Electrode catheter

Abstract

To provide an electrode catheter with improved pushability that allows a side hole for passing a lead wire to be formed easily, and can prevent deterioration of strength of a section where the side hole is formed.SOLUTION: An electrode catheter includes: an outer tube 20; an inner tube 30 extending in a lumen 20a of the outer tube 20; a plurality of electrodes 40 arranged separated in a longitudinal axis direction x on an outside surface of a distal part of the outer tube 20; and a plurality of lead wires 50 extending in the lumen 20a of the outer tube 20 and outside the inner tube 30, which are connected to the plurality of electrodes 40 respectively. The inner tube 30 includes a wire 35 in an electrode arrangement section 40D from a proximal end of the most proximal electrode 41 to a distal end of the most distal electrode 42. The outer tube 20 includes a metal wire 25 more on a proximal side than a proximal end of the electrode arrangement section 40D, and does not include the metal wire 25 from the proximal end to the distal side of the electrode arrangement section 40D.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to electrode catheters. [Background technology]

[0002] Catheters with electrodes are sometimes used in the examination and treatment of arrhythmias such as atrial fibrillation. During examinations, electrode catheters are inserted into the cardiac chambers to measure intracardiac potentials and identify abnormal areas of the heart that are causing the arrhythmia. During treatment, electrode catheters are used in ablation surgery, in which a high-frequency current is passed from the catheter electrode to the myocardium causing the arrhythmia, cauterizing the source of the arrhythmia and electrically isolating it from the heart, and in defibrillation treatment, in which an electrical signal is sent from the catheter electrode to the heart when atrial fibrillation occurs.

[0003] For example, Patent Document 1 discloses an electrode catheter comprising a catheter shaft, a ring electrode, and a conducting wire connected to the ring electrode, the catheter shaft being a braided tube reinforced with braiding over its entire length, and the braid reinforcing at least the tip portion of the catheter shaft being made of resin. The electrode catheter of Patent Document 1 attempts to improve torque transmission by using a braided tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 145503 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional electrode catheters, it is necessary to form a side hole in the catheter shaft to pass the conducting wire connected to the electrode. However, because the catheter shaft is a braided tube reinforced by braiding over its entire length, there was a problem that it was not easy to form the side hole.

[0006] In view of the above circumstances, an object of the present invention is to provide an electrode catheter in which it is easy to form side holes for passing conductors through, which prevents a decrease in strength in the section in which the side holes are formed, and which has improved pushability. [Means for solving the problem]

[0007] An electrode catheter according to an embodiment of the present invention that can solve the above problems is as follows. [1] An electrode catheter having a longitudinal axis direction and a radial direction perpendicular to the longitudinal axis direction, and having a distal end and a proximal end in the longitudinal axis direction, the electrode catheter comprising: an outer tube having an inner lumen extending in the longitudinal axis direction; an inner tube extending into the inner lumen of the outer tube; a plurality of electrodes arranged at a distance in the longitudinal axis direction on the outer surface of the distal part of the outer tube; and a plurality of conductors extending in the inner lumen of the outer tube to the outside of the inner tube and connected to the plurality of electrodes, respectively. The inner tube has a wire in an electrode arrangement section from a proximal end of a most proximal electrode arranged most proximally among the plurality of electrodes in the longitudinal axis direction to a distal end of a most distal electrode arranged most distally among the plurality of electrodes. The outer tube has a metal wire proximal to the proximal end of the electrode arrangement section, and does not have the metal wire distal to the proximal end of the electrode arrangement section.

[0008] In the above electrode catheter, since the outer tube does not have a metal wire from the proximal end to the distal side of the electrode arrangement section, it is easy to form a side hole in the outer tube for passing a conductor connected to the electrode arranged on the outer surface of the outer tube. Furthermore, even if the outer tube does not have a metal wire from the proximal end to the distal side of the electrode arrangement section, since the inner tube has a wire in the electrode arrangement section, it is possible to prevent a decrease in strength of the section in which the side hole is formed. Furthermore, since the outer tube has a metal wire on the proximal side of the proximal end of the electrode arrangement section, it is possible to provide an electrode catheter with improved pushability.

[0009] The electrode catheter according to the embodiment of the present invention is preferably any one of the following items [2] to [6]. [2] An electrode catheter as described in [1], wherein, in the longitudinal axis direction, the inner tube does not have the metal wire proximal to the distal end of the metal wire of the outer tube. [3] An electrode catheter as described in [1] or [2], wherein, in the longitudinal axis direction, the proximal end of the wire of the inner tube and the distal end of the metal wire of the outer tube are at the same position, or the proximal end of the wire of the inner tube is located distal to the distal end of the metal wire of the outer tube. [4] An electrode catheter according to any one of [1] to [3], wherein in the longitudinal axis direction, the distal end of the wire of the inner tube is located proximal to the distal end of the inner tube. [5] An electrode catheter described in any one of [1] to [4], wherein the metal wire of the outer tube is at least one of a coil wound in a spiral shape and a braid woven in a mesh pattern. [6] An electrode catheter described in any one of [1] to [5], wherein the wire of the inner tube is at least one of a spirally wound coil and a braid woven in a mesh pattern. Effect of the Invention

[0010] According to the electrode catheter described above, it is easy to form side holes for passing conductors therethrough, and it is possible to prevent a decrease in strength of the section in which the side holes are formed, and also to improve pushability. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of an electrode catheter according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of the electrode catheter shown in FIG. 1 when the distal portion is curved. [Diagram 3] 2 is a longitudinal cross-sectional view of the distal portion of the electrode catheter shown in FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view showing a modification of FIG. [Diagram 5] FIG. 4 is a VV cross-sectional view of the electrode catheter shown in FIG. 3. [Figure 6] 6 is a cross-sectional view of the electrode catheter shown in FIG. 3 taken along the line VI-VI. [Figure 7] 7 is a cross-sectional view taken along line VII-VII of the electrode catheter shown in FIG. 3. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII of the electrode catheter shown in FIG. [Figure 9] 13 is a longitudinal cross-sectional view of a distal portion of an electrode catheter according to another embodiment of the present invention. FIG. [Figure 10] 10 is a cross-sectional view of the electrode catheter shown in FIG. 9 taken along the line XX. [Figure 11] FIG. 4 is a diagram illustrating the coil pitch. [Figure 12] FIG. 4 is a diagram illustrating the pitch of the blades. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described below based on the embodiments, but the present invention is not limited to the following embodiments, and can be modified as appropriate within the scope of the above and below, and all of these are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, the specification and other drawings should be referred to. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, since priority is given to helping understand the features of the present invention.

