Ablation Catheters

Abstract

The ablation catheter has an annular distal end (1). The annular distal end (1) includes an arc-shaped distal tube (3). In the ablation catheter, a plurality of electrode pairs (2) are arranged at intervals along the arc-shaped extension direction of the distal tube (3). The plurality of electrode pairs (2) respectively surround the distal tube (3). Each electrode pair (2) includes two annular electrodes (11, 12), each of which is fully surrounded by the distal tube (3). The design of the electrode pairs is based on the premise of ensuring ablation efficacy and safety, and is more convenient for adjusting the diameter of the annular distal end (1), while the electrode pairs (2) can be used more accurately to collect electrophysiological signals, and avoids the electrode spacing being too large to affect the determination of electrical signal changes.

Description

[Technical field]

[0001] The present invention relates to the field of electrophysiological ablation, and more particularly to an ablation catheter having an annular distal tip with adjustable diameter. [Background technology]

[0002] Conventionally, there are two commonly used methods for treating arrhythmias such as atrial fibrillation in clinical practice: radiofrequency (RF) ablation and cryoablation. The success of ablation mainly depends on the quality and appropriateness of the damage caused during the surgical procedure. The damage must destroy the tissue causing the arrhythmia or sufficiently disrupt or isolate the abnormal electrical conduction in the myocardial tissue. However, excessive ablation may affect the surrounding healthy tissue and nerve tissue. The disadvantages of radiofrequency ablation are that the ablation procedure takes a relatively long time, the requirements for the catheter manipulation level of the surgeon are relatively high, the ablation is painful due to thermal damage, and the problem of pulmonary vein stenosis is likely to occur after the procedure. When radiofrequency energy is applied to the target tissue, it affects non-target tissue, and when radiofrequency energy is applied to the atrial wall tissue, it may cause damage to the esophagus or phrenic nerve. In addition, radiofrequency ablation has the risk of causing crust formation in the tissue, which may lead to thrombosis problems. In cryoablation, if the cryoballoon and the pulmonary vein are tightly attached, circular ablation isolation can be completed in one or several sessions, making the patient painless and shortening the operation time, but the damage rate to the phrenic nerve in cryoablation is relatively high.

[0003] Pulsed electric field technology can apply a short-term high voltage to tissue, generating a localized high electric field of several hundred volts per centimeter. The localized high electric field destroys cell membranes by creating holes in them (cell membranes are altered and "permeable"). Since different tissue cells have different thresholds for voltage penetration, pulsed electric field technology can selectively treat myocardial cells (which have a relatively low threshold) without affecting other non-targeted tissues (such as nerves, esophagus, blood vessels, blood cells, etc.). At the same time, due to the extremely short time of energy release, pulsed technology does not produce thermal effects, avoiding problems such as tissue crusting and pulmonary vein stenosis.

[0004] However, the voltage of the high-voltage pulse is relatively high, and it is necessary to avoid excessive concentration of energy between the electrodes, which can easily cause safety accidents, so it is necessary to strengthen the insulation of the electrodes and the insulation inside the catheter. Conventional ablation catheters that use high-voltage pulses for ablation are prone to ionization between the electrodes, and the ablation time with high-voltage pulses is short, and precise positioning is required.

[0005] Atrial fibrillation (AF) is a common sustained arrhythmia that seriously endangers human health and affects the quality of life. The reason why pulmonary veins are the most common local lesion in atrial fibrillation is due to the presence of the pulmonary vein myocardial sleeve. A colony of cardiomyocytes exists between the intima and adventitia of the pulmonary vein, and wraps around the pulmonary vein like a sleeve from the atrial side to the pulmonary side, and is called the myocardial sleeve. The cells that form the myocardial sleeve are of a different origin from the atrial muscle, and their electrophysiological properties are also different, resulting in the formation of an abnormal excitable substrate. The atrial muscle surrounding the pulmonary vein also contains arrhythmia substrates that trigger or maintain AF, just like the pulmonary vein, so the myocardial tissue surrounding the pulmonary vein may be ablated during ablation isolation.

[0006] The conventional method involves point-sequential point ablation of the pulmonary vein vestibule to form an annular isolation zone, which requires a long surgical time, places a great burden on patients and doctors, and often results in leakage points leading to recurrence. Therefore, there is an urgent need to design a catheter that can quickly ablate and isolate the pulmonary vein vestibule in one go.

[0007] Previously known ring electrode catheters have been of a fixed shape and size and do not provide for good targeting and steering to anatomy of differing lumen sizes.

[0008] Therefore, there is a need for an ablation catheter having an annular distal tip that has the ability to adjust the diameter, adapt to different tissue structures, provide good abutment, and form a closed annular ablation zone upon ablation discharge. Summary of the Invention

[0009] The present invention provides an ablation catheter with a ring-shaped distal end. On the one hand, the diameter of the ring-shaped distal end is adjustable to adapt to different tissue structures and achieve good abutment. On the other hand, an electrode pair is arranged on the ring-shaped distal end to adapt to deformation contraction by adjusting the diameter of the ring-shaped distal end. And the ring electrodes in the electrode pair work in pairs in ablation mode and work alone in measurement mode.

[0010] In a first aspect of the present invention, there is provided an ablation catheter having an annular distal end including an arcuate distal tube having a plurality of electrode pairs spaced apart along the arcuate extension of the distal tube, each of the plurality of electrode pairs surrounding the distal tube.

[0011] Preferably, the number of electrode pairs is 2N+1, where N is a positive integer.

[0012] In the ablation catheter according to the first embodiment of the present invention, each electrode pair includes two annular electrodes surrounding a distal tube, and each annular electrode has a width L in the arcuate extension direction of the distal tube. The spacing between the two annular electrodes in one electrode pair is d, the spacing between adjacent electrode pairs is D, and the diameter of each annular electrode is S, where S>D=(2×L+d)×k, where k is a correction factor and k is a value between 0.7 and 1.4.

[0013] Preferably, L has a value between 0.50 and 1.5 millimeters, d has a value between 1 and 3 millimeters, and D has a value between 3 and 6 millimeters.

[0014] Preferably, the ring electrode is a spiral electrode. The spiral electrode may be formed by winding an electrode lead wire, or the ring electrode may be cut to form an electrode in a spiral shape.

[0015] Preferably, the catheter is a pulsed electric field ablation catheter, which is used to deliver and deliver pulsed ablation energy to the intended ablation site.

[0016] Preferably, the catheter is used for ablation of the heart and surrounding tissue.

[0017] When used for pulsed electric field ablation, the polarity of the two electrodes in each electrode pair is the same, which is equivalent to applying a voltage to one electrode, and the polarity of adjacent electrode pairs is opposite.

