Ablation catheter

Abstract

To provide an ablation catheter capable of cooling an ablation electrode evenly and suppressing generation of clot.SOLUTION: An ablation catheter includes: a tube 2 having a distal end and a proximal end; a liquid supply part arranged on a distal side of the tube 2; a liquid supply lumen 3 which is arranged inside the tube 2 and is a flow channel for liquid supplied by the liquid supply part; an ablation electrode 4 arranged in a distal part of the tube 2; and a movable body 7 arranged in the distal part of the tube 2 and moves by a liquid flow supplied by the liquid supply part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an ablation catheter. [Background technology]

[0002] Ablation catheters are therapeutic devices that deliver high-frequency waves to the distal tip to cauterize lesions within the heart. Because of the risk of thrombus formation due to temperature rise during ablation, ablation catheters with irrigation functions that cool the distal tip are now being used. While cooling the distal tip by irrigation can reduce the risk of thrombus formation, there is still room for improvement in terms of cooling functionality.

[0003] The invention described in Patent Document 1 is a radiofrequency heating balloon catheter that heats the tissue in contact with the balloon as uniformly as possible to provide thermal treatment to the affected area. This device heats the balloon by using radiofrequency waves to heat the fluid inside the balloon. It discloses that, in order to eliminate temperature unevenness inside the balloon, an electrode wire that heats the fluid inside the balloon is rotated. Furthermore, the invention described in Patent Document 2 is a conduction heating catheter that necrotizes and excises tissue by heating. It is provided with a fluid circulation device that circulates a heat transfer fluid through the heating device so as to rapidly supply sufficient heat to the fluid without contaminating the catheter's heating element. One such example is a fluid heating device equipped with an impeller rotated by a motor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-102850 [Patent Document 2] Special Publication No. 2001-515368 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 discloses that a heating element is rotated to equalize the temperature inside the balloon of a balloon catheter. When this is applied to the distal tip of an ablation catheter, there is a problem that it is difficult to rotate a cooling element inside the distal tip when the distal tip has a very narrow lumen. The catheter of Patent Document 2 requires an external output such as a motor for rotation, which necessitates a new external output device for the ablation catheter. The present invention aims to solve the above problems and provide a mechanism suitable for ablation catheters. [Means for solving the problem]

[0006] The ablation catheter of the present invention, which solves the above problems, has a liquid supply lumen inside a tube that serves as a liquid flow path, a movable body that moves with the flow of liquid in the distal portion of the tube, and achieves uniform cooling inside the catheter, thereby suppressing thrombosis and complications. That is, the ablation catheter of the present invention is characterized by comprising a tube having a distal end and a proximal end, a liquid supply unit located on the proximal side of the tube, a liquid supply lumen located inside the tube that serves as a flow path for liquid supplied from the liquid supply unit, an ablation electrode located in the distal portion of the tube, and a movable body located in the distal portion of the tube that moves with the flow of liquid supplied from the liquid supply unit.

[0007] The movable body is preferably a rotation mechanism that rotates at a predetermined position in the distal portion of the tube by the flow of liquid supplied from the liquid supply portion.

[0008] Preferably, the ablation electrode has an internal space, the liquid supply lumen is in communication with the internal space of the ablation electrode, and the movable body is located somewhere between the liquid supply lumen and the internal space of the ablation electrode. More preferably, the movable body is located in the internal space of the ablation electrode. Also, the ablation electrode is preferably a tip located at the distal end of the tube.

[0009] The ablation catheter preferably further comprises a liquid return lumen disposed inside the tube and serving as a flow path for returning the liquid supplied to the internal space of the ablation electrode to the proximal side of the tube.

[0010] It is also preferable that the ablation catheter has holes on the side or tip of the ablation electrode.

[0011] The rotation axis of the rotation mechanism may be perpendicular to the longitudinal direction of the tube, or may be parallel to the longitudinal direction of the tube.

[0012] The rotating part of the rotation mechanism is preferably an impeller, a water wheel, a gear, or a screw. The rotating part of the rotation mechanism preferably has a blade, and the blade preferably has a depression for receiving the liquid. The blade is preferably disposed obliquely with respect to the extension direction of the rotation axis of the rotating part.

