Annotation of delayed potentials including focal abnormal ventricular excitation (LAVA) signals

Abstract

To provide a method for evaluation of electrical propagation in the heart.SOLUTION: A method includes receiving a signal sensed by a pair of bipolar electrodes 22 at a location in the heart of a patient. One or more electrocardiogram (ECG) signals are received, and sensed by external electrodes 24 attached to the patient. Two or more successive QRS complexes are identified in the bipolar signal. One or more activations are detected in the bipolar signal, which occur within a window of interest that begins at least a given time with respect to the identified QRS complexes. It is checked whether the detected activations are late potentials, by verifying whether (i) the activations do not coincide with an event observed in the ECG signals, and (ii) the activations are repeatable in the successive QRS complexes. In response to determining that at least one of the detected activations is a late potential, the latest of the late potentials is visualized to a user.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention generally relates to electrophysiological (EP) signals, and more specifically, to a method for evaluating electrical propagation within the heart.

Background Art

[0002] Annotation of electrophysiological signals for determining local activation time (LAT) has been previously suggested in the patent literature. For example, U.S. Patent Application Publication 2016 / 0128785 describes various embodiments of a system and method for identifying arrhythmic circuits in a patient or subject. In one embodiment, the method includes: acquiring electrographic data recorded at various locations of the heart while performing ventricular pacing programmed with additional stimulation to induce ventricular tachycardia (VT); using the recorded electrographic data to acquire decrease values ​​at at least two different locations of the heart; using the decrease values ​​to generate at least a portion of a decrease map; and identifying arrhythmic circuits based on electrographic data having significant decrease characteristics. Late potentials, which are local potentials (excitations) that generally occur after the end of QRS complex, are reproducibly observed at timings reproducible from repetitive pacing or sinus rhythm. Abnormal potentials are frequently observed within the QRS complex (these have given rise to the terms "left ventricular abnormal local excitation" or local abnormal ventricular activity (LAVA)). The problem here is the obvious subjectivity of the operator and the risk that these signals are nonspecific targets, which poses the risk of excessive ablation in areas that do not possess the properties to induce or maintain reentrant VT. Therefore, regions of late potentials during sinus rhythm (SR), as well as pacing on both the endocardial and epicardial surfaces, were also characterized in the study. Color-coded substrate maps were created by applying scar mapping and late potentials (LP) mapping during SR and ventricular pacing. Regions of LP were defined as any local activity after the end of the surface QRS complex. Very late potentials (VLP) were defined as local activity beyond 50 ms from the end of the surface ECG QRS complex.

[0003] As another example, U.S. Patent Application Publication 2017 / 0156612 describes how cardiac activity (e.g., electrocardiogram) is analyzed for focal abnormal ventricular activity (LAVA), including by using a LAVA detection and analysis module incorporated into an electroanatomical mapping system. The module converts the electrocardiogram signal to a wavelet region for calculation as a scalogram, calculates a one-dimensional LAVA function of the scalogram, detects one or more peaks in the LAVA function, and calculates the inter-peak amplitude of the electrocardiogram signal. If the inter-peak amplitude does not exceed a preset amplitude threshold, the module can then calculate one or more LAVA delay parameters of the electrocardiogram signal using one of the one or more peaks detected in the LAVA function and the LAVA probability parameter of the electrocardiogram signal. [Overview of the Initiative] [Means for solving the problem]

[0004] Embodiments of the present invention described below provide a method for receiving bipolar signals sensed by a pair of electrodes at a location within a patient's heart. One or more electrocardiogram (ECG) signals are sensed and received by one or more body surface electrodes attached to the patient. Two or more consecutive QRS sequences are identified in the bipolar signal. One or more excitations are detected in the bipolar signal, occurring within a window of interest that begins at least a given time for the identified QRS sequence. Whether one or more detected excitations are delayed potentials is determined by verifying (i) whether one or more excitations do not coincide with a predetermined event observed in one or more ECG signals, and (ii) whether one or more excitations are repeatable in a consecutive QRS sequence. In response to determining that at least one of the detected excitations is a delayed potential, the most recent of at least one of the delayed potentials is visualized to the user.

[0005] In some embodiments, visualizing the latest delayed potential includes graphically displaying the latest delayed potential on an electrophysiological (EP) map in relation to the positions of a pair of electrodes within the heart. In other embodiments, visualizing the latest delayed potential includes annotating the latest delayed potential.

[0006] In one embodiment, the default event includes excitation observed in one or more ECG signals. In another embodiment, the default event includes fractionation observed in one or more ECG signals.

[0007] In some embodiments, verifying whether one or more excitations are repeatable includes verifying whether one or more excitations recur in at least a given number of cardiac cycles. In other embodiments, verifying whether one or more excitations recur includes using pattern matching.

[0008] In the embodiment, the latest delayed potential includes a localized abnormal ventricular activity (LAVA) signal.

[0009] In some embodiments, detecting excitation includes applying filtration to smooth the bipolar signal and detecting one or more excitations in the smoothed bipolar signal that have an amplitude above a given threshold.

[0010] In some embodiments, the received bipolar signal includes a ventricular bipolar signal acquired by a catheter electrode.

[0011] In embodiments, the method further includes receiving a unipolar signal at a location and identifying two or more consecutive QRS complexes in the unipolar signal. One or more excitations are detected in the unipolar signal occurring within a window of interest that begins at least a given time with respect to the identified QRS complex. It is confirmed whether the detected one or more excitations are delayed potentials by verifying (i) whether the one or more excitations do not coincide with a predetermined event observed in one or more ECG signals, and (ii) whether the one or more excitations are repeatable in a consecutive QRS complex. In response to determining that at least one of the detected one or more excitations is a delayed potential, the most recent of at least one of the one or more delayed potentials is visualized to the user.

