluid supply / discharge tube 27, the handle portion 20, and the shaft 10 (outer shaft 10A). When the fluid supply / discharge port 22 supplies inflation fluid to the interior of the balloon 30, the balloon 30 expands. When the fluid supply / discharge port 22 discharges inflation fluid from the interior of the balloon 30, the balloon 30 contracts. As disclosed in International Application PCT / JP2020 / 005007 (International Publication No. WO2021 / 157100), filed February 8, 2020, the entire contents of which are incorporated herein by reference, a port and a flow path for supplying inflation fluid to the interior of the balloon 30 and a port and a flow path for discharging inflation fluid from the interior of the balloon 30 may be provided separately.

[0019] A guidewire for guiding the balloon 30 to the treatment site is inserted into the guidewire port 23. The guidewire is passed through a hole (space) that penetrates between the proximal and distal ends of the balloon catheter 100. This hole extends from the guidewire port 23 at the proximal end of the balloon catheter 100, through the wire tube 28, the handle portion 20, the shaft 10 (the outer shaft 10A and the inner shaft 11), and the balloon 30, to the distal end of the balloon catheter 100. By inserting the distal end of the balloon catheter 100 from the proximal end of the guidewire that has been inserted to the treatment site in advance, the balloon 30 can reach the treatment site while being guided by the guidewire.

[0020] Inside the tubular shaft 10, in addition to the conductors connecting the electrical connector 21 and the electrodes on the surface of the balloon 30, there are provided a fluid lumen, which is a space through which inflation fluid flows between the fluid supply / discharge port 22 and the inside of the balloon 30, and a wire lumen, which is a space that passes between the guidewire port 23 and the tip of the balloon catheter 100. The tip of the fluid lumen, which is also the tip of the outer shaft 10A, is an open end that terminates inside the balloon 30. The tip of the wire lumen, which is also the tip of the inner shaft 11, is an open end at the tip of the entire balloon catheter 100.

[0021] Thus, of the outer shaft 10A and inner shaft 11 that constitute the shaft 10, the outer shaft 10A, which forms the fluid lumen, terminates inside the balloon 30, while the inner shaft 11, which forms the wire lumen, passes axially through the interior of the balloon 30. In other words, the tip of the inner shaft 11, which also serves as the tip of the entire balloon catheter 100, protrudes distally beyond the tip of the outer shaft 10A, which is located inside the balloon 30. Strictly speaking, the tip of the balloon catheter 100 is formed by the tip tip 333 attached to the tip of the inner shaft 11. If the axial length of the tip tip 333 is large, the tip of the inner shaft 11, which is connected to the proximal end of the tip tip 333, may terminate inside the balloon 30.

[0022] The balloon 30 includes an intermediate section 31 that can be expanded into a cylindrical shape by inflation fluid supplied from the fluid supply / discharge port 22, a distal section 33 that is attached to the shaft 10 (inner shaft 11) distal to the intermediate section 31, and a proximal section 35 that is attached to the shaft 10 (outer shaft 10A) proximal to the intermediate section 31. The intermediate section 31 is a section that axially connects the distal section 33 attached to the shaft 10 and the proximal section 35, and is hereinafter also referred to as a straight section 31.

[0023] The distal end portion 33 of the balloon 30 includes a distal neck portion 331 attached to the shaft 10 (inner shaft 11 or distal tip 333) at its distal end, and a distal tapered portion 332 (hereinafter also referred to as the distal cone portion 332) that is tapered or frustoconical from the distal end of the straight portion 31 toward the distal neck portion 331. The proximal end portion 35 of the balloon 30 includes a proximal neck portion 351 attached to the outer periphery of the shaft 10 (outer shaft 10A) at its proximal end, and a proximal tapered portion 352 (hereinafter also referred to as the proximal cone portion 352) that is tapered or frustoconical from the proximal end of the straight portion 31 toward the proximal neck portion 351.

[0024] 2 is a perspective view showing the balloon 30 during inflation. A plurality of electrodes 40 are formed on the surfaces of the distal end 33 and straight portion 31 of the balloon 30 along the axial direction from the distal end to the proximal end. At least some of the plurality of electrodes 40 may be formed on the surface of the proximal end 35 of the balloon 30. The plurality of electrodes 40 are arranged at any intervals around the circumference of the balloon 30.

[0025] Each electrode 40 is a strip electrode 40 formed on the surface of the distal end 33 and the straight portion 31 of the balloon 30. Each strip electrode 40 is a thin-film electrode or conductive member formed in a strip shape along the axial direction from the distal end to the proximal end. The width of each strip electrode 40 is arbitrary. All strip electrodes 40 may be substantially uniform, or at least some of the strip electrodes 40 may have different widths. The multiple strip electrodes 40 are circumferentially separated from each other by gaps of arbitrary widths along their entire lengths. Since no strip electrodes 40 are present in these gaps, the base material of the balloon 30 is exposed on the surface. The multiple strip electrodes 40 may be connected circumferentially without gaps at least on the distal end of the distal cone portion 332 and / or the distal neck portion 331.

