CN119564326B

CN119564326B - Pulsed electric field ablation control device

Info

Publication number: CN119564326B
Application number: CN202510142752.XA
Authority: CN
Inventors: 朱晓林; 史天才
Original assignee: Sichuan Jinjiang Electronic Medical Device Technology Co ltd
Current assignee: Sichuan Jinjiang Electronic Medical Device Technology Co ltd
Priority date: 2025-02-10
Filing date: 2025-02-10
Publication date: 2025-06-10
Anticipated expiration: 2045-02-10
Also published as: CN119564326A

Abstract

The present application relates to the field of catheter mapping and ablation technology, and discloses a pulsed electric field ablation control device. The pulsed electric field ablation control device includes: an impedance detection part, which 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 changes in the detected impedance under different contact conditions; an ablation control part, which controls the ablation catheter to output pulsed electric field ablation according to the determined thickness of the tissue. The focusing electrode of the present application can accurately detect the impedance of the contacted tissue and the slight changes in impedance under different contact conditions, thereby calculating the tissue thickness and matching 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 for ablation depth to avoid excessive ablation.

Description

Pulse electric field ablation control device

Technical Field

The application relates to the technical field of catheter mapping and ablation, in particular to a pulse electric field ablation control device.

Background

Pulsed electric field techniques are techniques in which a brief high voltage is applied to tissue to generate a localized high electric field of hundreds of volts per centimeter that disrupts the cell membrane by creating pores in the cell membrane. The application of an electric field at the membrane that is greater than the cellular threshold leaves the pores unclosed, such electroporation is irreversible, thereby allowing the exchange of biomolecular material across the membrane, resulting in cell necrosis or apoptosis. Pulse irreversible electroporation ablation is different from physiotherapy based on a thermal ablation principle such as radio frequency, freezing, microwaves and ultrasound, and microsecond pulse irreversible electroporation damage to a myocardial envelope is a non-thermal biological effect and can effectively avoid damage to blood vessels, nerves and esophagus. The electric field pulse with high frequency and irreversible electroporation non-thermal advantage is expected to break through the problem of nonuniform internal electric field distribution caused by cell membrane capacitance effect and biological tissue anisotropy. In the use scene of bipolar pulse, after one positive pulse train is finished, one negative pulse train with the same pulse width and equal field intensity is applied, so that action potential induced by positive pulse is not generated sufficiently, the action potential is developed in the opposite direction due to negative pulse, and the nerve stimulation caused by electric field is greatly reduced.

The pulse electric field ablation time is extremely short, the ablation depth cannot be accurately controlled, the risk of excessive ablation damage exists, meanwhile, the tissue thickness of the ablation part is greatly different due to heart parts and individual differences, if the ablation parameter selection setting is smaller, the ablation cannot be thoroughly performed, and if the ablation parameter selection setting is larger, serious myofibrillation reaction and excessive damage ablation exist. Based on the above problems, in order to improve the success rate of pulsed electric field ablation and reduce complications caused by ablation, a design is needed that can calculate and measure the tissue thickness, recommend ablation parameters for the part and the tissue thickness, and calculate the ablation depth.

Disclosure of Invention

As can be seen from the above description, the current pulse ablation technique has the following problems:

1. the pulse ablation discharge time is short, and the ideal ablation depth is achieved by repeated ablation, so that the depth of pulse ablation damage cannot be clearly mastered.

2. There is a lack of ways to effectively assess tissue thickness at the ablation site.

The application designs a pulsed electric field ablation control technology aiming at the problems. The technology is based on fine electrophysiological signal mapping and fine impedance detection, and can predict the thickness of the tissue to be ablated, so as to control the ablation catheter to perform pulsed electric field ablation output. The term "control" as used herein includes determining ablation parameters such as pulse discharge voltage, single effective discharge time, pulse width, number of stacks, as well as safety monitoring, ablation depth calculation, start and stop of ablation procedures, etc.

According to a first aspect of the present application, a pulsed electric field ablation control method is provided. The pulse electric field ablation control method can comprise the steps of detecting fine impedance of contacted tissues by using electrodes on an ablation catheter, determining the thickness of the tissues according to the detected impedance change under different contact conditions, and controlling the ablation catheter to perform pulse electric field ablation output according to the determined thickness of the tissues.

Preferably, the controlling step may further comprise determining an ablation parameter based on the location of the tissue and the determined thickness of the tissue.

Preferably, the ablation parameters may include pulse discharge voltage, single effective discharge time, pulse width, number of stacks.

Preferably, the pulsed electric field ablation control method further comprises determining a location of the tissue with which the electrode is contacting based on electrophysiological signals acquired by the electrode.

Preferably, the contact condition comprises an 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 acquiring impedance values for the tissue under different conditions of abutment pressure, and the tissue thickness determination step may include comparing the acquired variation characteristics of the impedance values with pre-stored variation characteristics of the impedance values of different tissue thicknesses, and matching to obtain the thickness of the tissue.

Specifically, the acquired characteristic of the change in the impedance value may be plotted as a curve, and the prestored characteristic of the change in the impedance value of the different tissue thicknesses may be a plurality of base curves reflecting the characteristic of the change in the impedance value of the different tissue thicknesses, which are plotted by experimental data in advance. The step of matching to obtain the thickness of the tissue comprises the step of determining the thickness of the tissue as the tissue thickness reflected by the matched base curve when the acquired characteristic curve of the change of the impedance value is matched with one of a plurality of base curves which are drawn and stored in advance through experimental data and reflect the change characteristics of the impedance values of different tissue thicknesses.

Preferably, the acquired impedance value may be a difference between the real-time detected impedance value and the impedance value in the blood.