[0012] In some embodiments, determining whether one or more detected excitations are delayed potentials is performed in real time.

[0013] In some embodiments, the method further includes modifying parameters used to identify, detect, verify, determine, and visualize signals.

[0014] In another embodiment of the present invention, an apparatus including an interface and a processor is additionally provided. The interface is configured to receive bipolar signals sensed by a pair of electrodes at a location within the patient's heart and to receive one or more electrocardiogram (ECG) signals sensed by one or more body surface electrodes attached to the patient. The processor is configured to (i) identify two or more consecutive QRS groups in the bipolar signals, (ii) detect one or more excitations in the unipolar signals that occur within a window of interest starting at least a given time for the identified QRS groups, (iii) verify whether the detected one or more excitations are delayed potentials by (a) whether one or more excitations do not coincide with a predetermined event observed in one or more ECG signals, and (b) whether one or more excitations are repeatable in consecutive QRS groups, and (iv) in response to determining that at least one of the detected one or more excitations is a delayed potential, visualize to the user the most recent of at least one of the one or more delayed potentials. [Brief explanation of the drawing]

[0015] A more complete understanding of the disclosure can be obtained by reading the following detailed description of embodiments in conjunction with the drawings. [Figure 1] This is a schematic diagram of a catheter-based electrophysiological (EP) mapping system according to an exemplary embodiment of the present invention. [Figure 2] This is a graph of a surface electrocardiogram (ECG) and a bipolar intracardiac potential recorded using the system shown in Figure 1, which has ventricular excitation annotated on a bipolar signal according to an embodiment of the present invention. [Figure 3] This is a graph of bipolar electrocardiogram and electrocardiogram (ECG) signals analyzed to identify and annotate localized abnormal ventricular activity (LAVA) according to an embodiment of the present invention. [Figure 4]This flowchart schematically illustrates a method and algorithm for detecting abnormal (aberrant) ventricular activity in a bipolar electrophoresis, according to an exemplary embodiment of the present invention. [Figure 5A] This is a schematic volume rendering of an electrophysiological (EP) map of the ventricle, showing completely normal tissue and partially abnormal tissue, according to an exemplary embodiment of the present invention. [Figure 5B] This is a schematic volume rendering of an electrophysiological (EP) map of the ventricle, showing completely normal tissue and partially abnormal tissue, according to an exemplary embodiment of the present invention. [Modes for carrying out the invention]

[0016] Overview Ventricular tachycardia (VT) is a cardiac rhythm disorder (arrhythmia) caused by abnormal electrical signals in the lower ventricles (ventricles) of the heart. 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, for example by ablation, the ventricles may be paced and EP-mapped using a catheter to identify the abnormal tissue location that may be causing the VT.

[0017] Specifically, EP mapping is performed in support of a therapeutic approach called "scar homogenization," which has been found to be useful for ablating scar tissue across the entire area of ​​the scar. The motivation behind ablation therapy is to target poorly connected ventricular tissue fibers that survive within the resulting scar. These bundles are thought to generate focal abnormal ventricular activity (LAVA) and are considered to be the cause of VT. To achieve this goal, EP mapping of scar tissue, followed by scar homogenization, appears to be the endpoint of the optimal procedure for eliminating all identified LAVA.

[0018] However, some patients with VT cannot tolerate the extended catheter EP mapping procedure, which limits the ability to EP map the ventricles and then treat VT. As a complex matter, the efficient identification of the location of conduction defects within ventricular tissue is particularly difficult for at least two reasons. · Strong ventricular EP activity (appearing in the EP signal by the QRS complex) can mask small abnormal EP signals from specific local ventricular sites. · There can be more than one abnormal excitation present in bipolar intracardiac signals associated with the major (QRS) excitation, only some of which are clinically important.

[0019] For such reasons, abnormal excitations that should be annotated for generating an EP map of the arrhythmogenic ventricular location can be lost by the user.

[0020] Embodiments of the present invention described below provide a method and system for annotating delayed potentials in bipolar or unipolar ventricular signals that can automatically analyze recorded ventricular signals including recorded bipolar and unipolar ventricular signals and identify LAVA for presentation on an EP map of the ventricles.

[0021] These delayed potentials, which are preferably seen against a somewhat quiet background of EP activity, can be analyzed more consistently and efficiently by the disclosed method.

[0022] The disclosed automatic analysis uses two algorithms that are applied after the major excitation points (of the QRS complex) are annotated. The algorithms are related, one being a general delayed potential (LP) detection algorithm and the other being a general LP algorithm adjusted to more robustly detect LAVA, for example, by considering the subdivided QRS complex in the analysis. For example, the LAVA algorithm excludes bipolar excitations that are considered to coincide with the fractionation seen on the ECG signal.

[0023] The LP and LAVA algorithms scan the electrogram waveform from a late time (i.e., the right of the graph) to an early time (i.e., the left of the graph) after the major annotation until the scan points coincide with the major annotation points. The algorithms search from right to left within a window of interest (WOI) set by the physician to search for delayed excitation candidates. The LP and LAVA algorithms select the latest bipolar excitation candidates, which can be determined to be consistent with the previous beat and / or the second previous beat (i.e., having a measure of temporal stability), and of the same activity type (thus overcoming mechanically induced ventricular contractions of the catheter), and satisfy certain criteria such as excitation, and select the latest excitation in the WOI that is consistent with (e.g., also occurring there) the compared beats.

