RU2771638C1 - Assessment of the development of ablation by the irreversible electroporation method based on the amplitude of measured biopolar signals - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions relates to medicine, namely, to a method for assessing the development of ablation with irreversible electroporation and to a system for implementation thereof. A pair of electrodes of an ablative catheter is therein connected to the target tissue. A first bipolar signal with a first amplitude is received from the pair of electrodes at the first stage of the ablation procedure. The reception at the first stage includes receiving the first bipolar signal before applying an irreversible electroporation (IRE) pulse to the target tissue. A second bipolar signal with a second amplitude is received from the pair of electrodes at the second stage of the ablation procedure. The reception at the second stage includes receiving the second bipolar signal after applying an IRE pulse to the target tissue. The effectiveness of the ablation procedure is assessed based on the first and second amplitudes. The effectiveness assessment involves displaying (i) a first numerical difference between the first and second amplitudes and/or (ii) a second numerical difference between the second amplitude and the target threshold value.

EFFECT: accurate indication of execution of ablation is provided due to the visual indication of the development of the ablation procedure at each site with optimisation of the amount of IRE pulses applied to the tissue, thus the safety of the method for the patient is increased and the cycle of the ablation procedure is shortened; displaying the value of difference between the measured amplitude and the threshold value provides a possibility of controlling the application of pulses to the corresponding pairs of electrodes to form uniform damage along the target tissue at the site of ablation; indication of the difference between the amplitudes measured on the same pair of electrodes provides a possibility of visualising the effectiveness and rate of development of ablation in the area measured by one pair of electrodes, compared with the area measured by another pair of electrodes.

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Description

Scope of the invention

The present invention relates per se to tissue ablation procedures, and in particular to methods and systems for estimating parameters in irreversible electroporation ablation procedures.

Prerequisites for the creation of the invention

Various techniques are known in the art for tracking the development of tissue ablation using this electrode.

For example, US Pat. No. 10,342,606 describes high frequency ablation of body tissue using a cooled high frequency electrode connected to a high frequency generator, including a computer graphics control system and an automatic controller to control the output of the generator, and configured to display a measured parameter related to the ablation process, on a graphic display in real time and visual tracking of the change in the output signal parameter controlled by the controller during the ablation process.

Statement of the Invention

In the exemplary embodiment of the present invention described herein, a method is provided, comprising bonding at least a pair of ablation catheter electrodes to a target tissue; in the first stage of the ablation procedure, a first bipolar signal having a first amplitude is received from a pair of electrodes; in the second stage of the ablation procedure, a second bipolar signal having a second amplitude is received from a pair of electrodes; assessing at least a parameter indicative of the progress of the ablation procedure based on the first and second amplitudes.

In some embodiments, parameter estimation includes displaying the first and second amplitudes on the same plot. In other embodiments, displaying the first and second amplitudes includes displaying a first bar indicating a first amplitude and a second bar indicating a second amplitude on the same graph. In other embodiments, the method includes receiving an additional first bipolar signal having an additional first amplitude and an additional second bipolar signal having an additional second amplitude from an additional pair of ablation catheter electrodes, and the method further comprising displaying an additional first bar indicating the additional first amplitude, and an additional second bar indicating an additional second amplitude on the same graph.

In one embodiment, a pair of electrodes is associated with a target tissue at a first site and an additional pair of electrodes is associated with a target tissue at a second site different from the first site, and the method includes applying to the target tissue: (i) a first irreversible electroporation (IRE) pulse at the first section and (ii) the second IRE pulse in the second section based on the same graph. In another embodiment, the application of the first and second IRE pulses involves the application of a first IRE pulse that is different from the second IRE pulse. In yet another embodiment, displaying the first and second amplitudes provides for displaying the first and second columns superimposed on each other.

In some embodiments, the first stage acquisition involves receiving a first bipolar signal before applying an irreversible electroporation (IRE) pulse to the target tissue, and the second stage receiving involves receiving a second bipolar signal after applying the IRE pulse to the target tissue. In other embodiments, the method includes checking if an additional IRE pulse is needed to the target tissue based on the estimated parameter, and if an additional IRE pulse is required, the method in the third step of the ablation procedure includes: (i) applying an additional IRE pulse to the target tissue based on the estimated parameter. parameter, (ii) receiving a third bipolar signal having a third amplitude from the pair of electrodes, and (iii) estimating at least the parameter based on the first and third amplitudes. In still other embodiments, parameter estimation includes displaying at least one of: (i) a first numerical difference between the first and second amplitudes, and (ii) a second numerical difference between the second amplitude and the target threshold.

