An ablation status assessment system

Abstract

The present application relates to the field of electrophysiology, and particularly relates to an ablation state evaluation system. The system comprises an impedance acquisition device and a control unit. The impedance acquisition device is configured to acquire impedance information of tissue at an ablation site in real time before and after energy delivery at different frequencies. The control unit is configured to calculate a frequency response index based on the received impedance information, obtain an energy delivery difference index at a current position, and obtain an energy delivery difference index of an ablation path in combination with a spatial position of an energy delivery electrode. The impedance information of tissue at the ablation site before and after energy delivery is acquired in real time at different frequencies. The frequency response index of tissue at the ablation site before and after energy delivery is calculated based on the impedance information, an energy delivery difference index at a current position is obtained, and an energy delivery difference index of an ablation path is obtained in combination with a spatial position of an energy delivery electrode. The present application realizes rapid evaluation of the effectiveness of energy delivery on an ablation path during an ablation process.

Description

Technical Field

[0001] This invention relates to the field of electrophysiology, and in particular to an ablation status assessment system. Background Technology

[0002] Currently, the main methods for inducing tissue cell degeneration or apoptosis through energy delivery to tissues include radiofrequency ablation, pulsed ablation, laser ablation, and microwave ablation. Effectiveness assessment during the ablation process is crucial. Besides single-point energy delivery ablation, many ablation procedures involve energy delivery to a defined area. How the state of the ablation area is evaluated during energy delivery directly determines the subsequent energy delivery strategy. The goal is to ensure sufficient energy is applied to the tissue while avoiding excessive energy that unnecessarily expands the area of ​​tissue damage; simultaneously, insufficient energy should also be avoided to prevent failure to achieve the intended therapeutic goal.

[0003] In the field of electrophysiology, depending on the lesion area, various ablation methods are employed, including point-by-point ablation, single-point streaking ablation, and simultaneous multi-point ablation. For example, pulmonary vein electrical isolation requires a closed electrical isolation path formed during energy delivery. In radiofrequency ablation, point-by-point and single-point streaking ablation have long durations, and are significantly affected by respiration and heartbeat, making it difficult to ensure the integrity of the final ablation path and the effectiveness of energy delivery. Pulse ablation has a shorter single-ablation time than radiofrequency ablation, but is still affected by respiration and heartbeat. Point-by-point, single-point streaking, and simultaneous multi-point ablation require complete electrical isolation along the ablation path.

[0004] As can be seen from the above, the assessment of the integrity of the ablation path and the effectiveness of energy delivery is crucial. This invention aims to rapidly assess the effectiveness of energy delivery along the ablation path during the ablation process. Summary of the Invention

[0005] The purpose of this invention is to provide an ablation status assessment system to address the problem that existing technologies cannot timely assess the effectiveness of energy delivery along the ablation path.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An ablation status assessment system includes an impedance acquisition device and a control unit. The impedance acquisition device is configured to acquire impedance information of the tissue at the ablation site before and after energy delivery in real time at different frequencies. The control unit is configured to calculate the impedance frequency response index based on the received impedance information to obtain the energy delivery difference index at the current location, and to obtain the energy delivery difference index of the ablation path by combining the spatial position of the energy delivery electrode.

[0008] As a preferred embodiment of the present invention, in an ablation status assessment system, the impedance acquisition device is further configured as follows:

[0009] The first impedance of the tissue at the ablation site before energy delivery is acquired at a first frequency, and the second impedance of the tissue at the ablation site before energy delivery is acquired at a second frequency.

[0010] The first impedance of the tissue at the ablation site after energy delivery is acquired at a first frequency, and the second impedance of the tissue at the ablation site after energy delivery is acquired at a second frequency.

[0011] As a preferred embodiment of the present invention, an ablation status assessment system is provided, wherein the control unit is configured to include:

[0012] The first control unit is configured to calculate a first impedance frequency response index based on a first impedance and a second impedance of the tissue at the ablation site before energy delivery; and to calculate a second impedance frequency response index based on a first impedance and a second impedance of the tissue at the ablation site after energy delivery.

[0013] The second control unit is configured to obtain the energy delivery difference index at the current location using the first and second blocking frequency response indices.

[0014] The third control unit is configured to combine the spatial location of the energy delivery electrode to plot the energy delivery difference index of the ablation path and output it.

[0015] As a preferred embodiment of the present invention, in an ablation status assessment system, the first control unit is further configured to calculate the first and second resistance frequency response indices using the following formulas:

[0016]

[0017] Where α is the correlation coefficient between the energy delivery electrode and the tissue; pos(x,y,z) is the current position of the energy delivery electrode; This represents the first impedance sampled at the first frequency; This indicates the second impedance sampled at the second frequency; This represents the first blood impedance collected when the energy delivery electrode is located in the blood at the first frequency. The second blood impedance is collected by the energy delivery electrode located in the blood at the second frequency.

