Method for detecting cardiac isolation status of a measurement location in the presence of far-field interference - Patents.com

Abstract

The present invention relates to a method for determining a cardiac isolation status of a measurement location (1) in the presence of far-field interference by analyzing a multi-channel intracardiac electrogram (2) of the measurement location (1) via a control system (3), wherein in an identification routine (9), the control system (3) applies an activation search algorithm to an analysis window (10) of at least 400 ms in at least two different channels (11) of the intracardiac electrogram (2), where the activation search algorithm identifies a window (W) of local activation potentials (12) within the analysis window (10), and in a classification routine (15), the control system (3) analyzes the local activation potentials (12) to determine the cardiac isolation status of the measurement location (1).

Description

[Technical field]

[0001] The invention relates to a method for determining a cardiac isolation state of a measurement location in the presence of far-field interference as claimed in claim 1 and to a control system adapted to carry out said method as claimed in claim 15.

[0002] The method particularly relates to atrial fibrillation and atrial flutter. Electrically, atrial fibrillation is the unregulated activation of atrial myocytes. During atrial fibrillation, the atria contribute only minimally to the function of the heart. Thus, atrial fibrillation reduces cardiac output but does not pose an imminent danger. However, when chronic, atrial fibrillation correlates with increased morbidity and mortality. One of the treatment options for atrial fibrillation is ablation therapy. Ablation is the destruction of cells that allows re-entry of electrical waves to reduce the unregulated activation of atrial myocytes. [Background technology]

[0003] Recommended treatments for atrial fibrillation include pulmonary vein isolation, which can be performed with a variety of ablation techniques, including radiofrequency ablation, cryoballoon ablation, and pulsed electric field ablation. Although energy is applied in different forms in these techniques, their common endpoint is to isolate the electrical activation of the pulmonary veins from the rest of the atrium.

[0004] In general, ablation therapy is successful when the target site is electrically isolated from the rest of the heart. There are various methods to assess the success of ablation therapy. These include costly 3D mapping of the ablation point as well as force or temperature measurements during ablation and electrogram analysis.

[0005] One known method (EP 3139828) focuses on the morphological analysis of the local activation potentials of the measurement location. In this method, the local activation potentials are classified into groups according to the number and characteristics of their peaks. Analysis of the potential distribution across the morphological groups allows a good classification of the cardiac isolation status of the measurement location. Methods based on electrical signals are cheap to implement and easily available. Furthermore, the measurement of electrical waves targets the actual physical effects underlying atrial fibrillation and not secondary factors.

[0006] The known method provides good results. However, in the known method, the local activation potential of the measurement location is detected based on the detection of a reference CS potential. Such a CS potential is detected by a coronary sinus catheter. Based on the reference CS potential, a predetermined window of about 200 ms is selected. The window here is defined as including the local activation potential of the channel associated with the measurement location. Therefore, the reliability of the known method relies on the patient being in sinus rhythm.

[0007] There is a need for a method of determining isolation using electrograms and analysis of local activation potentials that can be used without a priori knowledge of the location of the local activation potential from a reference potential. This would be necessary, for example, if a patient's cardiac isolation status is to be determined while the patient is experiencing atrial fibrillation. During atrial fibrillation, the temporal relationship between CS potentials and local activation can be disrupted. Although means exist that can defibrillate a patient into normal sinus rhythm, this is not always desirable.

[0008] A further problem is that the ECG contains not only local activation potentials but also far-field interference. Measurement of CS potentials typically requires a separate CS catheter in addition to the catheter that can be placed in the pulmonary vein. It would be desirable to identify a method of determining cardiac isolation that is feasible using a single catheter. Summary of the Invention [Problem to be solved by the invention]

[0009] It is therefore an object of the present invention to provide a method for detecting myocardial isolation in the presence of far-field interference that can be used in cases where it is not possible to rely on a reference CS potential to detect local activation. [Means for solving the problem]

[0010] The above mentioned problem is solved by a method according to claim 1.

[0011] In a primary implementation of the present invention, rather than using a single time window acquired for all channels, multiple channels of an intracardiac electrogram are analyzed independently to search for local activation potentials on the channels, thereby finding sufficient actual local activation potentials even during atrial fibrillation that can be analyzed to determine the cardiac isolation status of the measurement location.