In accordance with an embodiment of the present invention, a system including a processor and a display is further provided. The processor is configured to receive: (a) a first bipolar signal having a first amplitude in the first stage of the ablation procedure and (b) a second bipolar signal having a second amplitude in the second stage of the ablation procedure from at least a pair of ablation catheter electrodes associated with target tissue, and the processor is configured to estimate at least one parameter indicative of the progress of the ablation procedure based on the first and second amplitudes. The display is configured to display the parameter.

Brief description of graphic materials

The present invention will be better understood from the following detailed description of the exemplary embodiments, presented together with the following drawings.

On FIG. 1 is a schematic illustrative illustration of a position tracking system and an ablation system for irreversible electroporation in accordance with an exemplary embodiment of the present invention.

On FIG. 2 is a schematic pictorial illustration of a plot of the amplitudes displayed for estimating and monitoring one or more IRE ablation parameters in accordance with an embodiment of the present invention.

On FIG. 3 is a flowchart schematically illustrating a method for estimating one or more ablation parameters based on the amplitude of bipolar signals obtained during an IRE ablation procedure, in accordance with an exemplary embodiment of the present invention.

Detailed description of embodiments

general description

Irreversible electroporation (IRE) can be used, for example, to treat arrhythmia by ablation of tissue cells with high voltage pulses applied to the tissue. Cell destruction occurs when the transmembrane potential exceeds a threshold value, resulting in cell death and the formation of a lesion. In IRE-based ablation procedures, high voltage bipolar electrical pulses are applied to, for example, one or more pairs of electrodes in contact with the tissue to be ablated so as to form a lesion between the electrodes and thus treat the patient's cardiac arrhythmia.

Sometimes more than one set of bipolar electrical pulses, also referred to herein as IRE pulses, is required to form a lesion and thus complete an ablation procedure. Moreover, the lesion to be ablated may be heterogeneous, so different amounts of IRE pulses may need to be applied to tissue through different pairs of electrodes.

In principle, after the application of the IRE pulses, it is possible to measure the impedance between the electrodes of each pair, so as to receive an indication as to whether the ablation procedure should be completed or not. However, such impedance measurements may not provide a sufficiently accurate indication of the evolution of the ablation procedure.

In the exemplary embodiments of the present invention, which are described hereinafter, improved techniques are provided for evaluating one or more parameters related to the performance of an ablation procedure.

In some embodiments, a physician inserts an IRE ablation catheter into an ablation site having tissue to be ablated into a patient's heart. The ablation catheter contains one or more pairs of electrodes that are in contact with the heart tissue at the ablation site.

In some embodiments, the IRE ablation system comprises an IRE pulse generator (IPG), a switching unit that is configured to switch the power applied by the IPG to one or more selected pairs of electrodes, and a processor.

In some embodiments, at the first stage of the ablation procedure, for example, before applying the first set of one or more IRE pulses, the clinician may use a pair of electrodes to measure the first bipolar signal measured at a given tissue site at the ablation site. In the context of the present description and in the claims, the term "bipolar signal" refers to any acceptable signal, such as, without limitation, impedance. The bipolar signal is measured between two catheter electrodes or any other probe electrodes in the same area, such as the electrodes of the aforementioned pair. In the context of the present description and in the claims, the terms "IRE pulse" and "set of IRE pulses" are used interchangeably and refer to a set of one or more IRE pulses.

In some embodiments, in the second stage of the ablation procedure, for example, after application of the first IRE pulse, the clinician may use a pair of electrodes to measure the second bipolar signal measured at the site.

In some embodiments, the IRE ablation system comprises a processor that is configured to receive first and second bipolar signals from each pair of electrodes. The processor is configured to determine the first and second amplitudes, respectively, of the first and second bipolar signals received from each pair.

In some embodiments, the processor is configured to display a suitable graph, such as a histogram showing a visual comparison of the first and second amplitudes, for each pair of electrodes.