[0013] An electrode catheter according to an embodiment of the present invention will be described with reference to Figs. 1 to 12. Fig. 1 is a side view of an electrode catheter according to an embodiment of the present invention. Fig. 2 is a side view of the electrode catheter shown in Fig. 1 when the distal part is curved. Fig. 3 is a longitudinal cross-sectional view of the distal part of the electrode catheter shown in Fig. 1, and Fig. 4 is a cross-sectional view showing a modified example of Fig. 3. Figs. 5 to 8 are VV cross-sectional views, VI-VI cross-sectional views, VII-VII cross-sectional views, and VIII-VIII cross-sectional views of the distal part of the electrode catheter shown in Fig. 3, respectively. Fig. 9 is a longitudinal cross-sectional view of the distal part of the electrode catheter according to another embodiment of the present invention. Fig. 10 is a XX cross-sectional view of the electrode catheter shown in Fig. 9. Fig. 11 is a diagram for explaining the pitch of the coil, and Fig. 12 is a diagram for explaining the pitch of the blade. The hatching in Fig. 12 does not represent a cross section, but represents one of the multiple wires constituting the blade.

[0014] 1, the electrode catheter 10 has a longitudinal direction x which is the extension direction of the outer tube 20, a radial direction y which is perpendicular to the longitudinal direction x and extends radially from the central axis of the outer tube 20, and a circumferential direction z which is a direction along the outer periphery of the outer tube 20, and has a distal end and a proximal end in the longitudinal direction x. In this specification, the direction toward the user's hand in the longitudinal direction x is referred to as the proximal side, and the side opposite to the proximal side, i.e., the direction toward the subject of treatment, is referred to as the distal side.

[0015] The components and parts of the electrode catheter 10 each have a longitudinal axis direction, a radial direction, and a circumferential direction, which may be the same as or different from the longitudinal axis direction x, radial direction y, and circumferential direction z of the electrode catheter 10; however, for ease of understanding, this specification describes all components and parts as having the same longitudinal axis direction, radial direction, and circumferential direction as the longitudinal axis direction x, radial direction y, and circumferential direction z of the electrode catheter 10.

[0016] As shown in Fig. 2, the distal portion of the electrode catheter 10 is preferably bendable. The distal portion of the electrode catheter 10 may be bendable by pulling a wire fixed to the distal end of the electrode catheter 10 from the proximal side, or may be naturally bent by giving a bending tendency to the distal portion of the electrode catheter 10 before use. The bendable distal portion of the electrode catheter 10 makes it easier to follow the curvature of blood vessels and the inside of the heart, improving insertion ease and improving the effect of preventing damage to the body cavity wall.

[0017] As shown in FIG. 2, when the distal portion of the electrode catheter 10 is curved, the longitudinal axis direction x is curved along the extension direction of the electrode catheter 10, and a radial direction y and a circumferential direction z are defined at each position of the longitudinal axis direction x.

[0018] As shown in Figs. 1 and 2, a handle 60 may be connected to the proximal side of the outer tube 20. A user can easily operate the electrode catheter 10 by gripping the handle 60. A guidewire tube 61 through which a guidewire is inserted and a guidewire port 62 serving as an insertion port for the guidewire may be provided on the proximal side of the handle 60. In addition, it is preferable that a conductor tube 51 is provided on the proximal side of the handle 60, and a conductor 50 described later is connected to a connector 52 through the conductor tube 51. The connector 52 is connected to an external device such as a power source or an electrocardiograph, so that the conductor 50 can electrically connect the external device and the electrode 40.

[0019] 3, the electrode catheter 10 has an outer tube 20 having a lumen 20a extending in the longitudinal direction x, and an inner tube 30 extending into the lumen 20a of the outer tube 20. By disposing the inner tube 30 in the lumen 20a of the outer tube 20, a double-tube structure can be formed, and various functions can be imparted to the electrode catheter 10 by disposing a lead wire 50 connected to an electrode 40 (described later) or an internal structure for bending the distal portion of the electrode catheter 10 in the space inside the outer tube 20 and outside the inner tube 30 in the radial direction y, or by disposing a member such as a guidewire in the lumen 30a of the inner tube 30.

[0020] When a guidewire is used, the guidewire may be placed in the lumen 30a of the inner tube 30, and the tip of the guidewire may reach the site to be treated first, and then the electrode catheter 10 may be delivered along the guidewire to the site to be treated, or the electrode catheter 10 may be delivered first to the vicinity of the site to be treated, and then the tip of the guidewire may be delivered to the site to be treated, and the distal end of the electrode catheter 10 may be positioned. The guidewire is preferably introduced into the lumen 30a of the inner tube 30 from a guidewire port 62 provided on the electrode catheter 10 through a guidewire tube 61.

[0021] When the electrode catheter 10 is used for examination or treatment, the electrode catheter 10 is inserted into a body cavity from the distal end side of the outer tube 20 and the inner tube 30, and the distal end of the electrode catheter 10 is delivered to the treatment site by operating the handle 60, etc. For this reason, the outer tube 20 and the inner tube 30 are preferably flexible, and the outer tube 20 and the inner tube 30 preferably have a resin tube as a component.

[0022] Specific examples of resins constituting the resin tubes that are components of the outer tube 20 and the inner tube 30 include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, polyimide resins, aromatic polyether ketones such as PEEK, polyether polyamide resins, polyurethane resins, fluorine resins such as PTFE, PFA, ETFE, vinyl chloride resins, silicone resins, and other synthetic resins and natural rubber. These may be used alone or in combination of two or more.

