JP6063314B2 - Ablation catheter - Google Patents

Description

  The present invention relates to an ablation catheter preferably used for the treatment of arrhythmia and the like.

  As a method for treating tachyarrhythmia, catheter ablation using a catheter (generally called “ablation catheter”) is known. This treatment method is generally performed as follows. First, a long and flexible catheter shaft is inserted into a large blood vessel (eg, a femoral artery or a femoral vein) at the base of the foot, and its tip reaches the heart. Next, an electrocardiogram is measured while the electrode at the tip of the catheter shaft is in contact with the inner wall of the heart to search for an abnormal site. When an abnormal site is found, a high-frequency (RF wave) current is generated from the electrode at the tip of the catheter shaft, the myocardium in the deep part is cauterized, and the cells at the site (lesion) causing the arrhythmia are necrotized.

  In this catheter ablation, it is generally difficult to control the ablation area and the ablation depth. For example, if the high frequency current output is too high, the inner wall of the heart may be punctured, or the electrode temperature may increase and a thrombus may occur.

  A thermistor for measuring the surface temperature of the inner wall of the heart is provided at the distal end of the catheter shaft. When the surface temperature detected through the thermistor exceeds a preset dangerous temperature, it is common practice to prevent excessive cauterization by reducing the high-frequency current output.

  However, when the surface temperature control of the inner wall of the heart is performed, there is a problem that only the surface is cauterized and the deep lesion cannot be cauterized.

  Therefore, a technique for cauterizing deep lesions while cooling only the surface by cooling the inner wall surface of the heart has been studied.

  As one of the methods, there is a method using an irrigation catheter having a hole for blowing a physiological saline for cooling at the tip. However, in this method, the cooling effect varies depending on the orientation of the catheter shaft with respect to the inner wall surface of the heart, and the physiological saline is used. Since a pump is necessary, there is a problem that the apparatus is large and expensive.

  Patent Document 1 describes an ablation catheter that vibrates the distal end of a catheter shaft and cools the distal end of the catheter shaft by blood flow generated thereby. With this method, the above-mentioned problem of the irrigation catheter does not occur.

Japanese Patent No. 4582015

  Since the tip of the catheter shaft is inserted into the heart through a blood vessel, it is desirable that the catheter shaft has a small diameter. It is desirable to obtain the desired cooling effect by vibrating the tip of the catheter shaft without increasing the diameter of the tip of the catheter shaft.

  It is an object of the present invention to provide an ablation catheter having a catheter shaft having a small diameter and capable of vibrating its tip.

  The ablation catheter of the present invention includes a catheter shaft having an electrode for cauterizing a living tissue at a tip thereof, a vibration generating mechanism in which an electrode device including the electrode is mounted and housed in the catheter shaft, and the catheter shaft A rotation transmission wire which is rotatably housed therein, one end of which is connected to the vibration generating mechanism, and the other end which is led out from the end of the catheter shaft. The rotation transmission wire transmits the rotational motion input to the other end thereof to the vibration generating mechanism. The vibration generating mechanism swings due to the rotational movement of the rotation transmission wire. The electrode vibrates by the oscillation of the vibration generating mechanism.

  According to the present invention, the vibration generating mechanism on which the electrode device is mounted is housed in the catheter shaft, and the other end of the rotation transmission wire having one end connected to the vibration generating mechanism is led out from the end of the catheter shaft. Therefore, rotational movement can be input to the other end of the rotation transmission wire, and the vibration generating mechanism can be driven via the rotation transmission wire to vibrate the electrode. Since the rotational drive source that generates the rotational motion can be placed outside the catheter shaft, the constraints on the dimensions of the rotational drive source are relaxed. As a result, the desired cooling effect can be obtained by vibrating the tip electrode without increasing the diameter of the catheter shaft.

FIG. 1 is a perspective view of an ablation catheter according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the distal end of the catheter shaft of the ablation catheter according to the first embodiment of the present invention and the internal structure in the vicinity thereof. FIG. 3 is an exploded perspective view of the distal end of the catheter shaft of the ablation catheter according to the first embodiment of the present invention and the vicinity thereof. FIG. 4 is a perspective view of an electrode device and a vibration generating mechanism constituting the catheter shaft of the ablation catheter according to the first embodiment of the present invention. FIG. 5 is an exploded perspective view of the handle of the ablation catheter according to the first embodiment of the present invention. FIG. 6 is a plan view for explaining an operation of bending the catheter shaft so that the distal electrode faces a desired direction in the ablation catheter according to the first embodiment of the present invention. FIG. 7 is a perspective view showing the relationship between the vibration direction of the electrode and the sweep direction when cauterizing the ablation surface using the ablation catheter according to the first embodiment of the present invention. FIG. 8 is an exploded perspective view conceptually showing the configuration of the vibration generating mechanism built in the catheter shaft of the ablation catheter according to the second embodiment of the present invention. FIG. 9 is an exploded perspective view conceptually showing the structure of the vibration generating mechanism built in the catheter shaft of the ablation catheter according to Embodiment 3 of the present invention.

  Prior to the present invention, the present inventors have (1) a method for rotating an eccentric weight, (2) a method using a piezoelectric element, and (3) a method for bending a catheter shaft. The method of using the wire was examined.

  In method (1), an eccentric weight is housed at the tip of the catheter shaft, and the eccentric weight is rotated. As the mass of the eccentric weight and the amount of eccentricity are increased, the vibration energy generated is increased and the cooling effect is improved. However, it is difficult to accommodate an eccentric weight having a mass and an eccentric amount necessary for obtaining a desired cooling effect at the distal end of a catheter shaft having a small outer diameter.

  In the method (2), the stacked piezoelectric element is housed at the distal end of the catheter shaft. The tip of the catheter shaft is vibrated by applying a pulse voltage to the multilayer piezoelectric element to change the dimension of the multilayer piezoelectric element. However, since the dimensional change amount of the laminated piezoelectric element is generally small, the amplitude of vibration generated at the distal end of the catheter shaft is small, and it is difficult to obtain an effective cooling effect.

