CN215384578U

CN215384578U - Ablation catheter

Info

Publication number: CN215384578U
Application number: CN202121579684.7U
Authority: CN
Inventors: 冯君; 磨志岱; 李龙; 冯琬婷
Original assignee: Xinhang Medical Technology Guangzhou Co ltd
Current assignee: Xinhang Medical Technology Guangzhou Co ltd
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2022-01-04
Anticipated expiration: 2031-07-12

Abstract

The utility model discloses an ablation catheter, comprising: a first catheter having a first lumen therein; the second catheter is arranged in the first lumen and can move along the first lumen, and the distal end of the second catheter extends out of the distal end of the first catheter; the ablation assembly comprises a plurality of splines, the proximal ends of the splines are connected to the distal end of the first catheter, the distal ends of the splines are connected to the distal end of the second catheter, and at least one electrode is arranged on the splines; at least one part of the electrode protrudes out of the surface of the spline, and the height of the electrode protruding out of the surface of the spline is 0.1mm to 1 mm. According to the ablation catheter, the electrode is arranged to protrude out of the surface of the spline, so that the range of a pulse electric field emitted by the electrode of the ablation assembly is larger at one side far away from the longitudinal axis of the first catheter, the depth of a lesion is deep enough during ablation, and the ablation effect is better.

Description

Ablation catheter

Technical Field

The present invention relates to an ablation catheter.

Background

Radio Frequency (RF) ablation is currently a common modality used clinically to treat arrhythmias such as atrial fibrillation. The radiofrequency ablation can reach all positions of the anatomical structures of the heart, is suitable for arrhythmia including atrial fibrillation, atrial flutter, atrial velocity, ventricular premature, ventricular velocity and the like originated from pulmonary veins or non-pulmonary veins, has the defects of longer ablation operation time, higher requirement on the operation level of catheters of operators, pain during ablation due to thermal injury and easy pulmonary vein stenosis after operation.

Irreversible electroporation (IRE) is a rapidly developing and FDA-approved treatment for solid tumors. IRE may be a promising approach for cardiac Ablation, especially in comparison to RF, where it can produce lesions without the consequences of thermal damage, i.e. the ability to preserve surrounding tissue structure, such voltage pulses are more commonly referred to in the art as Pulsed Field Ablation (PFA). Aiming at the pulsed electric field ablation, how to improve the ablation efficiency and achieve the purpose of quickly, safely and effectively treating diseases such as arrhythmia and the like is a difficult problem to be solved urgently in the technology.

SUMMERY OF THE UTILITY MODEL

According to an aspect of the present invention, there is provided an ablation catheter comprising:

a first catheter having a first lumen therein;

a second catheter disposed within and movable along the first lumen, a distal end of the second catheter extending beyond a distal end of the first catheter;

the ablation assembly comprises a plurality of splines, the proximal ends of the splines are connected to the distal end of the first catheter, the distal ends of the splines are connected to the distal end of the second catheter, and at least one electrode is arranged on the splines;

at least one part of the electrode protrudes out of the surface of the spline, and the height of the electrode protruding out of the surface of the spline is 0.1mm to 1 mm.

According to the ablation catheter, the electrode is arranged to protrude out of the surface of the spline, so that the range of a pulse electric field emitted by the electrode of the ablation assembly is larger at one side far away from the longitudinal axis of the first catheter, the depth of a lesion is deep enough during ablation, and the ablation effect is better.

Further, the electrode is disposed on a surface of the spline on a side away from a longitudinal axis of the first conduit; the electrode covers 1/3-1/2 of the lateral surface of the spline.

This can avoid the discharge to the air (discharge to other direction than the tissue) and reduce the generation of bubbles. The current flowing through the area is smaller, and the stimulation of the pulse electric field to the nerve and skeletal muscle of the patient can be reduced.

Further, the ablation assembly has a first state and a second state, the ablation assembly being switchable between the first state and the second state, in the first state the plurality of splines converging proximate to the longitudinal axis of the first catheter; in a second state, at least a portion of the plurality of splines extends away from a longitudinal axis of the first conduit.

Thus, the collapsed ablation assembly in the first state facilitates movement of the entire catheter within the vasculature, and the second state expands to cover the vena cava to effect ablation.

Further, in the first state, the plurality of splines are substantially parallel to the longitudinal axis of the first catheter, and the distal end of the second catheter is at a position furthest relative to the distal end of the first catheter.

Further, during switching of the ablation assembly from the first state to the second state, the distal end of the second catheter is moved in a direction proximal to the distal end of the first catheter, and at least a portion of the plurality of splines are curved in a direction away from the longitudinal axis of the first catheter.

Therefore, the state switching of the ablation assembly is realized through the movement of the second catheter, and the switching is simple and convenient.

Further, the number of the electrodes arranged on each spline is three, and the electrodes are respectively a first electrode, a second electrode and a third electrode which are sequentially arranged from the far end to the near end of the spline.

