Electrode catheter

Abstract

The purpose of the present invention is to provide an electrode catheter for which the repeatability of a movement shape is high even when the load changes, and which can realize a movement shape with a high degree of freedom with respect to the shape of a measurement site. Provided is an electrode catheter comprising a catheter body, an operation handle connected to the base end side of the catheter body, and a tip section connected to the tip side of the catheter body, wherein the tip section comprises: an outer tube provided so as to separate a plurality of electrodes on the outer circumferential surface; a linking shaft that links a plurality of pieces in a hollow section of the outer tube so that the pieces are mutually rotatable within a prescribed range; a front member that is linked to the tip of the linking shaft; and a plurality of operation wires, one end of each of which is fixed to the front member and the other end of each of which is fixed to the operation handle. The electrode catheter, wherein: the pieces comprise a rotation shaft that projects in a direction orthogonal to the center of the linking shaft, a bearing hole that pivotably supports the rotational shaft, and a through hole that is provided at a position offset from the shaft center; and one of the operation wires is inserted into the through hole, and the tip section is set so as to be capable of bending.

Description

[Technical Field]

[0001] The present invention relates to a minimally invasive electrode catheter that is capable of bending near the tip of the catheter. [Background technology]

[0002] Various electrode catheters have been used as medical devices for diagnosing or treating cardiac arrhythmia. For example, as shown in Figures 9 to 12, there is an electrode catheter 100 that can be bent by bending a tip section 102 of the catheter. Figure 10 is a partial longitudinal cross-sectional view of the catheter main body 101, Figure 11 is a transverse cross-sectional view of the catheter main body 101 as viewed from the arrow XX in Figure 10, and Figure 12 is a longitudinal cross-sectional view of the tip section 102. This electrode catheter includes a flexible tubular catheter main body 101, a tip section 102 connected to the distal end of the catheter main body, an operating handle 103 connected to the proximal end of the catheter main body, and a plurality of puller wires 104 whose proximal ends are fixed to the operating handle and whose distal ends are fixed to the tip section (see Patent Document 1).

[0003] The catheter body 101 is flexible and can be bent, but cannot be compressed in the longitudinal direction, so that when the operating handle is rotated, the tip portion rotates correspondingly.

[0004] The tip section 102 has a tubular section 105 made of synthetic resin that is more flexible than the catheter body, and inside it is a deflection structure 106 that applies a bias to cause deflection. The deflection structure is a flat band-like body made of a flexible metal. The use of such a metal band forms an axis of shape, preventing shape change (so-called thermal sagging) that occurs over time while the catheter is placed in the heart.

[0005] The tip section tubing 105 has multiple off-axis lumens 107, positioned diametrically opposite each other across the flexible structure. Each of these opposing lumens accommodates a puller wire 104 for deflecting the tip section. The tubing also has another lumen 108 for carrying the tip section electrode lead wires 111. The tubing has an outer diameter equal to the outer diameter of the catheter body, 8 French (approximately 2.7 mm) or less. A tip electrode 109 is attached to the distal end of the tip section. Multiple ring electrodes 110 are attached along the longitudinal axis of the tip section. Individual electrode lead wires 111 are connected to the tip electrode and ring electrodes. Each lead wire runs through the tip section lumen 108, the central lumen 112 of the catheter body, and the operating handle, and connects to a connector 113 at the end of the operating handle. This connector can be used to connect an appropriate monitor, power source, and other necessary equipment. Because there is no internal axis, the shape is prone to change over time after it is placed in the heart, known as thermal sagging.

[0006] Two puller wires 104 extend from the operating handle, pass through a central lumen 112 in the catheter body, and are inserted into an off-axis lumen 107 in the tip section. The proximal end of each puller wire is fixed to the operating handle, and the distal end of each puller wire is fixed to a tip electrode 109. Two compression coils 114 are provided inside the catheter body, surrounding each puller wire. This structure allows the tip section to bend in both directions by operating the operating handle. That is, when either puller wire is moved in the longitudinal direction relative to the catheter body, the tip section bends toward the side of the tip section to which that puller wire is fixed, thereby bending the tip section (see paragraph 0040 of Patent Document 1).

