Ablation device, impedance detection method, and pulsed electric field ablation system

Abstract

The application provides an ablation device, an impedance detection method and a pulsed electric field ablation system. The ablation device comprises an impedance detection circuit, a pulsed ablation circuit and a catheter, and the impedance detection circuit is used for detecting the equivalent impedance of the pulsed ablation circuit before the pulsed ablation circuit performs discharge ablation work. In this way, the reasonable design of the control logic can be matched with the working mode of the multi-electrode, thereby solving the problem that the ablation device with multiple electrodes in the prior art lacks comprehensive detection means.

Description

Technical Field

[0001] This invention relates to the field of pulsed electric field ablation technology, and particularly to an ablation device, an impedance detection method, and a pulsed electric field ablation system. Background Technology

[0002] Catheter ablation based on pulmonary vein isolation is one of the important methods for treating atrial fibrillation. Currently, the commonly used ablation methods in clinical practice often use radiofrequency energy or cryoablation energy. However, regardless of radiofrequency or cryoablation, the ablation energy lacks selectivity in destroying the tissue in the ablation area and depends on the adhesion of the catheter, which may cause damage to the adjacent esophagus, coronary arteries, and phrenic nerve. In addition, since radiofrequency and cryoablation are thermal ablation techniques, they are limited by the heat sink effect, making it difficult to achieve full-thickness transmural ablation, which affects the treatment effect.

[0003] Cardiac pulsed electric field ablation is a novel ablation method that utilizes pulsed electric fields as energy. By designing an appropriate pulsed electric field, various pulse waveforms with low pulse widths (microseconds or even nanoseconds) and high voltages are combined to release ablation energy, creating tiny pores—electroporation—in the cell membranes of cardiomyocytes. This disrupts the ion balance inside and outside the cardiomyocytes, inducing cardiomyocyte death. Compared to traditional radiofrequency and cryotherapy, pulsed electric field ablation is a non-thermal ablation method. Furthermore, because cardiomyocytes have the lowest pulsed electric field threshold, the pulsed electric field can selectively damage the myocardium while preserving blood vessels, nerves, and surrounding tissues such as the lungs, esophagus, and phrenic nerve.

[0004] Pulse ablation systems utilize a variety of catheter types, with each manufacturer offering variations in the number, shape, and discharge mode of catheter electrodes. A growing number of clinicians indicate that multi-electrode, bipolar, or multipolar discharge modes represent the future direction. Bipolar or multipolar discharge modes refer to discharge between one or more pairs of catheter electrodes. With proper parameter design, bipolar or multipolar discharge modes, compared to monopolar discharge modes (catheter electrodes discharging onto a neutral electrode plate), largely eliminate the problem of muscle contraction. Furthermore, bipolar or multipolar discharge modes are highly efficient, forming a ring-shaped ablation foci in a single or segmented application. Using specially shaped multi-coil, multi-electrode catheters allows for simultaneous three-dimensional spiral ablation of pulmonary veins, improving pulmonary vein isolation efficiency and shortening procedure time. However, multi-coil, multi-electrode catheters, due to their numerous electrodes, pose a risk of short circuits caused by electrodes of different polarities overlapping within the patient's body. Short circuits between electrodes of different polarities can cause excessive instantaneous current, damaging internal switching components and potentially injuring the patient. Therefore, pulse ablation systems need to be capable of configuring different discharge modes and detecting short circuits in catheter electrodes under different discharge modes.

[0005] Furthermore, the success rate of pulsed ablation system procedures depends on the adhesion between the catheter electrode and the tissue. Better adhesion results in deeper ablation lesions, increasing the likelihood of pulmonary vein isolation. Good tissue adhesion also prevents the formation of air bubbles and air embolisms. For pressure-sensitive catheters, the adhesion can generally be determined by the pressure value collected by the pressure sensor on the catheter electrode at the catheter tip. However, for multi-coil, multi-electrode catheters, due to their structure and manufacturing process, it is difficult to use the same method to determine the adhesion.

[0006] In summary, existing multi-electrode ablation devices lack comprehensive detection methods for various application scenarios and operating modes. For example, they lack short-circuit detection for various discharge modes such as monopolar, bipolar, and multipolar; detection of discharge and non-discharge segments, segment impedance and overall impedance; and the ability to quickly determine whether there is a risk of short circuit or excessive distance between the catheter electrodes in the multi-electrode pulse ablation catheter; and the degree of contact between the catheter electrodes and the tissue. Summary of the Invention

[0007] The purpose of this invention is to provide an ablation device, an impedance detection method, and a pulsed electric field ablation system to solve the problem that existing multi-electrode ablation devices lack comprehensive detection methods.

[0008] To address the aforementioned technical problems, according to a first aspect of the present invention, an ablation device is provided, the ablation device comprising an impedance detection circuit, a pulse ablation circuit, and a catheter, the pulse ablation circuit comprising a switching module and at least two catheter electrodes, the switching module being used to control each of the catheter electrodes to independently disconnect, become a positive electrode, or become a negative electrode, the at least two catheter electrodes being sequentially arranged along the catheter.

[0009] The impedance detection circuit is used to detect the equivalent impedance of the pulse ablation circuit before the pulse ablation circuit performs discharge ablation.

[0010] Optionally, the conduit is spiral-shaped.

[0011] Optionally, the impedance detection circuit includes an impedance detection module and an impedance detection branch.

[0012] The impedance module is used to detect the equivalent impedance of the circuit connected to it.

[0013] The impedance detection branch is used to connect the pulse ablation circuit and the impedance detection module, and a compensation resistor is connected in series between the pulse ablation circuit and the impedance detection module.

[0014] Optionally, the impedance detection circuit may further include at least one of a calibration branch, a lower limit branch, and an upper limit branch.

[0015] The calibration branch, the lower limit branch, the upper limit branch, and the impedance detection branch are independently connected to or disconnected from the impedance detection module via switching elements.

[0016] When the calibration branch is connected to the impedance detection module, it provides a calibration resistor. The impedance detection module configures calibration parameters based on the detected impedance and the pre-stored resistance value of the calibration resistor.

[0017] When the lower limit branch is connected to the impedance detection module, it provides a lower limit resistor. The impedance detection module obtains the lower limit accuracy based on the detected impedance and the pre-stored resistance value of the lower limit resistor.

[0018] When the upper limit branch is connected to the impedance detection module, it provides an upper limit resistor. The impedance detection module obtains the upper limit accuracy based on the detected impedance and the pre-stored resistance value of the upper limit resistor.

[0019] The lower limit resistor and the upper limit resistor are set based on the range of the equivalent impedance when the ablation device is working normally.

[0020] To solve the above-mentioned technical problems, according to a second aspect of the present invention, an impedance detection method is provided, which is applied to the above-mentioned ablation device.

[0021] The impedance detection method includes: outputting a control signal to drive the state of each switching element in the switching module to conform to a preset state; detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit; and obtaining the detection result based on the equivalent impedance.

[0022] Optionally, the impedance detection circuit further includes an impedance detection module and an impedance detection branch. Before detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, the impedance detection method further includes the following steps:

[0023] The output control signal drives the impedance detection branch to be individually connected to the pulse ablation circuit, the compensation resistor, and the impedance detection module.

[0024] Optionally, the impedance detection circuit further includes at least one of a calibration branch, a lower limit branch, and an upper limit branch. Before detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, the impedance detection method, based on the specific structure of the impedance detection circuit, also adaptively includes at least one of the following steps:

[0025] The output control signal drives the calibration branch to connect independently to the impedance detection module, which configures the calibration parameters.

[0026] The output control signal drives the lower limit branch to connect independently to the impedance detection module, and the impedance detection module obtains the accuracy of the lower limit value.

[0027] Determine whether the accuracy of the lower limit value meets the operational requirements.

[0028] The output control signal drives the upper limit branch to connect separately to the impedance detection module, and the impedance detection module obtains the accuracy of the upper limit value.

[0029] In addition, it is determined whether the accuracy of the upper limit value meets the working requirements.

