Ablation catheter

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 specifically to an ablation catheter having an annular distal end with adjustable diameter. 【Background Art】 【0002】 Conventionally, the methods commonly used in clinical treatment of arrhythmias such as atrial fibrillation are two types: radiofrequency (RF) ablation and cryoablation. The success of ablation mainly depends on the quality and appropriateness of the damage that occurs during the surgical process. The damage must either destroy the tissue causing the arrhythmia or sufficiently interfere with or isolate the abnormal electrical conduction within the myocardial tissue. However, excessive ablation affects the surrounding healthy tissues and nerve tissues. The disadvantages of radiofrequency ablation are that the ablation operation time is relatively long, the requirements for the catheter operation level of the operator are relatively high, and because it is thermal damage, it is accompanied by pain during ablation, and the problem of pulmonary vein stenosis is likely to occur after the operation. When radiofrequency energy is applied to the target tissue, it affects the 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 a risk of causing blisters in the tissue, which leads to the problem of embolism. For cryoablation, if the cryoballoon and the pulmonary vein are closely adhered, annular ablation isolation can be completed in one or several times, and the patient can feel no pain and the operation time can be shortened, but the damage rate of cryoablation to the phrenic nerve is relatively high. 【0003】 Pulsed electric field technology allows for the short-duration application of high voltage to tissue, generating localized high electric fields of several hundred volts per centimeter. These localized high electric fields disrupt cell membranes by creating pores (the cell membranes change and undergo a phenomenon called "penetration"). Because different tissue cells have different thresholds for voltage penetration, pulsed electric field technology allows for the selective treatment of cardiomyocytes (which have a relatively low threshold) without affecting other non-target cell tissues (e.g., nerves, esophagus, blood vessels, blood cells, etc.). Simultaneously, because the energy release time is extremely short, pulsed technology does not produce thermal effects, avoiding problems such as tissue scabbing and pulmonary vein stenosis. 【0004】 However, the voltage of high-voltage pulses is relatively high, and it is necessary to avoid excessive energy concentration between electrodes, which can easily lead to safety accidents. Therefore, it is necessary to strengthen the insulation of the electrodes and the inside of the catheter. Conventional ablation catheters that perform ablation with high-voltage pulses tend to cause ionization between electrodes, and the ablation time with high-voltage pulses is short, requiring even more precise positioning. 【0005】 Atrial fibrillation (AF) is a common persistent arrhythmia that seriously endangers human health and affects quality of life. The reason why the pulmonary veins are the most common localized lesion in atrial fibrillation is the presence of the pulmonary vein myocardial sleeve. A colony of cardiomyocytes is located between the intima and adventitia of the pulmonary veins, wrapping around the pulmonary veins in a sleeve-like fashion from the atrium to the lung, and is called the myocardial sleeve. The cells that form the myocardial sleeve have a different origin from the atrial muscle and have different electrophysiological properties, so abnormal excitability substrates are formed. The atrial muscle surrounding the pulmonary veins also contains arrhythmia substrates that trigger or maintain AF, just like the pulmonary veins, so the myocardial tissue surrounding the pulmonary veins may be ablated during ablation isolation. 【0006】 Conventional methods involve sequential point ablation of the pulmonary vein vestibule to form an annular separation zone. This method results in long operating times, places a significant burden on both the patient and the physician, and frequently leads to leakage points that cause recurrence. Therefore, there is an urgent need to design a catheter that can rapidly ablate and isolate the pulmonary vein vestibule in a single procedure. 【0007】 Conventional annular electrode catheters have a fixed shape and dimensions, making it difficult to achieve good contact and manipulation with structural tissues of different lumen dimensions. 【0008】 Therefore, an ablation catheter with an annular distal end is required, and the annular distal end has the capability to adjust its diameter, allowing it to adapt to different tissue structures, ensure good contact, and form a closed annular ablation zone during ablation discharge. [Overview of the Initiative] 【0009】 The present invention provides an ablation catheter having an annular distal end. On the one hand, the diameter of the annular distal end is adjustable, allowing adaptation to different tissue structures and ensuring good contact. On the other hand, an electrode pair is positioned at the annular distal end to adapt to deformation and contraction caused by the adjustment of the annular distal end's diameter. Furthermore, the annular electrodes in the electrode pair act as a pair in ablation mode and act individually in measurement mode. 【0010】 A first aspect of the present invention provides an ablation catheter. The ablation catheter has an annular distal end, the annular distal end includes an arc-shaped terminal tube. Multiple electrode pairs are arranged at intervals along the arc-shaped extending direction of the terminal tube, and each of the multiple electrode pairs surrounds the terminal tube. 【0011】 Preferably, the number of electrode pairs is 2N+1, where N is a positive integer. 【0012】 In an ablation catheter according to a first aspect of the present invention, each electrode pair includes two annular electrodes surrounding a terminal tube, and the width of the terminal tube of each annular electrode in the arc-extending direction is L. The distance between the two annular electrodes in one electrode pair is d, the distance between adjacent electrode pairs is D, the diameter of each annular electrode is S, and 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 is a value of 0.50 to 1.5 millimeters, d is a value of 1 to 3 millimeters, and D is a value of 3 to 6 millimeters. 【0014】 Preferably, the annular electrode may be a helical electrode. The helical electrode may be formed by winding an electrode lead wire, or by cutting an annular electrode to form a helical electrode. 【0015】 Preferably, the catheter is a pulsed electric field ablation catheter, used to transmit and release pulsed ablation energy to the site to be ablated. 【0016】 Preferably, the catheter is used for ablation of the heart and surrounding tissues. 【0017】 When used in pulsed field ablation, the polarity of the two electrodes in each electrode pair is the same, which is equivalent to applying a voltage to a single electrode, while 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 collect electrophysiological signals. 【0019】 Preferably, the amplitude of the voltage applied to each electrode pair is 1000 to 4000 V. 【0020】 In an ablation catheter according to a first aspect of the present invention, a positioning sensor is placed below the electrode pair and located inside the terminal tube. 【0021】 Preferably, the length of the end tube of the positioning sensor in the arc-shaped extension direction is equal to the width of the end tube of the electrode pair in the arc-shaped extension direction. Specifically, the length of the end tube of the positioning sensor in the arc-shaped extension direction is equal to the sum of the width and the distance between them in the arc-shaped extension direction at the end tube of each of the two ring electrodes in the electrode pair. 