ECG activation pattern clustering template analysis

Abstract

To determine the source location of an arrhythmia by analyzing ECGs.SOLUTION: A method includes receiving a set of electrocardiograms (ECG) determined to belong to a given morphologic template indicative of a given type of arrhythmia. Using a location algorithm, a percentage of the ECGs in the set is calculated, which points to a same source location of the given type of arrhythmia. The calculated percentage is compared to a predefined threshold percentage. If the percentage of ECGs is found to exceed the threshold percentage, the source location is reported to a user.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to the analysis of electrocardiograms (ECGs), and more particularly to determining the source location of arrhythmias by analyzing ECGs. [Background technology]

[0002] Some types of ventricular arrhythmias, such as premature ventricular contractions (PVCs), can be diagnosed using an ECG. For example, a 12-lead ECG is useful for providing initial evidence of PVC frequency and is a high-quality noninvasive tool for determining PVC source location and preferred access areas. If PVCs are suspected based on either the patient's history or physical examination, it is useful to continue performing a long ECG acquisition (e.g., up to 1 minute) to more precisely determine PVC frequency and capture PVCs during recording of all 12 simultaneous leads to enable the most accurate morphological assessment.

[0003] A method for identifying PVCs by identifying at least one ECG as belonging to a given morphological template is provided in U.S. Patent No. 11,730,414, which describes, in one embodiment, a medical system including respective electrodes for application to a subject's body and a processor. The electrodes are configured to output respective sets of activation signals in response to electrical activity of the subject's heart captured over a series of cardiac intervals. The processor is configured to classify a first cardiac interval of the set of activation signals as a first morphological template, calculate a similarity measure between a second cardiac interval of the set of activation signals and the first morphological template in response to the measure exceeding a predetermined threshold, group the second cardiac interval of the set of activation signals within the first morphological group with the first morphological template in response to the measure not exceeding the predetermined threshold, classify the second cardiac interval of the set of activation signals as a second morphological template in response to the measure not exceeding the predetermined threshold, and repeat the above, mutatis mutandis, for subsequent cardiac intervals.

[0004] Several academic publications provide location algorithms for estimating the origin of arrhythmias based on non-invasive ECG data, such as 12-lead ECGs or Holter monitors. For example, in a paper titled "Park Algorithm as Predictor of Disease Origin in Three-Dimensional Mapping Electrophysiological Studies" published in the International Journal of General Medicine, Vol. 13, pp. 1083-1092 (2020), Muzakkir Amir et al. describe the validation of the accuracy of the Park algorithm in predicting the origin of PVCs using 12-lead ECGs in both cases of PVCs with and / or without structural heart disease. The researchers found that the Park algorithm is suitable for use in determining the origin of PVCs in the right or left heart.

[0005] Park et al. described their location algorithm in a paper titled "Using the surface electrocardiogram to localize the origin of idiopathic ventricular tachycardia" published in the journal Pacing Clinical Electrophysiology Vol. 35, Iss. 12, pp. 1516-1527 (2012).

[0006] The present disclosure will be more fully understood from the following detailed description of the embodiments thereof, taken in conjunction with the drawings in which: [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic, depiction of a cardiac system configured for cardiac electrophysiological (EP) sensing, EP signal analysis, and ablation, in accordance with an embodiment of the present disclosure. FIG. [Figure 2]FIG. 1 is a schematic diagram of a morphological template used to analyze a 12-lead ECG acquisition showing a given type of arrhythmia, according to an example of the present disclosure. [Figure 3] 1 is a flowchart that schematically illustrates a method for statistically determining cardiac origin locations of arrhythmias using morphological templates, according to an example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] overview Premature ventricular contractions (PVCs) are extra beats that begin in one of the heart's ventricles. These extra beats disrupt the normal heart rhythm, sometimes causing flutter or the sensation of a skipped beat.

