Method, apparatus, and ablation system for determining ablation effect of ablation system

Abstract

A method, apparatus, and ablation system for determining the ablation effect of an ablation system. The ablation system includes a spherical catheter, a back plate electrode, and an energy release device. The spherical catheter includes a catheter and a spherical head end disposed on the catheter, and a plurality of electrodes are arranged on the spherical head end. First, obtain the current overall loop impedance value of the plurality of electrodes through the human body to the back plate electrode, calculate the ablation effective power according to the current overall loop impedance value, and then determine the ablation effect according to the ablation effective power. In this way, the effective power acting on the human tissue can be accurately calculated, so as to accurately evaluate the ablation effect.

Description

Technical Field

[0001] The present application relates to the field of cardiovascular intervention techniques, and particularly to a method and apparatus for determining the ablation effect of an ablation system, as well as an ablation system. Background Art

[0002] Catheter ablation is a common method for treating arrhythmia by introducing energy into the heart through a catheter to ablate specific myocardial cells and eliminate lesions. In the initial catheter ablation clinical operation, the surgical process includes: first determining the puncture point; then puncturing the vein / artery blood vessel at the predetermined site to establish a catheter path from the puncture point to the heart cavity, and performing electrophysiological examination; recording the electrophysiological activities of different parts of the heart, performing appropriate electrical stimulation to induce arrhythmia, analyzing the abnormal electrical waves, and accurately finding the lesion point; then accurately delivering the electrodes of the ablation catheter to the lesion site, sending energy for ablation, blocking the abnormal electrical wave conduction path, so as to cure arrhythmia; performing intracardiac electrophysiological examination after ablation, and if the heart rhythm is normal, the operation is completed. If there is still abnormal heart rhythm, it means that the ablation is incomplete and re-ablation treatment is required. Obviously, such an ablation catheter does not have quantitative data to show the current ablation depth and the size of the ablation area for the surgeon to refer to. The surgeon can only rely on surgical experience and the ability to manipulate the catheter to predict the current ablation depth, and the surgical difficulty is very high, and the requirements for the surgeon are also very high.

[0003] Therefore, there is a need for a method that can predict ablation damage at present. Summary of the Invention

[0004] The present application provides a method for determining the ablation effect of an ablation system. The ablation system includes a spherical catheter, a back plate electrode, and an energy release device. The spherical catheter includes a catheter and a spherical head end disposed on the catheter. A plurality of electrodes are arranged on the spherical head end. The spherical head end abuts against the human tissue to be ablated. The back plate electrode abuts against the surface of the human skin. The energy release device is respectively connected to the spherical catheter and the back plate electrode and is used to provide ablation energy to the electrodes on the spherical catheter. The method includes:

[0005] Obtaining a current overall loop impedance value from the plurality of electrodes through the human body to the back plate electrode;

[0006] Calculating the ablation effective power according to the current overall loop impedance value; and

[0007] Judging the ablation effect according to the ablation effective power.

[0008] Further, calculating the ablation effective power according to the current overall loop impedance value includes:

[0009] Calculating the ablation effective power through the following formula:

[0010]

[0011] Among them, P y is the effective ablation power, P is the total ablation power released to the multiple electrodes, R is the current overall loop impedance value, and R a is the first overall loop impedance value of the multiple electrodes through the human body to the back plate when the spherical head is completely in the human blood, and R b is the second overall loop impedance value of the multiple electrodes through the human body to the back plate when the spherical head is completely wrapped by human tissue.

[0012] Furthermore, the method further includes:

[0013] Determining the abutting state between the current spherical head and human tissue; and

[0014] Determining the ablation effect according to the abutting state.

[0015] Furthermore, determining the abutting state includes:

[0016] Obtaining the current impedance value of each electrode through the human body to the back plate;

[0017] Determining the state of each electrode according to the current impedance value of each electrode through the human body to the back plate, and the state includes a first state where the electrode is in human blood and a second state where the electrode abuts human tissue, including: when the current impedance value is an impedance value of the first order of magnitude, determining that the electrode corresponding to the impedance value is in the first state, and when the current impedance value is an impedance value of the second order of magnitude, determining that the electrode corresponding to the impedance value is in the second state; and

[0018] Judging the abutting state according to the state of each electrode.

[0019] Furthermore, determining the abutting state further includes:

[0020] Obtaining the current impedance value between any two adjacent electrodes on the spherical head. When the current impedance value between any two adjacent electrodes is between them, it indicates that the two adjacent electrodes are in good contact with human tissue.