【0022】 Preferably, the positioning sensor includes a first positioning sensor and a second positioning sensor. The first positioning sensor is positioned below the first pair of electrodes from the tip of the distal annular end. The second positioning sensor is positioned below the pair of electrodes at an intermediate position of the distal annular end. 【0023】 In an ablation catheter according to a first aspect of the present invention, the annular diameter of the distal annular end can be reduced. 【0024】 In its natural state, the distal annular end can be spiral in shape, and its annular diameter is 20 to 35 millimeters. The tip and end of the distal annular end are separated, and the distance of this separation is 1 / 5 to 1 / 4 of the annular circumference. 【0025】 When the distal annular end is contracted to its minimum extent, the annular diameter is 12 to 15 millimeters. The distal annular end exhibits a closed ring shape in its annular cross-section, and the electrode pairs at the tip and end of the distal annular end do not overlap. 【0026】 In the ablation catheter according to the first aspect of the present invention, one end of the distal tube body 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 distal tube body is a fixed end. The catheter can further include the following. A distal rigid tube, one end of which is connected to the fixed end of the distal tube body. A distal end tube body, one end of which is connected to the other end of the distal rigid tube. A proximal end tube body, one end of which is connected to the other end of the distal end tube body. A handle assembly, one end of which is connected to the other end of the proximal end tube body. A connector, which is connected to the other end of the handle assembly. 【0027】 Preferably, the catheter further includes the following. A support member, which is arranged to penetrate through the inside of the distal tube body and the distal rigid tube and is made of a shape memory alloy material. A contraction rope, which is arranged inside the annular support member, and one end of which is fixed to the damage prevention tip together with one end of the support member. When the contraction rope contracts, it pulls and deformes the support member to adjust the diameter of the annular distal end. 【0028】 Preferably, the catheter further includes a protective tube that wraps the outside of the support member and the contraction rope. 【0029】 Preferably, the handle assembly has a knob. The knob is installed to control the contraction and recovery of the contraction rope by rotation. 【0030】 Preferably, a positioning sensor is fixed on the outer periphery of the protective tube. The positioning sensor has a cylindrical structure, and the protective tube penetrates through the center of the cylindrical structure. 【0031】 Preferably, the positioning sensor and the protective tube are fixed with a sheath tube. 【0032】 Preferably, the ablation catheter according to the first aspect of the present invention may further include a push button positioned between the handle assembly and the proximal end tube. The push button is connected to one end of a traction assembly positioned within the distal end tube, the other end of which is connected to the end rigid tube, and pressing the push button controls the tightening of the traction assembly, thereby enabling bending of the distal end tube. 【0033】 Preferably, the traction assembly is positioned on the side of the distal end tube. 【0034】 In an ablation catheter according to a first aspect of the present invention, a positioning electrode can be installed on the terminal rigid tube, and a third positioning sensor can be installed inside the terminal rigid tube. 【0035】 In an ablation catheter according to a first aspect of the present invention, the connector includes: a first connector which is connected by a first cable to a positioning sensor and is arranged to transmit positioning information; and a second connector which is connected by a second cable to annular electrodes on each electrode pair and is arranged to transmit ablation energy. 【0036】 A second aspect of the present invention provides a method for controlling the function of an electrode pair on an ablation catheter according to the first aspect of the present invention. The ablation catheter is a pulsed electric field ablation catheter used for ablation of the heart and surrounding tissues. The method includes the following: In the catheter ablation mode, electric field energy of the same polarity is transmitted to the two electrodes in each electrode pair, treating the two electrodes in the electrode pair as equivalent to a single electrode, applying a voltage to the corresponding tissue, and transmitting electric field energy of opposite polarity to adjacent electrode pairs to realize a pulsed electric field ablation function. In the catheter measurement mode, electrophysiological signals are independently collected by the two electrodes in each electrode pair to realize an electrophysiological measurement function. 【0037】 A third aspect of the present invention provides a computer-readable medium for which a processor can store commands that, when executed by the processor, causes the processor to perform a method for controlling the function of an electrode pair of an ablation catheter according to a second aspect of the present invention. 【0038】 As already mentioned in the preamble, conventional fixed-diameter annular pulse ablation catheters cannot achieve good contact with the lumen structure. The diameter is too large and cannot penetrate the lumen structure. The diameter is too small and cannot achieve good contact with the lumen structure, which affects the efficiency and effectiveness of the ablation. At the same time, pulse electric field ablation requires a large single electrode area (the length or width of the electrode should be as large as possible) to avoid causing safety risks due to excessive concentration of the electric field, and the diameter of the annular catheter structure needs to be adjustable. If the electrode area is large and the electrode length or width is even larger, it is not applicable to adjusting the annular diameter. Since variable diameter requires compressive changes to the shape of the annular part, if the electrode dimensions are too large, the length of the locally rigid part of the annular catheter increases, making it difficult to deform and shrink the annular catheter. 【0039】 To ensure the safety of pulsed field ablation, the electrode spacing used in pulsed ablation is generally designed to be relatively large. However, excessively large electrode spacing makes it easy to introduce other interfering signals when acquiring electrophysiological signals, making it difficult to accurately acquire local electrical signals, which can affect the surgeon's analysis and judgment, and thus impact surgical efficiency. For accurate measurement of electrophysiological signals, even smaller electrodes and smaller electrode spacing are desirable, which enables more precise measurements. 【0040】 Considering these factors, the present invention proposes employing an electrode pair. In this way, when used as an ablation electrode, the pair of electrodes can be made to act in the same way as a single electrode. When used as a measurement electrode, the two electrodes in the electrode pair are used independently. The design of the electrode pair is more convenient for adjusting the annular distal end diameter while ensuring the effectiveness and safety of ablation, and at the same time, the electrode pair is more accurate in acquiring electrophysiological signals and avoids the interference caused by excessively large electrode spacing affecting the judgment of changes in electrical signals. 