[0018] As a preferred embodiment of the present invention, an ablation status assessment system is provided, wherein the first control unit is further configured to consider the effect of saline perfusion on the first blood impedance. Second blood impedance The impact is described as follows:

[0019]

[0020] in, Blood resistance without perfusion This is a regression model based on blood impedance and perfusion velocity V under no-perfusion conditions.

[0021] As a preferred embodiment of the present invention, in an ablation status assessment system, the second control unit is further configured to obtain the energy delivery difference index at the current location using the following formula:

[0022]

[0023] in, The first impedance frequency response index at position pos(x,y,z) before energy delivery; The second impedance frequency response index is the second impedance frequency response index at the position pos(x,y,z) after energy delivery.

[0024] As a preferred embodiment of the present invention, an ablation status assessment system, wherein the third control unit is further configured to determine the spatial location of the energy delivery electrode by means of: X-ray fluorescence method, electric field positioning method, magnetic field positioning method, and a combination of electric field and magnetic field positioning method.

[0025] As a preferred embodiment of the present invention, an ablation status assessment system is provided, wherein the control unit is further configured to perform cumulative energy delivery ablation on locations where the ablation effect has not been achieved based on the energy delivery difference index of the ablation path, and to perform supplementary energy delivery ablation on unclosed annular ablation paths.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] This invention enables rapid evaluation of the effectiveness of energy delivery along the ablation path. It acquires impedance information in real time at different frequencies and calculates the differences in energy delivery along the ablation path. This allows for rapid evaluation of the effectiveness of energy delivery along the ablation path during the ablation process. Supplemental energy delivery ablation or supplemental cumulative ablation can be performed as needed to ensure the integrity of the final ablation path and the effectiveness of energy delivery. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of pulmonary vein energy delivery ablation according to the present invention.

[0029] Figure 2 This is a schematic diagram of the distal end of the catheter of the present invention.

[0030] Figure 3 This is a diagram of the ablation status assessment system of the present invention.

[0031] Figure 4 This is a schematic diagram illustrating the situation where the ablation effect is not achieved in the energy delivery difference index assessment of this invention.

[0032] Figure 5This is a schematic diagram illustrating the energy delivery difference index used in this invention to assess the situation where the ablation path is not closed.

[0033] Figure 6 This is a schematic diagram of the ideal ablation and electrical isolation of the pulmonary vein according to the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings.

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0036] Example 1

[0037] An ablation status assessment system includes an interventional device, an impedance acquisition device 301, and a control unit 302. The interventional device is equipped with at least one energy delivery electrode. In this embodiment, the interventional device uses a catheter, which has various morphological designs, such as a basket-shaped catheter or a petal-shaped catheter. The catheter morphology used in this embodiment is as follows: Figure 2 As shown, the energy delivery process involves two types of conduits, each containing at least one electrode. 201 is the distal portion of a linear conduit, 202 is the distal portion of an annular conduit, 203 is the electrode, and 1, 2, ... 11 are electrode numbers.

[0038] Furthermore, the impedance acquisition device 301 is configured to acquire impedance information of the tissue at the ablation site before and after energy delivery in real time at different frequencies; the impedance acquisition device 301 acquires impedance information between the energy delivery electrode and the reference object, or impedance information between the energy delivery electrode and the electrode. Based on the principle that different biological tissues respond differently to frequency, impedance information is acquired by measuring the impedance at multiple frequency points. The acquisition process includes measuring the impedance information at each frequency in a time-division manner, or measuring the impedance information of each frequency component by modulating the mixed frequency and then demodulating it.

[0039] Furthermore, the control unit 302 is configured to calculate the impedance response index based on the received impedance information, obtain the energy delivery difference index at the current position, and then combine it with the spatial position of the energy delivery electrode to obtain the energy delivery difference index of the ablation path.

[0040] Specifically, such as Figure 1The diagram illustrates one application scenario: pulmonary vein energy delivery ablation. 101 represents the left atrium, 102 the right superior pulmonary vein, 103 the right inferior pulmonary vein, 104 the left inferior pulmonary vein, 105 the left superior pulmonary vein, 106 a linear point-to-point energy delivery ablation catheter, 107 a ring-shaped, single-stage controllable multi-electrode energy delivery ablation catheter, and 108 and 109 electrodes. Common energy delivery methods for catheter 106 include radiofrequency ablation and pulse ablation, delivering energy to the lesion area point-to-point or continuously. Common energy delivery methods for catheter 107 include pulse ablation, which can simultaneously deliver energy to tissue using multiple electrodes.

