Detection of electrophysiological (EP) conduction gaps in ablation lines

Abstract

The invention discloses a system. The system comprises an interface and a processor. The interface is configured to receive a plurality of electrophysiological (EP) signals from inside a cardiac cavity of a patient's heart along a tissue region of an ablation curve. The processor is configured to: (i) generate a local conduction vector (LCV) for the region based on the plurality of EP signals; (ii) estimating a level of change between a set of LCVs along the ablation curve within the tissue region; and (iii) identifying the presence of a conduction gap in the ablation profile based on the level of change.

Description

Technical Field

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

[0002] The use of mapping catheters to identify arrhythmogenic tissue pathways in cardiac tissue has been proposed previously in the patent literature. For example, International Patent Application Publication WO 2020 / 227469 describes how pulmonary vein isolation (PVI) has become a first-line treatment for symptomatic drug-refractory atrial fibrillation (AF). In the context of a PVI procedure, linear ablation lesions are delivered to achieve PV isolation. Electrophysiological maps from data collected by a high-density grid catheter can be used to identify conduction gaps associated with circumferential pulmonary vein isolation lesions.

[0003] As another example, U.S. Patent Application Publication 2019 / 0125438 describes a method and system for gap detection in an ablation line. Microelectrodes are implemented at the distal end of the catheter to provide local gap detection along the ablation line. A pacing protocol is used to sequentially pass through each of the microelectrode pairs for tissue locations. If living tissue is present, the pacing signal travels through the living tissue to cause the heart to beat. The operator will see a capture signal and know that there is a gap in the ablation line. Thus, pacing and ablation are performed at the same location without switching between instruments and / or catheters.

[0004] US Patent 10,792,087 describes a method for assessing a gap in an ablation lesion based on estimating the temporal relationship between stimulation and sensed activation peaks and the spatial relationship between the stimulation location and the sensing location. In this way, one of a plurality of electrodes of a sensing catheter is identified that is proximal to a gap in the lesion. A map of the body lumen 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,” Volume 14, Pages 741-550, August 2021, Yavin et al. describe how propagation vectors are created from unipolar waveforms acquired in a single beat from adjacent electrodes along and across a catheter array spline. To examine the utility of propagation vectors for detecting conduction block during ablation, a Cavo tricuspid isthmus line was created during coronary sinus pacing with the array positioned lateral to the line. Real-time propagation vectors were found to enhance the ability of standard activation mapping to distinguish complex conduction patterns, including determining conduction block during ablation.

[0006] The present disclosure will be more fully understood through the following detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic illustration of a catheter-based electrophysiological (EP) mapping and ablation system according to one example of the present disclosure;

[0008] Figure 2A and Figure 2B is a rendering of an EP map of a cardiac chamber overlaid with corresponding sets of local conduction vectors (LCVs) showing abrupt changes between sets indicating ablation gaps according to one example of the present disclosure;

[0009] Figure 3A and Figure 3B is a rendering of an EP map of a cardiac chamber according to an example of the present disclosure, showing near antiparallel LCVs indicating adjacent ablations and near orthogonal LCVs indicating gaps in ablations, respectively;

[0010] Figure 4 is a flow chart schematically illustrating a method for identifying an ablation gap by discovering a sudden change in LCV according to an example of the present disclosure; and

[0011] Figure 5 is a flow chart schematically illustrating a method for identifying an ablation gap using the absolute direction of an LCV according to an example of the present disclosure. DETAILED DESCRIPTION

[0012] Overview

[0013] Catheter-based cardiac ablation may not always terminate arrhythmias completely as planned. For example, despite performing pulmonary vein isolation (PVI) by ablating the PV ostium tissue along a curve covering the entire circumference of the PV ostium, atrial fibrillation (AF) may persist. Persistence of arrhythmias may occur due to imperfect ablation, where one or more undesirable gaps remain between otherwise adjacent ablation locations.

[0014] Typically, incomplete ablations require subsequent ablations. Additional ablations are best completed during the same invasive procedure, i.e., immediately after inspection and identification of the gap following the first ablation. However, it is difficult to identify the location of the gap along the ablation curve (the word "ablation line" is also used, meaning the same ablation path along the curve).

[0015] One possible way to obtain an indication of the location of the gap is by mapping EP propagation in cardiac tissue. The propagation is analyzed from a plurality of EP data points acquired by a mapping catheter, each data point comprising an electrogram and the location on the tissue where the electrogram was acquired. Data points are acquired from each electrode on the catheter, and the acquisition is performed automatically without user intervention.

[0016] For example, using these data points, a processor can calculate a local conduction vector (LCV), which by itself can indicate a gap. However, such an indication is often ambiguous and inaccurate. Due to the natural variation in the distribution of EP activation propagation vectors (e.g., LCVs), analysis is difficult and interpretation can be ambiguous.