【0041】 Positioning sensors are useful for positioning and morphological indication of annular catheters. Because the annular portion, whose diameter can be adjusted, requires significant compressive deformation, conventional positioning sensors have relatively high rigidity and are not easily deformed in accordance with the deformation of the annular portion. However, without positioning sensors, annular pulse catheters pose an extremely high safety risk, as the overlapping of electrodes of different polarities can cause ignition problems, and ignition can burn cardiac tissue. 【0042】 Therefore, in a preferred embodiment of the present invention, a method for installing a positioning sensor that can be freely deformed and does not affect performance is proposed and applied to an annular portion that can adjust the diameter of the catheter. [Brief explanation of the drawing] 【0043】 The present invention can be better understood in connection with the following detailed description and accompanying drawings, where similar elements are numbered in a similar manner. [Figure 1] This is a schematic diagram of the ablation catheter according to the present invention. [Figure 2] This is a schematic diagram of the natural state of the distal end of the ring. [Figure 3] This is a schematic diagram of the electrode pair arrangement in the natural state of the distal annular end. [Figure 4] This is a schematic diagram showing the arrangement of the traction assembly for the distal end tube. [Figure 5] This is a schematic diagram of the contracted state of the distal annular end. [Figure 6]This is a schematic diagram of the electrode pair arrangement in the contracted state of the distal annular end. [Figure 7] This is a schematic diagram of the support member. [Figure 8] This is a schematic internal view of the distal annular end. [Figure 9] This is a schematic diagram showing the arrangement of the positioning sensors at the distal end of the annular section. [Figure 10] This is a schematic tensile side view of the distal annular end. [Figure 11] This is a schematic diagram of the tip cross-section of the distal annular end. [Figure 12] This is a schematic cross-sectional view of the distal end tube. [Figure 13] This is a schematic diagram showing a helical electrode instead of a ring electrode. [Figure 14] This is a schematic diagram illustrating the bending effect of the distal end tube. [Figure 15] This is a schematic internal diagram of the contraction control assembly at the distal annular end. [Figure 16] This figure shows an example of an application of an embodiment of the present invention. [Figure 17] This figure shows another application example of the embodiment of the present invention. [Figure 18] This is a schematic diagram of the electric field distribution during electric field energy release using the ablation catheter of the present invention. [Modes for carrying out the invention] 【0044】 The technical solutions of the present invention will be described in more detail below using embodiments and in conjunction with the attached drawings, but the present invention is not limited to the following embodiments. 【0045】 Ablation catheter Figure 1 is a schematic diagram of the ablation catheter according to the present invention. As shown in Figure 1, the ablation catheter according to the present invention includes, in its overall structure, sequentially from distal to proximal, an annular distal end 1, a terminal rigid tube 4, a distal end tube 5, a proximal end tube 6, a handle assembly 15, connectors 18 and 19. The annular distal end 1 is located at the most distal end of the catheter. The terminal rigid tube 4 is used to connect the annular distal end 1 and the distal end tube 5. The terminal rigid tube 4 is preferably made of a polyether ether ketone polymer material with high material hardness. The distal end tube 5 is located between the proximal end tube 6 and the terminal rigid tube 4. The distal end tube 5 is bent under the operation of the handle assembly 15 and is used to bring the annular distal end 1 to the desired site. The proximal end tube 6 is used to connect the distal end tube 5 and the handle assembly 15. The connectors of the ablation catheter shown in Figure 1 include at least two types of connectors. Specifically, connector 18 is used to transmit positional 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 Figure 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 language of this disclosure, “distal end” and “proximal end” refer to the catheter operator; for example, 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. Furthermore, “tip” and “terminal end” generally mean the free end and the fixed end (or “connecting end”). 【0048】 Those skilled in the art will understand that while the elements and components described above are combined to form one preferred embodiment of the ablation catheter according to the present invention, the ablation catheter according to the present invention is not limited to including all of these elements and components. 【0049】 Figure 2 shows a schematic diagram of the natural state of the annular distal end. As shown in Figure 2, the annular distal end has an outer diameter of 20-35 mm in its natural state and exhibits a "C" shape. The tip of the annular distal end is a damage-preventing tip 8, and the end is a rigid end, with a certain distance separating the tip and the end, this separation distance being approximately 1 / 4 to 1 / 5 of the circular structure. The annular distal end is spiral in its natural state, and an arc-shaped end tube 3 is installed at the annular distal end according to the shape of the annular distal end. The end tube 3 is preferably supported by a highly elastic polyurethane material. Multiple electrode pairs 2 are installed on the end 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 consists of two electrodes. For example, the first electrode pair closest to the tip (damage-preventing tip 8) consists of an annular electrode 11 and an annular electrode 12. 【0050】 Simply put, the ablation catheter according to the present invention has an annular distal end 1. The annular distal end 1 includes an arc-shaped terminal tube 3. The novel aspect of the present invention is that multiple electrode pairs are arranged at intervals along the arc-shaped extension direction of the terminal tube. These multiple electrode pairs 2 each surround the terminal tube 3. 【0051】 Figure 2 also shows the end rigid tube 4 and the positioning electrode 41 placed on it, which will be described later. 【0052】 As can be seen by combining Figures 1 and 2, one end of the terminal tube 3 is a free end and 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 terminal tube 3 is a fixed end. One end of the terminal rigid tube 4 is connected to the fixed end of the terminal tube 3. One end of the distal end tube 5 is connected to the other end of the terminal rigid tube 4. One end of the proximal end tube 6 is connected to the other end of the distal end tube 5. One end of the handle assembly 15 is connected to the other end of the proximal end tube 6. A push button 16 may be provided between the handle assembly 15 and the proximal end tube 6. A knob 17 may be provided on the handle assembly 15. Connectors 18 and 19 are connected to the other end of the handle assembly 15. 