  In the method (3), in order to bend the catheter shaft and change the direction of its tip, a wire generally incorporated in the catheter shaft is alternately tensioned and relaxed at high speed. Thereby, the distal end of the catheter shaft can be bent and vibrated. Unlike the above methods (1) and (2), this method does not require a new mechanism for generating vibration at the distal end of the catheter shaft, so that the outer diameter of the distal end of the catheter shaft is reduced. Can do. However, since a common wire is used to perform both bending and vibration of the catheter shaft, in the state where the catheter shaft is bent by pulling the wire, even if the wires are alternately tensioned and relaxed, the tip of the catheter shaft Therefore, the amplitude of vibration generated in the filter becomes extremely small, and the desired cooling effect cannot be obtained.

  The present inventors examined a new method that can solve the problems of the above methods. As a result, a method of incorporating a vibration generating mechanism at the distal end of the catheter shaft and transmitting the rotational power from the outside of the catheter shaft to the vibration generating mechanism through the rotation transmission wire housed in the catheter shaft can achieve the above object. As a result, the present invention has been completed.

  The ablation catheter of the present invention includes a catheter shaft having an electrode for cauterizing a living tissue at a tip thereof, a vibration generating mechanism in which an electrode device including the electrode is mounted and housed in the catheter shaft, and the catheter shaft A rotation transmission wire which is rotatably housed therein, one end of which is connected to the vibration generating mechanism, and the other end which is led out from the end of the catheter shaft. The rotation transmission wire transmits the rotational motion input to the other end thereof to the vibration generating mechanism. The vibration generating mechanism swings due to the rotational movement of the rotation transmission wire. The electrode vibrates by the oscillation of the vibration generating mechanism.

  The ablation catheter of the present invention may further include a bending mechanism including at least one bending wire housed in the catheter shaft. In this case, when the at least one bending wire led out from the end of the catheter shaft is pulled, the bending mechanism may bend and deform the catheter shaft so that the electrode faces a desired direction. preferable. As a result, the catheter shaft of the present invention can be bent and deformed so that the electrodes face the desired direction with a simple structure. Further, since the vibration generating mechanism and the rotation transmission wire are mechanically independent from the bending mechanism, a stable cooling effect can always be obtained regardless of the bending state of the catheter shaft by the bending mechanism.

  In the above, a direction in which the electrode vibrates may be substantially perpendicular to a direction in which the catheter shaft is bent and deformed by the bending mechanism. Thus, when the catheter shaft is bent using a bending mechanism and the electrode is swept along the longitudinal direction with the electrode pressed against the surface to be ablated, the direction in which the electrode vibrates is determined by the method of the surface to be ablated. When viewed along the line direction, it can be made substantially orthogonal to the electrode sweep direction.

  The vibration generating mechanism is preferably disposed on the electrode side with respect to the bending mechanism. Thereby, it can prevent that a catheter shaft enlarges by providing a vibration generating mechanism.

  The vibration generating mechanism may include a hinge spring that can be elastically bent and deformed, a swinging head that is held by the hinge spring, and a crank pin that is displaced along a circular orbit by a rotational motion of the rotation transmission wire. . In this case, it is preferable that a groove extending in a direction perpendicular to the bending surface of the hinge spring is formed in the swing head. It is preferable that the crank pin is engaged with the groove of the swing head. As a result, a so-called Scotch yoke mechanism is configured, and a simple and highly reliable vibration generating mechanism that converts the rotational motion into the swing motion (vibration) of the swing head can be realized.

  The ablation catheter of the present invention may further include a handle that holds the distal end of the catheter shaft, and a rotational drive source that outputs a rotational motion for rotating the rotation transmission wire. In this case, the rotational drive source may be disposed outside the handle. This configuration is advantageous in reducing the size and weight of the handle gripped by the practitioner because the rotational drive source is not housed in the handle. In addition, restrictions on the size and weight of the rotary drive source are further relaxed, which is advantageous for further improving the cooling effect.

  The rotation transmission wire may be rotatably accommodated in the protective tube. In this case, the rotation transmission wire housed in the protective tube may be housed in the catheter shaft. This prevents the rotation transmitting wire from contacting other members in the catheter shaft regardless of the curvature of the catheter shaft. This is advantageous in obtaining a stable cooling effect because the rotational power loss of the rotation transmission wire is reduced.

  Below, this invention is demonstrated in detail, showing suitable embodiment. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of explanation, the drawings referred to in the following description show only the main members necessary for explaining the present invention in a simplified manner among the members constituting the embodiment of the present invention. Therefore, the present invention can include any member not shown in the following drawings. Further, in the following drawings, the actual dimensions of members and the dimensional ratios of the members are not faithfully represented.

(Embodiment 1)
FIG. 1 is a perspective view of an ablation catheter (hereinafter simply referred to as “catheter”) 1 according to Embodiment 1 of the present invention. The catheter 1 includes a handle 10 and a catheter shaft 20 held at one end of the handle 10 in the longitudinal direction. The handle 10 is a portion held by the practitioner and has a substantially bar shape as a whole. The catheter shaft 20 has the same length and outer diameter as a catheter shaft used in a conventional ablation catheter, and has flexibility to be freely curved. In order to simplify the drawing, in FIG. 1, an intermediate portion of the catheter shaft 20 that extends linearly along the longitudinal direction of the handle 10 is omitted. For convenience of the following description, an XYZ orthogonal coordinate system is set with the handle 10 and the axis parallel to the longitudinal direction of the catheter shaft 20 extended in a straight line as the Y axis. The Z axis is parallel to the rotation axis 12 (see FIG. 5, details will be described later) of the wire grip 15 provided on the handle 10. The electrode 27e side at the distal end of the catheter shaft 20 in the Y-axis direction is referred to as the “front” side or “tip” side, and the opposite side is referred to as the “rear” side or “end” side. Further, the Z-axis direction is referred to as “vertical direction”, and the direction orthogonal to the Z-axis (direction parallel to the XY plane) is referred to as “horizontal direction”. However, the “vertical direction” and “horizontal direction” do not mean the direction when the catheter 1 is used.

  In the catheter 1 of the first embodiment, the portion near the electrode 27e of the catheter shaft 20 (the bent portion 21 in FIG. 6) is indicated by arrows 21a and 21b so that the electrode 27e at the distal end of the catheter shaft 20 faces a desired direction. It can be bent in the horizontal direction. In addition, the electrode 27e of the catheter shaft 20 can be vibrated in the vertical direction in the direction of the arrow 22.

