Detection of electrophysiological (EP) conduction gaps in the ablation line

Abstract

The system includes an interface and a processor. The interface is configured to receive a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve within a chamber of the patient's heart. The processor is configured to (i) generate local conduction vectors (LCVs) for the region based on the plurality of EP signals, (ii) estimate a level of variation between a set of LCVs along the ablation curve within the tissue region, and (iii) identify the presence of a conduction gap in the ablation curve based on the level of variation.

Description

[Technical Field]

[0001] The present disclosure relates generally to the acquisition and analysis of electrophysiological (EP) signals, and more particularly to methods for identifying arrhythmogenic pathways using EP data acquired by an EP mapping catheter. [Background technology]

[0002] Identifying arrhythmogenic tissue pathways in cardiac tissue using mapping catheters has previously been proposed in the patent literature. For example, International Publication No. 2020 / 227469 describes how pulmonary vein isolation (PVI) has become the first-line treatment for symptomatic, drug-refractory atrial fibrillation (AF). In conjunction with the PVI procedure, linear ablation lesions are created to achieve PV isolation. Electrophysiological maps created from data collected with a high-density grid catheter can be used to identify relevant conduction gaps within peripheral pulmonary vein isolation lesions.

[0003] As another example, U.S. Patent Application Publication No. 2019 / 0125438 describes a method and system for gap detection in an ablation line. Microelectrodes are implemented at the distal tip of a catheter to provide localized gap detection along the ablation line. A pacing protocol is used to sequence each microelectrode pair at a tissue location. If biological tissue is present, the pacing signal propagates through the biological tissue to deliver a pulse to the heart. The operator sees a captured signal and knows there is a gap in the ablation line. Pacing and ablation are performed at the same location without the need to switch instruments and / or catheters.

[0004] U.S. Patent No. 10,792,087 describes a method for assessing gaps in ablation lesions, which method is based on estimating the temporal relationship between stimulation and sensed activation peaks, and the spatial relationship between stimulation and sensing locations. In this way, one of multiple electrodes of a sensing catheter that is proximal to the gap in the lesion is identified. A map of the body cavity is displayed, with the identified electrode marked on the map.

[0005] In a paper incorporated herein by reference, entitled "Propagation Vectors Facilitate Differentiation Between Conduction Block, Slow Conduction, and Wavefront Collision" (Circulation: Arrhythmia and Electrophysiology, Vol. 14, pp. 741-550, August 2021, Yavin et al.) describes a method in which propagation vectors are generated from unipolar waveforms of adjacent electrodes along and across a catheter array spline acquired in a single beat. To investigate the utility of propagation vectors for detecting conduction block during ablation, a Cavo-tricuspid isthmus line was created by placing the array lateral to the line during coronary sinus pacing. Real-time propagation vectors were confirmed to improve the ability of standard activation maps to distinguish complex conduction patterns, including determining conduction block during ablation.

[0006] A more complete understanding of the present disclosure will be obtained from the following detailed description of the embodiments of the present disclosure when read in conjunction with the drawings. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic, pictorial illustration of a catheter-based electrophysiological (EP) mapping and ablation system, according to an example of the present disclosure. [Figure 2A]10 is a rendering of an EP map of a ventricle overlaid with respective sets of local conduction vectors (LCVs) showing abrupt changes between sets indicating an ablation gap, according to an example of the present disclosure. [Figure 2B] 10 is a rendering of an EP map of a ventricle overlaid with respective sets of local conduction vectors (LCVs) showing abrupt changes between sets indicating an ablation gap, according to an example of the present disclosure. [Figure 3A] 10A-10C are renderings of EP maps of a ventricle showing approximately anti-parallel LCVs indicating continuous ablation and approximately orthogonal LCVs indicating gaps in the ablation, respectively, according to one embodiment of the present disclosure. [Figure 3B] 10A-10C are renderings of EP maps of a ventricle showing approximately anti-parallel LCVs indicating continuous ablation and approximately orthogonal LCVs indicating gaps in the ablation, respectively, according to one embodiment of the present disclosure. [Figure 4] 1 is a flowchart that schematically illustrates a method for identifying an ablation gap by finding an abrupt change in LCV, according to an embodiment of the present disclosure. [Figure 5] 10 is a flowchart that schematically illustrates a method for identifying an ablation gap using the absolute orientation of an LCV, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] overview Catheter-based cardiac ablation may not completely terminate arrhythmias as planned. For example, atrial fibrillation (AF) may persist despite pulmonary vein isolation (PVI) performed by ablating PV ostium tissue along a curve that completely surrounds the PV ostium. Persistence of arrhythmia may occur due to incomplete ablation, leaving one or more undesirable gaps between otherwise contiguous ablation sites.