Further, when the first electrode on the same spline is configured to a first polarity, the second and third electrodes are configured to a second polarity opposite the first polarity; or

When the first and third electrodes on the same spline are configured in a first polarity, the second electrode is configured in a second polarity opposite the first polarity; or

When the third electrode on the same spline is configured to a first polarity, the first and second electrodes are configured to a second polarity opposite the first polarity.

Therefore, by arranging the three electrodes in different polarities, the position of the ablation assembly with the strongest electric field strength in the longitudinal direction can be changed to adapt to the ablation requirements of different tissues or different diseases.

Further, the polarity of the second electrodes on two adjacent splines is opposite, and/or the polarity of the third electrodes on two adjacent splines is opposite.

Thus, a lateral electric field can be generated, and the ring-shaped and continuous ablation can be performed on the vena cava opening portion simply and quickly.

Further, the length of the electrode in the longitudinal direction is 0.5mm to 5 mm; the width of the electrode in the transverse direction is 1mm to 2 mm; the interval between two adjacent electrodes on the same spline is 2mm to 5 mm.

Further, the medical device also comprises a guide wire which is arranged in the lumen of the second catheter and can move relative to the second catheter to extend out of the far end of the second catheter.

Therefore, the catheter can be guided and supported during the use process of the ablation catheter, and the catheter can be attached more stably.

Drawings

Fig. 1(a) is a schematic overall structure of an ablation assembly of an ablation catheter in a first state, and fig. 1(b) is a schematic overall structure of the ablation assembly of the ablation catheter in a second state, according to some embodiments of the present invention;

fig. 2 is a partial structural schematic view of an ablation assembly of an ablation catheter of some embodiments of the utility model in a first state;

fig. 3 is a partial structural view of an ablation assembly of an ablation catheter of some embodiments of the utility model in a second state;

fig. 4 is a schematic structural view of an ablation assembly according to some embodiments of the utility model in a first state;

fig. 5 is a schematic structural view of an ablation assembly according to some embodiments of the utility model in a second state;

FIG. 6 is a schematic longitudinal cross-sectional view of a spline according to some embodiments of the present invention;

fig. 7 is a schematic transverse cross-sectional view of an ablation assembly according to some embodiments of the utility model;

FIG. 8(a) is a diagram showing the simulation effect of the electric field of the prior art in which the electrode is completely embedded in the spline, and FIG. 8(b) is a diagram showing the simulation effect of the electric field of the present invention in which at least a portion of the electrode protrudes from the surface of the spline;

FIG. 9 is a schematic diagram of an electrode polarity arrangement discharge according to the present invention;

FIG. 10 is a schematic diagram of an alternative electrode polarity arrangement of the present invention;

fig. 11 is a partial schematic view of an ablation assembly of an ablation catheter with a guidewire of the present invention in a second state.

Fig. 12 is a simulation diagram of electric field distribution of an electrode of an ablation catheter in accordance with some embodiments of the present invention, in which fig. 12(a) is a simulation diagram of electric field distribution of 1/4 ring electrode, fig. 12(b) is a simulation diagram of electric field distribution of 1/2 ring electrode, and fig. 12(c) is a simulation diagram of electric field distribution of ring electrode.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Fig. 1 schematically shows an ablation catheter 100 according to an embodiment of the present invention, the ablation catheter 100 is used in a tissue ablation device, the ablation device performs tissue ablation by applying a voltage pulse waveform to achieve irreversible electrical breakdown, the ablation device comprises a pulse signal generating device (not shown in the figure) for generating and transmitting a voltage pulse waveform to a control handle 200, the control handle 200 is respectively connected with the pulse signal generating device and the ablation catheter 100, the control handle 200 can control the ablation assembly 130 to switch between a first state and a second state, the ablation assembly 130 of the ablation catheter 100 releases the voltage pulse electric field to the tissue to generate pores in the cell membrane to destroy the cell membrane, the applied pulse electric field at the membrane is larger than the irreversible electroporation threshold of the cell to ensure that the pores are not closed, such electroporation is irreversible, resulting in cell necrosis or apoptosis, for therapeutic purposes. Common rapid heart rate disorders comprise focal tachycardia, reentry tachycardia, atrial fibrillation and the like, and the surgical treatment methods respectively comprise spot ablation of local pathological myocardial cells, linear ablation of reentry ring blocking and annular ablation of pulmonary vein isolation. The ablation catheter 100 delivers a pulsed electric field to ablate tissue, so as to eliminate ectopic pacing points and block abnormal electrical conduction, thereby achieving the effect of treating arrhythmia.

As shown in fig. 1-3, the ablation catheter 100 in this embodiment includes a first catheter 110, a second catheter 120, and an ablation assembly 130.