[0007] Furthermore, although not an electrode catheter, a similar medical instrument, an endoscope, uses the following bending portion: An endoscope bending portion includes a plurality of bending pieces that are connected together along the longitudinal axis direction and have abutment portions at ends facing the longitudinal axis direction that abut against each other and are rotatable relative to each other, the bending pieces being arranged in a row along the longitudinal axis direction, the bending pieces each having an inner circumferential surface and an outer circumferential surface formed around the longitudinal axis and an annular wall portion having a predetermined length along the longitudinal axis direction, and a through hole through which a traction wire that penetrates the wall portion in the longitudinal axis direction and rotates the bending piece is inserted, the bending portion including a plurality of wire insertion portions, each having a wall portion with a first wall thickness, thin-walled portions between the plurality of wire insertion portions around the longitudinal axis that have a second wall thickness thinner than the first wall thickness, and thick-walled portions at locations different from the thin-walled portions between the plurality of wire insertion portions around the longitudinal axis and that have a third wall thickness thicker than the second wall thickness (see paragraph 0021 and FIG. 2 of Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-255401 [Patent Document 2] International Publication No. 2018 / 146852 Summary of the Invention [Problem to be solved by the invention]

[0009] The electrode catheter described in Patent Document 1 above can bend the distal end of the catheter, but the curvature of the bend depends on the design curvature of the flexible structure, which must be designed to match the shape of the measurement site. To manage the deflection of the flexible structure at the distal end, two compression coils are used inside the catheter body, surrounding the first and second puller wires. However, when a load is applied to the outer tubing, this can cause distortion of the movable shape, resulting in problems with the reproducibility of the curvature. Furthermore, the compression coils must be manually attached one by one, which reduces workability. Furthermore, current catheters generally use a mechanism that pulls the puller wire to forcibly bend the tube, so shortening the bending distance of the tube increases the tensile load when the distal end is bent, and the technical limit for the bending radius is 2 cm.

[0010] Furthermore, in the bending portion of the above-mentioned Patent Document 2, although the curvature of the bending portion composed of bending pieces can be changed as a whole, since it is intended for use in an endoscope, there is no concept of changing the curvature to match the shape of the measurement site as in an electrode catheter. Therefore, there is no degree of freedom in setting appropriate curvatures that differ for each site, and there are problems with applying this bending portion configuration to an electrode catheter. Furthermore, the bending pieces of an endoscope have a hollow structure in order to insert forceps inside for their intended use, and are not designed to allow electrodes to be placed on the outer surface.

[0011] In view of the problems inherent in the prior art, the present invention aims to provide an electrode catheter that can be curved to a desired shape with high reproducibility and with a high degree of freedom, and that can be easily manufactured at low cost. [Means for solving the problem]

[0012] The present invention provides an electrode catheter comprising a catheter body, an operating handle connected to the proximal end of the catheter body, and a tip section connected to the distal end of the catheter body, wherein the tip section comprises an outer tube having a plurality of electrodes spaced apart on its outer circumferential surface, a connecting shaft having a plurality of links connected to the hollow section of the outer tube so as to be rotatable relative to one another within a predetermined range, a leading member connected to the distal end of the connecting shaft, and a plurality of operating wires, one end of which is fixed to the leading member and the other end of which is fixed to the operating handle, wherein the links have a rotating shaft protruding in a direction perpendicular to the axis of the connecting shaft, a bearing hole for supporting the rotating shaft, and a through hole disposed at a position offset from the axis, one of the operating wires being inserted through the through hole, and the operating wire can be operated by the operating handle to bend the tip section. The electrode catheter of the present invention may also be characterized in that a plurality of links having different axial dimensions are connected to one another in accordance with the shape of the measurement site. Furthermore, the electrode catheter of the present invention may be characterized in that a notch is provided on the outer surface of the bridge to form a gap between the bridge and the inner surface of the outer tube, and the lead wire of the electrode is arranged in the gap. [Effects of the Invention]