[0012] In particular, this allows the cardiac isolation status of the measurement location to be determined during atrial fibrillation.

[0013] In particular, a method is proposed for determining the cardiac isolation status of a measurement location in the presence of far-field interference by analyzing a multi-channel intracardiac electrogram of the measurement location via a control system, wherein in an identification routine, the control system applies an activation search algorithm to an analysis window of at least 400 ms in at least two different channels of the intracardiac electrogram, where the activation search algorithm identifies windows of local activation potentials within the analysis window, and in a classification routine, the control system analyzes the local activation potentials to determine the cardiac isolation status of the measurement location.

[0014] Claim 2 defines a highly preferred application of the proposed method: in particular during atrial fibrillation or atrial flutter, local activation potentials, in particular local activation potentials of the pulmonary veins, cannot be detected relying on a priori knowledge of their time position from the reference potential CS potential.

[0015] In one embodiment as claimed in claim 3, in the classification routine, the control system analyses the morphology of the local activation potentials to determine the cardiac isolation state. It has been found that the morphological classification of the local activation potentials can be effectively performed even during atrial fibrillation. Claim 4 defines preferred details of the classification routine. In general, morphologies with a small number of fractionated peaks, morphologies with low peak frequencies, morphologies with low peak sharpness, and morphologies with small amplitudes indicate successful isolation. Claim 5 relates to a group of various preferred morphologies that have been found to enable successful determination of the isolation state.

[0016] The embodiment of claim 6 relates to a preferred analysis window width selected to ensure that at least one physiological local activation potential is primarily present within each analysis window. The width of the analysis window is preferably selected such that at least one physiological local activation potential is present within each analysis window. This allows the activation search algorithm to be adapted so that it is always able to find a local activation potential, since the analysis window contains at least one local activation potential. The algorithm does not need to find all local activation potentials. However, in an embodiment of claim 7, a sliding window is used to find multiple local activation potentials per channel.

[0017] Claim 8 relates to a means of verifying the success of the ablation procedure using the proposed method. Since the ablation procedure is an invasive surgical procedure, it is not preferable to observe the patient for several days to determine the success of the ablation procedure. Instead, the success of the ablation procedure should be determined during the intervention.

[0018] The activation search algorithm may include a peak detection algorithm as claimed in claim 9.

[0019] The control system can identify a fixed number of local activation potentials per channel (claim 10). The number can be equal to or less than the number of physiologically present local activation potentials. In this way, the number of erroneously identified local activation potentials can be reduced.

[0020] In a preferred embodiment according to claim 11, the control system performs an interference signal removal step before the identification step, in particular removing far-field interference signals. Claim 11 lists removal of pacing artifacts, CS potentials and signals around the ECG waves and / or related to them. By removing time windows related to far-field interference sources, the chance of detecting real local activation potentials is significantly increased. Such removal is called blanking. Blanking here can also be performed by weighting, so as to be able to identify local activation potentials that partially overlap the blanking time frame. Blanking can be weighted, for example, by a Gaussian curve that completely or almost completely removes the electrogram in the center of the time window to be blanked and only reduces the amplitude at the edges. Further details of weighted blanking are the subject of claim 12.

[0021] To reduce the number of falsely identified local activation potentials, the control system can perform a quality control step as claimed in claim 13. Sections of electrograms or even channels of electrograms can be excluded from consideration before or after the identification step based on quality parameters.

[0022] Claim 14 relates to the preferred catheter used.

[0023] Another teaching of equal importance, claimed in claim 15, relates to a control system arranged to carry out the proposed method. All statements made with respect to the proposed method are fully applicable.

[0024] An embodiment of the present invention will now be described with reference to the drawings, in which: [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 shows the proposed control system during the measurement of multi-channel intracardiac electrograms. [Diagram 2] FIG. 1 illustrates the proposed method in an exemplary application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The proposed method is used to determine the cardiac isolation status of the measurement location 1 in the presence of far-field interference by analyzing the multi-channel intracardiac electrogram 2 of the measurement location 1 via a control system 3. The cardiac isolation status may be a binary yes / no decision or a percentage of the isolation probability of the measurement location 1. The multi-channel intracardiac electrogram 2 is preferably measured by an intracardiac catheter 4 including multiple electrodes 5, for example 10 electrodes 5. These electrodes 5 have a certain spatial extent. Thus, the measurement location 1 also has a certain spatial extent. However, it is not necessary that all electrodes 5 of the measurement catheter 6 are located at the measurement location 1. For example, it may be the case that the measurement catheter 6 is positioned to cross the border of the lesion 7 to be ablated.