1-3, a first catheter 110 having a proximal end and a distal end and having a first lumen therein, the end of the first catheter 110 connected to the control handle 200 being its proximal end and the end opposite along its longitudinal axis being its distal end; specifically, the first catheter 110 is an elongated flexible hollow tube that can be bent to navigate the tortuous path of the patient's vasculature, and the proximal end of the first catheter 110 is attached to the control handle 200, the direction of bending/curving of which is controlled by the control handle 200. The transverse cross-sectional shape of the first conduit 110 is preferably circular, and may be various geometric shapes such as an elliptical ring, a square ring, etc., as long as the first conduit 110 has a first lumen therethrough.

As shown in fig. 1 and 3, the second catheter 120 has a proximal end and a distal end, the second catheter 120 has a second lumen therein, the second catheter 120 is disposed in the first lumen inside the first catheter 110 and passes through the first catheter 110 substantially coaxially with the first catheter 110, the second catheter 120 is movable relative to the first catheter 110 along the first lumen, the proximal end of the second catheter 120 is connected to a control handle 200, which is controlled by the control handle 200 to move along the longitudinal axis of the first catheter 110 in a direction approaching or separating from the distal end of the first catheter 110, and the distal end of the second catheter 120 protrudes from the first lumen beyond the distal end of the first catheter 110, i.e., on the distal side, the distal end of the second catheter 120 protrudes from the distal end of the first catheter 110. Specifically, the second conduit 120 is an elongated flexible hollow tube capable of being bent, and the transverse cross-sectional shape of the second conduit 120 is preferably a circular ring shape, and may be various geometric shapes such as an elliptical ring, a square ring, and the like. In some other embodiments, the second catheter 120 may not have a second lumen inside, i.e., the second catheter 120 may also be a solid tube or wire body.

As shown in fig. 4 and 5, an ablation assembly 130 is disposed at the distal end of the first catheter 110, the ablation assembly 130 including a plurality of splines 131 and a plurality of electrodes 132, at least one electrode 132 being disposed on each spline 131. The electrodes 132 are used for mapping, diagnosis and/or ablation of tissue, such as the heart.

As shown in fig. 4 and 5, the plurality of splines 131 of the ablation assembly 130 are strip-shaped members, and the splines 131 are flexible and can be bent under the action of external force, the splines 131 are insulated, the proximal ends of the plurality of splines 131 are connected to the distal end of the first catheter 110, and the distal ends of the splines 131 are connected to the distal end of the second catheter 120; preferably, the proximal ends of the plurality of splines 131 are connected together and then connected to the distal end of the first catheter 110, and may be fixedly connected to the distal end of the first catheter 110 by means of clipping or adhering, etc., and the distal ends of the plurality of splines 131 are connected together and then connected to the distal end of the second catheter 120, and may be fixedly connected to the distal end of the second catheter 120 by means of clipping or adhering, etc. Specifically, the plurality of splines 131 of ablation assembly 130 may be formed by cutting a flexible sheet of material, the flexible sheet of material having a substantially rectangular shape, cutting the flexible sheet of material along its length (longitudinal axis) into multiple portions to form the plurality of splines 131, but cutting the flexible sheet of material without cutting its proximal and distal ends, i.e., the proximal and distal ends of the plurality of splines 131 are still integrally connected, and after cutting, curling the flexible sheet of material along its longitudinal axis into a substantially cylindrical shape and anchoring or adhesively securing the same. The proximal end of the curved and fixed ablation assembly 130 is fixedly connected to the distal end of the first catheter 110, the proximal end of the ablation assembly 130 may be sleeved outside the distal end of the first catheter 110, or inserted inside the distal end of the first catheter 110, and then fixed by means of clamping, adhering and the like; the distal end of the ablation assembly 130 is fixedly attached to the distal end of the second catheter 120 such that the plurality of splines 131 are disposed about the longitudinal axis of the first tube, the longitudinal axis of the splines 131 being substantially parallel to the longitudinal axis of the first tube, which is defined as a first state of the ablation assembly 130, in which the plurality of splines 131 are in a furled state adjacent to the longitudinal axis of the first catheter 110; the ablation assembly 130 also has a second state, wherein movement of the distal end of the ablation assembly 130 in the proximal direction causes the ablation assembly 130 to switch from the first state to the second state, wherein during movement of the distal end of the ablation assembly 130 in the proximal direction, at least a portion of the plurality of splines 131 is bent away from the longitudinal axis of the first catheter 110 such that the entire ablation assembly 130 is in an expanded state, wherein the portion of the plurality of splines 131 that is bent is a portion between the distal end and the proximal end thereof, and wherein the distal end and the proximal end of the splines 131 are fixed to the first catheter 110 and the second catheter 120, respectively, without bending deformation. The transverse cross-section of each spline 131 is square, preferably semi-elliptical, and may also be square, hemispherical, rectangular.