[0026] The configuration of the distal end 33 of the balloon 30 will be described with reference to Figure 3, a cross-sectional view of the balloon 30 during inflation. A wire lumen 12 is formed inside the inner shaft 11, which axially penetrates the balloon 30, allowing a guidewire to pass between it and the guidewire port 23. The outer diameter of the inner shaft 11 is, for example, 1.4 mm, and the inner diameter of the inner shaft 11 (i.e., the outer diameter of the wire lumen 12) is, for example, 1.1 mm. A substantially cylindrical distal tip 333 (part of the shaft 10) is provided at the distal end of the inner shaft 11, covering and protecting the inner shaft 11, including its outer periphery. The outer diameter of the distal tip 333 is, for example, 2.0 mm, and the inner diameter of the distal tip 333 is, for example, 1.1 mm, the same as the inner shaft 11. The distal tip 333 is made of a hard resin or the like. A guidewire passing through the wire lumen 12 can extend out of the balloon catheter 100 from the open ends of the inner shaft 11 and the distal tip 333.

[0027] The distal neck portion 331 of the balloon 30 is attached to the proximal end of the outer periphery of the distal tip 333. A ring electrode 45 is provided as a circumferential electrode on the distal end of the outer periphery of the distal tip 333. The outer diameter of the ring electrode 45 is, for example, 2.22 mm, and the inner diameter of the ring electrode 45 is, for example, 2.08 mm. A strip electrode 40 containing a conductive material or metal such as silver (Ag) is formed to a thickness of approximately 20 μm on the outer periphery of the ring electrode 45 and the balloon 30 by printing or the like so as to fill the gap between the ring electrode 45 and the distal neck portion 331. The ring electrode 45 may be provided after multiple strip electrodes 40 have been formed, connecting their outer peripheries.

[0028] The tip of the band electrode 40 is approximately aligned with the tip of the ring electrode 45, and is located further back toward the proximal end than the tip of the distal tip 333. In other words, the distal tip 333 protrudes distally beyond the band electrode 40 and the ring electrode 45. Therefore, even if the tip of the distal tip 333 comes into contact with the inner wall of a sheath (not shown) that guides the balloon 30 to the treatment site while storing it, or with body tissue, damage to the band electrode 40 and / or the ring electrode 45 is prevented.

[0029] An insulating coating 46 having a thickness of between 10 μm and 20 μm is applied to the outer periphery of the band electrode 40, extending from its tip to the distal neck portion 331 and the distal cone portion 332. This insulating coating 46 is provided to substantially prohibit the output of high frequency waves from the planar region of the band electrode 40 covered thereby (the planar region corresponding to the distal neck portion 331 and the distal cone portion 332). In contrast, the insulating film 50 described below is similar to the insulating coating 46 in that it is provided on the electrode, but differs significantly in that it partially exposes the electrode so that it can output high frequency waves, etc. The insulating coating 46 allows the band electrode 40 to apply high frequency waves to the treatment site from the outer periphery or side of the straight portion 31, which has a stable expanded shape (approximately cylindrical).

[0030] The ring electrode 45 connects the multiple band electrodes 40 circumferentially at the distal end 33 of the balloon 30. This allows the multiple band electrodes 40 to apply high frequency waves of substantially the same voltage to the treatment site. Therefore, even if the balloon 30 inserted inside the body rotates circumferentially, the high frequency waves are reliably applied to the treatment site.

[0031] Although not shown, a conductor extending from the electrical connector 21 on the base end side or outside the body through the electrical cable 26, the handle portion 20, the shaft 10, and the balloon 30 (inner shaft 11) is connected to the ring electrode 45 and / or the band electrode 40 at the distal end of the balloon catheter 100. Therefore, the electrical connector 21 connected to a high-frequency power source (not shown) can apply high-frequency waves to the band electrode 40 on the surface of the balloon 30.

[0032] In the above example, multiple strip-shaped electrodes 40 are provided in parallel on the surface of the balloon 30 serving as a base material, but the shape, arrangement, and number of electrodes 40 are arbitrary as long as high frequency can be appropriately applied to the treatment site. For example, essentially one or a single electrode 40 may be formed to cover most of the straight portion 31 and tip portion 33 of the balloon 30. In this case, one electrode 40 itself also functions as a ring electrode 45, eliminating the need to provide a ring electrode 45 in addition to the electrode 40.

[0033] Furthermore, in the above example, all of the band electrodes 40 were electrically connected by one ring electrode 45, allowing radio frequency waves of substantially the same voltage to be applied to biological tissue within the body, but the radio frequency waves applied by each band electrode 40 may be individually controllable. For example, instead of providing a conductive member such as the ring electrode 45 that connects multiple band electrodes 40, different conductors are provided for each of the multiple band electrodes 40 to which different radio frequency waves are applied. A radio frequency power source (not shown) can apply radio frequency waves of any voltage to each conductor (i.e., each band electrode 40) at any timing.

[0034] For example, the high-frequency power supply (not shown) may be controlled so that multiple band electrodes 40, which are intermittently or discontinuously arranged around the circumference of the balloon 30, sequentially or periodically apply high-frequency waves in a clockwise or counterclockwise direction when viewed from the distal end. In this case, by limiting the number of band electrodes 40 to which high-frequency waves are simultaneously applied, the strength of the high-frequency waves applied to the entire balloon catheter 100 at each time can be reduced. This prevents excessive high-frequency waves from being applied to the treatment site itself or to other surrounding biological tissues, body fluids, etc.