[0009] PVCs causing ectopic beats can occur singly or in a repetitive pattern. The occurrence of three or more consecutive PVCs is classified as ventricular tachycardia (VT). One cause of ectopic beats is reentrant signaling, in which the heartbeat is initiated by the Purkinje fibers rather than the SA node. For example, if one Purkinje fiber pathway is blocked and another pathway experiences slower conduction, it can induce ectopic beats along the post-block pathway. Therefore, in some cases, PVCs are treated using ablation of the ventricular tissue location causing the ectopic beat (e.g., the location of the associated papillary muscles).

[0010] Accurate estimation of the ventricular source location of arrhythmias using noninvasive ECG can be used to select optimal protocols for invasive treatments such as catheter ablation. To this end, various location algorithms, such as those described in the Background section, have been developed to predict the source location of arrhythmias using noninvasive ECG techniques (e.g., 12-lead, Holter).

[0011] However, given the importance of the decisions required (e.g., which invasive procedure to perform based on the estimated location), maximizing the level of confidence in the source location determination has significant advantages.

[0012] Examples of the present disclosure described below provide techniques for determining with high confidence the location of arrhythmia sources, such as PVCs, by analyzing non-invasively acquired ECGs (e.g., 12-lead acquired ECGs, Holter acquired ECGs). In examples, the disclosed algorithms enable a processor to identify the most repetitive and representative 12-lead ECG templates of heartbeats for PVCs. Using statistical analysis on one or more patterns (i.e., morphological templates) enables the processor to verify the correct tissue source location within the heart to a high level of confidence.

[0013] In one example, a processor receives a set of electrocardiograms (ECGs) determined to belong to a given morphological template ("cluster of ECGs") indicative of a given type of arrhythmia, e.g., a set of ECGs obtained using the method described in the aforementioned U.S. Patent No. 11,730,414. A user can determine a threshold (percentage match) for inclusion in such clustering. Using a location algorithm, such as the Perkins algorithm (for PVCs) described above, the processor calculates the percentage of ECGs in the given set that point to the same source location of the given type of arrhythmia. The processor then compares the calculated percentage with a predetermined threshold percentage. If the calculated percentage of ECGs is found to exceed the threshold percentage, the processor reports the source to the user.

[0014] The number of ECGs in the set can reach 100 or more, and a high level of statistical certainty can be achieved with this method because a sufficient number of them point to the same source location. For example, if a sufficient percentage of a sufficient number of ECGs (e.g., several tens of ECGs) point to the same location (source) of the PVC, this effectively verifies the exact PVC source.

[0015] System Description 1 is a schematic, depiction of a system 20 configured for cardiac electrophysiological (EP) sensing, EP signal analysis, and ablation, according to an example of the present disclosure. System 20 includes a standalone ECG recorder 35. Recorder 35 is typically used by a physician to view an analog ECG signal, such as a 12-lead ECG trace (also shown as trace 44 on display device 27).

[0016] System 20 includes a processing interface unit (PIU) 24, such as those used by the CARTO™ system produced by Biosense-Webster. ECG leads connected to PIU 24 are sampled for further processing and directed to a recorder 35 for real-time display of the raw ECG signals. For clarity, elements such as power cables, sockets, and inlets have been omitted from FIG. 1.

[0017] As can be seen, system 20 includes a catheter 21 having a shaft 22 that is navigated into a heart 26 of a patient 28 by a physician 30. In the depicted example, physician 30 inserts shaft 22 through a sheath 23 while manipulating shaft 22 using a manipulator 32 near the proximal end of the catheter.

[0018] The distal end 40 (shown in inset 25) of catheter 21 is fitted with electrodes that can be used for pacing, EP mapping, or ablation. The proximal end of catheter 21 is connected to PIU 24 and, e.g., via PIU 24, to recorder 35, e.g., via output 55 connection of PIU 24.

[0019] The PIU 24 receives ECG waveforms (e.g., traces) 44 from body-surface ECG patches 49. Typically, the patches 49 are attached to the skin around the chest and legs of the patient 28. The PIU 24 is connected to the patches 49 by wires that run through the cable 39 and receives signals from the ECG patches 49. The ECG traces 44 are shown on the display device 27 (typically delayed relative to the same ECG traces shown on the recorder 35). Additionally, the recorder 35 may receive intracardiac signals acquired by electrodes on the catheter 21.

