Pulse electric field ablation control device

Abstract

The invention relates to the technical field of catheter mapping and ablation, and discloses a pulsed electric field ablation control device. The pulsed electric field ablation control device comprises: an impedance detection part for performing fine impedance detection on a contacted tissue by using an electrode on an ablation catheter; the tissue thickness determining part is used for determining the thickness of the tissue according to the change of the detected impedance under different contact conditions; and the ablation control part is used for controlling the ablation catheter to carry out pulsed electric field ablation output according to the determined thickness of the tissue. According to the focusing electrode, the impedance of the contact tissue and the tiny impedance change under different contact conditions can be accurately detected, so that the tissue thickness can be calculated, proper ablation parameters can be matched, and complications caused by too large ablation parameters are avoided. In addition, according to the pulse electric field ablation control technology, the ablation depth can be determined, and excessive ablation is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of catheter mapping and ablation, and more specifically to a pulse electric field ablation control device. Background Art

[0002] Pulsed electric field technology is a technique that applies a short high voltage to tissues to generate a local high electric field of hundreds of volts per centimeter. The local high electric field destroys the cell membrane by creating pores in the cell membrane. The electric field applied to the membrane is greater than the cell threshold, so the pores are not closed. This electroporation is irreversible, allowing biomolecular materials to pass through the membrane for exchange, leading to cell necrosis or apoptosis. Pulse irreversible electroporation ablation is different from physical therapies based on the principle of thermal ablation, such as radiofrequency, cryotherapy, microwave, and ultrasound. The irreversible electroporation destruction of the myocardial cell membrane by microsecond pulses is a non-thermal biological effect that can effectively avoid damage to blood vessels, nerves, and esophagus. High-frequency pulsed electric fields maintain the non-thermal advantage of irreversible electroporation. Electric field pulses are expected to break through the problem of uneven internal electric field distribution caused by the cell membrane capacitance effect and the anisotropy of biological tissues. In the usage scenario of bipolar pulses, after a positive pulse train ends, a negative pulse train with the same pulse width and equal field strength is applied immediately. It is possible that the action potential induced by the positive pulse has not had time to fully generate, and the negative pulse causes the action potential to develop in the opposite direction, which will greatly reduce the electric field's stimulation of the nerves.

[0003] The pulsed electric field ablation time is extremely short, and the ablation depth cannot be accurately controlled, which has the risk of excessive ablation damage. At the same time, since the tissue thickness at the ablation site varies greatly due to the location of the heart and individual differences, if the ablation parameter is set to a small value, the ablation cannot be thorough. If the ablation parameter is set to a large value, there will be severe muscle tremor reactions and excessive damage to the ablation. Based on the above problems, in order to improve the success rate of pulsed electric field ablation and reduce the complications caused by ablation, a design that can calculate and measure tissue thickness, recommend ablation parameters based on location and tissue thickness, and calculate the ablation depth is needed. Summary of the invention

[0004] From the above description, it can be seen that the current pulse ablation technology has the following problems: 1. The pulse ablation discharge time is short, and multiple superimposed ablations are required to achieve the ideal ablation depth. The depth of pulse ablation damage cannot be clearly grasped.

[0005] 2. There is a lack of effective methods to assess tissue thickness at the ablation site.

[0006] This application designs a pulsed electric field ablation control technology to address the above problems. This technology is based on fine electrophysiological signal mapping and fine impedance detection, and can predict the thickness of the tissue to be ablated, thereby controlling the ablation catheter to output pulsed electric field ablation. The "control" mentioned here includes determining ablation parameters, such as pulse discharge voltage, single effective discharge time, pulse width, number of superpositions, as well as safety monitoring, ablation depth calculation, and starting and stopping the ablation process.

[0007] According to the first aspect of the present application, a pulsed electric field ablation control method is provided. The pulsed electric field ablation control method may include: using electrodes on an ablation catheter to perform fine impedance detection on the contacted tissue; determining the thickness of the tissue according to the change of the detected impedance under different contact conditions; and controlling the ablation catheter to output pulsed electric field ablation according to the determined thickness of the tissue.

[0008] Preferably, the controlling step may further include: determining ablation parameters based on the location of the tissue and the determined thickness of the tissue.

[0009] Preferably, the ablation parameters may include: pulse discharge voltage, single effective discharge time, pulse width, and number of superpositions.

[0010] Preferably, the pulsed electric field ablation control method further comprises: determining the location of the tissue that the electrode is contacting based on the electrophysiological signal collected by the electrode.

[0011] Preferably, the contact condition includes abutment pressure. In the pulsed electric field ablation control method according to the first aspect of the present application, the impedance detection step may include: collecting impedance values ​​for the tissue under different abutment pressure conditions; the tissue thickness determination step may include: comparing the change characteristics of the collected impedance values ​​with the pre-stored impedance value change characteristics of different tissue thicknesses, and matching to obtain the thickness of the tissue.

[0012] Specifically, the acquired impedance value variation characteristics can be drawn as a curve, and the pre-stored impedance value variation characteristics of different tissue thicknesses can be a plurality of basic curves reflecting the impedance value variation characteristics of different tissue thicknesses drawn and saved in advance through experimental data. The step of matching to obtain the thickness of the tissue includes: when the acquired impedance value variation characteristic curve matches one of the plurality of basic curves reflecting the impedance value variation characteristics of different tissue thicknesses drawn and saved in advance through experimental data, the thickness of the tissue is determined as the tissue thickness reflected by the matched basic curve.

[0013] Preferably, the collected impedance value may be the difference between the real-time detected impedance value and the impedance value in the blood.

[0014] During the pulse electric field ablation output process, when a sudden change in real-time impedance is detected, the control step may further include: immediately stopping the pulse electric field ablation output.

[0015] Preferably, the control step may further include: controlling whether the ablation catheter continues to output pulsed electric field ablation according to a comparison result between the real-time ablation depth and the thickness of the tissue.

[0016] Preferably, the pulse electric field ablation control method may further include: during the pulse electric field ablation output process, calculating the real-time ablation depth according to the ablation parameters and the real-time contact pressure.

[0017] The real-time ablation depth can be calculated according to the following formula: , Among them, PFADepth is the real-time ablation depth, V is the pulse discharge voltage, T is the single effective discharge time, u is the pulse width, n is the number of superpositions, CF is the real-time contact pressure, t is the time variable, and C, α, and β are correction coefficients.