[Configuration of catheter shaft]
The configuration of the catheter shaft 20 will be described. FIG. 2 is a perspective view of the distal end of the catheter shaft 20 and the vicinity thereof. In FIG. 2, a two-dot chain line 25 is a cylindrical cover that covers the catheter shaft 20. FIG. 2 shows the members housed in the cover 25 as seen through. The catheter shaft 20 includes an electrode device 27, a vibration generating mechanism 30, and a bending mechanism 40 in this order from the distal end side. The cover 25 is made of a flexible material (for example, a resin material) like the conventional catheter, and seals members in the catheter shaft 20 including the vibration generating mechanism 30 and the bending mechanism 40 in a liquid-tight manner from the outside.

  FIG. 3 is an exploded perspective view of members housed in the cover 25 at and near the distal end of the catheter shaft 20. FIG. 4 is a perspective view of the electrode device 27 and the vibration generating mechanism 30 as seen from a direction different from those in FIGS. In FIG. 4, the bending mechanism 40 is removed for easy understanding.

  The electrode device 27 is provided at the distal end of the catheter shaft 20. The electrode device 27 includes an electrode 27e at the tip thereof for applying a high-frequency current to the living tissue and cauterizing it. The electrode 27e is exposed to the outside at the distal end of the catheter shaft 20 so as to be able to contact the living tissue. The electrode device 27 may include various sensors such as a pressure-sensitive sensor for detecting the presence or absence of a contact with a living tissue and a pressing force, a temperature sensor for detecting the ambient temperature, or the like. A known functional element may be provided in the ablation catheter.

  The vibration generating mechanism 30 that vibrates the electrode 27e of the catheter shaft 20 will be described. The vibration generating mechanism 30 according to the first embodiment includes a rotating shaft 31, a base 32, a swing head 33, and a hinge spring 34.

  The rotating shaft 31 includes an input shaft 31a, a shaft base 31b, and a crank pin 31c in this order from the rear side (the side opposite to the electrode device 27). The input shaft 31a is a rod-shaped member. The shaft base 31b has a cylindrical shape with a larger diameter than the input shaft 31a. The crank pin 31c is a rod-shaped member having a smaller diameter than the shaft base 31b. The input shaft 31a is coaxially connected to the shaft base 31b at the rear end of the shaft base 31b. On the other hand, the crank pin 31c is eccentrically connected to the front end of the shaft base 31b with respect to the input shaft 31a and the shaft base 31b.

  The base 32 has a substantially cylindrical shape. The base 32 is formed with two through holes 32a and 32b penetrating the base 32 in the axial direction (Y-axis direction). The input shaft 31a of the rotary shaft 31 is inserted into the bearing hole 32a which is one of the two through holes 32a and 32b, and the rotary shaft 31 is rotatably supported by the bearing hole 32a. The distal end of the input shaft 31 a of the rotating shaft 31 that protrudes rearward from the base 32 through the bearing hole 32 a is connected to the distal end of the rotation transmission wire 36 using the sleeve 35. The rotation transmission wire 36 is rotatably accommodated in a flexible protective tube 37. The protective tube 37 is made of, for example, a flexible resin material. The rotation transmission wire 36 and the protective tube 37 in which the rotation transmission wire 36 is accommodated are accommodated in the cover 25 of the catheter shaft 20.

  The oscillating head 33 has a substantially cylindrical shape having substantially the same outer diameter as the base 32. The oscillating head 33 is formed with a through hole 33b penetrating the oscillating head 33 in the axial direction (Y-axis direction). An electrode device 27 is mounted on the end surface of the oscillating head 33 opposite to the base 32.

  A hinge spring 34 connects the base 32 and the swing head 33. More specifically, the rear end of the hinge spring 34 is fixed to a flat fixing surface 32 c formed on the outer surface of the base 32, and the front end of the hinge spring 34 is fixed to a flat fixing surface formed on the outer surface of the swing head 33. It is fixed to the surface 33c. The hinge spring 34 is a strip-shaped thin plate, and its longitudinal direction coincides with the longitudinal direction of the catheter shaft 36, and its main surface (that is, the surface having the largest area) is arranged parallel to the XY plane. Has been. The hinge spring 34 can be elastically bent and deformed in a plane (YZ plane; hereinafter referred to as “bend plane”) that is parallel to the longitudinal direction and perpendicular to the main surface. When the hinge spring 34 is bent and deformed, the swing head 33 swings with respect to the base 32 within the bent surface of the hinge spring 34. The rotating shaft 31 is disposed to face the main surface of the hinge spring 34.

  As shown in FIG. 4, a groove (slot-shaped recess) extending along the direction (X-axis direction) perpendicular to the bent surface of the hinge spring 34 is formed on the end surface of the oscillating head 33 facing the base 32. 33a is formed. The crank pin 31c of the rotating shaft 31 is inserted into the groove 33a and engaged with the groove 33a.

  When the rotation transmission wire 36 is rotated in one direction (for example, clockwise direction R when viewed from the rear side), the rotation shaft 31 rotates in the same direction as the rotation transmission wire 36 in the bearing hole 32a of the base 32 via the sleeve 35. To do. Since the crank pin 31c is eccentric with respect to the rotation center axis of the rotary shaft 31, the crank pin 31c is displaced along a circular orbit centering on the rotation center axis of the rotation shaft 31. The crank pin 31 c is inserted into the groove 33 a of the swing head 33. Therefore, of the displacement along the circular orbit of the crank pin 31c, the displacement in the direction perpendicular to the longitudinal direction of the groove 33a (Z-axis direction) is transmitted to the oscillating head 33. That is, the crank pin 31c reciprocates in the groove 33a of the swing head 33 along the longitudinal direction (X-axis direction) of the groove 33a, while the swing head 33 is orthogonal to the groove 33a (Z-axis direction). Swing along. When the oscillating head 33 oscillates, the hinge spring 34 repeatedly bends and deforms elastically within its bending surface. As described above, the vibration generating mechanism 30 of the first embodiment has the same configuration as a so-called scotch yoke mechanism, and the rotational motion input from the rotation transmission wire 36 to the input shaft 31a of the rotating shaft 31 It is converted into 33 swinging motions. By continuously rotating the rotation transmission wire 36 at a constant rotational speed, the swing head 33 and the electrode device 27 vibrate in the up and down direction (in the direction of the arrow 22) at a constant cycle.