[0027] 1, the control system 3 may be a local unit 8 with a processor, possibly a user interface, etc. In one embodiment, the control system 3 may also include a cloud processor. Thus, the control system 3 need not be limited to a single device.

[0028] In the identification routine 9, the control system 3 applies an activation search algorithm over an analysis window 10 of at least 400 ms in at least two different channels 11 of the intracardiac electrogram 2. A channel 11 is defined as a measurement between at least two electrodes 5. The proposed method helps to determine a cardiac isolation state when the location of a local activation potential 12 relative to a reference CS potential 13 cannot be reliably obtained. This is especially true during atrial fibrillation.

[0029] The activation search algorithm identifies windows W of local activation potentials 12 within the analysis window 10. It is important that the windows W of local activation potentials 12 here can differ in terms of their time position between the channels 11 and are not set equally for all channels 11 in terms of the timing of the reference potential 14. The search field of these windows W is therefore selected to be at least 400 ms wide. In general, the windows W of local activation potentials 12 should include all or most of the relevant waveform of each local activation potential 12. The activation search algorithm may be an algorithm that directly searches for the windows W or an algorithm that searches for a single time point assigned to a local activation potential 12, from which the windows W are derived.

[0030] By searching for local activation potentials 12 without a reference timing, it is possible to determine a cardiac isolation state without any known reference timing.

[0031] 2 shows the application of the discrimination routine 9 to the multi-channel intracardiac electrogram 2 and the resulting window W of local activation potentials 12. In this case, preferably, the window W of local activation potentials 12 has a width of at most 250 ms, preferably at most 200 ms, more preferably at most 175 ms, more preferably at most 150 ms. Here, the window W has a width of about 128 ms. Preferably, the width of the window W of local activation potentials 12 is at least 50 ms.

[0032] In a classification routine 15, the control system 3 analyzes the local activation potentials 12 to determine the cardiac isolation status of the measurement location 1. The classification routine 15 may use the algorithm of EP 3139828 B1, which is incorporated herein by reference.

[0033] As mentioned above, preferably the intracardiac electrogram 2 was recorded during an atrial arrhythmia, in particular during atrial fibrillation or atrial flutter, the proposed method being able to determine a cardiac isolation state even in such cases.

[0034] As shown diagrammatically in Fig. 1, the measurement location 1 may be located at least partially inside the atrium 16, in particular inside the left atrium 16. The measurement location 1 may be an island 17 in the wall 18 of the left atrium 16 or an island 17 at the entrance of a pulmonary vein 19. There are various locations that may be targeted for ablation. The main target is the entrance of the pulmonary vein 19 to the left atrium 16. Effective isolation of the pulmonary vein 19 may be targeted for an ablation treatment. Thus, the measurement location 1 may be located at least partially inside the pulmonary vein 19.

[0035] In general, the proposed method can be used before, during and / or after an ablation treatment. It can be used to determine the isolation status of a potential target of ablation, in this case the isolation status can include information about how the measurement location 1 is involved in the conduction of electrical activation. In this case, preferably the cardiac isolation status includes information about how well the ablation treatment isolates the measurement location 1 from the rest of the heart. In this case, preferably the proposed method is used during and / or after an ablation treatment. In this case the measurement location 1 can be a target of an ongoing or completed ablation treatment.

[0036] Moving to the classification routine 15, it may be the case that the control system 3 analyzes the morphology of the local activation potential 12 to determine the cardiac isolation state of the measurement location 1. It has been found that information regarding the isolation state is contained in the complexity and amplitude of the local activation potential 12. The morphology of the local activation potential 12 depends on whether it is caused by the propagation of global cardiac activation or a local pacing event, and whether the global electrical situation is chaotic, as is the case with atrial fibrillation.