[0018] The control step may further include: when the real-time ablation depth is less than the thickness of the tissue, controlling the ablation catheter to continue pulsed electric field ablation output; when the real-time ablation depth is equal to the thickness of the tissue, controlling the ablation catheter to stop ablation.

[0019] Preferably, the pulsed electric field ablation control method may further include: estimating the ablation lesion range in the tissue according to the real-time lesion detection result. Thus, the control step may further include: controlling whether the ablation catheter continues to output pulsed electric field ablation according to the ablation lesion range in the tissue.

[0020] Preferably, the ablation catheter comprises an optical sensor disposed between electrodes, and the ablation lesion estimation step may include: estimating the ablation lesion range in the tissue according to the optical signal detected by the optical sensor.

[0021] Similarly, if the ablation catheter includes an ultrasonic sensor disposed between electrodes, the ablation lesion estimation step may include: estimating the ablation lesion range in the tissue based on the ultrasonic imaging signal detected by the ultrasonic sensor.

[0022] Preferably, the pulsed electric field ablation control method may further include: calculating the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulsed electric field ablation output process. The ablation damage estimation step may further include: correcting the real-time damage detection result and the calculated real-time ablation depth to estimate the ablation damage range in the tissue.

[0023] Preferably, the contact condition may also include the direction and positional relationship of the abutment and the shape of the ablation catheter.

[0024] The electrodes on the ablation catheter may be bipolar electrodes and the distance between electrodes of different polarities is minimized.

[0025] According to the second aspect of the present application, a pulsed electric field ablation control device is provided. The pulsed electric field ablation control device may include: an impedance detection part, which uses electrodes on an ablation catheter to perform fine impedance detection on the contacted tissue; a tissue thickness determination part, which determines the thickness of the tissue according to the change of the detected impedance under different contact conditions; and an ablation control part, which controls the ablation catheter to output pulsed electric field ablation according to the determined thickness of the tissue.

[0026] Preferably, the ablation control section may further include an ablation parameter determination unit for determining an ablation parameter based on the location of the tissue and the determined thickness of the tissue.

[0027] Preferably, the ablation parameters may include: pulse discharge voltage, single effective discharge time, pulse width, and number of superpositions.

[0028] Preferably, the pulsed electric field ablation control device further comprises a tissue site determination section for determining the site of the tissue that the electrode is contacting based on the electrophysiological signal collected by the electrode.

[0029] Preferably, the contact condition includes abutment pressure. In the pulsed electric field ablation control device according to the second aspect of the present application, the impedance detection part can be configured to: collect impedance values ​​for the tissue under different abutment pressure conditions; the tissue thickness determination part can be configured to: compare the change characteristics of the collected impedance values ​​with the pre-stored impedance value change characteristics of different tissue thicknesses, and match them to obtain the thickness of the tissue.

[0030] Specifically, the acquired impedance value variation characteristics can be drawn as a curve, and the pre-stored impedance value variation characteristics of different tissue thicknesses can be a plurality of basic curves reflecting the impedance value variation characteristics of different tissue thicknesses drawn and saved in advance through experimental data. The matching to obtain the thickness of the tissue includes: when the acquired impedance value variation characteristic curve matches one of the plurality of basic curves reflecting the impedance value variation characteristics of different tissue thicknesses drawn and saved in advance through experimental data, the thickness of the tissue is determined as the tissue thickness reflected by the matched basic curve.

[0031] Preferably, the collected impedance value may be the difference between the real-time detected impedance value and the impedance value in the blood.

[0032] During the pulse electric field ablation output process, when the impedance detection part detects a sudden change in real-time impedance, the ablation control part may be further configured to immediately stop the pulse electric field ablation output.

[0033] Preferably, the ablation control section may be further configured to control whether the ablation catheter continues to output pulsed electric field ablation according to a comparison result between the real-time ablation depth and the thickness of the tissue.

[0034] Preferably, the pulse electric field ablation control device may further include an ablation depth determination section, which calculates the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulse electric field ablation output process.

[0035] The ablation depth determination part may calculate the real-time ablation depth according to the following formula: , Among them, PFADepth is the real-time ablation depth, V is the pulse discharge voltage, T is the single effective discharge time, u is the pulse width, n is the number of superpositions, CF is the real-time contact pressure, t is the time variable, and C, α, and β are correction coefficients.

[0036] The ablation control part may be further configured to: when the real-time ablation depth is less than the thickness of the tissue, control the ablation catheter to continue pulsed electric field ablation output; when the real-time ablation depth is equal to the thickness of the tissue, control the ablation catheter to stop ablation.

[0037] Preferably, the pulse electric field ablation control device may further include an ablation lesion estimation part, which estimates the ablation lesion range in the tissue according to the real-time lesion detection result. Thus, the ablation control part may be further configured to: control whether the ablation catheter continues to output pulse electric field ablation according to the ablation lesion range in the tissue.

[0038] Preferably, the ablation catheter comprises an optical sensor disposed between electrodes, and the ablation lesion estimating section may be configured to estimate the ablation lesion range in the tissue according to an optical signal detected by the optical sensor.

[0039] Similarly, the ablation catheter includes an ultrasound sensor disposed between electrodes, and the ablation lesion estimation section may be configured to estimate the ablation lesion range in the tissue based on ultrasound imaging signals detected by the ultrasound sensor.

[0040] Preferably, the pulsed electric field ablation control device may further include an ablation depth determination part, which calculates the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulsed electric field ablation output process. The ablation damage estimation part may be further configured to: mutually correct the real-time damage detection result and the calculated real-time ablation depth to estimate the ablation damage range in the tissue.

[0041] Preferably, the contact condition may also include the direction and positional relationship of the abutment and the shape of the ablation catheter.

[0042] The electrodes on the ablation catheter may be bipolar electrodes and the distance between electrodes of different polarities is minimized.

[0043] According to a third aspect of the present application, a non-transitory computer-readable storage medium is provided for storing a computer program. The computer program includes instructions. When the instructions are executed by a processor of an electronic device, the electronic device implements the pulsed electric field ablation control method as described in the first aspect of the present application.