[0024] In an embodiment, the processor analyzes temporally consecutive bipolar and unipolar signals, and if a bipolar excitation with a delay is determined as a candidate and the processor repeats itself along a predefined cardiac cycle, the processor indicates such a signal, for example, by annotating the excitation, likely as the occurrence of abnormal local ventricular activity. If the processor determines that one or more of the detected excitations are delayed potentials, the processor visualizes only the latest of at least one of the detected potentials (e.g., on an EP map) to the user as the LP potential.

[0025] Additionally, stability can also be measured by comparing the ECG signal morphology of the current beat (measured from the body surface patch) with the previous beat. In other words, the beats provided by the ECG signal should be consistent (and by implication having the same chamber excitation sequence) for determining delayed abnormal excitations from bipolar and monopolar intracardiac signals.

[0026] Optionally, to improve efficiency, the WOI is narrowed (by the physician) to include the area immediately to the right of the primary annotated excitation from the right-side boundary of the WOI. This focuses the algorithm on a specific ventricular tissue region, assuming that the local signal moves over time depending on where the mapping catheter is positioned within the ventricle.

[0027] The disclosed algorithm filters a bipolar signal using amplitude measurements within a specific voltage window (also known as V-WOI) of interest. This amplitude measurement window defines the amplitude of the local signal in mV, which is a very limited amplitude compared to the reduced QRS amplitude. The reduced amplitude window is found by searching for a "quiet" region of the signal (limiting how far one goes when searching for the "quiet" region) by exploring either side of the annotation. In this way, the disclosed bipolar signal analysis algorithm eliminates the major excitation (i.e., QRS) from consideration.

[0028] Typically, a processor is programmed with software that includes specific algorithms that enable it to perform each of the processor-related processes and functions outlined above.

[0029] The disclosed method for detecting abnormal ventricular activity may improve the safety and value of diagnostic catheterization by enabling physicians to perform automated analysis of diagnostic value.

[0030] System Description Figure 1 is a schematic diagram of a catheter-based electrophysiological (EP) mapping system 21 according to an exemplary embodiment of the present invention. Figure 1 illustrates a physician 27 using an electroanatomical mapping catheter 29 to perform electroanatomical mapping of the heart 23 of a patient 25. The mapping catheter 29 includes one or more arms 20 at its distal end, each of which is connected to a bipolar electrode 22 including adjacent electrodes 22a and 22b.

[0031] During the mapping procedure, the position of the electrodes 22 is tracked while they are located within the patient's heart 23. For this purpose, an electrical signal is transmitted between the electrodes 22 and the external electrodes 24. For example, three external electrodes 24 may be connected to the patient's chest, or another three external electrodes may be connected to the patient's back. (Only one external electrode is shown in Figure 1 for illustrative purposes.)

[0032] Based on the signals and considering the known locations of the electrodes 24 on the patient's body, the processor 28 calculates the estimated location of each electrode 22 within the patient's heart. Each EP data, such as a bipolar electrophysiological trace, is additionally acquired from the tissue of the heart 23 using the electrodes 22. Thus, the processor can associate any given signal received from the electrodes 22, such as a bipolar EP signal, with the location from which the signal was acquired. The processor 28 receives the resulting signals via the electrical interface 35 and uses the information contained in these signals to construct an electrophysiological map 31 and an ECG trace 40, which are then presented on the display 26.

[0033] The processor 28 typically comprises a general-purpose computer together with software programmed to perform the functions described herein. The software can be downloaded to the computer in electronic form, for example, over a network, or alternatively or additionally, it can be provided and / or stored on a non-temporary physical medium such as magnetic memory, optical memory, or electronic memory. In particular, the processor 28 implements a dedicated algorithm disclosed herein, which is included in Figure 4, enabling the processor 28 to perform the steps of this disclosure, as further described below.

[0034] The examples shown in Figure 1 are selected solely for the purpose of illustrating the concept. Other types of electrophysiological sensing catheter geometry may be employed, such as the Lasso® catheter (manufactured by Biosense Webster, Inc., Irvine, California). Additionally, a contact sensor may be attached to the distal end of the mapping catheter 29 to transmit data indicating the physical quality of electrode contact with tissue. In embodiments, measurements from one or more electrodes 22 may be discarded if they indicate poor physical contact quality, while measurements from other electrodes may be considered valid if they indicate sufficient contact quality.

[0035] Annotation of delayed potentials containing local abnormal ventricular excitation (LAVA) signals. Figure 2 is a graph of surface electrocardiograms (ECGs) 60a and 60b, and a bipolar intracardiac potential graph 62, recorded using the system 21 of Figure 1 according to an embodiment of the present invention. Surface signals 60a and 60b are received from surface ECG electrodes, and the bipolar signal 62 is received from a pair of electrodes 22 of the catheter 29. Delayed ventricular excitations 63, 64a, and 64b are annotated on the bipolar signal. QRS complexes within the bipolar signal 66 are also annotated.

[0036] As can be seen, the highest correlation is observed between ECG signals and bipolar electrophoresis signals. However, bipolar electrophoresis signals may contain additional clinically important information, such as portions of delayed bipolar excitation that do not have a corresponding portion in the ECG signal.

[0037] Excitations 64a are within a predetermined time interval 55 and are identified using slide WOI 50 shown within the interval 55, all defined by the processor 28. The parameters of the interval 55 and slide WOI can be set by the user or by an algorithm to also take into account excitations 63 (which, when analyzed, are found to occur due to atrial pacing and are therefore irrelevant).

