CN116919574A

CN116919574A - Ablation device, impedance detection method and pulsed electric field ablation system

Info

Publication number: CN116919574A
Application number: CN202310931478.5A
Authority: CN
Inventors: 许元兴; 张牧原; 毛自方; 沈刘娉
Original assignee: Shanghai Microport EP MedTech Co Ltd
Current assignee: Shanghai Microport EP MedTech Co Ltd
Priority date: 2023-07-26
Filing date: 2023-07-26
Publication date: 2023-10-24

Abstract

The invention provides an ablation device, an impedance detection method and a pulsed electric field ablation system. The ablation device comprises an impedance detection circuit, a pulse ablation circuit and a catheter, wherein the impedance detection circuit is used for detecting the equivalent impedance of the pulse ablation circuit before the pulse ablation circuit performs discharge ablation. So configured, the control logic with reasonable design is adopted, and the control logic can be matched with the working mode of the multiple electrodes, so that the problem that the ablation equipment with multiple electrodes in the prior art lacks a comprehensive detection means is solved.

Description

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

Technical Field

The invention relates to the technical field of pulsed electric field ablation, in particular to an ablation device, an impedance detection method and a pulsed electric field ablation system.

Background

Catheter ablation based on pulmonary vein isolation is one of the important means of atrial fibrillation treatment. The current ablation means commonly used in clinic often use radio frequency energy or cryogenic energy. However, whether radiofrequency or cryo, ablation energy lacks selectivity for destruction of tissue in the ablation region and relies on the force of the catheter against, potentially damaging adjacent esophageal, coronary and phrenic nerves; in addition, because the radio frequency and the freezing belong to the thermal ablation technology, the radio frequency and the freezing are limited by a heat sink effect, and the full-layer transmutation is difficult to achieve, so that the treatment effect is influenced.

The heart pulse electric field ablation is a novel ablation mode using a pulse electric field as energy. By designing a proper pulse electric field, a plurality of pulse waveform combinations with low pulse width (microsecond or even nanosecond) and high voltage are adopted to release ablation energy, so that the cell membrane of the myocardial cell generates tiny pore-electroporation, the balance of the internal and external ions of the myocardial cell is broken, and the death of the myocardial cell is induced. In contrast to conventional radio frequency and cryogenics, pulsed electric field ablation is nonthermal ablation. In addition, since the threshold value of the pulsed electric field of the cardiomyocytes is the lowest, the pulsed electric field can selectively damage the myocardium, and the blood vessels, nerves and tissues around the heart, such as the lung, esophagus, phrenic nerves and the like, are reserved.

The catheter forms in the pulse ablation system are various, and the number, shape and discharge mode of the catheter electrodes of each manufacturer are different. More and more clinicians indicate that multi-electrode, bipolar or multipolar discharge modes are the direction of future development. A bipolar or multipolar discharge mode refers to a discharge between one or more pairs of conduit electrodes. The parameters are properly designed, and the bipolar or multipolar discharge mode does not generate the problem of muscle contraction basically compared with the monopolar discharge mode (the discharge of the catheter electrode to the neutral electrode plate). In addition, the bipolar or multipolar discharge mode has high efficiency, and the annular ablation stove can be formed once or in a plurality of steps. The multi-turn and multi-electrode catheter with special shape can simultaneously perform three-dimensional spiral ablation on the pulmonary veins, thereby improving the pulmonary vein isolation efficiency and shortening the operation time. However, because of the large number of catheter electrodes, there is a risk that the catheter electrodes of different polarities will overlap together in the patient's body to cause a short circuit. Short-circuit discharge of conduit electrodes with different polarities can cause damage to switching elements in equipment due to overlarge instantaneous current, and serious damage can be caused to patients; therefore, the pulse ablation system needs to have the capability of configuring different discharge modes and detecting the short circuit of the catheter electrode in the different discharge modes.

In addition, the success rate of the pulse ablation system operation depends on the degree of the adhesion between the catheter electrode and the tissue, and the deeper the ablation focus is generated when the catheter electrode is in good adhesion, the greater the possibility of achieving pulmonary vein isolation. Good tissue adhesion can also avoid the generation of bubbles and air embolism. The pressure big head catheter can generally judge the leaning degree of the catheter and the tissue according to the pressure value acquired by the pressure sensor on the catheter electrode at the head end of the catheter, but the multi-circle and multi-electrode catheter is difficult to judge the leaning degree in the same mode due to the structure, the manufacturing process and the like.

In summary, the multi-electrode ablation devices of the prior art lack comprehensive detection means for multiple modes of operation for multiple application scenarios, e.g., short circuit detection for multiple discharge modes such as monopolar, bipolar, multipolar, etc.; detecting the impedance and the comprehensive impedance of the discharge section, the non-discharge section and the section, and rapidly judging whether the multi-electrode pulse ablation catheter has the risk of short circuit or too close distance of the catheter electrode; and judging the contact degree of the catheter electrode and the tissue, and the like.

Disclosure of Invention

The invention aims to provide an ablation device, an impedance detection method and a pulse electric field ablation system, so as to solve the problem that a multi-electrode ablation device in the prior art lacks a comprehensive detection means.

In order to solve the above technical problem, according to a first aspect of the present invention, there is provided an ablation device including an impedance detection circuit, a pulse ablation circuit, and a catheter, the pulse ablation circuit including a switch module and at least two catheter electrodes, the switch module being configured to control each of the catheter electrodes to be individually disconnected, to become positive or to become negative, the at least two catheter electrodes being sequentially disposed along the catheter.

The impedance detection circuit is used for detecting the equivalent impedance of the pulse ablation circuit before the pulse ablation circuit performs discharge ablation work.

Optionally, the catheter is spiral.

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

The impedance module is used for detecting equivalent impedance of a circuit connected with the impedance module.

The impedance detection branch is used for connecting the pulse ablation circuit and the impedance detection module, and a compensation resistor is connected in series between the pulse ablation circuit and the impedance detection module.

Optionally, the impedance detection circuit further comprises at least one of a calibration branch, a lower limit branch, and an upper limit branch.

The calibration leg, the lower limit leg, the upper limit leg, and the impedance detection leg are independently connected to or disconnected from the impedance detection module by switching elements.

The calibration branch is connected with the impedance detection module to provide a calibration resistor, and the impedance detection module is used for configuring calibration parameters based on the detected impedance and a pre-stored resistance value of the calibration resistor.

The lower limit branch is connected with the impedance detection module to provide a lower limit resistor, and the impedance detection module obtains lower limit precision based on the detected impedance and a pre-stored resistance value of the lower limit resistor.

The upper limit branch is connected with the impedance detection module to provide an upper limit resistor, and the impedance detection module obtains upper limit precision based on the detected impedance and a pre-stored resistance value of the upper limit resistor.

The lower limit resistance and the upper limit resistance are set based on a range of equivalent impedances of the ablation device when operating normally.

In order to solve the above technical problem, according to a second aspect of the present invention, there is provided an impedance detection method applied to the above ablation device.

The impedance detection method comprises the following steps: outputting a control signal to drive the states of all the switch elements in the switch module to accord with a preset state; detecting an equivalent impedance of the pulse ablation circuit based on the impedance detection circuit; and obtaining a detection result based on the equivalent impedance.

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

and outputting a control signal to drive the impedance detection branch to be independently connected with the pulse ablation circuit, the compensation resistor and the impedance detection module.

Optionally, the impedance detection circuit further comprises at least one of a calibration branch, a lower limit branch and an upper limit branch, and before detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, the impedance detection method further adaptively comprises at least one of the following steps based on the specific structure of the impedance detection circuit:

and outputting a control signal to drive the calibration branch to be independently connected with the impedance detection module, wherein the impedance detection module configures the calibration parameters.

And outputting a control signal to drive the lower limit branch to be independently connected with the impedance detection module, wherein the impedance detection module obtains the lower limit precision.

And judging whether the lower limit value precision meets the working requirement or not.

And outputting a control signal to drive the upper limit branch to be independently connected with the impedance detection module, wherein the impedance detection module obtains the upper limit precision.