[0041] like Figure 3 The ablation status assessment system shown includes the following steps:

[0042] The first impedance of the tissue at the ablation site pos(x,y,z) before energy delivery is acquired at the first frequency. The second impedance of the tissue at the pos(x,y,z) site before energy delivery ablation was acquired at the second frequency. The first impedance frequency response index was calculated. The first impedance of the tissue at the ablation site pos(x,y,z) after energy delivery was acquired at the first frequency. The second impedance of the tissue at the ablation site pos(x,y,z) after energy delivery was acquired at the second frequency. The second impedance frequency response index was calculated.

[0043] Specifically, in steps 301 and 302, the solution for the impedance frequency response index is as follows:

[0044]

[0045] Wherein, α is the correlation coefficient between the energy delivery electrode and the tissue adhesion; To acquire the first impedance of the tissue at position pos(x,y,z) at the first frequency; To acquire the second impedance of the tissue at position pos(x,y,z) at the second frequency; To obtain the first blood impedance by placing the energy delivery electrode in the blood at the first frequency, The second blood impedance is obtained by the energy delivery electrode located in the blood at the second frequency. All of the above parameters are collected in real time.

[0046] The first impedance frequency response index can be obtained from formula (1). for:

[0047]

[0048] in, The first blood impedance was acquired by placing the electrode in the blood before energy delivery at the first frequency. The second blood impedance is obtained by placing the electrode in the blood before energy delivery at the second frequency.

[0049] The second impedance frequency response index can be obtained from formula (1). for:

[0050]

[0051] in, The first blood impedance is obtained by placing the electrode in the blood after energy delivery at the first frequency. The second blood impedance is the electrode located in the blood after energy delivery at the second frequency.

[0052] Furthermore, radiofrequency ablation is applied in multiple scenarios, including point-by-point or line-by-line ablation. Some applications involve saline perfusion at the distal end of the catheter. Whether or not saline is perfused, and the different flow rates of saline perfusion, affect blood impedance. This relates to the first blood impedance... Second blood impedance The update will be conducted taking into account the influencing factors mentioned above. The update method is described below:

[0053]

[0054] in, The blood impedance is measured without perfusion, and V is the perfusion rate. This is a regression model based on blood impedance and perfusion velocity V under no-perfusion conditions.

[0055] Based on the first impedance frequency response index Second impedance frequency response index Obtain the energy delivery difference index CDiff at the current location pos ;

[0056] Specifically, the energy delivery difference index CDiff pos The calculation formula is:

[0057]

[0058] in, The first impedance frequency response index at position pos(x,y,z) before energy delivery; The second impedance frequency response index is the second impedance frequency response index at the position pos(x,y,z) after energy delivery.

[0059] By combining the spatial location of the energy delivery electrodes, an energy delivery difference index is plotted for the ablation path, and the output shows the differences in energy delivery along the ablation path.

[0060] Specifically, after energy delivery ablation, the catheter moves within the ablation area. The energy delivery difference assessment of the ablation path is performed by combining the spatial location of the energy delivery electrode, depicting and recording the difference index of energy application along the ablation path, and outputting the energy delivery difference of the ablation path. The methods for determining the spatial location of the energy delivery electrode include X-ray fluorescence method, electric field localization method, magnetic field localization method, and combined electric and magnetic field localization.

[0061] Specifically, different frequencies are selected: a first frequency less than 3kHz and a second frequency greater than 20kHz. Impedance information of the tissue at the ablation site before and after energy delivery is collected in real time using an impedance acquisition device. The control unit calculates the impedance response index based on the received impedance information. When the first frequency is less than 3kHz and the second frequency is greater than 20kHz, the impedance response index ranges from (0,1). Therefore, the energy delivery difference index of the ablation path also ranges from (0,1). The energy delivery difference index is segmented, and different colors are marked at the ablation location to represent different ablation effects. Figure 4 , 5 The output shown is a graph evaluating the energy delivery difference index.

[0062] like Figure 4 , 5 As shown in Figure 6, taking the schematic diagram of the left upper pulmonary vein isolation as an example, combined with the positioning system, at the opening of the pulmonary vein, the moving catheter measures the impedance information before and after energy delivery to determine the energy delivery difference index on the ablation path. Under normal circumstances, according to the evaluation diagram, the different colors, depths, and brightness can reflect the effectiveness of energy delivery to the tissue.

[0063] like Figure 6 The figure shows the energy delivery difference index assessment under ideal conditions. The energy delivery difference index varies greatly along the ablation path, and the ring ablation path forms a closed path, achieving the effect of pulmonary vein electrical isolation.