[0030] Optionally, the catheter is spiral-shaped, and the catheter is configured with turns from the inside to the outside, from the 1st turn to the N1th turn, where N1 is the total number of turns of the catheter. The impedance detection method includes:

[0031] The output control signal drives each switching element in the switching module to be turned on or off, making the conduit electrode in the i-th turn one of the positive and negative poles, making the conduit electrode in the (i+1)-th turn the other of the positive and negative poles, and turning off the other conduit electrodes; where i ranges from 1 to N1-2.

[0032] For each different value of i, the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit.

[0033] Calculate R 标称 = The sum of the equivalent impedances corresponding to all different values ​​of i ÷ N2, where N2 is the total number of catheter electrodes in the first to the N1-1th turns.

[0034] And, R 标称 Set to the nominal resistance value of the catheter electrode.

[0035] Optionally, the catheter electrodes are configured as the first to the Mth catheter electrodes along the catheter, where M is the total number of catheter electrodes, and the impedance detection method includes:

[0036] The output control signal drives each switching element in the switching module to be turned on or off, making the j-th conduit electrode one of the positive and negative poles, making the (j+1)-th conduit electrode the other of the positive and negative poles, and turning off the other conduit electrodes; wherein the value of j ranges from 1 to M-1.

[0037] For each different value of j, the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit and set as R. j .

[0038] If R1>A*R 标称, it is determined that the first catheter electrode is in good apposition; if R1≤B*R 标称 , it is determined that the first catheter electrode is in poor apposition; in other cases, it is determined that the first catheter electrode is in fair apposition.

[0039] When j≠1, if R j >A*R 标称 and R j-1 >A*R 标称 , it is determined that the j-th catheter electrode is in good apposition; if R j ≤B*R 标称 and R j-1 ≤B*R 标称 , it is determined that the j-th catheter electrode is in poor apposition; in other cases, it is determined that the j-th catheter electrode is in fair apposition.

[0040] If R M-1 >A*R 标称 , it is determined that the M-th catheter electrode is in good apposition; if R M-1 ≤B*R 标称 , it is determined that the M-th catheter electrode is in poor apposition; in other cases, it is determined that the M-th catheter electrode is in fair apposition.

[0041] Wherein, A and B are preset parameters, and A>B.

[0042] Optionally, the catheter electrodes are arranged along the catheter as the first catheter electrode to the M-th catheter electrode, M is the total number of the catheter electrodes, and the impedance detection method comprises:

[0043] Outputting a control signal to drive each switching element in the switching module to turn on or off, so that the j1-th catheter electrode becomes one of the positive and negative poles, the j2-th catheter electrode becomes the other of the positive and negative poles, and the other catheter electrodes are disconnected; wherein the ordered array (j1, j2) traverses all cases where j1<j2, the value range of j1 is 1 to M, and the value range of j2 is 1 to M.

[0044] For each different ordered array (j1, j2), detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, and determining whether the equivalent impedance is less than a first short-circuit threshold; if it is less than the first short-circuit threshold, it is determined that a short circuit exists between the j1-th catheter electrode and the j2-th catheter electrode.

[0045] Optionally, the catheter electrodes are arranged along the catheter as the first catheter electrode to the M-th catheter electrode, M is the total number of the catheter electrodes, and the impedance detection method comprises:

[0046] outputs a control signal to drive each switching element in the switch module to turn on or off, so that the j1-th catheter electrode becomes one of the positive and negative electrodes, the j2-th to M-th catheter electrodes become the other of the positive and negative electrodes, and the other catheter electrodes are disconnected; wherein the ordered array (j1, j2) traverses all cases where j1<j2, j1 ranges from 1 to M, and j2 ranges from 1 to M.

[0047] For each different ordered array (j1, j2), the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit, and it is determined whether the equivalent impedance is less than a second short-circuit threshold; if it is less, it is determined that at least one of the j1-th catheter electrode and the j2-th to M-th catheter electrodes has a short circuit condition.

[0048] Optionally, the discharge ablation operation is implemented based on the complete catheter, and the impedance detection method comprises:

[0049] Before the discharge ablation operation, outputting a control signal to drive each switching element in the switch module to turn on or off, so that the connection state of all the catheter electrodes is consistent with the connection state in the upcoming discharge ablation operation.

[0050] And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is less than a third short-circuit threshold, determining to end the discharge ablation operation if it is less; otherwise, continuing.

[0051] Optionally, the catheter electrodes are arranged along the catheter into at least two segments, the catheter electrodes in the same segment are adjacent to each other end to end, and each discharge ablation step in the discharge ablation operation is implemented based on one segment in the catheter; the impedance detection method comprises:

[0052] During the execution of the discharge ablation operation, before each discharge ablation step, the following steps are executed:

[0053] outputting a control signal to drive each switching element in the switch module to turn on or off, so that the catheter electrodes in the segment to be used for discharge ablation become one of the positive and negative electrodes, and the other catheter electrodes become the other of the positive and negative electrodes.

[0054] detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is less than a fourth short-circuit threshold, determining to end the discharge ablation operation if it is less; otherwise, continuing.

[0055] The output control signal drives each switching element in the switching module to be turned on or off, so that the catheter electrode in the section to be used for discharge ablation becomes one of the positive and negative poles, and the other catheter electrodes become the other of the positive and negative poles.

[0056] The equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit. If the equivalent impedance is less than the fifth short-circuit threshold, the discharge ablation operation is terminated; otherwise, it continues.

[0057] The output control signal drives each switching element in the switching module to turn on or off, so that the connection state of all the catheter electrodes is consistent with the connection state during the upcoming discharge ablation operation.

[0058] Furthermore, based on the impedance detection circuit, the equivalent impedance of the pulse ablation circuit is detected. If the equivalent impedance is less than the fifth short-circuit threshold, the discharge ablation operation is terminated; otherwise, it continues.

[0059] To address the aforementioned technical problems, according to a third aspect of the present invention, a pulsed electric field ablation system is provided, the pulsed electric field ablation system comprising a control module and the aforementioned ablation device, the control module being used to perform the aforementioned impedance detection method based on the ablation device.

[0060] Optionally, the control module is used to determine whether to control the ablation device to perform discharge ablation work based on the information obtained after the impedance detection method is executed.

[0061] Compared with existing technologies, the present invention provides an ablation device, impedance detection method, and pulsed electric field ablation system. The ablation device includes an impedance detection circuit, a pulsed ablation circuit, and a catheter. The impedance detection circuit is used to detect the equivalent impedance of the pulsed ablation circuit before the pulsed ablation circuit performs discharge ablation. This configuration, coupled with a rationally designed control logic, can match the working mode of multi-electrode systems, thus solving the problem of the lack of comprehensive detection methods in existing multi-electrode ablation devices. In some embodiments of the present invention, the following beneficial technical effects are achieved: 1. Multiple discharge modes such as unipolar discharge, bipolar discharge, and multipolar discharge can be configured. 2. The discharge polarity of the catheter electrodes can be arbitrarily configured, and the service life of switching elements can be improved by alternately switching the discharge electrode polarity. In further embodiments, the ablation device combined with related impedance detection methods achieves the following beneficial effects: 3. Multiple impedance detection methods can be used, such as unipolar impedance, arbitrary bipolar impedance, comprehensive impedance of the discharge segment, and impedance of the discharge segment and non-discharge segment. 4. Short circuits or excessive proximity of electrodes in the multi-electrode cardiac pulsed electric field ablation system can be quickly determined. 5. It can perform adhesion quality testing and indicate the adhesion status. In clinical treatment, it can perform multiple different ablation techniques with a single device, shortening operation time and reducing patient pain, while ensuring the effectiveness, reliability, and safety of the ablation process through multiple impedance detection methods; significant progress has been made. Attached Figure Description

[0062] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0063] Figure 1 This is a schematic diagram of the appearance of a spiral conduit according to an embodiment of the present invention;

[0064] Figure 2 This is a schematic diagram of the circuit portion of an ablation device according to an embodiment of the present invention;

[0065] Figure 3 This is a schematic diagram of the circuit structure of an impedance detection circuit according to an embodiment of the present invention;

[0066] Figure 4 This is a schematic diagram of the nominal impedance detection and contact quality detection process according to an embodiment of the present invention;

[0067] Figure 5 This is a schematic diagram of the process of interleaving discharge ablation and impedance detection methods according to an embodiment of the present invention;

[0068] Figure 6 This is a curve showing the relationship between the electrode spacing and inter-electrode impedance according to an embodiment of the present invention;

[0069] Figure 7 This is a curve showing the relationship between the average impedance P of adjacent catheter electrodes and the combined impedance Z of the discharge segment, and the segment impedance D of the discharge segment and the non-discharge segment, according to an embodiment of the present invention.