In some embodiments, the clinician may evaluate one or more parameters related to the development and effectiveness of the ablation procedure for each pair of electrodes based on the displayed amplitude plot. For example, the clinician may judge that the first IRE pulse is insufficient to generate the desired lesion at a given site based on the displayed amplitude plot. In this example, the clinician may use the IPG and the switch block to apply the second IRE pulse to the tissue only in that area.

Thanks to the described technologies, the physician can obtain a visual indication of the progress of ablation at each ablation site, for example, during an ablation procedure. Moreover, using the described technologies, it is possible to optimize the number of IRE pulses applied to the tissue, and thereby increase the safety of the method for the patient and reduce the cycle time of the ablation procedure.

System Description

On FIG. 1 is a schematic illustrative illustration of an irreversible electroporation (IRE) position tracking and ablation system 20 using a catheter 21, in accordance with an exemplary embodiment of the present invention.

In some embodiments, the system 20 includes a deflectable tip section 40 that is mounted on the distal end 22a of the shaft 22 of the catheter 21 with a deflectable tip section 40 containing a plurality of electrodes 50, as shown in inset 25.

In the exemplary embodiment described herein, the electrodes 50 are configured to sense intracardiac (IC) electrocardiographic (ECG) signals and can additionally be used for IRE ablation of left atrial tissue of the heart 26, such as IRE ablation of the pulmonary vein ostium 51 in the heart. 26. It should be noted that the technologies described herein are applicable, mutatis mutandis, to other regions (eg, atria or ventricles) of the heart 26 and to other organs of the patient 28.

In some embodiments, the proximal end of catheter 21 is connected to a control console 24 (also referred to herein as console 24) containing an ablation power source, in this example an IRE Pulse Generator (IPG) 45, which is configured to deliver peak power. in the range of tens of kW. The console 24 includes a switching unit 46 that is configured to switch the power supplied by the IPG 45 to one or more selected pairs of electrodes 50. The serial IRE ablation protocol may be stored in the memory 48 of the console 24.

In some embodiments, clinician 30 inserts distal end 22a of stem 22 through sheath 23 into heart 26 of patient 28 lying on table 29. Physician 30 directs distal end 22a of stem 22 to a target position in heart 26 by manipulating stem 22 with manipulator 32 near the proximal end of catheter 21 and/or deflection from sheath 23. During insertion of distal end 22a, sheath 23 holds deflectable tip section 40 in a straightened configuration. Due to the straightened configuration of the tip section 40, the sheath 23 also minimizes vascular injury when the clinician 30 moves the catheter 21 through the vasculature of the patient 28 to a target location, such as an ablation site in the heart 26.

Once the distal end 22a of shaft 22 reaches the ablation site, clinician 30 retracts sheath 23 and deflects handpiece section 40 and further brings electrodes 50 positioned above handpiece section 40 into contact with orifice 51 at the ablation site by acting on shaft 22. In the present example the ablation site contains the pulmonary vein, but in other embodiments, clinician 30 may choose any other acceptable ablation site.

In some embodiments, the electrodes 50 are connected by wires passing through the shaft 22 to the processor 41 configured to control the switching unit 46 of the interface circuits 44 in the console 24.

As further shown in inset 25, the distal end 22a includes a position sensor 39 of the position tracking system, which is associated with the distal end 22a, for example, on the section 40 of the handpiece. In the present example, position sensor 39 comprises a magnetic position sensor, but in other embodiments, any other acceptable type of position sensor (eg, other than magnetic) may be used. During navigation of the distal end 22a into the heart 26, the processor 41 of the console 24 receives signals from the magnetic position sensor 39 in response to magnetic fields from external field generators 36, for example, to determine the position of the tip section 40 in the heart 26 and optionally display the tracked position superimposed on the image of the heart 26, on the display 27 of the console 24. The magnetic field generators 36 are placed in known positions outside the body of the patient 28, for example under the table 29. The console 24 also contains a trigger circuit 34 configured to drive the magnetic field generators 36.

The method of determining the position using external magnetic fields is implemented in various medical systems, for example, in the CARTO™ system manufactured by Biosense Webster Inc. (Irvine, California) and is detailed in U.S. Patent Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, PCT Patent Publication WO 96/05768, and U.S. Patent Application Publication No. 2002/0065455 A1, 2003/0120150 A1 and 2004/0068178 A1, the disclosures of which are incorporated herein by reference in their entirety.