[0064] like Figure 4 As shown, 401 is the measurement location of the energy delivery difference index on the ablation path. The ablation path is closed. Based on the different colors, shades, and brightness of 401, it can be determined that there are locations where the ablation effect has not been achieved. Supplemental energy delivery ablation is performed on the locations with lighter colors.

[0065] like Figure 5As shown, 501 is the distal end of the catheter, 502 is the catheter electrode, and the different colors, shades, and brightness of 503 reflect the effectiveness of energy delivery to the tissue. It is obvious that the difference index of electrode segments 7-8-9 is significantly smaller, indicating that there are positions where the ablation effect has not been achieved and that they do not form a closed ablation path. This suggests that electrode segments 7-8-9 need to perform cumulative energy delivery ablation on the positions where the ablation effect has not been achieved and supplementary energy delivery ablation on the positions where a closed ablation path has not been formed. The effectiveness of energy delivery in electrode segments 5-6 is significantly smaller than that in segments 1-2-3-4-5, indicating that cumulative energy delivery ablation can be performed in segments 6-7.

[0066] In summary, this invention acquires impedance information before and after energy delivery at different frequencies to obtain the impedance response index, further obtains the energy delivery difference index at the current location, and combines it with the spatial location of the energy delivery electrode to obtain the energy delivery difference index of the ablation path. This enables rapid evaluation of the effectiveness of energy delivery on the ablation path. For locations that do not constitute a closed ablation path, supplementary energy delivery ablation is performed, and for locations with significantly smaller difference indices, supplementary cumulative ablation is performed, ensuring the integrity of the final ablation path and the effectiveness of energy delivery.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ablation status assessment system, characterized in that, The device includes an impedance acquisition device (301) and a control unit (302). The impedance acquisition device is configured to acquire impedance information of the tissue at the ablation site before and after energy delivery in real time at different frequencies. The control unit is configured to calculate the impedance response index based on the received impedance information to obtain the energy delivery difference index at the current location, and to obtain the energy delivery difference index of the ablation path by combining the spatial position of the energy delivery electrode. The control unit includes a first control unit and a second control unit. The first control unit (312) is further configured to calculate the first and second stop frequency response indices using the following formulas: in, It is the correlation coefficient between the energy delivery electrode and the tissue; pos(x,y,z) is the current position of the energy delivery electrode; This represents the first impedance sampled at the first frequency; This indicates the second impedance sampled at the second frequency; This represents the first blood impedance collected when the energy delivery electrode is located in the blood at the first frequency. The second blood impedance was collected by the energy delivery electrode located in the blood at the second frequency. The second control unit (322) is further configured to obtain the energy delivery difference index at the current location using the following formula: in, The first impedance frequency response index at position pos(x,y,z) before energy delivery; The second impedance frequency response index is the second impedance frequency response index at the position pos(x,y,z) after energy delivery.

2. The ablation status assessment system according to claim 1, wherein the impedance acquisition device (301) is further configured as follows: The first impedance of the tissue at the ablation site before energy delivery is acquired at a first frequency, and the second impedance of the tissue at the ablation site before energy delivery is acquired at a second frequency. The first impedance of the tissue at the ablation site after energy delivery is acquired at a first frequency, and the second impedance of the tissue at the ablation site after energy delivery is acquired at a second frequency.

3. The ablation status assessment system according to claim 2, wherein the control unit (302) is configured to include: The first control unit (312) is configured to calculate a first impedance frequency response index based on the first and second impedances of the tissue at the ablation site before energy delivery; The second impedance frequency response index is calculated based on the first and second impedances of the tissue at the ablation site after energy delivery. The second control unit (322) is configured to obtain the energy delivery difference index at the current location using the first blocking frequency response index and the second blocking frequency response index; The third control unit (332) is configured to plot an energy delivery difference index of the ablation path in conjunction with the spatial position of the energy delivery electrode, and output it.

4. The ablation status assessment system according to claim 3, characterized in that, The first control unit (312) is further configured to take into account the effect of saline perfusion on the first blood impedance. The second blood impedance The impact is described as follows: in, Blood resistance without perfusion This is a regression model based on blood impedance and perfusion velocity V under no-perfusion conditions.

5. The ablation status assessment system according to claim 3, characterized in that, The third control unit (332) is further configured to determine the spatial location of the energy delivery electrode in the following ways: x-fluorescence method, electric field positioning method, magnetic field positioning method, and a combination of electric field and magnetic field positioning method.

6. The ablation status assessment system according to claim 1, characterized in that, The control unit (302) is further configured to perform cumulative energy delivery ablation on locations where ablation effect has not been achieved, and to perform supplementary energy delivery ablation on unclosed annular ablation paths, based on the energy delivery difference index of the ablation path.

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