[0023] The resin tube constituting the outer tube 20 may have a single-layer structure or a multi-layer structure in which a plurality of layers are laminated. Among these, it is preferable that the outer tube 20 has a multi-layer structure. In the case of a multi-layer structure, for example, the outer layer is made of a polyamide resin or a polyether polyamide resin, and the inner layer is made of a fluorine-based resin having high slipperiness, and each layer can be given a desired function, such as increasing the sliding property of members such as the conductor 50 arranged in the inner cavity 20a of the outer tube 20.

[0024] The resin tube constituting the inner tube 30 may have a single-layer structure or a multi-layer structure in which a plurality of layers are laminated. Among these, it is preferable that the inner tube 30 has a multi-layer structure. In the case of a multi-layer structure, for example, the outer layer is made of a polyamide resin or a polyether polyamide resin, and the inner layer is made of a fluorine-based resin having high slipperiness, and each layer can be given a desired function, such as increasing the sliding property of a member such as a guide wire placed in the lumen 30a of the inner tube 30.

[0025] The length in the longitudinal direction x of the outer tube 20 and the inner tube 30 can be selected to be an appropriate length for treatment. For example, the length in the longitudinal direction x of the outer tube 20 and the inner tube 30 can be 400 mm or more and 2000 mm or less. The length in the longitudinal direction x of the outer tube 20 and the inner tube 30 should be relatively long when the tip of the electrode catheter 10 is inserted from a lower limb vein and delivered to the heart, and may be relatively short when the tip of the electrode catheter 10 is inserted from a subclavian vein or a jugular vein and delivered to the heart.

[0026] The outer diameter of the outer tube 20 is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 1 mm or more. By setting the lower limit of the outer diameter of the outer tube 20 within the above range, the outer tube 20 can be given an appropriate rigidity, and the electrode catheter 10 can be made to have high insertability into blood vessels. Moreover, the outer diameter of the outer tube 20 is preferably 3 mm or less, more preferably 2.8 mm or less, even more preferably 2.5 mm or less, and particularly preferably 2.0 mm or less. By setting the upper limit of the outer diameter of the outer tube 20 within the above range, the outer diameter of the electrode catheter 10 can be prevented from becoming too large, and low invasiveness can be improved. Furthermore, the outer diameter of the outer tube 20 may be 1.8 mm or less, 1.7 mm or less, 1.5 mm or less, 1.0 mm or less, or 0.8 mm or less. This allows the electrode catheter 10 to be used as a microcatheter with a small outer diameter at the distal end, and the distal end of the electrode catheter 10 can be delivered to the periphery of the coronary sinus.

[0027] The thickness of the outer tube 20, i.e., the thickness of the side wall of the outer tube 20, is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. By setting the lower limit of the thickness of the outer tube 20 within the above range, it is possible to increase the rigidity of the outer tube 20 and provide an electrode catheter 10 with good insertability into a blood vessel. Moreover, the thickness of the outer tube 20 is preferably 350 μm or less, more preferably 300 μm or less, and even more preferably 250 μm or less. By setting the upper limit of the thickness of the outer tube 20 within the above range, the lumen 20a of the outer tube 20 can be widened, which makes it easier to arrange the inner tube 30 and allows the electrodes to be multipolarized.

[0028] The outer diameter of the inner tube 30 is not particularly limited as long as the inner tube 30 can be placed in the lumen 20a of the outer tube 20, but is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. By setting the lower limit of the inner tube 30 within the above range, the inner tube 30 can be given appropriate rigidity, and the electrode catheter 10 can be made to have high insertability into blood vessels. Furthermore, the outer diameter of the inner tube 30 is preferably 2.8 mm or less, more preferably 2.5 mm or less, even more preferably 2.0 mm or less, and particularly preferably 1.8 mm or less. By setting the upper limit of the outer diameter of the inner tube 30 within the above range, the inner tube 30 can be easily placed in the lumen 20a of the outer tube 20. Furthermore, the outer diameter of the inner tube 30 may be 1.6 mm or less, 1.5 mm or less, 1.2 mm or less, 1.0 mm or less, 0.8 mm or less, or 0.6 mm or less when the outer diameter of the outer tube 20 is small.

[0029] The thickness of the inner tube 30 , i.e., the thickness of the side wall of the inner tube 30 , may be equal to the thickness of the outer tube 20 or may be thinner than the thickness of the outer tube 20 .

[0030] As shown in Figs. 1 to 3, the electrode catheter 10 has a plurality of electrodes 40 arranged at intervals in the longitudinal axis direction x on the outer surface of the distal portion of the outer tube 20. The electrodes 40 can be used to measure cardiac potential to diagnose arrhythmia, or to apply a high-frequency current to the electrodes 40 to cauterize body tissue in order to treat arrhythmia. The electrode catheter 10 can also be used as a defibrillation catheter. In this case, it is preferable to arrange the electrodes 40 as an electrode group, and to provide an electrical signal to the heart from the electrode group when atrial fibrillation occurs.

[0031] 3, the electrode 40 is preferably disposed on the outside of a side hole 21 formed so as to penetrate the side wall of the distal portion of the outer tube 20. At least one side hole 21 is preferably formed for each electrode 40. The electrode 40 can function as a measurement electrode or a reference electrode when measuring potential, and also as an electrode for passing a high-frequency current or an electrode for applying an electrical signal.

[0032] The method of forming the side hole 21 for passing the conductive wire 50 through the side wall of the outer tube 20 is not particularly limited, but examples include a method of piercing the side wall of the outer tube 20 with a sharp rod-shaped member such as a needle or an awl, or a method of irradiating the side wall with laser light.