  As shown in FIG. 4, the through hole 33 b of the swing head 33 and the through hole 32 b of the base 32 are arranged along a common straight line. A wiring (not shown) connected to the electrode device 27 is inserted into the through hole 33 b and the through hole 32 b, accommodated in the cover 25 of the catheter shaft 20, and guided to the handle 10.

  In FIG. 4, in order to facilitate understanding, the rotation transmission wire 36 that actually extends into the handle 10 and the protective tube 37 that houses the rotation transmission wire 36 are cut along the way.

  Next, a bending mechanism 40 that bends the catheter shaft 20 so that the electrode 27e of the catheter shaft 20 faces a desired direction will be described. The bending mechanism 40 of the first embodiment includes a leaf spring 41 and a pair of bending wires 42a and 42b.

  As shown in FIGS. 2 and 3, the leaf spring 41 is a strip-like thin plate whose longitudinal direction coincides with the longitudinal direction of the catheter shaft 36 and whose main surface (that is, the area is maximum). Are arranged in parallel with the YZ plane. The leaf spring 41 can be elastically bent and deformed in a plane (XY plane; hereinafter referred to as “bend plane”) that is parallel to the longitudinal direction and perpendicular to the main surface.

  The bending wires 42a and 42b are arranged on both sides of the leaf spring 41. The tips of the wires 42 a and 42 b on the base 32 side are fixed at positions near the front end 41 a of the leaf spring 41. The method for fixing the wires 42a and 42b to the leaf spring 41 is not particularly limited, but for example, a welding method can be used.

  The front end 41 a of the leaf spring 41 is inserted into the through hole 33 b of the base 32, and the rear end 41 b is inserted into the guide tube 43. Steps are formed on both sides of the leaf spring 41 so that the portions of both ends 41a and 41b of the leaf spring 41 are slightly narrower than the portion between them. This step restricts the insertion depth of the leaf spring 41 with respect to the base 32 and the guide tube 43. The wires 42 a and 42 b are accommodated in the guide tube 43. The wires 42 a and 42 b and the guide tube 43 storing the wires 42 a and 42 b are stored in the cover 25 of the catheter shaft 20. It is desirable that the guide tube 43 has a high rigidity with respect to compression and torsion along the longitudinal direction in addition to the flexibility that allows the guide tube 43 to be freely curved.

  As shown in FIG. 2, the protection tube 37 that houses the rotation transmission wire 36 and the guide tube 43 that houses the wires 42 a and 42 b are housed in the cover 25. The opening at the tip of the cover 25 is liquid-tightly sealed by the electrode device 27.

[Composition of handle]
The configuration of the handle 10 will be described. FIG. 5 is an exploded perspective view of the handle 10.

  The upper case 11a and the lower case 11b are overlapped in the Z-axis direction to form the housing 11 of the handle 10. A substantially disc-shaped wire grip 15 is accommodated in the housing 11 of the handle 10. A support shaft 12 erected in parallel with the Z axis on the inner surface of the lower case 11 b passes through the central through hole of the wire grip 15. A pair of operation arms 15 a and 15 b protrude from the outer peripheral edge of the wire grip 15. The operation arms 15a and 15b extend along a straight line orthogonal to the support shaft 12, and project outside the housing 11 through notches formed in the upper case 11a and the lower case 11b, respectively (see FIG. 1). . The wire grip 15 can be rotated around the support shaft 12 by operating the operation arms 15a and 15b.

  The catheter shaft 20 is sandwiched between the upper case 11 a and the lower case 11 b and led out from the front end of the handle 10. From the end of the cover 25 of the catheter shaft 20, a protective tube 37 containing the rotation transmission wire 36 and bending wires 42 a and 42 b are led out.

  The protective tube 37 containing the rotation transmission wire 36 passes through the space between the wire grip 15 and the lower case 11b, is guided by the guide 13, and reaches the first connector 19a provided on the lower surface of the lower case 11b. ing. One end of the rotation transmission cable 14 is detachably connected to the first connector 19a, and the other end of the rotation transmission cable 14 is connected to a rotation drive source 38 (see FIG. 1). The configuration of the rotational drive source 38 is arbitrary as long as it can output rotational motion. For example, it can be configured by a motor as a power source and a gear mechanism that transmits power from the rotation shaft of the motor to the output end. The rotational drive source 38 may be controlled by the controller so that the rotational speed of the output rotational motion can be arbitrarily changed. The rotation transmission cable 14 has flexibility that can be freely bent, and transmits the rotation motion output from the rotation drive source 38 to the rotation transmission wire 36 via the first connector 19a.

  The bending wires 42 a and 42 b are fixed to the outer peripheral surface on the front side of the wire grip 15. The wire 42a is fixed to the wire grip 15 at a position close to the operation arm 15a, and the wire 42b is fixed to the wire grip 15 at a position close to the operation arm 15b.

  A male screw 12a is formed at the tip of the support shaft 12 that passes through the wire grip 15 and protrudes therefrom. A hole through which the support shaft 12 passes is formed in the upper case 11a. When the upper case 11a is superimposed on the lower case 11b, the male screw 12a of the support shaft 12 protrudes from the upper case 11a. A female screw (not shown) formed on the lower surface (surface on the wire grip 15 side) of the fixing knob 17 is screwed into the male screw 12 a of the support shaft 12. When the fixing knob 17 is turned and tightened to the male screw 12a, the wire grip 15 can be fixed by being sandwiched between the upper case 11a and the lower case 11b. When the fixing knob 17 is turned in the reverse direction, the fixing of the wire grip 15 by the upper case 11a and the lower case 11b can be released.

  A second connector 19 b is provided at the rear end of the handle 10. The wiring (not shown) connected to the electrode device 27 provided at the distal end of the catheter shaft 20 is led out from the end of the cover 25, passes through the space between the wire grip 15 and the lower case 11b, 2 is connected to the connector 19b. The power supply to the electrode 27e and the transmission and reception of electric signals to various sensors provided in the electrode device 27 are performed by electrically connecting the second connector 19b to a control device (not shown) via an electric cable (not shown). This is done by connecting to

[how to use]
A method of using the catheter 1 of Embodiment 1 will be described.