[0013] The ablation catheter may have an inner tube disposed within the fluid supply lumen, a radio frequency power source disposed proximally of the tube, and a lead wire connecting the ablation electrode to the radio frequency power source disposed within the inner tube. [Effects of the Invention]

[0014] According to the ablation catheter of the present invention, a liquid supply lumen, which is a liquid flow path, is provided inside the tube, and a movable body that moves with the flow of the liquid is provided in the distal portion of the tube, so that the movable body can agitate the liquid flowing inside the tube, disturb the flow, or generate an intentional water flow, thereby uniformly cooling the ablation electrode provided in the distal portion of the tube and suppressing the formation of thrombi. [Brief explanation of the drawings]

[0015] [Figure 1]1 shows a schematic diagram of an ablation catheter according to an embodiment of the present invention. [Figure 2] 2 shows an example of a longitudinal cross-sectional view of the distal portion of the tube of the ablation catheter shown in FIG. 1. [Figure 3] 3 shows a cross-sectional view perpendicular to the longitudinal direction of the distal portion of the tube shown in FIG. 2. [Figure 4] 2 illustrates another example of a cross-sectional view along the longitudinal direction of the distal portion of the tube of the ablation catheter shown in FIG. 1. [Figure 5] 2 illustrates another example of a cross-sectional view along the longitudinal direction of the distal portion of the tube of the ablation catheter shown in FIG. 1. [Figure 6] 2 illustrates another example of a cross-sectional view along the longitudinal direction of the distal portion of the tube of the ablation catheter shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, reference should be made to the specification and other drawings. The dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0017] An ablation catheter according to an embodiment of the present invention comprises a tube having a distal end and a proximal end, a liquid supply section disposed on the proximal side of the tube, a liquid supply lumen disposed inside the tube and serving as a flow path for liquid supplied from the liquid supply section, an ablation electrode disposed in the distal portion of the tube, and a movable body disposed in the distal portion of the tube that moves with the flow of liquid supplied from the liquid supply section.

[0018] Figures 1 to 6 show examples of the configuration of an ablation catheter according to an embodiment of the present invention. Figure 1 shows a schematic overall view of the ablation catheter, Figures 2 and 4 to 6 show longitudinal cross-sectional views of examples of the configuration of the distal portion of the tube of the ablation catheter shown in Figure 1, and Figure 3 shows a cross-sectional view perpendicular to the longitudinal direction of the distal portion of the tube shown in Figure 2.

[0019] As shown in FIG. 1, the ablation catheter 1 includes a tube 2 and an ablation electrode 4 disposed at the distal end of the tube 2. The tube 2 extends longitudinally, and a proximal side and a distal side are defined relative to the longitudinal direction. The proximal side refers to the direction toward the user, i.e., the surgeon, relative to the direction of extension of the tube 2, while the distal side refers to the opposite side of the proximal side, i.e., the direction toward the treatment target. The proximal and distal sides of the ablation catheter 1 are also defined based on the longitudinal direction of the tube 2. The direction perpendicular to the longitudinal direction is referred to as the radial direction. The ablation catheter 1 can cauterize tissue, for example, a lesion in the heart, by passing high-frequency current through the ablation electrode 4. The high-frequency current is supplied to the ablation electrode 4 from a high-frequency power source 15 connected to the proximal end of the tube 2 via, for example, a conductor.

[0020] The tube 2 is preferably made of resin. Examples of resins that can be used for the tube 2 include polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyether polyamide resins, polyurethane resins, polyimide resins, and fluorine-based resins (e.g., PTFE, PFA, ETFE). Among these, polyamide resins, polyimide resins, and fluorine-based resins are preferred, and nylon is particularly preferred from the viewpoints of flexibility and electrical resistance. The outer diameter of the tube 2 can be selected appropriately depending on the therapeutic application, but is preferably approximately 1.5 mm to 3.0 mm.

[0021] The ablation electrode 4 is made of a metal. Examples of metals used for the ablation electrode 4 include copper, gold, platinum, aluminum, iron, and alloys thereof. Among these, from the viewpoints of electrical conductivity and heat transfer, platinum, platinum alloys (e.g., platinum iridium and platinum palladium), and stainless steel are preferably used, and platinum iridium is particularly preferably used.

[0022] The ablation electrode 4 may be provided as a tip (tip electrode) located at the distal end of the tube 2, or as a ring electrode located proximal to the tip. In the drawing, the ablation electrode 4 is provided as a tip 5. The ablation electrode 4 can be attached to the tube 2 by known joining means such as adhesive bonding, welding, or crimping.