[0033] The electrode 40 may be a ring-shaped electrode as shown in Figs. 3 to 5, or may have a cross section with a cut in the ring that is C-shaped, or may have a coil shape with a wound wire. When the electrode 40 has such a shape, the electrode 40 can be arranged on the outer surface of the outer tube 20 by crimping the electrode 40 to the outer tube 20. Alternatively, the electrode 40 may be a plate electrode formed independently in an island shape when viewed from the outside of the outer tube 20. The shape of the plate electrode may be any shape such as a polygonal shape such as a rectangle or a square, or a circular shape. It is preferable that at least one of the inner surface and the outer surface of such a plate electrode is curved so as to easily follow the curved surface of the outer tube 20. Among them, the electrode 40 is preferably ring-shaped. By the electrode 40 being ring-shaped, the area of ​​the electrode 40 on the outer peripheral surface of the outer tube 20 can be increased, and the electrode 40 can be easily brought into contact with a target tissue such as the inner wall of the heart.

[0034] When the electrode 40 has a shape having a diameter such as a ring shape, a C-shape, or a coil shape, the inner diameter of the electrode 40 is preferably smaller than the maximum outer diameter of the outer tube 20. This makes it difficult for the end of the electrode 40 to get caught on other objects, improving insertion properties and making it difficult to damage the body cavity wall such as the inner wall of the heart or blood vessel. To make the inner diameter of the electrode 40 smaller than the maximum outer diameter of the outer tube 20, for example, there can be mentioned a method of forming the inner diameter of the electrode 40 larger than the maximum outer diameter of the outer tube 20, disposing the electrode 40 on the outside of the outer tube 20 and crimping the electrode 40 from the outside to reduce the inner diameter of the electrode 40, or a method of forming the outer tube 20 having an outer diameter smaller than the inner diameter of the electrode 40 from a thermally expandable resin, disposing the electrode 40 on the outside of the outer tube 20 and heating the outer tube 20 to increase the maximum outer diameter of the outer tube 20.

[0035] A recess for disposing the electrode 40 is preferably formed on the radially outward side of the side hole 21 of the outer tube 20. This allows the electrode 40 to be disposed in the recess, which prevents the electrode 40 from protruding outward in the radial direction y and prevents the electrode 40 from getting caught on a body cavity wall such as the inner wall of a blood vessel or the heart, reducing insertion ability or damaging the body cavity wall. There are no particular limitations on the method for forming the recess in the side wall of the outer tube 20, but examples include cutting with a drill or the like, applying pressure with a rod-shaped object, thermal processing in which a heated rod-shaped object is pressed against the body cavity wall, and irradiation with laser light.

[0036] The electrode 40 may be made of any material as long as it is conductive, and may be made of a metal or a mixture containing a metal and a resin. In particular, metals such as platinum, platinum-iridium alloy, stainless steel, and tungsten, or conductive resins are preferably used as the material for the electrode 40. When the electrode 40 is made of conductive resin, it is preferable to mix a contrast agent such as barium sulfate or bismuth oxide into the electrode 40 so that the electrode 40 can be viewed under X-ray fluoroscopy.

[0037] 3, the electrode catheter 10 has a proximal-most electrode 41 that is disposed most proximal among the multiple electrodes 40 in the longitudinal axis direction x, and a distal-most electrode 42 that is disposed most distal among the multiple electrodes 40. The number of electrodes 40 is not particularly limited, and may be, for example, 2 or more, 3 or more, 5 or more, 8 or more, 10 or more, 15 or more, 50 or less, 40 or less, 30 or less, 25 or less, 20 or less, etc. Depending on the purpose of using the electrode catheter 10, the multiple electrodes 40 may form an electrode group, and the multiple electrode groups may be disposed at a distance from each other in the longitudinal axis direction x.

[0038] The size of each of the multiple electrodes 40 may be the same or different. The different sizes of the electrodes 40 refer to, for example, that the lengths of the electrodes 40 in the longitudinal axis direction x are different.

[0039] As shown in FIG. 3, the electrode catheter 10 has a plurality of conductors 50 that extend through the lumen 20a of the outer tube 20 and outside the inner tube 30, and are connected to the plurality of electrodes 40, respectively. The conductors 50 are connected to the inner surfaces of the electrodes 40, and preferably extend through the side holes 21 formed in the outer tube 20 to the lumen 20a of the outer tube 20 outside the inner tube 30. The conductors 50 preferably extend proximally from the proximal end of the lumen 20a of the outer tube 20 and are preferably connected to a connector 52 through a conductor tube 51. The connector 52 is connected to an external device such as a power source or an electrocardiograph, so that the conductors 50 can electrically connect the electrodes 40 to the external device. It is preferable that one conductor 50 is connected to each of the plurality of electrodes 40.

[0040] The conductor wire 50 may be any wire that is electrically conductive, and may be, for example, a copper wire, an iron wire, a stainless steel wire, a piano wire, a tungsten wire, a nickel-titanium alloy wire, etc. Among these, a stainless steel wire is particularly preferred because it has linearity and rigidity, making it easy to pass the conductor wire 50 through the side hole 21 of the outer tube 20, and because the connection between the conductor wire 50 and the electrode 40 is less likely to break.

[0041] Each conductor 50 may be a solid wire or a stranded wire. The cross-sectional shape of each conductor 50 perpendicular to the longitudinal axis direction x may be, for example, a circle, an ellipse, a polygon, or a combination of these. The major axis of the conductor 50 is not particularly limited, and is preferably 0.05 mm or more, more preferably 0.08 mm or more, even more preferably 0.1 mm or more, and is preferably 0.3 mm or less, more preferably 0.2 mm or less, and even more preferably 0.15 mm or less. The major axis of the conductor 50 means the diameter of the circumscribing circle of the conductor 50 in the cross-section perpendicular to the longitudinal axis direction x, regardless of whether the conductor 50 is a solid wire or a stranded wire, and regardless of the cross-sectional shape.

[0042] The conductor 50 may have a coating material on a portion other than the end connected to the electrode 40. This can prevent short-circuiting with adjacent members. The material for the coating of the conductor 50 may be an insulating material, and examples of the material include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon, polyester resins such as PET, aromatic polyether ketone resins such as PEEK, polyether polyamide resins, polyurethane resins, polyimide resins, fluororesins such as PTFE, PFA, and ETFE, and synthetic resins such as polyvinyl chloride resins. Among these, fluororesins are preferred, and PFA is more preferred. Since the covering material of the conductor 50 is a fluororesin, the insulation properties of the conductor 50 are enhanced and the sliding properties against other components in the inner cavity 20a of the outer tube 20, such as the conductor 50 connected to other electrodes 40, the inner wall of the outer tube 20, the outer wall of the inner tube 30, and the wire 35 described later when exposed on the outer wall of the inner tube 30, are improved. This prevents damage to the covering material of the conductor 50 due to contact with other parts, and improves the protective effect of the covering material on the conductor 50.