And judging whether the upper limit value precision meets the working requirement.

Optionally, the conduit is spiral, and the conduit is arranged from inside to outside in the 1 st turn to the N th turn ₁ Circle, N ₁ For the total number of turns of the catheter, the impedance detection method includes:

outputting control signals to drive each switch element in the switch module to be turned on or turned off, so that the conduit electrode in the ith circle is one of the positive electrode and the negative electrode, the conduit electrode in the (i+1) th circle is the other electrode of the positive electrode and the negative electrode, and the other conduit electrodes are disconnectedThe method comprises the steps of carrying out a first treatment on the surface of the Wherein, the value of i ranges from 1 to N ₁ -2。

And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit at each different value of i.

Calculating R _{Nominal scale} The sum of the equivalent impedances corresponding to all different i values +. ₂ Wherein N is ₂ 1 st turn to N th turn ₁ -the total number of catheter electrodes in 1 turn.

And, R is _{Nominal scale} Is set to a nominal resistance value of the catheter electrode.

Optionally, the catheter electrodes are disposed along the catheter from the 1 st catheter electrode to the M-th catheter electrode, M being the total number of the catheter electrodes, and the impedance detection method includes:

Outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the j-th conduit electrode is one of the positive electrode and the negative electrode, the j+1th conduit electrode is the other electrode of the positive electrode and the negative electrode, and the other conduit electrodes are disconnected; wherein, the value range of j is from 1 to M-1.

At each different value of j, the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit and is set as R _j 。

If R is ₁ ＞A*R _{Nominal scale} Judging that the 1 st catheter electrode is well attached; if R is ₁ ≤B*R _{Nominal scale} Judging that the 1 st catheter electrode is poor in contact; in other cases, the catheter electrode of 1 st is judged to be in general abutment.

When j is not equal to 1, if R _j ＞A*R _{Nominal scale} And R is _j-1 ＞A*R _{Nominal scale} Judging that the j-th catheter electrode is well attached; if R is _j ≤B*R _{Nominal scale} And R is _j-1 ≤B*R _{Nominal scale} Judging that the j-th catheter electrode is poor in adhesion; in other cases, it is judged that the jth catheter electrode is in general abutment.

If R is _M-1 ＞A*R _{Nominal scale} Judging that the M th catheter electrode is well attached; if R is _M-1 ≤B*R _{Nominal scale} Judging that the M th catheter electrode is poor in adhesion; in other cases, the M-th catheter electrode is judged to be in general abutment.

Wherein A and B are preset parameters, and A > B.

outputting control signals to drive each switch element in the switch module to be turned on or turned off so as to enable the jth switch element to be connected with the jth switch element ₁ The conduit electrode becomes one of the positive electrode and the negative electrode, so that the jth electrode ₂ The other conduit electrode is disconnected by forming the conduit electrode as the other electrode of the positive electrode and the negative electrode; wherein the ordered array (j ₁ ，j ₂ ) Traversal j ₁ <j ₂ ，j ₁ The value range of (1) is 1-M, j ₂ In all cases where the value of (2) is in the range of 1 to M.

For each different ordered array (j ₁ ，j ₂ ) Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, and judging whether the equivalent impedance is smaller than a first short-circuit threshold value; if the value is smaller than the preset value, judging the j ₁ The catheter electrode and j ₂ A short circuit condition exists between the duct electrodes.

Outputting control signals to drive each switch element in the switch module to be turned on or turned off so as to enable the jth switch element to be connected with the jth switch element ₁ The conduit electrode becomes one of the positive electrode and the negative electrode, so that the jth electrode ₂ The M-th catheter electrode becomes the other electrode of the positive electrode and the negative electrode, and the other catheter electrodes are disconnected; wherein the ordered array (j ₁ ，j ₂ ) Traversal j ₁ <j ₂ ，j ₁ The value range of (1) is 1-M, j ₂ In all cases where the value of (2) is in the range of 1 to M.

For each different ordered array (j ₁ ，j ₂ ) Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, and judging whether the equivalent impedance is smaller than a second short-circuit threshold value; if the value is smaller than the preset value, judging the j ₁ The catheter electrode and j ₂ At least one of the catheter electrodes from one to the mth has a short circuit condition.

Optionally, the discharge ablation is performed based on the complete catheter, and the impedance detection method includes:

before discharge ablation work, outputting a control signal to drive each switch element in the switch module to be turned on or turned off, so that the connection state of all the catheter electrodes is consistent with the connection state of the catheter electrodes in the process of the upcoming discharge ablation work.

And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a third short-circuit threshold value, judging that the discharge ablation operation is ended; otherwise, continuing.

Optionally, the catheter electrode is arranged into at least two sections along the catheter, the catheter electrodes of the same section are adjacent end to end in sequence, and each discharge ablation step in the discharge ablation work is implemented based on one section of the catheter; the impedance detection method comprises the following steps:

in the execution process of the discharge ablation work, the following steps are executed before each discharge ablation step:

and outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the catheter electrode in one section to be used for discharge ablation is one of the positive electrode and the negative electrode, and the other catheter electrodes are the other electrode of the positive electrode and the negative electrode.

Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fourth short-circuit threshold value, judging that the discharge ablation work is ended; otherwise, continuing.

Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fifth short-circuit threshold value, judging that the discharge ablation work is ended; otherwise, continuing.

And outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the connection state of all the catheter electrodes is consistent with the connection state of the catheter electrodes in the process of the upcoming discharge ablation operation.

And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fifth short-circuit threshold value, judging that the discharge ablation operation is ended; otherwise, continuing.

In order to solve the above technical problem, according to a third aspect of the present invention, there is provided a pulsed electric field ablation system including a control module and the above ablation device, the control module being configured to execute the above impedance detection method based on the ablation device.

Optionally, the control module is configured to determine, according to the obtained information, whether to control the ablation device to perform discharge ablation after the impedance detection method is performed.

Compared with the prior art, in the ablation device, the impedance detection method and the pulse electric field ablation system provided by the invention, the ablation device comprises an impedance detection circuit, a pulse ablation circuit and a catheter, wherein the impedance detection circuit is used for detecting the equivalent impedance of the pulse ablation circuit before the pulse ablation circuit executes discharge ablation work. So configured, the control logic with reasonable design is adopted, and the control logic can be matched with the working mode of the multiple electrodes, so that the problem that the ablation equipment with multiple electrodes in the prior art lacks a comprehensive detection means is solved. In some embodiments of the present invention, the following beneficial technical effects are achieved: 1. a plurality of discharge modes such as unipolar discharge, bipolar discharge, and multipolar discharge may be configured. 2. The discharge electrode polarity of the conduit electrode can be arbitrarily configured, and the service life of the switching element is prolonged by alternately switching the discharge electrode polarity. In further embodiments, the ablation device in combination with the associated impedance detection method achieves the following benefits: 3. the impedance detection device can detect various impedance detection modes such as monopole impedance, arbitrary bipolar impedance, discharge section comprehensive impedance, discharge section impedance and non-discharge section impedance. 4. The electrode short circuit or the electrode too close condition of the multi-electrode heart pulse electric field ablation system can be rapidly judged. 5. The quality of the pasting can be detected, and the pasting condition is prompted. In the clinical treatment process, a plurality of different ablation operations can be implemented through a single device, so that the operation time is shortened, the pain of a patient is relieved, and the effectiveness, the reliability and the safety of the ablation process are ensured through a plurality of impedance detection means; significant progress was made.

Drawings

Those of ordinary skill in the art will appreciate that the figures are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention. Wherein:

FIG. 1 is a schematic view of the appearance of a spiral duct according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a circuit portion of an ablation device in accordance with an embodiment of the invention;

FIG. 3 is a schematic circuit diagram of an impedance detecting circuit according to an embodiment of the invention;

FIG. 4 is a flow chart of nominal impedance detection and abutment quality detection according to an embodiment of the present invention;

FIG. 5 is a schematic flow chart of a discharge ablation procedure and impedance detection method performed in an alternate manner according to an embodiment of the present invention;

FIG. 6 is a graph showing the relationship between catheter electrode spacing and inter-electrode impedance according to an embodiment of the present invention;

FIG. 7 is a graph showing the relationship between the average value P of the impedance of adjacent catheter electrodes and the combined impedance Z of the discharge section, the discharge section and the non-discharge section Duan Zukang D according to an embodiment of the present invention.