The controlling step may further comprise immediately stopping the pulsed electric field ablation output when a real-time impedance discontinuity is detected during the pulsed electric field ablation output.

Preferably, the controlling step may further comprise controlling whether the ablation catheter continues pulsed electric field ablation output based on a comparison of the real-time ablation depth and the thickness of the tissue.

Preferably, the pulsed electric field ablation control method may further include calculating a real-time ablation depth according to the ablation parameter and the real-time abutment pressure during the pulsed electric field ablation output.

The real-time ablation depth may be calculated according to the following formula:

,

Wherein 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 overlapping times, CF is the real-time abutment pressure, T is the time variable, and C, α, β are correction coefficients.

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

Preferably, the pulsed electric field ablation control method may further comprise estimating an ablation lesion extent in the tissue based on real-time lesion detection results. Thus, the controlling step may further include controlling whether the ablation catheter continues pulsed electric field ablation output based on the extent of ablation lesions in the tissue.

Preferably, the ablation catheter includes an optical sensor disposed between the electrodes, and the ablation lesion estimation step may include estimating an ablation lesion extent in the tissue based on an optical signal detected by the optical sensor.

Similarly, the ablation catheter includes an ultrasound sensor disposed between electrodes, and the ablation lesion estimation step may include estimating a range of ablation lesions in the tissue from ultrasound imaging signals detected by the ultrasound sensor.

Preferably, the pulsed electric field ablation control method may further include calculating a real-time ablation depth according to the ablation parameter and the real-time abutment pressure during the pulsed electric field ablation output. The step of estimating the ablation damage may further include correcting the real-time damage detection result and the calculated real-time ablation depth to estimate an ablation damage range in the tissue.

Preferably, the contact condition may further include a direction and a positional relationship of abutment and a morphology of the ablation catheter.

The electrodes on the ablation catheter may be bipolar electrodes and minimize the distance between the electrodes of different polarities.

According to a second aspect of the present application, a pulsed electric field ablation control apparatus is provided. The pulse electric field ablation control device can comprise an impedance detection part, a tissue thickness determination part and an ablation control part, wherein the impedance detection part is used for carrying out fine impedance detection on contacted tissues by using electrodes on an ablation catheter, the tissue thickness determination part is used for determining the thickness of the tissues according to the detected impedance change under different contact conditions, and the ablation control part is used for controlling the ablation catheter to carry out pulse electric field ablation output according to the determined thickness of the tissues.

Preferably, the ablation control section may further include an ablation parameter determination unit that determines an ablation parameter based on the portion of the tissue and the determined thickness of the tissue.

Preferably, the pulsed electric field ablation control device further comprises a tissue site determining section that determines a site of the tissue with which the electrode is contacting based on an electrophysiological signal acquired by the electrode.

Preferably, the contact condition comprises an abutment pressure. In the pulsed electric field ablation control device according to the second aspect of the present application, the impedance detecting section may be configured to acquire an impedance value under different abutment pressure conditions for the tissue, and the tissue thickness determining section may be configured to compare a variation characteristic of the acquired impedance value with a pre-stored variation characteristic of the impedance value of different tissue thicknesses, and match the thickness of the tissue.

Specifically, the acquired characteristic of the change in the impedance value may be plotted as a curve, and the prestored characteristic of the change in the impedance value of the different tissue thicknesses may be a plurality of base curves reflecting the characteristic of the change in the impedance value of the different tissue thicknesses, which are plotted by experimental data in advance. The matching to obtain the thickness of the tissue comprises determining the thickness of the tissue as the tissue thickness reflected by the matched base curve when the acquired change characteristic curve of the impedance value is matched with one of a plurality of base curves which are drawn and stored in advance through experimental data and reflect the change characteristics of the impedance values of different tissue thicknesses.

The ablation control section may be further configured to immediately stop the pulsed electric field ablation output when the impedance detecting section detects a real-time impedance discontinuity during the pulsed electric field ablation output.

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

Preferably, the pulsed electric field ablation control device may further include an ablation depth determining section that calculates a real-time ablation depth from the ablation parameter and the real-time abutment pressure during the pulsed electric field ablation output.

The ablation depth determination section may calculate the real-time ablation depth according to the following formula:

,

The ablation control section may be further configured to control the ablation catheter to continue pulsed electric field ablation output when the real-time ablation depth is less than the thickness of the tissue, and to control the ablation catheter to stop ablation when the real-time ablation depth is equal to the thickness of the tissue.

Preferably, the pulsed electric field ablation control device may further include an ablation damage estimating section that estimates an ablation damage range in the tissue based on a real-time damage detection result. Thus, the ablation control section may be further configured to control whether the ablation catheter continues to perform pulsed electric field ablation output according to an ablation lesion range in the tissue.

Preferably, the ablation catheter includes an optical sensor disposed between the electrodes, and the ablation lesion estimation section may be configured to estimate an ablation lesion range in the tissue from an optical signal detected by the optical sensor.

Similarly, the ablation catheter includes an ultrasound sensor disposed between electrodes, and the ablation lesion estimation section may be configured to estimate a range of ablation lesions in the tissue from ultrasound imaging signals detected by the ultrasound sensor.

Preferably, the pulsed electric field ablation control device may further include an ablation depth determining section that calculates a real-time ablation depth from the ablation parameter and the real-time abutment pressure during the pulsed electric field ablation output. The ablation lesion estimation section may be further configured to correct the real-time lesion detection result and the calculated real-time ablation depth to each other, and estimate an ablation lesion range in the tissue.

According to a third aspect of the present application, there is provided a non-transitory computer readable storage medium for storing a computer program. The computer program includes instructions. The instructions, when executed by a processor of an electronic device, cause the electronic device to implement a pulsed electric field ablation control method according to the first aspect of the application.