[0013] The electrode catheter of the present invention can be easily manufactured at low cost and can be curved to a desired shape with high reproducibility and flexibility, corresponding to the shape of the measurement site. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing the appearance of a first embodiment of an electrode catheter according to the present invention. [Figure 2] FIG. 1 is a longitudinal cross-sectional view showing the distal end of the electrode catheter of Example 1. [Figure 3] FIG. 2 is a cross-sectional view showing the tip of the electrode catheter of Example 1. [Figure 4] FIG. 2 is a perspective view of a bridge of the electrode catheter of Example 1. [Figure 5]FIG. 10 is a side view of the connecting shaft in a straight state. [Figure 6] FIG. 10 is a side view of the connecting shaft in a curved state. [Figure 7] FIG. 10 is a cross-sectional view of a tip portion having a bending point provided just before the leading member. [Figure 8A] FIG. 10 is a perspective view of a bridge of the electrode catheter of Example 2. [Figure 8B] FIG. 10 is a perspective view of a bridge of the electrode catheter of Example 2. [Figure 8C] FIG. 8B is a view taken along arrow Z in FIG. [Figure 9] FIG. 1 is a perspective view of the appearance of an electrode catheter according to the prior art. [Figure 10] FIG. 1 is a partial longitudinal cross-sectional view of a catheter body according to the prior art. [Figure 11] 1 is a cross-sectional view of a catheter body according to the prior art. [Figure 12] FIG. 1 is a longitudinal cross-sectional view of the distal end of a prior art electrode catheter. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, modes for carrying out the present invention will be described based on respective examples. [Example 1] FIG. 1 is an external perspective view showing a first embodiment of the electrode catheter of the present invention. FIG. 2 is a longitudinal cross-sectional view of the distal end of the electrode catheter of the present invention, and FIG. 3 is a transverse cross-sectional view of the distal end taken along the line AA in FIG. 2. The schematic configuration of the electrode catheter 1 of the present invention is substantially the same as that of the electrode catheter of the prior art, Patent Document 1. Specifically, the electrode catheter 1 comprises a flexible tubular catheter body 2, an operating handle 3 connected to the proximal end of the catheter body 2, and a flexible synthetic resin distal end portion 4 connected to the distal end of the catheter body 2. The operating handle 3 is identical to operating handles of the prior art, and therefore a description thereof will be omitted. Note that in the following description, specific dimensions are given for components in appropriate locations to facilitate understanding of their structure; however, the described specific dimensions do not limit or affect interpretation of the technical scope of the invention.

[0016] The outer tubular member 5 constituting the catheter body 2 is no different from tubular members of the prior art. The operating handle 3 is connected to the proximal end of the tubular member 5, and the tip section 4 is connected to the distal end of the tubular member 5. The tubular member 5 is made of a flexible synthetic resin material such as polyolefin, polyamide, polyether polyamide, or polyurethane. The internal structure of the catheter body 2 is significantly different from that of prior art electrode catheters. Specifically, unlike prior art catheters, the catheter body 2 does not have two compression coils surrounding multiple puller wires. Furthermore, a support shaft 7 with multiple lumens is disposed within the tubular member 5. The proximal end of the support shaft 7 is fixed to the operating handle 3, and the distal end of the support shaft 7 is connected to a connecting shaft 8 constituting the tip section of the catheter.

[0017] Next, we will explain the tip section 4, which is a characteristic feature of the electrode catheter of the present invention. The tip section 4 comprises an outer tube 10 having multiple ring electrodes 9 spaced apart on its outer circumferential surface, a connecting shaft 8 having multiple links 12 connected within a hollow section 11 of the outer tube 10 so that they can rotate relative to each other within a predetermined range, a leading member 13 connected to the tip of the connecting shaft 8, and multiple operating wires 14, 15, one end of which is fixed to the leading member 13 and the other end of which is fixed to the operating handle 3.