[0018] When used for electrophysiological measurements, the two electrodes in each electrode pair are used independently to acquire electrophysiological signals.

[0019] Preferably, the amplitude of the voltage applied to each electrode pair is 1000 to 4000V.

[0020] In the ablation catheter according to the first aspect of the present invention, a positioning sensor is disposed below the electrode pair and is located inside the distal tube.

[0021] Preferably, the length of the distal tube of the positioning sensor in the arcuate extension direction is equal to the width of the distal tube of the electrode pair in the arcuate extension direction. Specifically, the length of the distal tube of the positioning sensor in the arcuate extension direction is equal to the sum of the widths of the two ring electrodes of the electrode pair in the arcuate extension direction of the distal tube and the distance between them.

[0022] Preferably, the position sensor includes a first position sensor and a second position sensor, the first position sensor being disposed beneath a first electrode pair from a tip of the annular distal tip, and the second position sensor being disposed beneath an electrode pair at an intermediate position of the annular distal tip.

[0023] In the ablation catheter according to the first aspect of the present invention, the annular diameter of the annular distal end is collapsible.

[0024] In its natural state, the annular distal tip may have a helical shape, with an annular diameter of 20-35 mm. The annular distal tip has a separation between its leading and trailing ends, the separation distance being 1 / 5-1 / 4 of the annular circumference.

[0025] When the annular distal tip is minimally contracted, the annular diameter is between 12 and 15 millimeters, the annular distal tip presents a closed annulus in annular cross section, and the electrode pairs at the distal and distal ends of the annular distal tip do not overlap.

[0026] In the ablation catheter according to the first aspect of the present invention, one end of the terminal tube is a free end and is located at the tip of the annular distal end. The free end has a damage prevention tip. The other end of the terminal tube is a fixed end. The catheter may further include: a terminal rigid tube, one end of which is connected to the fixed end of the terminal tube; a distal end tube, one end of which is connected to the other end of the terminal rigid tube; a proximal end tube, one end of which is connected to the other end of the distal end tube; a handle assembly, one end of which is connected to the other end of the proximal end tube; and a connector, which is connected to the other end of the handle assembly.

[0027] Preferably, the catheter further comprises: a support member disposed through the distal tubular body and the interior of the distal rigid tube and made of a memory alloy material; a shrink rope disposed within the annular interior of the support member, one end of which is secured to the injury prevention tip together with one end of the support member; and a shrink rope that, when contracted, pulls and deforms the support member to adjust the diameter of the annular distal tip.

[0028] Preferably, the catheter further includes a protective tube, which encases the exterior of the support member and the shrink rope.

[0029] Preferably, the handle assembly includes a knob arranged to rotate to control the retraction and recovery of the retraction rope.

[0030] Preferably, a positioning sensor is fixed to the outer periphery of the protective tube, the positioning sensor has a cylindrical structure, and the protective tube passes through the center of the cylindrical structure.

[0031] Preferably, the positioning sensor and the protective tube are fixed by a sheath tube.

[0032] Preferably, the ablation catheter according to the first aspect of the present invention further includes a push button, disposed between the handle assembly and the proximal tube, the push button being connected to one end of a traction assembly disposed in the distal tube, the other end of the traction assembly being connected to the terminal rigid tube, and the push button can be pressed to control the tightening or loosening of the traction assembly and realize the bending of the distal tube.

[0033] Preferably, the traction assembly is laterally disposed within the distal end tube.

[0034] In the ablation catheter according to the first aspect of the present invention, a positioning electrode can be provided on the distal rigid tube, and a third positioning sensor can be provided inside the distal rigid tube.

[0035] In the ablation catheter according to the first aspect of the present invention, the connectors include: a first connector arranged to connect to the positioning sensor by a first cable and transmit positioning information; and a second connector arranged to connect to the annular electrodes on each electrode pair by a second cable, respectively, and transmit ablation energy.

[0036] According to a second aspect of the present invention, there is provided a method for controlling the function of electrode pairs on an ablation catheter according to the first aspect of the present invention, the ablation catheter being a pulsed electric field ablation catheter for use in ablation of the heart and surrounding tissue, the method including: delivering electric field energy of the same polarity to two electrodes in each electrode pair in an ablation mode of the catheter, applying voltages to corresponding tissues as if the two electrodes in the electrode pair were one electrode, and delivering electric field energy of opposite polarity to adjacent electrode pairs to achieve a pulsed electric field ablation function; and collecting electrophysiological signals independently from the two electrodes in each electrode pair in a measurement mode of the catheter to achieve an electrophysiological measurement function.

[0037] According to a third aspect of the present invention, a computer readable medium is provided having stored thereon processor executable instructions which, when executed by the processor, cause the processor to perform the method of controlling function of an electrode pair of an ablation catheter of the second aspect of the present invention.

[0038] As mentioned above, the conventional fixed diameter annular pulse ablation catheter cannot achieve good abutment against the luminal structure. The diameter is too large and cannot enter the luminal structure. The diameter is too small and cannot achieve good abutment against the luminal structure, which affects the efficiency and effect of ablation. At the same time, the pulse electric field ablation needs to avoid the electric field being too concentrated to cause safety risks, so the single electrode area needs to be large (the length or width dimension of the electrode is as large as possible), and the diameter needs to be adjustable in the annular catheter structure. If the electrode area is large and the electrode length or width dimension is larger, the annular diameter adjustment is not applicable. Since the variable diameter needs to make a compressive change to the shape of the annular part, if the electrode dimension is too large, the length of the local rigid part of the annular catheter will increase, making it difficult to deform and shrink the annular catheter.

[0039] In order to ensure the safety of pulsed electric field ablation, the electrode spacing used in pulsed electric field ablation is generally designed to be relatively large. However, too large an electrode spacing is likely to introduce other interfering signals when collecting electrophysiological signals, making it difficult to collect local electrical signals accurately, which is likely to affect the operator's analytical judgment and affect the efficiency of surgery. Smaller electrodes and smaller electrode spacing are desirable for measuring electrophysiological signals, which can achieve accurate measurement.

[0040] Considering these points, the present invention proposes to adopt an electrode pair. In this way, when used as an ablation electrode, a pair of electrodes can function equivalently to one electrode. When used as a measurement electrode, the two electrodes in the electrode pair are used independently. Under the premise of ensuring ablation efficacy and safety, the design of the electrode pair is more convenient for adjusting the diameter of the annular distal end, and at the same time, the electrode pair is more accurate in collecting electrophysiological signals, and avoids the electrode spacing being too large to affect the judgment of changes in electrical signals.