[0035] Next, the electrodes and peripheral structure according to this embodiment will be described. Fig. 4 is a perspective view showing the electrodes and peripheral structure. Fig. 5 is a schematic enlarged partial cross-sectional view of the electrodes and peripheral structure shown in Fig. 4. Note that Fig. 4 and Fig. 5 are upside down.

[0036] 4 is a schematic diagram showing an electrode 18, such as the aforementioned strip electrode 40, provided on the surface (the underside in FIG. 4) of a substrate 30, such as the aforementioned balloon 30. Only a portion of the substrate 30 is shown in this figure. For convenience, the substrate 30 and electrode 18 are shown as planar, but as shown in FIG. 2, the surface of the substrate 30, such as the balloon 30, may be curved, and the electrode 18, such as the strip electrode 40, provided thereon may also be curved.

[0037] 1 to 3, a base material 30 such as a balloon 30 is provided on the distal end side of an electrode catheter such as a balloon catheter 100, which is to be inserted into the body. An electrode 18 such as a band electrode 40 is provided planarly on at least a portion of the surface of the base material 30 such as a balloon 30, and applies electricity such as high frequency electricity supplied through a conductor 47 extending from a proximal electrical connector 21 to biological tissue. Although detailed illustration is omitted, as described above, the conductor 47 passes through the electrical cable 26, the handle portion 20, the shaft 10 (the outer shaft 10A and / or the inner shaft 11), and the balloon 30 from the proximal electrical connector 21 toward the distal band electrode 40 (or the ring electrode 45).

[0038] An insulating film 50 having a predetermined pattern is partially provided on the surface (the lower surface in FIG. 4) of the electrode 18. For example, this insulating film 50 is formed in a regular or periodic pattern, and exposes the electrode 18 in the regular or periodic pattern.

[0039] In this way, because the insulating film 50 is partially provided on the surface of the electrode 18, the effective surface area through which the electrode 18 passes current is reduced. This makes it easy to increase the current density (=current / effective surface area) that the electrode 18 passes through the biological tissue inside the body. For example, if the insulating film 50 covers 1 / N (N is any number greater than 1) of the area of ​​the electrode 18, the effective surface area through which the electrode 18 passes current through the biological tissue inside the body is reduced to (N-1) / N compared to when the partial insulating film 50 is not provided. In this way, by increasing the area covered by the insulating film 50 (reducing N), the current density that the electrode 18 passes through the biological tissue inside the body can be increased (approximately N / (N-1) times when the partial insulating film 50 is not provided), thereby improving the cauterization efficiency. Here, since there is no need to increase the high-frequency voltage applied to the electrode 18 by a high-frequency power supply (not shown) to increase the current density, a high level of safety can be maintained. In particular, if the high-frequency voltage is high, the biological tissue may be cauterized to a depth greater than necessary, which may cause an undesirable reaction in the living body. However, according to this embodiment, the high-frequency voltage can be kept low, allowing for "thin" cauterization to the minimum necessary depth.

[0040] The above N is arbitrary and may be any natural number greater than 1, such as 2, 3, 4, 5, 6, 7, or 8. When N=2, the effective surface area of ​​electrode 18 is halved and the current density is doubled. When N=3, the effective surface area of ​​electrode 18 is 2 / 3 and the current density is 3 / 2 times higher.

[0041] As described above, a desired current density can be achieved by adjusting the area that the insulating film 50 covers over the electrode 18. Furthermore, since the electrode 18 is exposed in a regular or periodic pattern by the insulating film 50 having a regular or periodic pattern, current can be passed through the biological tissue uniformly or evenly.

[0042] The regular formation pattern of the insulating film 50 and the resulting regular exposure pattern of the electrodes 18 may be any pattern as long as they can achieve the continuity of the current-carrying area AA in the living tissue, as will be described later.

[0043] For example, as shown in FIG. 4 , the insulating film 50 may be regularly provided in each mesh region of the mesh pattern to expose the electrode 18 in a regular mesh pattern. In this case, the insulating film 50 is composed of a large number of small insulating films arranged two-dimensionally on the surface of the electrode 18. The small insulating films are separated from each other at regular intervals in each two-dimensional direction, and the intervals form exposed portions of the electrode 18. Thus, in the example of FIG. 4 , the small insulating films are distributed discretely and periodically so as to be isolated on the surface of the electrode 18. The small insulating films may have different shapes, but preferably have substantially the same shape. For example, as shown in FIG. 4 , the small insulating films are formed in substantially the same circular, dot, or point shape. However, the shape of each small insulating film is arbitrary, and may be, for example, any polygonal shape, any linear or curved line segment, or a long linear shape (e.g., striped or striped) or curved shape (e.g., wavy or broken line) that crosses the surface of the electrode 18.