Wherein:

1-a pulse generating circuit; 2-a switch module; a 3-impedance detection circuit; 4-catheter electrode; 5-neutral electrode.

31-an impedance detection module; 32-a calibration branch; 33-lower limit leg; 34-upper-limit branches; 35-impedance detection branch.

Detailed Description

The invention will be described in further detail with reference to the drawings and the specific embodiments thereof in order to make the objects, advantages and features of the invention more apparent. It should be noted that the drawings are in a very simplified form and are not drawn to scale, merely for convenience and clarity in aiding in the description of embodiments of the invention. Furthermore, the structures shown in the drawings are often part of actual structures. In particular, the drawings are shown with different emphasis instead being placed upon illustrating the various embodiments.

As used in this disclosure, the singular forms "a," "an," and "the" include plural referents, the term "or" are generally used in the sense of comprising "and/or" and the term "several" are generally used in the sense of comprising "at least one," the term "at least two" are generally used in the sense of comprising "two or more," and the term "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance or number of features indicated. Thus, a feature defining "first," "second," "third," or "third" may explicitly or implicitly include one or at least two such features, the term "proximal" typically being one end proximal to the operator, the term "distal" typically being one end proximal to the patient, "one end" and "other" and "proximal" and "distal" typically referring to corresponding two portions, including not only the endpoints, the terms "mounted," "connected," "coupled," or "coupled" are to be construed broadly, e.g., as either a fixed connection, a removable connection, or as one piece; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. Furthermore, as used in this disclosure, an element disposed on another element generally only refers to a connection, coupling, cooperation or transmission between two elements, and the connection, coupling, cooperation or transmission between two elements may be direct or indirect through intermediate elements, and should not be construed as indicating or implying any spatial positional relationship between the two elements, i.e., an element may be in any orientation, such as inside, outside, above, below, or on one side, of the other element unless the context clearly indicates otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

The invention provides an ablation device, an impedance detection method and a pulsed electric field ablation system, which are used for solving the problem that a multi-electrode ablation device in the prior art lacks a comprehensive detection means.

The following description refers to the accompanying drawings.

This embodiment provides a multi-electrode heart pulse electric field ablation device (i.e., ablation device) comprising a spiral catheter, the appearance of which is shown in fig. 1, and in fig. 1, the appearance of a 24-catheter electrode spiral catheter is shown, where R and R schematically represent the radius of the inner ring and the radius of the outer ring of the spiral catheter, respectively.

It will be appreciated that in other embodiments, the shape of the catheter is not limited to a spiral, and that different shapes of catheters may be provided based on different treatment objectives. Thus, the ablation device may also be considered to include a catheter.

The numerals of "1#" and the like "numerals + #" in fig. 1 indicate the 1 st catheter electrode to the 24 th catheter electrode, respectively.

Referring to fig. 2, the circuit portion includes: the pulse generation circuit 1, the impedance detection circuit 3 and the pulse ablation circuit, wherein the pulse ablation circuit comprises a switch module 2, a neutral electrode 5 (i.e. a neutral electrode plate) and at least two catheter electrodes 4.

The switching module 2 is used to control each conduit electrode to be individually disconnected, positive or negative, at least two conduit electrodes being arranged in sequence along a spiral conduit (already illustrated in fig. 1). The numerals of "1#" and the like "numerals + #" in fig. 2 denote catheter electrodes No. 1 to 24, respectively. The reference numerals "20" to "2N" of these "2+ numerals" in fig. 2 are used to refer to the catheter-electrode branches including the catheter-electrode and associated switching elements, N being the total number of catheter-electrodes, e.g. 24 in this embodiment. The reference numerals "K2001" to "K2N01" and "K2002" to "K2N02" in fig. 2 denote the positive electrode switching element and the negative electrode switching element in the above-described catheter electrode branches, respectively. HVP in fig. 2 represents the positive output terminal of the pulse generating circuit 1, and HVN represents the negative output terminal of the pulse generating circuit 1.

The switching module 2 is also used for switching on or off the high voltage pulse energy generated by the pulse generating circuit inside the pulse generating circuit through the switching elements K201 and K202.

The switching element provided in the switching module 2 may be one or a combination of several of a relay, an IGBT, and a MOSFET, or may be a module circuit constructed based on elements such as a relay, an IGBT, a MOSFET, and a transistor.

In the prior art, only the impedance detection is used for judging the contact degree of the catheter electrode and human tissues, or the impedance detection is used for judging whether a single catheter electrode is short-circuited. It has not been proposed to determine whether a short circuit has occurred between the plurality of conduit electrodes by using impedance detection, and specific circuits have not been disclosed. In addition, although the conventional pulse ablation system is mostly designed with an impedance detection circuit, even if the circuit is used for judging the short circuit among a plurality of catheter electrodes, the impedance between the adjacent catheter electrodes can only be detected, namely, whether the short circuit phenomenon exists between the adjacent catheter electrodes can only be detected; whether the non-adjacent conduit electrode has the short circuit phenomenon or not can only be indirectly judged by comparing the impedance of the adjacent conduit electrodes one by one, and the method is not intuitive and time-consuming. For multi-turn multi-electrode catheter, the impedance between the discharge section and the non-discharge section or between the positive electrode and the negative electrode in the discharge section cannot be directly detected. The short circuit of the positive electrode and the negative electrode in the discharge section can cause overlarge bus current and damage a switching element; the catheter electrodes of the discharge and non-discharge segments, if at a relatively close distance from the discharge catheter electrode, will generate an arc, affecting the treatment effect, in both cases the pulse ablation system should recognize and avoid discharge in this case.

In this embodiment, only the impedance detection circuit 3 cannot be simply considered as an innovation point, and in this embodiment, the pulse ablation circuit and the impedance detection circuit are arranged for multiple electrodes, so that the pulse ablation circuit and the impedance detection circuit can be matched for working, an external control system can coordinate the two to work, and the pulse ablation circuit provides preconditions for realizing multiple working modes.

The structure of the switching circuit can also be described as follows: each conduit electrode and the neutral electrode are connected with the positive output end of the pulse generating circuit through an independent switching element, and each conduit electrode and the neutral electrode are connected with the negative output end of the pulse generating circuit through an independent switching element.

Taking the embodiment shown in fig. 2 as an example, the following discharge pattern can be realized.

1. Monopolar discharge mode: any conduit electrode discharges with the neutral electrode plate.

Taking unipolar discharge between the 1 st catheter electrode on the 21 branch and the neutral electrode on the 20 branch as an example, the logic is implemented as follows: closing K2001 and K201 to connect the neutral electrode to a positive direct current bus HVP (positive electrode of a pulse generating circuit); closing K2102, K202 connects the catheter electrode 1 to the negative dc bus HVN (negative electrode of the pulse generating circuit), and simultaneously opens the other switches to form a closed discharge circuit.

2. Bipolar discharge mode: any two pairs of conduit electrodes discharge between them.

Taking bipolar discharge of the 1 st conduit electrode of the 21 branch and the 3 rd conduit electrode of the 23 branch as an example, the realization logic is as follows: closing K2101 and K201 to connect the catheter electrode 1 to the positive direct current bus HVP; closing K2302, K202 connects the conduit electrode 3 to the negative dc bus HVN, while opening the other switches, forming a closed discharge loop.

3. Multistage discharge mode: any of the multiple pairs of conduit electrodes discharge between them.

Taking the 1 st, 3 rd and 5 th catheter-electrodes on the 21, 23, 25 branches and the 2 nd, 4 th and 6 th catheter-electrodes on the 22, 24, 26 branches as examples, the logic is implemented as follows: closing K2101, K2301, K2501, K201 to connect the 1 st, 3 rd and 5 th catheter electrodes to the positive DC bus HVP; and closing K2202, K2402, K2602 and K202 to connect the 2 nd, 4 th and 6 th catheter electrodes to the negative direct current bus HVN, and simultaneously opening other switches to form a closed discharge loop.