[0017] Therefore, to identify the exact location of the gap, the physician will need to (a) cross the target area and sometimes (b) apply additional techniques (such as pacing), which is time consuming. When pacing is used, the amplitudes at different timings and / or locations are compared. Searching for gaps based on amplitude results in many true and false positives. In addition, pacing techniques alone cannot identify the exact location of the gap.

[0018] One attempt to improve the analysis is described in U.S. Patent Application 17 / 481,616, filed on 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 collection of data points comprising locations and corresponding velocities of activation waves in a tissue region of a cardiac chamber. Dividing the collection into at least two velocity clusters, each velocity cluster being characterized by a corresponding velocity of the activation wave. Estimating one or more boundary curves between at least two clusters. Indicating the one or more boundary curves to a user as possible block lines for the activation wave.

[0019] Examples of the present disclosure described herein provide a user with a technique to easily detect any gaps in the ablation line in a manner that enables immediate re-ablation.

[0020] In one example, when the catheter is used to scan (eg, tracked by a physician) an ablation line, the processor identifies an ablation gap by detecting a sudden change in the LCV. A sudden change in the direction and / or magnitude of the LCV indicates the presence of an ablation gap therein or thereabouts.

[0021] To estimate how abrupt changes are found in LCV direction and / or magnitude, in some examples, a metric E(a,b) is defined between LCV group a and LCV group b. a For all vectors (LCV group a) mean vector, and V b For all vectors The calculation is for a multi-electrode catheter with n electrodes, where at each LCV calculation frame number k (e.g., at each heartbeat), the 3D vector Calculate for each electrode i, i≤n. Then the distance measure between vectors can be formulated as:

[0022] E(a,b)=(1- <V a ,V b >) / 2

[0023] The value of E(a,b) is in the range [0,1], where 0 indicates a perfect match and 1 indicates the exact opposite direction. If the metric value is greater than a predetermined threshold c (E(a,b)>c, c>0), a gap is indicated to the user. Other metrics are proposed below.

[0024] In other examples, the processor runs 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 can be used with or without pacing.

[0025] In some examples, to find an ablation gap, the processor performs the following steps after ablation and before starting the gap identification process:

[0026] 1. Calculate the ablation line and display it on the EP map. For example, the ablation line can be calculated by interpolating a set of labels marking the corresponding positions of the ablated tissue sites (e.g., points). First, using the GUI, in one example, the line (e.g., path) is displayed as a dashed pattern.

[0027] 2. Guide the physician (eg, using a GUI) to navigate the catheter along the displayed ablation path. In this example, the covered portion of the path (that is analyzed) will become a solid line.

[0028] 3. Detect one or more ablation gaps along the path.

[0029] 4. Mark any detected gaps in the path during navigation on the EP map (eg, with a red line). This step may include overlaying the LCV on the EP map.

[0030] In one example, the gap detection step (3) is based on calculating the aforementioned LCV as the mapping catheter tracks the ablation line. With high probability, if there is no gap along the ablation line, the LCV is expected to be more parallel to the (average) ablation line direction. On the other hand, wherever there is a gap, the LCV is expected to be oriented in a nearly perpendicular direction (i.e., nearly orthogonal) relative to the ablation line at the location of the gap.

[0031] The aforementioned check of the orthogonality level of the LCV can be performed in an automated method by comparing the direction tangent to the defined ablation path with the direction of the average value of the LCV of the segment along the line being checked. All LCV-related calculations are performed in the background and do not have to be displayed. The detected conduction gaps will be visually indicated by a special highlighting method on the map.

[0032] Finally, as a backup method that can be used with catheters that may not include acquisition capabilities sufficient to calculate LCV, the processor can analyze the acquired bipolar EP values ​​along the ablation line.Local extrema of the variation in the bipolar signal can suggest a gap at that location.

[0033] System Description

[0034] Figure 1 is a schematic illustration of a catheter-based electrophysiological (EP) mapping and ablation system 10 according to one example of the present disclosure.

[0035] The system 10 includes a plurality of catheters that are inserted percutaneously through the patient's vascular system into a chamber or vascular structure of the heart 12 by a physician 24. Typically, a delivery sheath catheter is inserted into the left atrium or right atrium near a desired location in the heart 12. Multiple catheters may then be inserted into the delivery sheath catheter to reach the desired location. The multiple catheters may include a catheter dedicated to sensing intracardiac electrogram (IEGM) signals, a catheter dedicated to ablation, and / or a catheter dedicated to both sensing and ablation. An example catheter 14 configured for sensing IEGM is illustrated herein. The physician 24 brings the distal end 28 of the catheter 14 (hereinafter also referred to as the "distal end assembly 28") into contact with the heart wall for sensing a target site in the heart 12. For ablation, the physician 24 would similarly bring the distal end of the ablation catheter to the target site for ablation.