[0044] Alternatively, as shown in FIG. 6 , the insulating film 50 may be provided in a regular mesh pattern, with the electrode 18 being regularly exposed in each mesh region of the mesh pattern. In this case, the exposed portion of the electrode 18 is composed of numerous small exposed portions arranged two-dimensionally on the surface of the electrode 18. The small exposed portions are separated from each other at regular intervals in each two-dimensional direction, and the insulating film 50 in the mesh pattern is arranged in these intervals. Thus, in the example of FIG. 6 , the small exposed portions are distributed discretely and periodically so as to be isolated on the surface of the electrode 18. The small exposed portions may have different shapes from one another, but preferably have substantially the same shape. For example, as shown in FIG. 6 , the small exposed portions are formed in substantially the same circular, dot, or spot shape. However, the shape of each small exposed portion is arbitrary, and may be, for example, any polygonal shape, any straight or curved line segment, or a long straight line (e.g., striped or striped) or curved line (e.g., wavy or folded line) that crosses the surface of electrode 18.

[0045] As shown in the partially enlarged cross-sectional view of FIG. 5 , the electrode 18 is provided planarly on the surface of the substrate 30 (the upper surface in FIG. 5 ). Note that an intervening material, such as an adhesive or an auxiliary agent, may be present between the electrode 18 and the substrate 30, such as the balloon 30. Such an intervening material is also considered part of the substrate 30. The electrode 18 includes a conductive first material 41. The first material 41 may be any conductive material, such as a metal material, such as silver (Ag). The first material 41 alone is sufficient for the electrode 18 to perform its basic function of applying high-frequency or other electricity to biological tissues within the body. However, as shown in FIG. 2 , a second material 42 different from the first material 41 is preferably added to impart desired flexibility to the bendable electrode 18. The composition ratio and weight ratio of the first material 41 and the second material 42 in the electrode 18 are arbitrary, and although it is typically expected that the first material 41 will be greater than the second material 42, the second material 42 may be greater than the first material 41.

[0046] Examples of second material 42 include resin materials such as polyurethane and polyamide resin, but any material may be used as long as it can impart flexibility to electrode 18 or enhance bonding with insulating film 50, as described below. As shown schematically in FIG. 5 , second material 42 may be dispersed in the form of particles of any size or shape within first material 41, which is the main material, or may be physically mixed or chemically bonded to first material 41 in a manner that is substantially indistinguishable from first material 41. Second material 42, which is a resin material, is typically expected to be insulating, but conductive second material 42 may also be used.

[0047] The substrate 30, such as a balloon 30, on whose surface an electrode 18, such as a strip electrode 40, is provided is made of a resin material, such as a nylon-based resin. To prevent the electrode 18 from peeling off from the substrate 30, it is preferable that a portion of the back surface (the lower surface in FIG. 5) of the electrode 18 extends from the surface of the substrate 30 to the interior, as shown schematically in FIG. 5. For example, the configuration shown in FIG. 5 can be achieved by forming the electrode 18 after roughening the surface of the substrate 30 by etching or the like. Alternatively, when forming the electrode 18 on a substrate 30 with a flat surface, a portion of the back surface of the electrode 18 may be impregnated into the substrate 30 so that it takes root.

[0048] As mentioned above, nylon-based resins, which have high heat resistance, are commonly used as materials for the substrate 30 of the balloon 30, etc. However, for substrates 30 where heat resistance is not necessarily important, materials with relatively low heat resistance may be used. In this case, the substrate 30 may be made of a material of the same type or similar family as the second material 42 contained in the electrode 18. For example, the substrate 30 may be made of a polyurethane that is the same or different from the second material 42. In this case, the polyurethane as the second material 42 contained in the electrode 18 and the polyurethane constituting the substrate 30 are strongly bonded chemically or physically, thereby achieving sufficient adhesion or peel resistance even without a portion of the back side of the electrode 18 extending into the substrate 30, as shown schematically in FIG. 5 . Note that, in this specification, two materials being chemically “similar” or “similar” means that the two materials have the same or corresponding functional groups that chemically bond to each other.

[0049] As shown schematically in the partially enlarged cross-sectional view of FIG. 5, the insulating film 50 is partially provided on the surface of the electrode 18 (the upper surface in FIG. 5). The insulating film 50 includes an insulating third material that bonds with the second material 42 in the electrode 18. This third material may be the same type or a material of the same family as the second material 42, such as polyurethane, contained in the electrode 18. For example, the insulating film 50 may be made of a resin material, such as polyurethane, that is the same as or different from the second material 42.

[0050] In this case, the resin material such as polyurethane as the third material contained in the insulating film 50 is strongly chemically or physically bonded to the resin material such as polyurethane as the second material 42 contained in the electrode 18, so that sufficient adhesion or peel resistance can be achieved even when the insulating film 50 is provided discretely on the electrode 18 as schematically shown in Figures 4 and 5. Note that sufficient adhesion or peel resistance can be obtained by simply printing the insulating film 50 containing the same type or type of material as the electrode 18 (second material 42) on the electrode 18, but the adhesion or peel resistance can be further improved by performing an additional bonding process such as heating or pressure bonding.

[0051] As described above, the insulating film 50 can reduce the effective surface area of ​​the electrode 18 and increase the current density applied to biological tissue inside the body. On the other hand, since the portion of the surface of the electrode 18 covered with the insulating film 50 cannot output current, it is preferable to adjust the size, arrangement, shape, etc. of the insulating film 50 so that the current output from the exposed portion of the electrode 18 can sufficiently reach directly below the insulating film 50. Figure 7 schematically shows the concept of adjusting the insulating film 50 in this way.

