Pulsed electric field ablation catheter and cooling method

Abstract

The present application is applicable to the technical field of pulsed electric field ablation catheters, and provides a pulsed electric field ablation catheter. The pulsed electric field ablation catheter comprises: a tube body part and an expansion part. The tube body part comprises a main body tube and a push-pull tube, and the push-pull tube movably penetrates through the main body tube and at least partially extends out from a distal end of the main body tube. The expansion part comprises an expansion tube, and a plurality of branch tubes are formed between a proximal end and a distal end of the expansion tube. At least one treatment electrode is provided on the branch tube, and a cooling gap in communication with the external environment is provided between the branch tube and the treatment electrode. A first perfusion channel is provided on the main body tube, and a second perfusion channel is provided on the branch tube. The first perfusion channel is in communication with the second perfusion channel, and the second perfusion channel is in communication with the cooling gap. The pulsed electric field ablation catheter provided by the present application does not require a perfusion hole to be formed on the surface of the treatment electrode, which can effectively avoid the phenomenon of spark discharge on the treatment electrode, offering high reliability.

Description

Pulsed electric field ablation catheter and cooling method

[0001] Cross-reference of related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 202410705660.3, filed on May 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of medical device technology, and in particular relates to a pulsed electric field ablation catheter and a cooling method. Background Technology

[0004] The pulsed electric field ablation catheter is a medical device used for cardiac electrophysiological ablation surgery. Its working principle is to use the non-thermal effect of irreversible electroporation (IRE) to release high-voltage pulse energy in the heart chamber through the catheter electrode, causing irreversible electroporation of the myocardial cell membrane, which leads to the gradual necrosis of the myocardial cells, thereby blocking the propagation of abnormal electrical signals and achieving the purpose of treating arrhythmia. Summary of the Invention

[0005] In some embodiments, this application provides a pulsed electric field ablation catheter, comprising: a tube body and an expansion portion, wherein the tube body includes a main tube and a push-pull tube, the push-pull tube being movably inserted within the main tube and extending at least partially from the distal end of the main tube; the expansion portion includes an expansion tube, with multiple branch tubes formed between the proximal and distal ends of the expansion tube, the multiple branch tubes being spaced apart circumferentially along the expansion tube, the proximal end of the expansion tube being connected to the distal end of the main tube, and the distal end of the expansion tube being connected to the distal end of the push-pull tube; at least one treatment electrode is disposed on the branch tube, a cooling gap communicating with the external environment is provided between the branch tube and the treatment electrode, a first infusion channel is disposed on the main tube, a second infusion channel is disposed on the branch tube, the first infusion channel and the second infusion channel are communicating, and the second infusion channel is communicating with the cooling gap.

[0006] In some embodiments, this application provides a cooling method applied to a pulsed electric field ablation catheter, the pulsed electric field ablation catheter comprising a tube body and an expansion portion; the tube body includes a main tube and a push-pull tube, the push-pull tube being movably inserted within the main tube and extending at least partially from the distal end of the main tube; the expansion portion includes an expansion tube, with multiple branch tubes formed between the proximal and distal ends of the expansion tube, the proximal end of the expansion tube being connected to the distal end of the main tube, and the distal end of the expansion tube being connected to the distal end of the push-pull tube; at least one treatment electrode is disposed on each branch tube, and a cooling gap communicating with the external environment is formed between the branch tube and the treatment electrode; a first infusion channel is disposed on the main tube, and a second infusion channel is disposed on each branch tube, the first infusion channel communicating with the second infusion channel, and the second infusion channel communicating with the cooling gap; the method includes: receiving infusion fluid through the first infusion channel; transporting the infusion fluid from the first infusion channel to the second infusion channel; and transporting the infusion fluid from the second infusion channel to the cooling gap. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 is a schematic diagram of the structure of the pulsed electric field ablation catheter provided in at least one embodiment of this application;

[0009] Figure 2 is a partial cross-sectional schematic diagram of the pulsed electric field ablation catheter provided in at least one embodiment of this application;

[0010] Figure 3 is a partial cross-sectional schematic diagram of a pulsed electric field ablation catheter at another location provided in at least one embodiment of this application;

[0011] Figure 4 is a partial cross-sectional schematic diagram of a pulsed electric field ablation catheter at another location provided in at least one embodiment of this application;

[0012] Figure 5 is a partial working schematic diagram of a pulsed electric field ablation catheter without cold saline perfusion of the treatment electrode provided in at least one embodiment of this application;

[0013] Figure 6 is a partial working schematic diagram of a pulsed electric field ablation catheter for perfusing cold saline to a therapeutic electrode, provided in at least one embodiment of this application;

[0014] Figure 7 is a partial cross-sectional schematic diagram of a pulsed electric field ablation catheter with its tip coated by cold saline, provided in at least one embodiment of this application;