4. The electric polarity of the discharge tube is adjustable: any discharge vessel electrode may be cut to either positive or negative polarity.

Taking the 1 st, 3 rd and 5 th conduit electrodes on the 21, 23, 25 branches as positive polarity (positive dc bus HVP) and the 2 nd, 4 th and 6 th conduit electrodes on the 22, 24, 26 branches as negative polarity (negative dc bus HVN) multi-stage discharge as examples, the logic is implemented as shown in table 1:

Table 1 open/close states of switching elements

In table 1, X represents that no dc bus is connected and suspended.

Taking the 1 st, 3 rd and 5 th conduit electrodes 1, 3, 5 on the 21, 23, 25 branches as negative polarity (negative dc bus HVN) and the 2 nd, 4 th and 6 th conduit electrodes 2, 4, 6 on the 22, 24, 26 branches as positive polarity (positive dc bus HVP) for example, the logic is implemented as shown in table 2:

table 2 open/close states of the switching elements

In table 2, X represents that no dc bus is connected and suspended.

The advantage of switchable polarity of the conduit electrodes is that the configuration is flexible and convenient, the discharge process can be completed by using the two modes, and each conduit electrode is provided with two switches, so that the service life of a single switching element can be prolonged by switching in turn.

The impedance detection circuit is used for detecting the equivalent impedance of the pulse ablation circuit before the pulse ablation circuit performs discharge ablation work. The impedance detection circuit is connected to the pulse ablation circuit based on the switching elements K111 and K112.

By the arrangement, detection of multiple scenes in multiple modes can be performed by combining an impedance detection method.

The impedance detection method comprises the following steps: outputting a control signal to drive the states of all the switch elements in the switch module to accord with a preset state; detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit; and acquiring a detection result based on the equivalent impedance.

For possible detection methods, the following are listed:

1. monopole impedance detection: impedance detection between any catheter electrode and neutral electrode.

Taking unipolar impedance detection between the 1 st catheter electrode of the 21 branch and the neutral electrode of the 20 branch as an example, the implementation logic is as follows: closing K2001 and K311, and connecting the neutral electrode to the impedance detection anode ZP; and closing K2102 and K312 to connect the 1 st catheter electrode to the impedance detection negative electrode ZN, and simultaneously opening other switches to form a closed impedance detection loop.

2. Bipolar impedance detection: impedance detection between any two catheter electrode pairs.

Taking bipolar impedance detection between the 1 st catheter electrode of the 21 st branch and the 3 rd catheter electrode of the 23 rd branch as an example, the implementation logic is as follows: closing K2101 and K311 to connect the catheter electrode 1 to the impedance detection anode ZP; closing K2302, K312 connects the catheter electrode 3 to the impedance detection negative electrode ZN, and simultaneously opening the other switches to form a closed impedance detection loop.

3. Multistage impedance detection: multipolar impedance detection (comprehensive impedance detection Z) in the discharge section;

if the 1 st to 6 th conduit electrodes are discharge conduit electrodes, the logic is implemented as follows, taking as an example the multi-stage integrated impedance detection between the 1 st, 3 rd and 5 th conduit electrodes on the 21, 23, 25 branches and the 2 nd, 4 th and 6 th conduit electrodes on the 22, 24, 26 branches: closing K2101, K2301, K2501 and K311 to connect the conduit electrodes 1#, 3#, 5# to the impedance detection anode ZP, and regarding 1#, 3#, 5# as one conduit electrode; and closing K2202, K2402, K2602 and K312 to connect the conduit electrodes 2#, 4#, 6# to the impedance detection negative electrode ZN, and simultaneously opening other switches to form a closed impedance detection loop.

4. Multistage impedance detection: multistage impedance detection of discharge section and non-discharge section (section impedance detection D);

if the 1 st to 3 rd conduit electrodes are discharge conduit electrodes, the 4 th to 6 th conduit electrodes are non-discharge conduit electrodes; taking the 1 st to 3 rd conduit electrodes of the 21, 22 and 23 branches as the 1 st section, and the 4 th to 6 th conduit electrodes of the 24, 25 and 26 branches as the 2 nd section as an example, the impedance detection implementation logic of the sections 1 and 2 is as follows: closing K2101, K2201, K2301 and K311 to connect the conduit electrodes 1#, 2#, 3# to the impedance detection anode ZP, and regarding 1#, 2#, 3# as one conduit electrode; closing K2402, K2502, K2602 and K312 connects the conduit electrodes 4#, 5#, 6# to the impedance detection negative electrode ZN, and can regard the conduit electrodes 4#, 5#, 6# as one conduit electrode, and simultaneously opening other switches to form a closed impedance detection loop.

Referring to fig. 3, the impedance detecting circuit includes an impedance detecting module 31, a calibration branch 32, a lower limit branch 33, an upper limit branch 34, and an impedance detecting branch 35.

The impedance module is used for detecting the equivalent impedance of the circuit connected with the impedance module.

The calibration branch, the lower limit branch, the upper limit branch and the impedance detection branch are all independently connected with or disconnected from the impedance detection module through switching elements.

The calibration branch is connected to an impedance detection module, which configures calibration parameters based on the detected impedance and the pre-stored resistance value of the calibration resistor. The logic of the specific calibration parameters involved in the calibration process may be configured according to actual needs, e.g. by addition or multiplication or by other means. The connection relation of the calibration branch and the impedance detection module is changed by the switching element S301.

The lower limit branch provides a lower limit resistance Rtest1 when connected with an impedance detection module, and the impedance detection module obtains lower limit accuracy based on the detected impedance and a pre-stored resistance value of the lower limit resistance. The specific calculation mode and unit selection of the lower limit value precision can be set according to actual needs, and development description is omitted. The connection relation of the lower limit branch and the impedance detection module is changed by the switching element S302.

The upper limit branch is connected with an impedance detection module to provide an upper limit resistance Rtest2, and the impedance detection module obtains the upper limit value precision based on the detected impedance and the pre-stored resistance value of the upper limit resistance. The specific calculation mode and unit selection of the upper limit precision can be set according to actual needs, and development description is omitted. The connection relation of the upper limit arm and the impedance detection module is changed by the switching element S303.

The lower and upper resistances are set based on a range of equivalent impedances of the ablation device when operating normally. When the lower limit value precision and the upper limit value precision do not reach the standard required by the work, the work is stopped or other calibration schemes can be set according to the actual needs, and the development is not performed here.

In other embodiments, only a part of the calibration branches, the lower limit branches, the upper limit branches, or none of the calibration branches, the lower limit branches, the upper limit branches may be provided, depending on the actual situation, for example, in the case where the component accuracy may be ensured by other devices or external constraints.

The impedance detection branch is used for connecting the pulse ablation circuit and the impedance detection module, and the compensation resistor Rcomp is connected in series between the pulse ablation circuit and the impedance detection module. The connection relationship between the pulse ablation circuit and the impedance detection branch is changed by the switching elements K311 and K312, and the connection relationship between the impedance detection branch and the impedance detection module is changed by the switching element S304.

The switching elements S301, S302, S303, S304, K311, and K312 may be one or a combination of several of a relay, an IGBT, and a MOSFET, or may be a module circuit configured based on elements such as a relay, an IGBT, a MOSFET, and a transistor. Each of Rcal, rtest1, rtest2, and Rcomp is a resistor having a fixed resistance value, and preferably a non-inductive resistor having an accuracy of one thousandth.

Based on the above structure, before detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, the impedance detection method further includes:

the output control signal drives the calibration branch to be connected with the impedance detection module alone, and the impedance detection module configures the calibration parameters. After the pulse equipment is electrified, the switch S301 is closed, the S302, the S303, the S304, the K311 and the K312 are disconnected, and the calibration resistor Rcal is connected to the impedance detection module. The Rcal can be selected from the impedance detection range, a calibration parameter is extracted based on the resistor, and other impedance values accessing the impedance detection loop are detected according to the parameter.

