JP7701213B2 - Electrode Catheter - Google Patents

Description

The present invention relates to an electrode catheter used to measure electrical potentials of internal organs, primarily the heart, and to cauterize internal tissue.

Catheters with electrodes are sometimes used in the examination and treatment of arrhythmias such as atrial fibrillation. During examinations, an electrode catheter is inserted into the cardiac chambers and the intracardiac electrical potential is measured to identify the abnormal part of the heart that is causing the arrhythmia. During treatment, an ablation procedure is performed in which a high-frequency current is passed from the catheter's electrode to the myocardium causing the arrhythmia, cauterizing the source of the arrhythmia and electrically isolating it from the heart. Furthermore, if atrial fibrillation occurs during these examinations or treatments, it becomes difficult to measure and analyze the electrical potential within the heart, interfering with the examination or treatment, so defibrillation is performed by applying an electrical stimulus to the heart from the catheter's electrode.

For example, Patent Documents 1 to 4 disclose deflectable catheters in which lead wires connected to electrodes are disposed in the central lumen of a catheter tube whose inner surface is lined with a reinforcing tube.

JP 2000-288095 A JP 2005-144159 A Special Publication No. 2008-520281 JP 2009-148550 A

In an electrode catheter, signals are transmitted from or to the electrode through a conductor. In conventional electrode catheters such as those described above, the conductor can twist or vibrate in the catheter lumen during operation of the electrode catheter, such as when the electrode catheter is delivered to the lesion or when the distal part of the catheter is bent, causing noise in the signal transmitted by the conductor and reducing the signal-to-noise ratio. Therefore, the present invention aims to provide an electrode catheter that can suppress twisting and vibration of the conductor and reduce noise in the signal transmitted by the conductor.

One embodiment of the electrode catheter of the present invention that has been able to solve the above problems comprises an outer shaft having a distal end and a proximal end in the longitudinal direction and a lumen extending in the longitudinal direction, an inner shaft extending into the lumen of the outer shaft, one or more electrodes disposed in the distal portion of the outer shaft, and a first tubular member having a distal end and a proximal end in the longitudinal direction and a lumen extending in the longitudinal direction, the first tubular member being disposed in the lumen of the outer shaft and outside the inner shaft so that the inner shaft is disposed within the lumen of the first tubular member. The distal end of the first tubular member is located proximal to the proximal end of the electrode located most proximally among one or more electrodes, and has a conductor connected to the electrode and extending through the lumen of the outer shaft, outside the inner shaft, and into the lumen of the first tubular member, and in a cross section perpendicular to the longitudinal axis direction, the length between two points where a line passing through the centroid of the inner shaft intersects with the lumen wall of the first tubular member minus the length between two points where the line intersects with the outer wall of the inner shaft is three times or less than the major axis of the conductor. This configuration can suppress twisting and vibration of the conductor in the lumen of the catheter, thereby reducing noise in the signal transmitted from or to the electrode through the conductor.

In the longitudinal direction, the length of the first tubular member is preferably 50% or more of the length from the proximal end of the proximal-most electrode to the proximal end of the outer shaft.

In the longitudinal direction, it is preferable that the length from the proximal end of the electrode located most proximally to the distal end of the first tubular member is 5 times or less than the length from the distal end of the outer shaft to the proximal end of the electrode located most proximally.

The electrode catheter according to an embodiment of the present invention further includes a second tubular member disposed on the outside of the inner shaft, and it is preferable that the distal end of the first tubular member is located proximal to the distal end of the second tubular member.

The electrode catheter according to the embodiment of the present invention further has a second tubular member arranged on the outside of the inner shaft, and the distal end of the first tubular member is preferably located proximal to the proximal end of the second tubular member. In this case, in a cross section perpendicular to the longitudinal axis of the section in which the second tubular member is arranged in the longitudinal axis direction, the length obtained by subtracting the length between the two points where the line passing through the centroid of the inner shaft intersects with the lumen wall of the outer shaft from the length between the two points where the line intersects with the outer wall of the second tubular member is preferably three times or less than the major axis of the conductor. Furthermore, in this case, it is preferable that the length from the proximal end of the second tubular member to the distal end of the first tubular member in the longitudinal axis direction is two times or less than the length from the distal end of the outer shaft to the proximal end of the electrode arranged most proximally.

When the length from the distal end of the outer shaft to the distal end of the first tubular member in the longitudinal direction is d, the outer shaft and the first tubular member are not fixed to each other distal to point D of d on the proximal side of the distal end of the first tubular member, and it is preferable that the electrode catheter according to the embodiment of the present invention has a fixing portion where the outer shaft and the first tubular member are fixed to each other proximal to point D of the first tubular member.

It is preferable that the first tubular member is not fixed to the inner shaft.

It is preferable that the first tubular member extend proximally beyond the proximal end of the outer shaft.

The first cylindrical member is preferably made of at least one polymer or elastomer selected from the group consisting of polyolefin resins, polyamide resins, polyimide resins, polyester resins, polyurethane resins, vinyl chloride resins, silicone resins, polycarbonate resins, and aromatic polyether ketone resins.

The electrode catheter of the present invention can suppress twisting and vibration of the conductor wire in the lumen of the catheter, thereby reducing noise in the signal transmitted from the electrode or through the conductor wire to the electrode. This can improve the S/N ratio of the signal transmitted by the conductor wire.

1 illustrates a plan view of an electrode catheter according to one embodiment of the present invention. 2 is an enlarged longitudinal cross-sectional view of a portion II of the electrode catheter shown in FIG. 1 . 3 shows a cross-sectional view of the electrode catheter taken along line III-III in FIG. 2. 4 illustrates a modification of the cross-sectional view shown in FIG. 3 . 4 illustrates another modification of the cross-sectional view shown in FIG. 3 . 6 shows a cross-sectional view of the electrode catheter taken along line VI-VI in FIG. 2. 13 illustrates an enlarged longitudinal cross-sectional view of a distal portion of an electrode catheter according to another embodiment of the present invention. 8 illustrates a cross-sectional view of the electrode catheter taken along line VIII-VIII in FIG. 7. 13 illustrates an enlarged longitudinal cross-sectional view of a distal portion of an electrode catheter according to yet another embodiment of the present invention. 10 illustrates a cross-sectional view of the electrode catheter taken along line XX in FIG. 9. 1 illustrates a cross-sectional view of the electrode catheter taken along line XI-XI of FIG. 2. 12 illustrates a modification of the cross-sectional view shown in FIG. 11 .