[0036] The catheter 14 is an exemplary catheter that includes one (and preferably multiple) electrodes 26, optionally distributed over a plurality of strips 22 at a distal tip 28 and configured to sense IEGM signals. The catheter 14 may additionally include a position sensor 29 embedded in or near the distal tip 28 for tracking the position and orientation of the distal tip 28. Optionally and preferably, the position sensor 29 is a magnetic-based position sensor that includes three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0037] The magnetic-based position sensor 29 can operate with the positioning pad 25, which includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predetermined working space. The real-time position of the distal tip 28 of the catheter 14 can be tracked based on the magnetic field generated by the positioning pad 25 and sensed by the magnetic-based position sensor 29. The details of the magnetic-based position sensing technology are described in U.S. Patents 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.

[0038] The system 10 includes one or more electrode patches 38 positioned in contact with the skin of the patient 23 to establish a position reference for impedance-based tracking of the positioning pad 25 and the electrodes 26. For impedance-based tracking, current is directed toward the electrodes 26 and sensed at the electrode skin patches 38 so that the position of each electrode can be triangulated via the electrode patches 38. Details of impedance-based position tracking techniques are described in U.S. Patents 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0039] Recorder 11 displays electrograms 21 captured using surface ECG electrodes 18 and intracardiac electrograms (IEGMs) captured using electrodes 26 of catheter 14. Recorder 11 may include pacing capabilities for pacing the cardiac rhythm and / or may be electrically connected to a separate pacemaker.

[0040] The system 10 may include an ablation energy generator 50 adapted to conduct ablation energy to one or more electrodes at the distal end of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radio frequency (RF) energy or pulsed field ablation (PFA) energy (including monopolar or bipolar high voltage DC pulses that may be used to achieve irreversible electroporation (IRE)), or a combination thereof.

[0041] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between catheters, electrophysiology equipment, a power source, and a workstation 55 for controlling the operation of the system 10. The electrophysiology equipment of the system 10 may include, for example, multiple catheters, a positioning pad 25, surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 additionally has processing capabilities for enabling real-time calculation of the position of the catheter and for performing ECG calculations.

[0042] The workstation 55 includes a memory 57, a processor 56 unit with a memory or storage device loaded with appropriate operating software, and user interface capabilities. The workstation 55 can provide multiple functions, optionally including: (1) three-dimensional (3D) modeling of the endocardial anatomy and rendering the model or anatomical map 20 for display on the display device 27; (2) displaying the activation sequence (or other data) compiled from the recorded electrograms 21 on the display device 27 as representative visual markers or images superimposed on the rendered anatomical map 20; (3) displaying the real-time position and orientation of multiple catheters within the heart chamber; and (5) displaying areas of interest on the display device 27, such as where ablation energy has been applied. A commercial product embodying elements of the system 10 can be CARTO TM The 3 system was purchased from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0043] In some examples, processor 56 typically includes a general purpose computer that is programmed in software to perform the functions described herein. The software may be downloaded to the computer in electronic form over a network, for example, or it may alternatively or additionally be provided and / or stored on a non-transitory tangible medium such as magnetic, optical, or electronic storage.

[0044] This particular configuration of system 10 is shown by way of example in order to illustrate certain problems solved by the examples of the present disclosure and to demonstrate the application of these examples in enhancing the performance of such systems. However, the examples of the present disclosure are by no means limited to this particular class of example systems, and the principles described herein may be similarly applied to other classes of medical systems. For example, other types of multi-electrode catheters, such as octaray, may be used. TM catheter or basket catheter.

[0045] Identify ablation gaps along the ablation path by finding sudden changes in LCV

[0046] To identify the ablation gap, the physician can perform EP mapping along the ablation line by, for example, moving the distal end assembly 28 of the mapping catheter 14 from the earliest ablation location. As described above, the entire path will initially be displayed in dashed lines. The processor guides the physician in the direction of moving the mapping catheter along the path, for example, using a GUI. The portion of the path covered by the mapping catheter is continuously displayed in FIG. 3.

[0047] Also seen is an ablation catheter 231 with an ablation electrode 232. This catheter is used in a first ablation to check continuity. The catheter 231 will be used in subsequent ablations to close any conduction gaps found using the disclosed technique.

[0048] Figure 2A and Figure 2B 2 is a rendering of an EP map 225 of a cardiac chamber overlaid with respective sets 221 and 222 of local conduction vectors (LCVs) showing a sudden change between the sets indicating an ablation gap according to one example of the present disclosure. The sudden change in direction occurs at a tissue site along an ablation line 230.

