Catheter and manufacturing method therefor

To provide a catheter having electrodes to be subjected to application of voltages different from each other in polarity. An outer tube member (3) having a lumen (2); a handle provided on a proximal side of the outer tube member (3); a plurality of electrodes (5) provided on the outer tube member (3); conducting wires (6) connected to one or more of the electrodes (5) and disposed in the lumen (2), the conducting wires (6); and an operating wire (7) having a distal end portion fixed to a distal end portion of the outer tube member (3), wherein one of the electrodes (5a) is connected to a conducting wire (6a) at a connection point, which is different from a connecting point, where another electrode (5b) is connected to another conducting wire (6b), in a circumferential direction of the outer tube member (3).

TECHNICAL FIELD

The present invention relates to a catheter of which an outer tube member has electrodes.

BACKGROUND ART

In a checkup or a therapy for arrhythmia such as atrial fibrillation, a catheter having electrodes may be used. At the time of the checkup, the catheter is inserted into a heart chamber, where an intracardiac potential is measured to identify an abnormal site in the heart that is the cause of the arrhythmia. At the time of the therapy, high-frequency current is caused to flow from the electrodes of the catheter to a cardiac muscle that is the cause of the arrhythmia, and the source of the arrhythmia is cauterized, thereby electrically ablating the source from the heart (ablation surgery). Meanwhile, if atrial fibrillation naturally occurs or atrial fibrillation is caused for identifying the abnormal site of the heart during the checkup or the therapy, electrical stimulation is applied to the heart from the electrodes of the catheter, to perform defibrillation.

As such a catheter, a catheter is known which includes: an insulating tube member having a multi-lumen structure; a first electrode group composed of a plurality of ring-shaped electrodes mounted in a distal end region of the tube member; a second electrode group composed of a plurality of ring-shaped electrodes mounted in the distal end region of the tube member so as to be apart from the first electrode group to a proximal end side; a first lead wire group composed of lead wires (conducting wires) connected to the respective electrodes composing the first electrode group; and a second lead wire group composed of lead wires connected to the respective electrodes composing the second electrode group, wherein the first lead wire group and the second lead wire group extend through different lumina in the tube member, and voltages different from each other in polarity are applied between the first electrode group and the second electrode group, to perform defibrillation in a heart chamber (for example, Patent Literatures 1 to 4).

PRIOR ART DOCUMENTS

Patent Documents

SUMMARY OF INVENTION

Problems to be Solved by the Invention

In the catheters disclosed in Patent Literatures 1 to 4, a catheter inner cavity is of a multi-lumen structure, and conducting wires are disposed in different lumina by the polarity of voltage to be applied, whereby insulation property is ensured. However, since the catheters disclosed in Patent Literatures 1 to 4 have a multi-lumen structure, the space through which the conducting wires and the like pass is limited in the inner cavity of the tube member. Therefore, it is difficult to: increase the number of electrodes to be disposed on the catheter in order to enable intracardiac potentials to be measured at more positions with use of the one catheter; and reduce the diameter of the catheter in order to facilitate insertion of the catheter into a target site.

In addition, since the catheters disclosed in Patent Literatures 1 to 4 have a multi-lumen structure, the tube member becomes stiff, whereby problems arise in that: bending of a distal end portion of the catheter is difficult to finely control; and an electrode may be separated from the catheter when the catheter is bent.

These problems can be ameliorated by the following measure. Instead of disposing conducting wires in different lumina by polarity, conducting wires to be subjected to application of voltages different from each other in polarity are disposed in a same lumen, thereby obtaining a catheter having a configuration with a smaller number of lumina. However, by simply disposing the plurality of conducting wires in the same lumen, the insulation property between the conducting wires to be subjected to application of voltages different from each other in polarity may become insufficient.

The present invention has been made in view of the aforementioned circumstances, and an object of the present invention is to provide a catheter which has a plurality of electrodes to be subjected to application of voltages different from each other in polarity, and in which conducting wires connected to the electrodes are disposed in a same lumen but insulation property between the conducting wires is improved.

Solutions to the Problems

A catheter of the present invention that has solved the above problems comprising: an outer tube member having a lumen extending in a longitudinal direction; a handle provided on a proximal side of the outer tube member; a plurality of electrodes provided on the outer tube member; conducting wires connected to one or more of the electrodes and disposed in the lumen, the conducting wires each having a coating; and a wire having a distal end portion fixed to a distal end portion of the outer tube member, wherein a connection point between one of the electrodes and a conducting wire among the conducting wires and a connection point between another one of the electrodes and a conducting wire among the conducting wires are at different locations in a circumferential direction of the outer tube member, and the conducting wire connected to the one of the electrodes and the conducting wire connected to the another one of the electrodes are disposed in the same lumen of the outer tube member.

A method for manufacturing a catheter of the present invention that has solved the above problems comprising: an outer tube member having a lumen extending in a longitudinal direction, a handle provided on a proximal side of the outer tube member, a plurality of electrodes provided on a distal side of the outer tube member, conducting wires connected to one or more of the electrodes and disposed in the lumen and in the handle, the conducting wires each having a coating, an inner tube member disposed in the lumen, and a wire having a proximal end portion disposed in an inner cavity of the handle, and having a distal end portion fixed to a distal end portion of the outer tube member, a connection point between one of the electrodes and a conducting wire among the conducting wires and a connection point between another one of the electrodes and a conducting wire among the conducting wires being at different locations in a circumferential direction of the outer tube member, the conducting wire connected to the one of the electrodes and the conducting wire connected to the another one of the electrodes being disposed in the same lumen of the outer tube member, the manufacturing method comprising: a first step of disposing the conducting wires in the outer tube member; and a second step of disposing at least one of the inner tube member or the wire in the outer tube member, wherein the second step is performed after the first step.

Effects of the Invention

According to the present invention, in the catheter in which the plurality of conducting wires to be subjected to application of voltages different from each other in polarity are disposed in the same lumen, insulation property between the conducting wires can be improved.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be more specifically described based on the following embodiment. However, the present invention is not limited to the following embodiment and, as a matter of course, can also be carried out with appropriate modifications being made within the scope of the gist described above and below, and any of these modifications are included in the technical scope of the present invention. In any of the drawings, hatching, reference characters for members, or the like may be omitted for convenience. In this case, see the description and the other drawings. Since priority is given to facilitating the understanding of the characteristics of the present invention, the dimensions of various members in the drawings may be different from actual dimensions.

FIG.1is a plan view of a catheter according to an embodiment of the present invention.FIG.2is a cross-sectional view of the catheter according to the embodiment of the present invention, along a longitudinal direction. An entire configuration of the catheter according to the embodiment of the present invention will be described with reference toFIG.1andFIG.2. A catheter1includes: an outer tube member3having a lumen2extending in the distal-proximal direction; a handle4provided on a proximal side of the outer tube member3; a plurality of electrodes5provided on the outer tube member3; conducting wires6connected to one or more of the electrodes5and disposed in the lumen2, the conducting wires6each having a coating; and a wire7having a distal end portion fixed to a distal end portion of the outer tube member3. A proximal end portion of the wire7is joined to the handle4. The catheter1is caused to, for example, pass from a distal side thereof through the inside of a blood vessel of a patient to reach the heart so that the catheter1is used for a checkup or a therapy for arrhythmia, or defibrillation in the heart.