[0070] in:

[0071] 1-Pulse generating circuit; 2-Switching module; 3-Impedance detection circuit; 4-Conduit electrode; 5-Neutral electrode.

[0072] 31-Impedance detection module; 32-Calibration branch; 33-Lower limit branch; 34-Upper limit branch; 35-Impedance detection branch. Detailed Implementation

[0073] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0074] As used in this invention, the singular forms “a,” “an,” and “the” include plural objects; the term “or” is generally used to mean “and / or”; the term “a number” is generally used to mean “at least one”; the term “at least two” is generally used to mean “two or more”; furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," and "third" may explicitly or implicitly include one or at least two of those features. The term "proximal" typically refers to the end closer to the operator, and the term "distal" typically refers to the end closer to the patient. "One end" and "the other end," as well as "proximal" and "distal," generally refer to two corresponding parts, including not only endpoints. The terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; they can be internal connections between two elements or interactions between two elements. Furthermore, as used in this invention, the placement of one element on another element generally only indicates a connection, coupling, cooperation, or transmission relationship between the two elements, and the connection, coupling, cooperation, or transmission between the two elements can be direct or indirect through an intermediate element. It should not be construed as indicating or implying a spatial positional relationship between the two elements, i.e., one element can be located arbitrarily inside, outside, above, below, or to one side of another element, unless otherwise explicitly stated. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0075] The core idea of ​​this invention is to provide an ablation device, an impedance detection method, and a pulsed electric field ablation system to solve the problem that existing multi-electrode ablation devices lack comprehensive detection methods.

[0076] The following description refers to the accompanying drawings.

[0077] This embodiment provides a multi-electrode cardiac pulsed electric field ablation device (i.e., ablation device), including a spiral catheter, the appearance of which is as follows. Figure 1 As shown, in Figure 1 The figure shows the appearance of a spiral catheter with 24 catheter electrodes, where r and R schematically represent the inner and outer radii of the spiral catheter, respectively.

[0078] It is understood that in other embodiments, the shape of the catheter is not limited to a spiral shape, and different shapes of catheters can be provided based on different treatment goals. Therefore, it can also be considered that the ablation device includes a catheter.

[0079] Figure 1 The "1#" and other "number + #" labels indicate the first to the 24th catheter electrodes, respectively.

[0080] Please refer to Figure 2 Its circuitry includes: a pulse generation circuit 1, an impedance detection circuit 3, and a pulse ablation circuit. The pulse ablation circuit further includes a switching module 2, a neutral electrode 5 (i.e., a neutral electrode plate), and at least two conduit electrodes 4.

[0081] Switch module 2 is used to control each catheter electrode to independently disconnect, become positive, or become negative, with at least two catheter electrodes sequentially arranged along the spiral catheter (in... Figure 1 (As already indicated in the text). Figure 2 The "1#" and other "number + #" labels indicate catheter electrodes numbered 1 through 24, respectively. Figure 2 The designations “20” to “2N”, which are “2+number” designations, are used to refer to conduit electrode branches that include conduit electrodes and related switching elements. N is the total number of conduit electrodes, for example, 24 in this embodiment. Figure 2 The designations “K2001” to “K2N01” and “K2002” to “K2N02” refer to the positive and negative switching elements in the aforementioned conduit electrode branch, respectively. Figure 2 In this diagram, HVP represents the positive output terminal of pulse generator circuit 1, and HVN represents the negative output terminal of pulse generator circuit 1.

[0082] Switching module 2 is also used to turn on or off the high-voltage pulse energy generated by the internal pulse generating circuit through switching elements K201 and K202.

[0083] The switching element set in the switching module 2 can be one or a combination of relays, IGBTs, and MOSFETs, or it can be a module circuit built based on relays, IGBTs, MOSFETs, transistors, and other components.

[0084] Existing technologies only utilize impedance detection to determine the adhesion between the catheter electrode and human tissue, or to determine if a single catheter electrode has a short circuit. No solutions have been proposed for using impedance detection to determine if short circuits occur between multiple catheter electrodes, and no specific circuitry has been disclosed. Furthermore, while most existing pulse ablation systems incorporate impedance detection circuits, even when using such circuits to determine short circuits between multiple catheter electrodes, they generally only detect the impedance between adjacent electrodes; short circuits between non-adjacent electrodes can only be indirectly determined by comparing the impedances of adjacent electrodes one by one, which is neither intuitive nor time-consuming. For multi-coil, multi-electrode catheters, it is impossible to directly detect the impedance between the discharge segment and the non-discharge segment, or between the positive and negative electrodes within the discharge segment. Short circuits between the positive and negative electrodes within the discharge segment can cause excessive bus current, damaging switching components; if the catheter electrodes in the discharge and non-discharge segments are too close to the discharge catheter electrode, an electric arc can occur, affecting the treatment effect. The pulse ablation system should identify and avoid discharging in both of these situations.

[0085] In this embodiment, it cannot be simply assumed that only the impedance detection circuit 3 is innovative. The setting of the multi-electrode pulse ablation circuit in this embodiment facilitates the cooperation between the pulse ablation circuit and the impedance detection circuit, and facilitates the coordination between the two by the external control system. Furthermore, the pulse ablation circuit itself provides the prerequisite for the realization of multiple working modes.

[0086] The structure of the switching circuit can also be described as follows: each conduit electrode and neutral electrode are connected to the positive output terminal of the pulse generation circuit through an independent switching element, and each conduit electrode and neutral electrode are connected to the negative output terminal of the pulse generation circuit through an independent switching element.

[0087] by Figure 2 Taking the illustrated embodiment as an example, the following discharge mode can be achieved.

[0088] 1. Unipolar discharge mode: Discharge between any conduit electrode and the neutral electrode plate.

[0089] Taking the unipolar discharge between the first conduit electrode on branch 21 and the neutral electrode on branch 20 as an example, the logic is as follows: close K2001 and K201 to connect the neutral electrode to the positive DC bus HVP (positive terminal of the pulse generation circuit); close K2102 and K202 to connect the first conduit electrode to the negative DC bus HVN (negative terminal of the pulse generation circuit), and at the same time disconnect other switches to form a closed discharge circuit.

[0090] 2. Bipolar discharge mode: Discharge between any two electrode pairs of the conduit.

[0091] Taking the bipolar discharge of the first conduit electrode of branch 21 and the third conduit electrode of branch 23 as an example, the logic is as follows: close K2101 and K201 to connect conduit electrode 1 to the positive DC bus HVP; close K2302 and K202 to connect conduit electrode 3 to the negative DC bus HVN, and at the same time disconnect other switches to form a closed discharge circuit.

[0092] 3. Multi-stage discharge mode: discharge between any number of pairs of conduit electrodes.

[0093] Taking the multi-stage discharge of the 1st, 3rd, and 5th conduit electrodes on branches 21, 23, and 25 with the 2nd, 4th, and 6th conduit electrodes on branches 22, 24, and 26 as an example, the logic is as follows: Close K2101, K2301, K2501, and K201 to connect the 1st, 3rd, and 5th conduit electrodes to the positive DC bus HVP; close K2202, K2402, K2602, and K202 to connect the 2nd, 4th, and 6th conduit electrodes to the negative DC bus HVN, while simultaneously disconnecting other switches to form a closed discharge circuit.

[0094] 4. Adjustable polarity of the discharge conduit electrode: Any discharge conduit electrode can be switched to either positive or negative polarity.

[0095] Taking the first, third, and fifth conduit electrodes on branches 21, 23, and 25 as positive polarity (positive DC bus HVP) and the second, fourth, and sixth conduit electrodes on branches 22, 24, and 26 as negative polarity (negative DC bus HVN) as an example of multi-stage discharge, the implementation logic is shown in Table 1:

[0096] Table 1. On / off states of each switching element

[0097]

[0098]

[0099] In Table 1, X indicates that it is not connected to any DC bus and is floating.