[0009] Typically, incomplete ablation requires follow-up ablation. Additional ablations are best performed during the same invasive procedure, i.e., immediately after confirming and identifying the gap following the first ablation. However, it can be difficult to identify the location of the gap along the ablation curve (the term "ablation line" is also used to refer to the same path of ablation along the curve).

[0010] One possible way to obtain an indication of the location of the gap is by mapping EP propagation in cardiac tissue. Propagation is analyzed from multiple EP data points acquired by a mapping catheter, with each data point including an electrogram and the location on the tissue from which the electrogram was acquired. Data points are acquired from each electrode on the catheter, and acquisition is performed automatically without user intervention.

[0011] For example, using these data points, a processor may calculate a local conduction vector (LCV), which alone may indicate a gap. However, this representation is often vague and inaccurate. Due to the natural variance in the distribution of EP activation propagation vectors (e.g., LCVs), analysis can be difficult and interpretation can be ambiguous.

[0012] Therefore, to identify the exact location of the gap, physicians must (a) go beyond the target area and sometimes (b) apply additional techniques such as pacing, which is time-consuming. When using pacing, amplitudes at different timings and / or locations are compared. Searching for gaps based on amplitude leads to many false positives. However, pacing techniques alone cannot pinpoint the exact location of the gap.

[0013] One attempt to improve the analysis is described in U.S. Patent Application No. 17 / 481,616, filed September 22, 2021, entitled "Finding a Cardiac Line of Block Using Statistical Analysis of Activation Wave Velocity." The application describes a method that includes receiving a set of data points including the locations and respective velocities of activation waves in a tissue region of a cardiac chamber. The set is divided into at least two velocity clusters, each characterized by a respective velocity of the activation waves. One or more boundary curves are estimated between the at least two clusters. The one or more boundary curves are presented to a user as possible lines of block of the activation waves.

[0014] The embodiments of the present disclosure described herein provide the user with the technique to easily detect any gaps in the ablation line in a manner that allows for immediate re-ablation.

[0015] In one embodiment, the processor identifies an ablation gap by detecting an abrupt change in the LCV as the ablation line is scanned (e.g., traced by a physician) using the catheter, where the detected abrupt change in the direction and / or extent of the LCV indicates the presence of an ablation gap therein or nearby.

[0016] To estimate how abrupt a detected change in the direction and / or magnitude of an LCV is, in some embodiments, a metric E(a,b) is defined between groups a and b of LCVs. For example, V a Let us consider all vectors in the group a of LCV.

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[0021] The value of E(a,b) is in the range [0,1], where 0 indicates a perfect match and 1 indicates a perfect opposite. If the metric value is greater than a predefined threshold c, E(a,b)>c,c>0, a gap is indicated to the user. Other metrics are proposed below.

[0022] In other examples, the processor executes an algorithm that compares the direction of the LCV vector to the local tangent of the ablation line. The algorithm runs in real time and may be used with or without pacing.

[0023] In some examples, to find the ablation gap, the processor performs the following steps after ablation and before beginning the gap identification process. 1. Calculate an ablation line and display it on the EP map. The ablation line can be calculated, for example, by interpolating across a set of tags that mark the location of each of the ablation tissue sites (e.g., spots). First, using the GUI, a line (e.g., a path) is displayed, in one example, as a dashed pattern. 2. Guide the physician (e.g., using a GUI) to navigate the catheter along the displayed ablation path. In this example, the covered portion of the (analyzed) path is shown as a solid line. 3. Detect one or more ablation gaps along the path. 4. Marking gaps detected in the path during navigation on the EP map (e.g., with red lines). This step may include overlaying the LCV on the EP map.