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 for executing the pulsed electric field ablation control method according to the first aspect of the application according to computer instructions.

The focusing electrode is used on the ablation catheter, so that the impedance of contact tissues and the small impedance change under different contact conditions can be accurately detected. Therefore, the pulsed electric field ablation control technology can accurately detect the impedance change to calculate the tissue thickness and match proper ablation parameters, and avoid complications caused by overlarge ablation parameters. In addition, the pulsed electric field ablation control technology can determine the ablation depth and the catheter, and avoid excessive ablation.

Drawings

The present application will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein like elements are numbered alike, wherein:

FIG. 1 is a schematic illustration of ablation of thick myocardial tissue.

Fig. 2 is a schematic illustration of ablation of thin myocardial tissue.

Fig. 3 is a schematic illustration of ablation of thick myocardial tissue with sufficient applied pressure.

Fig. 4 is a schematic diagram of a first headend electrode arrangement of a bipolar pulsed electric field ablation catheter.

Fig. 5 is a schematic diagram of a second headend electrode arrangement of a bipolar pulsed electric field ablation catheter.

Fig. 6 is a schematic diagram of a third headend electrode arrangement of a bipolar pulsed electric field ablation catheter.

Fig. 7 is a schematic diagram of a fourth headend electrode arrangement of a bipolar pulsed electric field ablation catheter.

Fig. 8 is a schematic view of a headend electrode ablation lesion.

Fig. 9 is a flowchart of a pulsed electric field ablation control method according to an embodiment of the present application.

Fig. 10 is a schematic view of the electrodes slightly contacting the tissue.

Fig. 11 is a schematic diagram of an electrode in contact with an increase in tissue pressure.

FIG. 12 is a schematic diagram showing the impedance change for different pressures.

Fig. 13 shows the effect after different times of ablation.

Fig. 14 is a schematic illustration of an abrupt change in impedance anomaly during ablation.

Fig. 15 shows an ablation head with an optical sensor.

Fig. 16 shows an ablation head with an ultrasound transducer.

Fig. 17 shows an example of the distribution of positioning sensors in an ablation catheter.

Fig. 18 is a schematic view of a pressure sensor in an ablation catheter.

Fig. 19 is a schematic block diagram of a pulsed electric field ablation control device and an ablation catheter in accordance with an embodiment of the application.

Reference numerals:

1 ablation electrode

2 Myocardial tissue

221 Thick myocardial tissue

222 Thin myocardial tissue

3 Ablation lesion extent

41 First ablation electrode

42 Second ablation electrode

51 Third ablation electrode

52 Fourth ablation electrode

53 Fifth ablation electrode

54 Sixth ablation electrode

61 First body head electrode

62 Microelectrode

71 Second body head electrode

72 Tubular electrode

8 Physiological saline

9 Pipe body

10 Pressure sensor

11 Optical sensor

12 Ultrasonic sensor

13 Plant tissue

14 Traction member

15 First magnetic positioning sensor

16 Second magnetic positioning sensor

Lesion extent of 311 ablation once

Lesion extent of 312 ablations three times

313 Lesion extent ablated five times

171 Elastomer

172 First strain sensor

173 Second strain sensor

174 Third strain sensor

Detailed Description

The technical scheme of the present application will be described in further detail below by way of examples with reference to the accompanying drawings, but the present application is not limited to the following examples.

FIG. 1 is a schematic illustration of ablation of thick myocardial tissue. Fig. 2 is a schematic illustration of ablation of thin myocardial tissue. Fig. 3 is a schematic illustration of ablation of thick myocardial tissue with sufficient applied pressure.

As shown in fig. 1 to 3, the ablation electrode 1 is used for ablation under the condition of setting the same ablation parameters, the ablation damage range 3 is basically the same, however, the thick myocardial tissue 221 shown in fig. 1 is thicker and difficult to ablate through the wall, the thin myocardial tissue 222 shown in fig. 2 is thinner and can easily penetrate the wall and damage the surrounding tissues, and compared with fig. 1, the thick myocardial tissue 221 can be ablated through the wall under the condition of enough leaning pressure in fig. 3. Fig. 13 shows the effect after different times of ablation. As shown in fig. 13, the ablation depth on the plant tissue 13 under the same parameter conditions is schematically shown as an ablation once damage range 311, an ablation three-time damage range 312, and an ablation five-time damage range 313. As can be seen from FIG. 13, as the number of ablations increases, the depth of ablation, i.e., the indicated lesion range, increases, and thus factors affecting the transmural effect of the ablative lesion have a direct relationship with the abutment pressure, tissue thickness, ablation parameters, and number of superimposed passes.

In prior art bipolar pulsed electric field ablation catheters, the electrodes are an even number and are distributed axially on the catheter tip in a linear fashion. The existing design has the problems that the contact position is a head electrode, the discharge ablation range is a head electrode and rear electrode area, the rear electrode is usually suspended in the air, and is not contacted with tissues during discharge but is discharged and ablated in blood due to axial linear arrangement, so that a part of energy flows into the blood to influence the ablation and injury efficiency, and meanwhile, excessive ablation is performed in the blood or unnecessary damage is caused to red blood cells of the blood to cause complications such as renal failure.

To avoid ablation unfocusing problems, the present application employs an ablation electrode design as shown in fig. 4-7.