In the present invention, the proximal side refers to the hand side of a user in the extending direction of the outer tube member3, and the distal side refers to the side opposite to the proximal side, that is, the treatment target side. The extending direction of the outer tube member3is referred to as an axial direction. A radial direction refers to the radial direction of the outer tube member3, a radially inward direction refers to a direction toward the axial center side of the outer tube member3, and a radially outward direction refers to a direction toward the side opposite to the radially inner side.

Regarding the catheter1, the distal end of the catheter1can be bent or linearly extended by manipulating the handle4. The distal end portion of the wire7is fixed to the distal end portion of the outer tube member3, and thus, when the wire7is moved in the axial direction, the distal end portion of the outer tube member3fixed to the wire7moves in association with the movement of the wire7so that the distal side of the outer tube member3is bent to one side3a.

FIG.3is a III-III cross-sectional view of the catheter shown inFIG.2.FIG.4is a IV-IV cross-sectional view of the catheter shown inFIG.2. As shown inFIG.3andFIG.4, the electrodes5include at least a one-side electrode5aand an other-side electrode5b. In the catheter1, a connection point8abetween the one-side electrode5aand a conducting wire6aand a connection point8bbetween the other-side electrode5band a conducting wire6bare at different locations in a circumferential direction of the outer tube member3. Since the connection point8abetween the one-side electrode5aand the conducting wire6aand the connection point8bbetween the other-side electrode5band the conducting wire6bare thus located, a sufficient distance can be maintained between the conducting wire6aand the conducting wire6bso that a sufficient insulation property therebetween can be obtained, even though the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bto be subjected to application of a voltage different in polarity from a voltage for the one-side electrode5aare disposed in the same lumen2. Therefore, it becomes unnecessary to dispose the conducting wires in different lumina by polarity. Defibrillation can be performed by applying voltages different from each other in polarity to the one-side electrode5aand the other-side electrode5b.

FIG.5is a V-V cross-sectional view of the catheter shown inFIG.2. As in the catheter shown inFIG.3andFIG.4, the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bare disposed in the same lumen2of the outer tube member3. Since the conducting wires6aand6bare disposed in the same lumen2of the outer tube member3, a plurality of lumina2for disposing therein the conducting wires separately by polarity do not have to be provided, whereby an inner cavity of the outer tube member3can be widened. Accordingly, the number of conducting wires6that can be disposed in the catheter1can be increased, and thus the number of electrodes5of the catheter1can be increased more. In addition, since the number of lumina2in the catheter1can be reduced, the diameter of the catheter1can be further reduced, and the flexibility of the outer tube member3can be improved. If the number of lumina2is small, it becomes unnecessary to form partition walls for forming the lumina2, and thus the flexibility of the outer tube member3can be improved. If the number of electrodes5of the catheter1is increased, the accuracies of a checkup and a therapy can be improved. In addition, if the diameter of the catheter1is reduced or the flexibility is improved, the movement of the distal end of the catheter1can be accurately controlled. In addition, if the outer tube member3becomes flexible, the electrodes5sink into the outer tube member3, to become less likely to be separated therefrom. Accordingly, the electrodes5can be prevented from being separated at the time of bending.

The outer tube member3has a flexible tubular structure, and can be formed from, for example: a synthetic resin such as a polyolefin-based resin such as polyethylene or polypropylene, a polyamide-based resin such as nylon, a polyester-based resin such as PET, an aromatic polyether ketone-based resin such as PEEK, a polyether polyamide-based resin, a polyurethane-based resin, a polyimide-based resin, a fluorine-based resin such as PTFE, PFA, or ETFE, or a polyvinyl chloride-based resin; a metal such as stainless steel, carbon steel, or a nickel-titanium alloy; or the like. The outer tube member3may have a single-layer structure or a multi-layer structure. In a case where the outer tube member3has a multi-layer structure, the layers may be formed from the same material or different materials. For example, a structure in which a metal braid is used as an intermediate layer in a resin tube can be employed. The material of the outer tube member3is preferably a fluorine-based resin and more preferably PTFE. If the outer tube member3is thus formed, it is possible to obtain a catheter1of which insertion into a blood vessel is facilitated.

As the length in the axial direction of the outer tube member3, a length that is appropriate for a therapy can be selected. For example, the length in the axial direction of the outer tube member3can be set to be not smaller than 500 mm and not larger than 1200 mm. The catheter1of the present invention allows the state of insulation between the conducting wires6to be maintained even if the length of the catheter1is increased.

The outer diameter of the outer tube member3is, for example, preferably not smaller than 0.6 mm, more preferably not smaller than 0.8 mm, and further preferably not smaller than 1.0 mm. If the lower limit value for the outer diameter of the outer tube member3is thus set, the outer tube member3comes to have an appropriate rigidity, and insertion of the catheter1into a blood vessel can be facilitated. In the case of a multi-lumen catheter, the outer diameter of the catheter is set to be about 2.0 mm in order to provide a plurality of lumina, whereby it is difficult reduce the outer diameter of the catheter. In contrast, the structure of the present invention makes it possible to provide a catheter having a smaller outer diameter. Meanwhile, the outer diameter of the outer tube member3is preferably not larger than 3.0 mm, more preferably not larger than 2.8 mm, and further preferably not larger than 2.5 mm. If the upper limit value for the outer diameter of the outer tube member3is thus set, the outer tube member3becomes less likely to come into contact with the inner wall of a blood vessel at the time of insertion of the catheter1, whereby burden on the patient can be reduced.

In a case where the outer tube member3has a single lumen, the thickness of the outer tube member3is preferably not smaller than 50 μm, more preferably not smaller than 100 μm, and further preferably not smaller than 150 μm. If the lower limit value for the thickness of the outer tube member3is thus set, an appropriate rigidity is imparted to the outer tube member3, and it is possible to obtain a catheter1of which insertion into a blood vessel is facilitated. Meanwhile, the thickness of the outer tube member3is preferably not larger than 350 μm, more preferably not larger than 250 μm, and further preferably not larger than 150 μm. If the upper limit value for the thickness of the outer tube member3is thus set, the lumen2of the outer tube member3can be widened.

The outer tube member3may employ a single-lumen structure having one lumen2therein or a multi-lumen structure having a plurality of lumina2. Among the structures, the structure in which the number of lumina2of the outer tube member3is one is preferable. If the number of lumina2is one, no partition wall or the like is provided in the inner cavity of the outer tube member3. Thus, the flexibility of the outer tube member3can be improved, whereby the bendability of the distal end portion of the catheter1becomes easy to control, and the electrodes5become less likely to be separated at the time of bending. In addition, the inner cavity of the outer tube member3can be widened, and thus it is possible to obtain a catheter having a plurality of electrodes and/or a catheter having a reduced diameter. In the lumen2, for example, the conducting wires6connected to the electrodes5, the wire7, and the like are disposed.