[0100] Taking the multi-stage discharge of the first, third, and fifth conduit electrodes 1, 3, and 5 on branches 21, 23, and 25 as negative polarity (negative DC bus HVN) and the second, fourth, and sixth conduit electrodes 2, 4, and 6 on branches 22, 24, and 26 as positive polarity (positive DC bus HVP) as an example, the implementation logic is shown in Table 2:

[0101] Table 2. On / off states of each switching element

[0102]

[0103] In Table 2, X indicates that it is not connected to any DC bus and is floating.

[0104] The advantage of switchable polarity of the conduit electrode is that it is flexible and convenient to configure. The discharge process can be completed using both of the above methods. In addition, each conduit electrode is equipped with two switches, and switching them in turn can improve the service life of a single switching element.

[0105] The impedance detection circuit is used to detect the equivalent impedance of the pulse ablation circuit before it performs discharge ablation. The impedance detection circuit is connected to the pulse ablation circuit based on switching elements K111 and K112.

[0106] With the above settings and an impedance detection method, detection can be performed in various modes and scenarios.

[0107] The impedance detection method includes: outputting a control signal to drive the state of each switching element in the switching module to conform to a preset state; detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit; and obtaining the detection result based on the equivalent impedance.

[0108] The possible detection methods are listed below:

[0109] 1. Unipolar impedance detection: Impedance detection between any catheter electrode and the neutral electrode.

[0110] Taking the unipolar impedance detection between the first conduit electrode of branch 21 and the neutral electrode of branch 20 as an example, the logic is as follows: close K2001 and K311 to connect the neutral electrode to the positive impedance detection terminal ZP; close K2102 and K312 to connect the first conduit electrode to the negative impedance detection terminal ZN, and at the same time disconnect other switches to form a closed impedance detection circuit.

[0111] 2. Bipolar impedance detection: Impedance detection between any two catheter electrode pairs.

[0112] Taking the bipolar impedance detection between the first conduit electrode of branch 21 and the third conduit electrode of branch 23 as an example, the logic is as follows: close K2101 and K311 to connect conduit electrode 1 to the positive impedance detection terminal ZP; close K2302 and K312 to connect conduit electrode 3 to the negative impedance detection terminal ZN, and at the same time disconnect other switches to form a closed impedance detection circuit.

[0113] 3. Multi-stage impedance detection: Multi-stage impedance detection within the discharge section (comprehensive impedance detection Z);

[0114] If the first to sixth conduit electrodes are discharge conduit electrodes, taking the multi-level integrated impedance detection between the first, third, and fifth conduit electrodes on branches 21, 23, and 25 and the second, fourth, and sixth conduit electrodes on branches 22, 24, and 26 as an example, the implementation logic is as follows: Close K2101, K2301, K2501, and K311 to connect conduit electrodes 1#, 3#, and 5# to the positive impedance detection terminal ZP, so that 1#, 3#, and 5# can be regarded as a single conduit electrode; close K2202, K2402, K2602, and K312 to connect conduit electrodes 2#, 4#, and 6# to the negative impedance detection terminal ZN, so that 2#, 4#, and 6# can be regarded as a single conduit electrode, while simultaneously disconnecting other switches to form a closed impedance detection circuit.

[0115] 4. Multi-stage impedance detection: Multi-stage impedance detection for discharge and non-discharge sections (section impedance detection D);

[0116] If the first to third conduit electrodes are discharge conduit electrodes, and the fourth to sixth conduit electrodes are non-discharge conduit electrodes; taking the first to third conduit electrodes of branches 21, 22, and 23 as segment 1, and the fourth to sixth conduit electrodes of branches 24, 25, and 26 as segment 2 as an example, the impedance detection logic for segment 1 and segment 2 is as follows: Close K2101, K2201, K2301, and K311 to connect conduit electrodes 1#, 2#, and 3# to the positive impedance detection terminal ZP, and 1#, 2#, and 3# can be regarded as a single conduit electrode; close K2402, K2502, K2602, and K312 to connect conduit electrodes 4#, 5#, and 6# to the negative impedance detection terminal ZN, and 4#, 5#, and 6# can be regarded as a single conduit electrode, while simultaneously disconnecting other switches to form a closed impedance detection circuit.

[0117] Please refer to Figure 3 The impedance detection circuit includes an impedance detection module 31, a calibration branch 32, a lower limit branch 33, an upper limit branch 34, and an impedance detection branch 35.

[0118] Impedance modules are used to detect the equivalent impedance of circuits connected to them.

[0119] The calibration branch, lower limit branch, upper limit branch, and impedance detection branch are all independently connected to or disconnected from the impedance detection module via switching elements.

[0120] When the calibration branch is connected to the impedance detection module, a calibration resistor Rcal is provided. The impedance detection module configures calibration parameters based on the detected impedance and the pre-stored resistance value of the calibration resistor. The specific calibration parameters participating in the calibration process can be configured according to actual needs, such as calibration by addition, multiplication, or other methods. The connection relationship between the calibration branch and the impedance detection module is changed through the switching element S301.

[0121] When the lower limit branch is connected to the impedance detection module, a lower limit resistor Rtest1 is provided. The impedance detection module obtains the lower limit accuracy based on the detected impedance and the pre-stored lower limit resistor value. The specific calculation method and unit selection for the lower limit accuracy can be set according to actual needs and will not be described in detail here. The connection relationship between the lower limit branch and the impedance detection module is changed through the switching element S302.

[0122] When the upper limit branch is connected to the impedance detection module, it provides an upper limit resistor Rtest2. The impedance detection module obtains the upper limit accuracy based on the detected impedance and the pre-stored upper limit resistor value. The specific calculation method and unit selection for the upper limit accuracy can be set according to actual needs and will not be described in detail here. The connection relationship between the upper limit branch and the impedance detection module is changed through the switching element S303.

[0123] The lower and upper resistance limits are set based on the range of equivalent impedance when the ablation device is operating normally. If the accuracy of the lower and upper limits does not meet the required standards, whether to stop operation or use another calibration scheme can be set according to actual needs, which will not be described in detail here.

[0124] In other embodiments, only a portion of the calibration branch, lower limit branch, and upper limit branch may be set, or no calibration branch, lower limit branch, and upper limit branch may be set, depending on the actual situation. For example, when the accuracy of the component can be guaranteed by other devices or external constraints.

[0125] The impedance detection branch connects the pulse ablation circuit and the impedance detection module, with a compensation resistor Rcomp connected in series between them. The connection between the pulse ablation circuit and the impedance detection branch is changed by switching elements K311 and K312, while the connection between the impedance detection branch and the impedance detection module is changed by switching element S304.

[0126] The aforementioned switching elements S301, S302, S303, S304, K311, and K312 can be one or more combinations of relays, IGBTs, and MOSFETs, or they can be modular circuits built based on relays, IGBTs, MOSFETs, transistors, etc. Rcal, Rtest1, Rtest2, and Rcomp are all resistors with fixed resistance values, preferably non-inductive resistors with a precision of one-thousandth.

[0127] Based on the above structure, before detecting the equivalent impedance of the pulse ablation circuit using the impedance detection circuit, the impedance detection method further includes:

[0128] The output control signal drives the calibration branch to connect independently to the impedance detection module, which is then configured with calibration parameters. After the pulse device is powered on, switch S301 is closed, and switches S302, S303, S304, K311, and K312 are disconnected, connecting the calibration resistor Rcal to the impedance detection module. Rcal can be selected within the impedance detection range. Calibration parameters are extracted based on this resistor, and other impedance values ​​connected to the impedance detection circuit are detected using these parameters.

[0129] The output control signal drives the lower limit branch to connect independently to the impedance detection module, which then obtains the accuracy of the lower limit value. Switch S302 is closed, and switches S301, S303, S304, K311, and K312 are opened, connecting the verification resistor Rtest1 to the impedance detection main circuit 33. Rtest1 can be the lower limit value of the impedance detection range. After the system is powered on, it checks whether this impedance value is within the accuracy range of the lower limit value, such as meeting a certain percentage deviation, a certain impedance range deviation, or a combination of both. In other words, it determines whether the accuracy of the lower limit value meets the operational requirements.