[0018] The outer tube 10 is made of a biocompatible synthetic resin material such as polyurethane or polyethylene. The outer diameter of the outer tube 10 is the same as the outer diameter of the catheter body 2, 8 French (approximately 2.7 mm) or less, and preferably 6 French (approximately 2.00 mm) or less. The outer tube 10 is made as a tube with greater flexibility than the catheter body 2. As shown in FIG. 2, multiple ring electrodes 9 are attached to the outer surface of the outer tube 10 at predetermined intervals in the longitudinal direction. Although only four ring electrodes 9 are shown in FIG. 2, the number of attached ring electrodes 9 is arbitrary. For example, 6 to 20 ring electrodes 9 may be attached, and preferably 8 to 12 ring electrodes 9. Each ring electrode 9 is fixed to the outer tube 10 using a curable adhesive. The ring electrodes are made of a metal material with good electrical conductivity, such as gold, platinum, or iridium, and are preferably made of platinum or its alloys, which provide excellent contrast to X-rays when the electrode catheter is in use. Side holes 16 are formed in the wall of the outer tube 10 at positions corresponding to the positions where the ring electrodes 9 are fixed. Lead wires 17 are connected to the inner circumferential surface of each ring electrode 9 at locations corresponding to the side holes 16. An insulating coated metal wire is used for the lead wires 17, and the coating is stripped only at the end connected to the ring electrode 9, with the metal core wire welded to the inner circumferential surface of the ring electrode 9. The lead wires 17 inserted into the side holes 16 are introduced into a gap 18 formed between the connecting shaft 8 and the inner wall of the outer tube 10, and then passed through the internal space of the catheter main body 2 to be connected to a connector 19 provided on the operating handle 3. The outer diameter of the coating of the lead wires 17 is not large, approximately 0.06 to 0.1 mm. However, in order to install multiple lead wires 17, the larger the space formed between the outer surface of the connecting shaft 8 and the inner circumferential surface of the outer tube 10, the easier it is to install multiple lead wires 17. For this reason, a notch 25 is provided on the outer peripheral surface of the bridge 12, which is a component of the connecting shaft 8, and a gap 18 having a generally crescent shape in cross section is formed between the bridge 12 and the inner peripheral surface of the outer tube 10. An operating wire 15 is also inserted into this gap 18, and one end of the operating wire 15 is fixed to the operating handle 3.

[0019] The connecting shaft 8 is made up of multiple pieces 12 of the same shape connected together so that they can rotate relative to each other within a predetermined range. As shown in Fig. 4, each piece 12, which is a component of the connecting shaft 8, includes a rotation shaft 21 protruding in a direction perpendicular to the longitudinal axis, a bearing hole 22 that supports the rotation shaft 21 of an adjacent piece, and an axial through-hole 23 disposed at a position offset from the axis.

[0020] The lower half 24 of the bridge 12 in the longitudinal direction has a notch 25 formed on one side of a cylindrical shape with an outer diameter of 1.7 mm. Furthermore, on both side surfaces perpendicular to the notch 25, short shafts 21 are formed protruding in a direction perpendicular to the longitudinal axis, and notched spaces 26 are formed around the short shafts 21. Specifically, the lower half 24 of the bridge 12 in the longitudinal direction has a central plate 27 formed perpendicular to the notch 25, and the short shafts 21 are formed protruding from both sides of the central plate 27. The dimension H from the center to the bottom end face of the short shaft 21 is 0.4 mm, and the thickness T of the central plate 27 is 0.7 mm. The peripheral side surfaces of the ends of the short shafts 21 are rounded. Furthermore, an axial through-hole 23 is formed at a position offset from the axis center.