[0024] In one example, gap detection step (3) is based on calculating the aforementioned LCV as the mapping catheter traces the ablation line. With high probability, when no gaps exist along the ablation line, the LCV is expected to be (on average) more parallel to the ablation line direction. On the other hand, whenever a gap exists, the LCV is expected to be oriented in a direction approximately perpendicular (i.e., approximately orthogonal) to the ablation line at the location of the gap.

[0025] The aforementioned level of LCV orthogonality check can be performed in an automated manner by comparing the direction tangent to the defined ablation path with the average direction of the LCV along the line segment being examined. All LCV-related calculations are performed in the background and are not necessarily displayed. Detected conduction gaps are visually indicated by special highlighting on the map.

[0026] Finally, as a backup method that may be used with catheters that may not contain sufficient acquisition power to calculate LCV, the processor may analyze bipolar EP values ​​acquired along the ablation line. Local extrema in the bipolar signal change may be a clue to a gap at that location.

[0027] System Description FIG. 1 is a schematic, pictorial illustration of a catheter-based electrophysiological (EP) mapping and ablation system 10 according to an embodiment of the present disclosure.

[0028] The system 10 includes multiple catheters that are percutaneously inserted by a physician 24 through the patient's vascular system into the cavities or vasculature of the heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location in the heart 12. Multiple catheters can then be inserted into the delivery sheath catheter to reach the desired location. The multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters dedicated to both sensing and ablation. An exemplary catheter 14 configured for sensing IEGMs is illustrated herein. The physician 24 brings a distal tip 28 (hereinafter also referred to as a distal end assembly 28) of the catheter 14 into contact with the heart wall to sense a target site in the heart 12. For ablation, the physician 24 similarly delivers the distal end of an ablation catheter to the target site for ablation.

[0029] Catheter 14 is an exemplary catheter that includes one, and preferably multiple, electrodes 26 optionally distributed across multiple splines 22 at distal tip 28 and configured to sense IEGM signals. Catheter 14 may additionally include a position sensor 29 embedded in or near distal tip 28 for tracking the position and orientation of distal tip 28. Optionally and preferably, position sensor 29 is a magnetic-based position sensor that includes three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0030] The magnetic-based position sensor 29 may operate in conjunction with a location pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field within a predetermined working volume. The real-time position of the distal tip 28 of the catheter 14 may be tracked based on the magnetic fields generated by the location pad 25 and sensed by the magnetic-based position sensor 29. Details of magnetic-based position sensing technology are described in U.S. Patent Nos. 5,5391,199; 5,443,489; 5,558,091; 6,172,499; 6,239,724; 6,332,089; 6,484,118; 6,618,612; 6,690,963; 6,788,967; and 6,892,091.

[0031] The system 10 includes one or more electrode patches 38 positioned for skin contact on the patient 23 to establish a position reference for the location pads 25 and impedance-based tracking of the electrodes 26. For impedance-based tracking, current is directed to the electrodes 26 and sensed at the electrode skin patches 38, allowing the position of each electrode to be triangulated via the electrode patches 38. Details of impedance-based position tracking techniques are described in U.S. Patent Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0032] Recorder 11 displays electrograms 21 captured by body surface ECG electrodes 18 and intracardiac electrograms (IEGMs) captured by electrodes 26 on catheter 14. Recorder 11 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0033] The system 10 may include an ablation energy generator 50 adapted to deliver ablation energy to one or more electrodes at the distal tip of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radiofrequency (RF) energy or pulsed field ablation (PFA) energy, including unipolar or bipolar high-voltage DC pulses, such as may be used to effect irreversible electroporation (IRE), or a combination thereof.

[0034] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between the catheters, the electrophysiology equipment, a power source, and a workstation 55 that controls the operation of the system 10. The electrophysiology equipment of the system 10 may include, for example, multiple catheters, location pads 25, body surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 additionally includes processing capabilities for implementing real-time calculations of catheter position and performing ECG calculations.