As shown in fig. 4, in the first head end electrode arrangement of the bipolar pulsed electric field ablation catheter, a first ablation electrode 41 and a second ablation electrode 42 are provided at the very top end of the catheter. In 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 are opposite in polarity, and the electrode surface areas of the first ablation electrode 41 and the second ablation electrode 42 are equal, and the area is the most direct contact area of the catheter and the tissue, so that ablation energy can be sufficiently applied to the tissue. Fig. 8 is a schematic view of a headend electrode ablation lesion. As shown in fig. 8, the ablation electrode 1 ablates the myocardial tissue 2, and the ablation lesion area 3 is hemispherical, and ablation energy is concentrated in the myocardial tissue 2. Fig. 4 furthermore shows the body 9 of the ablation catheter and the pressure sensor 10 inside the body, the relevant function of which will be described in further detail later.

As shown in fig. 5, 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 uniformly and symmetrically distributed along the central axis of the catheter, 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, the electrode spacing is 0.1-1mm, and the ablation damage area is concentrated at the head end of the catheter, so that focusing accurate ablation is realized. Fig. 5 furthermore shows the tube body 9 of the ablation catheter.

As shown in fig. 6, in the third head electrode arrangement of the bipolar pulsed electric field ablation catheter, one microelectrode 62 is arranged on the tip of the first body head electrode 61, and 3-6 microelectrodes 62 are uniformly arranged laterally. When ablation is implemented, the polarity of the first main body head electrode 61 is opposite to that of the microelectrode 62, the electrode surface area of the first main body head electrode 61 is equal to the sum of the electrode surface areas of all the microelectrodes 62, the first main body head electrode 61 and all the microelectrodes 62 are mutually independent and insulated, the minimum distance is 0.10-1mm, and the ablation damage area is concentrated at the head end of the catheter, so that focusing accurate ablation is realized. Fig. 6 furthermore shows the tube body 9 of the ablation catheter.

In a fourth head end electrode arrangement of the bipolar pulsed electric field ablation catheter, as shown in fig. 7, a tubular electrode 72 is provided inside the second body head electrode 71. When ablation is implemented, the surface area of the second main body head electrode 71 is smaller than or equal to the inner surface area of the tubular electrode 72, the polarity of the second main body head electrode 71 is opposite to that of the tubular electrode 72, the minimum electrode spacing is 0.10-1.0mm, and the ablation damage area is concentrated at the head end of the catheter, so that focusing accurate ablation is realized. During ablation, the physiological saline 8 is continuously infused into the tubular electrode 72, the contacted second main body head electrode 71 directly contacts the tissue, a loop is formed with the tubular electrode 72 through the tissue or blood and the physiological saline 8, and the tubular electrode 72 is constantly contacted with only the physiological saline 8 in the interior, so that the tissue impedance contacted by the second main body head electrode 71 can also feed back a fine local impedance value. Fig. 7 furthermore shows the body 9 of the ablation catheter and the pressure sensor 10 inside the body, the relevant function of which will be described in further detail later.

In the electrode arrangements shown in fig. 4-7, the inter-electrode distances are all micro-pitches, which accurately mark the electrophysiological signals of the head end contacting the tissue, as well as the local impedance between the head end electrode and the tissue.

In the example shown in fig. 4, the first ablation electrode 41 is spaced from the second ablation electrode 42 by 0.40-1.30mm. The smaller the electrode spacing is, the better the quality of the collected electrophysiological signals is, and the more accurate the tissue part is judged by the electrophysiological signals. Because the electrode head end is in direct contact with the tissue, the electrode head end can directly collect the impedance of the first ablation electrode 41 and the second ablation electrode 42, and the collected impedance value is accurate, so that the problem of inaccurate measurement caused by suspension of the rear end electrode in blood when the traditional front end electrode collects the impedance to the rear end electrode is avoided. Based on the fine electrophysiological signal mapping and the fine impedance monitoring, a tissue site determination and a tissue thickness prediction are performed to give a matched ablation parameter. The ablation depth can be calculated after the abutment pressure, ablation parameters and the number of overlaps are known.

The application provides a pulse electric field ablation control method and device. Specific embodiments of the application are described below in terms of methods and apparatus, respectively.

Control method

As described above, based on accurate electrophysiological signal mapping and fine impedance monitoring, the tissue site to be ablated can be determined, and the tissue thickness can be predicted, so that the ablation catheter is controlled to perform pulsed electric field ablation output. The control of the application comprises determining ablation parameters such as pulse discharge voltage, single effective discharge time, pulse width and superposition times, and also comprises safety monitoring, ablation depth calculation, starting and stopping of an ablation process and the like.

As shown in fig. 9, a pulsed electric field ablation control method 900 in accordance with an embodiment of the application begins at step S910 where fine impedance detection is performed on contacted tissue using electrodes on an ablation catheter.

In step S920, the thickness of the tissue is determined from the detected change in impedance with different contact conditions.

The contact described herein may also be referred to as abutment. Those skilled in the art will appreciate that in the context of the present application, these two terms may be used interchangeably to express the same meaning. The contact condition in step S920 may include the abutment pressure as described previously. In a preferred embodiment, step S910 may specifically include acquiring impedance values for the tissue under different conditions of abutment pressure. Accordingly, step S920 may specifically include comparing the acquired impedance value variation characteristics with pre-stored impedance value variation characteristics of different tissue thicknesses, and matching to obtain the tissue thickness. Specifically, the characteristic of the change in the acquired impedance value may be plotted as a curve. The pre-stored impedance value variation characteristics of different tissue thicknesses may be a plurality of base curves which are pre-drawn through experimental data and which reflect the impedance value variation characteristics of different tissue thicknesses. In other words, each curve represents a tissue thickness in the pre-stored base curve. The matching is achieved by determining the thickness of the tissue as the thickness of the tissue reflected by the matched base curve when the characteristic curve of the change in the acquired impedance value matches one of a plurality of base curves previously plotted by experimental data to preserve the characteristic of the change in the impedance value reflecting the thickness of different tissues. In a preferred embodiment, the acquired impedance values described herein are actually the difference between the real-time detected impedance values and the impedance values in the blood.