Alternatively, the proximal and distal ends of the plurality of splines 131 may be split, and the proximal and distal ends of each spline 131 are connected to the distal end of the first catheter 110 and the distal end of the second catheter 120, respectively.

Alternatively, the transverse cross-section of plurality of splines 131 may be circular or elliptical.

As shown in fig. 1-3, switching between the first state and the second state of the ablation assembly 130 is associated with movement of the second catheter 120, and in particular, the ablation assembly 130 is in the first state with the distal end of the second catheter 120 at a position furthest from the distal end of the first catheter 110. During the process of switching the ablation assembly 130 from the first state to the second state, the distal end of the second catheter 120 moves towards the direction close to the distal end of the first catheter 110, so as to drive the distal end of the ablation assembly 130 to move towards the direction close to the distal end of the first catheter 110, so that at least a portion of the plurality of splines 131 is bent away from the longitudinal axis of the first catheter 110, and an expanded shape is formed.

In the second state, the ablation assembly 130 may be shaped as a substantially spherical basket, an ellipsoidal basket, a petal-shaped basket, or the like, the specific shape thereof is also associated with the moving distance of the second guide tube 120, and during the course of the distal end of the second guide tube 120 gradually moving toward the direction close to the distal end of the first guide tube 110, the ablation assembly 130 is first deformed from the collapsed, generally circular tubular shape to a generally ellipsoidal shape, at which point, the plurality of splines 131 are gradually curved, and as the distal end of the second catheter tube 120 continues to move in a direction closer to the distal end of the first catheter tube 110, the ablation assembly 130 is deformed from a generally ellipsoidal shape to a generally spherical shape, wherein the curvature of the plurality of splines 131 increases, and further movement of the distal end of the second catheter 120 in a direction closer to the distal end of the first catheter 110 changes the ablation assembly 130 from a generally spherical shape to a generally petaloid shape, wherein the curvature of the plurality of splines 131 increases. The distance that the distal end of the second catheter 120 is moved is controlled by the operator via the control handle 200 to change the shape/size of the ablation assembly 130 to accommodate the calibers of different vessels in the vasculature.

The ablation assembly 130 is switched from the second state to the first state, and then the opposite movement is switched as described above, that is, the second catheter 120 drives the distal end of the ablation assembly 130 to move away from the distal end of the first catheter 110, when the distal end of the second catheter 120 moves to the farthest position relative to the distal end of the first catheter 110, the ablation assembly 130 is completely straightened, the splines 131 are substantially parallel to the longitudinal axis of the first catheter 110, and the ablation assembly 130 is folded.

As shown in fig. 1 and 3, further, the ablation catheter 100 may further include a distal cap 140, the distal cap 140 is configured to connect the distal ends of the plurality of splines 131 with the distal end of the second catheter 120, that is, the distal cap 140 is fixedly connected with the distal end of the second catheter 120, and the distal ends of the plurality of splines 131 are fixedly connected with the distal cap 140, so that the plurality of splines 131 can be moved by the second catheter 120; i.e., the distal end of the second catheter tube 120, moves in a direction toward or away from the distal end of the first catheter tube 110, the distal end cap 140 and the distal ends of the plurality of splines 131 move in unison.

As shown in fig. 4-7, a plurality of electrodes 132 of ablation assembly 130 are disposed on each spline 131, one or more electrodes 132 are disposed on each spline 131, and electrodes 132 are disposed on splines 131 in an exposed manner such that a portion of electrodes 132 are embedded in splines 131 and another portion of electrodes 132 protrude from the surface of splines 131. Each electrode 132 is connected to the ablation device by an electrical lead 134, at least a portion of electrical lead 134 is disposed within spline 131, the portion of electrical lead 134 within spline 131 is electrically connected to the portion of electrode 132 embedded in spline 131 to enable delivery of voltage pulses from the ablation device to electrode 132, and each electrode 132 is connected to the ablation device by a separate electrical lead 134 such that each electrode 132 can be independently addressed, the ablation device can independently set the polarity of each electrode 132 or control the discharge of each electrode 132.

As shown in fig. 6 and 7, preferably, the electrode 132 is only disposed on the surface of the spline 131 on the side far from the longitudinal axis of the first catheter 110 (i.e. on the outer surface), during the ablation, only one side of the outer surface contacts the tissue, only one side of the outer surface is needed to be ablated by electric discharge, blood contacts one side of the inner surface of the spline 131, electric discharge is conducted in the direction of the rest of the non-tissue-facing direction, energy is converted into joule heat or oxidation-reduction reaction is generated (bubbles are generated in blood), and excessive bubbles generated in blood can cause certain harm to human body, therefore, the electrode 132 of the present embodiment is only disposed on the surface of the spline 131 on the side far from the longitudinal axis of the first catheter 110, that is, on the transverse surface, the electrode 132 only covers 1/3 to 1/2 of the transverse surface of the spline 131, such as the spline 131 with a square transverse cross section, the electrode 132 can cover the whole transverse outer surface of the spline 131 (occupying about 1/2 of the transverse surface), or covers a portion of the outer transverse surface of spline 131 (occupying transverse surface approximately 1/3); like the splines 131 with a circular transverse cross section, the electrode 132 can cover the circumferential surface of the spline 131 facing outward, and like a half-ring design (occupying approximately 1/2 on the transverse surface), the electrode 132 can be arranged in a manner that can avoid blank discharge (discharge in other directions than towards the tissue), reduce the current of pulse ablation, reduce the generation of bubbles, and reduce the generation of bubbles while maintaining the same ablation effect.