[0021] Among them, S is the surface area of the spherical head, S'' is the surface area occupied by the two adjacent electrodes, and R b is the second overall loop impedance value of the multiple electrodes through the human body to the back plate when the spherical head is completely wrapped by human tissue, and x is the allowable error value.

[0022] Further, the method further includes:

[0023] Determining the currently allowed maximum ablation power through the following formula:

[0024]

[0025] where P max is the currently allowed maximum ablation power, a is the maximum safe power density of the energy release device, S is the surface area of the spherical head end, and R b is the second overall loop impedance value of the plurality of electrodes through the human body to the back plate when the spherical head end is completely wrapped by human tissue.

[0026] Further, the method further includes: adjusting the position of the spherical head end and / or providing recommended power parameters according to the ablation effective power and / or the abutting state and / or the currently allowed maximum ablation power.

[0027] Further, the ablation effect includes ablation depth and ablation damage.

[0028] The present application also provides a device for judging the ablation effect of an ablation system, including a memory and a processor coupled to the memory, the processor being configured to execute the steps in the method for judging the ablation effect of the ablation system described above based on instructions stored in the memory.

[0029] The present application also provides an ablation system, including:

[0030] A spherical catheter, including a catheter and a spherical head end provided on the catheter, a plurality of electrodes being arranged on the spherical head end, and the spherical head end abutting against human tissue to be ablated;

[0031] A back plate, abutting against the human skin surface;

[0032] An energy release device, respectively connected to the spherical catheter and the back plate, for providing ablation energy to the electrodes on the spherical catheter;

[0033] An impedance monitoring module, for obtaining the current overall loop impedance value from the plurality of electrodes through the human body to the back plate;

[0034] An ablation damage evaluation module, for calculating the ablation effective power according to the current overall loop impedance value and judging the ablation effect according to the ablation effective power.

[0035] A method, device, and ablation system for determining the ablation effect according to an embodiment of the present application. First, obtain the current overall loop impedance value from multiple electrodes through the human body to the back electrode plate, calculate the ablation effective power according to the current overall loop impedance value, and then determine the ablation effect according to the ablation effective power. In this way, the effective power acting on the human tissue can be accurately calculated, so as to accurately evaluate the ablation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The following attached drawings are a part of the specification of the present application, which show embodiments of the present application. The attached drawings and the description of the specification are used together to explain the principle of the present application.

[0037] Figure 1 A schematic diagram of an ablation system according to an embodiment of the present application is shown.

[0038] Figure 2 A flowchart of a method for determining the ablation effect of an ablation system according to an embodiment of the present application is shown.

[0039] Figure 3 A schematic diagram of a loop formed by a single electrode in impedance monitoring according to an embodiment of the present application is shown.

[0040] Figure 4 A schematic diagram of a loop formed by two electrodes in impedance monitoring according to an embodiment of the present application is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the spirit of the content disclosed in the present application will be clearly described below with reference to the drawings and detailed description. After any person skilled in the art in the relevant technical field understands the embodiments of the content of the present application, they can make changes and modifications based on the technology taught by the content of the present application, which do not depart from the spirit and scope of the content of the present application.

[0042] The illustrative embodiments of the present application and their descriptions are used to explain the present application, but not to limit the present application. In addition, elements / components using the same or similar reference numerals in the drawings and embodiments are used to represent the same or similar parts.

[0043] Regarding the use of "first", "second",... etc. in this article, it does not particularly refer to the order or sequence, nor is it used to limit the present application. It is only used to distinguish elements or operations described with the same technical terms.

[0044] Regarding the use of "including", "comprising", "having", "containing", etc. in this article, they are all open-ended terms, that is, they mean including but not limited to.

[0045] Regarding the use of "and / or" in this article, it includes any or all combinations of the described things.

[0046] As used herein, "a plurality of" includes "two" and "more than two"; "a plurality of groups" includes "two groups" and "more than two groups".

[0047] Certain terms used to describe the present application will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of the present application.