The outer tube member3may have a distal tip9at the distal end thereof. The distal tip9is a lid-like member for closing an opening at the distal end of the outer tube member3. If the outer tube member3has the distal tip9, water in blood or the like is prevented, during use of the catheter1, from entering the lumen2of the outer tube member3and coming into contact with the connection portions between the electrodes5and the conducting wires6. Accordingly, it is possible to prevent: deterioration of insulation property between the plurality of conducting wires6; and occurrence of a drift phenomenon in which the baseline potential in an electrocardiogram becomes unstable when an intracardiac potential is measured. In addition, the distal tip9serves as a guide for the distal end of the catheter1, whereby insertion of the catheter1can be facilitated. Furthermore, the distal tip9can be used as a fixing portion for the wire7. If a fixed end of the wire7is located at the distal tip9portion, the catheter1can be effectively bent by wire manipulation.

A material of the distal tip9is not particularly limited. For example, the aforementioned material of the outer tube member3, a material of each electrode5described later, or the like can be used. If the distal tip9is formed from an electrically conductive material such as the material of the electrode5described later and the distal tip9is connected to any of the conducting wires6, the distal tip9can serve also as an electrode5.

The opening at the distal end of the outer tube member3may be closed by thermal fusion of the distal end portion of the outer tube member3, or the like, without providing any distal tip9at the distal end of the outer tube member3.

The handle4is provided on the proximal side of the outer tube member3. In the handle4, the wire7having the distal end portion fixed to the distal end portion of the outer tube member3and disposed in the inner cavity of the outer tube member3is fixed to the inner wall of the handle4. Therefore, by manipulating the handle4, the wire7is moved in the axial direction so that the outer tube member3can be bent, for example.

The electrodes5include at least the one-side electrode5aand the other-side electrode5b, and the one-side electrode5aand the other-side electrode5bare provided on the outer tube member3so as to be apart from each other on the distal side of the outer tube member3. The catheter1has the plurality of electrodes apart from each other, i.e., the electrodes5aand5b, and thus, with the electrodes5aand5bbeing brought into contact with the inner wall of the heart of a patient, an intracardiac potential can be measured to identify an abnormal site of the heart that is the cause of arrhythmia, and defibrillation can be performed in a heart chamber. When defibrillation is performed, voltages different from each other in polarity may be applied to the electrodes5aand5b. For example, negative voltage may be applied to the one-side electrode5a, and positive voltage may be applied to the other-side electrode5b. The voltages to be applied to the one-side electrode5aand the other-side electrode5bcan be switched in polarity. Specifically, after negative voltage is applied to the one-side electrode5a, positive voltage may be applied thereto.

Although the type of each of the plurality of electrodes5including the one-side electrode5aand the other-side electrode5bis not particularly limited, both an electrode for performing defibrillation and an electrode for measuring an intracardiac potential are preferably provided. For example, the one-side electrode5aand the other-side electrode5bmay be used as electrodes for performing defibrillation by being respectively subjected to application of voltages different from each other in polarity, and a separate electrode different from the one-side electrode5aand the other-side electrode5bmay be used as an electrode for measuring an intracardiac potential. In addition, the electrodes for performing defibrillation can serve also as electrodes for measuring a potential. If the plurality of electrodes5are thus configured, it is possible to, with the one catheter, perform: defibrillation when arrhythmia such as atrial fibrillation occurs; and measurement of an intracardiac potential to identify an abnormal site that is the cause of arrhythmia. The number of one-side electrodes5a, the number of other-side electrodes5b, and the number of separate electrodes may be one or more. The number of one-side electrodes5a, the number of other-side electrodes5b, and the number of separate electrodes may be the same as or different from one another.

The arrangement of the plurality of electrodes5including the one-side electrode5aand the other-side electrode5bis not particularly limited, and, for example, electrodes for performing defibrillation and electrodes for measuring an intracardiac potential are preferably arranged alternately. A specific example of the arrangement is as follows. With the one-side electrode5abeing a negative electrode for performing defibrillation, the other-side electrode5bbeing a positive electrode for performing defibrillation, and the separate electrode different from the one-side electrode5aand the other-side electrode5bbeing an electrode for measuring an intracardiac potential, the electrode for measuring an intracardiac potential is preferably disposed between the negative electrode and the positive electrode for performing defibrillation such that the one-side electrode5awhich is the negative electrode for performing defibrillation, the separate electrode which is different from the one-side electrode5aand the other-side electrode5band which is the electrode for measuring an intracardiac potential, and the other-side electrode5bwhich is the positive electrode for performing defibrillation, are arranged in this order from the distal side to the proximal side of the outer tube member3. If the plurality of electrodes5are thus arranged, the electrode for measuring an intracardiac potential is located at the inner wall of the heart when the electrodes for performing defibrillation are disposed so as to hold the heart therebetween, with the negative electrode for performing defibrillation being disposed at the coronary sinus and the positive electrode for performing defibrillation being disposed at the right atrium. Therefore, when electrical stimulation is applied between the positive electrode and the negative electrode for performing defibrillation, it is possible to quickly check whether or not defibrillation has been successfully performed.

The electrodes5may be ring-shaped electrodes or may be plate electrodes that each have a rectangular shape, a square shape, or the like and that are independently formed into the shapes of islands on the outer tube member3. At least one of the back surface (inner surface) or the front surface (outer surface) of each plate electrode may be a curved surface so as to be easily fitted along the curve of the surface of the outer tube member3. In particular, the electrodes5are preferably ring-shaped. If the electrodes5are ring-shaped, the area of the electrodes5on the circumference of the outer tube member3can be made large, whereby it becomes easy to bring the electrodes5into contact with the inner wall of the heart, and the like.

Examples of a material of each electrode5include metal materials such as copper, gold, platinum, aluminum, iron, and an alloy thereof. In order to obtain a favorable contrasting property with respect to X-rays during use of the catheter1, the electrode5is preferably formed from platinum or an alloy thereof.

The conducting wires6electrically connect the electrodes5and an external device (not shown) for the catheter1to each other, and are disposed in the lumen2of the outer tube member3. As shown inFIG.2toFIG.5, the conducting wires6are connected to the electrodes5and pass in the lumen2of the outer tube member3.

A material for a core of each conducting wire6is not particularly limited as long as the material is an electrically conductive material. For example, an iron wire, a copper wire, a silver wire, a stainless steel wire, a tungsten wire, a nickel-titanium wire, or the like can be used. Among the wires, a stainless steel wire is particularly preferable in that the stainless steel wire has straightness and rigidity, and thus the stainless steel wire allows the conducting wire6to easily pass in the outer tube member3and is less likely to be broken at the connection portion between the conducting wire6and the corresponding electrode5.

The conducting wire6has a coating at a portion thereof other than both end portions connected to other objects such as the electrode5. Specifically, for example, it is preferable that: the coating at one end of the conducting wire6is partially removed; and the portion is connected to the electrode5by welding or the like.

The coating of the conducting wire6only has to be formed from an insulating material, and examples of the insulating material include synthetic resins such as polyolefin-based resins such as polyethylene and polypropylene, polyamide-based resins such as nylon, polyester-based resins such as PET, aromatic polyether ketone-based resins such as PEEK, polyether polyamide-based resins, polyurethane-based resins, polyimide-based resins, fluorine-based resins such as PTFE, PFA, and ETFE, and polyvinyl chloride-based resins. Among the insulating materials, the coating of the conducting wire6is preferably formed from a fluorine-based resin and more preferably formed from PFA. If the coating of the conducting wire6is thus formed, the insulation property of the conducting wire6can be ensured. Furthermore, in the lumen2of the outer tube member3, the slidability of the conducting wire6relative to other objects such as another conducting wire6and the wire7is improved, whereby the coating of the conducting wire6can be prevented from being damaged.