[0044] According to a fourth aspect of the present application, a pulsed electric field ablation system is provided. The pulsed electric field ablation system may include a pulsed electric field ablation catheter and a controller. The controller is used to execute the pulsed electric field ablation control method as described in the first aspect of the present application according to computer instructions.

[0045] The ablation catheter of the present application uses a focusing electrode, which can accurately detect the impedance of the contact tissue and the slight changes in impedance under different contact conditions. Therefore, the pulsed electric field ablation control technology of the present application can calculate the tissue thickness by accurately detecting the impedance change and match the appropriate ablation parameters to avoid complications caused by excessive ablation parameters. In addition, the pulsed electric field ablation control technology of the present application can determine the method and catheter of the ablation depth to avoid excessive ablation. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present application will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which like elements are numbered in a similar manner, and in which: Figure 1 Schematic diagram of ablation of thick myocardial tissue.

[0047] Figure 2 Schematic diagram of ablation of thin myocardial tissue.

[0048] Figure 3 Schematic diagram of ablation of thick myocardial tissue with sufficient contact pressure.

[0049] Figure 4 This is a schematic diagram of the first type of tip electrode arrangement for a bipolar pulsed electric field ablation catheter.

[0050] Figure 5 This is a schematic diagram of the second tip electrode arrangement of a bipolar pulsed electric field ablation catheter.

[0051] Figure 6 This is a schematic diagram of the third tip electrode arrangement of a bipolar pulsed electric field ablation catheter.

[0052] Figure 7 This is a schematic diagram of the fourth tip electrode arrangement of a bipolar pulsed electric field ablation catheter.

[0053] Figure 8 This is a schematic diagram of tip electrode ablation injury.

[0054] Fig. 9 It is a flow chart of a pulse electric field ablation control method according to an embodiment of the present application.

[0055] Fig.10 is a schematic diagram of the electrode lightly touching the tissue.

[0056] Fig.11 It is a schematic diagram of the electrode contacting the tissue when the pressure increases.

[0057] Fig.12 This is a schematic diagram of the impedance changes corresponding to different contact pressures.

[0058] Fig.13 The results after different ablation times are shown.

[0059] Fig.14 This is a schematic diagram of abnormal impedance mutation during ablation.

[0060] Fig.15 An ablation tip with an optical sensor is shown.

[0061] Fig.16 An ablation tip with an ultrasound sensor is shown.

[0062] Fig.17 An example of the distribution of positioning sensors in an ablation catheter is shown.

[0063] Fig.18 is a schematic diagram of a pressure sensor in an ablation catheter.

[0064] Fig.19 It is a schematic block diagram of a pulsed electric field ablation control device and an ablation catheter according to an embodiment of the present application.

[0065] Reference numerals: 1Ablation electrode 2 Myocardial tissue 221 Thick myocardial tissue 222Thin myocardial tissue 3 Ablation damage range 41 First ablation electrode 42 Second ablation electrode 51 The third ablation electrode 52 Fourth ablation electrode 53 Fifth ablation electrode 54 Sixth ablation electrode 61 First main body head electrode 62 microelectrodes 71 Second main body head electrode 72 Tubular Electrode 8. Normal saline 9 tube body 10. Pressure sensor 11Optical Sensor 12 Ultrasonic Sensor 13 Plant tissue 14 Traction components 15First magnetic positioning sensor 16 Second magnetic positioning sensor 311 The scope of damage after ablation 312 The extent of damage after three ablations 313 Damage range after five ablations 171 Elastomer 172 First strain sensor 173 Second strain sensor 174 Third strain sensor DETAILED DESCRIPTION The technical solution of the present application is further described in detail below through embodiments and in combination with the accompanying drawings, but the present application is not limited to the following embodiments.

[0066] Figure 1 Schematic diagram of ablation of thick myocardial tissue. Figure 2 Schematic diagram of ablation of thin myocardial tissue. Figure 3 Schematic diagram of ablation of thick myocardial tissue with sufficient contact pressure.

[0067] like Figures 1 to 3As shown in , when the ablation electrode 1 is ablated under the same ablation parameter setting, the ablation lesion range 3 is substantially the same; however, Figure 1 The thick myocardial tissue 221 shown is relatively thick and difficult to ablate transmurally; Figure 2 The thin myocardial tissue 222 shown is relatively thin, so it can easily penetrate the wall and damage the surrounding tissue; Figure 1 , Figure 3 When the contact pressure is sufficient, the thick myocardial tissue 221 can also be ablated. Fig.13 The results after different ablation times are shown. Fig.13 As shown in FIG. 1 , under the same parameter conditions, the ablation depth on the plant tissue 13 is shown as a damage range 311 after one ablation, a damage range 312 after three ablations, and a damage range 313 after five ablations. Fig.13 It can be seen that as the number of ablations increases, the ablation depth, that is, the damage range, also increases; therefore, the factors affecting the transmural effect of ablation damage are directly related to the contact pressure, tissue thickness, ablation parameters, and the number of superpositions.

[0068] In the prior art bipolar pulse electric field ablation catheter, the electrodes are an even number and are linearly distributed along the axial direction on the catheter tip. Currently, this design has the problem of being unable to accurately focus on the ablation injury site: the contact position is the head electrode, and the discharge ablation range is the head electrode and the rear electrode area; due to the axial linear arrangement, the rear electrode is usually suspended in the air, and does not contact the tissue during discharge, but discharges and ablates in the blood; in this way, part of the energy will flow into the blood, affecting the efficiency of ablation injury; at the same time, too much ablation in the blood may cause unnecessary damage to the red blood cells of the blood and cause complications such as renal failure.

[0069] To avoid the problem of ablation non-focusing, the ablation electrode design used in this application can be as follows: Figures 4 to 7 shown.

[0070] like Figure 4 As shown, in the first head end electrode arrangement of the bipolar pulse electric field ablation catheter, the first ablation electrode 41 and the second ablation electrode 42 are arranged at the top of the catheter. During discharge ablation, the first ablation electrode 41 and the second ablation electrode 42 form a discharge ablation loop. The first ablation electrode 41 and the second ablation electrode 42 have opposite polarities, and the electrode surface areas of the first ablation electrode 41 and the second ablation electrode 42 are equal. This area is the most direct contact area between the catheter and the tissue, and the ablation energy can be fully applied to the tissue. Figure 8 Figure 1 is a schematic diagram of the tip electrode ablation injury. Figure 8 As shown, the ablation electrode 1 ablates the myocardial tissue 2, the ablation damage range 3 is hemispherical, and the ablation energy is concentrated in the myocardial tissue 2. In addition, Figure 4Also shown are the tube body 9 of the ablation catheter and the pressure sensor 10 inside the tube body, and their related functions will be described in further detail below.