[0023] The ablation electrode 4 is connected to the high-frequency power supply 15 via, for example, a conductor, so that the ablation electrode 4 functions as an electrode that cauterizes tissue. The conductor preferably connects the ablation electrode 4 to the high-frequency power supply 15 and is disposed inside the tube 2. Examples of the conductor include iron wire, silver wire, stainless steel wire, copper wire, tungsten wire, nickel-titanium wire, and alloys thereof. The conductor preferably includes a core made of a conductive material, and the core is preferably coated with an insulating material. Examples of insulating materials that can be used include fluorine-based resins (e.g., PTFE, PFA, FEP, ETFE), polyolefin resins (e.g., polyethylene and polypropylene), and polyvinyl chloride resins.

[0024] The shape of the tip 5 of the ablation electrode 4 can be spherical, hemispherical, cylindrical, needle-like, conical, frustum-like, or a combination of these. To prevent damage to blood vessels or the inside of the heart, the distal end of the tip 5 preferably has a smooth shape such as a hemisphere. The size of the tip 5 can be selected appropriately depending on the purpose of treatment, but is preferably approximately 1.5 mm to 3.0 mm.

[0025] In ablation catheter 1, liquid supply unit 14 is disposed proximal to tube 2, and liquid supply lumen 3, which is a flow path for liquid supplied from liquid supply unit 14, is provided inside tube 2. Liquid supply lumen 3 extends in the longitudinal direction within tube 2. By supplying liquid to liquid supply lumen 3, ablation catheter 1 can cool ablation electrode 4, thereby suppressing the occurrence of thrombus in the body cavity due to a rise in the temperature of ablation electrode 4.

[0026] Liquid supply unit 14 is used to supply liquid sent from an external device or the like into ablation catheter 1, specifically into liquid supply lumen 3 of tube 2, and is made of a material containing resin or metal. Liquid supply unit 14 may include a pump for supplying liquid into ablation catheter 1. A syringe, for example, may be used as liquid supply unit 14. Liquid supply unit 14 may also include a cooling unit for cooling the liquid to be supplied.

[0027] A liquid supply lumen 3, which serves as a flow path for the liquid supplied from the liquid supply unit 14, is disposed inside the tube 2. The tube 2 may be provided with only one liquid supply lumen 3 or with multiple liquid supply lumens 3.

[0028] The tube 2 may have either a single-lumen structure with one lumen inside, or a multi-lumen structure with multiple lumens. Alternatively, one lumen may be split into multiple lumens midway. The tube 2 may also have a coaxial structure with multiple coaxial lumens.

[0029] When the tube 2 has a single lumen structure, the lumen of the tube 2 can be used as the liquid supply lumen 3. In this case, since there is no boundary with other lumens inside the tube 2, it is easy to expand and can have many functions.

[0030] When the tube 2 has a multi-lumen structure (including a coaxial structure), any of the lumens present inside the tube 2 can be used as the liquid supply lumen 3. For example, the liquid supply lumen 3 may be a lumen of the tube 2, or may be a lumen of another tube placed inside the tube 2. When the tube 2 has a multi-lumen structure, the expandability is reduced, but specific lumens can be given individual functions, making management easier. For example, a lumen that serves as a liquid flow path and a lumen in which a conductor connecting the ablation electrode 4 and the high-frequency power source 15 is placed can be provided.

[0031] The ablation catheter 1 is provided with a movable body 7 at the distal portion of the tube 2, which is moved by the flow of liquid supplied from the liquid supply unit 14. In the drawings, the movable body 7 is provided with a rotation mechanism that rotates by the flow of liquid supplied from the liquid supply unit 14. By providing the movable body 7 at the distal portion of the tube 2, the liquid flowing within the tube 2 can be agitated by the movable body 7, the flow can be disturbed, or an intentional water flow can be generated. This allows the ablation electrode 4 to be uniformly cooled, effectively suppressing the formation of thrombi in the body cavity due to a rise in the temperature of the ablation electrode 4.

