JP-7855823-B2 - Annotation of slow electrophysiological (EP) cardiac pathways associated with ventricular tachycardia (VT)

JP7855823B2JP 7855823 B2JP7855823 B2JP 7855823B2JP-7855823-B2

Inventors

タル・ハイム・バル－オン
メイル・バル－タル
ガル・ハヤム
エイナット・シャピラ

Assignees

バイオセンス・ウエブスター・（イスラエル）・リミテッド

Dates

Publication Date: 20260511
Application Date: 20220418
Priority Date: 20210419

Claims (20)

A system for evaluating electrical propagation within the heart, It is an interface, A pacing signal applied to a patient's heart, wherein the pacing signal includes (i) a sequence of normal pacing stimuli at sinus rhythm intervals, and (ii) one or more abnormal pacing stimuli at abnormal intervals shorter than the sinus rhythm intervals. An interface configured to receive cardiac signals sensed by electrodes located within the heart and electrodes on the patient's body surface in response to the pacing signal, It is a processor, Finding and annotating model responses from evoked potentials caused by the aforementioned normal pacing stimulus, Correlating the model responses along different signal sections to find annotations for a first evoked potential caused by the normal pacing stimulus, and annotations for a second evoked potential caused by one or more abnormal pacing stimuli, according to the index in the signal section that received the highest scoring in the model response, Calculate the first time delay and the second time delay, Calculating the time difference between normal time delay and reduced time delay, A system comprising a processor configured to present to a user an EP map of at least a portion of the heart, which includes a graphical representation of the time difference presented at a location within the heart .
The system according to claim 1, wherein the processor is configured to correlate the model responses by weighting the correlation between the model responses according to the derivatives of the one or more signals.
The system according to claim 1, wherein the processor is configured to estimate the first time delay and the second time delay by annotating the estimated bipolar signals of the first time delay and the second time delay .
The system according to claim 1, wherein the interface is further configured to receive electrocardiogram (ECG) signals from external electrodes of the patient, and the processor is configured to use the ECG signals to estimate whether a stable contraction occurred in response to a predefined number of normal pacing stimuli and one or more abnormal pacing stimuli , and to discard portions of the cardiac signals in which each ECG does not indicate a stable contraction.
The system according to claim 4, wherein the processor is configured to estimate the stable contraction by estimating the repeatability of evoked potentials in the cardiac signal .
The system according to claim 4, wherein the processor is configured to estimate the stable contraction by smoothing the cardiac signal and detecting the evoked potentials in the smoothed cardiac signal .
The system according to claim 4, wherein the processor is configured to estimate one or more correlations by identifying the far-field from the near-field signal.
The system according to claim 1, wherein the processor is configured to present the EP map by adjusting the scale of the GUI to define the minimum positive value of the time difference displayed on the EP map.
The system according to claim 1, wherein the processor is configured to present the EP map by overlaying an artificial icon, graphically coded to represent the time difference value, onto the EP map.
The system according to claim 1, wherein the processor is configured to present the EP map by indicating the occurrence of abnormal ventricular activity to the user.
The system according to claim 10, wherein the processor is configured to indicate the occurrence of the abnormal ventricular activity by using at least one of color and surface morphology on the EP map.
The system according to claim 1, wherein the interface is configured to receive the cardiac signal by receiving unipolar and bipolar electrophoresis obtained using a catheter.
The system according to claim 1, wherein the processor is configured to estimate the highest scoring correlation by training a machine learning model to estimate the highest scoring correlation based on a pre-specified metric.
A method for operating a system for evaluating electrical propagation within the heart, The aforementioned system comprises an interface and a processor, The interface receives a pacing signal applied to the patient's heart, wherein the pacing signal includes (i) a sequence of normal pacing stimuli at sinus rhythm intervals, and (ii) one or more abnormal pacing stimuli at abnormal intervals shorter than the sinus rhythm intervals. The interface receives cardiac signals in response to the pacing signal, which are sensed by electrodes located within the heart and electrodes on the patient's body surface. The processor finds and annotates a model response from the evoked potentials caused by the normal pacing stimulus, The processor correlates the model responses along different signal sections to find annotations for first evoked potentials caused by the normal pacing stimulus and annotations for second evoked potentials caused by one or more abnormal pacing stimuli, according to the index in the signal section that received the highest scoring in the model response. The processor calculates the first time delay and the second time delay, The aforementioned processor calculates the time difference between the normal time delay and the reduced time delay, A method of operating the system , comprising the processor presenting to the user an EP map of at least a portion of the heart, which includes a graphical representation of the time difference presented at a location within the heart .
A method of operating the system according to claim 14, wherein the process of the processor correlating the model responses includes the processor weighting the correlations between the model responses according to the derivatives of one or more signals.
A method of operating the system according to claim 14, wherein the processor estimating the first time delay and the second time delay includes the processor annotating the estimated bipolar signals of the first time delay and the second time delay .
A method of operating the system according to claim 14, comprising: the interface receiving respective electrocardiogram (ECG) signals from external electrodes of the patient; the processor using the ECG signals to estimate whether a stable contraction occurred in response to a predefined number of normal pacing stimuli and one or more abnormal pacing stimuli ; and the processor discarding portions of the cardiac signals in which each ECG does not indicate a stable contraction.
A method of operating the system according to claim 17, wherein the processor estimating the stable contraction includes the processor estimating the repeatability of evoked potentials in the cardiac signal .
A method of operating the system according to claim 17, wherein the processor estimates the stable contraction by smoothing the cardiac signal and the processor detects the evoked potential in the smoothed cardiac signal .
A method of operating the system according to claim 17, wherein the processor estimating one or more correlations includes the processor identifying a far-field signal from a near-field signal.