[0043] The conductive wire 50 and the electrode 40 can be connected by a method such as laser welding, resistance welding, adhesion with an adhesive, etc. The conductive wire 50 may be directly connected to the electrode 40, or may be indirectly connected to the electrode 40 via a conductive member having electrical conductivity between the conductive wire 50 and the electrode 40 (not shown).

[0044] As shown in FIG. 3, the inner tube 30 has a wire 35 in an electrode arrangement section 40D from the proximal end of the most proximal electrode 41, which is arranged most proximally among the multiple electrodes 40 in the longitudinal axis direction x, to the distal end of the most distal electrode 42, which is arranged most distally among the multiple electrodes 40, and the outer tube 20 has a metal wire 25 proximal to the proximal end of the electrode arrangement section 40D and does not have a metal wire 25 distal from the proximal end of the electrode arrangement section 40D.

[0045] The metal wire 25 that the outer tube 20 has on the proximal side of the proximal end of the electrode arrangement section 40D is a wire made of a metal, and examples of the metal include copper, iron, stainless steel, tungsten, nickel-titanium alloy, carbon steel, etc. Among these, stainless steel is preferable from the viewpoint of strength.

[0046] The wire 35 that the inner tube 30 has in the electrode arrangement section 40D may be a metal wire as described above or a resin wire. Here, the resin wire is a wire made of resin, and examples of the resin include polyamide resin such as nylon, polyimide resin, polyester resin such as PET, and aromatic polyether ketone resin such as PEEK.

[0047] Since the outer tube 20 does not have a metal wire 25 distal to the proximal end of the electrode arrangement section 40D, it becomes easy to form side holes 21 in the outer tube 20 for passing conductors 50 connected to multiple electrodes 40 arranged in the electrode arrangement section 40D on the outer surface of the outer tube 20.

[0048] 3 to 7, the outer tube 20 preferably does not have any wire material, such as a resin wire material, other than the metal wire material 25 from the proximal end of the electrode arrangement section 40D to the distal side. This makes it easier to form the side hole 21 in the outer tube 20 for passing the conductive wire 50 therethrough.

[0049] 3 to 6, the inner tube 30 has a wire 35 in the electrode arrangement section 40D. A side hole 21 is formed in the outer tube 20 from the proximal end to the distal side of the electrode arrangement section 40D, and even if the outer tube 20 does not have a metal wire 25 in this section, the wire 35 of the inner tube 30 can prevent a decrease in strength of the section in which the side hole 21 is formed. This makes it possible to prevent problems such as kinking when the electrode catheter 10 is inserted into a curved body cavity such as the coronary sinus, even if the diameter of the electrode catheter 10 is reduced and the outer tube 20 and inner tube 30 become thinner.

[0050] The inner tube 30 preferably has wire 35 on the side wall of the resin tube in the electrode arrangement section 40D. The wire 35 may be embedded in the side wall of the resin tube constituting the inner tube 30, or may be exposed on the outer or inner surface of the side wall of the resin tube. It is preferable that at least a part of the wire 35 is covered with the resin constituting the inner tube 30. This makes it possible to prevent the wire 35 from falling off the inner tube 30.

[0051] The inner tube 30 has a multi-layer structure composed of a resin tube having an inner layer and an outer layer, and preferably has the wire 35 in the outer layer. This prevents the wire 35 from being exposed in the lumen 30a of the inner tube 30, and the inner wall of the inner tube 30 can be composed of resin, improving the ease of insertion when inserting a treatment tool such as a guidewire or forceps into the lumen 30a of the inner tube 30. Alternatively, the wire 35 may be disposed in the inner layer, or between the inner layer and the outer layer. The inner tube 30 may also have layers other than the inner layer and the outer layer, and the wire 35 may be disposed in or between the other layers.

[0052] 3, the wire 35 of the inner tube 30 is preferably disposed over the entire electrode arrangement section 40D in the longitudinal axis direction x. By disposing the wire 35 over the entire electrode arrangement section 40D in the longitudinal axis direction x, a decrease in strength of the section in which the side hole 21 is formed can be easily prevented.

[0053] Alternatively, as shown in FIG. 4, the wire 35 of the inner tube 30 may be disposed in a part of the electrode arrangement section 40D in the longitudinal axis direction x. Even if the section in which the wire 35 is disposed in the longitudinal axis direction x is a part of the electrode arrangement section 40D, the wire 35 can be disposed to prevent a decrease in strength of the section in which the side hole 21 is formed. The section in which the wire 35 is disposed in the longitudinal axis direction x is preferably 25% or more of the electrode arrangement section 40D, more preferably 30% or more, and even more preferably 50% or more. By setting the lower limit of the section in which the wire 35 is disposed in the longitudinal axis direction x within the above range, the effect of preventing a decrease in strength of the section in which the side hole 21 is formed can be ensured. In addition, the section in which the wire 35 is disposed in the longitudinal axis direction x may be 100% or less of the electrode arrangement section 40D, preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. By setting the upper limit of the section in which the wire 35 is disposed in the longitudinal axis direction x within the above range, the flexibility of the inner tube 30 can be improved. The wires 35 may be arranged continuously or discontinuously in the longitudinal axis direction x. When the wires 35 are arranged discontinuously in the longitudinal axis direction x, it is preferable that the total length of the wires 35 in the longitudinal axis direction x falls within the above range.

[0054] Even when the wire 35 is disposed in a part of the electrode arrangement section 40D in the longitudinal direction x, it is preferable that the section in which the wire 35 is disposed in the longitudinal direction x overlaps with the section in which the side holes 21 and the recesses 22 are formed. This makes it easier to prevent a decrease in strength in the electrode catheter 10 in those parts, since the strength of the inner tube 30 is improved by the wire 35 of the inner tube 30, even in those parts where the strength of the outer tube 20 is likely to be reduced by the side holes 21 and the recesses 22.