[0041] The positioning sensor is useful for realizing the positioning and morphological display of the annular catheter. The annular part with adjustable diameter needs to undergo a large compressive deformation, so the rigidity of the conventional normal positioning sensor is relatively large and it is difficult to deform according to the deformation of the annular part. However, without the positioning sensor, the annular pulse catheter has a very high safety risk, and the overlapping of electrodes with different polarities will cause ignition problems, and the ignition will burn the heart tissue.

[0042] Therefore, in a preferred embodiment of the present invention, a positioning sensor installation method that can be freely deformed and does not affect the performance is proposed, and is applied to the loop portion of the catheter with adjustable diameter. [Brief description of the drawings]

[0043] The present invention may be more fully understood in conjunction with the following detailed description and the accompanying drawings, in which like elements are numbered in a similar manner, and in which: [Figure 1] 1 is an overall schematic diagram of an ablation catheter according to the present invention. [Diagram 2] FIG. 2 is a schematic diagram of the annular distal end in its natural state. [Diagram 3] FIG. 13 is a schematic diagram of the arrangement of electrode pairs in the natural state of the annular distal end. [Figure 4] FIG. 13 is a schematic diagram of the arrangement of the traction assembly of the distal end tube. [Diagram 5] FIG. 2 is a schematic diagram of the annular distal end in a contracted state. [Figure 6]FIG. 13 is a schematic diagram of the electrode pair arrangement in the contracted state of the annular distal end. [Figure 7] FIG. 2 is a schematic diagram of a support member. [Figure 8] FIG. 2 is an internal schematic view of the annular distal end. [Figure 9] FIG. 13 is a schematic diagram of the placement of positioning sensors at the annular distal end. [Figure 10] FIG. 13 is a schematic tensile side view of an annular distal end. [Figure 11] FIG. 2 is a schematic cross-sectional view of the tip of the annular distal end. [Figure 12] FIG. 2 is a cross-sectional schematic view of a distal end tube. [Figure 13] FIG. 2 is a schematic diagram in which the annular electrode is a spiral electrode. [Figure 14] FIG. 13 is a schematic diagram of the bending effect of the distal end tube. [Figure 15] FIG. 13 is an internal schematic view of the annular distal end contraction control assembly. [Figure 16] FIG. 13 is a diagram showing an application example of an embodiment of the present invention. [Figure 17] FIG. 13 is a diagram showing another application example of the embodiment of the present invention. [Figure 18] 3 is a schematic diagram of an electric field distribution when electric field energy is emitted by the ablation catheter of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The following uses embodiments to further describe the technical solutions of the present invention in detail in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0045] Ablation Catheters FIG. 1 is a schematic overall view of an ablation catheter according to the present invention. As shown in FIG. 1, the ablation catheter according to the present invention includes, in the overall structure, from the distal end to the proximal end, an annular distal tip 1, a terminal hard tube 4, a distal tube 5, a proximal tube 6, a handle assembly 15, a connector 18 and a connector 19. The annular distal tip 1 is disposed at the most distal end of the catheter. The terminal hard tube 4 is used to connect the annular distal tip 1 and the distal tube 5. The terminal hard tube 4 is preferentially selected from a polyetheretherketone polymer material having high material hardness. The distal tube 5 is disposed between the proximal tube 6 and the terminal hard tube 4. The distal tube 5 is bent under the operation of the handle assembly 15 and is used to make the annular distal tip 1 reach a desired site. The proximal tube 6 is used to connect the distal tube 5 and the handle assembly 15. The connector of the ablation catheter shown in FIG. 1 includes at least two types of connectors. That is, the connector 18 is used to transmit position information between the catheter and the device. Connector 19 is used to transmit ablation energy between the catheter and the device.

[0046] The ablation catheter shown in FIG. 1 also includes a push button 16 between the proximal end tube 6 and the handle assembly 15 , and a knob 17 on the handle assembly 15 .

[0047] In the terms of this disclosure, the "distal end" and "proximal end" are relative to the catheter operator, e.g., the distal end may be the end closer to the tissue to be ablated and the proximal end may be the end closer to the catheter operator. Additionally, "tip" and "end" generally refer to the free end and the fixed end (or "connected end").

[0048] Although the above-described elements and components are combined together to form one preferred embodiment of an ablation catheter according to the present invention, one skilled in the art should understand that an ablation catheter according to the present invention is not limited to including all of these elements and components.

[0049] A schematic diagram of the annular distal tip in its natural state is shown in FIG. 2. As shown in FIG. 2, the annular distal tip has an outer diameter of 20-35 mm in its natural state and has an appearance of the letter "C". The tip of the annular distal tip is a damage prevention tip 8, and the end is a hard end, with a certain distance between the tip and the end, which is 1 / 4-1 / 5 of the distance of the approximately circular structure. The annular distal tip has a spiral shape in its natural state, and a terminal tube 3 is provided on the annular distal tip, which has an arc shape according to the shape of the annular distal tip. The terminal tube 3 is preferentially supported by a highly elastic polyurethane material. A plurality of electrode pairs 2 are provided on the terminal tube 3. In a preferred embodiment of the present invention, the number of electrode pairs is 2N+1, where N is a positive integer. Each electrode pair is composed of two electrodes. For example, the first electrode pair closest to the tip (damage prevention tip 8) is composed of an annular electrode 11 and an annular electrode 12.

[0050] Briefly, the ablation catheter of the present invention has an annular distal tip 1. The annular distal tip 1 includes an arcuate distal tube 3. The innovation of the present invention is that a plurality of electrode pairs 2 are spaced apart along the arcuate extension of the distal tube. Each of the plurality of electrode pairs 2 surrounds the distal tube 3.

[0051] FIG. 2 also shows the distal rigid tube 4 and a positioning electrode 41 disposed thereon, which will be described below.

[0052] As can be seen from both Figures 1 and 2, one end of the distal tube 3 is a free end, which is located at the tip of the annular distal end 1. The free end has a damage prevention tip 8. The other end of the distal tube 3 is a fixed end. One end of the rigid distal tube 4 is connected to the fixed end of the distal tube 3. One end of the distal tube 5 is connected to the other end of the rigid distal tube 4. One end of the proximal tube 6 is connected to the other end of the distal tube 5. One end of the handle assembly 15 is connected to the other end of the proximal tube 6. A push button 16 may be provided between the handle assembly 15 and the proximal tube 6. A knob 17 may be provided on the handle assembly 15. A connector 18 and a connector 19 are connected to the other end of the handle assembly 15.