[0035] The workstation 55 includes a memory 57, a processor 56 unit having memory or storage loaded with appropriate operating software, and user interface functionality. The workstation 55 may optionally provide multiple functions, including: (1) modeling the endocardial anatomical structure in three dimensions (3D) and rendering a model or anatomical map 20 for display on a display device 27; (2) displaying activation sequences (or other data) compiled from recorded electrograms 21 in a representative visual representation or image superimposed on the rendered anatomical map 20 on the display device 27; (3) displaying the real-time position and orientation of multiple catheters within the cardiac chambers; and (5) displaying areas of interest, such as where ablation energy is being applied, on the display device 27. One commercially available product embodying each element of the system 10 is available as the CARTO™ 3 system, commercially available from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0036] In some embodiments, processor 56 typically comprises a general-purpose computer that is programmed with software to perform the functions described herein. The software may be downloaded to the computer in electronic form, for example, over a network, or alternatively or additionally, may be provided and / or stored on non-transitory, tangible media, such as magnetic, optical, or electronic memory.

[0037] This particular configuration of system 10 is presented as an example to illustrate the particular problem addressed by embodiments of the present disclosure and to demonstrate the application of these embodiments in improving the performance of such systems. However, embodiments of the present disclosure are in no way limited to this particular type of exemplary system, and the principles described herein may be applied to other types of medical systems as well. For example, other types of multi-electrode catheters, such as an octaray™ catheter or a basket catheter, may be used.

[0038] Identifying ablation gaps along the ablation path by detecting sudden changes in LCV To identify the ablation gap, the physician may perform EP mapping along the ablation line, for example, by moving the distal end assembly 28 of the mapping catheter 14 from the initial ablation site. As described above, the entire path is initially displayed as a dashed line. The processor, for example, using a GUI, guides the physician on the direction to move the mapping catheter along the path. The portion of the path traversed by the mapping catheter is displayed continuously in FIG. 3.

[0039] Also seen is an ablation catheter 231 with an ablation electrode 232. This catheter was used in the first ablation, which was checked for continuity. Catheter 231 will be used for follow-up ablations to close any conduction gaps found using the disclosed techniques.

[0040] 2A and 2B are renderings of a ventricular EP map 225 overlaid with respective sets 221 and 222 of local conduction vectors (LCVs) showing abrupt changes between the sets indicative of an ablation gap, according to one example of the present disclosure. The abrupt changes in direction occur at tissue sites along an ablation line 230.

[0041] To accomplish this, a system such as system 10 includes an interface configured to receive multiple electrophysiological (EP) signals from a tissue region along an ablation curve within a chamber of a patient's heart. A processor of system 10 is configured to (i) present the ablation curve to a user from which the multiple EP signals are acquired, (ii) generate local conduction vectors (LCVs) for the region based on the multiple EP signals, (iii) estimate a level of change between a set of LCVs along the ablation curve within the region, and (iv) indicate the presence of a conduction gap in the ablation curve based on the level of change. The processor is configured to estimate the level of change by comparing the level of change to a predetermined change threshold.

[0042] The processor is configured to estimate a level of variation by generating a representative LCV for each set and estimating a level of variation between the representative LCVs. The estimating of variation may involve using one of the metrics described below.

[0043] Metrics for measuring changes in LCV At each LCV calculation frame number k (e.g., each heartbeat), the 3D vector for each electrode i, i≦n

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[0046] To identify the overall vector change between frames, several metrics can be considered.

[0047] Two frames a and b (respectively, vectors

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[0050] V a All vectors

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[0054] Another applicable metric is to use the L2 distance metric on the angular change between corresponding vectors on the frames, but this metric is somewhat computationally expensive.

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[0057] Other metrics besides L2 can also be used, e.g.

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[0059] For stability, the above calculations do not necessarily have to be performed between two consecutive frames, but rather between two averages of several frames. For example, each vector of every three consecutive frames is averaged and a comparison is made (the above calculated metric is performed between two subsequent averages (with six frames)).

[0060] Identifying ablation gaps along the ablation path by estimating the absolute orientation of the LCV 3A and 3B are renderings of EP maps 227 and 327 of ventricles 257 and 357, respectively, showing antiparallel LCVs (261, 271) indicating continuous ablation according to an embodiment of the present disclosure, and showing approximately orthogonal LCVs (281, 282) indicating gaps in the ablation according to an embodiment of the present disclosure.