Taking spline 131 with a circular transverse cross section as an example, electrodes 132 with different coverage areas are arranged on spline 131, discharge voltage and current experiments are performed, experiments are performed on ring electrodes (90 °), 1/2 ring electrodes (180 °), and ring electrodes (360 °) with coverage areas of 1/4, and the pulse parameters of the experiments are as follows: monophase pulse, amplitude 750V, pulse duration 20 mus, pulse number 8; the following experimental data were obtained:

from the experimental data in the above table, it can be seen that the lateral coverage area of electrode 132 is reduced, and the current is correspondingly reduced, the current of electrode 132 having 1/4 ring whose lateral area covers the outer circumferential surface of spline 131 is reduced by 43% compared to the ring electrode, and the current of electrode 132 having 1/2 ring whose lateral area covers the outer circumferential surface of spline 131 is reduced by 23% compared to the ring electrode.

The stimulation response (skeletal muscle contraction, twitch) of the patient during the treatment process can be caused by the overlarge current of the pulse electric field, and the stimulation response is caused by three reasons: involuntary spinal nerve reflex tics, motor neuron stimulation induced muscle contraction, and direct electrical stimulation induced muscle contraction; the negative consequences of twitching are primarily patient pain, which affects comfort, and electrode 132 displacement caused by patient twitching, which affects ablation effectiveness.

In addition, the lateral coverage area of the electrode 132 is not as small as possible, the lateral coverage area of the electrode 132 becomes small, the coverage width (ablation depth) of the pulsed electric field also becomes small, in the procedure of pulsed electric field ablation for atrial flutter treatment, the mitral isthmus needs to be transmurally ablated to achieve the treatment effect, according to Wittkampf, F.H.M., et al, Where the wheel to draw the miral isthmus line in the binder evolution of the actual fibrosis: european Heart Journal,2005(7): p.689-95 anatomical data given in the literature, the depth of the endocardial surface and the epicardial surface cuff of the mitral isthmus of the heart is 8.4 ± 2.7mm, calculated as 8mm in the present application, the cuff is located in the coronary vein, therefore, the coverage width (ablation depth) of the pulsed electric field needs to be larger than the depth of the inner membrane surface and the outer membrane surface muscle cuff of the mitral isthmus, and the therapeutic effect can be maintained only by completely damaging the muscle cuff in the coronary vein.

FIG. 12 is a simulation diagram of electric field distribution, and FIG. 12(a) is a simulation diagram of electric field distribution at 1/4 ring electrode (90 °) at an electric field strength of 300V/cm, and the maximum coverage width of the pulse electric field is about 7.17 mm. FIG. 12(b) is a simulation of the electric field distribution at 1/2 ring electrodes (180 deg.), with a maximum coverage width of the pulsed electric field of about 10.00 mm. Fig. 12(c) is a simulation diagram of the electric field distribution of the ring electrode (360 °), and the maximum width of the pulse electric field is about 15.00 mm.

It is clear from this that the coverage width of the 1/4 ring electrode (90 °) electric field is less than 8mm, which is not sufficient to transmurally ablate the mitral isthmus and does not achieve therapeutic effects. And the covering widths of the 1/2 ring electrode (180 degrees) and the ring electrode (360 degrees) electric fields are larger than 8mm, the ablation injury depth exceeds 8mm, the mitral isthmus adventitia facial muscle sleeve can be completely ablated, and the effect of treating the atrial flutter is achieved. However, as can be seen from the above table of voltage and current experimental data, the current of the ring electrode (360 °) is larger than that of the 1/2 ring electrode (180 °), and the excessive current causes the stimulation response of the patient, and the discharge in all directions causes excessive bubbles in the blood. 1/2 the current of ring electrode 132(180 degree semi-ring electrode) is less than ring electrode (360 degree), can reduce patient's stimulation response, improves patient's comfort level in the treatment process, avoids causing the stimulation response because the electric current is too big to lead to the electrode to shift, guarantees to melt the effect. Meanwhile, the electric field is focused on one side of the tissue to be ablated, so that the current distribution of a non-target area is reduced, and the generation of bubbles is reduced.