[0037] In the classification routine 15, the control system 3 can classify the local activation potentials 12 into morphological groups 20 and preferably determine the cardiac isolation state based on the distribution of the local activation potentials 12 across the groups. This is particularly advantageous as it allows ignoring erroneous detections of erroneous identification of local activation potentials 12, which may be caused by noise or far-field interference, since these erroneous detections often exhibit a morphology that is distinct from the morphology of local activation potentials 12 originating from non-isolated or isolated locations.

[0038] The control system 3 can classify the local activation potential 12 into a morphological group 20 based on the number of characteristic peaks of the local activation potential 12. For this, it is not necessary to count all plateaus in the electrogram 2 as characteristic peaks. Preferably, the control system 3 classifies as characteristic peaks at least peaks having a predetermined amplitude and / or peaks having at least a predetermined slope and / or peaks having at most a predetermined slope and / or peaks having at least a predetermined minimum peak distance and / or peaks having at most a predetermined maximum peak distance based on the peak morphology, in particular based on the minimum peak angle and / or the maximum peak angle. The classification as characteristic peaks can also be based on peaks having a predetermined peak frequency and / or peaks having a predetermined peak sharpness.

[0039] In this case, preferably, the morphology group 20 includes groups of local activation potentials 12 having a single characteristic peak or "monophasic 21" and / or groups of local activation potentials 12 having exactly two characteristic peaks or "biphasic 22" and / or exactly three characteristic peaks or "triphasic 23" and / or four or more characteristic peaks or "multiphasic 24". The morphology group 20 may also or alternatively include groups of local activation potentials 12 having at least two characteristic peaks or "double potentials 25" separated by a predetermined time. These may further include groups of local activation potentials 12 exhibiting morphologies associated with local activation potentials 12 that have been erroneously detected, for example, due to either noise or far-field interference.

[0040] Preferably, the analysis window 10 is selected so as to ensure or ensure the presence of at least one physiological local activation potential 12. For this purpose, the analysis window 10 may have a width of at least 400 ms, preferably at least 800 ms, more preferably at least 1.25 s. In a preferred embodiment, the analysis window 10 may have a width of at most 3 s, preferably at most 2 s, more preferably at most 1.75 s. Here, the width of the analysis window 10 is 1.5 s.

[0041] Preferably, multiple local activation potentials 12 are extracted from each channel 11 to allow a good statistical analysis of the local activation potentials 12, in particular their morphology groups 20. In this case, preferably, a total of at least two, preferably at least five, in particular at most ten local activation potentials 12 are extracted. To extract multiple local activation potentials 12 per channel, the analysis window 10 may be a sliding window that overlaps or does not overlap over the measurement time for each channel. Preferably, at least two local activation potentials 12 are extracted per channel 11, in particular here at least one local activation potential 12 can be extracted per analysis window 10. The measurement time can be selected to be at least 1 s, preferably at least 2.5 s, more preferably at least 5 s. The measurement time can be selected to be at most 10 s.

[0042] As mentioned above, the control system 3 can perform an identification routine 9 and a classification routine 15 on the multi-channel intracardiac electrograms 2 of the measurement location 1 recorded after an ablation procedure applied in the vicinity of, and in particular around, the measurement location 1 in order to determine the cardiac isolation status of the measurement location 1. This allows the control system 3 to assess the success of the ablation procedure.

[0043] Preferably, a comparison of data before and after the ablation procedure may be performed. Thus, the control system 3 may additionally perform at least a discrimination routine 9 on the multi-channel intracardiac electrograms 2 of the measurement locations 1 recorded before the ablation procedure, and determine the cardiac isolation state based on a comparison of the local activation potentials 12 before and after the ablation procedure. The measurement locations 1 before and after the ablation procedure do not need to be exactly the same, a reasonable degree of agreement may be sufficient.

[0044] The activation search algorithm may include a peak detection algorithm to find the local activation potential 12 and then find a window W of the local activation potential 12. The peak detection algorithm may be based on a non-linear filter, in particular a wavelet filter, and / or on a transformation of the electrogram 2, in particular a wavelet transform. The peak detection algorithm may include peak detection by amplitude. For example, the maximum amplitude within a given time frame may be detected as a peak.