[0048] An embodiment of the present application provides an ablation system. As Figure 1 shown, the ablation system of the embodiment of the present application includes a spherical catheter 11, a back plate 12, an energy release device 13, an impedance monitoring module 14, and an ablation damage assessment module 15. The spherical catheter 11 includes a catheter and a spherical head end 1 provided on the catheter. A plurality of electrodes are arranged on the spherical head end. The spherical head end abuts against the human tissue to be ablated. The back plate 12 abuts against the surface of the human skin, preferably against the back skin surface of the human body. The energy release device 13 is respectively connected to the spherical catheter and the back plate, and is used to provide ablation energy to the electrodes on the spherical catheter. The impedance monitoring module 14 is used to obtain the current overall loop impedance value from the plurality of electrodes through the human body to the back plate. The ablation damage assessment module 15 is used to calculate the ablation effective power according to the current overall loop impedance value, and judge the ablation effect according to the ablation effective power.

[0049] Specifically, during use, first, the spherical head end of the spherical catheter is placed into the patient's myocardium through the blood vessel of the human body and closely abuts against the myocardium tissue to be ablated. When the spherical head end is placed in a suitable position, the ablation energy is released to the electrodes on the spherical head end through the energy release device. At this time, the energy release device, the electrodes, the human body between the electrodes and the back plate, and the back plate form an overall loop. In addition, since there are a plurality of electrodes on the spherical head end, a plurality of separate loops are also formed between each electrode and the energy release device, the back plate, and the human body.

[0050] In the above process, when the spherical head end is in different positions, the ablation effect is different. For example, a part of the surface area of the spherical head end will closely adhere to the human tissue to be ablated, while another part of the surface area will be immersed in the blood, which will result in different ablation effects. We hope that the surface area of the spherical head end closely adhering to the human tissue to be ablated is as large as possible, and at the same time, the surface area closely adhering to the human tissue to be ablated is as continuous as possible in a sheet, so as to achieve a better ablation effect. However, before releasing the ablation energy to the electrodes, the prior art cannot predict the ablation effect. In the embodiment of the present application, the ablation effect is predicted by monitoring the contact impedance between the plurality of electrodes on the spherical head end and the myocardium tissue. In addition, the position of the spherical head end can be readjusted or ablation can be directly performed according to the predicted ablation effect, so as to achieve precise ablation.

[0051] In Figure 1 the ablation system, a plurality of electrodes are distributed on the spherical head end 1 of the spherical catheter 11. The plurality of electrodes can be arranged uniformly or non-uniformly on the spherical head end 1. The spherical head end can be a non-compliant balloon. The plurality of electrodes can be the same electrodes. The electrodes can cover the entire surface of the spherical head end. Each electrode is respectively connected to the energy release device 13.

[0052] The energy release device 13 is respectively connected to the ablation catheter 11 and the back plate 12. The back plate 12 is attached to the surface of the human body, so that an ablation circuit is formed between the ablation catheter and the human body. The energy release device can have power setting and display. For example, the energy release device can be a radiofrequency instrument, which releases radiofrequency energy to the electrodes and uses the radiofrequency energy to ablate myocardial tissue.

[0053] The impedance monitoring module 14 is arranged between the interfaces of the energy release device and the plurality of electrodes and the interfaces of the energy release device and the back plate, and is used to obtain the current overall circuit impedance value from the plurality of electrodes through the human body to the back plate. The ablation damage assessment module 15 calculates the ablation effective power according to the current overall circuit impedance value, and judges the ablation effect according to the ablation effective power.

[0054] In this way, the effective power acting on the human tissue can be accurately calculated, so as to accurately evaluate the ablation effect.

[0055] Figure 2 Fig. shows a method for judging the ablation effect of an ablation system according to an embodiment of the present application. This method is used before ablation in the above ablation system to predict the ablation effect. This method includes the following steps S21-S23.

[0056] S21, obtaining the current overall circuit impedance value from the plurality of electrodes through the human body to the back plate.

[0057] As described above, in the ablation system, the energy release device, the electrodes, the human body between the electrodes and the back plate, and the back plate form an overall circuit. After the spherical head end is placed, the current overall circuit impedance value of the overall circuit can be obtained. The energy release device is respectively connected to the plurality of electrodes and the back plate. The current overall circuit impedance value refers to the impedance value between the two interfaces of the energy release device. When the energy release device is a radiofrequency instrument, the current overall circuit impedance value will be displayed on the radiofrequency instrument, and the impedance monitoring module can directly obtain this value from the radiofrequency instrument. Different placement positions of the spherical head end correspond to different current overall circuit impedance values.

[0058] S22, calculating the ablation effective power according to the current overall circuit impedance value.