[0061] In Figure 3A, the distal tip assembly 28 of the catheter 14 of Figure 1 is advanced distally along a processor-drawn ablation line 250. As can be seen, a portion 252 of the line 250 that has already been checked using the electrodes of the distal tip assembly is marked as a solid line, while the remaining portion 253 is still displayed as a dashed line. In the example shown in Figure 3A, the LCVs of the vector sets (261, 271) on either side of portion 252 of the ablation line 250 are oriented approximately antiparallel to each other. Parallel or antiparallel EP propagation vectors on either side of the ablation line indicate with a high probability that ablation is complete there, e.g., there is no conduction gap.

[0062] In FIG. 3B, the distal tip assembly 28 of the catheter 14 of FIG. 1 is pulled proximally along an ablation line 350. As can be seen, a portion 352 of the line 350 that was previously checked using the electrodes of the distal tip assembly is marked as a solid line, while the remaining portion 353 is still dashed. In the example shown in FIG. 3B, some vectors of the vector set (271, 281) on either side of portion 252 of the ablation line 250 are oriented nearly perpendicular to the ablation line therein. This is exemplified at location 349, where angle 370 between tangent line 355 and LCV direction 360 is close enough to 90 degrees that location 349 is part of a gap. The presence of EP propagation vectors nearly perpendicular to the ablation line indicates a high probability that the ablation is incomplete, e.g., that one or more conduction gaps exist therein.

[0063] The location of the conduction gap is indicated by having a portion 390 of the ablation line 350 highlighted by the processor. By way of example, the highlighting may change the color of the line segment 390 (e.g., from black to red).

[0064] Method for identifying an ablation gap along an ablation path - Patents.com 4 is a flow chart that schematically illustrates a method for identifying an ablation gap by detecting an ablation gap change in LCV, according to one embodiment of the present disclosure. According to the presented example, the algorithm executes a process that begins with acquiring EP data points along an ablation line within a cardiac chamber, such as cardiac chamber 225, in EP data acquisition step 402 using system 10 and flat catheter assembly 28 of FIG. 1. To this end, processor 56 displays ablation line 230 overlaid on the EP map, as shown in FIG. 2, and uses graphical tools such as those described in connection with FIG. 3 to guide the physician in real time as to where to move the mapping catheter to acquire the relevant EP data points.

[0065] In the EP data analysis step 404, the processor 56 executes a program to generate local conduction vectors (LCVs) such as those seen in FIG.

[0066] In the next LCV analysis step 406, the processor estimates a metric E(a,b) along the ablation curve, such as one of the metrics described above.

[0067] In orthogonality check 408, the processor compares the detected level of orthogonality with a predetermined threshold (e.g., a minimum predetermined angle). Orthogonality is measured relative to the ablation line direction at the catheter's location. In such cases, a metric is used to measure whether the vectors are approximately orthogonal. The metric is V a Vector (LCV) as V b It can also be used between the tangent vector (direction) of a curve as

[0068] In this case, the algorithm can take into account the degree to which most of the vectors are orthogonal to the path direction as an alternative to using a metric. The check may be done statistically (e.g., by checking a running average for orthogonality) for each LCV or for a local set of LCVs.

[0069] If the level of orthogonality exceeds a threshold, processor 56 indicates the presence of a conduction gap in the ablation curve in a gap indication step 410 .

[0070] In either case, the process returns to step 402 as long as the mapping catheter is moving along the ablation line.

[0071] 5 is a flow chart that schematically illustrates a method for identifying an ablation gap using the absolute orientation of the LCV, according to one embodiment of the present disclosure. According to the presented example, the algorithm executes a process that begins, in EP data acquisition step 502, with acquiring EP data points along an ablation line within a heart chamber, such as heart chamber 357, using system 10 and flat catheter assembly 28 of FIG. 1. To this end, processor 56 displays the ablation line overlaid on the EP map, as shown in FIGS. 2 and 3, and uses graphical tools such as those described in connection with FIGS. 2 and 3 to guide the physician in real time as to where to move the mapping catheter to acquire the relevant EP data points.

[0072] In the EP data analysis step 504, the processor 56 executes a program to generate local conduction vectors (LCVs) such as those seen in FIGS.

[0073] In the next LCV analysis step 506, the processor estimates the level of orthogonality of the LCV to one or more tangents to the ablation curve.