As shown in fig. 4-6, preferably, three electrodes 132 are disposed on each spline 131, respectively a first electrode 1321, a second electrode 1322, and a third electrode 1323 disposed in sequence from the distal end to the proximal end of the spline 131; three electrodes 132 are spaced apart from the front half of the spline 131 in the longitudinal direction near the distal end of the spline 131. during tissue ablation, the basket-shaped ablation assembly 130 is mainly in contact with or in contact with the tissue in the front half near the distal end of the spline 131, so that the electrodes 132 do not need to be disposed in the rear half, taking the spherical ablation assembly 130 in the second state as an example, the portion between the position where the transverse distance between two opposite splines 131 is the largest and the distal position of the spline 131 is the front half, the transverse distance between two opposite splines 131 of the ablation assembly 130 in the second state is at least 28mm, the third electrode 1323 is disposed near the position where the transverse distance is the largest, and the transverse distance between the second electrodes 1322 of two opposite splines 131 of the spherical ablation assembly 130 in the second state is about 20 mm.

Each electrode 132 is substantially rectangular in shape, and the length direction thereof is arranged along the longitudinal direction of the spline 131, and the length of each electrode 132 in the longitudinal direction is 0.5mm to 5mm, preferably 3 mm; the spacing between two adjacent electrodes 132 on the same spline 131 is 2mm to 5mm, preferably 3mm, and the spacing of the first electrode 1321 from the distal end of the spline 131 may be 5 mm; the width of the electrode 132 in the transverse direction is 1mm to 2mm, the transverse width of the electrode 132 is related to the number of the splines 131, the larger the number of the splines 131 is, the smaller the transverse width of the electrode 132 can be, for example, in the case that the number of the splines 131 is 6, the transverse width of each electrode 132 can be 1.48mm or 1.66mm, and in the case that the number of the splines 131 is 8, the transverse width of each electrode 132 can be 1.11mm or 1.24mm, so as to satisfy the coverage of the whole vena cava by the pulse electric field.

Alternatively, the shape of the electrode 132 may be an oval or an oval bar.

As shown in fig. 8, the height of each electrode 132 protruding from the surface of spline 131 is 0.1mm to 1mm, preferably 0.5mm, and the height of the portion of electrode 132 protruding from the surface of spline 131 may be greater than the height of the portion of electrode 132 embedded in spline 131, or the height of the portion of electrode 132 protruding from the surface of spline 131 may be less than the height of the portion of electrode 132 embedded in spline 131; compared with the prior art in which the electrode 132 is completely embedded in the spline 131, as shown in fig. 8(a), the design that at least a part of the electrode 132 protrudes out of the surface of the spline 131 can make the coverage of the electric field generated between the electrodes 132 on the side away from the longitudinal axis of the first catheter larger, as shown in fig. 8(b), so that the depth of the lesion during ablation is deep enough to ensure the ablation effect.

Further, as shown in fig. 9 and 10, the electrodes 132 on each spline 131 can be discharged to form a pulsed electric field along the longitudinal direction of the spline 131, and the polarity arrangement of the three electrodes 132 on each spline 131 includes, but is not limited to, the following ways:

when the first electrode 1321 on the same spline 131 is configured as a first polarity (e.g., anode), the second electrode 1322 and the third electrode 1323 are configured as a second polarity (e.g., cathode) opposite the first polarity; alternatively, the first polarity may be a cathode and the second polarity may be an anode;

alternatively, when the first electrode 1321 and the third electrode 1323 on the same spline 131 are configured as a first polarity (e.g., an anode), the second electrode 1322 is configured as a second polarity (e.g., a cathode) opposite the first polarity; alternatively, the first polarity may be a cathode and the second polarity may be an anode;

alternatively, when the third electrode 1323 on the same spline 131 is configured as a first polarity (e.g., an anode), the first electrode 1321 and the second electrode 1322 are configured as a second polarity (e.g., a cathode) opposite the first polarity; the first polarity may be a cathode and the second polarity may be an anode.

As shown in fig. 9, the polarities of the first electrode 1321, the second electrode 1322 and the third electrode 1323 can be set by the ablation device, and the above-mentioned different polarities can be changed to change the position of the strongest electric field intensity in the longitudinal direction, for example, in the case of pulse ablation for treating atrial fibrillation, the most important thing for treating atrial fibrillation is to isolate the pulmonary veins, it is common practice to perform ablation at the opening of the pulmonary veins, and the closest position to the opening of the pulmonary veins is the position of the second electrode 1322 in the spherical basket in the second state of the ablation assembly 130, so that in order to make the depth of the lesion deep enough for achieving the desired ablation effect, it is necessary to generate an electric field with enough intensity at the position of the second electrode 1322, and both the first electrode 1321 and the third electrode 1323 can be configured as a first polarity (anode), the second electrode can be configured as a second polarity (cathode) opposite to the first polarity, both the first electrode 1321 and the third electrode 1323 discharge the second electrode 1322 to achieve the electric field strength necessary for sufficient ablation.