[0059] In the embodiment of the present application, it is assumed that: the surface area of the spherical head end is S, and the first overall loop impedance value between the two interfaces of the energy release device when the spherical head end is completely in the blood and not close to the tissue is R a , and the second overall loop impedance value between the two interfaces of the energy release device when the spherical head end is completely wrapped by human tissue is R b . Among them, S can be measured in advance, and R a and R b can be obtained in advance through experiments. For example, for obtaining R a , the spherical head end can be completely immersed in the blood, and then the impedance values of multiple electrodes on the spherical head end through the human body to the back plate are measured. The measurement and calculation errors for different human bodies are relatively small, so the differences between different human bodies can be ignored.

[0060] When the spherical head end is normally in contact, a part of the electrodes are immersed in the blood, and the impedance of the current conduction through the blood is denoted as R x , the surface area of this part of the electrodes is denoted as S x , and the current on this area dissipates through the blood; at the same time, a part of the electrodes are in contact with human tissue, and the impedance of the current conduction through human tissue is denoted as R y , the surface area of this part of the electrodes is denoted as S y , and the current on this area all passes through the target tissue; at this time, the current overall loop impedance is denoted as R, the output power of the energy release device is denoted as P, the effective power ratio coefficient is denoted as β, and the ablation effective power is denoted as P y .

[0061] Then the following derivation can be carried out:

[0062] The total electrode area S = S x + S y . The ablation effective power and the electrode area that emits the ablation effective power both follow the same ratio, so there is P y = P × β, S y = S × β, S x = S × (1 - β).

[0063] The resistance is inversely proportional to the area, Thus, it can be obtained that:

[0064] According to the resistance calculation formula of the parallel circuit: It can be obtained that

[0065] Then the effective power

[0066] Therefore, as derived above, in this step, the formula To calculate the effective ablation power.

[0067] S23, judging the ablation effect according to the effective ablation power.

[0068] The ablation effect can be evaluated by the effective ablation power. Under the condition of the same output power, the greater the effective ablation power, the better the ablation effect.

[0069] As described above, the effective power acting on human tissue can be accurately calculated, thereby accurately evaluating the ablation effect.

[0070] In another embodiment of the present application, the ablation effect is judged not only based on the effective ablation power, but also based on the contact state between the spherical tip and the human tissue. The contact state here refers to whether the electrodes contacting the human tissue are multiple electrodes contacting in a sheet or in a scattered manner.

[0071] In one embodiment, the impedance monitoring module 14 also obtains the current impedance value of each electrode from the human body to the back plate. Because multiple separate loops are formed between each electrode and the energy release device, the back plate and the human body, the current impedance value of each electrode from the human body to the back plate can also be obtained, that is, the impedance value between the interface between the energy release device and each electrode and the interface between the energy release device and the back plate, so as to determine the state of each electrode according to the current impedance value of the single electrode.

[0072] Specifically, Figure 3 As shown, the impedance monitoring module 14 monitors the current impedance value of a single electrode through the human body to the back plate. When this electrode is in the blood and when it contacts the myocardial tissue, the current impedance value will be different in magnitude. When the electrode contacts the myocardial tissue, the impedance will increase significantly. Therefore, the abutment state can be judged according to the state of each electrode. When the impedance value is an impedance value of the first order of magnitude, it is judged that the electrode corresponding to the impedance value is in the first state, and when the impedance value is an impedance value of the second order of magnitude, it is judged that the electrode corresponding to the impedance value is in the second state. In the ideal abutment condition, the first order of magnitude is less than the second order of magnitude. In this way, it can be judged whether a single electrode is in contact with the blood or in contact with the myocardial tissue. Since the position of each electrode on the spherical head end is fixed, it can be judged whether the electrode in contact with the myocardial tissue is in sheet contact or dispersed contact, and the ablation effect can be judged accordingly. When multiple adjacent electrodes contact the myocardial tissue in sheets, the ablation effect will be better.

[0073] In one embodiment, a single impedance measurement may be performed using a multimeter that can measure 128 or 256 signals, each corresponding to a different electrode.

[0074] In another embodiment, the impedance monitoring module 14 also obtains the current impedance value between any two adjacent electrodes on the spherical head end. That is, the contact impedance between every two adjacent electrodes and the blood and / or tissue can be obtained by the impedance monitoring module. When the current impedance value between any two adjacent electrodes is within between, it indicates that the two adjacent electrodes are in good contact with the human tissue, where S is the surface area of the spherical head end, S'' is the surface area occupied by the any two adjacent electrodes, and R b is the second overall loop impedance value of the multiple electrodes from the human body to the back plate when the spherical head end is completely wrapped by the human tissue, and x is the allowable error value.