The output control signal drives the lower limit branch to be independently connected with the impedance detection module, and the impedance detection module obtains the lower limit value precision. The pull-in switch S302 turns off S301, S303, S304, K311, and K312, and the verification resistor Rtest1 is connected to the impedance detection main circuit 33.Rtest1 may be the lower limit of the impedance detection range, and the system may detect whether the impedance value is within the accuracy of the lower limit of the impedance detection after power-on, for example, a certain percentage deviation or a certain impedance range deviation or a combination of both. That is, it is determined whether the lower limit accuracy meets the work demand.

The output control signal drives the upper limit branch to be independently connected with the impedance detection module, and the impedance detection module obtains the upper limit value precision. The pull-in switch S303 turns off S301, S302, S304, K311, and K312, and the verification resistor Rtest2 is connected to the impedance detection main circuit 33.Rtest2 may be the upper limit of the impedance detection range, and the system detects whether the impedance value is within the accuracy of the upper limit of the impedance detection after Rtest1 is detected, such as satisfying a certain percentage deviation or a certain impedance range deviation or a combination of both. That is, it is determined whether the upper limit accuracy meets the work demand.

The output control signal drives the impedance detection branch to be independently connected with the pulse ablation circuit, the compensation resistor and the impedance detection module. The pull-in switches S304, K311, and K312 are simultaneously turned off S301, S302, and S303, and the compensation resistor Rcomp and the impedance select between the discharge tube electrodes are connected to the impedance detection module. Because the discharge vessel electrode is at risk of short-circuiting in the patient, i.e. the select is likely to be near zero. The Relec is the equivalent resistance formed by the switching module, the catheter electrode and the neutral electrode in FIG. 2. Generally, the lower the impedance of the connected impedance detection module is, the worse the impedance detection precision is, so that a compensation resistor is required to be added, and the precision of the impedance detection module is improved. The pulse ablation device subtracts the compensation resistance value through a software algorithm to obtain the actual impedance value between the catheter electrodes. The resistance value of Rcomp can be selected according to the impedance detection range and the condition that the impedance of the discharge conduit electrode is close to zero when the discharge conduit electrode is short-circuited. The refe is the equivalent impedance of the human tissue actually connected between the electrodes of the discharge catheter, which varies slightly according to the patient or the ablation site. In fig. 2, rcomp is not shown, but actually exists.

The above steps may also be adaptively set according to the specific structure of the impedance detection circuit. For example, when no calibration branches are provided, steps associated with the calibration branches may be eliminated.

Several exemplary detection procedures are described below.

Nominal impedance detection: the blood impedance value in the heart cavity is generally smaller than the impedance value of myocardial tissue, based on the blood impedance value, a multi-circle 24-catheter electrode annular pulse ablation catheter can be placed into the left atrium of a patient through an introducer sheath under the guidance of a CT image or a three-dimensional mapping system, a nominal impedance detection button on pulse equipment is clicked under the condition that the blood impedance between 1-2 and 2-3 … … 23-24 adjacent catheter electrodes is ensured not to be attached to atrial tissue, and the blood impedance between the 1-2 and 2-3 … … -24 adjacent catheter electrodes can be sequentially detected and can be used as the nominal impedance value of each catheter electrode. However, because the size of the heart cavity of the patient is different, and the skill level and the visual angle limitation of the operation of the catheter by the operator are limited, it is difficult to ensure that the outermost catheter electrode is not contacted with myocardial tissue in the left atrium of each patient, and once a certain catheter electrode of the outer ring is contacted with the tissue, the nominal impedance value of the catheter electrode is affected, and then the quality detection of the adhesion of the catheter electrode is affected; from the schematic diagram of the multi-turn 24-catheter electrode ring pulse ablation catheter in fig. 1, the inner ring is knownThe radius (R) of the inner collar catheter electrode is much smaller than the radius (R) of the outer collar, and therefore the inner collar catheter electrode is less likely to contact the patient's myocardial tissue. The preferred approach is to replace the nominal resistance value of each catheter electrode by the mean value of the blood impedance between adjacent catheter electrodes of the inner ring. Namely: r is R _{Nominal scale} ＝(R _{(inner race 1-inner race 2) blood} +R _{(inner race 2-inner race 3) blood} +R _{(inner race 3-inner race 4) blood} +…)/N。

The above can be summarized as follows: the spiral conduit is arranged from inside to outside from the 1 st turn to the N th turn ₁ Circle, N ₁ The impedance detection method comprises the following steps of:

outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the conduit electrode in the ith circle is one of the positive electrode and the negative electrode, the conduit electrode in the (i+1) th circle is the other electrode in the positive electrode and the negative electrode, and other conduit electrodes are disconnected; wherein, the value of i ranges from 1 to N ₁ -2。

And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit at each different value i.

Calculating R _{Nominal scale} Sum of equivalent impedance corresponding to all different i values +.N ₂ Wherein N is ₂ 1 st turn to N th turn ₁ -total number of catheter electrodes in 1 turn.

And, R is _{Nominal scale} Is set to the nominal resistance value of the catheter electrode.

And (3) detecting the abutting quality: after the nominal impedance of each catheter electrode is obtained, a plurality of circles of 24 catheter electrode annular pulse ablation catheters can be attached to the left upper pulmonary vein mouth under the guidance of a CT image or a three-dimensional mapping system, an attaching quality detection button on a pulse device is clicked to carry out attaching quality detection, and the impedance between adjacent catheter electrodes of 1-2 and 2-3 … … -24 is sequentially detected to be used as attaching impedance R _{Attaching and leaning device} . The judgment standard of whether a certain catheter electrode is well attached is that the attaching impedance R of the catheter electrode and the left and right adjacent catheter electrodes are respectively compared _{Attaching and leaning device} And nominal impedance R _{Nominal scale} Take the 3 rd catheter electrode as an example:

if R is _{(2-3) abutment against} ＞A*R _{Nominal scale} 、R _{(3-4) abutment against} ＞A*R _{Nominal scale} It indicates that 3 catheter electrodes are well-held;

if R is _{(2-3) abutment against} ≤B*R _{Nominal scale} 、R _{(3-4) abutment against} ≤B*R _{Nominal scale} Then it is indicated 3 that the catheter electrode is poorly-abutted;

the rest represents the general abutment of the 3 rd catheter electrode.

According to animal experiment results, the parameter A is generally greater than or equal to the parameter B.

The above can be summarized as follows: the catheter electrodes are arranged along the spiral catheter as 1 st catheter electrode to M th catheter electrode, M is the total number of catheter electrodes, and the impedance detection method comprises:

outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the jth conduit electrode is one of the positive electrode and the negative electrode, the (j+1) th conduit electrode is the other electrode of the positive electrode and the negative electrode, and the other conduit electrodes are disconnected; wherein, the value range of j is from 1 to M-1.

If R is ₁ ＞A*R _{Nominal scale} Judging that the 1 st catheter electrode is well attached; if R is ₁ ≤B*R _{Nominal scale} Judging that the 1 st catheter electrode is poor in contact; in other cases, the 1 st catheter electrode was judged to be in general abutment.

When j is not equal to 1, if R _j ＞A*R _{Nominal scale} And R is _j-1 ＞A*R _{Nominal scale} Judging that the j-th catheter electrode is well attached; if R is _j ≤B*R _{Nominal scale} And R is _j-1 ≤B*R _{Nominal scale} Judging that the electrode of the jth catheter is poorly attached; in other cases, the j-th catheter electrode is judged to be in general abutment.

If R is _M-1 ＞A*R _{Nominal scale} Judging that the electrode of the Mth catheter is well attached; if R is _M-1 ≤B*R _{Nominal scale} Judging that the electrode of the Mth catheter is inadequately attached; in other cases, the M-th catheter electrode is judged to be in general abutment.

Wherein A and B are preset parameters.

In practice, here M is the same as N in the foregoing, but in order to avoid misunderstanding, a new letter designation is chosen.