The present invention will be described below based on the embodiments, but the present invention is not limited to the embodiments described below, and can of course be modified as appropriate within the scope of the intent described above and below, all of which are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to contributing to an understanding of the features of the present invention.

The electrode catheter according to an embodiment of the present invention comprises an outer shaft having a distal end and a proximal end in a longitudinal direction and having a lumen extending in the longitudinal direction, an inner shaft extending into the lumen of the outer shaft, one or more electrodes disposed in the distal portion of the outer shaft, and a first tubular member having a distal end and a proximal end in a longitudinal direction and having a lumen extending in the longitudinal direction, the first tubular member being disposed in the lumen of the outer shaft and outside the inner shaft such that the inner shaft is disposed within the lumen of the first tubular member, The distal end of the tubular member has a first tubular member located proximal to the proximal end of the electrode located most proximally among one or more electrodes, and a conductor connected to the electrode and extending through the lumen of the outer shaft, outside the inner shaft, and into the lumen of the first tubular member, and in a cross section perpendicular to the longitudinal axis direction, the length between the two points where a line passing through the centroid of the inner shaft intersects with the lumen wall of the first tubular member minus the length between the two points where the line intersects with the outer wall of the inner shaft is three times or less the major axis of the conductor.

By having the above configuration, the electrode catheter according to the embodiment of the present invention can define a conductor insertion passage between the outer surface of the inner shaft and the inner lumen wall of the first tubular member, and since the defined insertion passage has a width equal to or less than a predetermined size, it is possible to suppress twisting and vibration of the conductor and reduce noise in the signal transmitted from or to the electrode through the conductor. This improves the S/N ratio of the signal transmitted by the conductor.

With reference to Figures 1 to 12, an example of the configuration of an electrode catheter will be described. Figure 1 shows a plan view of an electrode catheter according to one embodiment of the present invention. Figure 2 shows a longitudinal cross-sectional view of the II portion of the electrode catheter shown in Figure 1, i.e., the distal portion, enlarged. In Figure 2, the two conductors may not necessarily be present on the same cross section, but are shown on the same cross section for convenience. Figure 3 shows a cross-sectional view of the electrode catheter taken along line III-III in Figure 2. Figures 4 and 5 show different modified examples of the cross-sectional view shown in Figure 3. Figure 6 shows a cross-sectional view of the electrode catheter taken along line VI-VI in Figure 2. Figure 7 shows a longitudinal cross-sectional view of the distal portion of an electrode catheter according to another embodiment of the present invention enlarged. Figure 8 shows a cross-sectional view of the electrode catheter taken along line VIII-VIII in Figure 7. Figure 9 shows a longitudinal cross-sectional view of the distal portion of an electrode catheter according to yet another embodiment of the present invention enlarged. Figure 10 shows a cross-sectional view of the electrode catheter taken along line X-X in Figure 9. FIG. 11 shows a cross-sectional view of the electrode catheter taken along line XI-XI in FIG. 2, and FIG. 12 shows a modified example of the cross-sectional view shown in FIG. 11. In this specification, the electrode catheter is sometimes simply referred to as a catheter.

In the present invention, the proximal side refers to the direction toward the user's hand in the extending direction of the electrode catheter 1, and the distal side refers to the opposite direction of the proximal side, i.e., the direction toward the subject of treatment. The extending direction of the electrode catheter 1 is preferably the same as the longitudinal axis direction x of the outer shaft 10. In a cross section perpendicular to the longitudinal axis direction x, the direction connecting the center of the outer shaft 10 and a point on the circumscribed circle of the outer shaft 10 is referred to as the radial direction y. In the figures in this specification, the left side of the figure is the distal side and the right side of the figure is the proximal side.

As shown in FIG. 1, the electrode catheter 1 has an outer shaft 10 having a distal end and a proximal end in the longitudinal axis direction x and an inner lumen extending in the longitudinal axis direction x. The distal end of the outer shaft 10 is inserted into the body, and the distal end is delivered to the treatment site by operating a handle or the like connected to the proximal end. For this reason, the outer shaft 10 is preferably flexible, and metal or resin can be used as a material. Since it is inserted into the body, the outer shaft 10 is preferably made of a biocompatible material.

As shown in FIG. 2, one or more electrodes 50 are disposed in the distal portion of the outer shaft 10. Although not shown, a component for testing or treatment other than the electrode 50, such as a sensor, may be disposed in the distal portion of the outer shaft 10. An internal structure for bending the distal portion of the catheter 1 may be disposed in the inner cavity of the outer shaft 10. Since the components as described above are disposed in the inner cavity of the outer shaft 10, it preferably has a cylindrical structure. The length in the longitudinal axis direction x, the outer diameter, the thickness, etc. of the outer shaft 10 can be selected to an appropriate size depending on the purpose of use.

Examples of materials that can be used to form the outer shaft 10 include synthetic resins such as polyolefin resins, such as polyethylene and polypropylene; polyamide resins, such as nylon; polyester resins, such as PET; polyimide resins; aromatic polyether ketone resins, such as PEEK; polyether polyamide resins; polyurethane resins; fluororesins, such as PTFE, PFA, and ETFE; vinyl chloride resins; and silicone resins, as well as natural rubber.

The outer shaft 10 having a cylindrical structure may be a hollow coil formed by winding one or more wires in a spiral shape, a hollow coil or a hollow body coated with resin on at least one of the inner and outer surfaces, a cylindrical resin tube, or a combination of these in the longitudinal axis direction x. The outer shaft 10 may have a single-layer structure or a multi-layer structure. Alternatively, a portion of the outer shaft 10 in the longitudinal axis direction x or in the circumferential direction may be made of a single layer, and the other portion may have a multi-layer structure. When the outer shaft 10 has a multi-layer structure, for example, the outer shaft 10 may have a structure in which a metal braid such as stainless steel, carbon steel, or nickel-titanium alloy is used as the intermediate layer of the resin tube constituting the outer shaft 10.