[0032] It is preferable that movable body 7 is capable of stirring the liquid flowing in tube 2, disturbing the flow of the liquid, or generating an intentional water current (e.g., a swirling flow). Movable body 7 is disposed in tube 2 in contact with the liquid supplied from liquid supply unit 14, and is not particularly limited as long as it moves, for example, rotates or moves, due to the flow of the liquid in tube 2. It is preferable that movable body 7 that moves in tube 2 is formed so that movable body 7 remains within a predetermined range in tube 2, for example, by widening a portion of the liquid flow path in tube 2, and movable body 7 is disposed in the widened portion, and movable body 7 remains in the widened portion. Movable body 7 that rotates in tube 2 is provided so as to rotate at a predetermined position in tube 2.

[0033] The movable body 7 can be made of resin or metal. Examples of resin include polyolefin resin (e.g., polyethylene or polypropylene), polyamide resin (e.g., nylon), polyester resin (e.g., PET), aromatic polyether ketone resin (e.g., PEEK), polyether polyamide resin, polycarbonate resin, polyurethane resin, polyimide resin, and fluorine-based resin (e.g., PTFE, PFA, ETFE). Examples of metal include iron, copper, aluminum, gold, platinum, and alloys thereof.

[0034] The movable body 7 is disposed in a distal portion of the tube 2. The distal portion of the tube 2 where the movable body 7 is disposed is preferably, for example, in a range from a position 30 mm proximal to the proximal end of the ablation electrode 4 (if multiple ablation electrodes 4 are provided, the proximal end of the ablation electrode 4 located most proximal) to the distal end of the tube 2, and more preferably in a range from a position 20 mm proximal to the proximal end of the ablation electrode 4 to the distal end of the tube 2. The movable body 7 is preferably disposed at any location in this range in the tube 2.

[0035] The ablation electrode 4 has an internal space, the liquid supply lumen 3 is in communication with the internal space of the ablation electrode 4, and the movable body 7 is preferably disposed somewhere between the liquid supply lumen 3 and the internal space of the ablation electrode 4. When the movable body 7 is disposed in the liquid supply lumen 3, the movable body 7 is preferably disposed within 30 mm, and more preferably within 20 mm, proximal to the proximal end of the ablation electrode 4. By configuring the tube 2 in this manner, the liquid supplied from the liquid supply unit 14 passes through the liquid supply lumen 3 and reaches the internal space of the ablation electrode 4, and the liquid can effectively cool the ablation electrode 4.

[0036] The ablation electrode 4 is preferably a distal tip 5 disposed at the distal end of the tube 2. That is, as the ablation electrode 4, the distal tip 5 is preferably cooled by a liquid supplied from a liquid supply unit 14. In this case, the liquid supply lumen 3 extends from the liquid supply unit 14 to the distal tip 5, and the liquid supplied from the liquid supply unit 14 preferably reaches the internal space of the distal tip 5. By cooling the distal tip 5 with the liquid supplied from the liquid supply unit 14, the occurrence of thrombus in the body cavity can be effectively suppressed. Furthermore, by cooling the distal tip 5, if a ring electrode is provided as the ablation electrode 4 proximal to the distal tip 5, the ring electrode can also be cooled.

[0037] The tip 5 having an internal space can be produced by a method of casting metal into a mold or by cutting the inside of a block of metal.

[0038] In the above case, the movable body 7 is preferably disposed within 30 mm proximal to the internal space of the tip tip 5 or the proximal end of the internal space of the tip tip 5, more preferably within 20 mm proximal to the internal space of the tip tip 5 or the proximal end of the internal space of the tip tip 5, and even more preferably disposed in the internal space of the tip tip 5. This allows the tip tip 5 to be cooled effectively.

[0039] The movable body 7 is preferably a rotation mechanism that rotates at a predetermined position in the distal portion of the tube 2 due to the flow of liquid supplied from the liquid supply unit 14. By providing a rotation mechanism as the movable body 7, the liquid flowing inside the tube 2 is forcibly stirred by the rotation mechanism, allowing for more uniform cooling of the ablation electrode 4 disposed in the distal portion of the tube 2. The ablation catheter 1 is configured such that the rotation mechanism is rotated by the liquid supplied through the liquid supply lumen 3 and does not require a power source to rotate the rotation mechanism, allowing the tube 2 to be made thinner and more flexible. The flow rate of the liquid flowing through the liquid supply lumen 3 inside the thin tube 2 is limited, and it is preferable that the rotation mechanism be configured to rotate even with a small flow rate.