[0052] In this figure, in the stacking direction (vertical direction in FIG. 7) in which the base material 30, the electrode 18, and the insulating film 50 are stacked, the lower surfaces of the insulating film 50 and exposed portions EP1 and EP2 of the electrode 18 face the biological tissue BT. Also, FIG. 7 schematically shows the configuration in a cross section (in other words, a cross section that does not intersect with the stacking direction or that includes the stacking direction) extending in the stacking direction (and in a lateral direction perpendicular to the stacking direction (horizontal direction in FIG. 7)).

[0053] 7, the lower surface of the substrate 30 on which the electrode 18 and insulating film 50 are formed faces the underlying biological tissue BT. The insulating film 50 on the lowermost surface is in contact with the biological tissue BT, and a minute body fluid space FS exists between the two adjacent exposed portions EP1, EP2 of the electrode 18 and the biological tissue BT. The body fluid space FS contains body fluids such as blood that conduct electricity more easily than the biological tissue BT, and therefore can be treated as essentially part of the electrode 18.

[0054] Each exposed portion EP1, EP2 of electrode 18 applies a high frequency to biological tissue BT through a body fluid space FS directly below it (below in the stacking direction, which is the up-down direction in FIG. 7). Here, the high frequency applied to biological tissue BT is considered to spread in a substantially circular or spherical shape with each application point as its center. In the example of FIG. 7, the high frequency is assumed to be transmitted within a circle of radius r with each application point as its center. The radius r is determined by the voltage applied to electrode 18, the current density output by each exposed portion EP1, EP2 of electrode 18, the physical properties of the biological tissue BT to which the high frequency is applied, the force with which electrode 18 and / or insulating film 50 are pressed against the biological tissue BT, etc.

[0055] In the region directly below each exposed portion EP1, EP2 of electrode 18, it is believed that the high frequency waves reach at least a depth corresponding to the radius r from each application point. Furthermore, in the region directly below insulating film 50, it is believed that the high frequency waves reach within a circle of radius r centered at the end point of body fluid space FS, which is the nearest application point. The region in biological tissue BT where the high frequency waves are believed to reach is schematically shown in FIG. 7 as a current-carrying area AA. That is, each exposed portion EP1, EP2 of electrode 18 applies electricity, such as high frequency waves, to biological tissue BT within the current-carrying area AA directly below and to the sides thereof (i.e., directly below insulating film 50).

[0056] 7, it is preferable that the current-carrying areas AA formed by the two exposed portions EP1, EP2 on both sides of each small portion of the insulating film 50 are connected directly below the insulating film 50 (i.e., the biological tissue BT facing the insulating film 50). In this case, the high frequency also reaches the biological tissue BT directly below the insulating film 50, so that appropriate ablation or the like can be performed throughout the entire biological tissue BT to be treated. Note that the connection of the current-carrying areas AA directly below the insulating film 50 can be observed as connected cauterization marks in the biological tissue BT facing the insulating film 50.

[0057] To achieve this desirable state, it is preferable that the distance d between the two exposed portions EP1, EP2 on both sides of each small portion of the insulating film 50 be equal to or less than the sum of the depths of the conductive areas AA directly below the exposed portions EP1, EP2. In the example of Figure 7, the depth of the conductive areas AA directly below the exposed portions EP1, EP2 is radius r, so it is preferable that d≦2r. Note that the width d of each portion in the pattern of the insulating film 50 can be adjusted depending on the physical properties of the biological tissue BT to be ablated, the voltage applied to the electrode 18, etc., but is expected to be small, for example, about 50 nm.

[0058] It is preferable that the width d of each portion in the pattern of the insulating film 50 be as small as possible while satisfying the above-mentioned conditions such as d≦2r. Furthermore, even when the insulating film 50 is formed in a mesh pattern, as shown in Fig. 6, it is also preferable that the width d of each portion of the insulating film 50 be as small as possible. In this case, the width d of each portion of the insulating film 50 is preferably 1 mm or less, more preferably 100 µm or less, and even more preferably 10 µm or less.

[0059] The regular or periodic pattern of the insulating film 50 satisfies the preferable condition such as d≦2r for an arbitrary point P on the insulating film 50, and the minimum width (d min ) is preferably established in a cross section. As illustrated in FIG. 8 as viewed in the stacking direction, consider a case where an insulating film 50 is formed by a plurality of small elliptical insulating films 51. In this example, the width along the side of each small insulating film 51 (in the direction of the paper in FIG. 8) including an arbitrary point P on each small insulating film 51 is the minimum (d min ) at the cross section where d min 8, when the center of the elliptical small insulating film 51 is selected as the point P, the width of the small insulating film 51 including the center point P is the minimum (d min ) in a cross section containing the minor axis of the ellipse, d min7, the conductive regions formed by the two exposed portions EP1 and EP2 on both sides (left and right sides in FIG. 8) of the short axis of the elliptical small insulating film 51 (50) are connected in the biological tissue BT directly below the insulating film 51.