Those skilled in the art will appreciate that in some embodiments, the contact conditions described herein may also include the orientation and positional relationship of the abutment and the morphology of the ablation catheter.

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

The control described in step S930 may further include determining ablation parameters.

According to a preferred embodiment of the application, the determination of the ablation parameters is based on a determination of the location of the tissue to be ablated and a determination of the thickness of the tissue. Thus, in addition to step S920, the control method 900 may need to include an additional step of determining the location of the tissue that the electrode of the ablation catheter is contacting based on the electrophysiological signals acquired by the electrode.

Here, the ablation parameters may include pulse discharge voltage, single effective discharge time, pulse width, number of overlaps. Of course, the ablation parameters may also be single ablation parameters in the narrow sense, i.e. they do not include the number of overlaps, but only parameters of single ablations, such as pulse discharge voltage, single effective discharge time, pulse width, etc.

Step S930 may further include immediately stopping the pulsed electric field ablation output when the real-time impedance discontinuity is detected during the pulsed electric field ablation output to ensure the safety of the ablation.

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

Then, according to the comparison result of the real-time ablation depth and the thickness of the tissue, whether the ablation catheter continues to perform pulsed electric field ablation output or not can be controlled. Specifically, when the real-time ablation depth is smaller than the thickness of the tissue, the ablation catheter is controlled to continue pulsed electric field ablation output. And when the real-time ablation depth is equal to the thickness of the tissue, controlling the ablation catheter to stop ablation.

As previously described, the "control" described in step S930 also includes safety monitoring. Specifically, the range of ablation lesions in the tissue may be estimated based on real-time lesion detection results.

For example, the ablation catheter may include an optical sensor disposed between the electrodes. From the optical signals detected by the optical sensor, the extent of ablation lesions in the tissue can be estimated.

Alternatively, the ablation catheter may include an ultrasound transducer disposed between the electrodes. An ablation lesion extent in the tissue is estimated from the ultrasound imaging signals detected by the ultrasound sensor.

The real-time damage detection result can be corrected with the calculated real-time ablation depth no matter from the optical sensor or the ultrasonic sensor, so that the ablation damage range in the tissue can be estimated more accurately. As previously described, during the pulsed electric field ablation output process, the real-time ablation depth can be calculated from the ablation parameters and the real-time abutment pressure.

Further, according to the ablation damage range in the tissue, whether the ablation catheter continues to perform pulsed electric field ablation output or not is controlled.

As mentioned above, since the method of the present application is based on accurate detection of tissue impedance, the proposed aggregate electrode arrangement of the present application has been given above, see fig. 4 to 7. In general, the electrodes on the ablation catheter may be bipolar electrodes and it is desirable to minimize the distance between the electrodes of different polarities.

Embodiment 1 determination of tissue sites

The approximate position of the electrode can be determined by electrophysiological signal detection. The electrophysiological signals collected by the electrodes are proved to be in an atrium if the electrophysiological signals are only provided with an atrial waveform, the electrophysiological signals are proved to be in a ventricle if the electrophysiological signals are only provided with a ventricular waveform, the atrial waveform and the ventricular waveform amplitude are seen if the collected waveforms are provided with an atrial waveform and a ventricular waveform, the position of the tricuspid valve ring or the mitral valve ring is judged if the amplitude is consistent, the position of the atrium near the valve ring is judged to be on the side of the atrium if the amplitude of the atrium is large and the position of the ventricle near the valve ring is judged to be on the side of the ventricle near the valve ring if the amplitude of the atrium is small. The catheter location can be substantially determined based on the electrophysiological signal characteristics. Because the atrial wall is thinner, the ventricular wall is thicker, and muscle tremors are more likely to occur during ablation in the atrium, different parameters are selected at different locations.

Embodiment 2 determination of tissue thickness

As shown in fig. 10, when the first ablation electrode 41 and the second ablation electrode 42 slightly contact the myocardial tissue 2, that is, the abutment pressure is small, the contact area of the electrodes with the tissue is small, and the electrodes are in contact with most of the blood. Since the impedance of the tissue is higher than that of blood, the impedance value acquired by the electrode at this time is relatively small.

As shown in fig. 11, when the pressure at which the first ablation electrode 41 and the second ablation electrode 42 contact the myocardial tissue 2 increases, that is, when the abutment pressure increases, the electrode-tissue contact area increases and the electrode-blood contact area decreases. Since the impedance of the tissue is higher than that of blood, the impedance value collected by the electrode at this time is relatively increased greatly.

FIG. 12 is a schematic diagram showing the impedance change for different pressures. As shown in fig. 12, the above impedance detection characteristics are combined, and the electrode acquisition impedance value Δr (Δr is the difference between the real-time impedance value and the impedance value in blood) will be increased for the same tissue under different pressure conditions, and the characteristics are plotted as a curve, i.e., a T1, T2 or T3 curve in the figure. The variation graph will be different for different myocardial tissues, such as the atrial ventricles, so the tissue thicknesses denoted T1, T2, T3 increase in sequence. For example, as illustrated in fig. 12, T1 to T3 curves are three base curves which are drawn in advance by experimental data and which reflect the characteristics of the impedance value changes of three different tissue thicknesses. In other words, each curve represents a tissue thickness in the pre-stored base curve. In clinic, the tissue thickness is calculated by detecting (plotting according to the detection result) the Δr and pressure F change curves through electrode contact with the tissue, and matching the detected curves with the base curve. That is, when the detected curve matches one of a plurality of base curves previously plotted by experimental data, which are stored as characteristics of changes in impedance values of different tissue thicknesses, the thickness of the tissue is determined as the tissue thickness reflected by the matched base curve.