[0130] The output control signal drives the upper limit branch to connect independently to the impedance detection module, which then obtains the accuracy of the upper limit value. Switch S303 is closed, and S301, S302, S304, K311, and K312 are disconnected, connecting the verification resistor Rtest2 to the impedance detection main circuit 33. Rtest2 can be the upper limit of the impedance detection range. After detecting Rtest1, the system checks whether the impedance value is within the accuracy range of the upper limit of the impedance detection range, such as meeting a certain percentage deviation, a certain impedance range deviation, or a combination of both. In other words, it determines whether the accuracy of the upper limit value meets the operational requirements.

[0131] The output control signal drives the impedance detection branch to connect independently to the pulse ablation circuit, compensation resistor, and impedance detection module. Simultaneously, closing switches S304, K311, and K312 disconnects S301, S302, and S303, connecting the compensation resistor Rcomp and the electrode impedance Relec of the discharge catheter to the impedance detection module. Because there is a risk of short circuits occurring within the patient's body, Relec may approach zero. Relec is... Figure 2 The equivalent resistance is formed by the switching module, catheter electrodes, and neutral electrode. Generally, the lower the impedance connected to the impedance detection module, the worse the impedance detection accuracy. Therefore, a compensation resistor is needed to improve the accuracy of the impedance detection module. The pulse ablation device subtracts the compensation resistor value through a software algorithm to obtain the actual impedance value between the catheter electrodes. The resistance value of Rcomp can be selected based on the impedance detection range and the condition that the catheter electrode impedance is close to zero when the discharge catheter electrode is short-circuited. Relec is the equivalent impedance of the human tissue actually connected between the discharge catheter electrodes, which varies slightly depending on the patient or ablation site. Figure 2Rcomp is not shown in the diagram, but it does exist.

[0132] The above steps can also be adapted to the specific structure of the impedance detection circuit. For example, when no calibration branch is provided, the steps related to the calibration branch can be omitted.

[0133] The following describes several typical testing processes.

[0134] Nominal impedance testing: The blood impedance value within the cardiac chambers is generally lower than that of the myocardial tissue. Based on this, under the guidance of CT imaging or a 3D mapping system, a multi-coil, 24-electrode circular pulse ablation catheter can be placed into the patient's left atrium through a guide sheath. Ensuring it does not contact the atrial tissue, the nominal impedance testing button on the pulse device is pressed, and the blood impedance between adjacent catheter electrodes (1-2, 2-3...23-24) is measured sequentially. This can be used as the nominal impedance value for each catheter electrode. However, due to variations in patient cardiac chamber size and limitations in operator catheter handling skills and viewing angle, it is difficult to guarantee that the outermost catheter electrode will not contact the myocardial tissue in the left atrium of every patient. If any outermost catheter electrode comes into contact with tissue, it will affect the nominal impedance value of that electrode, thus affecting the quality of the electrode's contact test. Figure 1 As shown in the schematic diagram of a multi-coil, 24-electrode annular pulsed ablation catheter, the radius (r) of the inner coil is much smaller than the radius (R) of the outer coil. Therefore, the possibility of the inner coil electrode contacting the patient's myocardial tissue is very small. A preferred approach is to replace the nominal resistance value of each catheter electrode with the average blood impedance between adjacent inner coil electrodes. That is: R 标称 =(R (内圈1-内圈2)血液 +R (内圈2-内圈3)血液 +R (内圈3-内圈4)血液 +…) / N.

[0135] The above can be summarized as follows: the spiral catheter is configured from the inside out as turns 1 to N1, where N1 is the total number of turns of the spiral catheter. Impedance detection methods include:

[0136] The output control signal drives each switching element in the switching module to be turned on or off, making the conduit electrode in the i-th turn one of the positive and negative poles, making the conduit electrode in the (i+1)-th turn the other of the positive and negative poles, and turning off the other conduit electrodes; where i ranges from 1 to N1-2.

[0137] For each different value of i, the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit.

[0138] Calculate R 标称 = The sum of the equivalent impedances corresponding to all different values ​​of i ÷ N2, where N2 is the total number of catheter electrodes in the first to the N1-1th turns.

[0139] And, R 标称 Set to the nominal resistance value of the catheter electrode.

[0140] Contact Quality Detection: After obtaining the nominal impedance of each catheter electrode, the multi-coil, 24-catheter loop pulse ablation catheter can be placed against the left upper pulmonary vein orifice under the guidance of CT imaging or a 3D mapping system. The contact quality detection button on the pulse device is then clicked to perform the contact quality detection. The impedance between adjacent catheter electrodes 1-2, 2-3…23-24 is measured sequentially and used as the contact impedance R. 贴靠 The criterion for determining whether a catheter electrode is in good contact with the surrounding tissue is to compare the contact impedance R between the current catheter electrode and its left and right adjacent catheter electrodes. 贴靠 With nominal impedance R 标称 Taking the third catheter electrode as an example:

[0141] If R (2-3)贴靠 >A*R 标称 R (3-4)贴靠 >A*R 标称 This indicates that the three-conduit electrodes are in good contact.

[0142] If R (2-3)贴靠 ≤B*R 标称 R (3-4)贴靠 ≤B*R 标称 This indicates poor contact between the 3-catheter electrode and the target electrode.

[0143] In other cases, it indicates that the third catheter electrode is generally in contact with the target area.

[0144] Based on animal experiments, parameter A is generally greater than or equal to parameter B.

[0145] The above can be summarized as follows: Catheter electrodes are set as the first to the Mth electrodes along the spiral catheter, where M is the total number of catheter electrodes. Impedance detection methods include:

[0146] The output control signal drives each switching element in the switching module to be turned on or off, making the j-th conduit electrode one of the positive and negative poles, making the (j+1)-th conduit electrode the other of the positive and negative poles, and turning off the other conduit electrodes; where the value of j ranges from 1 to M-1.

[0147] For each different value of j, the equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit and set as R. j .

[0148] If R1>A*R 标称 If the first catheter electrode is properly attached, then the first catheter electrode is considered to be in good contact; if R1≤B*R 标称If the first catheter electrode is not properly attached, it is determined that the first catheter electrode is not properly attached; otherwise, it is determined that the first catheter electrode is properly attached.

[0149] When j≠1, if R j >A*R 标称 And R j-1 >A*R 标称 Then it is determined that the j-th catheter electrode is in good contact; if R j ≤B*R 标称 And R j-1 ≤B*R 标称 If the contact is poor, the j-th catheter electrode is considered to be poorly attached; otherwise, the contact is considered to be adequately attached.

[0150] If R M-1 >A*R 标称 If R M-1 ≤B*R 标称 If the Mth catheter electrode is not properly attached, then the Mth catheter electrode is considered to be properly attached; otherwise, the Mth catheter electrode is considered to be properly attached.

[0151] Among them, A and B are preset parameters.

[0152] Actually, the M here is the same as the N mentioned earlier, but a new letter is chosen to represent it in order to avoid misunderstanding.

[0153] The above-mentioned procedures for nominal impedance testing and bonding quality testing can also be referenced. Figure 4 To understand.

[0154] Figure 4 The document illustrates the procedure applied to the ablation process in this embodiment, including: first, placing the catheter in the left atrium; then, manipulating the catheter to measure the resistance against the left atrium; and finally, the operator performs an impedance test by clicking the "Nominal Impedance Detection" button. The specific operation and calculation process for the impedance test are as described above. After the nominal impedance test is completed, the catheter is manipulated to reach the ideal position of the pulmonary vein, and the operator performs an adhesion test by clicking the "Adhesion Quality Detection" button. The specific operation and calculation process for the adhesion quality test are as described above. If the adhesion is poor, the procedure is repeated; otherwise, the adhesion quality test is completed, and the operator awaits further instructions.

[0155] Short-circuit detection: Catheter electrodes pose a short-circuit risk within the patient's body; the more electrodes present, the greater the risk. Short-circuiting electrodes of different polarities within the discharge section can cause excessive instantaneous current, damaging IGBTs and other switching components, and even injuring the patient. If electrodes in non-discharge sections are too close to the discharge electrode, electric arcs can occur, affecting treatment efficacy. Therefore, it is necessary to identify electrode short circuits or excessive proximity before discharge. Figure 7From the experimental data of electrode spacing and inter-electrode impedance, it can be found that in the same normal saline bath environment, the smaller the electrode spacing, the lower the inter-electrode impedance. Therefore, the inter-electrode impedance of the electrodes can be used to detect whether the discharge electrodes of different polarities are short-circuited or too close to each other. As mentioned above, the impedance detection circuit and the switch circuit in the present application can easily identify such a situation.