[0015] Figure 8 is a flowchart of a cooling method provided in at least one embodiment of this application;

[0016] Figure 9 is a flowchart of another cooling method provided in at least one embodiment of this application;

[0017] The reference numerals in the above figures are detailed as follows: 101, proximal end; 102, distal end; 103, direction of water flow; 10, tube body; 11, main tube; 111, first infusion channel; 112, push-pull channel; 12, push-pull tube; 13, connecting tube; 20, expansion section; 21, expansion tube; 211, branch tube; 2111, second infusion channel; 2112, infusion hole; 212, treatment electrode; 22, first seal; 23, second seal; 30, cooling gap; 31, cooling recess; 40, shunt chamber; 50, power supply line; 60, blood; 70, mixed conductive solution; 80, cold saline; 90, tip. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0019] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly or indirectly on that other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to that other element. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] A pulsed electric field ablation catheter is a medical device used for cardiac electrophysiological ablation surgery. It works by delivering a high-intensity pulsed electric field to the heart tissue through the catheter, disrupting the conduction pathways of abnormal cardiac electrical signals, thereby treating diseases such as arrhythmias. A pulsed electric field ablation catheter typically consists of a catheter body, electrodes, and a pulse generator. During the procedure, the doctor inserts the catheter through a blood vessel into the heart, bringing the electrodes into contact with the area to be ablated. The pulse generator then activates, producing a pulsed electric field that causes irreversible electroporation and apoptosis of cells, achieving the ablation effect. During the use of the pulsed electric field ablation catheter, the electrodes release high-voltage pulse energy. Close spacing between the electrodes can cause spark discharges in the blood, creating localized high temperatures that may lead to thrombosis or scab formation. Therefore, real-time temperature control of the electrodes is necessary.

[0023] Current pulsed electric field ablation catheters typically control electrode temperature rise through cold saline irrigation. This requires creating irrigation channels in the catheter body and irrigation holes on the electrode surface to control the electrode tip temperature. However, creating irrigation holes on the electrode surface can lead to sharp point formation. When the electrode surface has sharp points, there is a risk of spark discharge near these points during operation, potentially causing localized high temperatures and leading to thrombosis or scab formation, thus affecting the effectiveness and safety of the procedure.

[0024] The term "electroporation" in this article refers to applying an electric field to the cell membrane to alter its permeability to the extracellular environment. The term "irreversible electroporation" in this article refers to applying an electric field to the cell membrane to permanently alter its permeability to the extracellular environment. For example, cells subjected to irreversible electroporation may show the formation of one or more pores in their cell membrane that persist even after the electric field is removed. The term "proximal" (labeled 101) in this article refers to the end of the pulsed electric field ablation catheter closest to the operator or connected to the procedure; "distal" (labeled 102) refers to the end of the pulsed electric field ablation catheter inserted into a blood vessel or close to the tissue to be treated.

[0025] Referring to Figures 1 to 7, in order to solve at least some of the above-mentioned problems, according to one aspect of this application, at least one embodiment of this application provides a pulsed electric field ablation catheter. The pulsed electric field ablation catheter includes a tube body 10 and an expansion portion 20, wherein the tube body 10 includes a main tube 11 and a push-pull tube 12, the push-pull tube 12 being movably inserted into the main tube 11 and extending at least partially from the distal end of the main tube 11. The expansion portion 20 includes an expansion tube 21, and a plurality of branch tubes 211 are formed between the proximal and distal ends of the expansion tube 21.

[0026] For example, multiple branch pipes 211 are arranged at circumferential intervals along the expansion pipe 21.

[0027] The proximal end of the expansion tube 21 is connected to the distal end of the main tube 11, and the distal end of the expansion tube 21 is connected to the distal end of the push-pull tube 12.

[0028] At least one treatment electrode 212 is provided on the branch pipe 211, and a cooling gap 30 communicating with the external environment is provided between the branch pipe 211 and the treatment electrode 212. A first infusion channel 111 is provided on the main pipe 11, and a second infusion channel 2111 is provided on the branch pipe 211. The first infusion channel 111 and the second infusion channel 2111 are connected, and the second infusion channel 2111 is connected with the cooling gap 30.