[0060] On the other hand, the conductive regions formed by the two exposed portions on both sides (upper and lower sides in FIG. 8) of the long axis of the elliptical small insulating film 51 may not be connected in the biological tissue BT directly below the insulating film 51. As shown in FIG. 8, when the length of the long axis of the elliptical small insulating film 51 is d max (the maximum width of the small insulating film 51 relative to the center point P), max ≦2r does not have to be satisfied. In other words, d max 8 on the long axis of the elliptical small insulating film 51, the current-carrying region due to the upper electrode exposed portion in FIG. 8 and the current-carrying region due to the lower electrode exposed portion in FIG. 8 are not connected. However, "for any point P (not limited to the center point) on the insulating film 50, the width along the side of the insulating film 50 including the point P is the minimum (d min ) at the cross section d min 8 reaches the long axis, the current-carrying areas formed by the exposed electrode portions on the left and right sides in FIG. 8 reach the long axis, and as a result, the current-carrying areas are continuous even on the long axis. Therefore, the continuity of the current-carrying area AA in the biological tissue BT directly below the elliptical small insulating film 51 can be achieved.

[0061] FIG. 9 is a schematic diagram of an ablation system 1 as a second embodiment of an electrode catheter according to the present disclosure. Components similar to those of the balloon catheter 100 according to the first embodiment are assigned the same reference numerals, and redundant explanations will be omitted. In this figure, some of the components of the ablation system 1 are shown as functional blocks. The ablation system 1 performs ablation on an affected area 2 of a patient. An example of the affected area 2 is an organ experiencing arrhythmia. The ablation system 1 includes a catheter 4, a return electrode 6, and a power supply 8.

[0062] The catheter 4 in the example shown in the figure has a shaft 10, an electrode assembly 13, and a handle 14. The shaft 10 is made of a flexible tubular body, and at least the distal end thereof is inserted into the patient's body. The shaft 10 is made of a known flexible material, including resins such as polyolefin, polytetrafluoroethylene, polyether block amide, and polyamide. The shaft 10 has, for example, a multi-lumen structure having multiple lumens. Various thin wires (not shown), such as conducting wires and operating wires, as well as an inner shaft 11 (see FIG. 10), which will be described later, are inserted into the lumens.

[0063] An electrode assembly 13 is provided at the tip of the shaft 10. Fig. 10 is a schematic perspective view of the electrode assembly 13. The electrode assembly 13 has a plurality of splines 16 and a plurality of electrodes 18. Fig. 9 shows the splines 16 in a folded state, while Fig. 10 shows the splines 16 in an unfolded state.

[0064] Each spline 16 in the folded state is a linear body extending along the axial direction of the shaft 10 and is made of the same flexible material as the shaft 10. The electrode assembly 13 illustrated in FIG. 10 has a first spline 16a, a second spline 16b, a third spline 16c, a fourth spline 16d, a fifth spline 16e, and a sixth spline 16f. However, the number of splines 16 is not limited to six, and any number may be used. Hereinafter, the first spline 16a to the sixth spline 16f will also be collectively referred to as splines 16.

[0065] The multiple splines 16 are spaced apart around the central axis of the shaft 10. The distal end of each spline 16 is connected to a distal tip 333. The proximal end of each spline 16 is inserted into the shaft 10 from its distal end and fixed therein. The distal tip 333 is connected to the distal end of an inner shaft 11. The inner shaft 11 passes through the lumen of the shaft 10, and its proximal end is connected to the handle 14. The inner shaft 11 can be advanced and retreated in both the distal and proximal directions relative to the shaft 10 by operating the handle 14.

[0066] When the inner shaft 11 is retracted toward the base end while each spline 16 extends in a substantially straight line (e.g., FIG. 9), the distal tip 333 at the distal end of each spline 16 also displaces toward the base end. As a result, as shown in FIG. 10, each spline 16 curves so as to bulge outward with the inner shaft 11 at the center, and the electrode assembly 13 assumes a basket shape. On the other hand, when the inner shaft 11 is pushed toward the distal end while each spline 16 is curved (e.g., FIG. 10), the distal tip 333 at the distal end of each spline 16 also displaces toward the distal end. As a result, as shown in FIG. 9, each spline 16 becomes substantially straight along the inner shaft 11, and the electrode assembly 13 is folded. The term "basket shape" comes from the fact that the shape of the multiple splines 16 resembles the curved pattern on the surface of a basketball.

[0067] Each spline 16 is provided with a plurality of electrodes 18. The plurality of electrodes 18 are arranged at predetermined intervals along the longitudinal direction of the spline 16. Each electrode 18 covers at least a portion of the circumferential range of the spline 16. Here, the electrode 18 may be an annular electrode that covers the entire circumferential range of the spline 16. However, because the electrode 18 according to this embodiment has high adhesion or peeling resistance as described above, it can also be configured as a partial annular electrode that covers a portion of the circumferential range of the spline 16, as described below.

[0068] Each electrode 18 is made of a metal with good electrical conductivity, such as platinum, gold, silver, copper, aluminum, or stainless steel, or an alloy thereof. In the electrode assembly 13 illustrated in Fig. 10, a first electrode 18a, a second electrode 18b, a third electrode 18c, and a fourth electrode 18d are provided on each spline 16. However, the number of electrodes 18 provided on each spline 16 is not limited to four, and at least one electrode 18 is sufficient. Hereinafter, the first electrode 18a to the fourth electrode 18d will also be collectively referred to as electrodes 18.