The tip portion 11 is preferably disposed at the distal end of the outer shaft 10. The tip portion 11 may be a separate member from the outer shaft 10, or may be formed as part of the same member. When the tip portion 11 is a separate member from the outer shaft 10, the tip portion 11 may have a portion inserted into the inner cavity of the outer shaft 10 or a portion protruding distally from the distal end of the outer shaft 10. When the tip portion 11 is formed as part of the outer shaft 10, the tip portion 11 may be formed by sealing the opening at the distal end of the outer shaft 10 by heat fusing the distal end of the outer shaft 10 or the like. The tip portion 11 may be a tip electrode.

The handle 7 is preferably disposed proximal to the outer shaft 10, and the proximal end of the outer shaft 10 is preferably fixed inside the handle 7. The proximal ends of the conductor 40 and wire 22, which will be described later and extend from the lumen of the outer shaft 10, are preferably disposed inside the handle 7. The handle 7 may be provided with a wire operating section 70 to facilitate the operation of the wire 22. By fixing the proximal end of the wire 22 to the wire operating section 70, the wire operating section 70 can be operated to pull or release the wire 22, thereby bending or returning the distal section of the catheter 1 to its original position.

The electrode catheter 1 has an inner shaft 20 extending into the lumen of the outer shaft 10. The inner shaft 20 may have a solid structure or a hollow structure. By having the inner shaft 20 in the lumen of the outer shaft 10, the rigidity of the outer shaft 10 can be increased, and the catheter 1 can be easily inserted into a blood vessel. In addition, by having the inner shaft 20 in the lumen of the outer shaft 10, the electrode catheter 1 can transmit a force applied from the proximal side of the catheter 1 to the distal side, and the distal part of the catheter 1 can be curved to make it a deflectable catheter.

When the inner shaft 20 has a hollow structure, it is preferable that the inner shaft 20 is a tube or pipe having a cylindrical structure, or a hollow coil formed by winding one or more wires in a spiral shape. In particular, the inner shaft 20 is preferably a coil or a pipe, or a combination of these. If the inner shaft 20 has such a configuration, it is possible to increase the rigidity of the outer shaft 10 while imparting appropriate flexibility, resulting in a catheter 1 that can be easily inserted into a blood vessel and can easily deliver the distal part of the catheter 1 to a lesion even in a curved blood vessel.

The outer diameter of the cross section perpendicular to the longitudinal axis direction x of the inner shaft 20 is not particularly limited, and may be a circle as shown in FIG. 3, an ellipse as shown in FIG. 4, or a combination of these. When the inner shaft 20 has a hollow structure, the inner cavity shape of the cross section perpendicular to the longitudinal axis direction x of the inner shaft 20 may also be a circle, an ellipse, or a combination of these, similar to the outer shape. When the inner shaft 20 has a hollow structure, an elastic member 21 or a wire 22, which will be described later, may be disposed in the inner cavity of the inner shaft 20, as shown in FIG. 5.

The inner shaft 20 may extend to the vicinity of the proximal end of the outer shaft 10. The inner shaft 20 may be made of the same material along the longitudinal axis x, or may have a configuration in which different materials are connected midway along the longitudinal axis x. The distal end of the inner shaft 20 may be located near the distal end of the outer shaft 10, or may be located proximal to the distal end of the outer shaft 10. When the distal end of the inner shaft 20 is located proximal to the distal end of the outer shaft 10, for example, the catheter 1 may have a configuration in which the distal end of the inner shaft 20 is the base end of the curve and the distal side is bendable.

The material for the inner shaft 20 may be a synthetic resin, metal, etc., similar to that for the outer shaft 10. The inner shaft 20 may have a single-layer structure, or a multi-layer structure similar to that for the outer shaft 10. The material for the inner shaft 20 may be the same as or different from that for the outer shaft 10. The inner shaft 20 is preferably a metal, and more preferably a coil formed by winding a stainless steel wire in a spiral shape. Alternatively, the inner shaft 20 is preferably configured such that the proximal side is configured as a metal or resin tube, and a metal coil is connected to the distal side of the tube. If the inner shaft 20 has such a configuration, it is easy to make the distal part of the electrode catheter 1 deflectable while providing sufficient rigidity to the outer shaft 10.

As shown in FIG. 5 and in FIGS. 9 and 10 as other embodiments of the electrode catheter 1 described later, a wire 22 extending in the longitudinal axis direction x may be disposed in the lumen of the inner shaft 20. The wire 22 may be one or more. The distal portion of the electrode catheter 1 can be curved by pulling the wire 22 proximally. Alternatively, the distal portion of the electrode catheter 1 may be curved by pushing the wire 22 distally. The distal portion of the wire 22 is preferably connected or fixed to the distal portion of the electrode catheter 1, preferably to the distal portion of the elastic member 21 described later, and the proximal portion of the wire 22 is preferably connected or fixed to the wire operating unit 70.

The wire 22 may be, for example, a metal wire such as stainless steel, carbon steel, or nickel-titanium alloy, or a wire made of a synthetic resin such as polyamide resin, polyolefin resin, polyester resin, aromatic polyether ketone resin, polyimide resin, or fluororesin.

In order to adjust the degree of curvature of the distal portion of the electrode catheter 1, an elastic member 21 is preferably provided. The elastic member 21 may extend into the lumen of the inner shaft 20 as shown in FIG. 5, or the proximal end of the elastic member 21 may be connected to the distal end of the inner shaft 20 as shown in FIG. 9, which will be described later, as another embodiment. Examples of the elastic member 21 include a leaf spring and a coil spring. The distal end of the elastic member 21 is preferably fixed to the distal end of the outer shaft 10, preferably to the tip 11. The method of connecting the elastic member 21 to another member is not particularly limited, but may include brazing such as soldering, welding, bonding with an adhesive, and crimping. For the material constituting the elastic member 21, the description of the material constituting the wire 22 can be referred to.