[0029] The pulsed electric field ablation catheter provided in at least one embodiment of this application movably inserts a push-pull tube 12 into the main tube body, with the push-pull tube 12 extending at least partially from the distal end of the main tube 11. Simultaneously, both ends of the expansion tube 21 are connected to the distal ends of the main tube 11 and the push-pull tube 12, respectively. This allows multiple branch tubes 211 located between the proximal and distal ends of the expansion tube 21 to deform radially along the expansion tube 21 as the push-pull tube 12 moves. By providing at least one treatment electrode 212 on each branch tube 211, the treatment electrode 212 can be positioned radially along the expansion tube 21 as the branch tube 211 deforms. Meanwhile, by setting a cooling gap 30 that communicates with the external environment between the branch pipe 211 and the treatment electrode 212, a first infusion channel 111 is set on the main pipe 11, and a second infusion channel 2111 is set on the branch pipe 211. The first infusion channel 111 and the second infusion channel 2111 are connected, and the second infusion channel 2111 is connected with the cooling gap 30. This allows the infusion liquid (such as cold saline 80) in the first infusion channel 111 to be infused into the cooling gap 30 between the branch pipe 211 and the treatment electrode 212 through the second infusion channel 2111 and to flow into the external environment, thereby achieving cooling and temperature reduction of the treatment electrode 212.

[0030] The pulsed electric field ablation catheter provided in at least one embodiment of this application does not require the opening of an infusion hole 2112 on the surface of the treatment electrode 212, thus helping to avoid the phenomenon of spark discharge on the treatment electrode 212 and having high reliability.

[0031] During the ablation of target tissue by the pulsed electric field ablation catheter provided in at least one embodiment of this application, the infusion liquid (such as cold saline 80) can be discharged through the cooling gap 30 to the vicinity of the treatment electrode 212 and mix with the blood near the treatment electrode 212, thereby reducing the treatment impedance of the treatment electrode 212. This allows the pulsed electric field generated on the treatment electrode 212 to act on the target tissue more easily. Furthermore, when the treatment electrode 212 has a tip 90, the cold saline 80 discharged from the cooling gap 30 to the vicinity of the treatment electrode 212 can also coat the tip 90 in the form of water droplets, thereby improving the uniformity of the electric field distribution on the end face and tip 90 of the treatment electrode 212 and preventing spark discharge caused by uneven electric field distribution of the treatment electrode 212.

[0032] Referring to Figure 1, in one exemplary embodiment, the number of branch pipes 211 is five. Of course, in other embodiments, the number of branch pipes 211 provided in this embodiment may also be other numbers.

[0033] Referring to Figure 3, in one exemplary embodiment, the expansion tube 21 is sleeved over the push-pull tube 12. The expansion part 20 also includes a first sealing member 22, which is disposed on the proximal end of the expansion tube 21 and located between the expansion tube 21 and the push-pull tube 12, for sealing the gap between the expansion tube 21 and the push-pull tube 12.

[0034] By sleeved the expansion tube 21 over the push-pull tube 12, multiple branch tubes 211 can be located radially outside the push-pull tube 12, causing the multiple branch tubes 211 to deform radially as the push-pull tube 12 moves. Simultaneously, by providing a first sealing element 22 at the proximal end of the expansion tube 21 and positioning it between the expansion tube 21 and the push-pull tube 12, the pulsed electric field ablation catheter can seal the gap between the expansion tube 21 and the push-pull tube 12 through the first sealing element 22. Referring to Figures 1 and 4, in an exemplary embodiment, the tube body 10 further includes a connecting tube 13, with both ends of the connecting tube 13 sleeved on the proximal end of the expansion tube 21 and the distal end of the main tube 11, respectively, for connecting the expansion tube 21 and the main tube 11. The expansion tube 21 and the main tube 11 can be connected by a connecting tube 13, for example, the two ends of the connecting tube 13 are fixed to the proximal end of the expansion tube 21 and the distal end of the main tube 11, respectively.

[0035] In an optional embodiment, the connecting tube 13 is a Pebax thin-walled tube, the distal inner wall of the Pebax thin-walled tube is fused to the proximal outer wall of the expansion tube 21, and the proximal inner wall of the Pebax thin-walled tube is fused to the distal outer wall of the main tube 11, so as to realize the connection and communication between the expansion tube 21 and the main tube 11.

[0036] Referring to Figure 4, in order to ensure that the cold saline solution in the first infusion channel 111 can be evenly infused into the multiple second infusion channels 2111, a diversion cavity 40 is formed between the proximal end of the expansion tube 21, the distal end of the main tube 11, and the inner wall of the connecting tube 13. The first infusion channel 111 and the second infusion channels 2111 can be connected through the diversion cavity 40. For example, there is a gap between the proximal end of the expansion tube 21 and the distal end of the main tube 11, thereby forming at least a portion of the diversion cavity 40. By providing the diversion cavity 40 between the proximal end of the expansion tube 21, the distal end of the main tube 11, and the inner wall of the connecting tube 13, the first infusion channel 111 can be simultaneously connected to the multiple second infusion channels 2111 through the diversion cavity 40, thereby ensuring that the cold saline solution in the first infusion channel 111 can be evenly infused into the multiple second infusion channels 2111.