[0075] Specifically, as Figure 4 shown, taking an electrode pair as an example, the surface area occupied by the electrode pair is known and represented by S''. The surface area of the entire spherical head end is known as S. R b is the second overall loop impedance value of the multiple electrodes from the human body to the back plate when the spherical head end is completely wrapped by the human tissue. There is a relationship between them: the impedance is inversely proportional to the surface area. Therefore, in the ideal contact situation, the impedance between this electrode pair should satisfy: Among them, the electrode pairs are in a parallel relationship, so the larger the combined surface area, the smaller the impedance. Therefore, the smaller the impedance, the better the ablation effect.

[0076] In summary, the ablation effect can be judged based on both the ablation effective power and the contact state, including predicting the ablation depth and ablation damage in advance. When the predicted ablation effect is not as expected, the position of the spherical head end in the myocardium can be readjusted until the expected ablation effect is achieved. When the predicted ablation effect reaches the expectation, the subsequent ablation operation can be directly carried out.

[0077] In this way, not only can the effective power acting on the human tissue be accurately calculated, but also the distribution of the effective power on the human tissue can be obtained, so as to more accurately evaluate the ablation depth and ablation effect.

[0078] In one embodiment, a plurality of micro holes are evenly distributed on the spherical head end of the ablation catheter, and saline can be perfused isobarically through the plurality of micro holes. Saline perfusion can reduce the contact impedance. Therefore, in the case of ablation using saline perfusion, the above-mentioned impedance refers to the impedance under the condition of saline perfusion.

[0079] In another embodiment of the present application, the maximum ablation power currently allowed can also be determined.

[0080] Specifically, to avoid thrombus, scab formation, and explosion caused by ablation, the output power of the energy release device needs to be correctly set. The surface area of the spherical head end in contact with the human tissue is the key factor determining the maximum safe and effective power. The larger the surface area of the human tissue in contact, the higher the maximum safe and effective power that can be output. Among them, the maximum safe power = contact surface area × maximum safe power density, and the maximum safe power density a can be obtained through experiments.

[0081] If P y has reached the limit and is close to the maximum safe power, from the power formula it can be concluded that U 2 = a × S y × R y = a × S × R b . From the set output power formula Therefore, the power safety upper limit allowed by the energy release device

[0082] Therefore, the maximum ablation power allowed currently is determined by the following formula:

[0083]

[0084] In summary, the ablation effect can also be judged in combination with the maximum ablation power allowed currently.

[0085] The method for judging the ablation effect of an ablation system according to the embodiments of the present application is introduced above. Through the above method, the ablation effective power, contact state, and maximum safe limit power can be obtained, and the ablation depth and ablation damage can be evaluated based on these, so as to accurately evaluate the ablation effect.

[0086] The embodiments of the present application also provide a device for judging the ablation effect of an ablation system, including a memory and a processor coupled to the memory. The processor is configured to execute the steps in the method for judging the ablation effect of an ablation system described above based on the instructions stored in the memory.

[0087] The present application also provides an ablation system, including:

[0088] A spherical catheter 11, including a catheter and a spherical head end provided on the catheter. A plurality of electrodes are arranged on the spherical head end, and the spherical head end is in contact with the human tissue to be ablated;

[0089] A back plate 12, which is in contact with the surface of the human skin;

[0090] An energy release device 13, which is respectively connected to the spherical catheter and the back plate, and is used to provide ablation energy to the electrodes on the spherical catheter;

[0091] An impedance monitoring module 14 configured to obtain a current overall loop impedance value from the plurality of electrodes, through a human body, to the back plate electrode; and

[0092] An ablation damage assessment module 15 configured to calculate an effective ablation power based on the current overall loop impedance value and determine an ablation effect based on the effective ablation power.

[0093] In addition, the impedance monitoring module 14 and the ablation damage assessment module 15 may further perform steps in other embodiments of the method for determining an ablation effect of the ablation system described above.

[0094] The method, apparatus, and ablation system for determining an ablation effect of an ablation system according to embodiments of the present application can obtain an effective ablation power, a contact state, and a safety limit maximum power, and use these to evaluate an ablation depth and ablation damage, thereby enabling an accurate evaluation of the ablation effect.

[0095] The foregoing is only a schematic specific embodiment of the present application. Without departing from the concept and principles of the present application, any equivalent changes and modifications made by any person skilled in the art shall fall within the scope of protection of the present application.