In some other embodiments, as shown in fig. 10, if it is desired to ablate tissue at other locations, the ablation assembly 130 may be shaped in the second state to accommodate the size of the tissue, e.g., to ablate the inside of the vena cava, the aperture of the ablation assembly 130 may be adaptively decreased, e.g., an oval basket is used, the curvature of the curved spline 131 may also be adaptively adjusted to change the maximum aperture of the oval basket, and the polarities of the first electrode 1321, the second electrode 1322, and the third electrode 1323 may also be adaptively adjusted, e.g., when ablating the inside of the vena cava, the third electrode 1323 is closest to the inside of the vena cava, so that the electric field strength at the location of the third electrode 1323 needs to be maximized, the third electrode 1323 may be set to the first polarity (cathode), the first electrode 1321 and the second electrode 1322 may be set to the second polarity (anode), both the first electrode 1321 and the second electrode 1322 discharge the third electrode 1323 to achieve the electric field strength necessary for sufficient ablation.

As shown in fig. 7, further, the polarity of the second electrodes 1322 on two adjacent splines 131 is opposite, i.e., when the second electrode 1322 on one spline 131 is configured as a first polarity (anode or cathode), the second electrode 1322 on the spline 131 adjacent to that spline 131 is configured as a second polarity (cathode or anode) opposite to the first polarity, and the polarity of the third electrode 1323 on two adjacent splines 131 is opposite, i.e., when the third electrode 1323 on one spline 131 is configured as a first polarity (anode or cathode), the third electrode 1323 on the spline 131 adjacent to that spline 131 is configured as a second polarity (cathode or anode) opposite to the first polarity; the arrangement mode of the electrode 132 can realize transverse discharge, the second electrode 1322 and/or the third electrode 1323 of the spline 131 adjacent to each other in pairs form a transverse annular pulse electric field through transverse discharge, and the annular pulse electric field ablation energy distribution mode is arranged, so that annular and continuous ablation can be simply and quickly performed on the pulmonary vein opening part, and finally, the pulmonary vein is electrically isolated, and the effect of treating atrial fibrillation is achieved.

It should be noted that the first electrodes 1321 on two adjacent splines 131 do not discharge laterally, i.e. only two circles of lateral pulsed electric fields are formed at the positions of the second electrode 1322 and the third electrode 1323.

Preferably, the number of splines 131 of the ablation assembly 130 is set to 6, in the treatment of atrial fibrillation, the treatment effect is achieved by isolating abnormal potentials in the pulmonary veins, according to liuxu, atrial fibrillation catheter ablations, 2009, atrial fibrillation catheter ablations, data in books, the maximum diameter of the pulmonary vein opening is about 25mm, the average diameter of the pulmonary veins is about 15mm, the maximum opening circumference of the pulmonary veins is 25mm × 3.14-78.5 mm, and the simulation result of the electric field of the electrode 132 on a single spline 131 shows that the electric field with the strength of 300V/cm can cover an area with the strength of at least about 15mm, therefore, the electric field is required to completely cover the pulmonary vein opening, and the number of splines 131 is 78.5/15-5.23, that is, at least 6 splines 131 are required to completely cover the pulmonary vein opening by the ablation electric field.

Alternatively, the number of the splines 131 of the ablation assembly 130 is set to 8, and the electric field simulation result of the electrode 132 on the single spline 131 shows that the electric field with the strength of 800V/cm can cover an area with the strength of at least about 10mm, so that the electric field is to completely cover the pulmonary vein opening, and the number of the splines 131 is 78.5/10 or 7.85, that is, at least 8 splines 131 are needed to completely cover the pulmonary vein opening.

As shown in fig. 4 and 5, further, a marking electrode 133 is disposed in the ablation assembly 130, and the marking electrode 133 is used for indicating the bending direction of the ablation catheter 100; the ablation operation usually needs to operate the ablation catheter 100 under fluoroscopy (X-ray) to ensure the safety of a patient, the spline 131 on the ablation assembly 130 is generally made of a high molecular compound, does not absorb the X-ray, and cannot prompt an operator to bend the ablation catheter 100 under the observation of the X-ray, so a special marking electrode 133 needs to be arranged to guide the operator to bend, the operation difficulty is reduced, the marking electrode 133 is made of metal, the metal electrode 132 can absorb the X-ray, and the X-ray can be clearly displayed under the fluoroscopy.

Preferably, the marker electrode 133 is provided as one, applied to the ablation catheter 100 that is bent in one direction, and the marker electrode 133 is provided on the spline 131 on the same side as the bending direction, and on the rear half of the distal end of the spline 131 in the longitudinal direction away from the spline 131.