One or more electrodes 50 are disposed on the distal portion of the outer shaft 10. As shown in FIG. 2, the electrode 50 is preferably disposed on the outside of a side hole provided on the distal portion of the outer shaft 10 so that the outer and inner sides of the outer shaft 10 penetrate through the electrode 50. The electrode 50 functions as a measurement electrode or a reference electrode when measuring the potential. The shape of the electrode 50 may be, for example, a ring shape, a ring with a cut in the cross section having a C-shape, or a coil shape formed by winding a wire. The electrode 50 can be disposed on the outer shaft 10 by crimping the electrode 50 to the outer shaft 10. Alternatively, the electrode 50 may be a rectangular or square plate electrode formed independently in an island shape when viewed from the outside of the outer shaft 10. At least one of the inner surface and the outer surface of such a plate electrode may be curved so as to easily follow the curved surface of the surface of the outer shaft 10. Among them, the electrode 50 is preferably ring-shaped. Because the electrode 50 is ring-shaped, the area of the electrode 50 on the outer peripheral surface of the outer shaft 10 can be increased, making it easier to bring the electrode 50 into contact with the inner wall of the heart, etc.

The electrode 50 only needs to be conductive, and can be made of a metal or a mixture containing a resin and a metal. In particular, metals such as platinum, platinum-iridium alloy, stainless steel, and tungsten, or conductive resins, are preferably used as the material for the electrode 50. When the electrode 50 is made of conductive resin, it is preferable to mix a contrast agent such as barium sulfate or bismuth oxide into the electrode 50 so that it can be seen under X-ray fluoroscopy.

As shown in Figures 2 to 5, the electrode catheter 1 is a first tubular member 30 having a distal end and a proximal end in the longitudinal axis direction x and having an inner lumen extending in the longitudinal axis direction x, the first tubular member 30 being disposed in the inner lumen of the outer shaft 10 and outside the inner shaft 20 so that the inner shaft 20 is disposed within the inner lumen of the first tubular member 30, and the distal end of the first tubular member 30 is located proximal to the proximal end of the electrode 50 that is disposed most proximally among the one or more electrodes 50.

The first tubular member 30 is preferably made of an insulating material. The first tubular member 30 is preferably made of at least one polymer or elastomer selected from the group consisting of polyolefin resin, polyamide resin, polyimide resin, polyester resin, polyurethane resin, vinyl chloride resin, silicone resin, polycarbonate resin, and aromatic polyether ketone resin. Among them, the first tubular member 30 is preferably made of a polyolefin resin such as polyethylene. This improves the flexibility of the first tubular member 30, and the first tubular member 30 can flexibly determine the insertion passage 35 of the conductor 40 described later. In addition, the slipperiness of the conductor 40 relative to the first tubular member 30 is improved, and damage to the conductor 40 caused by the conductor 40 coming into contact with the first tubular member 30 during the manufacture and use of the electrode catheter 1 can be prevented.

A conductor 40 is connected to the electrode 50, and the conductor 40 passes through a side hole provided in the outer shaft 10 and extends into the inner cavity of the outer shaft 10, the outside of the inner shaft 20, and the inner cavity of the first tubular member 30. The conductor 40 electrically connects the electrode 50 to an external device of the catheter 1, such as an electrocardiograph. The conductor 40 is electrically connected to the electrode 50, and when two electrodes 50 are arranged in the longitudinal axis direction x as shown in FIG. 2, it is preferable that one conductor 40 is connected to each electrode 50. Although not shown, three or more electrodes 50 may be arranged, and further conductors 40 may be arranged according to the number of electrodes 50.

The conductor wire 40 may be any wire that is electrically conductive, such as copper wire, iron wire, stainless steel wire, piano wire, tungsten wire, nickel titanium wire, etc. Among these, stainless steel wire is particularly preferred because it is straight and rigid, making it easy to pass the conductor wire 40 through the side hole of the outer shaft 10, and because the connection between the conductor wire 40 and the electrode 50 is less likely to break.

The conductor 40 may be a solid wire or a twisted wire. The cross-sectional shape of the conductor 40 perpendicular to the longitudinal axis direction x may be, for example, a circle, an oval, a polygon, or a combination of these. Whether the conductor 40 is a solid wire or a twisted wire, and regardless of the cross-sectional shape, the major axis of the conductor 40 means the diameter of the circumscribed circle of the conductor 40 in the cross-section perpendicular to the longitudinal axis direction x. The major axis of the conductor 40 is not particularly limited, and is preferably 0.05 mm or more, more preferably 0.08 mm or more, and even more preferably 0.1 mm or more. For example, the major axis of the conductor 40 is preferably 0.3 mm or less, more preferably 0.2 mm or less, and even more preferably 0.15 mm or less.

The conductor 40 may have a coating material on the portions other than the ends connected to the electrodes 50, etc. This can prevent short circuits with adjacent members. For the material of the coating material of the conductor 40, please refer to the description of the resin material constituting the outer shaft 10.

The electrode 50 and the conductor 40 can be connected by methods such as laser welding, resistance welding, or bonding with an adhesive.

As shown in Figures 3 to 5, in a cross section perpendicular to the longitudinal axis direction x, the length L1 between two points where a straight line B passing through the centroid C of the inner shaft 20 intersects with the inner cavity wall of the first tubular member ₃₀ minus the length L2 between two points where the straight line B intersects with the outer wall of the inner shaft 20 is 3 times or less than the major axis of the conductor 40. The length _L1-2 is preferably 2.5 times or less than the major axis of the conductor 40, more preferably 2.2 times or less, and may be 2.1 times or less. With this configuration, the outer surface of the inner shaft 20 and the inner cavity wall of the first tubular member 30 can define the insertion path 35 of the conductor 40, and the defined insertion path 35 has a width of a predetermined size or less, so that twisting and vibration of the conductor 40 can be suppressed, and noise in a signal transmitted from the electrode 50 or through the conductor 40 to the electrode 50 can be reduced. This improves the S/N ratio of the signal transmitted by the conductor 40. 3 and 5, when the electrode catheter 1 has two conductors 40, the two conductors 40 can be arranged at positions offset from each other by, for example, ₁₈₀ ° in the circumferential direction of the inner shaft 20, and these conductors 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 35. Even when the electrode catheter 1 has three or more conductors 40, the three or more conductors 40 can be arranged at intervals in the circumferential direction of the inner shaft 20, and the conductors 40 can be arranged in the insertion passage 35 defined to have a width equal to or smaller than a predetermined size, and the plurality of conductors 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 35.