[0071] like Figure 5 As shown, in the second head end electrode arrangement of the bipolar pulse electric field ablation catheter, the third ablation electrode 51, the fourth ablation electrode 52, the fifth ablation electrode 53, and the sixth ablation electrode 54 are evenly and symmetrically distributed along the central axis of the catheter, and the electrode surface areas of the third ablation electrode 51, the fourth ablation electrode 52, the fifth ablation electrode 53, and the sixth ablation electrode 54 are equal, the polarities of the ablation electrodes are opposite to each other, the electrode spacing is 0.1-1mm, and the ablation damage area is concentrated at the catheter head end, achieving focused and precise ablation. In addition, Figure 5 Also shown is the body 9 of the ablation catheter.

[0072] like Figure 6 As shown, in the third head electrode arrangement of the bipolar pulsed electric field ablation catheter, a microelectrode 62 is arranged at the top of the first main head electrode 61, and 3-6 microelectrodes 62 are evenly arranged laterally. When ablation is performed, the first main head electrode 61 and the microelectrode 62 have opposite polarities, the electrode surface area of ​​the first main head electrode 61 is equal to the sum of the electrode surface areas of all microelectrodes 62, the first main head electrode 61 and all microelectrodes 62 are independently insulated from each other, and the minimum spacing is 0.10-1mm. The ablation damage area is concentrated at the catheter tip, achieving focused and precise ablation. In addition, Figure 6 Also shown is the body 9 of the ablation catheter.

[0073] like Figure 7 As shown, in the fourth head end electrode arrangement of the bipolar pulsed electric field ablation catheter, a tubular electrode 72 is arranged inside the second main head electrode 71. When ablation is performed, the surface area of ​​the second main head electrode 71 is less than or equal to the inner surface area of ​​the tubular electrode 72, the second main head electrode 71 and the tubular electrode 72 have opposite polarity, the minimum electrode spacing is 0.10-1.0mm, and the ablation damage area is concentrated at the catheter tip, achieving focused and precise ablation. During ablation, physiological saline 8 is continuously perfused inside the tubular electrode 72, and the second main head electrode 71 in contact directly contacts the tissue, forming a loop with the tubular electrode 72 through the tissue or blood and physiological saline 8. Since the tubular electrode 72 is constantly in contact with only physiological saline 8 inside, the tissue impedance contacted by the second main head electrode 71 can also feedback a precise local impedance value. In addition, Figure 7 Also shown are the tube body 9 of the ablation catheter and the pressure sensor 10 inside the tube body, and their related functions will be described in further detail below.

[0074] Figures 4 to 7 In the electrode arrangement shown, the distances between the electrodes are all micro-spacing, which can accurately measure the electrophysiological signals of the tip contacting the tissue, as well as the local impedance between the tip electrode and the tissue.

[0075] by Figure 4 Taking the shown method as an example, the spacing between the first ablation electrode 41 and the second ablation electrode 42 is 0.40-1.30mm. The smaller the electrode spacing, the better the quality of the collected electrophysiological signal, and the more accurate the determination of the tissue location by the electrophysiological signal. Since the electrode tip is in direct contact with the tissue, the electrode tip can directly collect the impedance of the first ablation electrode 41 and the second ablation electrode 42, and the collected impedance value is accurate, avoiding the problem of inaccurate measurement caused by the rear-end electrode hanging in the blood when the traditional front-end electrode collects the impedance of the rear-end electrode. Based on precise electrophysiological signal mapping and precise impedance monitoring, tissue location determination and tissue thickness prediction are performed to give matching ablation parameters. The ablation depth can be calculated after the contact pressure, ablation parameters, and the number of superpositions are known.

[0076] The present application proposes a pulse electric field ablation control method and device. The following describes the specific embodiments of the present application from the perspectives of the method and the device.

[0077] Control Methods As described above, based on precise electrophysiological signal mapping and fine impedance monitoring, the tissue site to be ablated can be determined and the tissue thickness can be predicted, thereby controlling the ablation catheter to output pulsed electric field ablation. The "control" described in this application includes determining ablation parameters, such as pulse discharge voltage, single effective discharge time, pulse width, number of superpositions, as well as safety monitoring, ablation depth calculation, and starting and stopping the ablation process.

[0078] Fig. 9 It is a flow chart of a pulse electric field ablation control method according to an embodiment of the present application.

[0079] like Fig. 9 As shown, the pulse electric field ablation control method 900 according to the embodiment of the present application starts at step S910, in which the electrodes on the ablation catheter are used to perform fine impedance detection on the contacted tissue.

[0080] In step S920, the thickness of the tissue is determined according to the change of the detected impedance under different contact conditions.

[0081] The contact described here may also be referred to as abutment. Those skilled in the art should understand that in the context of the present application, these two terms can be used interchangeably to express the same meaning. The contact condition in step S920 may include the abutment pressure as described above. In a preferred embodiment, step S910 may specifically include: collecting impedance values ​​for the tissue under different abutment pressure conditions. Accordingly, step S920 may specifically include: comparing the change characteristics of the collected impedance values ​​with the pre-stored impedance value change characteristics of different tissue thicknesses, and matching to obtain the thickness of the tissue. Specifically, the change characteristics of the collected impedance values ​​can be drawn as a curve. The pre-stored impedance value change characteristics of different tissue thicknesses can be a plurality of basic curves reflecting the impedance value change characteristics of different tissue thicknesses that are pre-drawn and saved through experimental data. In other words, in the pre-stored basic curves, each curve represents a tissue thickness. The matching described above to obtain the thickness of the tissue is specifically implemented as follows: when the acquired impedance value change characteristic curve matches one of the multiple basic curves reflecting the impedance value change characteristics of different tissue thicknesses drawn and saved in advance through experimental data, the thickness of the tissue is determined as the tissue thickness reflected by the matched basic curve. In a preferred embodiment, the acquired impedance value described here is actually the difference between the real-time detection impedance value and the impedance value in the blood.