[0021] A pair of support arms 28 are formed in the upper longitudinal half of the bridge 12, corresponding to the positions of the short shafts 21 of the lower half. The distance W between the pair of support arms 28 is 0.7 mm. This distance W corresponds to the thickness T of the central plate 27 but is slightly larger than the thickness T of the central plate 27. Each pair of support arms 28 is provided with a bearing hole 22 perpendicular to the longitudinal axis, with the inner diameter of the bearing hole 22 being slightly larger than the outer diameter of the short shaft 21. The distance W is 0.7 mm at the center of the bearing hole 22 but 0.71 mm at the upper end of the support arms 28. In other words, the inner surfaces of the pair of support arms 28 have gently sloping surfaces 29. This facilitates fitting the lower-half central plate 27 between the pair of support arms 28. The dimension L from the center of the bearing hole 22 to the upper end surface of the lower half is 0.55 mm.

[0022] As a result, in the connecting shaft 8 to which multiple links 12 are connected, a gap of 0.15 mm, which is the difference between dimensions L and H, exists between adjacent links 12. This allows the minor shafts 21 of adjacent links 12, supported by the bearing holes 22, to rotate within a predetermined range. The range of rotation is determined by the size of the gap. Figure 5 is a side view of the connecting shaft 8 when it is straight, and Figure 6 is a side view of the connecting shaft 8 when the left operating wire 14 is pulled toward the base end, bending the connecting shaft to the left. When the gap, which is the difference between dimensions L and H, is large, the rotation range increases, and the radius of curvature when the connecting shaft 8 is bent to the maximum can be reduced. Conversely, when the gap is small, the rotation range decreases, and the radius of curvature when the connecting shaft 8 is bent to the maximum can be increased. By connecting multiple links 12 with different axial dimensions in this manner, it is possible to achieve a movable shape with a high degree of freedom that corresponds to the shape of the measurement site.

[0023] The links 12 are injection-molded as a single unit using biocompatible synthetic resin materials, such as engineering plastics (e.g., polyacetal, polyethylene, ABS, nylon, and polyurethane), and super engineering plastics (e.g., PEEK, PPS, and PSU). This approach offers the advantage of easy mass production. The links 12 are connected by utilizing the elastic deformation of injection-molded products made of synthetic resin. Specifically, the center plate 27 of one of the two links 12 to be connected is inserted into the gap W on the inner surface of the support arm 28 of the other link 12. In this case, a gentle slope 29 is formed on the inner surface of the support arm portion 28 of the piece, and the circumferential side of the shaft end of the short shaft 21 provided on both sides of the central plate portion 27 of the other piece is rounded in an R-shape.Therefore, when the other piece is pushed in the longitudinal direction, the R-shaped portion formed on the circumferential side of the shaft end of the short shaft 21 temporarily widens the gap W on the inner surface of the support arm portion 28 of the piece through elastic deformation, making it possible to fit the short shaft 21 into the bearing hole 22.

[0024] The leading member 13 has a shape that extends slightly below the substantially hemispherical leading part, and is connected to the upper end of the connecting shaft 8. Therefore, it has a structure that allows it to be connected to the uppermost link that constitutes the connecting shaft 8. That is, the side of the leading member 13 is provided with a pair of short shafts 31 that fit into the bearing holes 22 of the uppermost link of the connecting shaft 8. In addition, the lower surface of the leading member 13 is provided with fixing holes 32 for inserting and fixing the operating wires 14, 15, and the ends of the operating wires 14, 15 are fixed to the fixing holes 32 with an adhesive.

[0025] Furthermore, as shown in FIG. 7 , a wire termination element 31 can be provided on the outer tubing 10 between the connecting shaft 8, which is composed of multiple links 12, and the leading end member 13, thereby positioning a bending point K just before the leading end member 13. This provides flexibility to the outer tubing 10 from the leading end member 13 to the wire termination element 31, potentially reducing the risk of cardiac tamponade. Furthermore, since there is no need to provide a structure for bending the distal end inside the outer tubing 10 between the leading end member 13 and the wire termination element 31, space is created for a shape-memory alloy, such as an NITI alloy, allowing for the placement of distal shapes such as ring, basket, and penta-ray shapes used in pulmonary vein arrhythmia measurement. The outer tubing 10 and the wire termination element 31 are bonded with an adhesive, and the operating wires 14 and 15 are fixed to the wire termination element 31. This configuration provides a bending point K at the position of the wire termination element 31, allowing the distal ends to be bent by manipulating the operating wires 14 and 15. In FIG. 7 , 32 denotes a paging electrode, and 33 denotes a paging wire.