  The catheter 1 of Embodiment 1 can be used as follows, for example, similarly to the catheter of Patent Document 1 described above.

  First, the catheter shaft 20 is inserted into a thick blood vessel (for example, a femoral artery or a femoral vein) at the base of the patient's foot, and the electrode 27e at the tip thereof reaches the heart. In this process, like the conventional catheter, the catheter shaft 20 is appropriately bent so that the electrode 27e at the tip of the catheter shaft 20 faces a desired direction. In the catheter 1 of the first embodiment, the catheter shaft 20 is bent by operating a pair of operation arms 15 a and 15 b protruding from the handle 10.

  The operation of bending the catheter shaft 20 will be described with reference to FIG.

  FIG. 6 is a plan view of the catheter 1 with the upper case 11a and the fixing knob 17 removed for easy understanding.

  As shown in FIG. 6, when the direction connecting the pair of operation arms 15a and 15b is orthogonal to the longitudinal direction (Y-axis direction) of the handle 10, the bent portion 21 of the catheter shaft 20 is linear as shown by the solid line. It extends. Accordingly, the electrode 27e faces upward in FIG. 6 (the direction of the arrow on the Y axis).

  When the pair of operation arms 15a and 15b are operated in the direction of the arrow 16a to rotate the wire grip 15 in the clockwise direction, the wire 42a fixed to the side closer to the operation arm 15a of the two wires 42a and 42b. Is pulled slightly from the catheter shaft 20, and the opposite wire 42 b is loosened and pulled slightly into the catheter shaft 20. As described above, the tips of the wires 42a and 42b are fixed to different surfaces of the leaf spring 41, respectively. When the wire 42a is pulled, the leaf spring 41 bends so that the surface on the side to which the wire 42a is fixed becomes concave. Therefore, the portion (ie, the bent portion 21) in which the leaf spring 41 near the distal end of the catheter shaft 20 is built is bent in the direction of the arrow 21a as shown by the two-dot chain line 20a, and the electrode 27e is on the right side ( Face the arrow on the X axis). The bending angle of the catheter shaft 20 at the bending portion 21 can be adjusted by the rotation angle of the wire grip 15 (or the operation arms 15a and 15b) in the clockwise direction 16a.

  Contrary to the above, when the pair of operation arms 15a and 15b are operated in the direction of the arrow 16b to rotate the wire grip 15 in the counterclockwise direction, the two of the wires 42a and 42b are closer to the operation arm 15b. The side fixed wire 42b is pulled and slightly pulled out from the catheter shaft 20, and the opposite wire 42a is loosened and pulled slightly into the catheter shaft 20. Thereby, contrary to the above, the leaf spring 41 is bent so that the surface on the side where the wire 42b is fixed becomes concave. Accordingly, the portion (that is, the bent portion 21) in which the leaf spring 41 near the distal end of the catheter shaft 20 is built is bent in the direction of the arrow 21b as shown by the two-dot chain line 20b, and the electrode 27e is on the left side ( It faces the opposite side of the X-axis arrow. The bending angle of the catheter shaft 20 at the bending portion 21 can be adjusted by the rotation angle of the wire grip 15 (or the operation arms 15a and 15b) in the counterclockwise direction 16b.

  By turning the fixing knob 17 (see FIGS. 1 and 5) of the handle 10, the wire grip 15 is sandwiched between the upper case 11a and the lower case 11b, or the fixing can be released. For example, when the operation knobs 15a and 15b are operated to turn the fixing knob 17 in a state where the bent portion 21 of the catheter shaft 20 is bent to a desired angle, the wire grip 15 is fixed and the wire grip 15 is rotated. Can not be. Thereby, the bending angle of the bent portion 21 of the catheter shaft 20 can be maintained.

  By operating the operation arms 15a and 15b as described above, the bent portion 21 of the catheter shaft 20 is appropriately bent, the distal end of the catheter shaft 20 is inserted into the heart, and an abnormal site in the inner wall of the heart is searched. When an abnormal site is found, a high-frequency current is applied to the inner wall surface of the heart via the electrode 27e while the tip electrode 27e is in contact with the inner wall surface of the heart, thereby cauterizing the inner wall of the heart. At the same time, the electrode 27e is vibrated. Thereby, the blood around the electrode 27e is agitated, and the temperature rise of the ablation site and the blood in the vicinity thereof is suppressed. In this manner, deep lesion tissue can be cauterized while appropriately controlling the temperature of the inner wall surface and the vicinity thereof.

  The vibration of the electrode 27e is performed by rotating the rotation transmission wire 36 using the rotation drive source 38. The rotational motion input to the end of the rotation transmission wire 36 is transmitted to the above-described vibration generating mechanism 30 via the rotation transmission wire 36, and the swing head 33 swings. Thereby, the electrode 27e provided on the rocking head 33 vibrates in the Z-axis direction (the direction of the arrow 22 in FIG. 1). The cooling effect by vibrating the electrode 27e can be adjusted by changing the frequency of the electrode 27e, that is, the number of rotations of the rotation transmission wire 36.

  As described above, the catheter 1 according to the first embodiment includes the vibration generating mechanism 30 that converts the rotational motion into vibration (oscillation motion) in the vicinity of the distal end of the catheter shaft 20. The rotational drive source 38 for driving the vibration generating mechanism 30 is disposed outside the catheter shaft 20, and the rotational motion generated by the rotational drive source 38 is transmitted through the rotation transmission wire 36 inserted into the catheter shaft 20. 30. Therefore, the electrode 27e at the tip can be vibrated without increasing the outer diameter of the catheter shaft 20.