Also, the length L _1-2 may be 2 times or less, 1.5 times or less, or 1.2 times or less of the major axis of the conductor 40. If the upper limit of the length L _1-2 is within the above range, for example, as shown in FIG. 4, when the electrode catheter 1 has one conductor 40, the width of the insertion passage 35 for the conductor 40 can be set to a predetermined value or less, and the conductor 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 35. Even when the electrode catheter 1 has two or more conductors 40, the multiple conductors 40 can be arranged in the insertion passage 35 defined to have a width of a predetermined value or less by distributing the multiple conductors 40 in a biased manner in a part of the circumferential direction of the inner shaft 20, and the conductor 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 35. In this case, for example, the multiple conductors 40 may be arranged at an offset of 15°, 20°, or 30° in the circumferential direction of the inner shaft 20.

The length L _1-2 is preferably at least 1 time, and more preferably at least 1.1 times, the length of the conductor 40. If the lower limit of the length L _1-2 is within the above range, the conductor 40 can be easily inserted into the insertion passage 35.

Here, the centroid C of the inner shaft 20 is the centroid of the outer edge shape of the inner shaft 20 in a cross section perpendicular to the longitudinal axis direction x. Therefore, the centroid C can be determined in the same manner whether the inner shaft 20 has a solid structure as shown in Figures 3 and 4 or a hollow structure as shown in Figure 5.

4, when at least one of the outer surface of the inner shaft 20 and the lumen wall of the first tubular member 30 has a shape that is deviated from a perfect circle in a cross section perpendicular to the longitudinal axis direction x, the length _L1-2 cannot be uniquely determined by how to draw the straight line B. In this case, it is preferable that the length _L1-2 falls within the above range when the straight line B is drawn so that the length _L1-2 is maximized.

The thickness of the first tubular member 30 in the radial direction y is preferably thinner than the thickness of the outer shaft 10. This ensures the flexibility of the first tubular member 30, so that even if the insertion passage 35 of the conductor 40 curves accordingly when the electrode catheter 1 is transported through a curved blood vessel, the first tubular member 30 can easily follow the curve, making it easier to define the insertion passage 35 of the conductor 40 arranged on the outside of the inner shaft 20 with the first tubular member 30. In addition, because the flexibility of the first tubular member 30 can be ensured, damage to the conductor 40 can also be prevented.

The bending strength of the first tubular member 30 is preferably smaller than the bending strength of the outer shaft 10. This ensures the flexibility of the first tubular member 30, so that even if the insertion passage 35 of the conductor 40 curves accordingly when the electrode catheter 1 is transported through a curved blood vessel, the first tubular member 30 can easily follow the curve, making it easier to define the insertion passage 35 of the conductor 40 arranged on the outside of the inner shaft 20 with the first tubular member 30. Furthermore, because the flexibility of the first tubular member 30 can be ensured, damage to the conductor 40 can also be prevented.

It is preferable that no member other than the conductor 40 is inserted through the passage 35 for the conductor 40, which is defined by the outer surface of the inner shaft 20 and the inner wall of the first tubular member 30. This is preferable because it prevents the conductor 40 from becoming entangled with other members in the passage 35 and prevents other members from interfering with the insertion of the conductor 40.

As shown in Fig. 6, in a cross section perpendicular to the longitudinal axis direction x, the length L5 between two points where a line B passing through the centroid C of the inner shaft 20 intersects with the inner lumen wall of the outer shaft ₁₀ minus the length L2 between two points where the line B intersects with the outer wall of the inner shaft 20 is preferably at least twice the major axis of the conductor 40. The length _L5-2 is more preferably at least 2.5 times the major axis of the conductor 40, and even more preferably at least 3 times. The length _L5-2 is preferably at most 6 times the major axis of the conductor 40, more preferably at most 5 times, and even more preferably at most 4 times. If the length _L5-2 is within the above range, it becomes easy to manufacture the distal portion of the electrode catheter 1 so that the electrode 50 is disposed at the distal portion of the outer shaft 10 and the conductor 40 connected to the electrode 50 extends into the lumen of the outer shaft 10 through a side hole provided in the outer shaft 10.

3 to 5, it is preferable that length L5-2 be within the above range even in the section proximal to the distal end of first tubular member 30 in the longitudinal axis direction x. Even if length _L5-2 is within the above range in this section, in the embodiment of the present invention, by disposing first tubular member 30, insertion path 35 for conductor wire 40 can be defined and twisting _and vibration of conductor wire 40 can be suppressed.

Although not shown, in a cross section perpendicular to the longitudinal axis direction x, if at least one of the outer surface of the inner shaft 20 and the lumen wall of the outer shaft 10 has a shape that deviates from a perfect circle, the length _L5-2 cannot be uniquely determined by how to draw the straight line B. In this case, it is preferable that the length _L5-2 falls within the above range when the straight line B is drawn so that the length _L5-2 is maximized.

In the longitudinal axis direction x, the length of the first tubular member 30 is preferably 50% or more of the length from the proximal end of the electrode 50 located most proximally to the proximal end of the outer shaft 10, more preferably 70% or more, even more preferably 80% or more, and may be 100%, i.e., the proximal end of the first tubular member 30 is located at the same position as the proximal end of the outer shaft 10. Since the first tubular member 30 has a length in the longitudinal axis direction x or more than a predetermined length, the insertion passage 35 of the conductor 40 can be defined by the inner wall of the first tubular member 30 in a section of the length in the longitudinal axis direction x or more than a predetermined length, and twisting and vibration of the conductor 40 can be more effectively suppressed.

Alternatively, the first tubular member 30 may extend proximally beyond the proximal end of the outer shaft 10. This allows the lead 40 connected to an external device located proximally beyond the proximal end of the outer shaft 10 to be placed in the lumen of the first tubular member 30 up to the proximal end, preventing kinking and vibration throughout the entire lead 40.