[0026] The operation wires 14 and 15 can be any operation wire known in the art. That is, wires made of stainless steel, NITI, or the like, with a low-friction coating such as Teflon (registered trademark), can also be used. Engineering plastic materials such as polyether ether ketone can also be used. The diameter of the operation wires is preferably 0.1 to 0.4 mm.

[0027] According to the electrode catheter described above, the connecting shaft can be bent by operating the operating handle, and the flexible tip portion 4 attached to the connecting shaft can be bent with good reproducibility in accordance with the shape of the measurement site.

[0028] [Example 2] Example 2 is suitable for realizing a catheter with a smaller diameter than the electrode catheter of Example 1. In Example 1, for example, a catheter up to 6 French (approximately 2.0 mm) can be realized without difficulty, but it is not easy to realize a catheter of 5 French (approximately 1.67 mm) or less. Therefore, Example 2 is designed to easily realize even a small-diameter catheter by devising the shape of the link that constitutes the connecting shaft.

[0029] 8A, 8B, and 8C show the appearance of a bridge 12 used in the electrode catheter of Example 2, with FIG. 8A being a perspective view from the side without notch 25, FIG. 8B being a perspective view from the side with notch 25, and FIG. 8C being a view as seen from the arrow Z in FIG. 8A. This bridge 25 has the same basic configuration as the bridge in Example 1. That is, a notch 25 is provided on one side of a lower half 24 in the longitudinal direction of the bridge 12, and short shafts 21 protruding in a direction perpendicular to the longitudinal axis are provided on both side surfaces perpendicular to the notch 25. Furthermore, a notched space 26 is provided around the short shaft 21, and a central plate portion 27 is formed perpendicular to the notch 25. Furthermore, an axial through-hole 23 is provided at a position offset (e) from the longitudinal axis. Furthermore, a pair of support arms 28 are formed in the upper half of the bridge 12 at positions corresponding to the positions of the short shafts 21 of the lower half, and bearing holes 22 are formed in the pair of support arms 28 at positions perpendicular to the longitudinal axis. The bridge in Example 2 and the bridge in Example 1 have the same configuration as described above, but the bridge in Example 2 and the bridge in Example 1 differ in the following points.

[0030] The outer diameter of the bridge 12 in Example 2 is smaller than that of the bridge in Example 1. Specifically, the outer diameter of the bridge in Example 1 is 1.7 mm, while the outer diameter of the bridge in Example 2 is 1.3 mm. The offset (e) of the through hole 23 from the axis of the bridge in Example 2 is smaller than that of Example 1. Since a smaller outer diameter of the bridge results in a thinner wall around the bearing hole 22 in the support arm 28, the notch 25 of the bridge 12 in Example 2 is provided only in the lower half 24. The ends of the short shafts 21 formed on both sides of the center plate 27 are chamfered 30, forming downwardly inclined surfaces. Furthermore, the axial length of the center plate 27 of this bridge is larger than that of the bridge in Example 1, and the length of the upper half of the bridge is correspondingly larger. Therefore, the overall length of the bridge is relatively long compared to the outer diameter of the bridge.

[0031] By using this bridge, the outer diameter of the tip section 4 connected to the upper end of the connecting shaft 8 can be reduced, making it easy to realize an electrode catheter of 5 French (approximately 1.7 mm) or less. In addition, the end of the short shaft 21 is chamfered 30, which forms a sloped surface on the downward side, making it easy to connect the bridges by utilizing the elastic deformation of the support arm 28 of the connecting bridge.