Claims

1. A device for predicting the ablation effect of an ablation system, the ablation system comprising a spherical catheter, a back plate and an energy release device, the spherical catheter comprising a catheter and a spherical head end arranged on the catheter, a plurality of electrodes arranged on the spherical head end, the spherical head end being abutted against human tissue to be ablated, the back plate being abutted against the surface of human skin, the energy release device being connected to the spherical catheter and the back plate respectively, and being used to provide ablation energy to the electrodes on the spherical catheter, the device comprising a memory and a processor coupled to the memory, the processor being configured to execute, based on instructions stored in the memory: Acquire a current overall loop impedance value from the plurality of electrodes through the human body to the back plate; Calculating the effective ablation power according to the current overall loop impedance value; and judging the ablation effect according to the effective ablation power, in, Calculating the effective ablation power according to the current overall loop impedance value includes: The effective ablation power is calculated by the following formula: ， in, is the effective ablation power, is the total ablation power delivered to the plurality of electrodes, is the current overall loop impedance value, is the first overall loop impedance value of the plurality of electrodes from the human body to the back plate when the spherical head end is completely in the human blood, It is the second overall loop impedance value of the multiple electrodes from the human body to the back plate when the spherical head end is completely wrapped by human tissue.

2. The device according to claim 1, characterized in that The processor is further configured to: Determining a current contact state between the spherical tip and human tissue; and The ablation effect is determined according to the abutment state.

3. The device according to claim 2, characterized in that Determining the sticking state includes: Obtaining the current impedance value of each electrode through the human body to the back plate; Determining the state of each electrode according to the current impedance value of each electrode from the human body to the back plate, the state includes a first state in which the electrode is in human blood and a second state in which the electrode is attached to human tissue, including: when the current impedance value is an impedance value of a first order of magnitude, judging that the electrode corresponding to the impedance value is in a first state, and when the current impedance value is an impedance value of a second order of magnitude, judging that the electrode corresponding to the impedance value is in a second state; and The sticking state is determined according to the state of each electrode.

4. The device according to claim 2, characterized in that Determining the sticking state further includes: Obtain the current impedance value between any two adjacent electrodes on the spherical head end, when the current impedance value between any two adjacent electrodes is [ -x, +x], indicating that the two adjacent electrodes are in good contact with the human tissue. in, is the surface area of ​​the spherical head, is the surface area occupied by any two adjacent electrodes, is the second overall loop impedance value of the multiple electrodes from the human body to the back plate when the spherical head end is completely wrapped by human tissue, and x is the allowable error value.

5. The device according to claim 2, characterized in that The processor is further configured to: The maximum ablation power currently allowed is determined by the following formula: ， in, is the maximum ablation power currently allowed, is the maximum safe power density of the energy release device, is the surface area of ​​the spherical head, It is the second overall loop impedance value of the multiple electrodes from the human body to the back plate when the spherical head end is completely wrapped by human tissue.

6. The device according to claim 5, characterized in that The processor is further configured to adjust the position of the spherical tip and / or provide recommended power parameters according to the effective ablation power and / or the abutment state and / or the currently allowed maximum ablation power.

7. The device according to claim 1, characterized in that The ablation effect includes ablation depth and ablation damage.

8. An ablation system, comprising: A spherical catheter, comprising a catheter and a spherical head end arranged on the catheter, a plurality of electrodes being arranged on the spherical head end, and the spherical head end being close to human tissue to be ablated; The back plate is attached to the surface of human skin; An energy release device, connected to the spherical catheter and the back electrode plate, respectively, for providing ablation energy to the electrodes on the spherical catheter; An impedance monitoring module, used to obtain a current overall loop impedance value from the plurality of electrodes through the human body to the back plate; an ablation damage assessment module, configured to calculate the effective ablation power according to the current overall loop impedance value, and determine the ablation effect according to the effective ablation power, Wherein, in calculating the effective ablation power according to the current overall loop impedance value, the ablation damage assessment module is used to calculate the effective ablation power by the following formula: ， in, is the effective ablation power, is the total ablation power delivered to the plurality of electrodes, is the current overall loop impedance value, is the first overall loop impedance value of the plurality of electrodes from the human body to the back plate when the spherical head end is completely in the human blood, It is the second overall loop impedance value of the multiple electrodes from the human body to the back plate when the spherical head end is completely wrapped by human tissue.

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