The thickness of the coating of the conducting wire6is preferably not smaller than 20 μm, more preferably not smaller than 25 μm, and further preferably not smaller than 30 μm. If the lower limit value for the thickness of the coating of the conducting wire6is thus set, a sufficient insulation property can be imparted to the conducting wire6. Meanwhile, the thickness of the coating of the conducting wire6is preferably not larger than 50 μm, more preferably not larger than 40 μm, and further preferably not larger than 35 μm. If the upper limit value for the thickness of the coating of the conducting wire6is thus set, it is possible to make the diameter of the conducting wire6small while ensuring a sufficient insulation property of the conducting wire6. Therefore, the conducting wire6can be caused to easily pass in the lumen2of the outer tube member3during manufacturing of the catheter1.

As a method for connecting the conducting wire6to the electrode5, for example, welding, brazing such as soldering, connection by crimping or the like, or the like can be performed. Among the methods, welding is preferable. If the conducting wire6is connected to the electrode5by welding, the connection between the conducting wire6and the electrode5can be easily made firm. In addition, the space on the inner side of the electrode5can be ensured to be widest, and the electrode5is easily attached to the outer tube member3. As a result, workability for manufacturing can be improved. The conducting wire6and the electrode5may be connected to each other with an electrically conductive member interposed therebetween.

The connection portion between the conducting wire6and the electrode5is preferably coated with a resin or the like such that oxidation degradation does not occur owing to water or the like contained in the atmosphere or the like. Examples of the resin to be used for coating of the connection portion between the conducting wire6and the electrode5include polyurethane resins, epoxy resins, and the like.

The conducting wires6include at least the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5b, and the connection point8abetween the one-side electrode5aand the conducting wire6aand the connection point8bbetween the other-side electrode5band the conducting wire6bmay be at different locations in the circumferential direction of the outer tube member3. Specifically, in a cross section perpendicular to the axial direction of the outer tube member3, the distance between the connection point8abetween the one-side electrode5aand the conducting wire6aand the connection point8bbetween the conducting wire6band the other-side electrode5badjacent to the one-side electrode5ais preferably not shorter than L/15, more preferably not shorter than L/10, and further preferably not shorter than L/8, where L represents the length of the outer circumference of the outer tube member3. If the lower limit value for the distance between the connection point8abetween the one-side electrode5aand the conducting wire6aand the connection point8bbetween the other-side electrode5band the conducting wire6bis thus set, the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bbecome less likely to come into contact with each other, whereby insulation property therebetween can be more improved. Although the upper limit value for the distance between the connection point8abetween the one-side electrode5aand the conducting wire6aand the connection point8bbetween the conducting wire6band the other-side electrode5badjacent to the one-side electrode5ais not particularly limited, the distance can be set to be, for example, not longer than L/2. In a case where the number of one-side electrodes5ais two or more and the number of other-side electrode5bis also two or more, all connection points may be at different locations in the circumferential direction, or connection points for electrodes to be subjected to application of voltage of the same polarity may be at the same location in the circumferential direction. The electrodes to be subjected to application of voltage of the same polarity refer to all of the one-side electrodes5aor all of the other-side electrodes5b.

In the cross section perpendicular to the axial direction of the outer tube member3, the angle θ1between a straight line S1passing, as shown inFIG.3, the center point of the smallest circle circumscribing the outer tube member3and the connection point8abetween the one-side electrode5aand the conducting wire6a, and a straight line S2passing, as shown inFIG.4, the center point of the smallest circle circumscribing the outer tube member3and the connection point8bbetween the other-side electrode5band the conducting wire6b, is preferably not smaller than 30 degrees, more preferably not smaller than 45 degrees, and further preferably not smaller than 60 degrees. If the lower limit value for the angle θ1is thus set, the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bbecome less likely to come into contact with each other, whereby insulation property between the conducting wire6aand the conducting wire6bcan be maintained. Although the upper limit value for the angle θ1between the straight line S1and the straight line S2is not particularly limited, the angle θ1can be set to be, for example, not larger than 180 degrees.

It is preferable that, as shown inFIG.3andFIG.4: the outer tube member3has holes10penetrating therethrough in the radial direction; and each conducting wire6connected to the corresponding electrode5is inserted in the corresponding hole10and located in the lumen2of the outer tube member3. If the catheter1is thus configured, a step of disposing the conducting wire6connected to the electrode5in the lumen2of the outer tube member3can be easily performed during manufacturing of the catheter1.

The conducting wires6are connected to the one or more of the electrodes5and disposed in the lumen2. Each one of the conducting wires6is preferably connected to the corresponding electrode5. Accordingly, the electrodes5can be individually controlled. For example, the one-side electrode5acan be used for measuring an intracardiac potential or used for performing defibrillation by being subjected to application of voltage. Alternatively, the conducting wires6may be connected to a plurality of the electrodes5, and, for example, the electrodes5can be connected in series. The electrodes5connected in series can be suitably used for defibrillation. In this case, some of the plurality of the electrodes5may be connected in series to one of the conducting wires6, other electrodes among the plurality of the electrodes5may be connected in series to another conducting wire6, and each one of conducting wires6may be connected to the corresponding electrode5among the remaining ones of the plurality of the electrodes5. Accordingly, electrodes5for use in measurement of a heart potential and electrodes5for use in defibrillation can be used as dedicated electrodes. Also in a case where each one of the conducting wires6is connected to all the electrodes5, each electrode5may be used as a dedicated electrode for measuring an intracardiac potential or for defibrillation.

As shown inFIG.2, the wire7has the distal end portion fixed to the distal end portion of the outer tube member3. Although the wire7only has to be such that the distal end portion of the wire7is fixed to the distal end portion of the outer tube member3, the distal end of the wire7is preferably fixed to the distal end of the inner cavity of the outer tube member3. If the wire7is thus fixed to the outer tube member3, the distal side of the outer tube member3can be greatly bent. In the present description, the phrase “the distal end portion of the wire7is fixed to the distal end portion of the outer tube member3” encompasses: a state where the distal end portion of the wire7is directly fixed to the distal end portion of the outer tube member3; and an indirectly fixed state such as a state where the distal end portion of the wire7is fixed to the distal end portion of the outer tube member3with another object such as the distal tip9therebetween.

Examples of a usable material of the wire7include: metal wire materials formed from stainless steel, carbon steel, a nickel-titanium alloy, or the like; and yarns formed from synthetic resins such as a polyolefin-based resin such as polyethylene or polypropylene, a polyamide-based resin such as nylon, a polyester-based resin such as PET, an aromatic polyether ketone-based resin such as PEEK, a polyether polyamide-based resin, a polyurethane-based resin, a polyimide-based resin, a fluorine-based resin such as PTFE, PFA, or ETFE, or a polyvinyl chloride-based resin. The wire7may have a structure in which a metal material and a synthetic resin material are combined with each other. For example, a wire7obtained by knitting a wire material formed from a metal and a wire material formed from a synthetic resin, or a wire7obtained by coating a metal wire material with a resin, can be used. Among the materials of the wire7, metal wire materials are preferable, and stainless steel is further preferable. If the wire7is thus formed, the wire7can be made less likely to be damaged or deformed even if the wire7is repetitively bent for bending the outer tube member3.