[0069] The distal end of each conductor 47 as shown in Fig. 4 is connected to each electrode 18. The conductor 47 passes through the lumen of the shaft 10, and its proximal end is connected to an electrical connector in the handle 14 (similar to electrical connector 21 in Fig. 1). Each conductor 47 is electrically connected to a power supply 8 such as a high-frequency power supply via the electrical connector in the handle 14. The power supply 8 applies electricity such as high-frequency power to the multiple electrodes 18 through the conductors 47.

[0070] The handle 14 provided at the base end of the shaft 10 is disposed outside the body when the catheter 4 is in use, and is grasped or operated by an operator such as a doctor. The handle 14 has a main body portion grasped by the operator and an operating portion for advancing and retracting the inner shaft 11. When the inner shaft 11 is displaced toward the base end relative to the shaft 10 in response to operation through the operating portion, the electrode assembly 13, which was in a folded state, unfolds or spreads out in a direction intersecting the central axis of the shaft 10. On the other hand, when the inner shaft 11 is displaced toward the tip end relative to the shaft 10 in response to operation through the operating portion, the electrode assembly 13, which was in a folded state, unfolds. An electrical connector is provided in the main body portion. The catheter 4 may also have an irrigation mechanism that sprays irrigation fluid, such as saline, from the tip end during ablation.

[0071] The return electrode 6 is attached to the surface of the patient's body during ablation. The return electrode 6 is electrically connected to a power supply 8. During ablation, the power supply 8 applies a voltage V between each electrode 18 and the return electrode 6. out is applied.

[0072] The power supply device 8 includes an input unit 24, a power supply unit 25, a control unit 29, and a display unit 3. The input unit 24 is configured with a dial, buttons, a touch panel, etc., and is operated by the operator of the ablation system 1. The operator can input various setting values ​​and signals instructing operations to the power supply device 8 through the input unit 24. Note that at least some of the setting values ​​may be set in advance, such as at the time of product shipment, and stored in a memory device or the like within the power supply device 8. Signals indicating the setting values, etc., are sent from the input unit 24 to the control unit 29.

[0073] The power supply unit 25 applies an ablation voltage V to the electrode 18 and the return electrode 6 in accordance with a control signal CTL given from the control unit 29. out The power supply unit 25 is configured with a power supply circuit such as a switching regulator. The control unit 29 controls the operation of the entire power supply device 8 and executes various arithmetic processing. The control unit 29 is configured with a microcomputer or the like. The control unit 29 controls the voltage V applied to the electrode 18 and the return electrode 6 by sending a control signal CTL to the power supply unit 25. out The display unit 3 displays various information to the outside. The display unit 3 is configured by a liquid crystal display, a CRT display, an organic EL display, or the like.

[0074] The ablation system 1 according to this embodiment performs ablation on the affected area 2 by, for example, irreversible electroporation (IRE). Because IRE is non-thermal, it can suppress damage to tissues and nerves located around the affected area 2. For example, when performing pulmonary vein dissection to treat atrial fibrillation, it can suppress damage to the esophagus and phrenic nerve around the affected area, preventing the occurrence of complications such as esophageal fistula and phrenic nerve paralysis.

[0075] In IRE, pulsed electric field ablation (PFA) is performed. PFA is an ablation technique that kills cells in the affected area 2 (i.e., forms a lesion in the affected area 2) using a pulsed electric field based on a high voltage applied between each electrode 18 and the return electrode 6. Because the electric field tends to reflect at the boundaries between tissues, damage to adjacent tissues is suppressed when the affected area 2 is cauterized.

[0076] Although detailed explanation will be omitted, with the electrode assembly 13 inserted into the affected area 2 inside the patient's body through a blood vessel or the like, the control unit 29 controls the power supply unit 25 to apply a voltage to each electrode 18 in sequence according to a predetermined rule. For example, the control unit 29 controls the power supply unit 25 to apply a voltage to some of the electrodes 18 consecutively multiple times, and then to some of the other electrodes 18 consecutively multiple times. The "some of the electrodes 18" and the "other some of the electrodes 18" may each refer to one electrode 18, or may refer to two or more electrodes 18. The fact that voltages are being applied consecutively to each electrode 18 in sequence can be confirmed, for example, by connecting a measuring device such as an oscilloscope to each of the electrodes 18.

[0077] 11 is a schematic diagram showing an example of the arrangement of the electrodes 18 on each spline 16. In this diagram, the spline 16 is simply shown as a long, cylindrical member, and the electrode 18 is shown as a plate-like member that covers part of the outer periphery of the spline 16.

[0078] 5, the electrode 18 having the insulating film 50 formed on its surface is provided in a planar form on the surface of the spline 16 serving as a base material. When viewed in the extension direction of the spline 16 serving as an elongated member, the electrode 18 is provided so as to cover the outer periphery of the spline 16 or a portion of the circumferential range of the spline 16. In other words, the electrode 18 is not a ring-shaped electrode that covers the entire outer periphery of the spline 16, but is formed as a non-ring-shaped electrode that covers only a portion of the outer periphery of the spline 16.