[0040] The rotation mechanism includes a rotating unit 8 and is rotatable around a rotation axis. The rotation axis is located at the rotation center of the rotation mechanism. The rotating unit 8 has blades 9, which can agitate the liquid flowing inside the tube 2. The blades 9 are preferably formed in the shape of plates extending radially from the rotation axis, and the plates may be formed in either a flat or curved shape. It is preferable that a plurality of blades 9 are provided on the rotating unit 8, and for example, it is preferable that one rotating unit 8 is provided with 2 to 12 blades 9.

[0041] Rotating unit 8 may or may not have shaft portion 10 at the position that becomes the rotation axis. In the former case, blade portions 9 are preferably provided so as to extend radially from shaft portion 10. In the latter case, for example, rotating unit 8 preferably has a cylindrical portion, and blade portions 9 are preferably provided so as to extend inward (toward the rotation axis) from the inner surface of the cylindrical portion. Note that rotating unit 8 may have shaft portion 10 and a cylindrical portion, and blade portions 9 may be provided so as to connect shaft portion 10 to the inner surface of the cylindrical portion.

[0042] The blades 9 may be arranged parallel to, perpendicular to, or oblique to the extension direction of the rotation shaft of the rotating unit 8. The arrangement of the blades 9 relative to the rotation shaft is determined based on the extension direction of the cross-sectional shape of the blades 9 on the rotation shaft side. It is preferable that the arrangement of the blades 9 relative to the rotation shaft be appropriately set based on the rotation direction of the rotating unit 8.

[0043] In one embodiment, it is preferable that the blades 9 have a certain angle with respect to the rotation axis. In other words, it is preferable that the blades 9 are arranged obliquely with respect to the extension direction of the rotation axis. By providing the blades 9 in this manner, it is possible to efficiently agitate the liquid flowing inside the tube 2. It is preferable that the blades 9 are arranged at an angle of, for example, 30° to 75° with respect to the extension direction of the rotation axis.

[0044] Specific forms or shapes of the rotating part 8 include an impeller, a water wheel, a gear, a screw shape, etc. The blades 9 of the rotating part 8 preferably have a depression in each to more easily receive the liquid. The depression is preferably spoon-shaped. This makes it easier for the rotating mechanism to rotate with a small flow rate.

[0045] Rotating unit 8 of the rotation mechanism can be made of resin or metal. For the resin or metal that makes up rotating unit 8, see the explanation of the constituent materials of movable body 7 above. Among them, examples of resin include synthetic resins such as polycarbonate, polyethylene, and silicone, and examples of metal include platinum alloy, stainless steel, and platinum-palladium.

[0046] The rotation mechanism is disposed somewhere between the liquid supply lumen 3 and the internal space of the ablation electrode 4. The rotation mechanism may be provided so that its rotation axis is perpendicular to the longitudinal direction of the tube 2, so that its rotation axis extends parallel to the longitudinal direction of the tube 2, or so that its rotation axis extends obliquely relative to the longitudinal direction of the tube 2. Note that, in order to facilitate the installation of the rotating unit 8, which serves as the rotation mechanism, inside the tube 2, it is preferable that the rotation axis of the rotation mechanism extend perpendicular to or parallel to the longitudinal direction of the tube 2.

[0047] Rotating unit 8 of the rotation mechanism may have shaft 10 attached to the inner wall of liquid supply lumen 3 or the inner wall of ablation electrode 4, or a shaft support member supporting shaft 10 may be disposed inside liquid supply lumen 3 or ablation electrode 4. When rotating unit 8 of the rotation mechanism has a cylindrical portion and blades 9 are formed to extend inward from the inner surface of the cylindrical portion, rotating unit 8 may be disposed in a free state inside liquid supply lumen 3 or ablation electrode 4. For example, an expanded diameter portion may be provided inside liquid supply lumen 3 or ablation electrode 4, and rotating unit 8 having a cylindrical portion may be rotatably fitted into the expanded diameter portion.

[0048] The rotating part 8 of the rotation mechanism is preferably located within the internal space of the distal tip 5 or within 30 mm proximal to the proximal end of the internal space of the distal tip 5, more preferably within 20 mm proximal to the internal space of the distal tip 5 or within the proximal end of the internal space of the distal tip 5, and even more preferably located in the internal space of the distal tip 5. When the rotating part 8 is located in the internal space of the distal tip 5, it is preferably located in the internal space of the distal tip 5, near the distal end of the liquid supply lumen 3. By installing a liquid rotation mechanism such as a water wheel in such a location, a deliberate water flow can be generated, allowing for efficient liquid replacement in the distal tip 5. This allows the distal tip 5 to be uniformly cooled, thereby suppressing the occurrence of thrombus formation.