[0045] Returning to the detection of local activation potentials 12 by considering their frequency under physiological conditions, in the identification routine 9 the control system 3 can identify a fixed number of local activation potentials 12 per channel 11 and / or per analysis window 10. Preferably, in the identification routine 9 the control system 3 can identify a fixed number of local activation potentials 12 per time interval. The time interval can be a measurement window. The fixed number can be based on the physiological heart rate and / or the measured heart rate. The fixed number can be at most one local activation potential 12 at least every 500 ms, preferably at most one at least every 800 ms, more preferably at most one at least every 1 s. Only detecting a single local activation potential 12 within any given time window, for example 800 ms, can ensure that the activation search algorithm always has the means to find a real local activation potential 12.

[0046] The rejection of interference signals, particularly due to far-field interference, will be explained in more detail with reference to Fig. 2. The control system 3 may perform an interference signal rejection step before the identification step. The interference signal rejection step may include a complete or weighted blanking of time intervals 26 around and / or relative to pacing artifacts and / or CS potentials 13 and / or ECG waves 27. The ECG waves 27 include P waves, QRS waves and / or T waves that may be associated with atrial and ventricular activity. In general, other artifacts may also be blanked. Such a weighted form of blanking is illustrated in Fig. 2.

[0047] In a simple embodiment, blanking can be seen as removing a part of the electrogram 2 or multiplying the corresponding part of the electrogram 2 by zero. In this case, blanking is preferably applied to all channels 11. In a weighted form, the blanking time interval 26 of the electrogram 2 is not fully multiplied by zero. In particular, only the amplitude may be reduced at and near the edges of the time interval 26, where far-field interference is expected to be less significant. This allows finding local activation potentials 12 that partially overlap the blanking time interval 26.

[0048] Pacing artifacts and / or CS potentials 13 and / or ECG waves 27 may be detected on electrograms 2 other than the multi-channel intracardiac electrograms 2, which may be coronary sinus or surface electrograms 2. These are generally better suited to identifying CS potentials 13 and ECG waves 27, such as P-waves, QRS-waves and T-waves, associated with atrial and ventricular activation than electrograms 2 of potentially isolated pulmonary veins 19.

[0049] The CS potentials 13 and ECG waves 27 can be detected by known algorithms, for example by using peak detection of the surface potential diagram 2. Pacing artifacts can be detected by peak amplitude detection and / or gradient analysis.

[0050] As part of the interference signal removal step or as an independent step, classification of interference signals can be performed and used for blanking of said interference signals, preferably classified as at least one of pacing artifacts and / or far-field interference and / or unstable activation potentials and / or activation potentials with noise. Detected interference signals can be excluded from those identified as local activation potentials 12.

[0051] Pacing artifacts are signals generated by methods of cardiac pacing. They can be classified by analyzing the voltage characteristics, particularly the slopes, of the channels 11. The local activation potentials 12 indicate the physiological delay between each channel 11 and the actual location associated with that channel. Thus, the control system 3 can classify signals occurring within a predefined short time window in many or all of the channels 11 as pacing artifacts. Alternatively, the control system 3 may have an input for external pacing timing.

[0052] Far-field interference can be classified by determining the timing of QRS activation from a surface ECG, for example, by depicting the ECG at P waves, QRS waves and / or T waves, where each wave can be associated with activation of a particular atrium or ventricle.

[0053] Unstable activation potentials may be activation potentials with poorly localized energy, baseline deviations and / or large wave-to-wave amplitude deviations. Such unstable activation potentials can be excluded from further analysis, particularly by blanking. Unstable activation potentials can be classified based on predicted waveforms of surface ECG and / or intracardiac electrogram 2. Alternatively, unstable activation potentials can be identified in the classification routine 15.

[0054] A noisy activation potential is one in which the noise spectrum overlaps the physiological spectrum in a relevant manner. Known methods can be used for noise estimation.

[0055] In this case, the weighted blanking preferably consists in applying different weights 28 to the electrograms 2 within each time interval 26. Preferably, the weights 28 are predefined to include a section that completely removes each time interval 26, e.g., a section that multiplies it by zero, and at least one section that reduces the amplitude of the electrograms 2. The weighted blanking can be applied in a manner different from multiplication. An example of the weights 28 can be a Gaussian curve.