The flow of nominal impedance detection and abutment quality detection described above can also be understood with reference to fig. 4.

The flow of the present embodiment applied to an ablation procedure is illustrated in fig. 4, including: the catheter is arranged on the left room, the catheter is operated to be abutted against the resistance value of the left room, then an operator clicks a nominal impedance detection button to carry out impedance detection, and the specific operation and calculation process of the impedance detection are as described above. After the detection of the nominal impedance is completed, the catheter is operated to reach the ideal position of the pulmonary vein, and an operator performs the abutment detection by clicking an abutment quality detection button. The specific operation and calculation procedure of the abutment quality detection are as described above. If the adhesion is poor, the operation is carried out again, if the adhesion is poor, the adhesion quality detection is finished if the adhesion is poor, and the subsequent instruction is waited.

Short circuit detection: the catheter electrode has a risk of short-circuiting in the patient, the greater the number of electrodes, the greater the risk of short-circuiting. When electrodes with different polarities in the discharge section are in short-circuit discharge, the instant current is excessively large, switching elements such as IGBT (insulated gate bipolar transistor) and the like are damaged, and even patients are damaged; if the electrode of the non-discharge section is close to the discharge electrode, an arc is generated to affect the treatment effect, so that it is necessary to recognize that the electrode is short-circuited or too close before discharge. From the experimental data of the electrode spacing and the inter-electrode impedance of fig. 7, it can be found that the closer the electrode spacing is in the same physiological saline bath environment, the lower the inter-electrode impedance is, so that whether the discharge electrodes with different polarities have a short circuit or are too close in distance can be detected through the inter-electrode impedance of the electrodes. As described above, the impedance detection circuit and the switching circuit of the present application can easily recognize this situation.

For impedance detection between electrodes, there are several methods in theory:

an alternative is the exhaustive approach, to select one electrode, and to measure the impedance value of that electrode with any other electrode:

1-2、1-3、1-4、1-5、1-6……1-24

2-3、2-4、2-5、2-6……2-24

3-4、3-5、3-6……3-24

……

23-24

according to an arithmetic series summation formula, sn=n (a1+an)/2, and the method needs 276 times of impedance detection at most and is time-consuming; but the shorting electrode can be accurately determined. Any group of detection is smaller than a certain threshold in the detection process, namely the short circuit or the too close distance of the prompting electrode is detected.

That is, the impedance detection method includes:

outputting control signals to drive each switch element in the switch module to be turned on or turned off so as to enable the jth switch element to be connected with the jth switch element ₁ The conduit electrode becomes one of the positive electrode and the negative electrode, so that the jth electrode ₂ The other electrode of the positive electrode and the negative electrode is used as the other electrode, so that the other catheter electrodes are disconnected; wherein the ordered array (j ₁ ，j ₂ ) Traversal j ₁ <j ₂ ，j ₁ The value range of (1) is 1-M, j ₂ In all cases where the value of (2) is in the range of 1 to M.

For each different ordered array (j ₁ ，j ₂ ) Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, and judging whether the equivalent impedance is smaller than a first short-circuit threshold value; if the value is smaller than the preset value, judging the j ₁ Catheter electrode j ₂ A short circuit condition exists between the individual conduit electrodes.

Another alternative is to select one electrode as one polarity for impedance detection and all other electrodes as the other polarity for impedance detection, with impedance between the two polarities being detected:

1-(2～24)

( For example, electrode 1# is used as positive electrode ZP, and electrodes 2# to 24# are used as negative electrode ZN, and can be regarded as one electrode; the same polarity can be considered as a short circuit between each other, and the short circuit detection is not required. )

2-(3～24)

3-(4～24)

……

23-24

The method requires 23 times of impedance detection at most, and any group of detection is smaller than a certain threshold in the detection process, namely the short circuit of the electrodes is prompted or the distance between the electrodes is too short, but the specific short circuit electrodes do not need to be further judged.

That is, the impedance detection method includes:

outputting control signals to drive each switch element in the switch module to be turned on or turned off so as to enable the jth switch element to be connected with the jth switch element ₁ The conduit electrode becomes one of the positive electrode and the negative electrode, so that the jth electrode ₂ The M-th conduit electrode becomes the other electrode of the positive electrode and the negative electrode, and the other conduit electrodes are disconnected; wherein the ordered array (j ₁ ，j ₂ ) Traversal j ₁ <j ₂ ，j ₁ The value range of (1) is 1-M, j ₂ In all cases where the value of (2) is in the range of 1 to M.

For each different ordered array (j ₁ ，j ₂ ) Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, and judging whether the equivalent impedance is smaller than a second short-circuit threshold value; if the value is smaller than the preset value, judging the j ₁ Catheter electrode j ₂ At least one of the electrodes of the first through M-th conduits has a short circuit condition.

The conclusion can be directly adopted or additional steps can be added to determine the accurate short circuit position according to the requirement.

The preferred scheme is as follows: in practical use, it is not necessary to detect the impedance between all the electrodes, and all the electrodes may be divided into a plurality of segments according to the number of the electrodes, each segment being discharged in turn. Therefore, only the segment impedance D of the discharge segment and the non-discharge segment and the comprehensive impedance Z of the positive electrode and the negative electrode in the discharge segment are needed to be detected. For example, for a 24 electrode ring pulse ablation catheter, each 8 electrodes may be divided into 1 segment. The 24 electrodes were divided into 3 segments, namely: the electrode 1# to the electrode 8# are the 1 st section; electrode 9# to electrode 16# are segment 2; electrode 17# to electrode 24# are segment 3. Because the electrode short circuit of the non-discharge section or the electrode short circuit of the same polarity in the discharge section does not generate potential safety hazard, the electrode short circuit condition of the discharge section can be detected by executing impedance detection once according to the following two steps.

In fig. 5, D1, D2, and D3 are shown, where the symbols each represent the segment impedance D of a certain segment, Z1, Z2, and Z3 are shown, and each represents the overall impedance Z of a certain segment, and D and Z are shown, where D represents the segment impedance threshold value for judgment, and Z represents the overall impedance threshold value for judgment. That is, the symbols without "×" represent measured values, and the symbols with "×" represent threshold values.

Step 1: as shown in fig. 5, duan Zukang D1 of the detection discharge section and the non-discharge section, in which the 1 st section is the discharge section, the 2 nd and 3 rd sections are the non-discharge sections, and the electrodes 1# to 8# are one polarity of the impedance detection, for example, the impedance detection anode ZP is connected; electrodes 9# to 24# are the other polarity of impedance detection, such as the access impedance detection negative electrode ZN. And when impedance detection is performed, K311 and K312 are closed to be connected into the impedance detection circuit, and K201 and K202 are opened to avoid the influence of the pulse generation circuit on the impedance detection circuit.

Step 2: as shown in fig. 5, the comprehensive impedance Z1 of the positive electrode (for example, positive dc bus HVP is connected when 1#, 3#, 5#, 7# is discharged) and the negative electrode (for example, negative dc bus HVN is connected when 2#, 4#, 6#, 8# is discharged) in the discharge segment is detected, the 1 st segment is taken as the discharge segment, the 2 nd and 3 rd segments are taken as the non-discharge segments as examples, and the electrodes 1#, 3#, 5#, 7# are one polarity of impedance detection, such as the connection impedance detection positive electrode ZP; electrodes 2#, 4#, 6#, 8# are the other polarity of the impedance detection, such as the input impedance detection negative electrode ZN. And when impedance detection is performed, the K311 and the K312 are closed to connect the pre-discharge electrode into the impedance detection circuit, and meanwhile, the K201 and the K202 and the non-discharge section electrode (electrode 9# to electrode 24 #) are disconnected, so that the influence of the pulse generation circuit and the non-discharge electrode on the impedance detection circuit is avoided.