[0156] For the impedance detection between each electrode, there are theoretically the following methods:

[0157] An optional solution is the exhaustive method, which selects one electrode and measures the impedance value between this electrode and any other electrode:

[0158] 1-2, 1-3, 1-4, 1-5, 1-6......1-24

[0159] 2-3, 2-4, 2-5, 2-6......2-24

[0160] 3-4, 3-5, 3-6......3-24

[0161] ......

[0162] 23-24

[0163] According to the arithmetic series summation formula, Sn=n(a1+an) / 2, this method requires a maximum of 276 impedance detections, which is relatively time-consuming; however, it can accurately identify the short-circuited electrodes. If any group of detected values is less than a certain threshold during the detection process, it indicates that the electrodes are short-circuited or too close to each other.

[0164] That is, the impedance detection method includes:

[0165] Outputting a control signal to drive each switching element in the switching module to turn on or off, so that the j1-th catheter electrode becomes one of the positive and negative poles, the j2-th catheter electrode becomes the other of the positive and negative poles, and the other catheter electrodes are disconnected; wherein, the ordered array (j1, j2) traverses all situations where j1<j2, the value range of j1 is 1 to M, and the value range of j2 is 1 to M.

[0166] For each different ordered array (j1, j2), the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit, and it is determined whether the equivalent impedance is less than the first short-circuit threshold; if it is less, it is determined that a short-circuit condition exists between the j1-th catheter electrode and the j2-th catheter electrode.

[0167] Another optional solution is to select one electrode as one polarity for impedance detection, and all other electrodes as the other polarity for impedance detection, and detect the impedance between the two polarities:

[0168] 1-(2 to 24)

[0169] (For example, if electrode 1# is used as the positive electrode ZP, then electrodes 2# to 24# are used as the negative electrode ZN, which can be regarded as one electrode; electrodes with the same polarity can be considered as short-circuited with each other, and no further short-circuit detection is required.)

[0170] 2-(3 to 24)

[0171] 3-(4 to 24)

[0172] ……

[0173] 23-24

[0174] This method requires a maximum of 23 impedance detections. If any group is detected to be less than a certain threshold during the detection process, it indicates that the electrodes are short-circuited or the distance between the electrodes is too close, and there is no need to further determine the specific short-circuited electrodes.

[0175] That is, the impedance detection method includes:

[0176] Outputting a control signal to drive each switching element in the switching module to turn on or off, so that the j1th catheter electrode becomes one of the positive and negative electrodes, the j2th to Mth catheter electrodes become the other of the positive and negative electrodes, and the other catheter electrodes are disconnected; wherein the ordered array (j1, j2) traverses all cases where j1 < j2, the value range of j1 is 1 to M, and the value range of j2 is 1 to M.

[0177] For each different ordered array (j1, j2), detect the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, and determine whether the equivalent impedance is less than the second short-circuit threshold; if it is less, determine that at least one of the j1th catheter electrode and the j2th to Mth catheter electrodes has a short circuit condition.

[0178] Subsequently, the above conclusion can be directly adopted as needed, or additional steps can be added to determine the exact short-circuit position.

[0179] The preferred scheme is as follows: In actual use, it is not necessary to detect the impedance between all electrodes. All electrodes can be divided into several segments according to the number of electrodes, and each segment discharges in turn. Therefore, it is only necessary to detect the segment impedance D between the discharging segment and the non-discharging segment, and the comprehensive impedance Z of the positive polarity electrode and the negative polarity electrode in the discharging segment. For example, for a circular pulse ablation catheter with 24 electrodes, every 8 electrodes can be divided into one segment. The 24 electrodes are divided into 3 segments in total, that is: electrodes 1# to 8# are the first segment; electrodes 9# to 16# are the second segment; electrodes 17# to 24# are the third segment. Since a short circuit of electrodes in the non-discharging segment or a short circuit of electrodes of the same polarity in the discharging segment will not cause safety hazards, it is only necessary to perform impedance detection once in each of the following two steps to detect the short circuit condition of the electrodes in the discharging segment.

[0180] In Figure 5 The text includes symbols D1, D2, and D3, each representing a segment impedance D; Z1, Z2, and Z3, each representing a segment's overall impedance Z; and D* and Z*, where D* represents the segment impedance threshold used for judgment, and Z* represents the overall impedance threshold used for judgment. In other words, symbols without "*" represent measured values, while symbols with "*" represent threshold values.

[0181] Step 1: As Figure 5 As shown, the impedance D1 of the discharge and non-discharge sections is detected. Taking section 1 as the discharge section and sections 2 and 3 as the non-discharge sections as an example, electrodes 1# to 8# represent one polarity of impedance detection, for example, connected to the positive impedance detection terminal ZP; electrodes 9# to 24# represent the other polarity of impedance detection, for example, connected to the negative impedance detection terminal ZN. During impedance detection, K311 and K312 are closed to connect to the impedance detection circuit, while K201 and K202 are opened to avoid the influence of the pulse generation circuit on the impedance detection circuit.

[0182] Step 2: As Figure 5 As shown, the combined impedance Z1 of the positive electrode (e.g., connected to the positive DC bus HVP during discharge) and the negative electrode (e.g., connected to the negative DC bus HVN during discharge) within the discharge section is measured. Taking the first section as the discharge section and the second and third sections as the non-discharge sections as an example, electrodes 1#, 3#, 5#, and 7# represent one polarity of impedance detection, such as being connected to the positive impedance detection terminal ZP; electrodes 2#, 4#, 6#, and 8# represent the other polarity of impedance detection, such as being connected to the negative impedance detection terminal ZN. During impedance detection, K311 and K312 are closed to connect the pre-discharge electrode to the impedance detection circuit, while K201, K202, and the non-discharge section electrodes (electrodes 9# to 24#) are disconnected to avoid the influence of the pulse generation circuit and the non-discharge electrodes on the impedance detection circuit.

[0183] If there is no alarm indicating electrode short circuit or electrode too close, the first stage of discharge for the eight electrodes can be initiated: electrodes 1#, 3#, 5#, and 7# are connected to the positive DC bus HVP; electrodes 2#, 4#, 6#, and 8# are connected to the negative DC bus HVN. During pulse discharge, K201 and K202 are closed to connect to the pulse generation circuit, while K311, K312, and the non-discharge section electrodes (electrodes 9# to 24#) are disconnected to prevent high-voltage pulse energy from being introduced into the impedance detection circuit. Additionally, during the first stage of discharge, the second and third stage non-discharge electrodes must also be disconnected to prevent the non-discharge sections from participating in the pulse discharge.

[0184] After the first stage of discharge is completed, the second stage impedance detection D2, the comprehensive impedance detection Z2, and the second stage pulse discharge can be initiated; finally, the third stage impedance detection D3, the comprehensive impedance detection Z3, and the third stage pulse discharge can be initiated. The complete pulse discharge logic is as follows: Figure 5 As shown. The entire discharge process is a 3-stage discharge, requiring only 6 impedance checks. A complete three-dimensional ring ablation lesion can be formed with just one discharge, resulting in high surgical efficiency.

[0185] Figure 6 This graph shows the relationship between impedance and electrode spacing, measured by varying the electrode spacing of the two electrodes in a saline bath environment of approximately 220Ω (calibrated under normal electrode spacing). Based on this graph, 1mm, 2mm, or other spacings can be selected as the alarm threshold for electrodes being too close together. Under this spacing, the inter-electrode impedance alarm threshold between adjacent electrodes is P*.

[0186] Figure 7 This is a 24-electrode annular pulse ablation catheter divided into 3 segments, each with 8 electrodes. The diagram shows the relationship between the average impedance P between adjacent electrodes, the comprehensive impedance Z of the discharge segment, and the impedance D between the discharge and non-discharge segments. According to this diagram, when the impedance between adjacent electrodes is P*, the alarm threshold for the comprehensive impedance of the discharge segment is Z*, and the alarm threshold for the impedance between the discharge and non-discharge segments is D*. If either Z or D exceeds the alarm threshold, the system will not initiate pulse discharge and will alert the user via a display screen or sound indicating an electrode short circuit or excessive proximity.