[0082] Those skilled in the art should understand that, in some embodiments, the contact condition described herein may also include the direction and positional relationship of the abutment and the shape of the ablation catheter.

[0083] In step S930, the ablation catheter is controlled to output pulsed electric field ablation according to the determined thickness of the tissue.

[0084] The controlling described in step S930 may further include determining ablation parameters.

[0085] According to a preferred embodiment of the present application, the determination of the ablation parameters needs to be based on the determination of the location of the tissue to be ablated and the determination of the thickness of the tissue. Therefore, in addition to step S920, the control method 900 may also need to include an additional step, namely, determining the location of the tissue that the electrode is contacting based on the electrophysiological signal collected by the electrode of the ablation catheter.

[0086] Here, the ablation parameters may include: pulse discharge voltage, single effective discharge time, pulse width, and number of superpositions. Of course, the ablation parameters may also be single ablation parameters in a narrow sense, that is, they do not include the number of superpositions, but only include parameters of a single ablation, such as pulse discharge voltage, single effective discharge time, pulse width, etc.

[0087] During the pulse electric field ablation output process, when a sudden change in real-time impedance is detected, step S930 may further include: immediately stopping the pulse electric field ablation output to ensure the safety of ablation.

[0088] In addition, as mentioned above, the "control" described in step S930 also includes the calculation of the ablation depth. Specifically, in a preferred embodiment, during the pulse electric field ablation output process, the real-time ablation depth is calculated based on the ablation parameters (including pulse discharge voltage, single effective discharge time, pulse width, number of superpositions, etc.) and the real-time contact pressure. More detailed examples are given in the embodiments below.

[0089] Then, according to the comparison result between the real-time ablation depth and the thickness of the tissue, the ablation catheter can be controlled to continue to output pulsed electric field ablation. Specifically, when the real-time ablation depth is less than the thickness of the tissue, the ablation catheter is controlled to continue to output pulsed electric field ablation. When the real-time ablation depth is equal to the thickness of the tissue, the ablation catheter is controlled to stop ablation.

[0090] As mentioned above, the "control" in step S930 also includes safety monitoring. Specifically, the ablation damage range in the tissue can be estimated based on the real-time damage detection result.

[0091] For example, the ablation catheter may include an optical sensor disposed between the electrodes. Based on the light signal detected by the optical sensor, the ablation lesion range in the tissue may be estimated.

[0092] Alternatively, the ablation catheter may include an ultrasound sensor disposed between the electrodes, and the ablation lesion range in the tissue is estimated based on ultrasound imaging signals detected by the ultrasound sensor.

[0093] The above-mentioned real-time damage detection results, whether from optical sensors or ultrasonic sensors, can be mutually corrected with the calculated real-time ablation depth, so as to more accurately estimate the ablation damage range in the tissue. As mentioned above, during the pulsed electric field ablation output process, the real-time ablation depth can be calculated based on the ablation parameters and the real-time contact pressure.

[0094] Furthermore, the ablation catheter is controlled to determine whether to continue to output pulsed electric field ablation according to the ablation damage range in the tissue.

[0095] As mentioned above, since the method of the present application is based on accurate detection of tissue impedance, the arrangement of the concentrated electrodes recommended by the present application has been given above, see Figures 4 to 7 Generally speaking, the electrodes on the ablation catheter may be bipolar electrodes and the distance between electrodes of different polarities needs to be minimized.

[0096] Implementation 1 - Determination of tissue location The approximate position of the electrode can be determined by electrophysiological signal detection. If the electrophysiological signal collected by the electrode only has atrial waveforms, it proves that it is in the atrium; if the collected electrophysiological signal only has ventricular waveforms, it proves that it is in the ventricle; if the collected waveforms have both atrial waveforms and ventricular waveforms, then look at the amplitude of the atrial waveform and the ventricular waveform: if the amplitudes are consistent, it is judged to be located at the tricuspid valve ring or mitral valve ring; if the atrial amplitude is large and the ventricular amplitude is small, it is judged to be near the valve ring and eccentric to the atrial side; if the atrial amplitude is small and the ventricular amplitude is large, it is judged to be near the heart valve ring and eccentric to the ventricular side. The location of the catheter can be basically determined based on the characteristics of the electrophysiological signal. Because the atrial wall is thinner and the ventricular wall is thicker, and ablation in the atrium is more likely to cause muscle tremors, different parameters are selected in different parts.

[0097] Implementation 2 - Determination of tissue thickness like Fig.10 As shown, when the first ablation electrode 41 and the second ablation electrode 42 slightly contact the myocardial tissue 2, that is, when the contact pressure is small, the contact area between the electrode and the tissue is small, and the electrode is mostly in contact with the blood. Because the impedance of the tissue is higher than that of the blood, the impedance value collected by the electrode is relatively small at this time.

[0098] like Fig.11 As shown, when the pressure of the first ablation electrode 41 and the second ablation electrode 42 contacting the myocardial tissue 2 increases, that is, when the contact pressure increases, the contact area between the electrode and the tissue increases, and the contact area between the electrode and the blood decreases. Because the impedance of the tissue is higher than that of the blood, the impedance value collected by the electrode at this time increases relatively greatly.

[0099] Fig.12 This is a schematic diagram of the impedance changes corresponding to different contact pressures. Fig.12 As shown in , based on the above impedance detection characteristics, for the same tissue under different pressure conditions, the electrode collected impedance value △R (△R is the difference between the real-time impedance value and the impedance value in the blood) will increase accordingly, and this characteristic is plotted as a curve, namely the T1, T2 or T3 curve in the figure. For different myocardial tissues, such as atria and ventricles, the change curves will be different, so the tissue thickness represented by T1, T2, and T3 increases in turn. For example, Fig.12As shown in the example, curves T1 to T3 are three basic curves that are pre-drawn and saved through experimental data, reflecting the impedance value change characteristics of three different tissue thicknesses. In other words, each curve in the pre-stored basic curves represents a tissue thickness. In clinical practice, the △R and pressure F change curves are detected (drawn according to the detection results) through the contact between the electrode and the tissue, and the detected curves are matched with the basic curves to calculate the tissue thickness. In other words, when the detected curve matches one of the multiple basic curves that reflect the impedance value change characteristics of different tissue thicknesses that are pre-drawn and saved through experimental data, the thickness of the tissue is determined as the tissue thickness reflected by the matched basic curve.