【0053】 Figure 3 is a schematic diagram of the arrangement of electrode pairs in the natural state of the distal annular end. As shown in Figure 3, for example, the first electrode pair 111 consists of two fine annular electrodes. The annular electrodes are preferably gold or platinum electrodes, and the dimensions (which can be called "length" or "width") in the arc-extending direction of the terminal tube are 0.50 to 1.5 millimeters. The clearance distance between the annular electrodes is 1 to 3 millimeters. The clearance distance between the pairs of annular electrodes is 3 to 6 millimeters. It should be noted that the initial design considerations for the electrode width, spacing, etc., adopted here are based on the fact that the diameter of the distal annular end is contractible, and therefore the electrode dimensions must be adapted accordingly. In particular, the dimensions of the electrodes in the arc-extending direction of the terminal tube, the so-called "length" or "width," must be appropriate. If the dimensions are too large, it will affect the contraction effect of the distal annular end, so the two annular electrodes should be arranged to form a pair of electrodes. 【0054】 In short, each electrode pair 2 includes two annular electrodes surrounding the end tube 3, for example, annular electrode 11 and annular electrode 12, and the width of the end tube in the arc-shaped extension direction of each annular electrode, the distance between the two annular electrodes in the same electrode pair, and the distance between adjacent electrode pairs must be set to appropriate dimensions. In a preferred embodiment, there is a certain constraint relationship between these dimensions and the diameter of each annular electrode (explained in detail below). 【0055】 In this disclosure, terms such as “dimension in the arcuate extension direction of the terminal tube” and “spacing” are used to describe the annular or arcuate perimeter of the distal annular end that is in contact with the myocardial tissue to be ablated, and not the diameter of the terminal tube or the distal annular end. Those skilled in the art will understand that such dimensions may be described as either “length” or “width,” and by default, neither “length” nor “width” refers to the annular perimeter and not the diameter of the tube. 【0056】 As mentioned above, 2N+1 (odd number) annular electrode pairs may be provided at the distal annular end. As shown in Figure 3, during discharge ablation, voltages are applied alternately to the first to ninth electrode pairs 111-119. For example, the positive electrode is applied to the first electrode pair 111, and the negative electrode to the second electrode pair 112, and so on, meaning that the polarity of adjacent electrode pairs is reversed. The last electrode pair in Figure 3 is the ninth electrode pair 119, which has a positive polarity. Since the number of electrode pairs is odd, 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 this arrangement is to ensure that even if the electrodes overlap when the distal annular end contracts, arc problems will not occur, thereby guaranteeing safety during use. In ablation mode, two electrodes in an electrode pair have the same polarity during discharge ablation and can be considered equivalent to a single electrode. The design of a separate electrode pair (consisting of two annular electrodes) can reduce the rigidity of the terminal tube and facilitate the contraction of the annular distal end dimensions. 【0057】 As shown in Figure 13, the annular electrode may also be a helical electrode. A helical electrode is an electrode formed by winding electrode lead wires or cutting an annular electrode into a helical shape. 【0058】 Returning to Figure 3, when the annular electrodes are placed in the terminal tube 3, the rigidity of the terminal tube can be reduced, facilitating the contraction of the annular distal end diameter. Electrode pairs 111-119 are all annular, preferably in an equally spaced configuration, surrounding the terminal tube 3. The terminal tube 3 is connected to the terminal rigid tube 4. The electrode material is platinum-iridium alloy or gold. 【0059】 In a preferred embodiment of the present invention, the ablation catheter is a pulsed electric field ablation catheter, which is used to transmit and release pulsed ablation energy to the site where ablation is to be performed. 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 according to the present invention can be used for ablation of the heart and surrounding tissues. 【0060】 Pulsed electric field ablation involves applying a high voltage between electrodes to perform discharge ablation, with the voltage being between 1000 and 4000V. Therefore, the electrode surface area must be sufficiently large; otherwise, the local electric field strength will be too concentrated during discharge, causing arcing. However, as mentioned above, the issue of adjustable distal annular end diameter must be considered, and for this reason, the electrodes are arranged as electrode pairs. A single electrode is placed at a certain relatively short distance interval, after which another electrode is placed. This allows the two electrodes to form an electrode pair, and during discharge, the pair of electrodes (electrode pair) can be treated as equivalent to a single electrode, thus allowing the discharge action of an electrode with a sufficiently large surface area to be exerted. At the same time, the large size of the electrodes does not affect the adjustment of the distal annular end diameter. 【0061】 On the other hand, the distance between the two electrodes in an electrode pair is relatively close, allowing each electrode to be used for measurement independently at the same time. Because the pulsed electric field energy output is relatively high and concentrated, the distance between the positive and negative electrodes to which high voltage is applied is required to be as large as possible. However, if the electrode spacing is too large, the range of the electrophysiological signal collected becomes too broad, affecting the assessment of the local ablation effect. Therefore, after ablation is complete, collecting the electrophysiological signal using two electrodes in the electrode pair that are relatively close together allows for a more accurate assessment of the electrophysiological signal. This enables a more detailed assessment of the local electrical signal. Avoiding excessively large electrode spacing prevents the introduction of a wide range of electrophysiological signals that could affect the assessment of the ablation effect. 【0062】 Therefore, simply put, when used in pulsed field ablation, the ablation catheter is in ablation mode, and the polarity of the two electrodes in each electrode pair is the same. This is equivalent to applying a voltage to a single electrode, and thus, during ablation, it acts as a discharge of a single electrode with a sufficiently large surface area. At the same time, 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 exert their own effects, that is, they are used to collect electrophysiological signals independently, performing the function of two electrodes that are relatively close together. 【0064】 Figure 4 is a schematic diagram of the traction assembly arrangement of the distal end tube. As shown in Figure 4, the annular distal end 1 is positioned in the terminal rigid tube 4. The terminal tube 3 connects to the terminal rigid tube 4 in a portion that is not bent near the proximal end. The traction assembly 42 is positioned inside the terminal rigid tube 4. The traction assembly 42 is fixed to the terminal rigid tube 4. Bending of the distal end tube 5 (see Figure 14) can be achieved under the control of a push button 16 between the handle assembly 15 and the proximal end tube 6. A positioning electrode 41 is installed in the terminal rigid tube 4 and used to align with the positioning of positioning sensors (for example, positioning sensors 131, 132, 133 described later). 