[0053] FIG. 3 is a schematic diagram of the arrangement of the electrode pair in the natural state of the annular distal end. As shown in FIG. 3, for example, the first electrode pair 111 is composed of two fine annular electrodes. The annular electrodes are preferably gold or platinum electrodes, and the dimension in the arcuate extension direction of the terminal tube (which can be called "length" or "width") is 0.50 to 1.5 mm. The clearance distance between the annular electrodes is 1 to 3 mm. The clearance distance between the annular electrode pair is 3 to 6 mm. It should be noted here that the original intention of the design of the width and spacing of the electrodes adopted here is that the diameter of the annular distal end can be contracted, so the dimensions of the electrodes must be adapted thereto, and in particular the dimensions of the electrodes in the arcuate extension direction of the terminal tube, so-called "length" or "width", must be appropriate, and if the dimensions are too large, they will affect the contraction effect of the annular distal end, so two annular electrodes are provided to form a set of electrode pairs.

[0054] Briefly, each electrode pair 2 includes two annular electrodes, e.g., annular electrode 11 and annular electrode 12, surrounding a distal tube 3, and the width of each annular electrode in the arcuate extension direction of the distal tube, the spacing between two annular electrodes in the same electrode pair, and the spacing between adjacent electrode pairs must be set to appropriate dimensions. In a preferred embodiment, there is a certain constraint between these dimensions and the diameter of each annular electrode (described in detail below).

[0055] Terms such as "end tube arcuate dimension," "spacing," and the like are used in this disclosure to refer to the annular or arcuate perimeter dimension of the annular distal end that contacts the myocardial tissue to be ablated, and not the thickness dimension of the end tube or annular distal end. Those skilled in the art will appreciate that such dimensions may be described as either "length" or "width," and that by default, either "length" or "width" refers to the annular perimeter dimension, and not the thickness dimension of the tube.

[0056] As described above, the annular distal end may be provided with 2N+1 (odd number) annular electrode pairs. As shown in FIG. 3, in discharge ablation, positive and negative voltages are applied alternately to the first to ninth electrode pairs 111-119, for example, positive polarity is applied to the first electrode pair 111 and negative polarity is applied to the second electrode pair 112 in sequence, that is, the polarity of adjacent electrode pairs is reversed. The last electrode pair in FIG. 3 is the ninth electrode pair 119, whose polarity is positive. Since the number of electrode pairs is an odd number, the polarity of the last electrode pair and the first electrode pair are the same. For example, the polarity of the first electrode pair 111 and the ninth electrode pair 119 are both positive. The purpose of such an arrangement is to ensure that no arc problem occurs even if the electrodes overlap when the annular distal end contracts, and to ensure safety of use. In the ablation mode, the two electrodes in the electrode pair have the same polarity during discharge ablation, and can be considered equivalent to one electrode. The split electrode pair design (consisting of two annular electrodes) can reduce the stiffness of the distal tube and facilitates the reduction of the annular distal tip dimensions.

[0057] The ring electrode may be a helical electrode, as shown in Figure 13. A helical electrode is an electrode lead wire wound or a ring electrode cut into a helical form.

[0058] Returning to FIG. 3, when the annular electrodes are disposed in the terminal tube 3, the rigidity of the terminal tube can be reduced, and the diameter of the annular distal end can be easily reduced. The electrode pairs 111-119 are all in an annular, preferably equally spaced fashion, surrounding the terminal tube 3. The terminal tube 3 is connected to the terminal rigid tube 4. The electrode material is platinum-iridium alloy, gold.

[0059] In a preferred embodiment of the present invention, the ablation catheter is a pulsed electric field ablation catheter, which is used to deliver and release pulsed ablation energy to the site to be ablated. That is, the ablation catheter is mainly used to perform ablation by applying a high voltage pulsed electric field to human tissue. More specifically, the ablation catheter of the present invention can be used for ablation of the heart and its surrounding tissues.

[0060] In pulsed electric field ablation, a high voltage is applied between the electrodes to perform discharge ablation, so the voltage is 1000 to 4000V, and therefore the electrode surface area must be sufficiently large, otherwise the local electric field strength will be too concentrated during discharge, resulting in an arc phenomenon. However, as mentioned above, the problem of adjustable annular distal end diameter must be considered, and therefore the electrodes are arranged as an electrode pair. A single electrode is spaced apart from another electrode by a certain relatively short distance. As a result, the two electrodes can form an electrode pair, and the pair of electrodes (electrode pair) can be considered equivalent to one electrode during discharge, so that the discharge effect of an electrode with a sufficiently large surface area can be exerted. At the same time, the electrode dimensions are not too large to affect the adjustment of the diameter of the annular distal end.

[0061] Meanwhile, the spacing between the two electrodes in the electrode pair is relatively close, and they can be used for measurement separately at the same time. Because the pulsed electric field energy output is relatively high and concentrated, it is required that the distance between the positive and negative electrodes to which high voltage is applied is as large as possible. However, if the electrode spacing is too large, the range of electrophysiological signals collected will be too large, which will affect the judgment of the local ablation effect. Therefore, after the ablation is completed, the electrophysiological signals are collected using the two electrodes in the electrode pair that are relatively close to each other, so that the judgment of the electrophysiological signals can be more accurate. The local electrical signals can be more precisely judged. To avoid too large electrode spacing, it is necessary to avoid introducing a wide range of electrophysiological signals, which will affect the judgment of the ablation effect.

[0062] Thus, simply stated, when used for pulsed electric field ablation, the ablation catheter is in ablation mode and the polarity of the two electrodes in each electrode pair is the same, which is equivalent to energizing one electrode, thereby acting as a discharge of one sufficiently large surface area electrode during ablation, while the polarity of adjacent electrode pairs is opposite.

[0063] On the other hand, when used for electrophysiological measurements, the ablation catheter is in measurement mode and the two electrodes in each electrode pair function independently, i.e., are used to collect electrophysiological signals independently, acting as two relatively closely spaced electrodes.

[0064] FIG. 4 is a schematic diagram of the traction assembly arrangement of the distal tube. As shown in FIG. 4, the annular distal tip 1 is arranged in the rigid distal tube 4. The rigid distal tube 3 is connected to the rigid distal tube 4 at a portion close to the proximal end that is not bent. A traction assembly 42 is arranged inside the rigid distal tube 4. The traction assembly 42 is fixed to the rigid distal tube 4. The bending of the distal tube 5 (see FIG. 14) can be achieved under the control of a push button 16 between the handle assembly 15 and the proximal tube 6. A positioning electrode 41 is provided on the rigid distal tube 4 and is used to align with the positioning sensors (e.g., positioning sensors 131, 132, 133 described below).

[0065] Figure 5 is a schematic diagram of the annular distal tip in a retracted state. Figure 6 is a schematic diagram of the arrangement of electrode pairs in the retracted state of the annular distal tip. Figure 10 is a schematic diagram of the tensile side of the annular distal tip. Figure 15 is a schematic diagram of the inside of the retraction control assembly of the annular distal tip.