[0074] In orthogonality check 508, the processor compares the detected level of orthogonality with a predetermined threshold (e.g., a minimum predetermined angle). The check may be performed in a statistical manner (e.g., by checking a running average of orthogonality), for each LCV, or for a local set of LCVs.

[0075] If the level of orthogonality exceeds a threshold, processor 56 indicates the presence of a conduction gap in the ablation curve in a gap indication step 510 .

[0076] In either case, the process returns to step 502 as long as the mapping catheter is moving along the ablation line.

[0077] The flowcharts shown in Figures 4 and 5 have been chosen purely for purposes of conceptual clarity. This embodiment may also include additional steps in the algorithm, such as preselecting input EGMs based on an indication from a force sensor of the degree of physical contact of the electrodes with the diagnosed tissue. This step, and other possible steps, have been intentionally omitted from the disclosure herein to provide a more simplified flowchart. [Example]

[0078] Example 1 The system (10) includes an interface (30) and a processor (56). The interface is configured to receive a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve (230, 250) within a ventricle (257, 357) of a heart (12) of a patient (23). The processor is configured to (i) generate local conduction vectors (LCVs) (221, 222) for the region based on the plurality of EP signals, (ii) estimate a level of variation between a set of LCVs along the ablation curve within the tissue region, and (iii) identify the presence of a conduction gap (390) in the ablation curve based on the level of variation.

[0079] Example 2 10. The system of claim 1, wherein the processor is configured to identify gaps by comparing the level of variation to a predetermined variation threshold.

[0080] Example 3 A system (10) as described in any one of Examples 1 and 2, wherein the processor (56) is configured to estimate the level of change by estimating one or both of (i) a change in direction and (ii) a change in magnitude of the LCV (221, 222).

[0081] Example 4 A system (10) described in any one of Examples 1 to 3, wherein the processor (56) is configured to estimate the level of variation by generating a representative LCV for each set (221, 222) and estimating the level of variation between the representative LCVs.

[0082] Example 5 A system (10) as described in any one of Examples 1 to 4, wherein the processor (56) is configured to present the ablation curve (230, 250) to a user by interpolating across a set of tags marking the respective locations of the ablation tissue sites and presenting the resulting interpolated curve.

[0083] Example 6 The system (10) of any one of Examples 1 to 5, wherein the plurality of electrophysiological (EP) signals are one of unipolar and bipolar electrograms acquired using a multi-electrode mapping catheter (14).

[0084] Example 7 7. The system (10) of any one of Examples 1 to 6, wherein the ablation lines (230, 250) are ablation curves that run around the ostia of the pulmonary veins (PV).

[0085] Example 8 The system (10) includes an interface (30) and a processor (56). The interface (30) is configured to receive a plurality of electrophysiological (EP) signals acquired at a tissue region along an ablation curve (230, 250) within a ventricle (257, 357) of a heart (12) of a patient (23). The processor (56) is configured to (i) generate local conduction vectors (LCVs) (261, 271, 281, 282) for the tissue region based on the plurality of EP signals, (ii) estimate a level of orthogonality of the LCV with respect to one or more tangents (355) to the ablation curve (230, 250) within the tissue region, and (iii) identify the presence of a conduction gap (390) in the ablation curve based on the level of orthogonality.

[0086] Example 9 10. The system of claim 8, wherein the processor is configured to identify gaps by comparing the level of orthogonality to a predetermined threshold.

[0087] Example 10 A system (10) described in any one of Examples 8 and 9, wherein the processor (56) is configured to estimate the level of orthogonality by performing a moving average of LCV level orthogonality to the LCV along the ablation line (230, 250).

[0088] Example 11 The method includes receiving a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve (230, 250) within a ventricle (257, 357) of a heart (12) of a patient (23). Local conduction vectors (LCVs) (221, 222) are generated for the region based on the plurality of EP signals. A level of variation is estimated between a set of LCVs (221, 222) along the ablation curve within the tissue region. The presence of a conduction gap (390) in the ablation curve (230, 250) is identified based on the level of variation.