【0065】 Figure 5 is a schematic diagram of the contracted state of the distal annular end. Figure 6 is a schematic diagram of the arrangement of the electrode pair in the contracted state of the distal annular end. Figure 10 is a schematic side view of the tensile state of the distal annular end. Figure 15 is an internal schematic diagram of the contraction control assembly of the distal annular end. 【0066】 As mentioned above, the handle assembly 15 may have a knob 17. By rotating the knob 17, the contraction and recovery of the retractable rope can be controlled, thereby changing the annular diameter of the distal annular end. 【0067】 Referring to Figures 5, 6, 10, and 15, and more specifically as shown in Figure 15, when the knob 17 on the handle assembly 15 is operated, the slide block 171 moves by moving the retractable rope 9. The retractable rope 9 is fixed to the slide block 171. A female thread is provided inside the rotating core shaft 172, which engages with a male thread on the slide block 171. When the knob 17 is rotated clockwise, the knob 17 drives the rotating core shaft 172 to rotate, which moves the slide block 171 backward, pulls the retractable rope 9, and further retracts the annular distal end 1. When the knob 17 is rotated counterclockwise, the retractable rope 9 recovers, and the diameter of the annular distal end 1 increases or recovers. 【0068】 As mentioned above, in its natural state, the distal annular end exhibits a spiral annular shape, with an annular diameter of 20-35 millimeters. The tip and end of the distal annular end 1 are separated, and the distance of this separation is 1 / 5 to 1 / 4 of the annular circumference. As shown in Figures 5, 6, and 10, when the distal annular end 1 is contracted to its minimum extent, there is no overlap between the two electrode pairs 111 and 119 at the tip and end of the terminal tube 3, further increasing safety. When the diameter of the distal annular end is contracted to its minimum extent, the distal annular end 1 exhibits a closed annular shape in its annular cross-section, with an annular diameter of 12-15 millimeters, and there is no overlap between the electrode pairs at the tip and end. Figures 5 and 10 show the terminal rigid tube 4 or a part thereof, in addition to the terminal tube 3 and electrode pairs (e.g., 111 and 119). 【0069】 The ablation catheter according to the present invention further includes a support member positioned to penetrate the terminal tubular body and the inside of the terminal rigid tube, and a retractable rope installed on the annular inner side of the support member. One end of the retractable rope is fixed to the injury prevention tip together with one end of the support member. When the retractable rope is retracted, it pulls and deforms the support member, adjusting the annular diameter of the distal annular end. 【0070】 A schematic diagram of the support member is shown in Figure 7. The support member 7 is annular in shape. The shape of the distal annular end is mainly determined by the shape of the support member. The material of the support member is a highly elastic memory alloy, such as nickel-titanium alloy (NiTi), which can instantly recover its original shape after external forces are removed. In a preferred embodiment, the diameters of the support member tip 71 and the support member proximal end 72 do not coincide. To achieve the function of adjustable diameter of the distal annular 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. To achieve contraction of the distal annular end 1, the distal annular end 1 contracts under the action of the contraction rope 9, but if the tip rigidity is too high, tip deformation and contraction cannot be achieved. For this reason, 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 shrinkable rope 9 is preferably a flexible stainless steel wire rope with relatively high tensile strength, and its diameter is 0.10 to 0.15 millimeters. The flexible shrinkable rope 9 avoids causing an increase in the rigidity of the annular distal end 1 and also avoids affecting the normal deformation of the ring. The shrinkable rope 9 may also be a polyethylene rope (PE rope), which is soft and has higher tensile strength. The shrinkable rope 9 will be described in more detail below. 【0071】 Figure 8 is a schematic internal view of the distal annular end. Figure 9 is a schematic arrangement of positioning sensors within the distal annular end. Figure 11 is a schematic cross-sectional view of the tip of the distal annular end. 【0072】 As shown in Figure 8, a shrinkable rope 9 is provided on the annular inner side of the support member 7, and the support member 7 can be deformed by the shrinkable 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 reduced. Both the support member 7 and the shrinkable rope 9 are fixed within the damage prevention end 8 at the tip of the annular distal end 1. As shown in Figure 11, the outside of the support member 7 and the shrinkable rope 9 is covered by a protective tube 10. The protective tube 10 protects the internal components of the end tube 3 from being affected when the shrinkable rope 9 shrinks, and at the same time makes the shrinkage of the shrinkable rope 9 smoother. The material of the protective tube 10 is preferably polytetrafluoroethylene tubing. 【0073】 In a preferred embodiment of the present invention, the positioning sensor may be located below the electrode pair such that the positioning sensor is located inside the end tube. 【0074】 As shown in Figure 9, the first positioning sensor 131 is located at the tip of the annular distal end 1, below the first electrode pair 111. The second positioning sensor 132 is located at an intermediate position of the annular distal end 1, for example, below the electrode pair at the intermediate position of the annular distal end 1, for example, below the sixth electrode pair 116. The third positioning sensor 133 is located inside the end rigid tube 4. These positioning sensors, together with the positioning electrodes 41 (Figures 2 and 4) and the electrodes on the end tube 3, can display the shape of the annular distal end 1 and the positional relationship of the electrodes, making it easier to observe whether or not there is overlap between the electrodes and better ensuring the safety of the electrodes. The magnetic positioning function allows monitoring of the position where overlap is most likely to occur, thereby limiting energy output under extreme conditions. The dimension of the end tube of the positioning sensor in the arc-extension direction (e.g., called "length") is equal to the sum of the dimensions of each of the two annular electrodes ("length" or "width" in the arc-extension direction of the end tube) and the distance between them, i.e., the dimension of one electrode pair (the width of the end tube of one electrode pair in the arc-extension direction), and is positioned directly below the electrode pair. This design is to avoid increasing the rigidity of the annular part. The positioning sensor has a cylindrical structure with a hollow center. This allows the support member 7 to pass through the center of the cylindrical structure and to fix the positioning sensor to the support member 7. The positioning sensor is a cylindrical structure with a spiral winding of copper lead wires, which itself has a certain elasticity, and after being protected and fixed with an outer highly elastic polyurethane material, it forms a positioning sensor that can be freely deformed without affecting performance, making it suitable for use in an adjustable annular ring. 