[0079] As shown schematically in FIG. 11, such a non-ring-shaped electrode 18 (and the insulating film 50 on its surface) is provided on the outer periphery of the spline 16, which faces the biological tissue BT as the target of treatment such as cauterization. Each spline 16 in the basket-shaped electrode assembly 13 shown in FIG. 10 contacts the biological tissue BT on its outer surface (the lower surface in FIG. 11) as viewed from the central inner shaft 11, so the non-ring-shaped electrode 18 may be provided on such an outer portion. Such a non-ring-shaped electrode 18 can prevent unnecessary high-frequency waves from being applied to surrounding biological tissues other than the biological tissue BT as the treatment target, or to bodily fluids such as blood. Furthermore, because the non-ring-shaped electrode 18 is provided partially on the outer periphery of the spline 16, the size or outer diameter of the entire spline 16, including the electrode 18, can also be reduced.

[0080] While the non-ring-shaped electrode 18 has the above advantages, it has the disadvantage of being more easily peeled off from the spline 16 than a ring-shaped electrode that surrounds the entire circumference of the spline 16. However, as described above with reference to FIG. 5, the electrode 18 and insulating film 50 according to this embodiment have high adhesion or peeling resistance due to the ingenuity of the bond between the surface of the electrode 18 and the substrate 30 (the spline 16 in FIG. 11) and the bond between the materials of the electrode 18 and the insulating film 50 (or the substrate 30). Therefore, the non-ring-shaped electrode 18 according to this embodiment can compensate for the disadvantage of being easily peeled off, while enjoying the advantage of being able to reduce the application of unnecessary high frequency waves to areas other than the treatment target.

[0081] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0082] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROMs, RAMs, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs. [Explanation of symbols]

[0083] 1 ablation system, 4 catheter, 8 power supply unit, 10 shaft, 13 electrode assembly, 16 spline, 18 electrode, 30 balloon, 41 first material, 42 second material, 47 lead wire, 50 insulating film, 100 balloon catheter.

Claims

1. A substrate; an electrode provided in a planar form on at least a portion of the surface of the substrate and configured to apply electricity to biological tissue; an insulating film partially provided on a surface of the electrode, exposing the electrode in a predetermined pattern; An electrode catheter comprising:

2. In a stacking direction in which the base material, the electrode, and the insulating film are stacked, exposed portions of the insulating film and the electrode face the biological tissue, The exposed portion of the electrode applies electricity to the biological tissue within a current-carrying region extending in the stacking direction and in a lateral direction intersecting the stacking direction; In any cross section not intersecting the stacking direction, the conductive regions are connected in the biological tissues facing the insulating films. The electrode catheter of claim 1 .

3. 3. The electrode catheter according to claim 2, wherein, for any point on the insulating film, in a cross section that includes the point and has the smallest width along the side of the insulating film, the conductive regions formed by the two exposed portions on both sides of the insulating film are connected in the biological tissue that the insulating film faces.

4. 4. The electrode catheter according to claim 3, wherein the distance between the two exposed portions on either side of the insulating film in the cross section is equal to or less than the sum of the depths of the conductive regions in the biological tissue that the exposed portions face.

5. the electrode includes a conductive first material and a second material different from the first material; the insulating film includes an insulating third material that bonds with the second material; 5. An electrode catheter according to any one of claims 1 to 4.

6. The electrode catheter of claim 5 , wherein the second material and the third material are the same or different resin materials that bond to each other.

7. The electrode catheter of claim 6 , wherein the second material and the third material are the same or different polyurethane or polyamide resins bonded to each other.

8. the base material is a member extending in an extension direction, the electrode and the insulating film cover a part of the outer periphery of the member when viewed in the extending direction.

6. The electrode catheter of claim 5.

9. The electrode catheter according to claim 8 , wherein the electrode and the insulating film are provided on a portion of the outer periphery of the member that faces the biological tissue.

10. 5. The electrode catheter according to claim 1, wherein the insulating film is provided in each mesh area of ​​a mesh pattern so as to expose the electrodes in the mesh pattern.

11. The electrode catheter according to claim 1 , wherein the insulating film is provided in a mesh pattern, and the electrodes are exposed in each mesh area of ​​the mesh pattern.

12. A shaft is inserted into the body, The base material is a balloon attached to the distal end side of the shaft and expandable by a fluid supplied from the proximal end side of the shaft.

5. An electrode catheter according to any one of claims 1 to 4.

13. A substrate; an electrode provided in a planar form on at least a portion of the surface of the substrate and configured to apply electricity to biological tissue; an insulating film partially provided on a surface of the electrode, exposing the electrode in a predetermined pattern; Through an electrode catheter comprising In a stacking direction in which the base material, the electrode, and the insulating film are stacked, exposed portions of the insulating film and the electrode are placed opposite the biological tissue; Applying electricity to the biological tissue within a current-carrying region extending in the stacking direction and laterally intersecting therewith by the exposed portion of the electrode; In any cross section not intersecting the stacking direction, the insulating film connects the conductive regions in the opposing biological tissues. How to energize.

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