[0020] PIU 24 may include processor 41, which may be, for example, a general-purpose computer with suitable front-end and interface circuitry 38 for receiving various signals. In one example of the disclosed technology, processor 41 applies an algorithm that (a) clusters ECG traces 44 and (b) analyzes the clustered ECGs acquired over a given number of heartbeats to indicate the location (origin) of ventricular arrhythmias, such as PVCs.

[0021] In another example, processor 41 uses information contained in intracardiac ECG signals acquired using catheter 21 to construct electrophysiological map 31 and present it on display device 27.

[0022] During an EP mapping procedure, the locations of the catheters can be tracked while they are within the patient's heart 26. Such tracking can be performed using the Active Current Location (ACL) system from Biosense-Webster, Inc., described in U.S. Pat. No. 8,456,182, the disclosure of which is incorporated herein by reference.

[0023] Thus, processor 41 can associate a given signal received from the catheter, such as an intracardiac ECG, with the location where the signal was obtained. Processor 41 uses the information contained in these signals to construct an EP map, such as a local activation time (LAT) map, for showing on a display. To perform ablation, the electrodes of the catheter can be connected (e.g., switched) to generator 47.

[0024] The processor 41 is typically programmed with software to perform the functions described herein. The software may be downloaded to the processor in electronic form, for example over a network, or the software may alternatively or additionally be provided and / or stored on non-transitory tangible media such as magnetic, optical, or electronic memory.

[0025] ECG activation patterns clustered into morphological templates FIG. 2 is a schematic diagram of a morphological template 202 used to analyze a 12-lead ECG acquisition indicative of a given type of arrhythmia, according to an example of the present disclosure. FIG. 2 shows an ECG 204 acquired using a 12-lead ECG recorder. The morphological template 202 can be used in conjunction with the method of U.S. Pat. No. 11,730,414, discussed above, to obtain a set of ECGs suitable for the statistical analysis methods disclosed herein. For example, assuming a heart rate of 60 BPM, 60 ECG patterns are acquired, one portion of which represents normal sinus rhythm and may be clustered using a normal sinus rhythm template (not shown), and another portion is classified into categories defined by the morphological template 202.

[0026] In a first step, using the disclosed technique of applying a location algorithm to ECGs that fit the morphological template 202, a clinician can statistically assess the confidence level that a given source location is responsible for the occurrence of an abnormal ECG. Based on the confidence level, the type of invasive clinical approach can be determined according to the clinician's discretion.

[0027] Statistical determination of cardiac source location of arrhythmias using morphological templates. 3 is a flow chart that schematically illustrates a method for statistically determining cardiac origin locations of arrhythmias using morphological templates, according to an example of the present disclosure. The process executes an algorithm that begins in a data reception step 302, where the processor 41 receives a set of ECGs that have been determined to belong to a given morphological template 202 indicative of a given type of arrhythmia.

[0028] Next, in a calculation step 304, using a location algorithm, processor 41 calculates the percentage of ECGs in a given set that point to the same source location of a given type of arrhythmia. For example, the processor calculates the percentage of ECGs that point to the ventricular tissue source location of a PVC.

[0029] In a percentage comparison step 306, the processor compares the calculated percentage to a predetermined threshold percentage.

[0030] The processor checks the results of the comparison in step 308. If the ECG percentage is found to exceed the threshold percentage, the processor reports the source location to the user in a reporting step 310. The report may be a note on the display device 27 and / or a highlighted area in the 3D anatomical model shown on the display device.

[0031] The flowchart in Figure 3 is provided as an example and has been simplified for clarity of presentation. In another example, the disclosed method is applied one by one to ECG sets collected under different morphological templates. [Example]

[0032] Example 1 The method includes receiving 202 a set of electrocardiograms (ECGs) determined to belong to a given morphological template indicative of a given type of arrhythmia. Using a location algorithm, the percentage of ECGs in the set that point to the same source location of the given type of arrhythmia is calculated. The calculated percentage is compared to a predetermined threshold percentage. If the percentage of ECGs is found to exceed the threshold percentage, the source location is reported to a user 30.