[0187] Furthermore, to further improve surgical efficiency, the number of segments can be reduced, for example, changing from a three-segment to a two-segment or even a single-segment design. A two-segment design divides electrodes #1 to #12 into one segment and #13 to #24 into another. The short-circuit detection and discharge logic are the same as the three-segment design, requiring only two segments for discharge and four impedance checks. A single-segment design treats all electrodes as a single segment, with only discharge segments and no non-discharge segments. A single-segment design only requires one comprehensive impedance check to determine if there is an electrode short circuit or excessive distance, making it the most efficient. However, the fewer the segments, the more electrodes are connected in parallel, the lower the comprehensive impedance, and the smaller the difference from the comprehensive impedance alarm threshold Z*, the easier it is to falsely trigger a short-circuit alarm. Therefore, single-segment discharge requires higher accuracy from the impedance detection circuit. Additionally, the more electrodes discharged simultaneously... Figure 3 The greater the current on the positive and negative buses HVP and HVN, the greater the stress on the power components or switches (e.g.) Figure 3 The more easily K201 and K202 are damaged, the more likely they are to fail. Therefore, it is necessary to select a suitable discharge and short-circuit protection strategy for the entire pulse ablation system, considering factors such as discharge efficiency, safety, and reliability.

[0188] The single-stage working logic can be summarized as follows: the discharge ablation procedure is performed based on a complete spiral catheter, and the impedance detection methods include:

[0189] Before the ablation process, an output control signal drives each switching element in the switching module to turn on or off, ensuring that the connection state of all conduit electrodes is consistent with the connection state during the upcoming ablation process. "Consistent connection state" means that if a switching element is off during the ablation process, then that switching element is also off at this time, and vice versa.

[0190] Additionally, the equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit. If the equivalent impedance is less than the third short-circuit threshold (i.e., Z*), the discharge ablation operation is terminated; otherwise, it continues.

[0191] The working logic of two-stage and three-stage methods can be summarized as follows: the catheter electrode is set into at least two segments along the spiral catheter, with the electrodes in the same segment being adjacent to each other. Each ablation step in the discharge ablation process is implemented based on one segment of the spiral catheter; impedance detection methods include:

[0192] During the execution of the discharge ablation procedure, the following steps are performed before each discharge ablation step:

[0193] The output control signal drives each switching element in the switching module to turn on or off, making the electrode in the conduit section that is about to be used for discharge ablation one of the positive and negative poles, and making the other conduit electrodes the other of the positive and negative poles.

[0194] The equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit. If the equivalent impedance is less than the fourth short-circuit threshold (i.e., D*), the discharge ablation work is terminated; otherwise, it continues.

[0195] The output control signal drives each switching element in the switching module to turn on or off, making the electrode in the conduit section that is about to be used for discharge ablation one of the positive and negative poles, and making the other conduit electrodes the other of the positive and negative poles.

[0196] The equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit. If the equivalent impedance is less than the fifth short-circuit threshold, the discharge ablation work is terminated; otherwise, it continues.

[0197] The output control signal drives each switching element in the switching module to turn on or off, so that the connection state of all conduit electrodes is consistent with the connection state during the upcoming discharge ablation operation.

[0198] Additionally, the equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit. If the equivalent impedance is less than the fifth short-circuit threshold (i.e., Z*), the discharge ablation operation is terminated; otherwise, it continues.

[0199] This embodiment also provides a pulsed electric field ablation system, which includes a control module and the ablation device described above. The control module is used to perform the impedance detection method described above based on the ablation device.

[0200] The control module is used to determine whether to control the ablation device to perform discharge ablation work based on the information obtained after the impedance detection method is executed.

[0201] The aforementioned pulsed electric field ablation system can also solve the problem of the lack of comprehensive detection methods in existing multi-electrode ablation devices.

[0202] In summary, the ablation device, impedance detection method, and pulsed electric field ablation system provided in this embodiment have the following innovative features:

[0203] 1. A novel switching circuit is proposed, which is shared by the discharge path and the impedance detection path. By switching them alternately, multiple discharge modes and multiple impedance detection methods between multiple electrodes can be realized to determine whether a short circuit has occurred between multiple electrodes.

[0204] 2. A novel short-circuit detection method is proposed, which determines whether a short circuit has occurred or whether the electrodes are too close by judging the impedance between multiple electrodes.

[0205] Furthermore, it is preferred to distinguish between the discharge segment and the non-discharge segment, detect the segment impedance of the discharge segment and the non-discharge segment, and detect the combined impedance of the positive and negative electrodes within the discharge segment to quickly identify electrodes with short-circuit risk.

[0206] 3. Through experiments, a method for determining the alarm threshold of the discharge section and the non-discharge section impedance, as well as the comprehensive impedance of the discharge section, was proposed.

[0207] 4. A pulsed electric field ablation system is proposed, including a novel switching circuit and impedance detection circuit to enable this short-circuit detection method.

[0208] The beneficial effects of this embodiment are as follows:

[0209] 1. It can be configured with multiple discharge modes such as unipolar discharge, bipolar discharge, and multipolar discharge.

[0210] 2. The discharge polarity of the conduit electrode can be configured arbitrarily, and the service life of the switching element can be improved by switching the discharge electrode polarity alternately.

[0211] 3. It can detect various impedance methods, such as unipolar impedance, arbitrary bipolar impedance, comprehensive impedance of discharge section, and impedance of discharge section and non-discharge section.

[0212] 4. It can quickly determine whether the electrodes of the multi-electrode cardiac pulse electric field ablation system are short-circuited or too close together.

[0213] 5. It can perform bonding quality inspection and provide feedback on bonding status.

[0214] The above description is only a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present invention.

Claims

1. An ablation device, characterized in that, The ablation device includes an impedance detection circuit, a pulse ablation circuit, and a catheter; the pulse ablation circuit includes a switching module and at least two catheter electrodes, the switching module is used to control each catheter electrode to independently disconnect, become a positive electrode or become a negative electrode, and the at least two catheter electrodes are arranged sequentially along the catheter to realize a unipolar discharge mode, a bipolar discharge mode, a multi-stage discharge mode, and a discharge form with adjustable discharge polarity of the ablation catheter. The impedance detection circuit is used to detect the equivalent impedance of the pulse ablation circuit before the pulse ablation circuit performs discharge ablation. Specifically, it drives the state of each switching element in the switching module to conform to a preset state by outputting a control signal, thereby achieving unipolar impedance detection, bipolar impedance detection, multi-level impedance detection within the discharge segment, or multi-level impedance detection between the discharge segment and the non-discharge segment. The equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit. Furthermore, the detection result is obtained based on the equivalent impedance, thereby achieving at least one of nominal impedance detection, contact quality detection, and short-circuit detection.

2. The ablation device according to claim 1, characterized in that, The catheter is spiral-shaped.

3. The ablation device according to claim 1, characterized in that, The impedance detection circuit includes an impedance detection module and an impedance detection branch; The impedance detection module is used to detect the equivalent impedance of the circuit connected to it. The impedance detection branch is used to connect the pulse ablation circuit and the impedance detection module, and a compensation resistor is connected in series between the pulse ablation circuit and the impedance detection module.

4. The ablation device according to claim 3, characterized in that, The impedance detection circuit further includes at least one of a calibration branch, a lower limit branch, and an upper limit branch. The calibration branch, the lower limit branch, the upper limit branch, and the impedance detection branch are independently connected to or disconnected from the impedance detection module via switching elements. When the calibration branch is connected to the impedance detection module, it provides a calibration resistor. The impedance detection module configures calibration parameters based on the detected impedance and the pre-stored resistance value of the calibration resistor. When the lower limit branch is connected to the impedance detection module, it provides a lower limit resistor. The impedance detection module obtains the lower limit accuracy based on the detected impedance and the pre-stored resistance value of the lower limit resistor. When the upper limit branch is connected to the impedance detection module, it provides an upper limit resistor. The impedance detection module obtains the upper limit value accuracy based on the detected impedance and the pre-stored resistance value of the upper limit resistor. The lower limit resistor and the upper limit resistor are set based on the range of the equivalent impedance when the ablation device is working normally.