[0066] As previously mentioned, there may be a knob 17 on the handle assembly 15. Rotating the knob 17 controls the contraction and recovery of the retraction rope, which results in a change in the annular diameter of the annular distal end.

[0067] 5, 6, 10, and 15, and more specifically, as shown in FIG. 15, when the knob 17 on the handle assembly 15 is operated, the slide block 171 moves the retraction rope 9. The retraction rope 9 is fixed to the slide block 171. The rotating core shaft 172 has an internal female thread that fits with the external thread on the slide block 171. When the knob 17 is rotated clockwise, the knob 17 drives and rotates the rotating core shaft 172, which moves the slide block 171 backward, pulling the retraction rope 9 and further achieving retraction of the annular distal end 1. When the knob 17 is rotated counterclockwise, the retraction rope 9 recovers and the diameter of the annular distal end 1 increases or recovers.

[0068] As mentioned above, in the natural state, the annular distal tip has a spiral ring shape with a ring diameter of 20-35 mm. There is a separation between the tip and the end of the annular distal tip 1, the separation distance being 1 / 5-1 / 4 of the annular circumference. As shown in Figures 5, 6 and 10, when the annular distal tip 1 is minimally contracted, the two electrode pairs 111 and 119 at the tip and end on the distal tube 3 do not overlap, further increasing safety. When the annular distal tip diameter is minimally contracted, the annular distal tip 1 has a closed ring shape in the annular cross section with a ring diameter of 12-15 mm, and the electrode pairs at the tip and end do not overlap. Figures 5 and 10 show the distal tube 3 and the electrode pairs (e.g. 111 and 119) as well as the distal rigid tube 4 or a portion thereof.

[0069] The ablation catheter according to the present invention further includes a support member disposed through the distal tube and the inside of the distal rigid tube, and a shrink rope disposed on the annular inner side of the support member. One end of the shrink rope is fixed to the injury prevention tip together with one end of the support member. When the shrink rope is shrunk, it pulls and deforms the support member to adjust the annular diameter of the annular distal end.

[0070] A schematic diagram of the support member is shown in FIG. 7. The support member 7 is annular. The shape of the annular distal end is mainly determined by the shape of the support member. The material of the support member is a memory alloy material with high elasticity, such as nickel titanium alloy (NiTi), which can instantly recover its original shape after removing the external force. In a preferred embodiment, the diameters of the support member tip 71 and the support member proximal end 72 are not the same. In order to realize the function of the diameter adjustment of the annular distal end, the diameter of the support member tip 71 is smaller than the diameter of the support member proximal end 72, and the diameter gradually increases from the tip to the proximal end. In order to realize the contraction of the annular distal end 1, the annular distal end 1 contracts under the action of the contraction rope 9, but if the tip rigidity is too large, the tip deformation and contraction cannot be realized. Therefore, the tip diameter is smaller than the proximal end and gradually increases, and the tip diameter is 1 / 3 to 4 / 5 of the proximal end diameter. The material of the shrink rope 9 is preferably a stainless steel wire rope that is flexible and has a relatively high tensile strength, and has a diameter of 0.10 to 0.15 mm. The flexible shrink rope 9 does not cause an increase in the stiffness of the annular distal end 1, and also avoids affecting the normal deformation of the ring. The shrink rope 9 may be a polyethylene rope (PE rope), which is soft and has a higher tensile strength. The shrink rope 9 will be described in further detail below.

[0071] Figure 8 is a schematic diagram of the interior of the annular distal tip, Figure 9 is a schematic diagram of the placement of a positioning sensor within the annular distal tip, and Figure 11 is a schematic cross-sectional view of the tip of the annular distal tip.

[0072] As shown in FIG. 8, a shrink rope 9 is provided on the annular inside of the support member 7, and the support member 7 can be deformed by the shrink rope 9, thereby changing the diameter of the annular distal end 1. That is, the annular diameter of the annular distal end 1 can be contracted. The support member 7 and the shrink rope 9 are both fixed in the damage prevention end 8 at the tip end of the annular distal end 1. As shown in FIG. 11, the outside of the support member 7 and the shrink rope 9 are covered by a protective tube 10. The protective tube 10 protects the members inside the distal tube 3 from being affected when the shrink rope 9 shrinks, and at the same time, makes the shrink rope 9 shrink more smoothly. The material of the protective tube 10 is preferably polytetrafluoroethylene pipe material.

[0073] In a preferred embodiment of the invention, a positioning sensor may be provided below the electrode pair such that the positioning sensor is located inside the distal tube.

[0074] As shown in FIG. 9, the first positioning sensor 131 is located at the tip of the annular distal tip 1 and below the first electrode pair 111. The second positioning sensor 132 is located at the middle position of the annular distal tip 1, for example, below the electrode pair at the middle position of the annular distal tip 1, for example, below the sixth electrode pair 116. The third positioning sensor 133 is located inside the distal rigid tube 4. These positioning sensors, in combination with the positioning electrode 41 (FIGS. 2 and 4) and the electrode on the distal tube 3, can display the shape of the annular distal tip 1 and the positional relationship of the electrodes, making it easy to observe whether the electrodes are overlapping, and better ensuring the safety of the electrodes. The magnetic positioning function can monitor the position where overlapping is most likely to occur, thereby limiting the energy output under extreme conditions. The dimension (e.g., referred to as "length") of the position sensor in the arcuate extension direction of the distal tube is equal to the sum of the dimensions ("length" or "width" in the arcuate extension direction of the distal tube) and the distance between the two annular electrodes, i.e., the dimension of one electrode pair (the width of one electrode pair in the arcuate extension direction of the distal tube), and is located directly below the electrode pair. Such a design is to avoid increasing the rigidity of the annular part. The position sensor has a cylindrical structure and a hollow center. This allows the support member 7 to pass through the center of the cylindrical structure and the position sensor to be fixed to the support member 7. The position sensor is a cylindrical structure with a spiral winding of copper lead wire, which has a certain elasticity, and after being protected and fixed by the highly elastic polyurethane material on the outside, a position sensor that can be freely deformed and does not affect its performance is formed, and is suitable for use in annular adjustable annular rings.