[0089] Example 12 The method includes receiving a plurality of electrophysiological (EP) signals acquired at a tissue region along an ablation curve (230, 250) within a ventricle (257, 357) of a heart (12) of a patient (23). Local conduction vectors (LCVs) (261, 271, 281, 282) are generated for the tissue region based on the plurality of EP signals. A level of orthogonality of the LCVs (261, 271, 281, 282) with respect to one or more tangents (355) to the ablation curve (230, 250) within the tissue region is estimated. Based on the level of orthogonality, the presence of a conduction gap (390) in the ablation curve is identified.

[0090] Although the examples described herein primarily address cardiac diagnostic applications, the methods and systems described herein may also be used in other medical applications.

[0091] 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.

[0092] [Embodiment] (1) an interface configured to receive a plurality of electrophysiological (EP) signals from tissue regions along an ablation curve within a chamber of a patient's heart; 1. A processor, comprising: generating a local conduction vector (LCV) for the region based on the plurality of EP signals; estimating a level of variation between a set of LCVs along the ablation curve within the tissue region; a processor configured to identify the presence of a conduction gap in the ablation curve based on the level of the change. (2) The system of embodiment 1, wherein the processor is configured to identify the gap by comparing the level of change with a predetermined change threshold. (3) The system of embodiment 1, wherein the processor is configured to estimate the level of change by estimating one or both of (i) a change in direction and (ii) a change in magnitude of the LCV. (4) The system of embodiment 1, wherein the processor is configured to estimate the level of variation by generating a representative LCV for each set and estimating the level of variation between the representative LCVs. (5) The system of embodiment 1, wherein the processor is configured to show the ablation curve to a user by interpolating across a set of tags marking the respective locations of the ablation tissue sites and presenting the resulting interpolated curve.

[0093] (6) The system of embodiment 1, wherein the plurality of electrophysiological (EP) signals are one of unipolar and bipolar electrograms acquired using a multi-electrode mapping catheter. (7) A system as described in embodiment 1, wherein the ablation line is an ablation curve that surrounds the opening of a pulmonary vein (PV). (8) an interface configured to receive a plurality of electrophysiological (EP) signals acquired at tissue regions along an ablation curve within a cardiac chamber of the patient's heart; 1. A processor, comprising: generating a local conduction vector (LCV) for the tissue region based on the plurality of EP signals; estimating a level of orthogonality of the LCV to one or more tangents of the ablation curve within the tissue region; a processor configured to identify the presence of a conduction gap in the ablation curve based on the level of orthogonality. (9) The system of embodiment 8, wherein the processor is configured to identify the gap by comparing the level of orthogonality to a predetermined threshold. (10) The system of embodiment 8, wherein the processor is configured to estimate the level of orthogonality by performing a moving average of LCV level orthogonality to the LCV along the ablation line.

[0094] (11) receiving a plurality of electrophysiological (EP) signals from tissue regions along an ablation curve within a cardiac chamber of the patient's heart; generating a local conduction vector (LCV) of the region based on the plurality of EP signals; estimating a level of variation between a set of LCVs along the ablation curve within the tissue region; and identifying the presence of a conduction gap in the ablation curve based on the level of the change. (12) The method of embodiment 11, wherein identifying the gap comprises comparing the level of change by comparing it to a predetermined change threshold. (13) The method of embodiment 11, wherein estimating the level of change comprises estimating one or both of (i) a change in direction and (ii) a change in magnitude of LCV. (14) The method of embodiment 11, wherein estimating the level of variation includes generating a representative LCV for each set and estimating the level of variation between the representative LCVs. (15) The method of embodiment 11, wherein presenting the ablation curve to the user includes interpolating across a set of tags marking the respective locations of the ablation tissue sites and presenting the resulting interpolated curve.

[0095] (16) The method of embodiment 11, wherein the plurality of electrophysiological (EP) signals are one of unipolar and bipolar electrograms acquired using a multi-electrode mapping catheter. (17) The method described in embodiment 11, wherein the ablation line is an ablation curve that surrounds the opening of the pulmonary vein (PV). (18) receiving a plurality of electrophysiological (EP) signals acquired at tissue regions along an ablation curve within a cardiac chamber of a patient's heart; generating a local conduction vector (LCV) of the tissue region based on the plurality of EP signals; estimating a level of orthogonality of the LCV to one or more tangents of the ablation curve within the tissue region; and identifying the presence of a conduction gap in the ablation curve based on the level of orthogonality. (19) The method of embodiment 18, wherein identifying the gap includes comparing the level of orthogonality to a predetermined threshold. (20) The method of embodiment 18, wherein estimating the level of orthogonality includes performing a moving average of LCV level orthogonality for LCV along the ablation line.