Alternatively, the marker electrodes 133 may be provided in two for the bidirectional curved ablation catheter 100, the two marker electrodes 133 are respectively located on the splines 131 on one side of the two bending directions, that is, the two marker electrodes 133 are located on the two oppositely-located splines 131, the two marker electrodes 133 are differently arranged to indicate different bending directions, and the two marker electrodes 133 are both located on the rear half of the splines 131 in the longitudinal direction away from the distal ends of the splines 131.

The length of the marker electrode 133 in the longitudinal direction may be set to 0.5mm to 5mm, preferably 3mm, and the interval between the marker electrode 133 and the third electrode 1323 may be set to 2mm to 5mm, preferably 4 mm.

As shown in fig. 11, further, the ablation catheter 100 further includes a guide wire 150, the guide wire 150 being disposed within the second lumen of the second catheter 120 and being movable relative to the second catheter 120 to extend beyond the distal end of the second catheter 120. In an initial state, the guide wire 150 can be hidden in the second lumen of the second catheter 120, during use, the distal end of the guide wire 150 can slide out of the distal end of the second catheter 120, the guide wire 150 can be easily manipulated and placed in a pulmonary vein, and then the ablation catheter 100 is conveyed along the guide wire 150, so that the ablation assembly 130 can be accurately conveyed to a corresponding pulmonary vein opening part to play a role in guiding the ablation catheter 100; in addition, the guide wire 150 can also play a role in supporting the ablation catheter 100, the ablation catheter 100 without the guide wire 150 in the prior art has poor stability even when reaching the pulmonary vein opening, the catheter displacement may be caused by the rhythmic contraction of the heart, and the ablation effect of the pulsed electric field can be affected, the guide wire 150 can be arranged to support the ablation catheter 100 placed at the pulmonary vein opening, so that the unexpected displacement (such as the displacement caused by the cardiac contraction) of the ablation catheter 100 is reduced, the ablation catheter 100 is more stably attached, and the effect is better when the ablation assembly 130 delivers the pulsed electric field.

Alternatively, the portion of the distal end of the guidewire 150 that extends beyond the distal end of the second catheter 120 may be crimped in a hook or loop configuration to allow the guidewire 150 to better stabilize the ablation assembly 130.

In the description of the present invention, unless explicitly stated or limited otherwise, the terms "first", "second", "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless specified or indicated otherwise; the terms "connected," "fixed," and the like are to be construed broadly and may, for example, be fixedly connected, detachably connected, integrally connected, or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description of the present invention, it should be understood that the terms of orientation such as "front", "back", "upper", "lower", "inner" and "outer" used in the embodiments of the present invention are described with respect to the angles shown in the drawings, and should not be construed as limiting the embodiments of the present invention. In addition, in this context, it will also be understood that when an element is referred to as being "directly connected to" or "directly behind" another element, it can also be indirectly connected to "directly" or "directly behind" the other element through intervening elements.

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the utility model.

Claims

1. An ablation catheter, comprising:

a first catheter having a first lumen therein;

2. The ablation catheter of claim 1, wherein the electrode is disposed on a surface of the spline on a side away from a longitudinal axis of the first catheter; and the electrode covers 1/3-1/2 of the lateral surface of the spline.

3. The ablation catheter of claim 1 or 2, wherein the ablation assembly has a first state and a second state, the ablation assembly being switchable between the first state and the second state, the plurality of splines converging proximate to a longitudinal axis of the first catheter in the first state; in a second state, at least a portion of the plurality of splines extends away from a longitudinal axis of the first conduit.

4. The ablation catheter of claim 3, wherein in a first state, the plurality of splines are substantially parallel to a longitudinal axis of the first catheter, and a distal end of the second catheter is located at a distal-most position relative to a distal end of the first catheter.

5. The ablation catheter of claim 4, wherein during switching of the ablation assembly from the first state to the second state, the distal end of the second catheter is moved in a direction proximal to the distal end of the first catheter, and at least a portion of the plurality of splines are curved in a direction away from the longitudinal axis of the first catheter.

6. The ablation catheter of claim 4 or 5, wherein the number of electrodes disposed on each spline is three, and the three electrodes are a first electrode, a second electrode and a third electrode which are sequentially disposed from the distal end to the proximal end of the spline.

7. The ablation catheter of claim 6, wherein when the first electrode on the same spline is configured in a first polarity, the second and third electrodes are configured in a second polarity opposite the first polarity; or

8. The ablation catheter of claim 7, wherein the polarity of the second electrodes on adjacent splines is reversed, and/or the polarity of the third electrodes on adjacent splines is reversed.

9. The ablation catheter of claim 8, wherein the electrode has a length in the longitudinal direction of 0.5mm to 5 mm; the width of the electrode in the transverse direction is 1mm to 2 mm; the interval between two adjacent electrodes on the same spline is 2mm to 5 mm.

10. The ablation catheter of claim 1, further comprising a guidewire disposed within the lumen of the second catheter and movable relative to the second catheter to extend beyond the distal end of the second catheter.