[0055] As shown in Figures 5 and 6, in a cross section perpendicular to the longitudinal axis direction x, the wire rods 35 are preferably arranged in a plurality of positions spaced apart in the circumferential direction z. Alternatively, the wire rods 35 may be arranged continuously in the circumferential direction z. With such a configuration, it is possible to more easily prevent a decrease in strength of the section in which the side holes 21 are formed. Specific examples of the configuration of the wire rod 35 include a coil in which a single wire is wound in a spiral shape, and a braid in which multiple wires are woven in a mesh pattern, as will be described later. Figures 5 and 6 show an embodiment in which the wire rod 35 is a braid in which multiple wires are woven in a mesh pattern.

[0056] The positions at which the wires 35 are provided in the circumferential direction z may be the same or different along the longitudinal axis direction x. Moreover, the wires 35 may be disposed at the same position in the radial direction y or at different positions in the radial direction y.

[0057] Since the outer tube 20 has the metal wire 25 proximal to the proximal end of the electrode arrangement section 40D, the electrode catheter 10 can be improved in ability to transmit a force generated by an operation from the proximal side to the distal side of the electrode catheter 10, i.e., in pushability. Even if the diameter of the electrode catheter 10 is reduced and the outer tube 20 and the inner tube 30 are thin, the insertability of the electrode catheter 10 can be improved when the electrode catheter 10 is inserted into a curved body cavity such as the coronary sinus.

[0058] The metal wire 25 of the outer tube 20 may be embedded in the side wall of the resin tube constituting the outer tube 20, or may be exposed on the outer or inner surface of the side wall of the resin tube. It is preferable that at least a part of the metal wire 25 is covered with the resin constituting the outer tube 20. This can prevent the metal wire 25 from falling off the outer tube 20.

[0059] Among them, it is preferable that the outer tube 20 has a multi-layer structure composed of a resin tube having an inner layer and an outer layer, and the metal wire 25 is disposed in the outer layer. This prevents the metal wire 25 from being exposed to the outside of the outer tube 20 or the lumen 20a, and prevents the metal wire 25 from damaging components such as the conductor 50 disposed in the lumen 20a or the wall of a body cavity such as the inner wall of a heart or blood vessel. Alternatively, the metal wire 25 may be disposed in the inner layer, or between the inner layer and the outer layer. The outer tube 20 may have layers other than the inner layer and the outer layer, and the metal wire 25 may be disposed in or between the other layers.

[0060] The metal wire 25 of the outer tube 20 may extend to the proximal end of the outer tube 20. This can further improve the strength of the outer tube 20.

[0061] In the longitudinal axis direction x, the length from the distal end of the metal wire 25 of the outer tube 20 to the proximal end of the most proximal electrode 41 can be 200 mm or less, 190 mm or less, 185 mm or less, 180 mm or less, etc. In this way, the metal wire 25 of the outer tube 20 is provided close to the most proximal electrode 41, thereby improving the strength of the distal part of the electrode catheter 10. In addition, in the longitudinal axis direction x, the length L2 from the distal end of the metal wire 25 of the outer tube 20 to the proximal end of the most proximal electrode 41 can be 80 mm or more, 100 mm or more, 150 mm or more, etc. By providing the metal wire 25 of the outer tube 20 at a certain distance from the most proximal electrode 41, it is possible to prevent the metal wire 25 from affecting the electrode 40 and the conductor 50.

[0062] As shown in Fig. 8, in a cross section perpendicular to the longitudinal axis direction x, the metal wires 25 of the outer tube 20 are preferably arranged in a plurality of positions spaced apart from each other in the circumferential direction z. Alternatively, the metal wires 25 may be arranged continuously in the circumferential direction z. With such a configuration, the rigidity of the outer tube 20 in the circumferential direction z can be made uniform, and pushability can be more easily improved. Specific examples of the configuration of the metal wires 25 include a coil in which a single wire is wound in a spiral shape, a braid in which a plurality of wires are woven in a mesh shape, and the like, as will be described later. Fig. 10 shows an embodiment in which the metal wire 25 is a braid in which a plurality of wires are woven in a mesh shape.

[0063] The positions at which the metal wires 25 are provided in the circumferential direction z may be the same or different along the longitudinal axis direction x. Moreover, the metal wires 25 may be disposed at the same position in the radial direction y or at different positions in the radial direction y.

[0064] 3, the inner tube 30 preferably extends to the distal end of the electrode catheter 10. With this configuration, by forming the inner wall of the inner tube 30 from a fluororesin having high slipperiness, it is possible to further improve the ease of insertion of a treatment tool such as a guidewire or forceps into the lumen 30a of the inner tube 30.

[0065] As shown in Fig. 3, in the longitudinal axis direction x, the distal end of the wire 35 of the inner tube 30 is preferably located proximal to the distal end of the inner tube 30. By having the distal end of the wire 35 located proximal to the distal end of the inner tube 30, the wire 35 is not present at the distal end of the inner tube 30 as shown in Fig. 7, and therefore the flexibility of the distal end of the inner tube 30 can be improved. Although the inner tube 30 preferably extends to the distal end of the electrode catheter 10, this can improve the flexibility of the distal end of the electrode catheter 10 and prevent damage when the electrode catheter 10 abuts against a body cavity wall such as the inner wall of a heart or blood vessel.

[0066] As shown in FIG. 3, the length L1 from the distal end of the wire 35 to the distal end of the inner tube 30 in the longitudinal axis direction x can be 0.5 times or more, 1 time or more, 2 times or more, 3 times or more, 5 times or more, etc., of the length of the most distal electrode 42. In this way, the distal end of the wire 35 is located a predetermined distance or more away from the distal end of the inner tube 30, thereby improving the flexibility of the distal end of the electrode catheter 10. Also, the length L1 from the distal end of the wire 35 to the distal end of the inner tube 30 in the longitudinal axis direction x can be 20 times or less, 15 times or less, 10 times or less, 8 times or less, etc., of the length of the most distal electrode 42. This allows the distal end of the wire 35 to be provided close to the distal end of the inner tube 30, making it easy to provide the electrode arrangement section 40D at the distal end of the electrode catheter 10.