Embodiment 3 selection of ablation parameters

The ablation parameters are determined by combining the tissue site determined in embodiment 1 and the tissue thickness determined in embodiment 2.

In a preferred embodiment, the ablation parameters may be expressed as:

Wherein V is pulse discharge voltage, T is single effective discharge time, u is pulse width, and n is superposition times. That is, in this preferred embodiment, the ablation parameters include pulse discharge voltage, single effective discharge time, pulse width, and number of stacks.

Embodiment 4 safety monitoring

Safety monitoring may be performed during the ablation process. Since the electrode detection impedance is very fine and sensitive, as shown in fig. 14, if the local impedance between the detection electrodes suddenly increases during the discharge process, i.e. an abrupt impedance change occurs, it indicates that a large micro bubble is generated, and the feedback control system immediately stops ablation.

Embodiment 5-calculation of real-time ablation depth

In the process of pulse electric field ablation output, calculating real-time ablation depth according to the ablation parameters and real-time leaning pressure.

,

Wherein PFADepth is real-time ablation depth, V is pulse discharge voltage, T is single effective discharge time, u is pulse width, n is superposition times, CF is real-time abutment pressure, T is time variable, and C, α, β are correction coefficients.

Embodiment 6-stop of ablation

And (3) calculating the ablation depth in real time in the ablation process, comparing the calculated real-time ablation depth with the tissue thickness acquired before ablation, and if the real-time ablation depth is smaller than the tissue thickness, continuing to ablate until the ablation depth reaches the tissue thickness.

More generally, the determination of whether to stop ablation is based on current lesion assessment. That is, if the current lesion assessment shows that the lesion field reaches a target, e.g., the lesion field reaches a tissue thickness in at least one dimension (i.e., ablation depth), the ablation may be stopped. Conversely, if the current lesion assessment shows that the lesion field has not reached the target, e.g., the lesion field has not penetrated tissue thickness, ablation may continue.

Injury assessment may also be obtained in the following manner.

Fig. 15 shows an ablation head with an optical sensor. As shown in fig. 15, the optical sensor 11 is disposed between the first ablation electrode 41 and the second ablation electrode 42, and the real-time lesion depth of the ablated tissue can be detected. The detection principle is that light is scattered inside the tissue, and the analysis of the internal tissue structure is based on the principle of coherent light interferometry. In low coherence interferometry, light is transmitted in two directions separately, and light reflected or scattered from a target along one path merges or interferes with reflected light from another known reference path. The interference signals are collected into a photoelectric detector, and the tissue structure is determined by analysis, so that the damage and non-damage range can be distinguished. The optical detection ablation damage range can be mutually corrected with the calculated ablation depth in the embodiment 5, so that damage evaluation is more accurate and comprehensive.

Fig. 16 shows an ablation head with an ultrasound transducer. As shown in fig. 16, the ultrasonic sensor 12 is disposed between the first ablation electrode 41 and the second ablation electrode 42, and the real-time lesion depth of the ablated tissue can be detected. The ultrasonic imaging principle is that different echoes generated by the difference of acoustic impedance and attenuation of different tissues form an image. And distinguishing the damaged tissue from the normal tissue boundary through image comparison, and further determining the damaged depth range. The ultrasonic detection ablation damage range can be mutually corrected with the calculated ablation depth in the embodiment 5, so that damage evaluation is more accurate and comprehensive.

Embodiment 7 contact (abutment) case

The contact conditions according to the application include not only the abutment pressure, but also the direction and the positional relationship of the abutment and the morphology of the ablation catheter. These contact conditions can be measured or assessed by means of positioning sensors, pressure sensors, etc.

Fig. 17 shows an example of the distribution of positioning sensors in an ablation catheter. As shown in fig. 17, the catheter tip is provided with a traction member 14. One end of the whole traction device is arranged at the head end of the catheter, and the other end is arranged at the position of the proximal handle assembly. The pulling member 14 is provided as a member of the pulling device, inside the bending direction of the catheter. The traction member 14 is disposed away from the catheter axis. The bending plane of the catheter is perpendicular to the connecting line between the electrodes, namely the center between the two electrodes is a bending direction point for indicating the bending direction. The first magnetic positioning sensor 15 and the second magnetic positioning sensor 16 are respectively arranged at the distal end and the proximal end of the distal tube body and are used for calculating and displaying the bending form of the distal tube body. The first magnetic positioning sensor 15 is composed of two magnetic positioning sensors and forms a certain included angle, the angle is 5-20 degrees, and the first magnetic positioning sensor is used for matching with the pressure sensor to feed back the leaning direction of the catheter.

Fig. 18 is a schematic view of a pressure sensor in an ablation catheter. When the catheter tip contacts tissue, it is necessary to determine the position and direction in which the catheter tip contacts tissue. Accordingly, as shown in the upper diagram of fig. 18, a pressure sensor 10 is provided inside the catheter tip. As shown in the lower diagram of fig. 18, the pressure sensor 10 includes an elastic body 171, and a first strain sensor 172, a second strain sensor 173, and a third strain sensor 174 symmetrically disposed on the elastic body 171. Preferably, 3 or more strain sensors are provided. Preferably, three strain sensors are provided, the included angle between the strain sensors is 120 °, and the zero point (the center point between the electrodes) is aligned with the first strain sensor 172. This way the contact position determined by the pressure sensor is linked to the position relationship determined by the magnetic positioning sensor. The X-axis component Fx, Y-axis component Fy, and Z-axis component Fz are pre-calibration data and known data, and the positional relationship of Fx, fy, and Fz with respect to zero is known. The included angle between the lateral component force (F side) and Fx is b, and can be calculated. Then, as the relation between Fx and the zero point position is known, the angle relation of the zero point position of the < b > can be calculated. Through < a=arctan (Fz/F side), the included angle between the resultant force (F-force) direction and the lateral force can be determined, and the relationship between the resultant force direction and the zero point position can be calculated indirectly. From the calculated +.a and +.b, the direction of catheter contact with the tissue (relative to the zero position) can be determined. The positional relationship between the zero point position and the adjustable bending section of the pipe body can be known from the above. The combination can determine the contact direction and the position relationship between the catheter head end and the tissue and the shape of the catheter.