  The cooling effect due to the vibration of the electrode 27e varies depending on the frequency and amplitude of the electrode 27e. The frequency of the electrode 27 e depends on the rotation speed of the rotation transmission wire 36. In order to increase the frequency of the electrode 27e, it is necessary to rotate the rotation transmission wire 36 at a high speed. On the other hand, the amplitude of the electrode 27e can be changed, for example, by adjusting the eccentric amount of the crank pin 31c with respect to the input shaft 31a of the rotary shaft 31, the distance from the crank pin 31c to the electrode 27e, and the like. In order to increase the frequency and amplitude of the electrode 27e, a drive source that generates large power is required. In the first embodiment, since the rotational drive source 38 is disposed outside the catheter shaft 20 and the handle 10, there are few restrictions on the dimensions of the rotational drive source 38. Therefore, it is easy to use the rotational drive source 38 having a high rotational speed and high output. As a result, the catheter 1 having a high cooling effect can be realized without increasing the diameter of the catheter shaft 20. In addition, the rotational drive source 38 being arranged outside the handle 10 is advantageous in improving the operability of the catheter 1 and reducing the burden on the operator because the handle 10 is reduced in size and weight. .

  The vibration generating mechanism 30 for vibrating the electrode 27e and the rotation transmission wire 36 are mechanically independent from the bending mechanism 40 for bending the catheter shaft 20. Therefore, by providing the function of vibrating the electrode 27e, the basic characteristic required for the catheter, that is, bending the catheter shaft 20 so that the electrode 27e faces the desired direction, is not impaired. Further, the vibration generating mechanism 30 can be disposed on the electrode 27e side of the bending mechanism 40 along the longitudinal direction of the catheter shaft 20, which is to avoid an increase in the diameter of the catheter shaft 20. It is advantageous.

  As the catheter shaft 20 is bent, the rotation transmission wire 36 housed therein is also bent. Since the rotation transmission wire 36 is accommodated in the protective tube 37, the rotation transmission wire 36 contacts other members (for example, the cover 25, the guide tube 43, etc.) regardless of the curvature of the catheter shaft 20. Avoided. Therefore, the rotational power loss of the rotation transmission wire 36 is reduced, and a stable cooling effect is always obtained regardless of the curved state of the catheter shaft 20.

  The inventors have already prototyped a catheter 1 having a catheter shaft 20 having an electrode device 27 and a cover 25 with an outer diameter of φ2.4 mm, in which the tip electrode 27e vibrates at an amplitude of ± 0.5 mm and a vibration frequency of 60 Hz. ing.

  The rotation transmission wire 36 is accommodated in the small-diameter cover 25 together with the guide tube 43 accommodating the bending wires 42a and 42b and the electric wiring. Therefore, it is desirable that the rotation transmission wire 36 has the smallest possible diameter. Furthermore, since the rotation transmission wire 36 needs to transmit a rotational motion over a relatively long distance that is almost equal to or longer than the entire length of the catheter shaft 20, rotation followability (when one end is rotated, the other end is rotated by one end). It is desirable to have excellent torque transmission characteristics and characteristics that immediately rotate as much as possible. Furthermore, the rotation transmission wire 36 is also desired to have a high rust prevention characteristic and a flexibility that can be freely bent. Although there is no restriction | limiting in particular as the rotation transmission wire 36 which satisfies such a request, For example, the DMC spin rope whose outer diameter is about (phi) 0.30mm-(phi) 0.90mm can be used.

  In the first embodiment, the main surface of the leaf spring 41 constituting the bending mechanism 40 and the main surface of the hinge spring 34 constituting the vibration generating mechanism 30 are orthogonal to each other (FIGS. 2 and 3). Therefore, as shown in FIG. 1, the bending directions 21a and 21b of the catheter shaft 20 by the bending mechanism 40 and the vibration direction 22 of the electrode 27e by the vibration generating mechanism 30 are orthogonal to each other. In this configuration, as shown in FIG. 7, when the catheter shaft 20 is bent and the electrode 27e is pressed against the ablation surface (not shown), the catheter shaft 20 is swept along the longitudinal direction D1. The direction 22 in which the electrode 27e vibrates is substantially orthogonal to the sweep direction D1 of the electrode 27e when viewed along the normal direction of the surface to be ablated. Thereby, it is possible to cauterize a stripe-shaped region having a width corresponding to the amplitude of the electrode 27e only by moving the electrode 27e along the direction D1. This is advantageous for improving the ablation efficiency and avoiding local abnormal heating. In addition, since the possibility that the electrode 27e repeats contact and separation with respect to the surface to be ablated is reduced by vibrating the electrode 27e, more stable cauterization can be performed. Moreover, since the stirring effect of the blood around the electrode 27e when the electrode 27e is vibrated increases, a higher cooling effect can be obtained.

(Embodiment 2)
The second embodiment is different from the first embodiment regarding the configuration of the vibration generating mechanism built in the catheter shaft 20. Hereinafter, the catheter of the second embodiment will be described focusing on differences from the first embodiment.

  FIG. 8 is an exploded perspective view conceptually showing the vibration generating mechanism 230 of the second embodiment. The vibration generating mechanism 230 according to the second embodiment includes a rotation shaft 231, a base 232, a swing head 233, a hinge spring 234, and a connecting member 235.

  Similar to the rotation shaft 31 of the first embodiment, the rotation shaft 231 includes an input shaft 231a, a shaft base 231b, and a crank pin 231c in this order from the handle 10 side (lower side in FIG. 8). The input shaft 231a and the shaft base 231b are connected coaxially, and the crank pin 231c is eccentrically connected to these and connected to the shaft base 231b.

  As in the first embodiment, a base 232 and a swing head 233 each having a substantially cylindrical shape are connected via a hinge spring 234. The hinge spring 234 can be elastically bent and deformed in a bending plane parallel to the YZ plane. An input shaft 231a is inserted into a bearing hole 232a that penetrates the base 232, and the rotary shaft 231 is rotatably supported by the bearing hole 232a. The tip of the input shaft 231a that protrudes from the base 233 through the bearing hole 232a is connected to a rotation transmission wire 36 (not shown) as in the first embodiment.

  A connecting pin 233 a protrudes from the surface of the swing head 233 facing the base 232. In the connecting member 235, two through holes 235a and 235b having different positions on the XZ plane are formed. A crank pin 231c is inserted into the first through hole 235a, and a connecting pin 233a is inserted into the second through hole 235b.