[0067] As shown in Figures 3 and 4, it is preferable that the inner tube 30 does not have a wire 35 proximal to the distal end of the metal wire 25 of the outer tube 20 in the longitudinal axis direction x. In the electrode catheter 10, the outer tube 20 has the metal wire 25 in a section from the distal end of the metal wire 25 of the outer tube 20 to the proximal side. If the inner tube 30 also has the wire 35 in this section, the inner tube 30 may be twisted due to the overlapping of the tubes with high rigidity. However, since the inner tube 30 does not have the wire 35 proximal to the distal end of the metal wire 25 of the outer tube 20 in the longitudinal axis direction x, such twisting can be prevented.

[0068] As shown in Figures 3 and 4, in the longitudinal axis direction x, it is preferable that the proximal end of the wire 35 of the inner tube 30 and the distal end of the metal wire 25 of the outer tube 20 are at the same position, or the proximal end of the wire 35 of the inner tube 30 is located distal to the distal end of the metal wire 25 of the outer tube 20. In particular, it is preferable that there is a portion in the longitudinal axis direction where no wire is disposed between the distal end of the metal wire 25 of the outer tube 20 and the proximal end of the wire 35 of the inner tube 30. As a result, the metal wire 25 of the outer tube 20 and the wire 35 of the inner tube 30 do not overlap in the longitudinal axis direction x, thereby improving flexibility and preventing the above-mentioned twisting.

[0069] In the longitudinal axis direction x, the length L2 of the portion where no wire is arranged from the proximal end of the wire 35 of the inner tube 30 to the distal end of the metal wire 25 of the outer tube 20 is preferably 0 times or more, 0.2 times or more, 0.5 times or more, 1 time or more, 1.5 times or more, 2 times or more, etc., of the length of the most proximal electrode 41. If the lower limit of the length L2 is within the above range, the metal wire 25 of the outer tube 20 and the wire 35 of the inner tube 30 do not overlap, so flexibility can be ensured. In addition, the length L2 is preferably 10 times or less, 8 times or less, 7 times or less, 6 times or less, 5 times or less, etc. If the upper limit of the length L2 is within the above range, the gap between the metal wire 25 of the outer tube 20 and the wire 35 of the inner tube 30, i.e., the length of the section where no wire exists, does not become too long, so that a rigidity step can be prevented and kinking can be prevented in the gap.

[0070] 9 and 10, the proximal end of the wire 35 of the inner tube 30 may be located proximally of the distal end of the metal wire 25 of the outer tube 20 in the longitudinal axis direction x. This allows a portion to be formed in which the outer tube 20 has the metal wire 25 and the inner tube 30 has the wire 35 in a section from the distal end of the metal wire 25 of the outer tube 20 to the proximal side in the longitudinal axis direction x, thereby improving the strength of this portion and preventing defects such as kinking.

[0071] In the longitudinal axis direction x, the length L3 of the portion from the distal end of the metal wire 25 of the outer tube 20 to the proximal side, in which the outer tube 20 has the metal wire 25 and the inner tube 30 has the wire 35, can be 0.2 times or more, 0.5 times or more, 1 time or more, 2 times or more, 5 times or more, etc., of the length of the electrode arrangement section 40D. By setting the lower limit of the length L3 within the above range, the strength of the distal part of the electrode catheter 10 can be ensured. In addition, the upper limit of the length L3 is not particularly limited, and the wire 35 of the inner tube 30 may be arranged up to the proximal end of the inner tube 30 to form a portion in which the outer tube 20 has the metal wire 5 and the inner tube 30 has the wire 35 at the proximal end of the electrode catheter 10, but for example, L3 can be 100 times or less, 50 times or less, 30 times or less, 10 times or less, etc., of the length of the electrode arrangement section 40D.

[0072] The metal wire 25 of the outer tube 20 is preferably at least one of a coil in which a wire is wound in a spiral shape as shown in Fig. 11 and a braid in which a wire is woven in a mesh shape as shown in Fig. 12. The cross-sectional shape of the wire constituting the coil and / or braid of the metal wire 25 of the outer tube 20 is preferably a circle, an ellipse, a rectangle, or the like.

[0073] The diameter of the wire constituting the metal wire 25 of the outer tube 20 when the cross-sectional shape is circular, or the major axis when the wire is elliptical, can be, for example, 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, and 0.12 mm or less, 0.11 mm or less, 0.1 mm or less, etc. When the cross-sectional shape of the wire is rectangular, the length of the short side can be 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, and 0.08 mm or less, 0.07 mm or less, 0.06 mm or less, 0.05 mm or less, etc., and the length of the long side can be 0.05 mm or more, 0.06 mm or more, 0.07 mm or more, and 0.12 mm or less, 0.11 mm or less, 0.1 mm or less, etc.

[0074] The wire 35 of the inner tube 30 is preferably at least one of a coil in which a wire is wound in a spiral shape as shown in Fig. 11 and a braid in which a wire is woven in a mesh shape as shown in Fig. 12. The cross-sectional shape of the wire constituting the coil and / or braid of the wire 35 of the inner tube 30 is preferably a circle, an ellipse, a rectangle, or the like.

[0075] The diameter of the wire constituting the wire 35 of the inner tube 30 when the cross-sectional shape is circular, or the major axis when the wire is elliptical, can be, for example, 0.008 mm or more, 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, and 0.1 mm or less, 0.08 mm or less, 0.07 mm or less, etc. When the cross-sectional shape of the wire is rectangular, the length of the short side can be 0.008 mm or more, 0.01 mm or more, 0.02 mm or more, and 0.08 mm or less, 0.07 mm or less, 0.06 mm or less, 0.05 mm or less, etc., and the length of the long side can be 0.04 mm or more, 0.05 mm or more, 0.06 mm or more, and 0.1 mm or less, 0.08 mm or less, 0.07 mm or less, etc.