In the longitudinal axis direction x, the length S1 from the proximal end of the electrode 50 arranged on the most proximal side to the distal end of the first tubular member 30 is preferably 5 times or less than the length S2 from the distal end of the outer shaft 10 to the proximal end of the electrode 50 arranged on the most proximal side. The length S1 is more preferably 3 times or less than the length S2, and even more preferably 2 times or less, and may be 1 time or less, 1/2 or less, or 1/3 or less. The lower limit of the length S1 is not particularly limited, and may be, for example, 1/10 or more, 1/8 or more, or 1/5 or more of the length S2. FIG. 6 shows a section between the proximal end of the electrode 50 arranged on the most proximal side and the distal end of the first tubular member 30 where the insertion path of the conductor 40 is not defined by the first tubular member 30. If the length S1 is within the above range, the section where the insertion path of the conductor 40 is not defined by the first tubular member 30 can be shortened, and twisting and vibration of the conductor 40 can be more easily prevented.

As shown in FIG. 7, the electrode catheter 1 further includes a second tubular member 60 disposed on the outside of the inner shaft 20, and the distal end of the first tubular member 30 is preferably located proximal to the distal end of the second tubular member 60. For example, the distal end of the second tubular member 60 may be disposed near the distal end of the inner shaft 20, and the proximal end of the second tubular member 60 may be disposed near the proximal end of the inner shaft 20, so that the second tubular member 60 overlaps with 80% or more, 90% or more, or 100% of the outer part of the inner shaft 20. By disposing the second tubular member 60 on the outside of the inner shaft 20, for example, even if the electrode catheter 1 is bendable and the inner shaft 20 is configured as a coil, the coil can be prevented from expanding outward in the radial direction y when the electrode catheter 1 is bent.

For the material constituting the second tubular member 60, please refer to the description of the material constituting the first tubular member 30. The second tubular member 60 may abut the outer surface of the inner shaft 20.

In the above configuration, as shown in Fig. 8, the insertion passage 35 for the conductor 40 can be defined by the outer surface of the second tubular member 60 and the inner cavity wall of the first tubular member 30. In this case, the width of the insertion passage 35 can be further narrowed from the length _L1-2 by the thickness of the second tubular member 60, so that twisting and vibration of the conductor 40 can be more easily prevented. However, since the second tubular member 60 is disposed on the outside of the inner shaft 20 having a certain rigidity, the second tubular member 60 cannot flexibly define the insertion passage 35 for the conductor 40 as the first tubular member 30 can, even if the second tubular member 60 has the same constituent material and thickness as the first tubular member 30. Therefore, for example, even if the first tubular member 30 is not provided and the insertion passage 35 of the conductor 40 is defined by the outer surface of the second tubular member 60 and the inner lumen wall of the outer shaft 10, the object of the present invention cannot be achieved. It is important in the present invention that the insertion passage 35 of the conductor 40 is defined by the inner lumen wall of the first tubular member 30.

As shown in FIG. 9, the electrode catheter 1 has a second tubular member 60 disposed on the outside of the inner shaft 20, and the distal end of the first tubular member 30 is preferably located proximal to the proximal end of the second tubular member 60. This allows the second tubular member 60 to be disposed on the distal end side of the inner shaft 20, and even if the electrode catheter 1 is bendable and the inner shaft 20 is configured as a coil, the distal portion of the inner shaft 20, which is the base end of the bend, can be prevented from expanding outward in the radial direction y when the electrode catheter 1 is bent.

10 , in the case of the above configuration, in a cross section perpendicular to the longitudinal axis direction x of the section in which the second tubular member 60 is disposed, a length L3-4 obtained by subtracting a length L4 between two points where the line B intersects with the outer wall of the second tubular member 60 from a length _L3 between two points where the line B passing through the centroid C of the inner shaft 20 intersects with the lumen wall of the outer shaft 10 is preferably three times or less the major axis of the conductor 40. In this case, the second tubular member 60 is preferably disposed in a section of length S1 from the proximal end of the electrode 50 disposed most proximally to the distal end of the first tubular member 30. Because the distal end of the first tubular member 30 is located proximal to the proximal end of the second tubular member 60, the insertion passage 65 of the conductor 40 is not defined by the first tubular member 30 in the section in which the second tubular member 60 is arranged in the longitudinal axis direction x. However, due to the above-mentioned configuration, the insertion passage 65 of the conductor 40 can be defined in this section by the outer surface of the second tubular member 60 and the inner lumen wall of the outer shaft 10, and since the defined insertion passage 65 has a width of a predetermined size or less, twisting and vibration of the conductor 40 can be suppressed even in the proximal section where the first tubular member 30 is not arranged, and noise in the signal transmitted from the electrode 50 or to the electrode 50 through the conductor 40 can be reduced.

The length L _3-4 is preferably 2.5 times or less, more preferably 2.2 times or less, and may be 2.1 times or less, of the major axis of the conductor 40. If the length L _3-4 is within the above range, the above effect can be achieved. In this case, as shown in FIG. 10, the conductor 40 may be one, or, although not shown, the conductor 40 may be two or more. When there are two conductors 40, for example, the conductors 40 can be arranged at positions shifted by 180° in the circumferential direction of the inner shaft 20, and these conductors 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 65. Even when the electrode catheter 1 has three or more conductors 40, the three or more conductors 40 can be arranged at intervals in the circumferential direction of the inner shaft 20, so that the conductors 40 can be arranged in the insertion passage 65 defined to a width of a predetermined size or less, and the multiple conductors 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 65.

Also, the length L _3-4 may be 2 times or less, 1.5 times or less, or 1.2 times or less of the conductor 40. If the upper limit of the length L _3-4 is within the above range, for example, as shown in FIG. 10, when the electrode catheter 1 has one conductor 40, the width of the insertion passage 65 for the conductor 40 can be set to a predetermined width or less, and the conductor 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 65. Even when the electrode catheter 1 has two or more conductors 40, the multiple conductors 40 can be arranged in the insertion passage 65 defined to a width of a predetermined width or less by distributing the multiple conductors 40 in a biased manner in a part of the circumferential direction of the inner shaft 20, and the conductor 40 can be prevented from twisting or vibrating in the radial direction y in the insertion passage 65. In this case, for example, the multiple conductors 40 may be arranged at 15°, 20°, or 30° offset from each other in the circumferential direction of the inner shaft 20.