The method for fixing the distal end portion of the wire7and the distal end portion of the outer tube member3to each other is not particularly limited, and examples of the method include brazing such as soldering, welding, adhesion using an adhesive, connection by crimping or the like, and the like. The fixation between the distal end portion of the wire7and the distal end portion of the outer tube member3is preferably as follows. With the outer tube member3having the distal tip9formed from metal at the distal end thereof and the wire7being formed from a metal wire material, the wire7and the distal tip9are fixed to each other by soldering. If the distal end portion of the wire7and the distal end portion of the outer tube member3are thus fixed to each other, the fixation between the wire7and the outer tube member3becomes firm. Accordingly, the wire7becomes less likely to be detached from the outer tube member3even when the wire7is moved in the axial direction in order to bend the distal side of the outer tube member3.

Although the diameter of the wire7is not particularly limited, the diameter is preferably not smaller than 100 μm, more preferably not smaller than 150 μm, and further preferably not smaller than 200 μm. If the lower limit value for the diameter of the wire7is thus set, the strength of the wire7can be made sufficient. Meanwhile, the diameter of the wire7is preferably not larger than 500 μm, more preferably not larger than 450 μm, and further preferably not larger than 400 μm. If the upper limit value for the diameter of the wire7is thus set, the lumen2of the outer tube member3can be ensured to be sufficiently wide.

As shown inFIG.2, when the wire7is moved in the axial direction, the distal side of the outer tube member3is bent to the one side3a. For moving the wire7in the axial direction, a manipulation such as pulling of the wire7to the proximal side may be performed by, for example, winding back the wire7through manipulation of the handle4. Alternatively, the distal side of the outer tube member3can be bent also by pushing the wire7to the distal side. By bending the distal side of the outer tube member3to the one side3a, in the heart, the electrode5that is disposed on the distal side of the outer tube member3can be caused to approach the inner wall of the heart, whereby it becomes easy to bring the electrode5into contact with a target site in the heart.

The number of wires7may be one or more. In a case where the number of wires7is one, the volume of the wire7in the inner cavity of the outer tube member3can be made small, whereby the lumen2of the outer tube member3can be widened. In a case where the number of wires7is two or more, if, for example, a distal end portion of one of the wires is fixed to one side of the distal end portion of the outer tube member3in a cross section perpendicular to the axial direction of the outer tube member3and a distal end portion of another wire is fixed to another side of the distal end portion of the outer tube member3in the cross section perpendicular to the axial direction of the outer tube member3, the distal side of the outer tube member3can be bent in a plurality of directions toward the one side and the other side, whereby it becomes easy to bring the electrode5into contact with various sites in the heart.

It is preferable that, as shown inFIG.2toFIG.4, at least one of the conducting wires6is, in a cross section perpendicular to the axial direction of the outer tube member3at a bending portion11of the outer tube member3, present on at least one position on the one side3aamong the one side3aof the outer tube member3and another side3bopposite to the one side3a. The bending portion11refers to a portion that extends to the distal end of the outer tube member3from a portion that serves as an origin of bending when the outer tube member3is bent by moving the wire7in the axial direction. In the example shown inFIG.3, the conducting wire6aconnected to the one-side electrode5ais present on the one side3aof the outer tube member3. If the conducting wires6are thus disposed, a load is less likely to be applied to each conducting wire6when the outer tube member3is bent, whereby damage to the coating of the conducting wire6and wire breakage can be prevented. Therefore, the insulation property of the conducting wire6can be maintained.

It is preferable that, as shown inFIG.5, the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bare at different locations in the circumferential direction of the outer tube member3. Specifically, the connection point8abetween the one-side electrode5aand the conducting wire6aand the connection point8bbetween the other-side electrode5band the conducting wire6bare at different locations in the circumferential direction of the outer tube member3, and the conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bare at different locations in the circumferential direction of the outer tube member3. Accordingly, the conducting wire6aand the conducting wire6bbecome further less likely to come into contact with each other in the lumen2. Therefore, insulation property therebetween can be further improved.

The catheter1preferably includes an inner tube member12disposed in the lumen2. If the inner tube member12is disposed in the lumen2, the rigidity of the outer tube member3can be improved, and insertion of the catheter1into a blood vessel can be facilitated.

The type of the inner tube member12is not particularly limited, and examples thereof include: cylindrical tubes and pipes; coils obtained by spirally winding a wire material; and the like. Among the types, the inner tube member12is preferably a coil or a pipe, and is more preferably formed by combination thereof. If the inner tube member12is thus formed, it is possible to impart an appropriate flexibility while improving the rigidity of the outer tube member3. Therefore, it is possible to obtain a catheter1of which insertion into a blood vessel is facilitated and which is easily inserted even into a curvy blood vessel.

As a material of the inner tube member12, the same synthetic resin or metal as that for the outer tube member3, or the like can be used. The inner tube member12may have a layered structure. The material of the inner tube member12and the material of the outer tube member3may be the same as or different from each other. The inner tube member12is preferably formed from a metal. Specifically, the inner tube member12is more preferably a coil that is obtained by spirally winding a wire material formed from stainless steel. If the inner tube member12is thus formed, a catheter1is obtained in which bending of the outer tube member3is easily adjusted while a sufficient rigidity is imparted to the outer tube member3.

In a case where the inner tube member12is a pipe, the outer diameter of the distal end of the inner tube member12is preferably smaller than the outer diameter of the proximal end thereof. If the inner tube member12is thus formed, the pushability of the catheter1can be improved. Examples of a method for forming the inner tube member12having a smaller outer diameter at the distal end than at the proximal end thereof include methods that involve: joining of a tube having a larger outer diameter and a tube having a smaller outer diameter; swaging of a metal tube; heating of a part of a tube formed from a heat-shrinkable resin, to reduce the diameter of the part; or the like.

The inner tube member12is preferably provided with: a metal tube having a smaller outer diameter at the distal end than at the proximal end thereof, and a metal coil disposed at the distal side of the metal tube. If the inner tube member12is thus formed, the inner tube member has a higher stiffness at the proximal side thereof and has a lower stiffness at the distal side thereof, whereby force exerted from the hand side of the catheter1can be efficiently transmitted to the distal side. As a result, loss in torque transmission can be reduced.

The wire7is preferably disposed inside the inner tube member12. If the wire7is thus disposed, the wire7becomes less likely to come into contact with the conducting wire6, whereby the coating of the conducting wire6can be prevented from being damaged.

The inner tube member12and the wire7are preferably disposed in the lumen2in which the conducting wires6are disposed. That is, the conducting wires6, the wire7, and the inner tube member12are preferably disposed in the same lumen2of the outer tube member3. Further, the wire7is preferably disposed in the inner cavity of the inner tube member12. If the catheter1is thus configured, it is possible to: reduce the number of lumina2of the outer tube member3, thereby reducing the diameter of the catheter1; and widen the inner cavity of the outer tube member3and increase the number of electrodes5, thereby multi-polarizing the catheter1. In addition, the flexibility of the outer tube member3can be improved.