[0037] Pulsed electric field ablation catheters typically have a large number of electrodes, each requiring a corresponding infusion channel for cooling. However, the diameter of the main tube 11 of the pulsed electric field ablation catheter is limited. The more infusion channels a catheter has, the smaller the inner diameter of each individual channel becomes, resulting in lower space utilization of the main tube 11 and limited flow of cold saline solution within the channels, potentially leading to poorer electrode cooling. In contrast, the pulsed electric field ablation catheter provided in at least one embodiment of this application features a single first infusion channel 111 on the main tube 11, connected to multiple second infusion channels 2111 via a shunt cavity 40. This eliminates the need for multiple corresponding infusion channels on the main tube 11, resulting in higher space utilization of the main tube 11 and effectively increasing the flow rate of cold saline solution in the pulsed electric field ablation catheter.

[0038] Referring to Figure 2, in one exemplary embodiment, the branch tube 211 is provided with an infusion port 2112, the position of which corresponds to the position of the treatment electrode 212, for connecting the second infusion channel 2111 and the cooling gap 30. By providing the infusion port 2112 on the branch tube 211 corresponding to the position of the treatment electrode 212, the pulsed electric field ablation catheter can connect the second infusion channel 2111 and the cooling gap 30 through the infusion port 2112.

[0039] Referring to Figure 2, in an exemplary embodiment, a cooling recess 31 is provided on the outer wall of the branch pipe 211. The position of the cooling recess 31 corresponds to the position of the treatment electrode 212, and a cooling gap 30 is formed between the cooling recess 31 and the treatment electrode 212. The two ends of the infusion hole 2112 are respectively connected to the cooling gap 30 formed on the cooling recess 31 and the second infusion channel 2111. Exemplarily, the infusion hole 2112 is formed in the wall of the branch pipe 211, penetrating the wall of the branch pipe 211, i.e., the length of the infusion hole 2112 is the length of the wall of the branch pipe 211, and the two ends of the infusion hole 2112 are respectively connected to the cooling recess and the second infusion channel 2111. By providing a cooling recess 31 on the outer wall of the branch pipe 211 and making the position of the cooling recess 31 correspond to the position of the treatment electrode 212, a cooling gap 30 can be formed between the cooling recess 31 and the treatment electrode 212.

[0040] Referring to Figures 1 and 2, in an exemplary embodiment, the treatment electrode 212 is a ring electrode, which is sleeved on the branch tube 211.

[0041] There are multiple cooling recesses 31 and multiple filling holes 2112. Multiple cooling recesses 31 are arranged at intervals along the circumference of the branch pipe 211, and multiple filling holes 2112 correspond one-to-one with multiple cooling recesses 31.

[0042] Multiple cooling recesses 31 and injection holes 2112 are provided, and multiple cooling recesses 31 are arranged at intervals along the circumference of branch pipe 211. Multiple injection holes 2112 correspond one-to-one with multiple cooling recesses 31, so that the electrode can be injected with cold brine through multiple cooling gaps 30, which effectively improves the cooling effect on the electrode.

[0043] In one optional embodiment, there are two cooling recesses 31 and two filling holes 2112. The two cooling recesses 31 are respectively disposed on both sides of the branch pipe 211 in the circumferential direction of the expansion pipe 21, and the two filling holes 2112 correspond to the two cooling recesses 31 respectively. In other words, the two cooling recesses 31 are respectively disposed on both sides of the branch pipe 211 along its own length direction, and the two cooling recesses 31 are distributed along the circumferential direction of the expansion pipe 21.

[0044] Referring to Figure 3, in one exemplary embodiment, the first sealing element 22 includes a sealing tube that passes through the expansion tube 21 and is sleeved on the push-pull tube 12. The outer wall of the sealing tube is fixedly connected to the inner wall of the expansion tube 21, and the inner wall of the sealing tube abuts against the outer wall of the push-pull tube 12. By having the sealing tube pass through the expansion tube 21 and be sleeved on the push-pull tube 12, and by fixing the outer wall of the sealing tube to the inner wall of the expansion tube 21 while abutting against the outer wall of the push-pull tube 12, the gap between the inner wall of the expansion tube 21 and the outer wall of the push-pull tube 12 can be effectively sealed by the sealing tube.

[0045] In one optional embodiment, the sealing tube is a TPU thin-walled tube, and the TPU thin-walled tube is fixedly connected to the inner wall of the expansion tube 21 by adhesive bonding.

[0046] In one optional embodiment, the TPU thin-walled tube and the push-pull tube 12 are interference-fitted. Since the TPU thin-walled tube has a certain elasticity, it can form a piston during the push-pull process of the push-pull tube 12. This helps to ensure the smooth push-pull of the push-pull tube 12 while sealing the gap between the inner wall of the expansion tube 21 and the outer wall of the push-pull tube 12 in real time.