[0075] As shown in FIG. 11, the positioning sensors are fixed to the support member 7, respectively. The first positioning sensor 131 and the protection tube 10 (including the support member 7 and the shrink rope 9 in the protection tube 10) are fixed to the sheath tube 14 for stable fixation thereon. Similarly, the second positioning sensor 132 and the protection tube 10 may be fixed to the sheath tube 14. The material of the sheath tube 14 is preferably a high-elasticity polyurethane tube material having high elasticity and being easy to bond. The support member 7, the shrink rope 9 and the protection tube 10 are fixed to the damage prevention tip 8. In the schematic of FIG. 11, the positioning sensor 131 is disposed at the tip of the annular distal end 1, below the first pair of annular electrodes 11 and 12. The dimension (e.g., referred to as the "length") of the positioning sensor 131 in the arcuate extension direction of the distal tube is equal to the dimensions (the "length" or "width" in the arcuate extension direction of the distal tube) of the two annular electrodes 11 and 12 and the spacing between them, i.e., the dimensions of one electrode pair, and is disposed directly below this pair of annular electrodes 11 and 12.

[0076] 11 , the first positioning sensor 131 is fixed to the outer periphery of the protective tube 10. Since the first positioning sensor 131 has a cylindrical structure with a hollow center, the protective tube 10 can penetrate the center of the cylindrical structure of the first positioning sensor 131. In other words, the support member 7 penetrates the center of the cylindrical structure of the first positioning sensor 131.

[0077] Similarly, the second position sensor 132 may be fixed to the outer periphery of the protective tube 10. Since the second position sensor 132 has a cylindrical structure and is hollow at the center, the protective tube 10 can penetrate the center of the cylindrical structure of the second position sensor 132. In other words, the support member 7 penetrates the center of the cylindrical structure of the second position sensor 132.

[0078] Fig. 12 is a schematic cross-sectional view of the distal end tube, and Fig. 14 is a schematic view of the bending effect of the distal end tube.

[0079] As described above, the ablation catheter according to the present invention may further include a push button 16 disposed between the handle assembly 15 and the proximal end tube 6. According to a preferred embodiment of the present invention, the push button 15 is connected to one end of a traction assembly 42 disposed in the distal end tube 5. The other end of the traction assembly 42 is connected to the terminal rigid tube 4. By pressing the push button 16, the tightening or loosening of the traction assembly 42 can be controlled, thereby realizing bending of the distal end tube 5.

[0080] As shown in FIG. 12 and FIG. 14, by pressing the push button 16, the bending of the distal end tube 5 can be controlled, and the annular distal end 1 can be helped to reach the target position. As shown in FIG. 12, the distal end tube 5 is a multi-cavity tube structure, and the shrink rope 9 of the annular distal end 1 is disposed in the middle cavity. Since it is disposed in the middle cavity, when the shrink rope 9 shrinks, it does not affect the curvature of the distal end tube 5, and does not pull the bending of the distal end tube 5. The pulling assembly 42 is disposed on the side of the distal end tube 5 to facilitate the bending of the distal end tube 5 without affecting the middle shrink rope 9. The shrink rope 9 is in the middle, and does not cause a relative movement of the shrink rope 9 even when the distal end tube 5 is bent or stretched. This avoids the problem that the shrinkage of the annular distal end 1 and the bending of the distal end tube 5 may interfere with each other.

[0081] 1 shows the same components and configurations as in FIG. 1, i.e., annular distal tip 1, terminal rigid tube 4, distal end tube 5, proximal end tube 6, handle assembly 15, connector 18 and connector 19, in addition to push button 16 and knob 17. Those skilled in the art will appreciate that the above-mentioned components and configurations are combined to form one preferred embodiment of an ablation catheter according to the present invention, but that an ablation catheter according to the present invention is not limited to including all of these components and configurations.

[0082] Also, as mentioned above, the connector of the ablation catheter shown in Figures 1 and 14 includes at least two types of connectors: connector 18 for transmitting positioning information between the catheter and the device, and connector 19 for transmitting ablation energy between the catheter and the device. Referring to the depiction in Figure 11, it can be seen that connector 18 is connected to a position sensor via a first cable for transmitting positioning information. Connector 19 is connected to the ring electrodes on each electrode pair respectively via a second cable for transmitting ablation energy. Connector 19 and the second cable can also be used to collect electrophysiological measurement signals while the ablation catheter is in a measurement mode.

[0083] Application embodiment Specific uses of the annular, variable diameter distal tip ablation catheter of the present invention according to application embodiments are described in further detail below.

[0084] Figure 16 is a schematic diagram of an application according to an embodiment of the present invention. Figure 17 is a schematic diagram of another application according to an embodiment of the present invention. The application embodiment of FIG. 16 and FIG. 17 may include the following operation steps. Step 1: As shown in FIG. 16, the diameter of the annular distal end 1 is reduced to a small diameter annular distal end 1 and inserted into the luminal structure 20. Step 2: Measure electrophysiological signals inside the ductal structure 20, and construct a physical model of the ductal structure 20. Step 3: As shown in FIG. 17, the diameter of the annular distal end 1 is increased in a controlled manner so that the electrode fits snugly against the luminal structure 20. Step 4: Discharge ablation, voltage amplitude is 1000-4000V. After ablation, electrophysiological signals are collected by two electrodes in the electrode pair. The immediate ablation effect can be determined by comparing the changes in the electrophysiological signals until the electrical activity of the luminal structure 20 is completely isolated.

[0085] FIG. 18 is a schematic diagram of an electric field distribution when electric field energy is emitted from the ablation catheter of the present invention.

[0086] As shown in FIG. 18, when a pulse discharge is performed, all the electrodes on the ablation catheter form a continuous ablation region in the myocardial tissue 21, that is, the electric field region 22 by the discharge shown in the figure. In general, the myocardial ablation effectiveness threshold is 400V / CM. In the electric field region 22, the voltage intensity is all greater than 400V / CM, and this threshold is reached, and effective myocardial ablation can be performed in this continuous region. The number of electrode pairs is 2N+1 (N is a positive integer). Each electrode pair is composed of two ring electrodes, and as shown in FIG. 18, the number of electrode pairs is 9. Both the first electrode pair 111 and the ninth electrode pair 119 are composed of two fine ring electrodes. The ring electrodes are preferably gold or platinum electrodes, and the dimensions (the "length" or "width" in the arcuate extension direction of the distal tube) are 0.50 to 1.5 mm. The clearance distance between the ring electrodes is 1-3mm, the clearance distance between the ring electrode pairs is 3-6mm, and the pulse electric field width value applied is 1000-4000V. In order to improve the ablation efficiency, a continuous ablation area is formed when the electrodes discharge, and the ablation leakage point is prevented. Based on the electric field distribution and mechanical design of the electrodes, ensure that the surface area of ​​the electrode pairs is large enough, and under the premise that the spacing between the electrode pairs is appropriate, a continuous ablation area is formed during discharge ablation, and the ring adjustable function is ensured, and the following relationship exists:

[0087] [Number 1] (2×L+d)×k=D and S>D

[0088] where L is the width (sometimes called "length") of the annular electrodes in the direction of arcuate extension of the distal tube, d is the spacing between the two annular electrodes in one electrode pair, D is the spacing between adjacent electrode pairs, S is the diameter of each annular electrode, and k is a correction coefficient having a value between 0.7 and 1.4 (k=0.7-1.4). As mentioned above, in a preferred embodiment, L has a value between 0.50 and 1.5 mm, d has a value between 1 and 3 mm, and D has a value between 3 and 6 mm.