It is preferable that, as shown inFIG.2andFIG.5, the inner tube member12has a protective member13disposed radially outward of the inner tube member12. If the inner tube member12has the protective member13, the coatings of the conducting wires6can be prevented from being damaged by the inner tube member12coming into contact with the conducting wires6.

A material of the protective member13of the inner tube member12is preferably an insulating material. Regarding specific examples of the material of the protective member13of the inner tube member12, the materials included in the examples of the material of the coating of each of the conducting wire6can be used. Among the materials, the protective member13is preferably formed from a polyolefin-based resin such as polyethylene. If the protective member13is formed from the material, insulation property between the conducting wire6and the inner tube member12can be maintained and safety can be improved, even if the coating of the conducting wire6is damaged in a case where the inner tube member12is formed from a metal.

In addition, the protective member13of the inner tube member12is preferably formed from an insulating material that is different from the material of the coating of the conducting wire6. Specifically, it is more preferable that: the protective member13of the inner tube member12is formed from a polyolefin-based resin; and the coating of the conducting wire6is formed from a fluorine-based resin. If the protective member13is thus formed, the slidability between the protective member13and the conducting wire6is improved. Accordingly, the coating of the conducting wire6can be prevented from being damaged owing to contact between the conducting wire6and the protective member13during manufacturing or usage of the catheter1.

The thickness of the protective member13of the inner tube member12is preferably smaller than the thickness of the outer tube member3and larger than the thickness of the coating of the conducting wire6. If the protective member13is thus formed, the coating of the conducting wire6becomes less likely to be damaged when the protective member13and the conducting wire6come into contact with each other. In addition, the distance between the protective member13and the inner surface of the outer tube member3can be elongated, whereby the conducting wire6and the protective member13become less likely to come into contact with each other.

It is preferable that, as shown inFIG.2, the catheter1includes an elastic member14having a distal end portion fixed to the distal end portion of the outer tube member3and having a proximal end portion fixed to the inner tube member12. The elastic member14extends along the distal-proximal direction. If the catheter1includes the elastic member14, it is possible to finely adjust the extent to which the distal side of the outer tube member3is to be bent by moving the wire7in the axial direction.

The type of the elastic member14is not particularly limited, and examples thereof include flat springs, coil springs, and the like. Among the types, the elastic member14is preferably a flat spring. The flat spring is a spring made using a sheet material, and a cross-sectional shape, of the flat spring, that is taken in the axial direction is rectangular. The flat spring is bent at a long-side portion thereof in the cross-sectional shape. Thus, when the wire7is moved in the axial direction, the long-side portion of the flat spring is bent to the wire7side. Therefore, if the elastic member14is the flat spring, the bending direction of the distal side of the outer tube member3can be fixed.

Examples of a material of the elastic member14include stainless steel, carbon steel, copper alloys, titanium alloys, and the like. Among the materials, the material of the elastic member14is preferably stainless steel. If the elastic member14is thus formed, the extent of the bending of the distal side of the outer tube member3becomes easier to adjust.

Although the distal end portion of the elastic member14only has to be fixed to the distal end portion of the outer tube member3, it is preferable that the distal end of the elastic member14is fixed to the distal end of the inner wall of the outer tube member3. If the distal end of the elastic member14is thus fixed to the outer tube member3, bending of the distal side of the outer tube member3becomes easy to control.

A method for fixing the distal end portion of the elastic member14and the distal end portion of the outer tube member3to each other is not particularly limited, and examples of the method include brazing such as soldering, welding, adhesion using an adhesive, connection by crimping or the like, and the like. The fixation between the distal end portion of the elastic member14and the distal end portion of the outer tube member3is preferably as follows. With the outer tube member3having the distal tip9formed from metal at the distal end thereof and the elastic member14being formed from metal, the elastic member14and the distal tip9are fixed to each other by soldering. If the distal end portion of the elastic member14and the distal end portion of the outer tube member3are thus fixed to each other, the elastic member14can be firmly fixed to the outer tube member3. Accordingly, the elastic member14can be made less likely to be detached from the outer tube member3even when the distal side of the outer tube member3is bent. A step of fixing the elastic member14and the outer tube member3to each other may be performed simultaneously with a step of fixing the wire7and the outer tube member3to each other.

It is preferable that, as shown inFIG.2, the catheter1includes a tubular member15disposed on the proximal side relative to the distal end portion of the wire7. The tubular member15is preferably disposed in the lumen2of the outer tube member3. If the catheter1includes the tubular member15, the coating of the conducting wire6can be prevented from being damaged by the conducting wire6coming into contact with another object such as the wire7disposed in the lumen2of the outer tube member3.

At least one of the wire7or the elastic member14is preferably disposed in an inner cavity of the tubular member15. If the wire7is disposed in the inner cavity of the tubular member15, the coating of the conducting wire6can be prevented from being damaged owing to contact between the wire7and the conducting wire6. In addition, the location of the wire7in the lumen2of the outer tube member3is fixed, whereby it is possible to reduce the distance for the wire7to be moved in the axial direction in order to bend the distal side of the outer tube member3. As a result, the outer tube member3can be finely adjusted in terms of the manner of the bending thereof and can be promptly bent. If the elastic member14is disposed in the inner cavity of the tubular member15, the elastic member14and the conducting wire6are prevented from coming into contact with each other, whereby the coating of the conducting wire6becomes less likely to be damaged. In particular, it is more preferable that the wire7and the elastic member14are disposed in the inner cavity of the tubular member15.

Although a material of the tubular member15is not particularly limited, the material is preferably an insulating material. For example, the insulating materials included in the examples of the material of the coating of the conducting wire6can be used. Among the materials, the material of the tubular member15is preferably a different type of material from the material of the coating of the conducting wire6. For example, in a case where the material of the coating of the conducting wire6is PTFE, the material of the tubular member15is preferably different from PTFE. If the tubular member15is thus formed, the slipperiness between the conducting wire6and the tubular member15can be improved. Accordingly, the coating of the conducting wire6can be prevented from being damaged owing to contact between the conducting wire6and the tubular member15during manufacturing or usage of the catheter1.

The thickness of the tubular member15is preferably smaller than the thickness of the outer tube member3and larger than the thickness of the coating of the conducting wire6. If the tubular member15is thus formed, the distance between the tubular member15and the inner surface of the outer tube member3can be elongated, whereby the conducting wire6and the tubular member15become less likely to come into contact with each other. In addition, the coating of the conducting wire6can be made less likely to be damaged even if the tubular member15and the conducting wire6come into contact with each other.