【0075】 As shown in Figure 11, the positioning sensors are each fixed to the support member 7. The first positioning sensor 131 and the protective tube 10 (including the support member 7 and retractable rope 9 inside the protective tube 10) are fixed to the protective tube 14 for stable attachment. Similarly, the second positioning sensor 132 and the protective tube 10 may be fixed to the protective tube 14. The material of the protective tube 14 is preferably a highly elastic polyurethane pipe material that is highly elastic and easy to bond. The support member 7, retractable rope 9 and protective tube 10 are fixed to the damage prevention tip 8. In the schematic of Figure 11, the positioning sensor 131 is located at the tip of the annular distal end 1, below the pair of annular electrodes 11 and 12. The dimension of the end tube of the positioning sensor 131 in the arc-shaped extension direction (for example, called the "length") is equal to the dimensions of the two annular electrodes 11 and 12 (the "length" or "width" of the end tube in the arc-shaped extension direction) and the distance between them, i.e., the dimensions of one electrode pair, and is positioned directly below this pair of annular electrodes 11 and 12. 【0076】 As shown in Figure 11, the first positioning sensor 131 is fixed to the outer circumference of the protective tube 10. Since the first positioning sensor 131 has a hollow cylindrical structure, the protective tube 10 can pass through the center of the cylindrical structure of the first positioning sensor 131. That is, the support member 7 passes through the center of the cylindrical structure of the first positioning sensor 131. 【0077】 Similarly, the second positioning sensor 132 may be fixed to the outer circumference of the protective tube 10. Since the second positioning sensor 132 has a cylindrical structure and a hollow center, the protective tube 10 can pass through the center of the cylindrical structure of the second positioning sensor 132. That is, the support member 7 passes through the center of the cylindrical structure of the second positioning sensor 132. 【0078】 Figure 12 is a schematic cross-sectional view of the distal end tube. Figure 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 positioned 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 positioned within 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 of the traction assembly 42 can be controlled, thereby achieving bending of the distal end tube 5. 【0080】 As shown in Figures 12 and 14, pressing the push button 16 allows control of the bending of the distal end tube 5, helping the annular distal end 1 reach the desired position. As shown in Figure 12, the distal end tube 5 has a multi-cavity tube structure, and the contraction rope 9 of the annular distal end 1 is located in the intermediate cavity. Because it is located in the intermediate cavity, when the contraction rope 9 contracts, it does not affect the curvature of the distal end tube 5, nor does it pull on the bending of the distal end tube 5. The traction assembly 42 is located on the side of the distal end tube 5 to facilitate the bending of the distal end tube 5 without affecting the intermediate contraction rope 9. The contraction rope 9 is in the middle, and whether the distal end tube 5 is bent or stretched, it does not cause relative movement of the contraction rope 9. This avoids the problem that the contraction of the annular distal end 1 and the bending of the distal end tube 5 may interfere with each other. 【0081】 Figure 14 shows the same components and elements as in Figure 1, namely the push button 16 and knob 17, as well as the annular distal end 1, terminal rigid tube 4, distal end tube body 5, proximal end tube body 6, handle assembly 15, connector 18 and connector 19. Those skilled in the art will understand that the above-described components and elements are combined to form one preferred embodiment of the ablation catheter according to the present invention, but that the ablation catheter according to the present invention is not limited to including all of these components and elements. 【0082】 Furthermore, as mentioned above, the ablation catheter connector shown in Figures 1 and 14 includes at least two types of connectors: a connector 18 for transmitting positioning information between the catheter and the device, and a 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 annular electrodes on each electrode pair 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 measurement mode. 【0083】 Application Embodiments The specific use of the annular, distal-diameter variable ablation catheter of the present invention, according to applied embodiments, will be 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 embodiments shown in Figures 16 and 17 may include the following operation steps. Step 1: As shown in Figure 16, the diameter of the annular distal end 1 is reduced to that of the annular distal end 1 with a smaller diameter, and then inserted into the lumen structure 20. Step two: Electrophysiological signals are measured within the cavity structure 20, and a physical model of the cavity structure 20 is constructed. Step three: As shown in Figure 17, control the increase in diameter of the annular distal end 1 to ensure that the electrode makes good contact with the lumen structure 20. Step four: Discharge ablation is performed, with a voltage amplitude of 1000-4000V. After ablation, electrophysiological signals are collected by the two electrodes within the electrode pair. The immediate ablation effect can be determined by comparing the changes in the electrophysiological signals until the electrical activity of the lumen structure 20 is completely isolated. 【0085】 Figure 18 is a schematic diagram of the electric field distribution when electric field energy is released by the ablation catheter of the present invention. 【0086】 As shown in Figure 18, when pulsed discharge is performed, all electrodes on the ablation catheter form a continuous ablation region in the myocardial tissue 21, i.e., an electric field region 22 due to the discharge shown in the figure. Generally, the myocardial ablation effectiveness threshold is 400 V / CM. In the electric field region 22, the voltage intensity is greater than 400 V / CM, reaching this threshold, and effective myocardial ablation can be performed in this continuous region. The number of electrode pairs is 2N+1 (where N is a positive integer). Each electrode pair consists of two annular electrodes, and as shown in Figure 18, there are 9 electrode pairs. Both the first electrode pair 111 and the ninth electrode pair 119 consist of two fine annular electrodes. The annular electrodes are preferably gold or platinum electrodes, and their dimensions (length or width in the arc extension direction of the terminal tube) are 0.50 to 1.5 millimeters. The clearance distance between the ring electrodes is 1 to 3 millimeters, and the clearance distance between the ring electrode pairs is 3 to 6 millimeters. The applied pulse electric field width is 1000 to 4000 V. To improve ablation efficiency, a continuous ablation region is formed when the electrodes discharge, preventing ablation leakage points. Based on the electric field distribution and mechanical design of the electrodes, and assuming that the surface area of ​​the electrode pairs is sufficiently large and the spacing between the electrode pairs is appropriate, a continuous ablation region is formed during discharge ablation, and the annular adjustable function is ensured, with the following relationships: 【0087】 [Mathematics 1] (2×L+d)×k=D and S>D 【0088】 Here, L is the width (sometimes called "length") of the end tube arc of the annular electrode in the direction of extension, d is the distance between two annular electrodes in one electrode pair, D is the distance between adjacent electrode pairs, S is the diameter of each annular electrode, and k is a correction factor with a value between 0.7 and 1.4 (k = 0.7 to 1.4). As described above, in the preferred embodiment, L has a value of 0.50 to 1.5 millimeters, d has a value of 1 to 3 millimeters, and D has a value of 3 to 6 millimeters. 