The length L _3-4 is preferably at least 1 time, and more preferably at least 1.1 times, the length of the conductor 40. If the lower limit of the length L _3-4 is within the above range, the conductor 40 can be easily inserted into the insertion path 65.

Although not shown, in a cross section perpendicular to the longitudinal axis direction x, if at least one of the outer surface of the second tubular member 60 and the lumen wall of the outer shaft 10 has a shape that deviates from a perfect circle, the length _L3-4 cannot be uniquely determined by how to draw the straight line B. In this case, it is preferable that the length _L3-4 falls within the above range when the straight line B is drawn so that the length _L3-4 is maximized.

However, even if the length L _3-4 is within the above range, since the second tubular member 60 is disposed outside the inner shaft 20 having a certain rigidity, the second tubular member 60 cannot flexibly define the insertion passage 65 for the conductor 40 as the first tubular member 30 does, even if the second tubular member 60 has the same constituent material and thickness as the first tubular member 30. Therefore, the length of the longitudinal axis direction x of the insertion passage 65 defined by the second tubular member 60 is preferably short, and the length of the longitudinal axis direction x of the insertion passage 65 is preferably 5 times or less the length S2 from the distal end of the outer shaft 10 to the proximal end of the electrode 50 arranged on the most proximal side. The length of the longitudinal axis direction x of the insertion passage 65 is more preferably 4 times or less of S2, and even more preferably 3 times or less. Moreover, the length of the longitudinal axis direction x of the insertion passage 65 is preferably 1/2 or more of S2, and more preferably 1 time or more. This is preferable because it is possible to set the length of the insertion passage 65 defined by the second tubular member 60 in the longitudinal direction x to a certain value or less, and it is possible to insert the conducting wire 40 proximal to the proximal end of the second tubular member 60 into the insertion passage 35 defined by the first tubular member 30. The length of the insertion passage 65 in the longitudinal direction x in this embodiment can also be referred to as the length of the second tubular member 60 in the longitudinal direction x.

It is preferable that the conductor 40 is arranged at the same circumferential position of the inner shaft 20 in the insertion passage 35 and the insertion passage 65. This allows the conductor 40 to run in a straight line from the distal side to the proximal side.

In the longitudinal axis direction x, the length S3 from the proximal end of the second tubular member 60 to the distal end of the first tubular member 30 is preferably no more than twice the length S2 from the distal end of the outer shaft 10 to the proximal end of the electrode 50 located most proximally. The length S3 is more preferably no more than 1.5 times the length S2, even more preferably no more than 1 time, and may be no more than 4/5. The lower limit of the length S3 is not particularly limited, but may be, for example, 1/5 or more of S2, or 2/5 or more. As shown in FIG. 9, the section of length S3 is a section between the insertion passage 35 of the conductor 40 defined by the first tubular member 30 and the insertion passage 65 of the conductor 40 defined by the second tubular member 60. In this section, the insertion passage of the conductor 40 is not defined by either the first tubular member 30 or the second tubular member 60, and play occurs around the conductor 40. However, by setting the length S3 within the above range, the length of this section in the longitudinal axis direction x can be set to a predetermined length or less, making it easier to prevent twisting and vibration of the conductor 40.

As shown in Figures 2, 9, 11, and 12, when the length from the distal end of the outer shaft 10 to the distal end of the first tubular member 30 in the longitudinal axis direction x is d, it is preferable that the outer shaft 10 and the first tubular member 30 are not fixed to each other distal to point D of d on the proximal side of the distal end of the first tubular member 30, and that a fixing portion 31 is provided at which the outer shaft 10 and the first tubular member 30 are fixed to each other proximal to point D of the first tubular member 30.

Since the outer shaft 10 and the first tubular member 30 are not fixed to each other distally of the first tubular member 30, the distal side of the first tubular member 30 can move relative to the outer shaft 10, and the flexibility of the distal side of the first tubular member 30 can be ensured. Distal to the point D, the outer surface of the first tubular member 30 and the inner lumen wall of the outer shaft 10 may be in full or partial contact with each other as long as they are not fixed, but it is preferable that the outer surface of the first tubular member 30 and the inner lumen wall of the outer shaft 10 are not in contact with each other. With this configuration, even if the insertion passage 35 of the conductor 40 is curved following the curve when the electrode catheter 1 is transported through a curved blood vessel, the first tubular member 30 can easily follow the curve, and it becomes easier to define the insertion passage 35 of the conductor 40 arranged on the outside of the inner shaft 20 by the first tubular member 30. In addition, since it is easier to ensure the flexibility of the first cylindrical member 30, damage to the conductor 40 can be more easily prevented.

The first tubular member 30 has a fixing portion 31 that fixes the outer shaft 10 and the first tubular member 30 proximal to point D of the first tubular member 30, thereby preventing the first tubular member 30 from shifting in the longitudinal axis direction x or rotating in the circumferential direction. The fixing portion 31 is preferably provided by fixing using some kind of fixing means, such as bonding with an adhesive or welding with a resin.

The fixing portion 31 is preferably provided by fixing the inner wall of the outer shaft 10 and the outer surface of the first tubular member 30, and may be provided in one or more. When multiple fixing portions 31 are provided, it is preferable that the multiple fixing portions 31 are separated from each other. The fixing portion 31 may be provided over the entire circumferential direction of the outer peripheral surface of the first tubular member 30 as shown in FIG. 11. If the fixing portion 31 is provided over the entire circumferential direction, the fixing strength can be improved. Alternatively, the fixing portion 31 may be provided on a part of the circumferential direction of the outer peripheral surface of the first tubular member 30 as shown in FIG. 12. If the fixing portion 31 is provided on a part of the circumferential direction, it is easy to ensure the flexibility of the first tubular member 30 even in the part where the fixing portion 31 is provided.