It is preferable that, as shown inFIG.2: a proximal end portion of the tubular member15is located on the distal side relative to a distal end portion of the protective member13of the inner tube member12; and the distal end of the protective member13of the inner tube member12and the proximal end of the tubular member15are apart from each other. That is, it is preferable that: a space is present between the distal end of the protective member13of the inner tube member12and the proximal end of the tubular member15; and the inner tube member12is exposed from the protective member13in the lumen2of the outer tube member3. A distal end portion of the inner tube member12is preferably fixed to the inner wall of the outer tube member3. If the inner tube member12is exposed from the protective member13and the inner tube member12is fixed to the inner wall of the outer tube member3, the stiffness of a portion, of the outer tube member3, to which the distal end portion of the inner tube member12is fixed is increased, and the portion having an increased stiffness can be set as an origin from which the outer tube member3is to be bent. In addition, on the distal side of the outer tube member3, the location of the inner tube member12in the lumen2of the outer tube member3is fixed, and variation in the manner of bending, of the outer tube member3, that is caused by movement in the axial direction of the wire7disposed in the inner cavity of the inner tube member12is reduced, whereby the manner of the bending of the outer tube member3can be controlled to be uniform. In addition, if the inner tube member12is fixed to the inner wall of the outer tube member3, axial rotation (torque) of the catheter1applied on the hand side by an operator is easily transmitted to the outer tube member3through the inner tube member12, whereby the axial rotation of the distal end portion of the outer tube member3becomes easy to control.

Examples of a method for fixing the distal end portion of the inner tube member12to the inside of the lumen2of the outer tube member3include: a method in which an adhesive is caused to flow into the outer tube member3so as to fix the inner surface of the outer tube member3and the distal end portion of the inner tube member12to each other; a method in which a ring-shaped component or the like is attached on the outer tube member3at a location, at which the distal end portion of the inner tube member12is present in the inner cavity, and is crimped so that the outer tube member3and the distal end portion of the inner tube member12are fixed from the radially outward of the outer tube member3; and the like. Among the methods, the method in which an adhesive is caused to flow into the outer tube member3so as to fix the outer tube member3and the distal end portion of the inner tube member12to each other, is preferable. If the outer tube member3and the distal end portion of the inner tube member12are thus fixed to each other, the distal end portion of the inner tube member12can be easily and firmly fixed to the outer tube member3.

Examples of the adhesive used for fixing the distal end portion of the inner tube member12to the inside of the lumen2of the outer tube member3include epoxy resin-based adhesives, acrylic resin-based adhesives, urethane resin-based adhesives, and the like. Among the adhesives, an epoxy resin-based adhesive is preferably used. If such an adhesive is used, the adhesive is easily handled, and the distal end portion of the inner tube member12can be sufficiently fixed to the inside of the lumen2of the outer tube member3.

The inner tube member12is preferably fixed to the inside of the handle4. Specifically, the proximal end portion of the inner tube member12is preferably fixed to the inside of the handle4. If the inner tube member12is thus fixed, when a load such as a twist is applied to the outer tube member3, the load is less likely to be applied to the conducting wires6in the lumen2of the outer tube member3, whereby insulation property can be prevented from deteriorating owing to damage to the coatings of the conducting wires6, or the like.

Examples of a method for fixing the inner tube member12to the inside of the handle4include: methods that involve adhesion using an adhesive, welding in which a synthetic resin is melted and fixed, fixation using a separate member such as a screw, fitting of a recess and a projection, or the like; combinations of these methods; and the like. Among the methods, the fixation of the inner tube member12to the inside of the handle4is preferably performed by fitting the inner tube member12to the handle4. If the inner tube member12is thus fixed to the inside of the handle4, the inner tube member12can be easily and firmly fixed to the inside of the handle4.

A manufacturing method for the catheter1according to the present invention is a manufacturing method for the catheter1including: an outer tube member3having a lumen2extending in a longitudinal direction; a handle4provided on a proximal side of the outer tube member3; a plurality of electrodes5provided on a distal side of the outer tube member3; conducting wires6connected to one or more of the electrodes5and disposed in the lumen2and in the handle4, the conducting wires6each having a coating; an inner tube member12disposed in the lumen2; and a wire7having a proximal end portion disposed in an inner cavity of the handle4, and having a distal end portion fixed to a distal end portion of the outer tube member3. A connection point8abetween a one-side electrode5aand a conducting wire6aand a connection point8bbetween an other-side electrode5band a conducting wire6bare at different locations in a circumferential direction of the outer tube member3. The conducting wire6aconnected to the one-side electrode5aand the conducting wire6bconnected to the other-side electrode5bare disposed in the same lumen2of the outer tube member3. The manufacturing method includes: a first step of disposing the conducting wires6in the outer tube member3; and a second step of disposing at least one of the inner tube member12or the wire7in the outer tube member3. The second step is performed after the first step.

In the first step, the conducting wires6are disposed in the lumen2of the outer tube member3. The conducting wires6may be connected to the electrodes5and inserted into the holes10from a radially outward of the outer tube member3, to be disposed in the outer tube member3. Alternatively, the conducting wires6may be disposed in the outer tube member3and inserted into the holes10from a radially inner side of the outer tube member3, to be connected to the electrodes5. In particular, it is preferable that the conducting wires6are connected to the electrodes, and then the conducting wires6are inserted into the holes10of the outer tube member3, and the conducting wires6are disposed in the outer tube member3. If the first step is thus performed, connection between the conducting wires6and the electrodes5is easily performed, and workability can be improved.

In the second step, at least one of the inner tube member12or the wire7is disposed in the lumen2of the outer tube member3. Specific examples of the disposition include: a disposition in which an opening that allows communication with the lumen2is provided on the distal side or the proximal side of the outer tube member3, and at least one of the inner tube member12or the wire7is inserted through the opening; and the like. In particular, it is preferable that the inner tube member12and the wire7are disposed in the outer tube member3. In the case where both the inner tube member12and the wire7are disposed in the outer tube member3, the inner tube member12may be disposed in the outer tube member3, and then the wire7may be disposed in the inner tube member12. Alternatively, the wire7may be disposed in the inner tube member12, and then the inner tube member12, in the inner cavity of which the wire7has been disposed, may be disposed in the outer tube member3. In particular, it is preferable that the inner tube member12is disposed in the outer tube member3, and then the wire7is disposed in the inner tube member12. If the second step is thus performed, the inner tube member12and the wire7are easily disposed in the outer tube member3. Furthermore, damage to the coatings of the conducting wires6and a crack on the inner tube member12or the inner surface of the outer tube member3can be prevented from occurring by the inner tube member12and the wire7rubbing against the inner surface of the outer tube member3or the conducting wires6.

The second step is performed after the first step. If the conducting wires6having lower rigidities than the inner tube member12and the wire7and more likely to be damaged than the inner tube member12and the wire7are disposed in a state where the inner cavity of the outer tube member3is widest, the coatings of the conducting wires6can be prevented from being damaged. A separate step of, for example, providing the handle4on the proximal side of the outer tube member3may be performed between the first step and the second step.

A catheter according to the embodiment of the present invention includes: an outer tube member having a lumen extending in a longitudinal direction; a handle provided on a proximal side of the outer tube member; a plurality of electrodes provided on the outer tube member; conducting wires connected to one or more of the electrodes and disposed in the lumen, the conducting wires each having a coating; and a wire having a distal end portion fixed to a distal end portion of the outer tube member. A connection point between one of the electrodes and a conducting wire among the conducting wires and a connection point between another one of the electrodes and a conducting wire among the conducting wires are at different locations in a circumferential direction of the outer tube member. The conducting wire connected to the one of the electrodes and the conducting wire connected to the another one of the electrodes are disposed in the same lumen of the outer tube member. Accordingly, insulation property between the conducting wires to be subjected to application of voltages different from each other in polarity can be improved.