【0089】 While various elements and components of an ablation catheter have been mentioned in the various embodiments described above, those skilled in the art will understand that, unless explicitly excluded in the specification or not permitted or achievable in practice, these elements and components can be arbitrarily combined within an ablation catheter to exert their respective effects and achieve the appropriate function. None of the embodiments or examples described above limit the scope of the present invention. 【0090】 Electrode function control method The ablation catheter of the present invention can be used in both ablation mode and measurement mode, allowing for appropriate control of the electrodes and electrode pairs of the ablation catheter, enabling them to 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 surrounding tissues. According to the method proposed by the present invention, in the ablation mode of the catheter, electric field energy with the same polarity is transmitted to two electrodes in each electrode pair that are relatively close together, and the two electrodes in the electrode pair are treated as equivalent to a single electrode with a relatively large size or surface area, and a voltage is applied to the corresponding tissue, transmitting electric field energy with opposite polarity to adjacent electrode pairs, thereby realizing a pulsed electric field ablation function. On the other hand, in the measurement mode of the catheter, the two electrodes in each electrode pair that are relatively close together are used individually, that is, electrophysiological signals are collected independently by the two electrodes in each electrode pair, thereby realizing an electrophysiological measurement function. 【0092】 Computer programs or computer program products and computer-readable media Furthermore, those skilled in the art should recognize that the methods described herein can be implemented as computer programs. These methods are executed by one or more programs that include instructions for executing algorithms corresponding to a computer or processor. These programs can be provided to a computer or processor by being stored on various non-temporary computer-readable media. Non-temporary computer-readable media include various tangible storage media. Examples of non-temporary computer-readable media include magnetic recording media (such as floppy disks, tapes, and hard drives), magneto-optical recording media (such as magneto-optical disks), CD-ROMs (Compact Disk Read-Only Memory), CD-Rs, CD-R / Ws, and semiconductor memory (such as ROMs, PROMs (Programmable ROMs), EPROMs (Rewritable PROMs), Flash ROMs, and RAMs (Random Access Memory)). Moreover, 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. Temporary computer-readable media can be used to provide programs to a computer via wired communication paths such as wires and optical fibers, or via wireless communication paths. 【0093】 For example, according to one embodiment of the present disclosure, a computer-readable medium stores instructions that can be executed by a processor, and when such instructions are executed by the processor, the processor performs a method for controlling the function of the electrode pair on the ablation catheter. 【0094】 According to the contents of this disclosure, a computer program or computer program product may also be proposed that implements a method for controlling the function of the electrode pair on the ablation catheter when the computer program is executed. 【0095】 Furthermore, the present invention also relates to a computing device or computing system comprising a processor and memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, a method for controlling the function of an electrode pair on an ablation catheter is realized. 【0096】 Beneficial effects In summary, the ablation catheter according to the present invention has at least the following beneficial effects. 1. The design of a pulse catheter with an adjustable annular distal end is applicable to various lumen structures, and the adjustable mechanism is advantageous for the electrode on the annular distal end to better adhere to the tissue structure. 2. The design of the electrode pair is more convenient for adjusting the annular distal end diameter, while ensuring the effectiveness and safety of ablation. At the same time, the electrode pair is used to more accurately collect electrophysiological signals and avoid situations where the electrode spacing is too large and affects the interpretation of changes in electrical signals. 3. The electrode design of the above invention integrates the electrode pair into a single electrode during ablation and separates the electrode pair into two electrodes for measurement, thereby achieving a good balance between the effectiveness of pulsed field ablation and the accuracy of electrophysiological measurements. 4. We propose a positioning sensor installation method that can be freely deformed and does not affect performance. By applying this to the annular portion of the catheter whose diameter can be adjusted, it is possible to provide real-time display of the shape and electrode spacing during the operation of the ablation catheter, guiding the surgeon to precise ablation procedures, and simultaneously increasing safety by monitoring the electrode spacing. 5. High-pressure pulsed energy can be applied precisely and effectively to the target tissue, significantly reducing surgical time. High-pressure pulsed energy can selectively ablate the target tissue, reducing complications. 6. The catheter has measurement, modeling, and ablation functions, saving surgical time and costs. 【0097】 The embodiments of the present invention are not limited to those described above, and those skilled in the art can make various changes and improvements to the forms and details of the present invention without departing from the spirit and scope of the invention, all of which will be deemed to fall within the scope of the 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-Support Member 71-Support member tip 72-Proximal end of support member 8- Damage prevention tip 9- Contraction Rope 10-Protection tube 11-Annular electrode 12-Annular electrode 131-First positioning sensor 132 - Second positioning sensor 133 - Third positioning sensor 14-Sheathed Tube 15-Handle Assembly 16-Push Buttons 17-Knob 171-Slide Block 172-Rotating Core Axis 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 - Fifth electrode pair 116 - Sixth Electrode Pair 117 - Seventh electrode pair 118 - Eighth electrode pair 119 - Ninth Electrode Pair 21. Myocardial tissue 22. Electric field region formed by discharge

Claims

[Claim 1] Ablation catheter, It has an annular distal end (1), and the annular distal end (1) includes an arc-shaped terminal tube (3), Multiple electrode pairs (2) are arranged at intervals along the arc-shaped extension direction of the terminal tube, and each of the multiple electrode pairs (2) surrounds the terminal tube (3). Each electrode pair (2) includes two annular electrodes (11, 12) surrounding a terminal tube (3), the width of the terminal tube of each annular electrode in the arc-shaped extension direction is L, the distance between the two annular electrodes in one electrode pair is d, the distance between adjacent electrode pairs is D, the diameter of each annular electrode is S, and the following conditions are met: [Mathematics 1] S>D=(2×L+d)×k, Here, k is a correction factor, and k is a value between 0.7 and 1.