[0038] Using slide WOI50, which has the delayed potential algorithm described below, the processor 28 scans and analyzes the bipolar potential waveform 62 from late time to short time after the main annotation 66 until the scan point matches the main annotation point. The algorithm searches for delayed excitation candidates by searching from right to left within intervals 55. The delayed potential algorithm selects the most recent candidate that meets specific criteria. 1. It is not unrelated activity, such as other things seen in the ECG signal (e.g., far-field ventricular activity). 2. The bipolar signal amplitude exceeds a predetermined threshold. 3. The excitation is consistent with the previous beat and / or the next previous beat (i.e., it has a measure of temporal stability, as seen by the recurrence of signal annotation 64b that is consistent across the compared beats). 4. The most recent bipolar excitation that meets conditions 1-3 is selected within the WOI.

[0039] An additional fifth criterion may be established for stability by comparing the ECG signal morphology of the current heartbeat (measured from body surface electrodes or a patch) with that of a previous heartbeat. In other words, the heartbeat provided by the ECG signal morphology (e.g., linear shape) should be consistent (and imply the same chamber excitation sequence) so that conclusions can be drawn about delayed abnormal excitation from the bipolar intracardiac signal.

[0040] As shown in Figure 2, the examined bipolar excitations 63 were consistent with ECG excitations, and the processor used criterion 1 to rule out bipolar excitations from further consideration.

[0041] By applying criteria 1-4, the processor 28 identifies and annotates candidate delayed excitations indicating abnormal ventricular activity (64a). Additional graphical means and operations taken by the processor 28, such as calculating the LAT value of the annotated signals and presenting their respective tissue locations on the EP map, are shown in Figure 5b.

[0042] Description of LP and LAVA algorithms The following sections describe two variations of the algorithm described above, one for identifying general delayed potentials (LPs) and the other optimized for identifying LAVA subgroups of delayed potentials. The algorithm searches for abnormal ventricular bipolar excitations and, once identified, annotates them. In an additional step, the algorithm calculates the bipolar amplitude of the annotated LP / LAVA.

[0043] The user has several default parameters that affect the general algorithm. 1. A default minimum signal amplitude (mV) that is eligible for analysis. The threshold is used as a noise filter. 2. A delayed potential boundary defines the right side of the WOI scan (e.g., the latest data point at interval 55, considered using slide LP-WOI, as in WOI50 in Figure 2). The delayed potential boundary function affects the map and its points in the following ways: i. By default, boundary settings affect all points in the map when applied in real time during mapping. Users can modify the LP-WOI settings to affect only selected points or groups of points. ii. When multiple points are selected, the LP-WOI boundary can be adjusted to affect only the selected points. 3. A typical algorithm finds all wavefront (WF) annotation candidates according to the algorithm priority associated with the WF filter. This process results in all of the sampled signals (e.g., on some heartbeats) being candidates for annotation, such as annotations 64a and 64b in Figure 2.

[0044] For any given slide LP-WOI with a range of intervals, the algorithm counts the number of candidates within it. If the number exceeds X (e.g., X = 10 candidates), the algorithm classifies the waveform as a "noisy signal". If the candidate count exceeds Y (Y > X, e.g., Y = 20 candidates), the algorithm classifies the waveform as a "very noisy signal". Waveform portions classified as "very noisy" are dropped from the analysis. For "noisy signal" waveforms, only up to half (e.g., 5 out of 10) of the found candidates with the strongest dv / dt gradient are used for annotation. 4. The WOI slides and scans from its latest boundary to evaluate each WF annotation candidate to the LP boundary as a valid LP annotation. If a valid delayed potential annotation is found, it is confirmed using further criteria as described below. If it passes, it is marked as an LP annotation site and acquired for addition to the EP map. 5. Once a valid LP annotation found in the mapping WOI is defined by the delay boundary, the two previous beats of the acquired signal are checked to see if they meet the criteria, with the first previous beat being called "beat-1" and the second beat being called "beat-2". The following criteria are checked for both previous signals, but "passing" the criteria is required for only one of the previous beats. a. Pattern matching: Two previous heartbeats are examined to match the pattern of the mapping signal for the problem defined using body surface (BS) ECG signals. b. Timing of WF annotation candidates in the previous beat (beat-1) and the one before that (beat-2): The two previous beats are checked for the presence of WF annotation candidates based on similar timing frame criteria. For beat-1, the required accuracy is within a first time range, ±Δt1, e.g., ±10 msec, and for beat-2, the required accuracy is within a first time range, Δt2, typically Δt2 > Δt1, e.g., ±Δt2, ±20 msec. 6. Once a valid LP annotation is found to satisfy the two criteria above, the annotation site is used as the starting point for the delayed potential bipolar amplitude and is used to calculate the LP bipolar amplitude using one of the following two optional algorithms.

[0045] Option A i. From the LP annotation area, the dynamic V-WOI is calculated across the annotation area. The V-WOI is used to define the signal segment in which the maximum signal amplitude is measured. ii. The new algorithm explores annotation sites of "quiet segments" on its two sides, searching for X msec segments in the signal where the amplitude does not change more than Y mv (using the current values ​​as an example: X=10 msec and Y=0.02 msec). iii. The locations on both sides of the annotation region where the signal satisfies the conditions of section 5b define the boundary of section V-WOI where the signal is measured for the peak-to-peak maximum bipolar amplitude (mv). The maximum bipolar measurement is performed in the internal segment created by the V-WOI boundary.

[0046] Option B i. From the annotation site to each side, the signal's amplitude changes are explored using a "T" msec roving segment, where the peak-to-peak amplitude of the signal is measured and checked to see if it is smaller than a defined minimum amplitude "A". ii. If the inter-peak value is greater than "A", the roving segment moves 1 msec away from the annotation site and performs the above calculation. The process is performed on both sides of the annotation site. iii. If the inter-peak value is less than "A", the distal boundary of the roving segment is the V-WOI boundary (which occurs on both sides of the annotation site). The minimum V-WOI size is 10 msec. iv. For any instance where a roving segment reaches a “delay boundary” or “mapping WOI”, the V-WOI is defined at this location.