Typically, the processor 41 of the console 24 is a general purpose processor from a general purpose computer with an acceptable user interface and interface circuits 44 for receiving signals from the catheter 21, as well as for applying ablation energy through the catheter 21 in the left atrium of the heart 26 and for controlling other components system 20. Processor 41 typically contains software in memory 48 of system 20 that is programmed to perform the functions described herein. The software may be electronically downloaded to a computer, such as transmitted over a network, or in an alternative or additional embodiment, may be provided and/or stored on a non-transitory tangible medium such as a magnetic, optical, or electronic storage device.

Evaluation of the effectiveness and development of ablation performed by the method of irreversible electroporation

Irreversible electroporation (IRE), also referred to as pulsed field ablation (PFA), can be used as a minimally invasive therapeutic modality to generate damage (eg, kill tissue cells) at the ablation site by applying high voltage pulses to tissue. In the present example, IRE pulses can be used to kill cells in myocardial tissue to treat cardiac arrhythmias in the heart 26. Cell destruction occurs when the transmembrane potential exceeds a threshold, resulting in cell death and thus development of tissue damage. Therefore, of particular interest is the use of high voltage bipolar electrical pulses, for example, using a pair of electrodes 50 in contact with tissue at the ablation site, to generate strong electrical fields (for example, above a certain threshold value) to kill tissue cells located between the electrodes.

In the context of this description, a "bipolar" voltage pulse means a voltage pulse applied between the two electrodes 50 of the catheter 21 (as opposed to, for example, unipolar pulses, which are applied, for example, during radiofrequency ablation with a catheter electrode relative to some common ground electrode, not placed on the catheter).

In order to perform IRE ablation in a relatively large region of heart tissue 26, such as the circumference of the pulmonary vein (PV) or any other suitable organ, multiple pairs of electrodes 50 of a catheter 21 having a plurality of electrodes 50 in the deflectable tip section 40 must be used. To create as even a generated electric field as possible over a large area of tissue, it is best to choose pairs of electrodes 50 with overlapping fields, or at least fields adjacent to each other. However, there is a Joule heat component that occurs with the generated IRE fields, and this heating can damage the electrodes when multiple pairs of electrodes 50 are continuously used to drive the IRE pulse train.

In one embodiment, system 20 includes surface electrodes 38 as shown in the example of FIG. 1, attached by wires through cable 37 to the chest and shoulder of a patient 28. In some embodiments, surface electrodes 38 are configured to sense body surface (BTS) ECG signals in response to heart beats 26. Acquiring ECG Signals with BS can be carried out using conductive pads attached to the surface of the body, or any other acceptable technology. As shown in FIG. 1, surface electrodes 38 are attached to the chest and shoulder of patient 28, however, additional surface electrodes 38 may be attached to other organs of patient 28, such as limbs.

In some embodiments, electrodes 50 are configured to sense intracardiac (IC) ECG signals and (eg, at the same time) surface electrodes 38 sense IC ECG signals. In other embodiments, the sensing of the IC ECG signals may be sufficient to perform IRE ablation, so that the surface electrodes 38 may be used for other uses.

In some embodiments, clinician 30 may couple at least a pair of electrodes 50 to target tissue at an ablation site in heart 26. Target tissue is intended to be ablated by applying one or more IRE pulses via electrodes 50. It should be noted that IRE pulses can be applied to the target tissue multiple times, for example, at various stages of the IRE ablation procedure.

In some embodiments, prior to applying the first IRE pulse to the target tissue, referred to herein as the first stage of the IRE ablation procedure, clinician 30 may apply a pair of electrodes 50 to produce a bipolar signal, referred to herein as the first bipolar signal. In subsequent stages, such as the second and third stages of the IRE ablation procedure, after application of the first IRE pulse, clinician 30 may use a pair of electrodes 50 to obtain one or more subsequent bipolar signals, such as referred to herein as second and third bipolar signals, to control various parameters relating to the effectiveness and/or development of the IRE ablation procedure. In the present example, the term "second bipolar signal" refers to the bipolar signal received by the pair of electrodes after the application of the first IRE pulse to the target tissue, and the term "third bipolar signal" refers to the bipolar signal obtained after the application of the second, subsequent, IRE pulse to the target tissue. target tissue. In other embodiments, the first, second, and third steps may refer to any other steps in the IRE ablation procedure, and therefore the respective first, second, and third bipolar signals may be obtained at any other reasonable time, such as before, during, or after the application of the IRE. -impulses.