[0047] Referring to Figure 1, in one exemplary embodiment, a plurality of treatment electrodes 212 are disposed on the branch tube 211, and the plurality of treatment electrodes 212 are spaced apart along the extension direction of the branch tube 211. By providing a plurality of treatment electrodes 212 on the branch tube 211 and arranging the plurality of treatment electrodes 212 spaced apart along the extension direction of the branch tube 211, the pulsed electric field ablation catheter can have a better therapeutic effect.

[0048] In one alternative embodiment, a plurality of treatment electrodes 212 are spaced apart in the middle of the branch tube 211.

[0049] In one optional embodiment, the distance between two adjacent treatment electrodes 212 is 1.5-3 mm, such as 2 mm. It is understood that the 2 mm description is for ease of understanding only, but can vary by ±0.5 mm.

[0050] In one alternative embodiment, the number of treatment electrodes 212 on a single branch tube 211 is two. Of course, in other embodiments, the number of treatment electrodes 212 on a single branch tube 211 may also be other numbers.

[0051] Referring to Figure 1, in an exemplary embodiment, to minimize the flow of cold saline solution from the distal end of the second infusion channel 2111 into the external environment, the expansion portion 20 further includes a second sealing member 23. The second sealing member 23 is disposed on the distal end of the expansion tube 21 to seal the distal end of the second infusion channel 2111. By providing the second sealing member 23 on the distal end of the expansion tube 21, the pulsed electric field ablation catheter can seal the distal end of the second infusion channel 2111 through the second sealing member 23. This helps prevent the cold saline solution from flowing into the external environment from the distal end of the second infusion channel 2111, and ensures that the cold saline solution can only flow out through the infusion hole 2112 from the cooling gap 30, thereby allowing the treatment electrode 212 to be sufficiently cooled.

[0052] Referring to Figure 2, in an optional embodiment, the pulsed electric field ablation catheter further includes a power supply line 50, which is at least partially inserted into the second infusion channel 2111 and electrically connected to the treatment electrode 212. An external pulse power supply device can supply power to the treatment electrode 212 through the power supply line 50.

[0053] In one alternative embodiment, the power supply line 50 is enameled wire.

[0054] In one optional embodiment, the main tube 11 is provided with a push-pull channel 112, and the push-pull tube 12 is movably inserted into the push-pull channel 112. The push-pull channel 112 is connected to the shunt cavity 40, and the pulsed electric field ablation catheter can perform cold saline perfusion into the shunt cavity 40 through the gap between the push-pull tube 12 and the push-pull channel 112.

[0055] Referring to Figure 5, in an exemplary embodiment, when the treatment electrode 212 is not cooled by infusion of cold saline 80, the pulsed electric field generated on the treatment electrode 212 needs to pass through the blood 60 to act on the target tissue, which may result in high impedance and poor treatment effect.

[0056] Referring to Figure 6, in an exemplary embodiment, when the pulsed electric field ablation catheter perfuses and cools the treatment electrode 212 through cold saline 80, the cold saline 80 is discharged into the vicinity of the treatment electrode 212 through the cooling gap 30, increasing the contact area between the treatment electrode 212 and the blood 60. Furthermore, the cold saline 80 has a certain degree of conductivity, and its impedance is generally lower than that of the blood 60. Therefore, the cold saline 80 can mix with the blood 60 near the treatment electrode 212 to form a mixed conductive solution 70, which may help reduce the treatment impedance of the treatment electrode 212, allowing the pulsed electric field generated on the treatment electrode 212 to more easily act on the target tissue, and thus improving the treatment effect of the treatment electrode 212.

[0057] In an exemplary embodiment, referring to FIG7, when the treatment electrode 212 has a tip 90, the pulsed electric field ablation catheter can cover the tip 90 in the form of water droplets by the cold saline 80 discharged from the cooling gap 30 to the vicinity of the treatment electrode 212. This is beneficial to improve the uniformity of the electric field distribution on the end face of the treatment electrode 212 and the tip 90, and to prevent spark discharge caused by uneven electric field distribution of the treatment electrode 212.