[0100] Implementation 3 - Selection of ablation parameters The tissue site determined in the first embodiment and the tissue thickness determined in the second embodiment are combined to determine the ablation parameters.

[0101] In a preferred embodiment, the ablation parameters can be expressed as:

[0102] Wherein, V is the pulse discharge voltage, T is the single effective discharge time, u is the pulse width, and n is the number of superpositions. That is, in this preferred embodiment, the ablation parameters include the pulse discharge voltage, the single effective discharge time, the pulse width, and the number of superpositions.

[0103] Implementation 4 - Security Monitoring Safety monitoring can be performed during the ablation process. Since the electrode detection impedance is very delicate and sensitive, such as Fig.14 As shown in , if the local impedance between the detection electrodes suddenly increases during the discharge process, that is, a sudden impedance change occurs, it means that larger microbubbles are generated, and the feedback control system immediately stops ablation.

[0104] Implementation 5 - Calculating real-time ablation depth During the pulsed electric field ablation output process, the real-time ablation depth is calculated based on the ablation parameters and the real-time contact pressure.

[0105] The real-time ablation depth can be calculated according to the following formula: , Among them, PFADepth is the real-time ablation depth, V is the pulse discharge voltage, T is the single effective discharge time, u is the pulse width, n is the number of superpositions, CF is the real-time contact pressure, t is the time variable, and C, α, and β are correction coefficients.

[0106] Implementation 6 - Stop Ablation During the ablation process, the ablation depth is calculated in real time and compared with the tissue thickness collected before ablation. If the real-time ablation depth is less than the tissue thickness, ablation is continued until the ablation depth reaches the tissue thickness.

[0107] More generally, the decision of whether to stop ablation is based on the current lesion assessment. That is, if the current lesion assessment shows that the lesion range has reached the target, for example, the lesion range has reached the tissue thickness in at least one dimension (i.e., the ablation depth), then ablation can be stopped. On the contrary, if the current lesion assessment shows that the lesion range has not reached the target, for example, the lesion range has not penetrated the tissue thickness, then ablation can continue.

[0108] Damage assessments can also be obtained in the following ways.

[0109] Fig.15 An ablation tip with an optical sensor is shown. Fig.15 As shown, the optical sensor 11 is arranged between the first ablation electrode 41 and the second ablation electrode 42, and the real-time damage depth of the ablated tissue can be detected. The detection principle is: light is scattered inside the tissue, and the internal tissue structure analysis is based on the principle of coherent light interferometry. In the low-coherence light interferometry method, the light is separated and transmitted in two directions, and the light reflected or scattered from the target along one path is combined or interfered with the reflected light from another known reference path. This interference signal is collected in the photodetector, analyzed to determine the tissue structure, and then distinguish between the damage and non-damage ranges. The optically detected ablation damage range can be mutually corrected with the ablation depth calculated in Implementation 5, making the damage assessment more accurate and comprehensive.

[0110] Fig.16 An ablation tip with an ultrasound sensor is shown. Fig.16 As shown, the ultrasonic sensor 12 is arranged between the first ablation electrode 41 and the second ablation electrode 42, and the real-time damage depth of the ablated tissue can be detected. The principle of ultrasonic imaging is that different echoes generated by the acoustic impedance and attenuation differences of different tissues constitute an image. By image comparison, the boundary between damaged tissue and normal tissue is distinguished, and then the damage depth range is determined. The ultrasonic detection of the ablation damage range can be mutually corrected with the ablation depth calculated in Implementation 5, making the damage assessment more accurate and comprehensive.

[0111] Implementation 7 - Contact (sticking) situation According to the conception of the present application, the contact condition includes not only the abutment pressure, but also the abutment direction and position relationship and the shape of the ablation catheter. These contact conditions can be measured or evaluated by means of positioning sensors, pressure sensors, etc.

[0112] Fig.17An example of the distribution of positioning sensors in an ablation catheter is shown. Fig.17 As shown, a traction member 14 is provided at the end of the catheter. One end of the entire traction device is provided at the catheter head end, and the other end is provided at the proximal handle assembly. As a component of the traction device, the traction member 14 is provided on the inner side of the catheter bending direction. The traction member 14 is provided away from the catheter axis. The catheter bending plane is perpendicular to the line connecting the electrodes, that is, the center between the two electrodes is the bending direction point, which is used to indicate the bending direction. The first magnetic positioning sensor 15 and the second magnetic positioning sensor 16 are respectively provided at the distal end and the proximal end of the distal tube body, and are used to calculate and display the bending shape of the distal tube body. The first magnetic positioning sensor 15 is composed of two magnetic positioning sensors and forms a certain angle, the angle is 5-20°, which is used to cooperate with the pressure sensor to feedback the catheter abutment direction.

[0113] Fig.18 Figure 1 is a schematic diagram of a pressure sensor in an ablation catheter. When the catheter tip contacts tissue, it is necessary to determine the position and direction of contact between the catheter tip and tissue. Fig.18 As shown in the figure above, a pressure sensor 10 is arranged inside the catheter tip. Fig.18 As shown in the figure below, the pressure sensor 10 includes an elastomer 171 and a first strain sensor 172, a second strain sensor 173, and a third strain sensor 174 symmetrically arranged on the elastomer 171. Preferably, the number of strain sensors is greater than or equal to 3. Preferably, three strain sensors are arranged, and the angle between the strain sensors is 120°, and the zero point position (the center point between the electrodes) is aligned with the first strain sensor 172. This method links the abutment position determined by the pressure sensor with the positional relationship determined by the magnetic positioning sensor. The X-axial force component Fx, the Y-axial force component Fy, and the Z-axial force component Fz are all pre-calibrated data and known data, and the relationship between Fx, Fy, and Fz relative to the zero point position is known. The angle between the lateral force component (F side) and Fx is ∠b, which can be calculated. . Then, since the relationship between Fx and the zero point position is known, the angle relationship of the ∠b zero point position can be calculated. Through ∠a = arctan(Fz / Fside), the direction of the resultant force (Ftotal) and the angle between the lateral force can be determined, and the relationship between the direction of the resultant force and the zero point position can be indirectly calculated. Through the calculated ∠a and ∠b, the direction of contact between the catheter and the tissue (relative to the zero point position) can be determined. The positional relationship between the zero point position and the adjustable bend of the tube body can be known from the above. The direction and positional relationship between the catheter tip and the tissue and the shape of the catheter can be determined comprehensively.