[0056] The weighted blanking can be parameterized with respect to blanking weight and / or length, in particular based on the classification of the interfering signal to be blanked, thereby allowing the detection of local activation potentials 12 with a high probability of showing a clear signal even during atrial fibrillation, thereby allowing the analysis of local activation potentials during atrial fibrillation.

[0057] As an example, pacing artifacts can be completely suppressed from the onset, with blanking reduced for a defined period of time after onset, the length and / or amount of reduction may be specific to the filter settings of the hardware or software used with the control system 3.

[0058] The QRS complex may be estimated, with a dynamic penalty, from its relative contribution to the last few beats. The inventive approach allows tracking of local activation potentials 12 that gradually delay and overlap the QRS timing, often occurring at critical moments of isolation. Thus, the inventive approach allows for the determination of cardiac isolation status during the isolation procedure and during atrial fibrillation, without the need to defibrillate the patient into normal sinus rhythm.

[0059] 2 shows another example of the blanking of the time interval 29 for the CS potential 13 in this case. Here, a complete blanking of the signal in the time interval 29 can be performed by multiplication with zero.

[0060] In particular, an interference signal removal step by blanking can be performed for the discrimination step on the intracardiac electrogram 2, while the classification routine 15 may be based on an analysis of local activation potentials 12 in the intracardiac electrogram 2 without performing the various types of interference signal removal used for discrimination.

[0061] The control system 3 may furthermore also perform a quality control step in which the control system 3 removes local activation potentials 12 and / or time sections of the channel 11 of the electrogram 2 and / or the channel 11 of the electrogram 2 itself based on a quality parameter. The quality parameter may be a noise parameter, preferably a root mean square ratio, and / or may be based on power line interference detection and / or the noise parameter may be a peak to baseline ratio.

[0062] With reference to Figure 1, the multichannel electrogram 2 may include at least four, preferably at least six, more preferably at least eight channels 11. The multichannel electrogram 2 may be recorded by an ablation catheter 6. Other means include, for example, a circular catheter 6 or a multi-spline catheter 6. The multichannel electrogram 2 may be a bipolar electrogram. In a preferred alternative, the multichannel electrogram 2 is a unipolar electrogram.

[0063] According to another teaching of equal importance, a control system 3 is proposed, which is adapted to carry out the proposed method. All the explanations given with respect to the proposed method are fully applicable. The control system 3 is adapted to receive and / or measure multi-channel electrograms 2. The control system 3 is preferably connectable to an ablation catheter 6.

Claims

1. A method for determining the cardiac isolation state of a measurement position (1) in the presence of far - field interference by analyzing a multi - channel intracardiac electrogram (2) of the measurement position (1) via a control system (3), in an identification routine (9), the control system (3) applies an activation search algorithm to an analysis window (10) of at least 400 ms in at least two different channels (11) of the multi - channel intracardiac electrogram (2), and the activation search algorithm identifies a window (W) of local activation potentials (12) within the analysis window (10), in a classification routine (15), the control system (3) analyzes the local activation potentials (12) to determine the cardiac isolation state of the measurement position (1), method.

2. The multi - channel intracardiac electrogram (2) is recorded during atrial arrhythmia, particularly during atrial fibrillation or atrial flutter, and / or the measurement position (1) is at least partially located inside the atrium (16), particularly inside the left atrium (16), preferably, the measurement position (1) is an island (17) within the wall (18) of the left atrium (16) or an island (17) at the entrance of the pulmonary vein (19), and / or the measurement position (1) is at least partially located within the pulmonary vein (19), The method according to claim 1.

3. In the classification routine (15), the control system (3) analyzes the morphology of the local activation potentials (12) to determine the cardiac isolation state of the measurement position (1), preferably, in the classification routine (15), the control system (3) classifies the local activation potentials (12) into a morphology group (20), and preferably determines the cardiac isolation state based on the distribution of the local activation potentials (12) across the morphology group (20), The method according to claim 1.

4. In the classification routine (15), the control system (3) classifies the local activation potentials (12) into a morphology group (20) based on a plurality of characteristic peaks of the local activation potentials (12), Preferably, the control system (3) classifies peaks having at least a predetermined amplitude and / or peaks having at least a predetermined gradient and / or peaks having at most a predetermined gradient and / or peaks having at least a predetermined minimum peak distance and / or peaks having at most a predetermined maximum peak distance as characteristic peaks based on peak morphology, in particular based on a minimum peak angle and / or a maximum peak angle. The method according to claim 3.