[0076] The metal wire 25 of the outer tube 20 and the wire 35 of the inner tube 30 are coils in which a wire is wound in a helical shape, and it is preferable that the coil pitch of the inner tube 30 is smaller than the coil pitch of the outer tube 20. This allows the coil of the wire 35 of the inner tube 30 to be dense, making it easier to prevent a decrease in strength in the section where the side hole 21 is formed in the outer tube 20 by the wire 35 of the inner tube 30. In addition, since the coil of the metal wire 25 of the outer tube 20 can be sparse, the flexibility of the outer tube 20 can be improved.

[0077] Here, the coil is formed by winding a wire in a spiral shape, and the coil pitch is the length P1 in the longitudinal direction from the center of the wire to the center at the same circumferential position when the wire is wound once as shown in Fig. 11. The coil pitch of the outer tube 20 is preferably 0.5 mm or more, more preferably 1.0 mm or more, even more preferably 1.2 mm or more, preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. The coil pitch of the inner tube 30 is preferably 90% or less of the coil pitch of the outer tube 20, more preferably 85% or less, even more preferably 80% or less, preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, and particularly preferably 50% or more.

[0078] The metal wire 25 of the outer tube 20 and the wire 35 of the inner tube 30 are braids in which element wires are woven in a mesh pattern, and it is preferable that the pitch of the braid of the inner tube 30 is smaller than the pitch of the braid of the outer tube 20. This allows the braid of the wire 35 of the inner tube 30 to be dense, making it easier to prevent a decrease in strength in the section where the side holes 21 are formed in the outer tube 20 by the wire 35 of the inner tube 30. In addition, the coils of the metal wire 25 of the outer tube 20 can be sparse, improving the flexibility of the outer tube 20.

[0079] Here, the braid is formed by winding a plurality of wires in a spiral shape and interweaving the wires with each other, and the pitch of the braid is the length P2 in the longitudinal direction from the center of the wire to the center at the same circumferential position when one wire is wound once, as shown in Fig. 12. The pitch of the braid of the outer tube 20 is preferably 1.0 mm or more, more preferably 1.5 mm or more, even more preferably 2.0 mm or more, preferably 6 mm or less, more preferably 5 mm or less, and even more preferably 4 mm or less. The pitch of the braid of the inner tube 30 is preferably 90% or less of the pitch of the braid of the outer tube 20, more preferably 85% or less, even more preferably 80% or less, preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, and particularly preferably 50% or more.

[0080] As shown in Figs. 1 and 2, the electrode catheter 10 may have a tip 70. Examples of the tip 70 include a hollow tube member, a hemispherical member, a lid-shaped member, and the like connected to the distal end of the outer tube 20. The hemispherical member or the lid-shaped member may have a through-hole through which a guide wire can be inserted. By having the tip 70 of the electrode catheter 10, it is possible to prevent unexpected foreign matter such as blood from entering the lumen 20a of the outer tube 20 in which the conductor 50 is arranged during use of the electrode catheter 10. In addition, by forming the tip 70 from a highly flexible material, it is possible to prevent the tip of the electrode catheter 10 from damaging the wall of a body cavity such as the inner wall of the heart or blood vessels, and to improve the insertability of the electrode catheter 10 in a body cavity.

[0081] As the material constituting the distal tip 70, for example, the material constituting the outer tube 20 and the inner tube 30 can be referred to. Alternatively, the distal tip 70 can be made to function as a distal electrode by constituting the distal tip 70 with the material constituting the electrode 40. However, it is preferable that the most distal electrode 42 is an electrode disposed proximal to the proximal end of the distal tip 70, and the distal end of the electrode arrangement section 40D is disposed proximal to the proximal end of the distal tip 70. [Explanation of symbols]

[0082] 10: Electrode catheter 20: Outer tube 20a: Lumen of outer tube 21: Side hole 25: Metal wire 30: Inner tube 30a: Lumen of inner tube 35: Wire rod 40: Electrode 40D: Electrode placement section 41: Most proximal electrode 42: Most distal electrode 50: Conductor 51: Conductive tube 52: Connector 60: Handle 61: Guidewire tube 62: Guidewire port 70: Tip

Claims

1. An electrode catheter having a longitudinal axis and a radial direction perpendicular to the longitudinal axis, the electrode catheter having a distal end and a proximal end along the longitudinal axis, an outer tube having a lumen extending in the longitudinal direction; an inner tube extending into a lumen of the outer tube; a plurality of electrodes spaced apart along the longitudinal axis on an outer surface of the distal portion of the outer tube; a plurality of conductors extending through a lumen of the outer tube and outside the inner tube, the conductors being connected to the plurality of electrodes, respectively; the inner tube has a wire in an electrode arrangement section from a proximal end of a most proximal electrode arranged most proximally among the plurality of electrodes in the longitudinal axis direction to a distal end of a most distal electrode arranged most distally among the plurality of electrodes, An electrode catheter in which the outer tube has a metal wire proximal to the proximal end of the electrode placement section, and does not have the metal wire distal to the proximal end of the electrode placement section.

2. 2. The electrode catheter according to claim 1, wherein the inner tube does not have the metal wire on a proximal side of a distal end of the metal wire of the outer tube in the longitudinal axis direction.

3. 3. An electrode catheter as described in claim 1 or 2, wherein, in the longitudinal axis direction, the proximal end of the wire of the inner tube and the distal end of the metal wire of the outer tube are at the same position, or the proximal end of the wire of the inner tube is located distal to the distal end of the metal wire of the outer tube.

4. 3. The electrode catheter according to claim 1, wherein a distal end of the wire of the inner tube is located proximal to a distal end of the inner tube in the longitudinal axis direction.

5. 3. The electrode catheter according to claim 1, wherein the metal wire of the outer tube is at least one of a helically wound coil and a braid woven in a mesh pattern.

6. 3. The electrode catheter according to claim 1, wherein the wire of the inner tube is at least one of a helically wound coil and a braid woven in a mesh pattern.

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