[0114] Controls Fig.19 It is a schematic block diagram of a pulsed electric field ablation control device and an ablation catheter according to an embodiment of the present application.

[0115] like Fig.19As shown in FIG. 1 , the pulse electric field ablation control device 1900 according to the embodiment of the present application includes an impedance detection part 1910, a tissue thickness determination part 1920 and an ablation control part 1930. Those skilled in the art should understand that the impedance detection part 1910, the tissue thickness determination part 1920 and the ablation control part 1930 can respectively perform the same Fig. 9 Operations corresponding to steps S910, S920 and S930 in method 900.

[0116] Specifically, the impedance detection section 1910 uses the electrodes on the ablation catheter to perform fine impedance detection on the contacted tissue. Fig.19 The arrow from the ablation catheter to the impedance detection part 1910 in the figure may indicate that the electrophysiological signal measured by the catheter through the electrode is sent to the impedance detection part 1910 for fine impedance detection. The tissue thickness determination part 1920 determines the thickness of the tissue according to the change of the impedance detected by the impedance detection part 1910 under different contact conditions. The ablation control part 1930 controls the ablation catheter to output pulsed electric field ablation according to the thickness of the tissue determined by the tissue thickness determination part 1920. Fig.19 The arrow from the ablation control part 1930 to the ablation catheter may indicate that the ablation control part 1930 controls the ablation output of the ablation catheter.

[0117] The ablation control part 1930 may further include an ablation parameter determination unit (not shown) for determining ablation parameters based on the location of the tissue and the determined thickness of the tissue. Here, the ablation parameters may include: pulse discharge voltage, single effective discharge time, pulse width, and number of superpositions. In a preferred embodiment, the pulse electric field ablation control device 1900 may further include a tissue location determination part (not shown) for determining the location of the tissue that the electrode is contacting based on the electrophysiological signal collected by the electrode.

[0118] The contact between the catheter (more specifically, the electrode on the catheter) and the tissue can be characterized by the contact pressure. The impedance detection part 1910 can collect impedance values ​​for the tissue under different contact pressure conditions. Accordingly, the tissue thickness determination part 1920 can compare the change characteristics of the collected impedance value with the pre-stored impedance value change characteristics of different tissue thicknesses, and match them to obtain the thickness of the tissue. Specifically, the change characteristics of the collected impedance value are drawn as a curve, and the pre-stored impedance value change characteristics of different tissue thicknesses are multiple basic curves reflecting the impedance value change characteristics of different tissue thicknesses that are drawn and saved in advance through experimental data. When the change characteristic curve of the collected impedance value matches one of the multiple basic curves reflecting the impedance value change characteristics of different tissue thicknesses that are drawn and saved in advance through experimental data, the thickness of the tissue is determined as the tissue thickness reflected by the matched basic curve. Preferably, the collected impedance value is the difference between the real-time detection impedance value and the impedance value in the blood.

[0119] During the pulse electric field ablation output process, when the impedance detection part 1910 detects a sudden change in real-time impedance, the ablation control part 1930 can also immediately stop the pulse electric field ablation output.

[0120] The ablation control part 1930 can also control whether the ablation catheter continues to output pulsed electric field ablation according to the comparison result of the real-time ablation depth and the tissue thickness. For example, the pulsed electric field ablation control device 1900 can further include an ablation depth determination part (not shown) for calculating the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulsed electric field ablation output process. In a preferred embodiment, the ablation depth determination part calculates the real-time ablation depth according to the following formula: , Among them, PFADepth is the real-time ablation depth, V is the pulse discharge voltage, T is the single effective discharge time, u is the pulse width, n is the number of superpositions, CF is the real-time contact pressure, t is the time variable, and C, α, and β are correction coefficients.

[0121] The ablation control part 1930 can control the ablation catheter to continue to output pulsed electric field ablation when the real-time ablation depth is less than the tissue thickness, and control the ablation catheter to stop ablation when the real-time ablation depth is equal to the tissue thickness.

[0122] The pulse electric field ablation control device may also include an ablation lesion estimation section (not shown) for estimating the ablation lesion range in the tissue according to the real-time lesion detection result. In this case, the ablation control section 1930 may control whether the ablation catheter continues to output pulse electric field ablation according to the ablation lesion range in the tissue.

[0123] Specifically, the ablation catheter includes an optical sensor disposed between the electrodes. The ablation lesion estimation section can estimate the ablation lesion range in the tissue based on the optical signal detected by the optical sensor. Alternatively, the ablation catheter includes an ultrasonic sensor disposed between the electrodes. The ablation lesion estimation section can estimate the ablation lesion range in the tissue based on the ultrasonic imaging signal detected by the ultrasonic sensor.

[0124] In this case, the pulsed electric field ablation control device may further include an ablation depth determination part (not shown) for calculating the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulsed electric field ablation output process. The ablation damage estimation part may also mutually correct the real-time damage detection result and the calculated real-time ablation depth to estimate the ablation damage range in the tissue.

[0125] The contact between the catheter (more specifically, the electrodes on the catheter) and the tissue can also be characterized by the direction and position relationship of the contact and the shape of the ablation catheter.

[0126] The electrodes on the ablation catheter illustrated here are bipolar electrodes. The distance between electrodes of different polarities is minimized. For example, Figures 4 to 7 In the electrode arrangement shown, the distances between the electrodes are all micro-spacing, which can accurately measure the electrophysiological signals of the tip contacting the tissue, as well as the local impedance between the tip electrode and the tissue.

[0127] Those skilled in the art should understand that the various parts and units included in the pulsed electric field ablation control device according to the embodiment of the present application can be regarded as functional modules, which can be implemented separately or as a whole through computer software, programs, and instructions, and are not necessarily composed of various physical hardware combined through physical or mechanical connections.