[0058] In one exemplary embodiment, the pulsed electric field ablation catheter has at least the following beneficial technical effects: By movably inserting a push-pull tube 12 into the main tube body, with the push-pull tube 12 extending at least partially from the distal end of the main tube 11, and simultaneously connecting both ends of the expansion tube 21 to the distal ends of the main tube 11 and the push-pull tube 12 respectively, multiple branch tubes 211 located between the proximal and distal ends of the expansion tube 21 can deform radially in the expansion tube 21 as the push-pull tube 12 moves. Furthermore, by providing at least one treatment electrode 212 on each branch tube 211, the treatment electrode 212 can be positioned radially in the expansion tube 21 as the branch tube 211 deforms. Meanwhile, by setting a cooling gap 30 that communicates with the external environment between the branch pipe 211 and the treatment electrode 212, a first infusion channel 111 is set on the main pipe 11, and a second infusion channel 2111 is set on the branch pipe 211, and the first infusion channel 111 and the second infusion channel 2111 are connected, and the second infusion channel 2111 is connected with the cooling gap 30, the cold saline in the first infusion channel 111 can be infused into the cooling gap 30 between the branch pipe 211 and the treatment electrode 212 through the second infusion channel 2111, and flow into the external environment, thereby achieving cooling and temperature reduction of the treatment electrode 212. The pulsed electric field ablation catheter does not require an infusion port 2112 on the surface of the treatment electrode 212, thus helping to avoid spark discharge on the treatment electrode 212 and ensuring high reliability. During the ablation operation of the pulsed electric field ablation catheter on the target tissue, cold saline 80 can be discharged to the vicinity of the treatment electrode 212 through the cooling gap 30 and mix with the blood near the treatment electrode 212, thereby reducing the treatment impedance of the treatment electrode 212 and allowing the pulsed electric field generated on the treatment electrode 212 to act on the target tissue more easily. Furthermore, when the treatment electrode 212 has a tip 90, the cold saline 80 discharged from the cooling gap 30 to the vicinity of the treatment electrode 212 can also coat the tip 90 in the form of water droplets, thereby improving the uniformity of the electric field distribution on the end face and tip 90 of the treatment electrode 212 and helping to prevent spark discharge caused by uneven electric field distribution of the treatment electrode 212.

[0059] Figure 8 illustrates an exemplary cooling method provided in this application, which can be applied to pulsed electric field ablation catheters. At least one embodiment of this application provides a cooling method that may include:

[0060] Step 801: Receive the infusion liquid through the first infusion channel.

[0061] Optionally, the infusion fluid can be cold saline or other sterile fluids used for cooling; there is no limitation on this. The following explanation uses cold saline as an example.

[0062] Step 802: The infusion fluid is transported from the first infusion channel to the second infusion channel.

[0063] Step 803: The injection liquid is delivered to the cooling gap through the second injection channel.

[0064] In one possible implementation, the pulsed electric field ablation catheter includes a tube body 10 and an expansion portion 20; the tube body 10 includes a main tube 11 and a push-pull tube 12, the push-pull tube 12 being movably inserted into the main tube 11 and extending at least partially from the distal end of the main tube 11.

[0065] The expansion section 20 includes an expansion tube 21, and multiple branch tubes are formed between the proximal and distal ends of the expansion tube 21.

[0066] The proximal end of the expansion tube 21 is connected to the distal end of the main tube 11, and the distal end of the expansion tube 21 is connected to the distal end of the push-pull tube 1.

[0067] At least one treatment electrode 212 is provided on the branch pipe 211, and a cooling gap 30 communicating with the external environment is provided between the branch pipe 211 and the treatment electrode 212.

[0068] The main pipe 11 is provided with a first injection channel 111, and the branch pipe is provided with a second injection channel 2111. The first injection channel 111 and the second injection channel 2111 are connected, and the second injection channel 2111 is connected to the cooling gap 30.

[0069] Since the main tube 11 is provided with a first infusion channel 111 and the branch tube 211 is provided with a second infusion channel 2111, the first infusion channel 111 and the second infusion channel 2111 are connected, and the second infusion channel 2111 is connected with the cooling gap 30, the infusion liquid (such as cold saline 80) in the first infusion channel 111 can be infused into the cooling gap 30 between the branch tube 211 and the treatment electrode 212 through the second infusion channel 2111 and flow into the external environment, thereby achieving cooling of the treatment electrode 212.

[0070] Figure 9 illustrates another exemplary cooling method provided in this application, which may include:

[0071] Step 901: Receive the infusion fluid through the first infusion channel.

[0072] Step 902: The infusion fluid is delivered from the first infusion channel to the diversion chamber.

[0073] Step 903: Transfer the infusion fluid from the diversion chamber to the second infusion channel.

[0074] The first and second injection channels are connected by a shunt chamber, which consists of the gap between the proximal end of the expansion tube and the distal end of the main tube, as well as the inner wall of the connecting tube. The connecting tube is used to connect the expansion tube and the main tube.

[0075] Since a diversion cavity is provided between the first injection channel and the second injection channel, and the diversion cavity is simultaneously connected to at least one second injection channel, it is beneficial to uniformly inject the injection liquid in the first injection channel into at least one second injection channel.

[0076] In one possible implementation, the number of first infusion channels is a first value, which can be set based on requirements and is not limited here. For example, the number of first infusion channels can be 1.