[0047] 7. If no delayed potential is found in the LP WOI segment defined by the delayed boundary, the annotation is searched in the previous segment of the mapping WOI, which means that it is searched from the previous boundary of the mapping WOI up to the defined delayed boundary (see below). a. In this segment, the legacy algorithm finds the WF annotation (e.g., the one with the strongest dv / dt), which is the annotation of this signal in question, if present. b. For the creation of the voltage map, the bipolar amplitude is calculated (from the previous boundary of the mapping WOI to the defined delay boundary and / or the full range of the WOI) and measured for peak-to-peak maximum bipolar (mv).

[0048] 8. If no annotation is found for the signal in question (meaning no LAT value (no-LAT point)), the bipolar value will not be calculated, and the point will not support voltage mapping.

[0049] LP points are algorithm annotation candidates that are found to be valid LP points, and support both LAT and voltage maps.

[0050] The LP bipolar value is the maximum peak-to-peak voltage within the defined LP V-WOI.

[0051] If the LP signal is not found in the LP WOI defined by the delay boundary, LAT LP=N / A LAT LAVA = Equal to the conventional LAT (when the conditions in Section 5 are met) LAVA V-WOI = Conventional V-WOI Bipolar LAVA = LAVA V-WOI Maximum Peak Voltage

[0052] Adaptation of optimized LAVA search algorithms Figure 3 is a graph of bipolar and monopolar electrocardiogram (ECG) signals analyzed to identify and annotate focal abnormal ventricular activity (LAVA) 80 according to an exemplary embodiment of the present invention.

[0053] The user has several default parameters that affect the LAVA detection algorithm. 1. To prevent the LAVA signal from being confused with the larger far-field amplitude of the QRS signal, and to prevent the annotation of noise signals smaller than the defined minimum, predefined minimum and maximum signal amplitudes (mV) are used to qualify for analysis. 2. The user-defined minimum duration of a valid LAVA signal that occurs after conventional annotation. Excitation points that fall below this defined duration are not classified as LAVA points. 3. The algorithm priority is based on the WF filter peak-to-peak value (mV).

[0054] The following further steps are taken to classify the candidate excitations as LAVA. 4. Configure V-WOI82 to measure the bipolar value of the annotated signal. 5. The algorithm uses section division in WOI to define and classify different LAVA signals according to their timing occurrences in WOI. - Available partitions starting from LAVA search limit 84, Below QRS partitioning 86, and early / delayed partitioning lines 88. - The user should be able to modify all LAVA division lines by dragging the early / delayed division lines 88 in the tip-search limit, LV division, and QRS division of the point ECG tool. 6. The algorithm calculates the time difference (msec) between the conventional signal annotation (e.g., of the QRS complex) and the found LAVA annotation. 7. The WOI is scanned in reverse, evaluating each wavefront (WF) annotation candidate as a valid LAVA annotation, and returning to the search limit of 84, or to a point defined as the blanking region of the LAVA signal (see below).

[0055] In the case of areas to be avoided (blanking of noisy areas), the algorithm continues scanning after the skipped blanking area before WOI to find a valid LAVA signal. 8. Each WF annotation candidate found is evaluated to satisfy the minimum and maximum absolute thresholds defined by the priority of valid LAVA signals (and conversely, for defined WOIs). 9. If the found LAVA annotation candidate is equal to the defined time difference (msec) in step 6, the annotation should be a conventional signal annotation. Otherwise, the annotation should be a LAVA annotation. 10. For each LAVA annotation point, the algorithm determines the maximum inter-peak voltage in the defined LAVA bipolar WOI according to these priorities. a. Maximum peak-to-peak value at the LAVA signal boundary (isoelectric section) according to the defined maximum noise amplitude and time segment (msec). The signal boundary is defined as very low (less than 0.03 mV over a 5 msec period). b. A defined LAVA V-WOI that opens around the annotation point. The C algorithm finds the minimum and maximum peaks for the defined annotation point gradient peak voltage. 11. Each WF annotation that passes through step 4 is further evaluated by the following:

[0056] If a LAVA signal is found, LAT LAVA = WF algorithm annotation candidate that has been found to be a valid LAVA.

[0057] Bipolar LAVA = The maximum peak-to-peak voltage within the defined bipolar LAVA V-WOI.

[0058] If the LAVA signal is not found LAT LAVA=N / A 12. Each WF annotation that passes through step 4 is further evaluated by the following:

[0059] If a LAVA signal is found, LAT LAVA = WF algorithm annotation candidate that has been found to be a valid LAVA.

[0060] Bipolar LAVA = The maximum peak-to-peak voltage within the defined bipolar LAVA V-WOI.

[0061] If the LAVA signal is not found LAT LAVA=N / A LAT LAVA = Equal to conventional LAT (when process 6 is satisfied) LAVA V-WOI = Conventional V-WOI Bipolar LAVA = LAVA V-WOI Maximum Peak Voltage

[0062] Method for detecting delayed potential Figure 4 is a schematic flowchart illustrating a method and algorithm for detecting abnormal ventricular activity in a bipolar electrophysics diagram according to an exemplary embodiment of the present invention. The algorithm according to the presented embodiment performs a process that begins in the bipolar data reception step 302, in which the processor 28 receives a bipolar signal (e.g., a waveform) from the catheter 29.

[0063] In the ECG data reception process 304, the processor 28 receives the respective ECG data from the surface electrodes.