Control device

As shown in fig. 19, the pulsed electric field ablation control apparatus 1900 according to an embodiment of the present application includes an impedance detecting section 1910, a tissue thickness determining section 1920, and an ablation control section 1930. It will be appreciated by those skilled in the art that the impedance detecting section 1910, the tissue thickness determining section 1920 and the ablation control section 1930 may perform operations corresponding to steps S910, S920 and S930, respectively, in the method 900 of fig. 9.

Specifically, the impedance sensing section 1910 performs fine impedance sensing of the contacted tissue using electrodes on the ablation catheter. The arrow from the ablation catheter to the impedance detection section 1910 in fig. 19 may indicate that electrophysiological signals measured by the catheter through the electrodes are sent to the impedance detection section 1910 for fine impedance detection. The tissue thickness determining section 1920 determines the thickness of the tissue based on the change in the impedance detected by the impedance detecting section 1910 under different contact conditions. The ablation control section 1930 controls the ablation catheter to perform pulsed electric field ablation output according to the thickness of the tissue determined by the tissue thickness determining section 1920. The arrow from the ablation control section 1930 to the ablation catheter in fig. 19 may indicate that the ablation control section 1930 performs ablation output control on the ablation catheter.

The ablation control part 1930 may further include an ablation parameter determining unit (not shown) for determining an ablation parameter 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, number of overlaps. In a preferred embodiment, pulsed electric field ablation control device 1900 may further include a tissue site determining section (not shown) for determining a site of the tissue that the electrode is contacting based on electrophysiological signals acquired by the electrode.

The contact of the catheter (more particularly the electrodes on the catheter) with the tissue can be characterized by the abutment pressure. The impedance sensing portion 1910 may collect impedance values for the tissue under different conditions of applied pressure. Accordingly, the tissue thickness determining section 1920 may compare the acquired change characteristics of the impedance values with the previously stored change characteristics of the impedance values of the different tissue thicknesses, and match the thicknesses of the tissues. Specifically, the acquired change characteristics of the impedance values are plotted as curves, and the prestored change characteristics of the impedance values of different tissue thicknesses are a plurality of base curves which are stored in advance by experimental data and reflect the change characteristics of the impedance values of different tissue thicknesses. When the acquired characteristic curve of the change of the impedance value is matched with one of a plurality of base curves which are drawn and stored in advance through experimental data and reflect the characteristic of the change of the impedance value of different tissue thicknesses, the thickness of the tissue is determined as the tissue thickness reflected by the matched base curve. Preferably, the acquired impedance value is a difference between the real-time detected impedance value and the impedance value in blood.

During pulsed electric field ablation output, the ablation control section 1930 may also immediately stop pulsed electric field ablation output when the impedance detection section 1910 detects a real-time impedance discontinuity.

The ablation control section 1930 may also control whether the ablation catheter continues to perform pulsed electric field ablation output according to a comparison of the real-time ablation depth with the tissue thickness. For example, the pulsed electric field ablation control apparatus 1900 may further include an ablation depth determining section (not shown) for calculating a real-time ablation depth from the ablation parameters and the real-time abutment pressure during the pulsed electric field ablation output. In a preferred embodiment, the ablation depth determination section calculates the real-time ablation depth according to the following formula:

,

The ablation control section 1930 may control the ablation catheter to continue pulsed electric field ablation output 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.

The pulsed electric field ablation control apparatus may further include an ablation lesion estimation section (not shown) for estimating an ablation lesion range in the tissue from the real-time lesion detection results. In this case, the ablation control section 1930 may control whether the ablation catheter continues to perform pulsed electric field ablation output according to the ablation lesion range in the tissue.

In particular, the ablation catheter includes an optical sensor disposed between the electrodes. The ablation damage estimating section may estimate an ablation damage range in the tissue from the optical signal detected by the optical sensor. Alternatively, the ablation catheter includes an ultrasound transducer disposed between the electrodes. The ablation lesion estimation section may estimate an ablation lesion range in the tissue from the ultrasonic imaging signal detected by the ultrasonic sensor.

In this case, the pulsed electric field ablation control apparatus may further include an ablation depth determining section (not shown) for calculating a real-time ablation depth from the ablation parameter and the real-time abutment pressure during the pulsed electric field ablation output. The ablation damage estimation section may further correct the real-time damage detection result and the calculated real-time ablation depth to each other, and estimate an ablation damage range in the tissue.

The contact of the catheter (more particularly the electrodes on the catheter) with the tissue can also be characterized by the direction and positional relationship of the abutment and the morphology of the ablation catheter.

The electrodes on the ablation catheter illustrated herein are bipolar electrodes. The distance between the electrodes of different polarities is minimized. For example, in the electrode arrangements shown in fig. 4-7, the inter-electrode distances are all micro-pitches, which accurately mark the electrophysiological signals that contact the tissue, as well as the local impedance between the tip electrode and the tissue.