5. An impedance detection method, characterized in that, The impedance detection method is applied to the ablation device as described in any one of claims 1 to 4; The impedance detection method includes: The output control signal drives the state of each switching element in the switching module to conform to the preset state, so as to realize unipolar impedance detection, bipolar impedance detection, multi-level impedance detection in the discharge section or multi-level impedance detection between the discharge section and the non-discharge section. The equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit; and, The detection results are obtained based on the equivalent impedance, thereby achieving at least one of nominal impedance detection, contact quality detection, and short circuit detection.

6. The impedance detection method according to claim 5, characterized in that, The impedance detection circuit further includes an impedance detection module and an impedance detection branch, and before detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, the impedance detection method further comprises the following steps: Outputting a control signal to drive the impedance detection branch to separately connect the pulse ablation circuit, a compensation resistor connected in series between the pulse ablation circuit and the impedance detection module, and the impedance detection module.

7. The impedance detection method according to claim 6, characterized in that, The impedance detection circuit further comprises at least one of a calibration branch, a lower limit branch and an upper limit branch, and before detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, the impedance detection method adaptively further comprises at least one of the following steps according to the specific structure of the impedance detection circuit: Outputting a control signal to drive the calibration branch to be separately connected to the impedance detection module, and the impedance detection module configures calibration parameters; Outputting a control signal to drive the lower limit branch to be separately connected to the impedance detection module, and the impedance detection module acquires lower limit value precision; Judging whether the lower limit value precision meets the working requirement; Outputting a control signal to drive the upper limit branch to be separately connected to the impedance detection module, and the impedance detection module acquires upper limit value precision; and Judging whether the upper limit value precision meets the working requirement.

8. The impedance detection method according to claim 5, characterized in that, The catheter is in a spiral shape, the catheter is arranged as a 1st turn to an N1-th turn from the inside to the outside, N1 is the total number of turns of the catheter, and the impedance detection method comprises: Outputting a control signal to drive each switching element in the switch module to turn on or off, so that the catheter electrode in the i-th turn serves as one of the positive electrode and the negative electrode, the catheter electrode in the (i+1)-th turn serves as the other of the positive electrode and the negative electrode, and the other catheter electrodes are disconnected; wherein the value of i ranges from 1 to N1-2; For each different value of i, detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit; Calculate R 标称 =The sum of the equivalent impedances corresponding to all different values ​​of i ÷ N2, where N2 is the total number of catheter electrodes in turns 1 to N1-1; and, R 标称 Set to the nominal resistance value of the catheter electrode.

9. The impedance detection method according to claim 8, characterized in that, The catheter electrodes are arranged on the catheter as a 1st catheter electrode to an M-th catheter electrode, M is the total number of the catheter electrodes, and the impedance detection method comprises: Outputting a control signal to drive each switching element in the switch module to turn on or off, so that the j-th catheter electrode serves as one of the positive electrode and the negative electrode, the (j+1)-th catheter electrode serves as the other of the positive electrode and the negative electrode, and the other catheter electrodes are disconnected; wherein the value of j ranges from 1 to M-1; For each different value of j, the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit and set as R. j ; If R1>A*R 标称 If the first catheter electrode is properly attached, then it is determined that the first electrode is in good contact with the catheter; if R1≤B*R 标称 If the first catheter electrode is not properly attached, it is determined that the first catheter electrode is properly attached; otherwise, it is determined that the first catheter electrode is properly attached. When j≠1, if R j >A*R 标称 And R j-1 >A*R 标称 Then it is determined that the j-th described catheter electrode is in good contact; if R j ≤B*R 标称 And R j-1 ≤B *R 标称 If the contact is poor, the j-th catheter electrode is determined to be poorly attached; otherwise, the j-th catheter electrode is determined to be generally properly attached. If R M-1 >A*R 标称 If R M-1 ≤B*R 标称 If the Mth catheter electrode is not properly attached, then the Mth catheter electrode is determined to be properly attached; otherwise, the Mth catheter electrode is determined to be properly attached. Wherein A and B are preset parameters, and A>B.

10. The impedance detection method according to claim 5, characterized in that, The catheter electrodes are arranged on the catheter as a 1st catheter electrode to an M-th catheter electrode, M is the total number of the catheter electrodes, and the impedance detection method comprises: Outputting a control signal to drive each switching element in the switch module to turn on or off, so that the j1-th catheter electrode serves as one of the positive electrode and the negative electrode, the j2-th catheter electrode serves as the other of the positive electrode and the negative electrode, and the other catheter electrodes are disconnected; wherein the ordered array (j1, j2) traverses all cases where j1<j2, the value of j1 ranges from 1 to M, and the value of j2 ranges from 1 to M; For each different ordered array (j1, j2), the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit, and it is determined whether the equivalent impedance is less than a first short-circuit threshold; if it is less, it is determined that a short circuit exists between the j1-th catheter electrode and the j2-th catheter electrode.

11. The impedance detection method according to claim 5, characterized in that, The catheter electrodes are arranged along the catheter as the 1st to the M-th catheter electrodes, where M is the total number of the catheter electrodes, and the impedance detection method comprises: outputting a control signal to drive each switching element in the switch module to turn on or off, so that the j1-th catheter electrode serves as one of the positive and negative electrodes, the j2-th to M-th catheter electrodes serve as the other of the positive and negative electrodes, and the other catheter electrodes are disconnected; wherein the ordered array (j1, j2) traverses all cases where j1 < j2, the value range of j1 is 1 to M, and the value range of j2 is 1 to M; For each different ordered array (j1, j2), the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit, and it is determined whether the equivalent impedance is less than a second short-circuit threshold; if it is less, it is determined that at least one short circuit exists between the j1-th catheter electrode and any of the j2-th to M-th catheter electrodes.

12. The impedance detection method according to claim 5, characterized in that, The discharge ablation operation is implemented based on the complete catheter, and the impedance detection method comprises: Before the discharge ablation operation, outputting a control signal to drive each switching element in the switch module to turn on or off, so that the connection state of all the catheter electrodes is consistent with the connection state in the upcoming discharge ablation operation; and detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, determining whether the equivalent impedance is less than a third short-circuit threshold, if it is less, determining to terminate the discharge ablation operation; otherwise, proceeding.

13. The impedance detection method according to claim 5, characterized in that, The catheter electrodes are arranged along the catheter into at least two segments, the catheter electrodes in the same segment are adjacent to each other end to end, and each discharge ablation step in the discharge ablation operation is implemented based on one segment in the catheter; the impedance detection method comprises: During the execution of the discharge ablation operation, before each discharge ablation step, the following steps are performed: outputting a control signal to drive each switching element in the switch module to turn on or off, so that the catheter electrodes in the segment to be used for discharge ablation serve as one of the positive and negative electrodes, and the other catheter electrodes serve as the other of the positive and negative electrodes; detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is less than a third short-circuit threshold, determining to terminate the discharge ablation operation; otherwise, proceeding; outputting a control signal to drive each switching element in the switch module to turn on or off, so that the catheter electrodes in the segment to be used for discharge ablation serve as one of the positive and negative electrodes, and the other catheter electrodes serve as the other of the positive and negative electrodes; detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is less than a fourth short-circuit threshold, determining to terminate the discharge ablation operation; otherwise, proceeding; The output control signal drives each switching element in the switching module to turn on or off, ensuring that the connection state of all the catheter electrodes is consistent with the connection state during the upcoming discharge ablation operation; and... The equivalent impedance of the pulse ablation circuit is detected by the impedance detection circuit. If the equivalent impedance is less than the fifth short-circuit threshold, the discharge ablation operation is terminated; otherwise, it continues.

14. A pulsed electric field ablation system, characterized in that, The pulsed electric field ablation system includes a control module and an ablation device as described in any one of claims 1 to 4, wherein the control module is used to perform the impedance detection method as described in any one of claims 5 to 13 based on the ablation device.

15. The pulsed electric field ablation system according to claim 14, characterized in that, The control module is used to determine whether to control the ablation device to perform discharge ablation work based on the information obtained after the impedance detection method is executed.

Images