[0064] Next, the processor 28 annotates two or more QRS groups in the bipolar waveform in the QRS annotation step 306. In some cases, if the exact points for annotating the QRS groups are not very clear in the bipolar signal, the processor may use the same annotated positions of the QRS groups on the ECG waveform.

[0065] Next, in the activity type confirmation step 307, the processor 28 confirms that the previous pulsations are of the same activity type, for example, by using the pattern matching method described above, in accordance with step 5 of the general algorithm described above.

[0066] Next, the processor 28 defines slide WOI 50 and operates the algorithm described above to detect one or more excitations in the bipolar signal within an interval 55 starting at a given time after each of the annotated QRS complexes in the bipolar excitation annotation step 308. Detection includes having an algorithm (not shown) that counts the number of candidates in order to classify and reject noisy signals.

[0067] In the bipolar excitation confirmation step 310, the processor 28 checks whether any of the annotated bipolar excitations match an ECG excitation. If the answer is yes, as seen in excitation 63 in Figure 2, the processor eliminates such bipolar excitation from further consideration, as seen in the excitation removal step 312. If the answer is no, as seen in excitation 64a, the processor estimates the repeatability of the bipolar excitation by checking whether the excitation recurred for at least a given number of cardiac cycles (e.g., by counting the number of excitations 64b) in the repeatability test step 314.

[0068] In the verification step 316, the processor 28 checks whether each of the remaining bipolar excitations meets the criteria of step 314. If the answer is no, the processor checks whether each of the remaining bipolar excitations meets the criteria by returning to step 314. In an optional embodiment, if no excitations that meet the criteria are found, the processor eliminates the bipolar excitations from further consideration by returning to the excitation elimination step 312.

[0069] If the answer is yes, the processor annotates the most recent repeatable bipolar excitation as a delayed potential (LP) initiated from ventricular tissue in the delayed potential annotation step 318.

[0070] Finally, as shown in Figure 5B, the processor 28 displays the annotated delay potentials on the EP map during the EP map generation process 320.

[0071] The exemplary flowchart shown in Figure 4 is selected solely for the purpose of clarifying the concept. This embodiment may also include additional algorithmic steps, such as simultaneously receiving multiple bipolar and ECG signals, and receiving an indicator of the degree of physical contact of the electrodes with the tissue being diagnosed from a contact force sensor. These steps and other possible steps have been intentionally omitted from the disclosure herein in order to provide a more simplified flowchart.

[0072] Normal and abnormal ventricular tissue in EP maps Figures 5A and 5B are schematic three-dimensional representations of electrophysiological (EP) maps 402 and 404 of the ventricle, showing completely normal tissue and partially abnormal tissue, respectively, according to embodiments of the present invention.

[0073] Figures 5A and 5B show ventricular tissue covered with local excitation time to arrival (LAT), color-coded using a color scale of 405. In the figures, grayscale is used instead of color. The EP map in Figure 5B was generated using the LAVA detection algorithm described above.

[0074] As can be seen, the surface tissue of the ventricular map in Figure 5A shows normal EP excitation wavefronts (WF) as a continuous, stepwise change in LAT values, as demonstrated by normal tissue.

[0075] On the other hand, the ventricular map in Figure 5B shows an isolated region 410 with an abnormally long LAT value due to delayed excitation. The abnormal tissue region 410 in Figure 5b is scar tissue that produces LAVA, which would require the aforementioned homogenization treatment by ablation, for example.

[0076] As can be seen, the disclosed technology allows physicians to clearly visualize the occurrence of ventricular tissue regions 410 that require life-saving treatment using an ablation catheter to eliminate arrhythmias resulting from abnormal tissue regions 410.

[0077] While the embodiments described herein primarily address cardiac diagnostic applications, the methods and systems described herein can also be used for other medical applications such as atrial tachycardia, or for early potential detection by performing a reverse mirror image algorithm (earliest instead of latest, left-to-right slide instead of right-to-left slide).

[0078] The embodiments described above are illustrative examples, and it will be understood that the present invention is not limited to those specifically illustrated and described above. Rather, the scope of the present invention includes both combinations and partial combinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art, which would be conceived by those skilled in the art upon reading the foregoing description.

[0079] [Implementation Method] (1) A method for annotating delayed potentials containing abnormal ventricular excitation signals, Receiving bipolar signals sensed by a pair of electrodes at a location within the patient's heart, Receiving one or more electrocardiogram (ECG) signals sensed by one or more surface electrodes attached to the patient, In the aforementioned bipolar signal, two or more consecutive QRS groups are identified, In the bipolar signal, one or more excitations occurring within a window of interest that starts at a given time for the identified QRS group are detected. (i) whether the one or more excitations do not coincide with a predetermined event observed in the one or more ECG signals, and (ii) whether the one or more excitations are repeatable in the consecutive QRS group, thereby confirming whether the detected one or more excitations are delayed potentials, A method comprising: determining that at least one of the detected one or more excitations is a delayed potential, and then making the most recent of the at least one of the one or more delayed potentials visible to the user. (2) The method according to Embodiment 1, wherein visualizing the latest delayed potential includes graphically displaying the latest delayed potential on an electrophysiological (EP) map in relation to the positions of the pair of electrodes in the heart. (3) The method according to Embodiment 1, wherein visualizing the latest delayed potential includes annotating the latest delayed potential. (4) The method according to Embodiment 1, wherein the predetermined event includes excitation observed in the one or more ECG signals. (5) The method according to Embodiment 1, wherein the predetermined event includes fractionation observed in the one or more ECG signals.