4. The catheter is a pulsed electric field ablation catheter, and is used to transmit and release pulsed ablation energy to the site where ablation is planned. In the case of pulsed field ablation, the polarity of two electrodes in each electrode pair is the same, which is equivalent to applying a voltage to one electrode, while the polarity of adjacent electrode pairs is opposite. For electrophysiological measurements, two electrodes in each electrode pair are used independently to collect electrophysiological signals. Inside the terminal tube (3), below the electrode pair (2), positioning sensors (131, 132) are arranged. The positioning sensor includes a first positioning sensor (131) and a second positioning sensor (132), wherein the first positioning sensor (131) is positioned below the first electrode pair from the tip of the distal annular end, and the second positioning sensor (132) is positioned below the electrode pair at an intermediate position of the distal annular end. One end of the terminal tube (3) is a free end, 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, A rigid end pipe (4) is connected at one end to the fixed end of the end pipe body (3), The distal end tube body (5) has one end connected to the other end of the terminal rigid tube (4), One end of the proximal end tube (6) is connected to the other end of the distal end tube (5), A handle assembly (15) having one end connected to the other end of the proximal end tube (6), The handle assembly (15) includes connectors (18, 19) connected to the other end, The system further includes a support member (7) made of memory alloy material, which is positioned to penetrate the interior of the end tube (3) and the end rigid tube (4), The retractable rope (9) is positioned inside the annular part of the support member (7), and one end of it is fixed to the damage prevention tip (8) together with the other end of the support member (7). Here, when the retractable rope (9) retracts, it pulls and deforms the support member (7), adjusting the diameter of the annular distal end (1). The catheter further includes a protective tube (10) that encloses the outside of the support member (7) and the retractable rope (9), An ablation catheter characterized in that positioning sensors (131, 132) are fixed to the outer circumference of the protective tube (10), the positioning sensors (131, 132) have a cylindrical structure, and the protective tube penetrates the center of the cylindrical structure. [Claim 2] The catheter according to claim 1, characterized in that the number of electrode pairs (2) is 2N+1, where N is a positive integer. [Claim 3] The catheter according to claim 1, characterized in that L is a value of 0.50 to 1.5 millimeters, d is a value of 1 to 3 millimeters, and D is a value of 3 to 6 millimeters. [Claim 4] The catheter according to claim 1, characterized in that the annular electrode is a helical electrode. [Claim 5] The catheter according to claim 4, characterized in that the helical electrode is formed by winding an electrode lead wire. [Claim 6] The catheter according to claim 4, characterized in that the helical electrode is an electrode made by cutting an annular electrode into a helical shape. [Claim 7] The catheter according to claim 1, characterized in that the catheter is for ablation of the heart and surrounding tissues. [Claim 8] The catheter according to claim 1, characterized in that the amplitude of the voltage applied to each electrode pair is 1000 to 4000 V. [Claim 9] The catheter according to claim 1, characterized in that the length of the terminal tubes of the positioning sensors (131, 132) in the arc-shaped extension direction is equal to the width of the terminal tubes of the electrode pair (2) in the arc-shaped extension direction. [Claim 10] The catheter according to claim 9, characterized in that the length of the terminal tubes of the positioning sensors (131, 132) in the arc-shaped extension direction is equal to the sum of the width and the distance between them in the arc-shaped extension direction of each terminal tube of the two annular electrodes in the electrode pair. [Claim 11] The catheter according to claim 1, characterized in that the annular diameter of the distal annular end is retractable. [Claim 12] The catheter according to claim 11, characterized in that the annular distal end is spiral in its natural state, has an annular diameter of 20 to 35 millimeters, and is separated from the tip to the end of the annular distal end, with the separation distance being 1 / 5 to 1 / 4 of the annular circumference. [Claim 13] The catheter according to claim 12, characterized in that when the distal annular end is contracted to its minimum extent, the annular diameter is 12 to 15 millimeters, the distal annular end exhibits a closed ring in its annular cross-section, and the electrode pairs on the tip and end of the distal annular end do not overlap. [Claim 14] The catheter according to claim 1, wherein the handle assembly (15) has a knob (17) which is set to control the contraction and recovery of the retractable rope (9) by rotation. [Claim 15] The catheter according to claim 1, characterized in that the positioning sensors (131, 132) and the protective tube (10) are fixed by a sheath tube (14). [Claim 16] The catheter further includes the following: The catheter according to claim 1, wherein a push button (16) is disposed between the handle assembly (15) and the proximal end tube (6), the push button (15) is connected to one end of a traction assembly (42) disposed within the distal end tube (5), the other end of the traction assembly (42) is connected to the terminal rigid tube (4), and the bending of the distal end tube (5) is achieved by pressing the push button (16) to control the tightening or loosening of the traction assembly (42). [Claim 17] The catheter according to claim 16, characterized in that the traction assembly (42) is positioned on the side of the distal end tube (5). [Claim 18] The catheter according to claim 1, characterized in that a positioning electrode (41) is placed on the terminal rigid tube (4), and a third positioning sensor (133) is placed inside the terminal rigid tube (4). [Claim 19] The aforementioned connectors (18, 19) A first connector (18) is connected to positioning sensors (131, 132, 133) via a first cable and configured to transmit positioning information, The catheter according to claim 1, further comprising a second connector (19) configured to transmit ablation energy, which is connected via a second cable to annular electrodes on each electrode pair.

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