[0089] Although various elements and components of the ablation catheter are mentioned in the above various embodiments, those skilled in the art should understand that these elements and components can be arbitrarily combined in the ablation catheter to perform their respective functions and achieve the corresponding functions, unless expressly excluded in the above specification or permitted or impossible in practice. None of the above embodiments or examples can limit the scope of the present invention.

[0090] Electrode function control method The ablation catheter of the present invention can be used in ablation mode and measurement mode respectively, so that the electrodes and electrode pairs of the ablation catheter can be controlled accordingly, and can exert different effects and achieve different functions in different modes.

[0091] Specifically, the present invention proposes a method for controlling the function of the electrode pairs of the ablation catheter of the present invention. The ablation catheter is specifically a pulsed electric field ablation catheter used for ablation of the heart and its surrounding tissues. According to the method proposed by the present invention, in the ablation mode of the catheter, electric field energy of the same polarity is transmitted to the two electrodes with a relatively small distance in each electrode pair, and the two electrodes in the electrode pair are equivalent to one electrode with a relatively large size or surface area to apply voltage to the corresponding tissue, and electric field energy of opposite polarity is transmitted to the adjacent electrode pair, thereby realizing the pulsed electric field ablation function. Meanwhile, in the measurement mode of the catheter, the two electrodes with a relatively small distance in each electrode pair are used independently, i.e., the two electrodes in each electrode pair are used to collect electrophysiological signals independently, thereby realizing the electrophysiological measurement function.

[0092] Computer program or computer program product and computer readable medium Also, those skilled in the art should appreciate that the methods disclosed herein can be implemented as computer programs. The above methods are implemented by one or more programs including instructions to execute corresponding algorithms on a computer or processor. These programs can be stored and provided to a computer or processor using various non-transitory computer readable media. Non-transitory computer readable media include various tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., floppy disks, tapes, hard drives, etc.), magneto-optical recording media (e.g., magneto-optical disks, etc.), CD-ROM (compact disk read-only memory), CD-R, CD-R / W, and semiconductor memory (e.g., ROM, PROM (programmable ROM), EPROM (rewritable PROM), flash ROM, RAM (random access memory), etc.). Furthermore, these programs can be provided to a computer by using various temporary computer readable media. Examples of temporary computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer readable media can be used to provide the programs to a computer via wired or wireless communication paths, such as wires and optical fibers.

[0093] For example, according to one embodiment of the present disclosure, a computer-readable medium stores instructions executable by a processor that, when executed by the processor, causes the processor to perform a method for controlling function of an electrode pair on the ablation catheter.

[0094] According to the subject matter of the present disclosure, it is also proposed a computer program or computer program product which, when said computer program is executed, implements a method for controlling the functioning of electrode pairs on said ablation catheter.

[0095] In addition, the present invention also relates to a computing device or system including a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, it realizes a method for controlling the function of an electrode pair on the ablation catheter.

[0096] Beneficial effects In summary, the ablation catheter according to the present invention has at least the following beneficial effects. 1. The design of the pulse catheter with adjustable size of the annular distal end is suitable for various tract structures, and the adjustable design is advantageous for the electrodes on the annular distal end to better fit the tissue structure. 2. The design of the electrode pair makes it more convenient to adjust the diameter of the annular distal end under the premise of ensuring the efficacy and safety of ablation. At the same time, the electrode pair is used to make the collection of electrophysiological signals more accurate, and avoids the electrode spacing being too large to affect the judgment of changes in electrical signals. 3. The electrode design of the above invention integrates the electrode pair into one electrode for ablation, and separates the electrode pair into two electrodes for measurement, fully achieving both the effectiveness of pulsed electric field ablation and the accuracy of electrophysiological measurement. 4. A positioning sensor installation method is proposed that can be freely deformed without affecting performance. It is applied to the annular part of the catheter with adjustable diameter, which can provide real-time display of the shape and electrode spacing during the operation of the ablation catheter, guide the surgeon to perform accurate ablation operation, and at the same time monitor the electrode spacing to increase safety. 5. High voltage pulse energy can be delivered precisely and effectively to the target tissue, significantly shortening the operation time. High voltage pulse energy can selectively ablate the target tissue, reducing complications. 6. The catheter has the functions of measurement, modeling and ablation, which can save operation time and cost.

[0097] The embodiments of the present invention are not limited to the above embodiments, and those skilled in the art may make various changes and improvements in the form and details of the present invention without departing from the spirit and scope of the present invention, all of which are deemed to be within the scope of protection of the present invention. [Explanation of symbols]

[0098] 1-Annular Distal End 2-electrode pair 3-End tube 4-terminal rigid tube 41-Positioning electrode 42-Towing Assembly 5-Distal end tube 6-Proximal end tube 7-Supporting member 71-Support member tip 72-Support member proximal end 8- Damage prevention tip 9- Contraction Rope 10-Protection tube 11-Ring electrode 12-Ring Electrode 131-First position sensor 132-Second position sensor 133-Third position sensor 14-Sheath tube 15-Handle Assembly 16-Push Button 17-Nobu 171-Slide Block 172-Rotating core shaft 173-Slide groove 18-First Connector 19-Second Connector 20-luminal structure 111-First electrode pair 112-Second electrode pair 113-Third electrode pair 114-Fourth electrode pair 115-5th electrode pair 116-6th electrode pair 117-7th electrode pair 118-8th electrode pair 119-Ninth electrode pair 21- Myocardial tissue 22- Electric field region formed by discharge

Claims

1. An ablation catheter, The annular distal end (1) includes an arcuate distal tube (3); An ablation catheter, characterized in that a plurality of electrode pairs (2) are arranged at intervals along the arcuate extension direction of the terminal tube, and each of the plurality of electrode pairs (2) surrounds the terminal tube (3).

2. 2. The catheter of claim 1, wherein the number of electrode pairs (2) is 2N+1, where N is a positive integer.

3. 2. The catheter of claim 1, wherein each electrode pair (2) includes two annular electrodes (11, 12) surrounding the distal tube (3), each annular electrode having a width L in the arcuate extension direction of the distal tube, a distance d between the two annular electrodes in one electrode pair, a distance D between adjacent electrode pairs, and a diameter S of each annular electrode, satisfying the following conditions: [Number 1] S>D=(2×L+d)×k, Here, k is a correction coefficient, and k is a value between 0.7 and 1.