Description

This invention generally relates to electrophysiological (EP) signals, and more specifically, to a method for evaluating electrical propagation within the heart. Annotation of electrophysiological signals for determining local activation time (LAT) has been previously proposed in the patent literature. For example, U.S. Patent No. 9,662,178 describes various embodiments of a system and method for identifying arrhythmogenic circuits in a patient. In one embodiment, the method includes: acquiring electrographic data recorded at various locations in the heart while performing programmed ventricular pacing with additional stimulation; using the recorded electrographic data to acquire decrease values at at least two different locations in the heart; using the decrease values to generate at least a portion of a decrease map; and identifying arrhythmogenic circuits based on electrographic data having significant decrease characteristics. As another example, U.S. Patent Application Publication 2018/0089825 describes a method for identifying isthmuses in a three-dimensional map of cardiac chambers by a processing unit configured to perform: a) a correlation step between sets of stimulation points in cardiac chambers, where each stimulation point is represented by a set of signals obtained after surface electrocardiography (ECG), excluding ventricular tachycardia; b) a watershed line identification step based on the above correlation results and the 3D coordinates of the stimulation points in a 3D map; and c) an isthmus determination step based on 3D corridors substantially traversing the watershed lines. International Publication No. 2018/073722 describes a computer implementation method and computer program product for identifying ventricular arrhythmogenic substrates in myocardial scars or fibrous tissue. Multiple mapping points acquired from a patient are stored in a signal acquisition unit, and the mapping points include ECG signals, electrogeographic (EGM) signals, and the 3D location of the EGM signals. The method includes, for a reference mapping point, a) detecting each pulse present in one recorded ECG signal and identifying a target pulse from the detected pulses; b) identifying the major EGM wave associated with the identified target pulse; c) identifying the start and end time landmarks of the major EGM wave providing a primary drawn EGM signal and measuring the voltage amplitude of the primary drawn EGM signal; d) performing further analysis of the primary drawn EGM; and e) creating a cardiac conduction channel map and propagation map based on the results of tagging performed during the analysis. A more complete understanding of the disclosure can be obtained by reading the following detailed description of embodiments in conjunction with the drawings. This is a schematic diagram of a catheter-based electrophysiological (EP) mapping system according to an exemplary embodiment of the present invention. An exemplary graph of a bipolar potential diagram obtained using the system of Figure 1, which has decrement-evoked potentials (DeEPs) annotated on the bipolar signal, is shown according to an exemplary embodiment of the present invention. This is a schematic descriptive volume rendering of a ventricular EP map showing the tissue location and size of DeEPs that can cause ventricular tachycar (VT), according to an exemplary embodiment of the present invention. This flowchart schematically illustrates a method and algorithm for DeEP annotation in a bipolar potential diagram according to an exemplary embodiment of the present invention. Overview Cardiac tachycardias, such as ventricular tachycardia (VT) or atrial tachycardia, are cardiac rhythm disorders (arrhythmias) caused by abnormal electrical signals within the cardiac chambers. For example, VT can be caused by abnormal electrical signals within the lower chamber of the heart (ventricles). VT can be caused by local electrophysiological (EP) conduction defects in ventricular tissue, such as scar tissue. To locate and treat the site of such arrhythmias, the ventricles may be paced and EP-mapped using a catheter to identify the abnormal tissue location (e.g., a location showing delayed evoked potentials) that may be causing the VT, for example by ablation. Specifically, EP mapping can be performed in support of a therapeutic approach called "scar homogenization," which has proven useful for ablating scar tissue across the entire area of the scar. The motivation behind ablationary therapy is to target poorly connected ventricular tissue fibers that survive within the resulting scar. These bundles are thought to generate EP pathways exhibiting slow conduction (scar isthmus), which is considered to be the cause of VT. To achieve this goal, EP mapping of scar tissue, followed by scar homogenization, appears to be the optimal endpoint of the procedure for eliminating VT so far. To perform EP mapping of pathways and circuits leading to tachycardia, tachycardia is