[0049] 2, the ablation electrode 4 can have a hole 6 through which the liquid supplied from the liquid supply unit 14 is discharged. In this case, the ablation catheter 1 is endowed with an irrigation function, and the liquid supplied from the liquid supply unit 14 cools the ablation electrode 4 and then is discharged from the hole 6 to the outside of the tube 2, thereby enabling the ablation electrode 4 to be efficiently cooled.

[0050] The holes 6 can be provided anywhere on the ablation electrode 4, but are preferably provided on the side or tip of the ablation electrode 4. In particular, it is preferable that the distal tip 5 of the ablation electrode 4 is cooled by liquid supplied from the liquid supply unit 14, and that the holes 6 be provided on the side or tip of the distal tip 5.

[0051] 2 and 3, in the above embodiment, the rotation axis of the rotation mechanism preferably extends parallel to the longitudinal direction of the tube 2. This allows the liquid supplied to the inside of the ablation electrode 4 to be efficiently agitated by the rotation mechanism, and the ablation electrode 4 can be cooled more uniformly.

[0052] In another embodiment, as shown in FIG. 4 , the ablation catheter 1 can further include a liquid return lumen 11 disposed inside the tube 2, which serves as a flow path for returning the liquid supplied to the internal space of the ablation electrode 4 to the proximal side of the tube 2. In this case, the ablation electrode 4 does not have a hole 6, and the tube 2 is an occluded type with a closed distal portion. The liquid supplied from the liquid supply unit 14 to the liquid supply lumen 3 circulates in the distal portion of the tube 2, thereby uniformly cooling the internal space of the ablation electrode 4. In this case, the liquid supply unit 14 disposed on the proximal side of the tube 2 may include a recovery unit that recovers the liquid returned through the liquid return lumen 11, or a circulation unit that circulates the liquid between the liquid supply unit 14 and the distal portion of the tube 2.

[0053] In the above embodiment, as shown in Figure 4, the rotation axis of the rotation mechanism is preferably perpendicular to the longitudinal direction of the tube 2. This allows the liquid supplied from the liquid supply lumen 3 to be smoothly returned to the liquid return lumen 11. In this case, the rotating unit 8 of the rotation mechanism is preferably disposed in the internal space of the distal tip 5. Since the rotation axis is disposed in a direction perpendicular to the longitudinal direction of the tube 2, the rotating unit 8 is preferably disposed within the distal tip 5 so that the rotation axis is parallel to the cross-sectional direction of the longitudinal axis of the tube 2. The rotating unit 8 is preferably disposed near the distal end of the liquid supply lumen 3.

[0054] In the embodiment shown in Fig. 4, tube 2 has a double lumen structure, one of which serves as liquid supply lumen 3 and the other as liquid return lumen 11. In the embodiment shown in Fig. 4, it is preferable that the inner diameter of liquid supply lumen 3 is smaller than the inner diameter of liquid return lumen 11, since this makes it easier to rotate the rotation mechanism with a small amount of liquid.

[0055] As shown in Figure 5, the tube 2 can have a coaxial structure, an inner tube 12 can be placed inside the tube 2, the lumen of the inner tube 12 can be used as the liquid supply lumen 3, and the space between the tube 2 and the inner tube 12 can be used as the liquid return lumen 11.

[0056] 5, a rotation mechanism is preferably provided inside inner tube 12 (i.e., liquid supply lumen 3) or on its distal side. The rotation axis of the rotation mechanism preferably extends parallel to the longitudinal direction of tube 2, and when viewed from the distal side of tube 2, rotating part 8 is preferably formed to be radially smaller than the inner diameter of tube 2, and more preferably formed to be radially smaller than the outer diameter of inner tube 12. This allows the liquid supplied from liquid supply lumen 3, which is the lumen of inner tube 12, to be smoothly returned to liquid return lumen 11, which is the space between tube 2 and inner tube 12.