[0080] (6) The method according to Embodiment 1, wherein verifying whether the one or more excitations are repeatable includes verifying whether the one or more excitations recur in at least a given number of cardiac cycles. (7) The method of embodiment 6, wherein verifying whether the one or more excitations recur includes using pattern matching. (8) The method according to Embodiment 1, wherein the latest delayed potential includes a localized abnormal ventricular activity (LAVA) signal. (9) The method according to Embodiment 1, wherein detecting the excitation includes applying filtration to smooth the bipolar signal and detecting in the smoothed bipolar signal one or more excitations having an amplitude above a given threshold. (10) The method according to Embodiment 1, wherein the received bipolar signal includes a ventricular bipolar signal acquired by a catheter electrode.

[0081] (11) Receiving a unipolar signal at the aforementioned position and identifying two or more consecutive QRS groups in the unipolar signal, In the unipolar signal, one or more excitations occurring within a window of interest that starts at a given time for the identified QRS group are detected. (i) whether the one or more excitations do not coincide with a predetermined event observed in the one or more ECG signals, and (ii) whether the one or more excitations are repeatable in the consecutive QRS group, thereby confirming whether the detected one or more excitations are delayed potentials, The method according to Embodiment 1, comprising: in response to determining that at least one of the detected one or more excitations is a delayed potential, visualizing to the user the most recent of the at least one of the one or more delayed potentials. (12) The method according to Embodiment 1, wherein it is performed in real time to determine whether the detected one or more excitations are delayed potentials. (13) The method according to Embodiment 1, comprising modifying parameters used to identify, detect, verify, determine, and visualize the signal. (14) A device for annotating delayed potentials including abnormal ventricular excitation signals, It is an interface, The system receives bipolar signals sensed by a pair of electrodes at a location within the patient's heart. An interface configured to receive one or more electrocardiogram (ECG) signals sensed by one or more body surface electrodes attached to the patient, It is a processor, In the aforementioned bipolar signal, two or more consecutive QRS groups are identified, In the bipolar signal, one or more excitations occurring within a window of interest that starts at least a given time are detected for the identified QRS group. (i) whether the one or more excitations do not coincide with a predetermined event observed in the one or more ECG signals, and (ii) whether the one or more excitations are repeatable in the consecutive QRS group, thereby confirming whether the detected one or more excitations are delayed potentials, A device comprising: a processor configured to visualize to the user the most recent of the at least one of the detected one or more excitations, in response to determining that at least one of the detected one or more excitations is a delayed potential. (15) The apparatus according to Embodiment 14, wherein the processor is configured to visualize the latest delayed potential by graphically displaying the latest delayed potential on an electrophysiological (EP) map in relation to the positions of the pair of electrodes in the heart.

[0082] (16) The apparatus according to embodiment 14, wherein the processor is configured to visualize the latest delay potential by annotating the latest delay potential. (17) The apparatus according to Embodiment 14, wherein the predetermined event includes excitation observed in one or more ECG signals. (18) The apparatus according to Embodiment 14, wherein the predetermined event includes fractionation observed in the one or more ECG signals. (19) The apparatus according to Embodiment 14, wherein the processor is configured to verify whether the one or more excitations are repeatable by verifying whether the one or more excitations recur in at least a given number of cardiac cycles. (20) The apparatus according to embodiment 19, wherein the processor is configured to verify whether the one or more excitations recur by using pattern matching.

[0083] (21) The apparatus according to Embodiment 14, wherein the latest delayed potential includes a localized abnormal ventricular activity (LAVA) signal. (22) The apparatus according to Embodiment 14, wherein the processor is configured to detect excitation by applying filtration to smooth the bipolar signal and detecting one or more excitations having an amplitude above a given threshold in the smoothed bipolar signal. (23) The apparatus according to Embodiment 14, wherein the received bipolar signal includes a ventricular bipolar signal acquired by a catheter electrode. (24) The interface is further configured to receive a unipolar signal at the position, and the processor In the aforementioned unipolar signal, two or more consecutive QRS groups are identified, In the unipolar signal, one or more excitations occurring within a window of interest that starts at least a given time are detected for the identified QRS group. (i) whether the one or more excitations do not coincide with a predetermined event observed in the one or more ECG signals, and (ii) whether the one or more excitations are repeatable in the consecutive QRS group, thereby confirming whether the detected one or more excitations are delayed potentials, The apparatus according to Embodiment 14, further configured to visualize to the user the most recent of the at least one of the detected excitations, in response to determining that at least one of the detected excitations is a delayed potential. (25) The apparatus according to Embodiment 14, wherein the processor is configured to determine in real time whether the detected one or more excitations are delayed potentials.

[0084] (26) The apparatus according to Embodiment 14, wherein the processor is further configured to modify parameters used for identifying, detecting, verifying, determining, and visualizing the signals.

Claims

1. A device for annotating delayed potentials containing abnormal ventricular excitation signals, It is an interface, The system receives bipolar signals sensed by a pair of electrodes at a location within the patient's heart. An interface configured to receive one or more electrocardiogram (ECG) signals sensed by one or more surface electrodes attached to the patient, It is a processor, In the aforementioned bipolar signal, two or more consecutive QRS groups are identified, In the bipolar signal, one or more excitations occurring within a window of interest that starts at least a given time are detected for the identified QRS group. (i) verify whether the one or more excitations do not match a predetermined event which includes at least one excitation or fractionation observed in the one or more ECG signals observed in the one or more ECG signals, and if they match a predetermined event, exclude the excitation from further consideration, select only the excitations that do not match a predetermined event, and (ii) verify whether the one or more excitations that were detected are delayed potentials of ventricular tissue by verifying whether the selected one or more excitations are repeatable in the consecutive QRS group by verifying whether they recurred over a given number of cardiac cycles, and A device comprising: a processor configured to visualize to the user the most recent of the at least one of the detected one or more excitations, in response to determining that at least one of the detected one or more excitations is a delayed potential.