It should be understood by those skilled in the art that each part of the pulsed electric field ablation control apparatus and the units included in each part according to the embodiments of the present application may be regarded as functional modules, and may be implemented by computer software, a program, or instructions, respectively, or in whole, and not necessarily be formed by combining each entity hardware through physical or mechanical connection.

Those of ordinary skill in the art will recognize that the methods of the present application may be implemented as computer programs. The methods of the above embodiments, including instructions to cause a computer or processor to perform the algorithms described in connection with the figures, are performed by one or more programs, as described above in connection with the figures. These programs may be stored and provided to a computer or processor using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of the non-transitory computer readable medium include magnetic recording media such as floppy disks, magnetic tapes, and hard disk drives, magneto-optical recording media such as magneto-optical disks, CD-ROMs (compact disk read-only memories), CD-R, CD-R/W, and semiconductor memories such as ROMs, PROMs (programmable ROMs), EPROMs (erasable PROMs), flash ROMs, and RAMs (random access memories). Further, these programs may be provided to a computer by using various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer readable medium may be used to provide a program to a computer through a wired communication path such as electric wires and optical fibers or a wireless communication path.

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 comprising instructions that, when executed by a processor of an electronic device, cause the electronic device to implement a pulsed electric field ablation control method as described previously.

For example, according to one embodiment of the present application, a computer apparatus comprising a processor, a memory and a computer program may also be proposed. Wherein the computer program is stored in the memory and configured to be executed by the processor. The computer program includes instructions for implementing the pulsed electric field ablation control method as previously described.

A pulsed electric field ablation system may be provided by combining a computer program or computing device with the pulsed electric field ablation consumable. The pulsed electric field ablation system may include a pulsed electric field ablation catheter and a controller. The controller is used for executing the pulsed electric field ablation control method or realizing the functions of each part of the pulsed electric field ablation control device according to the computer instructions.

The embodiments of the present application are not limited to the examples described above, and those skilled in the art can make various changes and modifications in form and detail without departing from the spirit and scope of the present application, which are considered to fall within the scope of the present application.

Claims

1. A pulsed electric field ablation control device, comprising:

An impedance detection section for performing fine impedance detection of the contacted tissue using an electrode on the ablation catheter;

a tissue thickness determining section that determines a thickness of the tissue based on a detected change in the impedance under different contact conditions;

A tissue site determining section that determines a site of the tissue with which the electrode is contacting, based on an electrophysiological signal acquired by the electrode;

An ablation control section for controlling the ablation catheter to perform pulsed electric field ablation output according to the region of the tissue and the determined thickness of the tissue,

Wherein the contact condition comprises an abutment pressure, wherein:

The impedance detection section is configured to acquire impedance values for the tissue under different conditions of abutment pressure,

The tissue thickness determining section is configured to draw the variation characteristic of the acquired impedance value as a curve, compare with a plurality of base curves which are drawn by experimental data in advance and which reflect the variation characteristic of the impedance value of different tissue thicknesses, and determine the thickness of the tissue as the tissue thickness reflected by the matched base curve when the variation characteristic of the acquired impedance value matches with one of the plurality of base curves which are drawn by experimental data in advance and which reflect the variation characteristic of the impedance value of different tissue thicknesses.

2. The apparatus according to claim 1, wherein 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 apparatus of claim 2 wherein the ablation parameters include pulse discharge voltage, single effective discharge time, pulse width, number of stacks.

4. The device of claim 1, wherein the acquired impedance value is a difference between the real-time detected impedance value and the impedance value in the blood.

5. The apparatus according to claim 1, wherein the ablation control section is further configured to immediately stop the pulsed electric field ablation output when the impedance detecting section detects a real-time impedance discontinuity during the pulsed electric field ablation output.

6. The apparatus of claim 1, wherein the ablation control section is further configured to control whether the ablation catheter continues pulsed electric field ablation output based on a comparison of a real-time ablation depth and a thickness of the tissue.

7. The apparatus according to claim 6, further comprising an ablation depth determining section that calculates a real-time ablation depth from the ablation parameter and the real-time abutment pressure during the pulsed electric field ablation output.

8. The apparatus according to claim 7, wherein the ablation depth determination section calculates the real-time ablation depth according to the following formula:

,

9. The apparatus of claim 6, wherein the ablation control section is further configured to control the ablation catheter to continue pulsed electric field ablation output when the real-time ablation depth is less than the thickness of the tissue and to stop ablation when the real-time ablation depth is equal to the thickness of the tissue.

10. The apparatus according to claim 1, further comprising an ablation lesion estimation section that estimates an ablation lesion range in the tissue based on a real-time lesion detection result,

The ablation control section is further configured to control whether the ablation catheter continues pulsed electric field ablation output in accordance with an ablation lesion range in the tissue.

11. The apparatus of claim 10, wherein the ablation catheter includes an optical sensor disposed between electrodes, the ablation lesion estimation section configured to estimate a range of ablation lesions in the tissue from an optical signal detected by the optical sensor.

12. The apparatus of claim 10, wherein the ablation catheter includes an ultrasound sensor disposed between electrodes, the ablation lesion estimation section configured to estimate a range of ablation lesions in the tissue from ultrasound imaging signals detected by the ultrasound sensor.

13. The apparatus according to claim 10, further comprising an ablation depth determination section that calculates a real-time ablation depth from an ablation parameter and a real-time abutment pressure during the pulsed electric field ablation output, the ablation damage estimation section being further configured to correct the real-time damage detection result and the calculated real-time ablation depth with each other, and estimate an ablation damage range in the tissue.

14. The device of claim 1, wherein the contact condition further comprises a direction and positional relationship of abutment and a morphology of the ablation catheter.

15. The device of claim 1, wherein the electrodes on the ablation catheter are bipolar electrodes and the distance between the electrodes of different polarities is minimized.