In the longitudinal axis direction x, the length of the fixing portion 31 is not particularly limited, but the length of one fixing portion 31 is preferably at least 1/2 the length of one electrode 50, and more preferably at least 1 time. This improves the fixing strength. Also, in the longitudinal axis direction x, the length of one fixing portion 31 is preferably at most 1 time the length S1 from the proximal end of the electrode 50 located on the proximal side to the distal end of the first tubular member 30, and more preferably at most 1/2. This improves the flexibility of the first tubular member 30.

It is preferable that the first tubular member 30 is not fixed to the inner shaft 20. The first tubular member 30 is not fixed to the inner shaft 20, which is preferable because it improves the flexibility of the first tubular member 30. In addition, if the first tubular member 30 is fixed to the inner shaft 20, a fixing portion would be provided in the insertion passage 35 of the conductor 40 between the outer surface of the inner shaft 20 and the inner cavity wall of the first tubular member 30, and the conductor 40 would also be fixed. However, since the first tubular member 30 is not fixed to the inner shaft 20, the conductor 40 can be easily inserted into the insertion passage 35, and even if the electrode catheter 1 is curved, for example, the conductor 40 is not pulled by the fixation, making it easier to maintain the flexibility of the catheter 1.

The inner shaft 20 may be fixed to the outer shaft 10 on the distal side of the distal end of the first tubular member 30 in the longitudinal axis direction x. This can suppress the rotation of the inner shaft 20. Alternatively, the inner shaft 20 may be fixed to the first tubular member 30 on the proximal side of the distal end of the first tubular member 30 in the longitudinal axis direction x, and indirectly fixed to the outer shaft 10. In this case, the inner shaft 20 and the first tubular member 30 may also be fixed to the conductor 40, or the inner shaft 20 and the first tubular member 30 may be fixed at a portion where the conductor 40 is not arranged. In the above, the inner shaft 20 may be indirectly fixed to the first tubular member 30 and/or the outer shaft 10 via the second tubular member 60.

1: Electrode catheter 7: Handle 10: Outer shaft 11: Tip 20: Inner shaft 21: Elastic member 22: Wire 30: First tubular member 31: Fixation part 35: Conductor insertion passage 40: Conductor 50: Electrode 60: Second tubular member 65: Conductor insertion passage B: Straight line passing through the centroid of the inner shaft C: Centroid of the inner shaft d: Length from the distal end of the outer shaft to the distal end of the first tubular member D: Point d on the proximal side from the distal end of the first tubular member S1: Length from the proximal end of the electrode located on the most proximal side to the distal end of the tubular member S2: Length from the distal end of the outer shaft to the proximal end of the electrode located on the most proximal side S3: Length from the proximal end of the second tubular member to the distal end of the second tubular member x: Longitudinal axis direction y: Radial direction

Claims (10)

an outer shaft having a distal end and a proximal end in a longitudinal direction and having a lumen extending in the longitudinal direction;
an inner shaft extending through a lumen of the outer shaft;
one or more electrodes disposed on a distal portion of the outer shaft;
a first tubular member having a distal end and a proximal end in the longitudinal direction and having an inner lumen extending in the longitudinal direction, the first tubular member being disposed within the lumen of the outer shaft and outside the inner shaft such that the inner shaft is disposed within the lumen of the first tubular member, the distal end of the first tubular member being located proximal to a proximal end of a most proximal electrode of the one or more electrodes;
a conducting wire connected to the electrode and extending through a lumen of the outer shaft, outside the inner shaft, and into a lumen of the first tubular member;
a second tubular member disposed outside the inner shaft ,
a distal end of the first tubular member is located proximal to a distal end of the second tubular member;
An electrode catheter, in which, in a cross section perpendicular to the longitudinal axis direction, the length between two points where a line passing through the centroid of the inner shaft intersects with the inner lumen wall of the first tubular member minus the length between two points where the line intersects with the outer wall of the inner shaft is less than three times the major axis of the conductor. The electrode catheter according to claim 1, wherein the length of the first tubular member in the longitudinal axis direction is 50% or more of the length from the proximal end of the most proximal electrode to the proximal end of the outer shaft. An electrode catheter according to claim 1 or 2, wherein the length from the proximal end of the most proximal electrode to the distal end of the first tubular member in the longitudinal axis direction is 5 times or less than the length from the distal end of the outer shaft to the proximal end of the most proximal electrode. 4. The electrode catheter according to claim 1, wherein the distal end of the first tubular member is located proximal to the proximal end of the second tubular member. 5. The electrode catheter according to claim 4, wherein in a cross section perpendicular to the longitudinal direction of a section in which the second tubular member is disposed in the longitudinal direction, a length obtained by subtracting a length between two points where a line passing through the centroid of the inner shaft and an inner lumen wall of the outer shaft intersect with the line and an outer wall of the second tubular member is three times or less than a major axis of the conductor. 6. The electrode catheter according to claim 4 or 5, wherein the length from the proximal end of the second tubular member to the distal end of the first tubular member in the longitudinal axis direction is less than or equal to twice the length from the distal end of the outer shaft to the proximal end of the electrode located most proximally . 7. The electrode catheter according to claim 1, wherein, when a length from the distal end of the outer shaft to the distal end of the first tubular member in the longitudinal axis direction is d, the outer shaft and the first tubular member are not fixed to each other distal to a point D that is a distance d from the distal end of the first tubular member proximally, and the electrode catheter further comprises a fixing portion at which the outer shaft and the first tubular member are fixed to each other proximally of the point D of the first tubular member. The electrode catheter according to any one of claims 1 to 7 , wherein the first tubular member is not fixed to the inner shaft. The electrode catheter according to any one of claims 1 to 8 , wherein the first tubular member extends proximally beyond the proximal end of the outer shaft. The electrode catheter according to any one of claims 1 to 9, wherein the first tubular member is composed of at least one type of polymer or elastomer selected from the group consisting of polyolefin-based resins, polyamide-based resins, polyimide-based resins, polyester-based resins, polyurethane-based resins, vinyl chloride-based resins, silicone-based resins, polycarbonate -based resins, and aromatic polyether ketone-based resins.

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