  When the rotation shaft 231 rotates in one direction via the rotation transmission wire 36, the crank pin 231c is displaced along a circular orbit centering on the rotation center axis of the rotation shaft 231. The connecting member 235 transmits the displacement in the direction parallel to the bent surface of the hinge spring 234 (Z-axis direction) out of the displacement along the circular orbit of the crank pin 231c to the connecting pin 233a. As a result, the swing head 233 swings in the Z-axis direction. When the oscillating head 233 oscillates, the hinge spring 234 repeats elastic deformation in the bending surface. As described above, the vibration generating mechanism 230 of the second embodiment has a so-called crank mechanism, and the rotational motion input from the rotation transmission wire 36 to the input shaft 231a of the rotational shaft 231 is converted into the swing motion of the swing head 233. Convert to By continuously rotating the rotation transmission wire 36 at a constant rotational speed, an electrode device 27 (not shown) mounted on the rocking head 233 vibrates at a constant cycle.

  Similarly to the through holes 32b and 33b (see FIG. 4) of the first embodiment, the wiring connected to the electrode device 27 is inserted into the through hole 232b of the base 232 and the through hole 233b of the swing head 233.

  The catheter of the second embodiment is configured using the vibration generation mechanism 230 described above instead of the vibration generation mechanism 30 of the catheter 1 of the first embodiment. Also in the catheter of the second embodiment, a vibration generating mechanism 230 that converts rotational motion into vibration (oscillation motion) is built in the vicinity of the distal end of the catheter shaft 20. Therefore, as in the first embodiment, the electrode 27e at the tip can be vibrated without increasing the outer diameter of the catheter shaft 20.

  The second embodiment is the same as the first embodiment except for the above, and has the same effects as the first embodiment.

(Embodiment 3)
The third embodiment is different from the first embodiment regarding the configuration of the vibration generating mechanism built in the catheter shaft 20. Hereinafter, the catheter of the third embodiment will be described focusing on differences from the first embodiment.

  FIG. 9 is an exploded perspective view conceptually showing the vibration generating mechanism 330 of the third embodiment. The vibration generating mechanism 330 according to the third embodiment includes a rotation shaft 331, a base 332, a swing head 333, a slide cam 334, a connection screw 335, a compression coil spring 336, a first swing pin 337a, and a second swing pin 337b. .

  The rotating shaft 331 includes an input shaft 331a and a shaft base 331b in this order from the handle 10 side (lower side in FIG. 9). The input shaft 331a and the shaft base 331b are connected coaxially.

  A slide cam 334 is arranged coaxially with the rotation shaft 331 and facing the rotation shaft 331 in the axial direction. Helical cam surfaces are respectively formed on end surfaces of the shaft base portion 331b and the slide cam 334 facing each other. The spiral cam surface has a continuous inclined surface that gradually rises over a rotation range of 360 degrees with respect to the central axis, and the top (end) of the inclined surface is the bottom of the inclined surface through a step (drop). Adjacent to (starting edge).

  A compression coil spring 336 and a connecting screw 335 are inserted in this order into a through hole 334a that penetrates the slide cam 334 in the axial direction from the side opposite to the rotary shaft 331. The connection screw 335 passes through the compression coil spring 336 and the slide cam 334 in order, and is screwed to the rotary shaft 331. As a result, the compression coil spring 336 biases the slide cam 334 toward the rotating shaft 331.

  An input shaft 331a is inserted into a bearing hole 332a penetrating the base 332, and the rotating shaft 331 is rotatably supported by the bearing hole 332a. The tip of the input shaft 331a that protrudes from the base 332 through the bearing hole 332a is connected to a rotation transmission wire 36 (not shown) as in the first embodiment.

  The base 332 and the swing head 333 each having a substantially cylindrical outer peripheral surface are connected via a first swing pin 337a. The swing head 333 can swing with respect to the base 332 about the first swing pin 337a.

  The slide cam 334 is connected to the swing head 333 via the second swing pin 337b. The swing head 333 can swing with respect to the slide cam 334 around the second swing pin 337b. The second swing pin 337b is parallel to the first swing pin 337a.

  The rotation shaft 331 rotates in the arrow R direction via the rotation transmission wire 36. On the other hand, the slide cam 334 cannot be rotated because it is connected to the swing head 333 via the second swing pin 337b. Therefore, the spiral cam surface formed on the slide cam 334 slides on the spiral cam surface formed on the shaft base 331b of the rotary shaft 331. As the rotary shaft 331 rotates, the slide cam 334 moves away from the rotary shaft 331. When the top of the spiral cam surface of the slide cam 334 exceeds the top of the spiral cam surface of the shaft base 331b. The slide cam 334 is displaced toward the rotating shaft 331 by the biasing force of the compression coil spring 336. When the rotation shaft 331 rotates continuously, the slide cam 334 reciprocates along the rotation axis direction of the rotation shaft 331. By this reciprocation of the slide cam 334, the swing head 333 connected to the slide cam 334 swings with respect to the base 332 about the first swing pin 337a.

  As described above, the vibration generating mechanism 330 according to the third embodiment converts the rotational motion input from the rotation transmission wire 36 to the input shaft 331a of the rotary shaft 331 into the swing motion of the swing head 333. By continuously rotating the rotation transmission wire 36 at a constant rotational speed, an electrode device 27 (not shown) mounted on the rocking head 333 vibrates at a constant cycle.

  Similarly to the through holes 32b and 33b (see FIG. 4) of the first embodiment, the wiring connected to the electrode device 27 is inserted into the through hole 332b of the base 332 and the through hole 333b of the swing head 333.

  The catheter of the third embodiment is configured by using the vibration generation mechanism 330 described above instead of the vibration generation mechanism 30 of the catheter 1 of the first embodiment. Also in the catheter of the third embodiment, a vibration generating mechanism 330 that converts rotational motion into vibration (oscillation motion) is built in the vicinity of the distal end of the catheter shaft 20. Therefore, as in the first embodiment, the electrode 27e at the tip can be vibrated without increasing the outer diameter of the catheter shaft 20.

  The third embodiment is the same as the first embodiment except for the above, and has the same effects as the first embodiment.