In some embodiments, processor 41 is configured to receive the aforementioned first and second (and optionally third) bipolar signals from electrodes 50 and hold the amplitude of the corresponding bipolar signal for each received bipolar signal. For example, during an IRE ablation procedure, processor 41 may hold (i) a first amplitude of a first bipolar signal (e.g., received by the electrodes 50 prior to delivery of the first IRE pulse to the target tissue), (ii) a second amplitude of the second bipolar signal (e.g., received by the electrodes 50 after the application of the first IRE pulse to the target tissue) and optionally (iii) a third amplitude of the third bipolar signal that can be received by the electrodes 50 after the optional application of the second IRE pulse to the target tissue.

In some embodiments, processor 41 is configured to estimate one or more parameters, such as, but not limited to, effectiveness and progression of IRE ablation, based on at least the first and second amplitudes.

In some embodiments, processor 41 is configured to display a graph having two or more of the above amplitudes, for example, on display 27. Such a graph is described in detail in FIG. 2 below.

This particular configuration of system 20 is shown by way of example to illustrate certain problems addressed by the exemplary embodiments of the present invention and to demonstrate the use of these exemplary embodiments to improve the performance of such an IRE ablation system. However, the embodiments of the present invention are in no way limited to this particular kind of exemplary system, and the principles described herein can be similarly applied to other kinds of ablation systems.

Amplitude display of multiple bipolar signals to monitor ablation parameters by irreversible electroporation.

On FIG. 2 is a schematic pictorial illustration of a graph 60 of amplitudes displayed for estimating and monitoring one or more IRE ablation parameters in accordance with an embodiment of the present invention. As described in FIG. 1 above, graph 60 may be displayed on display 27 or any other suitable display of system 20.

In some embodiments, graph 60 displays three bars 61, 64, and 67 indicating the amplitudes (measured in mV) of bipolar signals received from three respective pairs 1, 4, and 7 of electrodes 50 that clinician 30 has associated with (e.g., brought into contact with). c) the target tissue of the heart 26, for example, during the first and second stages of the IRE ablation procedure.

In the example shown in FIG. 2, bar 61 contains bars 62 and 63, overlapping each other, which indicate the amplitude of the bipolar signals measured between the electrodes 50 of pair 1. Bar 62 indicates the amplitude of the bipolar signal obtained before the application of IRE ablation pulses to the target tissue, also referred to as herein the first bipolar signal. Similarly, column 63 indicates the amplitude of the bipolar signal obtained after the application of the last ablation pulses to the target tissue, also referred to herein as the second bipolar signal. Likewise bar 64 includes bars 65 and 66 overlapping each other which indicate the amplitude of the bipolar signals respectively measured in the aforementioned first and second steps of the IRE ablation procedure between the electrodes 50 of the pair 4 of electrodes. In addition, the column 67 contains columns 68 and 69, overlapping each other, which indicate the amplitude of the bipolar signals, respectively measured in the aforementioned first and second stages of the IRE ablation procedure, between the electrodes 50 of the pair 7 of electrodes.

In some embodiments, processor 41 is configured to assist clinician 30 in estimating one or more parameters related to the development of an IRE ablation performed at cardiac ablation site 26 based on columns 61, 64, and 67 of plot 60. For example, based on plot 60 clinician 30 can evaluate the effectiveness of IRE ablation and the need to use IPG 45 (and switch block 46) to apply additional IRE pulses, also referred to herein as a second IRE pulse, to one or more specific pairs of electrodes 50 in order to improve the outcome of the IRE procedure. -ablation. In other embodiments, processor 41 is configured to control IPG 45 (and switch block 46) to apply additional IRE pulses to one or more specific pairs of electrodes 50. Note that columns 62, 65, and 68 indicate the amplitude of the bipolar signal measured before the application of IRE pulses to the target tissue, and columns 63, 66 and 69 indicate the amplitude of the bipolar signal measured after the application (for example, the first set) of IRE pulses to the target tissue.