[0057] FIG. 6 shows an example in which an inner tube 13 is disposed as a separate tube inside the liquid supply lumen 3 of the tube 2 in the configuration shown in FIG. 4. That is, the tube 2 has a double lumen structure, one of which has a coaxial structure. A conductor, for example, connecting the ablation electrode 4 to the high-frequency power source 15, can be disposed in the inner tube 13. This improves the insulation between the inside and outside of the inner tube 13. For example, this can prevent electricity from flowing through the liquid supplied from the liquid supply unit 14, thereby improving the insulation of the catheter 1. In this case, the inner tube 13 is preferably made of an insulating or electrically resistant resin such as polyamide resin (e.g., nylon), fluorine-based resin, or polyimide resin. From the viewpoint of insulation, the inner tube 13 is more preferably made of polyimide.

[0058] Although not shown in the drawings, in the embodiment shown in Fig. 4, another tube can also be placed inside the liquid return lumen 11 of the tube 2. In the embodiment shown in Fig. 2, another tube can also be placed inside the liquid supply lumen 3. Furthermore, in the embodiment shown in Fig. 5, another tube can also be placed inside the liquid supply lumen 3 or the liquid return lumen 11. [Explanation of symbols]

[0059] 1. Ablation catheter 2. Tube 3. Liquid supply lumen 4. Ablation Electrodes 5. Tip 6. Hole 7. Movable body 8. Rotating part 9. Blade section 10. Shaft 11. Liquid return lumen 12.Inner tube 13.Inner tube 14.Liquid supply section 15.High frequency power supply

Claims

1. a tube having a distal end and a proximal end; a liquid supply disposed proximal to the tube; a liquid supply lumen disposed inside the tube and serving as a flow path for liquid supplied from the liquid supply unit; an ablation electrode disposed in a distal portion of the tube and supplied with a high-frequency current from a high-frequency power source; a movable body disposed in a distal portion of the tube and moved by the flow of liquid supplied from the liquid supply portion; The ablation electrode has an internal space and a hole on a side surface or a tip thereof, the fluid supply lumen communicates with the interior space of the ablation electrode; The movable body is an ablation catheter disposed in the internal space of the ablation electrode.

2. a tube having a distal end and a proximal end; a liquid supply disposed proximal to the tube; a liquid supply lumen disposed inside the tube and serving as a flow path for liquid supplied from the liquid supply unit; an ablation electrode disposed in a distal portion of the tube and supplied with a high-frequency current from a high-frequency power source; a movable body that is a rotation mechanism that is disposed in a distal portion of the tube and rotates by the flow of liquid supplied from the liquid supply portion, the ablation electrode has an interior space; the fluid supply lumen communicates with the interior space of the ablation electrode; the movable body is disposed at a location ranging from the liquid supply lumen to the internal space of the ablation electrode, An ablation catheter in which the rotation axis of the rotation mechanism is perpendicular to the longitudinal direction of the tube.

3. The ablation catheter according to claim 2 , wherein the movable body is disposed in the internal space of the ablation electrode.

4. The ablation catheter according to claim 2 or 3, wherein the ablation electrode has a hole on a side surface or a tip.

5. The ablation catheter according to claim 1 , wherein the movable body is a rotation mechanism that rotates due to the flow of liquid supplied from the liquid supply unit.

6. An ablation catheter as described in Claim 5, wherein the rotation axis of the rotation mechanism extends parallel to the longitudinal direction of the tube.

7. An ablation catheter described in any one of claims 2 to 6, wherein the rotating part of the rotation mechanism is in the shape of an impeller, a water wheel, a gear, or a screw.

8. An ablation catheter described in any one of claims 2 to 7, wherein the rotating part of the rotating mechanism has a blade part, and the blade part has a recess for receiving liquid.

9. An ablation catheter described in any one of claims 2 to 8, wherein the rotating part of the rotating mechanism has a blade part, and the blade part is arranged obliquely with respect to the extension direction of the rotation axis of the rotating part.

10. The ablation catheter according to any one of claims 1 to 9, wherein the ablation electrode is a tip disposed at the distal end of the tube.

11. The ablation catheter according to any one of claims 1 to 10, further comprising a liquid return lumen disposed inside the tube and serving as a flow path for returning the liquid supplied to the internal space of the ablation electrode to the proximal side of the tube.

12. The ablation catheter according to any one of claims 1 to 11, wherein an inner tube is disposed inside the liquid supply lumen.

13. The high frequency power source is disposed proximal to the tube; The ablation catheter according to claim 12, wherein a conductor connecting the ablation electrode and the high-frequency power source is disposed inside the inner tube.

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