If no electrode short circuit or electrode distance is too close to an alarm prompt, the discharge of the 8 electrodes in the first section can be started: the electrodes 1# and 3# and the electrodes 5# and 7# are connected with a positive direct current bus HVP; the electrodes 2#, 4#, 6#, 8# are connected to the negative direct current bus HVN. And when in pulse discharge, K201 and K202 are closed to be connected with a pulse generating circuit, and meanwhile, K311 and K312 and electrodes (electrodes 9# to electrode 24 #) of a non-discharge section are opened, so that high-voltage pulse energy is prevented from being introduced into an impedance detection circuit. In addition, the second section and the third section of non-discharge electrodes are disconnected during the discharge of the first section, so that the non-discharge sections are prevented from participating in the pulse discharge.

After the first stage discharge is completed, the second stage Duan Zukang detection D2, the comprehensive impedance detection Z2 and the second stage pulse discharge can be started; and finally, starting the third-section impedance detection D3, the comprehensive impedance detection Z3 and the third-section pulse discharge. The complete pulse discharge logic is shown in fig. 5. The whole discharge process is 3-section discharge, only 6 times of impedance detection are needed, and a complete three-dimensional annular ablation stove can be formed after 1 time of discharge, so that the operation efficiency is high.

FIG. 6 is a graph of impedance versus electrode spacing measured by changing the electrode spacing of two electrodes in a saline bath environment of about 220 Ω (nominal electrode spacing). According to the graph, 1mm, 2mm or other intervals can be selected as alarm thresholds for too close electrodes, and the inter-electrode impedance alarm threshold of adjacent electrodes is P.

Fig. 7 is a graph of the relationship of the impedance average P between adjacent electrodes, the combined impedance Z of the discharge segment, and the discharge segment versus the non-discharge segment Duan Zukang D for a 24-pole annular pulse ablation catheter divided into 3 segments of 8 electrodes each. According to the graph, when the impedance between adjacent electrodes is P, the alarm threshold of the comprehensive impedance of the discharge section is Z, and the alarm threshold of the impedance of the discharge section and the non-discharge section is D. And if any one of Z and D exceeds the alarm threshold, the system does not start pulse discharge, and the short circuit or the too close distance of the electrode is prompted through a display screen or sound and the like.

Further, if it is desired to continue to improve the efficiency of the procedure, the number of segments may be reduced, such as changing the three-segment to a two-segment or even a one-segment. The two-stage electrode can divide the electrode 1# to 12# into one stage and the electrode 13# to 24# into the other stage. The short circuit detection logic is consistent with the discharge logic and the three-section type, and only two-section discharge is needed to be carried out, and impedance detection is carried out for 4 times. One segment refers to all electrodes as one segment, with only discharge segments and no non-discharge segments. The one-stage type electrode short circuit or too close distance can be judged by only carrying out one-time comprehensive impedance detection, and the efficiency is highest. However, the fewer the number of segments, the more the number of electrodes connected in parallel, the lower the comprehensive impedance, and the smaller the phase difference between the comprehensive impedance and the comprehensive impedance alarm threshold value Z, and the easier the false triggering of the short-circuit alarm, so that the requirement of one-stage discharge on the accuracy of the impedance detection circuit is higher. In addition, the greater the number of electrodes discharged simultaneously, the greater the current on the positive and negative buses HVP, HVN in fig. 3, and the greater the stress (e.g., K201, K202 in fig. 3) the power element or switch is subjected to, the more likely it is to be damaged. Therefore, a discharge and short-circuit protection strategy suitable for the whole pulse ablation system needs to be selected in several aspects of discharge efficiency, safety, reliability and the like.

The one-piece working logic can be generalized as: the discharge ablation work is implemented based on a complete spiral catheter, and the impedance detection method comprises the following steps:

before the discharge ablation work, the control signals are output to drive each switch element in the switch module to be turned on or turned off, so that the connection state of all catheter electrodes is consistent with the connection state of the upcoming discharge ablation work. The "connected state is consistent" so that it is understood that if a switching element is in an off state during discharge ablation, then the switching element is also in an off state, and vice versa.

And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a third short-circuit threshold (namely Z), judging that discharge ablation work is ended; otherwise, continuing.

The two-stage and three-stage working logic can be summarized as follows: the catheter electrodes are arranged into at least two sections along the spiral catheter, the catheter electrodes of the same section are adjacent end to end in sequence, and each discharge ablation step in the discharge ablation work is implemented based on one section of the spiral catheter; the impedance detection method comprises the following steps:

The output control signals drive each switching element in the switching module to be turned on or turned off, so that the catheter electrode in one section to be used for discharge ablation is one of the positive electrode and the negative electrode, and the other catheter electrodes are the other electrode of the positive electrode and the negative electrode.

Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fourth short-circuit threshold (namely D), judging that discharge ablation work is ended; otherwise, continuing.

Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fifth short-circuit threshold value, judging that discharge ablation work is ended; otherwise, continuing.

The output control signals drive each switch element in the switch module to be turned on or turned off, so that the connection state of all catheter electrodes is consistent with the connection state of the upcoming discharge ablation operation.

And detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fifth short-circuit threshold (namely Z), judging that discharge ablation work is ended; otherwise, continuing.

The embodiment also provides a pulsed electric field ablation system, which comprises a control module and the ablation device, wherein the control module is used for executing the impedance detection method based on the ablation device.

And the control module is used for judging whether to control the ablation device to execute discharge ablation work according to the acquired information after the impedance detection method is executed.

The pulsed electric field ablation system can also solve the problem that the multi-electrode ablation equipment in the prior art lacks a comprehensive detection means.

In summary, the ablation device, the impedance detection method and the pulsed electric field ablation system provided in the embodiment have the following innovative points:

1. the novel switch circuit is shared by the discharge passage and the impedance detection passage, and through alternate switching, not only can a plurality of discharge modes be realized, but also a plurality of impedance detection modes among the multiple electrodes can be realized, so as to judge whether short circuit occurs among the multiple electrodes.

2. A new short circuit detection method is provided, and by judging the impedance between multiple electrodes, whether short circuit or too close distance between the electrodes occurs is judged.

Further, it is preferable to distinguish between the discharge section and the non-discharge section, detect the section impedance of the discharge section and the non-discharge section, and detect the combined impedance of the positive polarity electrode and the negative polarity electrode in the discharge section, so as to rapidly identify the electrode having a short-circuit risk.

3. Through experiments, a method for determining the comprehensive impedance alarm threshold of the discharge section and the non-discharge section is provided.

4. A pulsed electric field ablation system is provided that includes such entirely new switching circuitry and impedance detection circuitry to enable implementation of such short circuit detection methods.

The beneficial effects of this embodiment are as follows:

1. a plurality of discharge modes such as unipolar discharge, bipolar discharge, and multipolar discharge may be configured.

2. The discharge electrode polarity of the conduit electrode can be arbitrarily configured, and the service life of the switching element is prolonged by alternately switching the discharge electrode polarity.

3. The impedance detection device can detect various impedance detection modes such as monopole impedance, arbitrary bipolar impedance, discharge section comprehensive impedance, discharge section impedance and non-discharge section impedance.

4. The electrode short circuit or the electrode too close condition of the multi-electrode heart pulse electric field ablation system can be rapidly judged.

5. The quality of the pasting can be detected, and the pasting condition is prompted.

The foregoing description is only illustrative of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention in any way, and any changes and modifications made by those skilled in the art in light of the foregoing disclosure will be deemed to fall within the scope and spirit of the present invention.