In some embodiments, clinician 30 can evaluate the development of IRE ablation in the respective area being ablated by displaying the difference between amplitudes measured on the same pair of electrodes. In the example shown in FIG. 2, the difference between bars 68 and 69 of bar 67 is greater than the difference between bars 65 and 66 of bar 64. It should be noted that the amplitudes shown as bars 64 and 67 are measured at the respective electrode pairs 4 and 7, and bars 64 and 67 generates processor 41. In bars 64 and 67, clinician 30 can see that in the area measured by electrode pair 7 (compared to the area measured by electrode pair 4), ablation efficiency is greater and ablation progresses faster.

In alternative embodiments, instead of displaying graph 60, processor 41 is configured to display a percent reduction in signal amplitude. For example, processor 41 may display the amplitude of the bipolar signals measured between electrodes 50 before ablation of the target tissue as 100%, and after application of one or more IRE pulses, processor 41 may display the remaining percentage or amount of percentage reduction. In the example shown in FIG. 2, in electrode pair 1, processor 41 may display a numerical value such as a 35% reduction instead of the difference between bands 62 and 63, and in electrode pair 7, processor 41 may display 70%, which corresponds to the difference (percentage) between bars 68. and 69. As used herein and in the claims, the term "percent reduction" may refer to any display of the numerical difference between the measured amplitude before and after the application of one or more IRE pulses.

In other embodiments, processor 41 is configured to display an amplitude threshold level that indicates that there is a sufficient number of IRE pulses applied to the respective pair of electrodes. In the example shown in FIG. 2, the threshold value may be greater than the amplitude displayed on bar 69 and less than the amplitude displayed on bars 63 and 66. In other words, it is not necessary to apply additional IRE pulses to the electrode pair 7, but to form a lesion, it is required to apply an additional one or more than IRE pulses via electrode pairs 1 and 4. Moreover, based on columns 63 and 66, clinician 30 or processor 41 can control IPG 45 to apply various sets of additional one or more IRE pulses to electrode pairs 1 and 4 so as to generate a uniform lesion along the target tissue at the ablation site. For example, a first additional IRE pulse, having a specific energy and a specific duration, can be applied to the target tissue via a pair of 4 electrodes, and a second additional IRE pulse, having, for example, higher energy and/or longer duration, can be applied to the target tissue. tissue via a pair of 1 electrodes, or simply by repeating the same ablation on a subset of electrodes.

In other embodiments, the processor 41 is configured to set a threshold value for each pair of electrodes (or a common threshold value for all pairs of electrodes) and display (i) the measured amplitude level in relation to the threshold value (for example, using a graphical display) or a numeric value (also referred to herein as a numerical difference) indicating the arithmetic difference between the threshold value and the measured amplitude level, after the application of one or more IRE pulses. For example, the amplitude before application of the IRE pulses may be 1 mV or 2 mV, however, if after the application of the first set of one or more IRE pulses the measured amplitude is less than 0.1 mV, there is no need to apply additional IRE pulses to corresponding pair of electrodes. In other words, it is important to display how much the measured amplitude differs from the threshold value.

This particular graph configuration 60 is shown as an example to illustrate certain problems solved in the embodiments of the present invention and to demonstrate the use of these embodiments to improve the efficiency of the ablation system. However, the embodiments of the present invention are in no way limited to this particular type of illustrative graph, and the principles described herein can be similarly applied to other types of graphs to improve the estimation of ablation parameters during and after IRE or any other type of ablation procedure. In other embodiments, instead of plot 60 or in addition to it, the measured amplitudes can be displayed using adjacent (rather than superimposed) bars or using any other acceptable type of plot, such as, without limitation, a scatterplot, so as to evaluate one or more parameters indicating the progress of the ablation procedure. Moreover, physician 30 may select to display one or more types of graphs from a list displayed on display 27. In some embodiments, processor 41 may hold additional bipolar signals measured at the same location in time, processor 41 is configured to display a comparison between a plurality (eg, more than two) of measured amplitudes in response to a command from clinician 30 so that clinician 30 can evaluate the progress of the IRE ablation.

In some embodiments, in the third stage of the ablation procedure following the application of an additional IRE pulse to the target tissue, the processor 41 is configured to receive a measurement of a third bipolar signal having a third amplitude from the corresponding pair of electrodes. The processor 41 is configured to estimate one or more parameters indicative of the progress of the ablation procedure based on the first amplitude (which was obtained by the pair of electrodes before the application of the first IRE pulse) and the third amplitude obtained in the third stage.