  In FIG. 9, the spiral cam surfaces are formed on the mutually facing surfaces of the rotating shaft 331 and the slide cam 334, but the shape of the cam surface is not limited to this and can be arbitrarily set. For example, the cam surface may be a smooth curved surface whose position in the Y-axis direction changes in a sine wave shape along the circumference surrounding the central axis. It is not necessary that cam surfaces having the same shape are formed on both surfaces of the rotating shaft 331 and the slide cam 334 facing each other. One of the rotating shaft 331 and the slide cam 334 is formed with a cam surface having a predetermined shape on the surface facing the other, and the other is formed with a protrusion (cam) that slides on the one cam surface. It may be. In this case, the slide cam 334 may be omitted, and the protrusion (cam) may be formed directly on the swing head 333.

  The means for urging the slide cam 334 toward the rotating shaft 331 is not limited to the compression coil spring 336. For example, the base 332 and the swinging head 333 are connected using a plate spring similar to the hinge springs 34 and 234 shown in the first and second embodiments, and the slide cam 334 is connected to the rotary shaft using the elastic force of the plate spring. You may bias toward 331.

  The above first to third embodiments are merely examples. The present invention is not limited to these embodiments, and can be modified as appropriate.

  In the first to third embodiments, the direction 20 in which the electrode 27e vibrates by the vibration generating mechanisms 30, 230, 330 is perpendicular to the directions 21a, 21b in which the bent portion 21 of the catheter shaft 20 is bent by the bending mechanism 40. (See FIG. 1). However, the vibration direction 20 of the electrode 27e does not have to be perpendicular to the bending directions 21a and 21b of the catheter shaft 20, and may be parallel, for example, or may be inclined at any other angle. . Further, the vibration generating mechanisms 30, 230, 330 are rotated with respect to the bending mechanism 40 so that the operator can arbitrarily set the vibration direction 20 of the electrode 27e with respect to the bending directions 21a, 21b of the catheter shaft 20. There may be a mechanism that can do this. In the present invention, since the vibration generating mechanisms 30, 230, 330 and the bending mechanism 40 are independent from each other, the vibration direction 20 of the electrode 27e with respect to the bending directions 21a, 21b of the catheter shaft 20 can be arbitrarily set. it can.

  The configuration of the vibration generating mechanism is not limited to the above first to third embodiments. Any mechanism that can convert the rotational motion of the rotation transmission wire 36 into oscillation (vibration) can be employed. However, since the vibration generating mechanism 30 using the Scotch yoke mechanism shown in the first embodiment has a small number of parts and a simple structure, it is excellent in reliability and durability.

  In the first to third embodiments, the handle 10 is provided with the first connector 19a for transmitting rotational motion and the second connector 19b for electrical connection. Transmission of rotational motion and electrical connection may be performed. The common connector is detachably connected to a single cable for transmitting rotational power and transmitting / receiving electrical signals. According to this configuration, the number of cables connected to the handle 10 can be reduced.

  The rotational drive source 38 may be accommodated in the handle 10. According to this configuration, the first connector 19a and the rotation transmission cable 14 (see FIG. 1) for transmitting rotational power are not necessary.

  The configuration of the bending mechanism for bending the catheter shaft 20 is not limited to the first to third embodiments. For example, one of the two wires 42a and 42b (wire 42b) can be omitted. In this case, when tension is applied to the wire 42a, the wire 42a is pulled out from the catheter shaft 20, the bent portion 21 bends in the direction of the arrow 21a (see FIG. 1), and when the tension is released, the wire 42a The bent portion 21 returns to the initial state by being pulled into the catheter shaft 20 by the elastic recovery force. In addition, a bending mechanism known as a catheter can be applied to the catheter of the present invention.

  The present invention can be widely used as an ablation catheter for cauterizing living tissue. Especially, it can utilize preferably in order to cauterize the heart wall and treat an arrhythmia. However, it can also be used to cauterize parts other than the heart wall (for example, the sympathetic nerve of the renal artery).

1 Ablation catheter 10 Handle 20 Catheter shaft 27 Electrode device 27e Electrodes 30, 230, 330 Vibration generating mechanism 31 Rotating shaft 31c Crank pin 32 Base 33 Swing head 33a Groove 34 Hinge spring 36 Rotation transmission wire 37 Rotation transmission wire protective tube 38 Rotation Drive source 40 Bending mechanism 41 Leaf springs 42a, 42b Bending wire

Claims (7)

A catheter shaft having an electrode for ablating living tissue at its tip;
A vibration generating mechanism mounted with an electrode device including the electrode and housed in the catheter shaft;
A rotation transmission wire that is rotatably accommodated in the catheter shaft, one end of which is connected to the vibration generating mechanism, and the other end is led out from the end of the catheter shaft;
The rotation transmission wire transmits the rotational motion input to the other end thereof to the vibration generating mechanism,
The vibration generating mechanism is swung by the rotational movement of the rotation transmission wire,
The ablation catheter characterized in that the electrode vibrates by swinging of the vibration generating mechanism. A bending mechanism including at least one bending wire housed in the catheter shaft;
2. The bending mechanism according to claim 1, wherein when the at least one bending wire led out from the distal end of the catheter shaft is pulled, the bending mechanism bends and deforms the catheter shaft so that the electrode faces a desired direction. Ablation catheter.   The ablation catheter according to claim 2, wherein a direction in which the electrode vibrates is substantially perpendicular to a direction in which the catheter shaft is bent and deformed by the bending mechanism.   The ablation catheter according to claim 2 or 3, wherein the vibration generating mechanism is disposed on the electrode side with respect to the bending mechanism. The vibration generating mechanism is
An elastically bendable hinge spring;
A swing head held by the hinge spring;
A crankpin that is displaced along a circular orbit by the rotational movement of the rotation transmission wire;
The swing head is formed with a groove extending along a direction perpendicular to the bending surface of the hinge spring.
The ablation catheter according to claim 1, wherein the crank pin is engaged with the groove of the swing head. A handle for holding the distal end of the catheter shaft; and a rotational drive source for outputting a rotational motion for rotating the rotation transmission wire,
The ablation catheter according to claim 1, wherein the rotational drive source is disposed outside the handle. The rotation transmission wire is rotatably accommodated in a protective tube,
The ablation catheter according to claim 1, wherein the rotation transmission wire accommodated in the protective tube is accommodated in the catheter shaft.

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