5. The morphology group (20) includes a group for local activation potentials (12) having a single characteristic peak and / or exactly two characteristic peaks and / or exactly three characteristic peaks and / or four or more characteristic peaks and / or at least two characteristic peaks separated by a predetermined time. The method according to claim 4.

6. The analysis window (10) has a width of at least 400 ms, preferably at least 800 ms, more preferably at least 1.25 s, and / or The analysis window (10) has a width of at most 3 s, preferably at most 2 s, more preferably at most 1.75 s. The method according to claim 1.

7. The analysis window (10) is a sliding window that overlaps or does not overlap over the measurement time for each channel. Preferably, at least two local activation potentials (12) are extracted for each channel, and in particular at least one local activation potential (12) is extracted for each analysis window (10). More preferably, the measurement time is at least 1 s, preferably at least 2.5 s, more preferably at least 10 s. The method according to claim 1.

8. The control system (3) executes the identification routine (9) and the classification routine (15) on the multi-channel intracardiac electrogram (2) of the measurement position (1) recorded after an ablation treatment has been applied in the vicinity of, in particular around, the measurement position (1) to determine the cardiac isolation state of the measurement position (1). Preferably, additionally, the control system (3) executes at least the identification routine (9) on a multi-channel intracardiac electrogram (2) of the measurement position (1) recorded before the ablation treatment, and determines the cardiac isolation state based on a comparison of local activation potentials (12) before and after the ablation treatment. The method according to claim 1.

9. The activation search algorithm includes the local activation potential (12) and subsequently a peak detection algorithm for finding a window (W) of the local activation potential (12). Preferably, the peak detection algorithm is based on a non-linear filter, in particular a wavelet filter and / or a transformation of the multi-channel intracardiac electrogram (2), in particular a wavelet transformation, and / or includes peak detection by amplitude. The method according to claim 1.

10. In the identification routine (9), the control system (3) identifies a fixed number of local activation potentials (12) for each channel and / or for each analysis window (10), preferably for each time interval (26), in particular for each measurement window. More preferably, the fixed number is based on the physiological heart rate and / or the measured heart rate. More preferably, the fixed number is the maximum value of one local activation potential (12) for at least every 500 ms, preferably for at least every 800 ms, more preferably for at least every 1 s. The method according to claim 1.

11. Before the identification step, the control system (3) executes an interference signal removal step, which includes complete or weighted blanking of the pacing artifact and / or the CS potential (13) and / or the ECG wave (27) and the time intervals (26) around them and / or the relative time intervals (26) with respect to them. Preferably, the pacing artifact and / or the CS potential (13) and / or the ECG wave (27) are detected for an electrogram (2) different from the multi-channel intracardiac electrogram (2), and the multi-channel intracardiac electrogram (2) is a coronary sinus electrogram (2) or a surface electrogram (2). The method according to claim 1.

12. The weighted blanking is the application of various weights (28) to the multi-channel intracardiac electrogram (2) within each time interval (26), and preferably, the weights (28) are predetermined to include a section that completely removes each of the time intervals (26) and at least one section with a reduced amplitude of the multi-channel intracardiac electrogram (2). The method according to claim 1.

13. The control system (3) performs a quality management step, in which the control system (3) removes a time section of the local activation potential (12) and / or a channel (11) of the electrogram (2) based on quality parameters. Preferably, the quality parameter is a noise parameter, more preferably the root mean square ratio, and / or is based on power line interference detection and / or peak-to-baseline ratio. The method according to claim 1.

14. The multi-channel intracardiac electrogram (2) includes at least 4 channels, preferably at least 6 channels, more preferably at least 8 channels (11), and / or the multi-channel intracardiac electrogram (2) is recorded by an ablation catheter (6). The method according to claim 1.

15. A control system configured to execute the method according to any one of claims 1 to 14, wherein the control system (3) is configured to receive and / or measure a multi-channel intracardiac electrogram (2). Preferably, the control system (3) is connectable to an ablation catheter (6). Control system.

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