[0077] Since each branch tube has an electrode, and each electrode requires a corresponding second infusion channel for cooling, but the diameter of the main tube 11 is limited, the more infusion channels are set in the main tube 11, the smaller the inner diameter of a single infusion channel becomes, and the utilization rate of the main tube 11 will decrease, resulting in limited infusion liquid in the infusion channels and a poorer cooling effect on the electrodes. If a single first infusion channel 111 is set on the main tube 11, and the first infusion channel 111 is connected to multiple second infusion channels 2111 through the shunt cavity 40, then there is no need to set multiple corresponding infusion channels on the main tube 11, which improves the space utilization rate of the main tube 11 and effectively increases the cold saline infusion flow rate of the pulse electric field ablation catheter.

[0078] Step 904: The injection liquid is delivered from the second injection channel to the cooling gap through the injection hole.

[0079] The second infusion channel is connected to the cooling gap through an infusion hole; the infusion hole is located on the branch pipe, and the position of the infusion hole corresponds to the position of the treatment electrode.

[0080] In one possible implementation, each branch pipe has at least one second injection channel. Each second injection channel on the branch pipe corresponds to at least one injection hole.

[0081] Step 905: The perfusion fluid is delivered from the cooling gap to the area around the treatment electrode.

[0082] When the pulsed electric field ablation catheter perfuses and cools the treatment electrode 212 through cold saline 80, the cold saline 80 is discharged into the vicinity of the treatment electrode 212 through the cooling gap 30, increasing the contact area between the treatment electrode 212 and the blood 60. Furthermore, the cold saline 80 has a certain degree of conductivity, and its impedance is generally lower than that of the blood 60. Therefore, the cold saline 80 can mix with the blood 60 near the treatment electrode 212 to form a mixed conductive solution 70. This may help reduce the treatment impedance of the treatment electrode 212, allowing the pulsed electric field generated on the treatment electrode 212 to more easily act on the target tissue, thus improving the treatment effect of the treatment electrode 212.

[0083] In one possible implementation, perfusion fluid is delivered to the perfusion fluid surrounding the treatment electrode to encapsulate the tip on the treatment electrode.

[0084] When there is a tip on the treatment electrode, the infusion liquid can wrap the tip 90 in the form of water droplets, which helps to improve the uniformity of the electric field distribution on the end face of the treatment electrode 212 and the tip 90, and helps to prevent spark discharge caused by uneven electric field distribution of the treatment electrode 212.

[0085] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A pulsed electric field ablation catheter, comprising: The pulsed electric field ablation catheter includes: The tube body includes a main tube and a push-pull tube, the push-pull tube being movably inserted inside the main tube and extending at least partially from the distal end of the main tube; An expansion section, comprising an expansion tube, wherein a plurality of branch tubes are formed between the proximal and distal ends of the expansion tube, the proximal end of the expansion tube is connected to the distal end of the main tube, and the distal end of the expansion tube is connected to the distal end of the push-pull tube. At least one treatment electrode is provided on the branch tube, and a cooling gap communicating with the external environment is provided between the branch tube and the treatment electrode. The main tube is provided with a first injection channel, and the branch tube is provided with a second injection channel. The first injection channel is connected to the second injection channel, and the second injection channel is connected to the cooling gap.

2. The pulse field ablation catheter of claim 1, wherein, The expansion tube is sleeved outside the push-pull tube. The expansion part also includes a first sealing member, which is disposed on the proximal end of the expansion tube and located between the expansion tube and the push-pull tube, for sealing the gap between the expansion tube and the push-pull tube.

3. The pulsed electric field ablation catheter according to claim 1 or 2, characterized in that, The tube body also includes a connecting tube, the two ends of which are respectively sleeved or fixed on the proximal end of the expansion tube and the distal end of the main tube, for connecting the expansion tube and the main tube.

4. The pulsed electric field ablation catheter according to claim 3, characterized in that, A diversion cavity is formed between the proximal end of the expansion tube, the distal end of the main tube, and the inner wall of the connecting tube, and the first injection channel and the second injection channel can be connected through the diversion cavity.

5. The pulsed electric field ablation catheter according to claim 4, characterized in that, The main tube is provided with a push-pull channel, and the push-pull tube can move axially within the push-pull channel. The push-pull channel is connected to the diversion cavity.

6. The pulsed electric field ablation catheter according to claim 4 or 5, characterized in that, There is a gap between the proximal end of the expansion tube and the distal end of the main tube, thereby forming at least a portion of the diversion cavity.

7. The pulsed electric field ablation catheter according to any one of claims 1-6, characterized in that, The branch pipe is provided with an infusion hole, the position of which corresponds to the position of the treatment electrode, and is used to connect the second infusion channel and the cooling gap.

8. The pulsed electric field ablation catheter according to claim 7, characterized in that, A cooling recess is provided on the outer wall of the branch tube. The position of the cooling recess corresponds to the position of the treatment electrode. A cooling gap is formed between the cooling recess and the treatment electrode. The two ends of the infusion hole are respectively connected to the cooling gap formed on the cooling recess and the second infusion channel.