2. The apparatus according to claim 1, wherein the processor is configured to visualize the latest delayed potential by graphically displaying the latest delayed potential on an electrophysiological (EP) map in relation to the positions of the pair of electrodes in the heart.

3. The apparatus according to claim 1, wherein the processor is configured to visualize the latest delay potential by annotating the latest delay potential.

4. The apparatus according to claim 1, wherein the predetermined event includes excitation observed in the one or more ECG signals.

5. The apparatus according to claim 1, wherein the predetermined event includes fractionation observed in the one or more ECG signals.

6. The apparatus according to claim 1, wherein the processor is configured to verify whether the one or more excitations are repeatable by verifying whether the one or more excitations recur in at least a given number of cardiac cycles.

7. The apparatus according to claim 6, wherein the processor is configured to verify whether the one or more excitations recur by using pattern matching.

8. The apparatus according to claim 1, wherein the latest delayed potential includes a localized abnormal ventricular activity (LAVA) signal.

9. The apparatus according to claim 1, wherein the processor is configured to detect excitation by applying filtration to smooth the bipolar signal and detecting one or more excitations having an amplitude exceeding a given threshold in the smoothed bipolar signal.

10. The apparatus according to claim 1, wherein the received bipolar signal includes a ventricular bipolar signal acquired by a catheter electrode.

11. The interface is further configured to receive a unipolar signal at the position, and the processor, In the aforementioned unipolar signal, two or more consecutive QRS groups are identified, In the unipolar signal, one or more excitations occurring within a window of interest starting at a given time are detected for the identified QRS group. (i) whether the one or more excitations do not coincide with a predetermined event observed in the one or more ECG signals, and (ii) whether the one or more excitations are repeatable in the consecutive QRS group, thereby confirming whether the detected one or more excitations are delayed potentials, The apparatus according to claim 1, further configured to visualize to the user the most recent of the at least one of the detected excitations, in response to determining that at least one of the detected excitations is a delayed potential.

12. The apparatus according to claim 1, wherein the processor is configured to determine in real time whether the detected one or more excitations are delayed potentials.

13. The apparatus according to claim 1, wherein the processor is further configured to modify parameters used for identifying, detecting, verifying, determining, and visualizing the bipolar signal and the one or more ECG signals.

14. A program for annotating delayed potentials containing abnormal ventricular excitation signals, When the program is loaded into the processor, the processor receives a bipolar signal sensed by a pair of electrodes at a location within the patient's heart. Receiving one or more electrocardiogram (ECG) signals sensed by one or more surface electrodes attached to the patient, In the aforementioned bipolar signal, two or more consecutive QRS groups are identified, In the bipolar signal, one or more excitations occurring within a window of interest starting at a given time for the identified QRS group are detected. (i) verify whether the one or more excitations do not coincide with a predetermined event which includes at least one excitation or fractionation observed in the one or more ECG signals, and if they do coincide with a predetermined event, exclude the excitation from further consideration, select only the excitations which do not coincide with a predetermined event, and (ii) verify whether the one or more excitations detected are delayed potentials of ventricular tissue by verifying whether they are repeatable in the consecutive QRS group by verifying whether they recurred over a given number of cardiac cycles, A program that, in response to determining that at least one of the detected one or more excitations is a delayed potential, causes the user to visualize the most recent of the at least one of the one or more delayed potentials.

15. The program according to claim 14, wherein visualizing the latest delayed potential includes graphically displaying the latest delayed potential on an electrophysiological (EP) map in relation to the positions of the pair of electrodes in the heart.

16. The program according to claim 14, wherein visualizing the latest delay potential includes annotating the latest delay potential.

17. The program according to claim 14, wherein the predetermined event includes excitation observed in one or more ECG signals.

18. The program according to claim 14, wherein the predetermined event includes fractionation observed in the one or more ECG signals.

19. The program according to claim 14, wherein verifying whether the one or more excitations are repeatable includes verifying whether the one or more excitations recur in at least a given number of cardiac cycles.

20. The program according to claim 19, wherein verifying whether one or more of the excitations recur includes using pattern matching.

21. The program according to claim 14, wherein the latest delayed potential includes a localized abnormal ventricular activity (LAVA) signal.

22. The program according to claim 14, wherein detecting the excitation includes applying filtration to smooth the bipolar signal and detecting one or more excitations having an amplitude above a given threshold in the smoothed bipolar signal.

23. The program according to claim 14, wherein the received bipolar signal includes a ventricular bipolar signal acquired by a catheter electrode.

24. When the program is loaded into the processor, the processor further: The process involves receiving a unipolar signal at the aforementioned location and identifying two or more consecutive QRS groups in the unipolar signal. In the unipolar signal, one or more excitations occurring within a window of interest starting at a given time for the identified QRS group are detected. (i) whether the one or more excitations do not coincide with a predetermined event observed in the one or more ECG signals, and (ii) whether the one or more excitations are repeatable in the consecutive QRS group, thereby confirming whether the detected one or more excitations are delayed potentials, The program according to claim 14, which, in response to determining that at least one of the detected one or more excitations is a delayed potential, causes the user to visualize the most recent of the at least one of the one or more delayed potentials.

25. The program according to claim 14, wherein it is performed in real time to determine whether the detected one or more excitations are delayed potentials.

26. When the program is loaded into the processor, the processor further: The program according to claim 14, which causes the program to modify parameters used to identify, detect, verify, determine, and visualize the bipolar signal and the one or more ECG signals.

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