Claims

1. an interface configured to receive a plurality of electrophysiological (EP) signals from tissue regions along an ablation curve within a chamber of the patient's heart; 1. A processor, comprising: generating a local conduction vector (LCV) of the region based on the plurality of EP signals; estimating a level of variation between a set of LCVs along the ablation curve within the tissue region; a processor configured to identify the presence of a conduction gap in the ablation curve based on the level of the change.

2. The system of claim 1 , wherein the processor is configured to identify the gap by comparing the level of variation to a predetermined variation threshold.

3. 2. The system of claim 1, wherein the processor is configured to estimate the level of change by estimating one or both of (i) a change in direction and (ii) a change in magnitude of an LCV.

4. The system of claim 1 , wherein the processor is configured to estimate the level of variation by generating a representative LCV for each set and estimating the level of variation between the representative LCVs.

5. 5. The system of claim 1, wherein the processor is configured to present the ablation curve to a user by interpolating across a set of tags marking respective locations of ablation tissue sites and presenting the resulting interpolated curve.

6. 5. The system of claim 1, wherein the plurality of electrophysiological (EP) signals are one of unipolar and bipolar electrograms acquired using a multi-electrode mapping catheter.

7. The system of any one of claims 1 to 4, wherein the ablation line is an ablation curve around the ostium of a pulmonary vein (PV).

8. an interface configured to receive a plurality of electrophysiological (EP) signals acquired at tissue regions along an ablation curve within a chamber of the patient's heart; 1. A processor, comprising: generating a local conduction vector (LCV) for the tissue region based on the plurality of EP signals; estimating a level of orthogonality of the LCV to one or more tangents of the ablation curve within the tissue region; a processor configured to identify the presence of a conduction gap in the ablation curve based on the level of orthogonality.

9. The system of claim 8 , wherein the processor is configured to identify the gaps by comparing the level of orthogonality to a predetermined threshold.

10. 10. The system of claim 8 or 9, wherein the processor is configured to estimate the level of orthogonality by performing a running average of LCV level orthogonality for LCVs along the ablation line.

11. receiving a plurality of electrophysiological (EP) signals from tissue regions along an ablation curve within a chamber of the patient's heart; generating a local conduction vector (LCV) of the region based on the plurality of EP signals; estimating a level of variation between a set of LCVs along the ablation curve within the tissue region; and identifying the presence of a conduction gap in the ablation curve based on the level of the change.

12. The method of claim 11 , wherein identifying the gaps comprises comparing the level of variation by comparing it to a predetermined variation threshold.

13. 12. The method of claim 11, wherein estimating the level of change comprises estimating one or both of (i) a change in direction and (ii) a change in magnitude of LCV.

14. The method of claim 11 , wherein estimating the level of variation comprises generating a representative LCV for each set and estimating the level of variation between the representative LCVs.

15. 15. The method of claim 11, wherein presenting the ablation curve to a user comprises interpolating across a set of tags marking respective locations of ablation tissue sites and presenting the resulting interpolated curve.

16. 15. The method of any one of claims 11 to 14, wherein the plurality of electrophysiological (EP) signals are one of unipolar and bipolar electrograms acquired using a multi-electrode mapping catheter.

17. The method according to any one of claims 11 to 14, wherein the ablation line is an ablation curve around the ostium of a pulmonary vein (PV).

18. receiving a plurality of electrophysiological (EP) signals acquired at tissue regions along an ablation curve within a chamber of the patient's heart; generating a local conduction vector (LCV) of the tissue region based on the plurality of EP signals; estimating a level of orthogonality of the LCV to one or more tangents of the ablation curve within the tissue region; and identifying the presence of a conduction gap in the ablation curve based on the level of orthogonality.

19. 20. The method of claim 18, wherein identifying the gap comprises comparing the level of orthogonality to a predetermined threshold.

20. 20. The method of claim 18 or 19, wherein estimating the level of orthogonality comprises performing a running average of LCV level orthogonality for LCVs along the ablation line.

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