9. The pulsed electric field ablation catheter according to claim 8, characterized in that, The treatment electrode is a ring electrode, which is sleeved on the branch tube.

10. The pulsed electric field ablation catheter according to any one of claims 1-9, characterized in that, There are multiple cooling recesses and multiple injection holes. The multiple cooling recesses are arranged at intervals along the circumference of the branch pipe, and the multiple injection holes correspond one-to-one with the multiple cooling recesses.

11. The pulsed electric field ablation catheter according to claim 10, characterized in that, There are two cooling recesses and two injection holes. The two cooling recesses are respectively located on both sides of the branch pipe in the circumferential direction of the expansion pipe, and the two injection holes correspond to the two cooling recesses respectively.

12. The pulsed electric field ablation catheter according to claim 2, characterized in that, The first sealing element includes a sealing tube, which passes through the expansion tube and is sleeved on the push-pull tube. The outer side wall of the sealing tube is fixedly connected to the inner side wall of the expansion tube, and the inner side wall of the sealing tube abuts against the outer side wall of the push-pull tube.

13. The pulsed electric field ablation catheter according to claim 2 or 12, characterized in that, The first seal is elastic.

14. The pulsed electric field ablation catheter according to any one of claims 1 to 13, characterized in that, The branch tube is provided with a plurality of treatment electrodes, which are spaced apart along the extension direction of the branch tube.

15. The pulsed electric field ablation catheter according to claim 14, characterized in that, The plurality of therapeutic electrodes are spaced apart in the middle of the branch tube.

16. The pulsed electric field ablation catheter according to claim 15, characterized in that, The distance between two adjacent treatment electrodes is 1.5-3 mm.

17. The pulsed electric field ablation catheter according to any one of claims 1 to 16, characterized in that, The expansion section further includes a second seal, which is disposed at the distal end of the expansion tube and is used to seal the distal end of the second injection channel.

18. The pulsed electric field ablation catheter according to claim 17, characterized in that, The second seal is elastic.

19. The pulsed electric field ablation catheter according to any one of claims 1-18, characterized in that, The first infusion channel, the second infusion channel, and the cooling gap can be filled with infusion liquid, which can encapsulate the tip of the treatment electrode.

20. A cooling method, characterized in that, A pulsed electric field ablation catheter is used in this application. The pulsed electric field ablation catheter includes a tube body and an expansion section. The tube body includes a main tube and a push-pull tube, the push-pull tube being movably inserted into the main tube and extending at least partially from the distal end of the main tube. The expansion section includes an expansion tube, with multiple branch tubes formed between the proximal and distal ends of the expansion tube. The proximal end of the expansion tube is connected to the distal end of the main tube, and the distal end of the expansion tube is connected to the distal end of the push-pull tube. At least one treatment electrode is disposed on each branch tube, and a cooling gap communicating with the external environment is provided between the branch tube and the treatment electrode. A first infusion channel is provided on the main tube, and a second infusion channel is provided on each branch tube. The first infusion channel communicates with the second infusion channel, and the second infusion channel communicates with the cooling gap. The method includes: The infusion fluid is received through the first infusion channel; The infusion fluid is transported from the first infusion channel to the second infusion channel; The injection liquid is delivered to the cooling gap through the second injection channel.

21. The cooling method according to claim 20, characterized in that, The first infusion channel and the second infusion channel are connected by a diversion cavity; the diversion cavity is formed by the gap between the proximal end of the expansion tube and the distal end of the main tube and the inner wall of the connecting tube; the connecting tube is used to connect the expansion tube and the main tube; The step of conveying the infusion fluid from the first infusion channel to the second infusion channel includes: The infusion fluid is delivered from the first infusion channel to the diversion chamber; The infusion fluid is transferred from the diversion chamber to the second infusion channel.

22. The cooling method according to claim 20 or 21, characterized in that, The second infusion channel is connected to the cooling gap through an infusion hole; the infusion hole is located on the branch pipe, and the position of the infusion hole corresponds to the position of the treatment electrode; The step of delivering the infusion liquid from the second infusion channel to the cooling gap includes: The injection liquid is delivered from the second injection channel to the cooling gap through the injection hole.

23. The cooling method according to any one of claims 20-22, characterized in that, After the infusion liquid is delivered from the second infusion channel to the cooling gap, the method further includes: The infusion fluid is delivered through the cooling gap to the area around the treatment electrode.

24. The cooling method according to claim 23, characterized in that, The perfusion fluid delivered to the periphery of the treatment electrode is used to encapsulate the tip of the treatment electrode.

25. The method according to any one of claims 20-24, characterized in that, The number of the first infusion channels on each of the branch tubes is at least one.

26. The method according to any one of claims 20-25, characterized in that, The number of the second infusion channels is the first value.

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