It is preferable that the above-described catheter further includes an inner tube member disposed in the lumen, the wire is disposed inside the inner tube member, and the inner tube member and the wire are disposed in the lumen in which the conducting wires are disposed. Accordingly, the wire and the conducting wires are disposed in different spaces in the lumen, whereby the insulation properties of the conducting wires can be prevented from deteriorating owing to contact between the wire and the conducting wires.

It is preferable that, in the above-described catheter, a distal side of the outer tube member bendable to one side by moving the wire in an axial direction, and in a cross section perpendicular to the axial direction of the outer tube member at a bending portion of the outer tube member, at least one position of at least one of the conducting wires is disposed on the one side among the one side and another side opposite to the one side of the outer tube member. Accordingly, a load is less likely to be applied to the conducting wires when the outer tube member is bent, whereby damage to the coatings of the conducting wires and breakage of the conducting wires can be prevented. Therefore, the insulation properties of the conducting wires can be maintained.

It is preferable that, in the above-described catheter, the conducting wire connected to the one of the electrodes and the conducting wire connected to the another one of the electrodes are at different locations in the circumferential direction of the outer tube member. Accordingly, the insulation properties of the conducting wires can be prevented from deteriorating owing to contact between the conducting wires.

It is preferable that, in the above-described catheter, the inner tube member has a protective member disposed at a radially outward of the inner tube member. In addition, the protective member of the inner tube member is preferably formed from an insulating material different from an insulating material of the coating of each of the conducting wire. Owing to these features, the insulation properties of the conducting wires can be prevented from deteriorating owing to contact between the inner tube member and the conducting wires.

It is preferable that, in the above-described catheter, the protective member of the inner tube member is formed from a polyolefin-based resin. In addition, the coating of each of the conducting wire is preferably formed from a fluorine-based resin. Owing to these features, the insulation properties of the conducting wires can be prevented from deteriorating owing to contact between the inner tube member and the conducting wires.

It is preferable that, in the above-described catheter, a thickness of the coating of each of the conducting wire is not smaller than 20 μm and not larger than 50 μm. Accordingly, the coating of the conducting wire becomes less likely to fall off. Furthermore, the conducting wires can be prevented from coming into contact with each other in the lumen by the conducting wires becoming thick more than necessary.

It is preferable that the above-described catheter further includes an elastic member having a distal end portion fixed to the distal end portion of the outer tube member and having a proximal end portion fixed to the inner tube member. Accordingly, it is possible to finely adjust the extent to which the distal side of the outer tube member is to be bent by moving the wire in the axial direction.

It is preferable that the above-described catheter further includes a tubular member provided on a proximal side relative to the distal end portion of the wire, and the wire and the elastic member are disposed in an inner cavity of the tubular member. Accordingly, the coatings of the conducting wires can be prevented from being damaged by the conducting wires coming into contact with another object such as the wire disposed in the lumen of the outer tube member.

It is preferable that, in the above-described catheter, a proximal end portion of the tubular member is on a distal side relative to a distal end portion of the protective member of the inner tube member, a distal end of the protective member of the inner tube member and a proximal end of the tubular member are apart from each other, and a distal end portion of the inner tube member is fixed to an inside of the lumen of the outer tube member. Accordingly, the stiffness of a portion, of the outer tube member, to which the distal end portion of the inner tube member is fixed is increased, and the portion having an increased stiffness can be set as an origin from which the outer tube member is to be bent. Therefore, the manner of the bending of the outer tube member becomes easy to adjust.

It is preferable that, in the above-described catheter, a proximal end portion of the inner tube member is fixed to an inside of the handle. Accordingly, when a load such as a twist is applied to the outer tube member, the load is less likely to be transmitted to the conducting wires, whereby insulation property can be prevented from deteriorating owing to damage to the coatings of the conducting wires, or the like.

It is preferable that, in the above-described catheter, the inner tube member is a coil or a pipe. Accordingly, it is possible to impart an appropriate flexibility while improving the rigidity of the outer tube member. Therefore, insertion of the catheter into a blood vessel is facilitated, and the catheter is easily inserted even into a curvy blood vessel.

A manufacturing method for a catheter according to the embodiment of the present invention is a manufacturing method for a catheter including: an outer tube member having a lumen extending in a longitudinal direction; a handle provided on a proximal side of the outer tube member; a plurality of electrodes provided on a distal side of the outer tube member; conducting wires connected to one or more of the electrodes and disposed in the lumen and in the handle, the conducting wires each having a coating; an inner tube member disposed in the lumen; and a wire having a proximal end portion disposed in an inner cavity of the handle, and having a distal end portion fixed to a distal end portion of the outer tube member. A connection point between one of the electrodes and a conducting wire among the conducting wires and a connection point between another one of the electrodes and a conducting wire among the conducting wires are at different locations in a circumferential direction of the outer tube member. The conducting wire connected to the one of the electrodes and the conducting wire connected to the another one of the electrodes are disposed in the same lumen of the outer tube member. The manufacturing method includes: a first step of disposing the conducting wires in the outer tube member; and a second step of disposing at least one of the inner tube member or the wire in the outer tube member. The second step is performed after the first step. Accordingly, each conducting wire, and the inner tube member and the wire, can be made less likely to come into contact with each other.

As described above, the catheter of the present invention includes: an outer tube member having a lumen extending in a longitudinal direction; a handle provided on a proximal side of the outer tube member; a plurality of electrodes provided on the outer tube member; conducting wires connected to one or more of the electrodes and disposed in the lumen, the conducting wires each having a coating; and a wire having a distal end portion fixed to a distal end portion of the outer tube member. A connection point between one of the electrodes and a conducting wire among the conducting wires and a connection point between another one of the electrodes and a conducting wire among the conducting wires are at different locations in a circumferential direction of the outer tube member. The conducting wire connected to the one of the electrodes and the conducting wire connected to the another one of the electrodes are disposed in the same lumen of the outer tube member. Owing to this configuration, the space through which the conducting wires and the like pass is wide in the inner cavity of the outer tube member, and thus multi-polarization of the catheter and reduction in the diameter thereof can be achieved, and bending of the distal end portion of the catheter can be finely controlled. In addition, even though the conducting wires are disposed in the same lumen of the outer tube member, the insulation properties of the conducting wires can be sufficiently ensured.

The present application claims the benefit of priority based on Japanese patent application number 2018-19459 filed on Feb. 6, 2018. The entire content of the specification of Japanese patent application number 2018-19459 filed on Feb. 6, 2018 is incorporated herein by reference.

DESCRIPTION OF REFERENCE SIGNS

1: catheter2: lumen3: outer tube member4: handle5: electrode5a: one-side electrode5b: other-side electrode6: conducting wire6a: conducting wire connected to one-side electrode6b: conducting wire connected to other-side electrode7: wire8a: connection point between one-side electrode and conducting wire8b: connection point between other-side electrode and conducting wire9: distal tip10: hole11: bending portion of outer tube member12: inner tube member13: protective member14: elastic member15: tubular memberS1: straight line passing center point of smallest circle circumscribing outer tube member and connection point between one-side electrode and conducting wireS2: straight line passing center point of smallest circle circumscribing outer tube member and connection point between other-side electrode and conducting wireθ1: angle between straight line S1and straight line S2