[0033] Example 2 The method according to example 1, wherein the morphological template (202) is indicative of a premature ventricular contraction (PVC) type arrhythmia.

[0034] Example 3 The method according to any of Examples 1 and 2, wherein reporting the source location includes reporting an anatomical region within the heart (26).

[0035] Example 4 The method according to any of Examples 1 to 3, wherein the set of ECGs was acquired using a 12-lead ECG recorder (35).

[0036] Example 5 The system 20 includes an interface 24 and a processor 41. The interface 24 is configured to receive a set of electrocardiograms (ECGs) determined to belong to a given morphological template 202 indicative of a given type of arrhythmia. The processor 41 is configured to (i) use a location algorithm to calculate the percentage of ECGs in the set that point to the same source location of the given type of arrhythmia, (ii) compare the calculated percentage with a predetermined threshold percentage, and (iii) report the source location to a user 30 if the percentage of ECGs is found to exceed the threshold percentage.

[0037] Although the embodiments described herein primarily address cardiac diagnostic applications, the methods and systems described herein may also be used in other medical applications.

[0038] It will be understood that the above-described embodiments are given by way of example, and that the present disclosure is not limited to what is particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon reading the foregoing description.

[0039] [Embodiment] (1) receiving a set of electrocardiograms (ECGs) determined to belong to a given morphological template indicative of a given type of arrhythmia; calculating the percentage of the ECGs in the set that point to the same source location of the given type of arrhythmia using a location algorithm; comparing the calculated percentage to a predetermined threshold percentage; and reporting the source location to a user if the percentage of the ECG is found to exceed the threshold percentage. (2) The method described in embodiment 1, wherein the morphological template indicates a premature ventricular contraction (PVC) type arrhythmia. (3) The method of embodiment 1, wherein reporting the source location includes reporting an anatomical region within the heart. (4) The method of embodiment 1, wherein the set of ECGs was acquired using a 12-lead ECG recorder. (5) an interface configured to receive a set of electrocardiograms (ECGs) determined to belong to a given morphological template indicative of a given type of arrhythmia; 1. A processor, comprising: using a location algorithm to calculate the percentage of the ECGs in the set that point to the same source location of the given type of arrhythmia; comparing the calculated percentage to a predetermined threshold percentage; a processor configured to report the source location to a user if the percentage of the ECG is found to exceed the threshold percentage.

[0040] (6) The system described in embodiment 5, wherein the morphological template indicates a premature ventricular contraction (PVC) type arrhythmia. (7) The system of embodiment 5, wherein the processor is configured to report the source location by reporting an anatomical region within the heart. (8) The system of embodiment 5, wherein the set of ECGs is acquired using a 12-lead ECG recorder.

Claims

1. an interface configured to receive a set of electrocardiograms (ECGs) determined to belong to a given morphological template indicative of a given type of arrhythmia; 1. A processor, comprising: using a location algorithm to calculate the percentage of the ECGs in the set that point to the same source location of the given type of arrhythmia; comparing the calculated percentage to a predetermined threshold percentage; a processor configured to report the source location to a user if the percentage of the ECG is found to exceed the threshold percentage.

2. The system of claim 1 , wherein the morphological template is indicative of a premature ventricular contraction (PVC) type arrhythmia.

3. The system of claim 1 , wherein the processor is configured to report the source location by reporting an anatomical region within the heart.

4. The system of claim 1 , wherein the set of ECGs was acquired using a 12-lead ECG recorder.

5. receiving a set of electrocardiograms (ECGs) determined to belong to a given morphological template indicative of a given type of arrhythmia; using a location algorithm to calculate the percentage of the ECGs in the set that point to the same source location of the given type of arrhythmia; comparing the calculated percentage to a predetermined threshold percentage; and reporting the source location to a user if the percentage of the ECG is found to exceed the threshold percentage.

6. The method of claim 5 , wherein the morphological template is indicative of a premature ventricular contraction (PVC) type arrhythmia.

7. The method of claim 5 , wherein reporting the source location includes reporting an anatomical region within the heart.

8. The method of claim 5 , wherein the set of ECGs was acquired using a 12-lead ECG recorder.

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