On FIG. 3 is a flowchart schematically illustrating a method for evaluating bipolar signals obtained during an IRE ablation procedure, one or more parameters indicative of the progress of an ablation procedure, based on amplitude, in accordance with an exemplary embodiment of the present invention.

The method begins with the catheter insertion step 100, in which the clinician 30 inserts the IRE catheter 21 into the ablation site in the patient's heart 26 and brings one or more pairs of electrodes 50 into contact with the target tissue of the heart 26. As described above in FIG. 1, by associating one or more pairs of electrodes 50 with target tissue in heart 26, catheter 21 is configured to perform IRE ablation by applying one or more IRE pulses generated by IPG 45 to target tissue.

The following description refers to one pair of electrodes 50, but also applies to multiple pairs of electrodes 50, as shown, for example, in FIG. 2 above.

In the first ablation step 102, the processor 41 receives a first (eg, pre-ablative) bipolar signal having a first amplitude from a pair of electrodes 50 in the first stage of the ablation procedure, eg, prior to applying the IRE pulses to the target tissue. In the second ablation step 104, the clinician 30 applies the catheter 21 to apply the first IRE pulse to the target tissue. Upon application of the first IRE pulse, processor 41 receives a subsequent (eg, second) bipolar signal having a subsequent (eg, second) amplitude from the pair of electrodes 50. It should be noted that the second bipolar signal is measured between the pair of electrodes 50 at the ablation site after application of the first IRE pulse to the target tissue.

In the evaluation step 106, the processor 41 evaluates or assists the clinician 30 in evaluating at least a parameter indicative of the progress of the ablation procedure, such as the effectiveness of IRE ablation, for example, by displaying the first and second amplitudes on the graph 60. In the decision step 108, the processor 41 and/ or the physician 30 checks if the parameter has reached the target threshold. The term "target threshold" may refer to a numerical threshold or the ratio or difference between the first and second amplitudes. In some embodiments, clinician 30 may check whether a parameter has reached a target threshold by visual comparison, such as by comparing bars 62 and 63.

If the parameter has not yet reached the target threshold, the method returns to step 104 to apply a second IRE pulse, followed by obtaining a third bipolar signal having a third amplitude and evaluating if the third amplitude has reached the target threshold at steps 106 and 108.

At the end of procedure step 110, if the parameter has reached the target threshold, for example, after applying any acceptable number of IRE ablation pulses, the clinician 30 ends the IRE ablation procedure and removes the catheter 21 from the patient's heart 26.

In some cases, after performing the cycle consisting of steps 104, 106 and 108, several times the parameter indicating the progress of the ablation procedure may not reach the target threshold. Thus, in other embodiments, processor 41 may prompt clinician 30 to apply a set of one or more additional radiofrequency (RF) ablation pulses to target tissue using catheter 21 or any other suitable catheter that is capable of performing RF ablation procedures.

While the embodiments described herein are primarily concerned with improving irreversible electroporation (IRE) ablation procedures, the methods and systems described herein can also be applied to other applications, such as any other ablation procedure such as, without restrictions, RF ablation applied to any acceptable organ of the patient 28.

Thus, it should be understood that the above-described exemplary embodiments are provided by way of example only, and that the present invention is not limited specifically to those depicted and described above herein. On the contrary, the scope of the present invention includes both combinations and subcombinations of the various features described above, as well as variations and modifications thereof, which will be apparent to those skilled in the art upon reading the above description and which have not been described in the prior art. Documents incorporated into this patent application by reference are to be considered an integral part of the application, except that if the definitions of terms in those incorporated documents conflict with definitions made explicitly or implicitly in the present description, only the definitions of the present description should be considered.