4.

4. 4. The catheter of claim 3, wherein L has a value between 0.50 and 1.5 millimeters, d has a value between 1 and 3 millimeters, and D has a value between 3 and 6 millimeters.

5. The catheter of claim 3 , wherein the annular electrode is a helical electrode.

6. The catheter of claim 5, wherein the helical electrode is a wound electrode lead wire.

7. 6. The catheter according to claim 5, wherein the helical electrode is an electrode formed by cutting a ring electrode into a helical shape.

8. 2. The catheter according to claim 1, wherein the catheter is a pulsed electric field ablation catheter and is used to deliver and release pulsed ablation energy to a site intended for ablation.

9. The catheter according to claim 8, characterized in that the catheter is for ablation of the heart and surrounding tissue.

10. 9. The catheter of claim 8, wherein for pulsed electric field ablation, the polarity of the two electrodes of each electrode pair is the same, which is equivalent to applying a voltage to one electrode, and the polarity of adjacent electrode pairs is opposite.

11. 9. The catheter of claim 8, wherein for electrophysiological measurements, two electrodes of each electrode pair are used independently to acquire electrophysiological signals.

12. The catheter according to claim 10, wherein the amplitude of the voltage applied to each of the electrode pairs is 1000 to 4000 V.

13. 2. The catheter according to claim 1, characterized in that a positioning sensor (131, 132) is arranged below the electrode pair (2) and located inside the distal tube (3).

14. The catheter according to claim 13, characterized in that the length of the positioning sensor (131, 132) in the arcuate extension direction of the distal tube is equal to the width of the electrode pair (2) in the arcuate extension direction of the distal tube.

15. The catheter according to claim 14, characterized in that the length of the positioning sensor (131, 132) in the arcuate extension direction of the distal tube is equal to the sum of the width and the spacing between each of the two annular electrodes in the electrode pair in the arcuate extension direction of the distal tube.

16. 14. The catheter of claim 13, wherein the positioning sensors include a first positioning sensor (131) and a second positioning sensor (132), the first positioning sensor (131) being positioned below a first electrode pair from a tip of the annular distal end, and the second positioning sensor (132) being positioned below an electrode pair at an intermediate position of the annular distal end.

17. The catheter of claim 1 , wherein the annular diameter of the annular distal end is collapsible.

18. 18. The catheter of claim 17, wherein the annular distal tip is helical in nature, has an annular diameter of 20-35 millimeters, has a separation between the leading and trailing ends of the annular distal tip, and the separation distance is 1 / 5-1 / 4 of the annular circumference.

19. 19. The catheter of claim 18, wherein when the annular distal tip is minimally retracted, the annular diameter is between 12 and 15 millimeters, the annular distal tip presents a closed annulus in annular cross-section, and the electrode pairs on the tip and end of the annular distal tip do not overlap.

20. One end of the terminal tube (3) is a free end, which is located at the tip of the annular distal end (1), and has a damage prevention tip (8) at the free end, and the other end of the terminal tube (3) is a fixed end, and the catheter further comprises: a terminal rigid tube (4) one end of which is connected to the fixed end of the terminal tube body (3); a distal end tube (5) whose one end is connected to the other end of the terminal rigid tube (4); a proximal end tube (6) whose one end is connected to the other end of the distal end tube (5); a handle assembly (15) one end of which is connected to the other end of the proximal end tube (6); and a connector (18, 19) connected to the other end of the handle assembly (15).

21. The support member (7) is disposed penetrating the inside of the terminal tube body (3) and the terminal rigid tube (4) and is made of a memory alloy material; A shrink rope (9) is disposed inside the annular portion of the support member (7), and one end of the shrink rope is fixed to the damage prevention tip (8) together with one end of the support member (7); The catheter according to claim 20, characterized in that, when the shrink rope (9) shrinks, it pulls and deforms the support member (7) to adjust the diameter of the annular distal end (1).

22. The catheter according to claim 21, further comprising a protective tube (10) encasing the outside of the support member (7) and the shrink rope (9).

23. 22. The catheter of claim 21, further comprising a knob (17) on the handle assembly (15), the knob (17) being configured to control contraction and recovery of the contraction rope (9) by rotation.

24. The catheter according to claim 22, characterized in that a positioning sensor (131, 132) is fixed to the outer periphery of the protective tube (10), the positioning sensor (131, 132) is a cylindrical structure, and the protective tube passes through the center of the cylindrical structure.

25. The catheter according to claim 24, characterized in that the positioning sensor (131, 132) and the protective tube (10) are fixed by a sheath tube (14).

26. The catheter further comprises: The catheter of claim 20, further comprising a push button (16) disposed between the handle assembly (15) and the proximal end tube (6), the push button (15) being connected to one end of a traction assembly (42) disposed in the distal end tube (5), the other end of the traction assembly (42) being connected to the terminal rigid tube (4), and bending of the distal end tube (5) being achieved by pressing the push button (16) to control the tightening or loosening of the traction assembly (42).

27. 27. The catheter of claim 26, wherein the traction assembly (42) is laterally disposed within the distal end tube (5).

28. 21. The catheter of claim 20, further comprising a positioning electrode (41) arranged on the distal rigid tube (4) and a third positioning sensor (133) arranged inside the distal rigid tube (4).

29. The connectors (18, 19) are a first connector (18) configured to be connected to the positioning sensor (131, 132, 133) via a first cable and to transmit positioning information; and a second connector (19) configured to connect to the annular electrodes on each electrode pair respectively via a second cable and to transmit ablation energy.

30. 10. A method for controlling the function of an electrode pair on an ablation catheter according to claim 1, comprising: The ablation catheter is a pulsed electric field ablation catheter used for ablation of the heart and its surrounding tissues, In an ablation mode of the catheter, electric field energy of the same polarity is transmitted to two electrodes in each electrode pair, voltage is applied to the corresponding tissue as if the two electrodes in the electrode pair were one electrode, and electric field energy of opposite polarity is transmitted to adjacent electrode pairs to realize a pulsed electric field ablation function; and 2. The method for controlling the function of an electrode pair on an ablation catheter as described in claim 1, characterized in that in a measurement mode of the catheter, electrophysiological signals are collected independently by two electrodes in each electrode pair to realize an electrophysiological measurement function.

31. A computer-readable medium, storing instructions executable by a processor; 31. A computer readable medium, the instructions which, when executed by a processor, cause the processor to perform a method of controlling function of an electrode pair on an ablation catheter as recited in claim 30.

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