[0128] Those skilled in the art should recognize that the methods involved in the present application can be implemented as computer programs. As described above in conjunction with the accompanying drawings, the methods of the above embodiments are performed by one or more programs, including instructions to enable a computer or processor to perform the algorithms described in conjunction with the accompanying drawings. These programs can be stored and provided to a computer or processor using various types of non-transient computer-readable media. Non-transient computer-readable media include various types of tangible storage media. Examples of non-transient computer-readable media include magnetic recording media (such as floppy disks, tapes, and hard disk drives), magneto-optical recording media (such as magneto-optical disks), CD-ROMs (compact disk read-only memories), CD-Rs, CD-R / Ws, and semiconductor memories (such as ROMs, PROMs (programmable ROMs), EPROMs (erasable PROMs), flash ROMs, and RAMs (random access memories)). Further, these programs can be provided to a computer using various types of transient computer-readable media. Examples of transient computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transient computer-readable media can be used to provide programs to a computer via a wired communication path or a wireless communication path such as wires and optical fibers.

[0129] For example, according to one embodiment of the present application, a non-transitory computer-readable storage medium may be proposed, on which a computer program is stored. The computer program includes instructions, which, when executed by a processor of an electronic device, enable the electronic device to implement the pulsed electric field ablation control method as described above.

[0130] For example, according to one embodiment of the present application, a computer device may be proposed, the computer device comprising a processor, a memory and a computer program. The computer program is stored in the memory and configured to be executed by the processor. The computer program comprises instructions for implementing the pulsed electric field ablation control method as described above.

[0131] A computer program or computing device can be combined with a pulsed electric field ablation consumable to provide a pulsed electric field ablation system. The pulsed electric field ablation system may include a pulsed electric field ablation catheter and a controller. The controller is used to execute the pulsed electric field ablation control method as described above or realize the functions of various parts of the pulsed electric field ablation control device as described above according to computer instructions.

[0132] The implementation methods of the present application are not limited to the above-mentioned embodiments. Without departing from the spirit and scope of the present application, ordinary technicians in this field can make various changes and improvements to the present application in form and details, and these are considered to fall within the scope of protection of the present application.

Claims

1. A pulse electric field ablation control device, characterized in that: The device comprises: The impedance detection part uses the electrodes on the ablation catheter to perform fine impedance detection on the contacted tissue; A tissue thickness determination part, which determines the thickness of the tissue according to the change of the detected impedance under different contact conditions; A tissue site determination section, which determines the site of the tissue that the electrode is contacting based on the electrophysiological signal collected by the electrode; The ablation control part controls the ablation catheter to output pulse electric field ablation according to the location of the tissue and the determined thickness of the tissue.

2. The device according to claim 1, characterized in that The ablation control section further includes an ablation parameter determination unit that determines an ablation parameter based on the location of the tissue and the determined thickness of the tissue.

3. The device according to claim 2, characterized in that The ablation parameters include: pulse discharge voltage, single effective discharge time, pulse width, and superposition times.

4. The device according to claim 1, characterized in that The contact condition includes abutment pressure, wherein the impedance detection part is configured to collect impedance values ​​for the tissue under different abutment pressure conditions, and the tissue thickness determination part is configured to compare the change characteristics of the collected impedance values ​​with the pre-stored impedance value change characteristics of different tissue thicknesses, and match them to obtain the thickness of the tissue.

5. The device according to claim 4, characterized in that The acquired impedance value variation characteristics are plotted as curves, and the pre-stored impedance value variation characteristics of different tissue thicknesses are multiple basic curves reflecting the impedance value variation characteristics of different tissue thicknesses that are pre-drawn and saved through experimental data. The matching to obtain the thickness of the tissue includes: when the acquired impedance value change characteristic curve matches one of a plurality of basic curves that are pre-drawn and saved based on experimental data and reflect the impedance value change characteristics of different tissue thicknesses, the thickness of the tissue is determined as the tissue thickness reflected by the matched basic curve.

6. The device according to claim 4, characterized in that The collected impedance value is the difference between the real-time detected impedance value and the impedance value in the blood.

7. The device according to claim 1, characterized in that During the pulse electric field ablation output process, when the impedance detection part detects a sudden change in real-time impedance, the ablation control part is further configured to immediately stop the pulse electric field ablation output.

8. The device according to claim 1, characterized in that The ablation control section is further configured to control whether the ablation catheter continues to output pulsed electric field ablation according to a comparison result between the real-time ablation depth and the thickness of the tissue.

9. The device according to claim 8, characterized in that The device further comprises an ablation depth determination part, which calculates the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulse electric field ablation output process.

10. The device according to claim 9, characterized in that The ablation depth determination part calculates the real-time ablation depth according to the following formula: ， Among them, PFADepth is the real-time ablation depth, V is the pulse discharge voltage, T is the single effective discharge time, u is the pulse width, n is the number of superpositions, CF is the real-time contact pressure, t is the time variable, and C, α, and β are correction coefficients.

11. The device according to claim 8, characterized in that The ablation control part is further configured to: when the real-time ablation depth is less than the thickness of the tissue, control the ablation catheter to continue pulsed electric field ablation output; when the real-time ablation depth is equal to the thickness of the tissue, control the ablation catheter to stop ablation.

12. The device according to claim 1, characterized in that The device further comprises an ablation lesion estimation section, which estimates the ablation lesion range in the tissue according to the real-time lesion detection result. The ablation control section is further configured to control whether the ablation catheter continues to output pulsed electric field ablation according to the ablation lesion range in the tissue.

13. The device according to claim 12, characterized in that The ablation catheter includes an optical sensor disposed between electrodes, and the ablation lesion estimation section is configured to estimate an ablation lesion range in the tissue according to an optical signal detected by the optical sensor.

14. The device according to claim 12, characterized in that The ablation catheter includes an ultrasonic sensor disposed between electrodes, and the ablation lesion estimation section is configured to estimate an ablation lesion range in the tissue according to an ultrasonic imaging signal detected by the ultrasonic sensor.

15. The device according to claim 12, characterized in that The device further includes an ablation depth determination part, which calculates the real-time ablation depth according to the ablation parameters and the real-time contact pressure during the pulse electric field ablation output process. The ablation damage estimation part is further configured to: correct the real-time damage detection result and the calculated real-time ablation depth to estimate the ablation damage range in the tissue.

16. The device according to claim 1, characterized in that The contact condition includes the direction and position relationship of the abutment and the shape of the ablation catheter.

17. The device according to claim 1, characterized in that The electrodes on the ablation catheter are bipolar electrodes and the distance between electrodes of different polarities is minimized.

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