Claims (24)

1. A method for assessing the development of ablation with irreversible electroporation, wherein the method includes the steps of: linking at least a pair of electrodes of the ablative catheter to the target tissue; receiving a first bipolar signal having a first amplitude from a pair of electrodes in a first step of the ablation procedure, the first step receiving the first bipolar signal before applying an irreversible electroporation (IRE) pulse to the target tissue; receiving a second bipolar signal having a second amplitude from a pair of electrodes in a second stage of the ablation procedure, the second stage receiving comprising receiving a second bipolar signal after applying the IRE pulse to the target tissue; and evaluate the effectiveness of the ablation procedure, based on the first and second amplitudes, and the performance evaluation includes displaying at least one of: (i) a first numerical difference between the first and second amplitudes, and (ii) a second numerical difference between the second amplitude and the target threshold. 2. The method of claim. 1, wherein the performance evaluation involves displaying the first and second amplitudes on the same graph. 3. The method of claim 2, wherein displaying the first and second amplitudes includes displaying a first bar indicating a first amplitude and a second bar indicating a second amplitude on the same graph. 4. The method of claim 3, comprising receiving an additional first bipolar signal having an additional first amplitude and an additional second bipolar signal having an additional second amplitude from an additional pair of ablation catheter electrodes, and comprising displaying an additional first bar indicating the additional first amplitude, and an additional second bar indicating an additional second amplitude on the same graph. 5. The method of claim 4, wherein a pair of electrodes is associated with a target tissue at a first site and an additional pair of electrodes is associated with a target tissue at a second site different from the first site, and comprising applying to the target tissue: (i) a first pulse of irreversible electroporation (IRE) in the first section and (ii) a second IRE pulse in the second section based on the same graph. 6. The method of claim 5, wherein applying the first and second IRE pulses includes applying a first IRE pulse that is different from the second IRE pulse. 7. The method of claim 3, wherein displaying the first and second amplitudes includes displaying the first and second bars superimposed on each other. 8. The method of claim. 1, including checking the need to apply an additional IRE pulse to the target tissue based on the estimated effectiveness, and in this case, if an additional IRE pulse is required, the method in the third stage of the ablation procedure includes the steps of: (i ) applying an additional IRE pulse to the target tissue based on the estimated efficiency, (ii) receiving a third bipolar signal having a third amplitude from the pair of electrodes, and (iii) evaluating the ablation efficiency based on the first and third amplitudes. 9. A system for assessing the development of ablation with irreversible electroporation, containing: a processor that is configured to receive from at least a pair of ablation catheter electrodes associated with the target tissue: (a) a first bipolar signal having a first amplitude in a first stage of the ablation procedure, the first stage receiving comprising receiving a first bipolar signal prior to application an irreversible electroporation (IRE) pulse to the target tissue, and (b) a second bipolar signal having a second amplitude, in the second stage of the ablation procedure, from at least a pair of ablation catheter electrodes associated with the target tissue, wherein the reception in the second stage involves the reception of a second bipolar signal after the application of the IRE pulse to the target tissue, and the processor is configured to evaluate the effectiveness of the ablation procedure, based on the first and second amplitudes, and performance evaluation includes displaying on the display at least one of: (i) a first numerical difference between the first and second amplitudes and (ii) a second numerical difference between the second amplitude and the target threshold; and a display that is configured to display the efficiency. 10. The system of claim 9, wherein the processor is configured to display the first and second amplitudes on the same graph to evaluate performance. 11. The system of claim 10, wherein the processor is configured to display a first bar indicating a first amplitude and a second bar indicating a second amplitude on the same graph. 12. The system of claim 11, wherein the processor is configured to receive an additional first bipolar signal having an additional first amplitude and an additional second bipolar signal having an additional second amplitude from an additional pair of ablation catheter electrodes and displaying an additional first bar indicating an additional a first amplitude, and an additional second bar indicating an additional second amplitude, on the same graph. 13. The system of claim. 12, in which a pair of electrodes is associated with the target tissue at the first site, and an additional pair of electrodes is associated with the target tissue at a second site, different from the first site, and the processor is configured to control the pulse generator for application to target tissue: (i) a first irreversible electroporation (IRE) pulse at a first site and (ii) a second IRE pulse at a second site based on the same graph. 14. The system of claim. 13, in which the processor is configured to control the pulse generator to apply the first and second IRE pulses that are different from each other. 15. The system of claim 11, wherein the processor is configured to display superimposed first and second bars. 16. The system of claim. 11, in which the processor is configured to check the need to apply an additional IRE pulse to the target tissue based on the estimated effectiveness, and at the same time, if an additional IRE pulse is required, in the third stage of the ablation procedure, the processor is configured to: (i) applying an additional IRE pulse to the target tissue based on the estimated efficacy, (ii) receiving a third bipolar signal having a third amplitude from the pair of electrodes, and (iii) estimating the ablation efficacy based on the first and third amplitudes.

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