Claims

1. An ablation device comprising an impedance detection circuit, a pulse ablation circuit, and a catheter; the pulse ablation circuit comprises a switch module and at least two catheter electrodes, wherein the switch module is used for controlling each catheter electrode to be independently disconnected, become an anode or become a cathode, and the at least two catheter electrodes are sequentially arranged along the catheter;

2. The ablation device of claim 1, wherein the catheter is helical.

3. The ablation device of claim 1, wherein the impedance detection circuit comprises an impedance detection module and an impedance detection branch;

the impedance detection module is used for detecting equivalent impedance of a circuit connected with the impedance detection module;

4. The ablation device of claim 3, wherein the impedance detection circuit further comprises at least one of a calibration leg, a lower limit leg, and an upper limit leg,

The calibration branch, the lower limit branch, the upper limit branch and the impedance detection branch are independently connected with or disconnected from the impedance detection module through switching elements;

the calibration branch is connected with the impedance detection module to provide a calibration resistor, and the impedance detection module configures calibration parameters based on the detected impedance and a pre-stored resistance value of the calibration resistor;

the impedance detection module acquires lower limit value precision based on the detected impedance and a pre-stored resistance value of the lower limit resistor;

the impedance detection module acquires upper limit value precision based on the detected impedance and a pre-stored resistance value of the upper limit resistor;

5. An impedance detection method, characterized in that the impedance detection method is applied to the ablation device as set forth in any one of claims 1 to 4; the impedance detection method comprises the following steps:

outputting a control signal to drive the states of all the switch elements in the switch module to accord with a preset state;

Detecting an equivalent impedance of the pulse ablation circuit based on the impedance detection circuit; the method comprises the steps of,

and obtaining a detection result based on the equivalent impedance.

6. The impedance detection method of claim 5, wherein the impedance detection circuit further comprises an impedance detection module and an impedance detection branch, the impedance detection method further comprising the steps of, prior to detecting an equivalent impedance of the pulse ablation circuit based on the impedance detection circuit:

7. The impedance detection method of claim 6, wherein the impedance detection circuit further comprises at least one of a calibration leg, a lower leg, and an upper leg, the impedance detection method further adaptively comprising at least one of the following steps based on a specific configuration of the impedance detection circuit, prior to detecting an equivalent impedance of the pulse ablation circuit based on the impedance detection circuit:

outputting a control signal to drive the calibration branch to be independently connected with the impedance detection module, wherein the impedance detection module configures the calibration parameters;

Outputting a control signal to drive the lower limit branch to be independently connected with the impedance detection module, wherein the impedance detection module obtains the lower limit precision;

judging whether the lower limit value precision meets the working requirement or not;

outputting a control signal to drive the upper limit branch to be independently connected with the impedance detection module, wherein the impedance detection module obtains the upper limit precision; the method comprises the steps of,

and judging whether the upper limit value precision meets the working requirement or not.

8. The impedance detecting method according to claim 5, wherein the conduit is spiral, and the conduit is arranged from inside to outside as 1 st turn to nth turn ₁ Circle, N ₁ For the total number of turns of the catheter, the impedance detection method includes:

outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the conduit electrode in the ith circle is one of the positive electrode and the negative electrode, the conduit electrode in the (i+1) th circle is the other electrode of the positive electrode and the negative electrode, and the other conduit electrodes are disconnected; wherein, the value of i ranges from 1 to N ₁ -2；

Detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit at each different i value;

calculating R _{Nominal scale} The sum of the equivalent impedances corresponding to all different i values +. ₂ Wherein N is ₂ 1 st turn to N th turn ₁ -the total number of catheter electrodes in 1 turn; the method comprises the steps of,

r is R _{Nominal scale} Is set to a nominal resistance value of the catheter electrode.

9. The impedance detecting method according to claim 8, wherein the catheter electrodes are arranged along the catheter as 1 st to M-th catheter electrodes, M being a total number of the catheter electrodes, the impedance detecting method comprising:

outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the j-th conduit electrode is one of the positive electrode and the negative electrode, the j+1th conduit electrode is the other electrode of the positive electrode and the negative electrode, and the other conduit electrodes are disconnected; wherein the value range of j is from 1 to M-1;

at each different value of j, the equivalent impedance of the pulse ablation circuit is detected based on the impedance detection circuit and is set as R _j ；

If R is ₁ ＞A*R _{Nominal scale} Judging that the 1 st catheter electrode is well attached; if R is ₁ ≤B*R _{Nominal scale} Judging that the 1 st catheter electrode is poor in contact; in other cases, the 1 st catheter electrode is judged to be in general contact;

When j is not equal to 1, if R _j ＞A*R _{Nominal scale} And R is _j-1 ＞A*R _{Nominal scale} Judging that the j-th catheter electrode is well attached; if R is _j ≤B*R _{Nominal scale} And R is _j-1 ≤B*R _{Nominal scale} Judging that the j-th catheter electrode is poor in adhesion; in other cases, judging that the j-th catheter electrode is in general contact with the electrode;

if R is _M-1 ＞A*R _{Nominal scale} Judging that the M th catheter electrode is well attached; if R is _M-1 ≤B*R _{Nominal scale} Judging that the M th catheter electrode is poor in adhesion; in other cases, judging that the Mth catheter electrode is in general contact with the electrode;

wherein A and B are preset parameters, and A > B.

10. The impedance detecting method according to claim 5, wherein the catheter electrodes are arranged along the catheter as 1 st to M-th catheter electrodes, M being a total number of the catheter electrodes, the impedance detecting method comprising:

outputting control signals to drive each switch element in the switch module to be turned on or turned off so as to enable the jth switch element to be connected with the jth switch element ₁ The conduit electrode becomes one of the positive electrode and the negative electrode, so that the jth electrode ₂ Each of the catheter electrodes is the other electrode of the positive electrode and the negative electrode, and the other catheter electrodes are used for guidingThe tube electrode is disconnected; wherein the ordered array (j ₁ ，j ₂ ) Traversal j ₁ <j ₂ ，j ₁ The value range of (1) is 1-M, j ₂ All cases of the value range of 1 to M;

11. The impedance detecting method according to claim 5, wherein the catheter electrodes are arranged along the catheter as 1 st to M-th catheter electrodes, M being a total number of the catheter electrodes, the impedance detecting method comprising:

outputting control signals to drive each switch element in the switch module to be turned on or turned off so as to enable the jth switch element to be connected with the jth switch element ₁ The conduit electrode becomes one of the positive electrode and the negative electrode, so that the jth electrode ₂ The M-th catheter electrode becomes the other electrode of the positive electrode and the negative electrode, and the other catheter electrodes are disconnected; wherein the ordered array (j ₁ ，j ₂ ) Traversal j ₁ <j ₂ ，j ₁ The value range of (1) is 1-M, j ₂ All cases of the value range of 1 to M;

12. The impedance detection method of claim 5, wherein the discharge ablation operation is performed based on the complete catheter, the impedance detection method comprising:

before discharge ablation work, outputting a control signal to drive each switch element in the switch module to be turned on or turned off, so that the connection state of all the catheter electrodes is consistent with the connection state of the catheter electrodes in the process of the discharge ablation work to be performed; the method comprises the steps of,

based on the impedance detection circuit, detecting the equivalent impedance of the pulse ablation circuit, judging whether the equivalent impedance is smaller than a third short-circuit threshold value, and if so, judging that the discharge ablation work is ended; otherwise, continuing.

13. The impedance detection method according to claim 5, wherein the catheter electrode is provided in at least two sections along the catheter, the catheter electrodes of the same section are sequentially adjacent end to end, and each discharge ablation step in the discharge ablation work is performed based on one section of the catheter; the impedance detection method comprises the following steps:

Outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the catheter electrode in one section to be used for discharge ablation is one of the positive electrode and the negative electrode, and the other catheter electrodes are the other electrode of the positive electrode and the negative electrode;

detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a third short-circuit threshold value, judging that the discharge ablation work is ended; otherwise, continuing;

detecting the equivalent impedance of the pulse ablation circuit based on the impedance detection circuit, if the equivalent impedance is smaller than a fourth short-circuit threshold value, judging that the discharge ablation work is ended; otherwise, continuing;

outputting a control signal to drive each switching element in the switching module to be turned on or turned off, so that the connection state of all the catheter electrodes is consistent with the connection state of the catheter electrodes in the process of the discharge ablation to be performed; the method comprises the steps of,

14. A pulsed electric field ablation system comprising a control module and an ablation device according to any one of claims 1-4, the control module being configured to perform the impedance detection method according to any one of claims 5-13 based on the ablation device.

15. The pulsed electric field ablation system of claim 14, wherein the control module is configured to determine, based on the obtained information, whether to control the ablation device to perform a discharge ablation procedure after the impedance detection method is performed.