[0032] The catheter of the present invention can be used for cardiac pacing and / or mapping in patients with cardiac disease, such as arrhythmias, heart failure, etc. When used for pacing and / or mapping, it can be used in the following manner, but is not limited to the following: 1. Make an incision in the skin over the femoral vena cava. 2. The catheter of the present invention is inserted into the femoral vena cava from the outside of the incision, and the electrode is placed in the lumen of the affected or unaffected part of the heart by tracing the vein from the femoral vena cava. 3. Connect the catheter terminal to a pulse generator or pacing system analyzer via an extension cable. 4. Pacing and / or mapping of affected or unaffected areas of the heart. 5. After pacing and / or mapping of the affected or unaffected part of the heart is completed, the catheter of the present invention is removed. 6. Suture the incision over the femoral vena cava.

[0033] Alternatively, for cardiac pacing and / or mapping, percutaneous puncture or incision of the subclavian or internal jugular vein can be used rather than the femoral vein. Typically, the left subclavian or right internal jugular vein is used.

[0034] As described above in detail, the electrode catheter of the present invention can bend its distal end to any or desired radius of curvature, allowing it to be inserted through curved blood vessel lumens. Furthermore, the electrode can be brought into accurate contact with the affected area of ​​the heart. This enables highly accurate and precise mapping and / or pacing of the affected area for the diagnosis and / or treatment of diseases such as arrhythmia and heart failure through electrophysiological testing.

[0035] The electrode catheter of the present invention can also be used as an ablation catheter in the treatment of arrhythmia, etc., and as an esophageal temperature sensor for preventing complications from injury due to esophageal overheating during cardiac ablation procedures.

[0036] Furthermore, the electrode catheter of the present invention can also be used as a defibrillation catheter which requires bending with a small radius of curvature in order to be placed in the coronary sinus.

[0037] While the present invention has been described above using examples, it is not limited to the above examples and various modifications are possible within the scope of the present invention. For example, the number, outer diameter, and length of the connecting shaft's components can be changed as needed. Furthermore, by connecting multiple types of connecting shafts with different distances from the center of the connecting shaft to the center of the bearing hole, the curvature of the tip can be partially changed. [Explanation of symbols]

[0038] 1 electrode catheter 2. Catheter body 3 Operating handle 4 Tip 8 Connecting shaft 9 electrodes (ring electrodes) 10 Exterior pipe 12 pieces 13 Leading member 14 Control wire 15 Control wire 17 Lead wire 18 Gap 21 Rotating shaft (short shaft) 22 Bearing hole 23 Through hole 25 Notch

Claims

1. An electrode catheter comprising a catheter body, an operating handle connected to a base end side of the catheter body, and a tip portion connected to a tip end side of the catheter body, the distal end portion comprises an outer tube having a plurality of electrodes spaced apart on its outer circumferential surface, a connecting shaft having a plurality of pieces connected within a hollow portion of the outer tube so as to be rotatable relative to one another within a predetermined range, a leading member connected to the distal end of the connecting shaft, and a plurality of operating wires each having one end fixed to the leading member and the other end fixed to the operating handle, The bridge includes a pivot shaft protruding from both sides of a central plate formed in a lower half of the connecting shaft in the longitudinal direction in a direction perpendicular to the shaft center, a bearing hole for supporting the pivot shaft in a pair of support arms formed in an upper half of the connecting shaft in the longitudinal direction, and a through hole disposed at a position offset from the shaft center, One of the operating wires is inserted through the through hole, An electrode catheter characterized in that the distal end portion can be bent by operating the operating wire with the operating handle.

2. 2. The electrode catheter according to claim 1, wherein a plurality of links having different axial dimensions corresponding to the shape of the measurement site are connected together.

3. 3. The electrode catheter according to claim 1, wherein a notch is provided on the outer peripheral surface of said piece to form a gap between said piece and the inner peripheral surface of said outer tube, and a lead wire of said electrode is disposed in said gap.

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