[0049] To achieve this, a system such as system 10 includes an interface configured to receive a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve within a cardiac chamber of a patient's heart. A processor of system 10 is configured to: (i) indicate to a user the ablation curve along which the plurality of EP signals were acquired; (ii) generate a local conduction vector (LCV) for the region based on the plurality of EP signals; (iii) estimate a level of variation 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 variation. The processor is configured to estimate the level of variation by comparing the level of variation to a predetermined variation threshold.

[0050] The processor is configured to estimate the level of variation by generating a representative LCV for each set, and to estimate the level of variation between the representative LCVs. The estimation of the variation may involve using one of the following metrics:

[0051] Metrics used to measure changes in LCV

[0052] With n electrodes, where at each LCV calculation frame number k (e.g., at each heartbeat), the 3D vector Calculate for each electrode i, i≤n. Vector are normalized and have length 1.

[0053] Several metrics may be considered to identify the overall vector change between frames.

[0054] There are two frames a and b (with vectors and ). All vectors discussed in this article are unit-length vectors, and<x,y> Represents the inner product between x and y.

[0055] Let V a For all vectors The average vector, and V b For all vectors The average vector of . Then a distance measure between vectors can be formulated as:

[0056] E(a,b)=(1- <V a ,V b >) / 2

[0057] Another metric that can be applied is by using L on the change in angle between corresponding vectors across the frame 2 distance metric, but this metric is slightly more computationally expensive.

[0058]

[0059] Where: w i is the vector v i The weighting allows to take into account more information / parameters of interest to the formula, such as: voltage, position in the conduit grid. It is important to have positive normalized weights such that:

[0060]

[0061] You can also use L 2 Other distance metrics besides L 1 ,L n ,L ∞ .

[0062] For stability purposes, the above calculations may not be performed between two consecutive frames, but between two averages of several frames. For example, each vector is averaged for every three consecutive frames and compared (the above calculation metric is performed between two subsequent averages (involving six frames)).

[0063] Identifying ablation gaps along the ablation path by estimating the absolute orientation of the LCV

[0064] Figure 3A and Figure 3B are renderings of EP maps 227 and 327 of cardiac chambers 257 and 357, respectively, according to an example of the present disclosure. Figure 3A Nearly antiparallel LCVs indicating adjacent ablations are shown in (261,271) and in Figure 3B Nearly orthogonal LCVs indicating gaps in ablation are shown in (281, 282).

[0065] exist Figure 3A middle, Figure 1 The distal tip assembly 28 of the catheter 14 is advanced distally along the ablation line 250 drawn by the processor. As shown, the portion 252 of the line 250 that has been inspected using the electrode of the distal tip assembly is marked as a solid line, while the remaining portion 253 is still shown as a dashed line. Figure 3A In the example shown, the LCVs of the vector sets (261, 271) on either side of the portion 252 of the ablation line 250 are oriented largely antiparallel to each other. Parallel or antiparallel EP propagation vectors on either side of the ablation line indicate with high probability that the ablation there is complete, e.g., without a conduction gap.

[0066] exist Figure 3B In Figure 1 The distal tip assembly 28 of the catheter 14 is pulled proximally along the ablation line 350. As shown, the portion 352 of the line 350 that has been inspected using the electrode of the distal tip assembly is marked as a solid line, while the remaining portion 353 remains a dashed line. Figure 3B In the example shown, some of the vectors of the set of vectors (271, 281) on either side of the portion 252 of the ablation line 250 are oriented substantially perpendicular to the ablation line therein. This is illustrated at location 349, where the angle 370 between the tangent line 355 and the LCV direction 360 is sufficiently close to 90 degrees to make location 349 part of a gap. The presence of EP propagation vectors that are substantially perpendicular to the ablation line indicates with high probability that the ablation there is incomplete, e.g., one or more conduction gaps are present therein.

[0067] The location of the conduction gap is displayed by causing a portion 390 of the ablation line 350 to be highlighted by the processor. By way of example, the highlighting may change the color of the line segment 390 (eg, from black to red).

[0068] Method for identifying ablation gaps along an ablation path

[0069] Figure 4 1 is a flowchart schematically illustrating a method for identifying ablation gaps by finding sudden changes in LCV according to an example of the present disclosure. According to the proposed example, the algorithm performs the following process, which begins at the EP data acquisition step 402 using the system 10 and Figure 1 The flat catheter assembly 28 collects EP data points along the ablation line inside the heart chamber (such as heart chamber 225). To this end, the processor 56 displays the ablation line 230 overlaid on the EP map, as shown in Figure 2, and uses a graphical tool such as that described in conjunction with Figure 3 to guide the physician in real time where to move the mapping catheter in order to collect relevant EP data points.

[0070] In an EP data analysis step 404 , processor 56 runs a program to generate a local conduction vector (LCV), such as shown in FIG. 2 .

[0071] At 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.

[0072] At orthogonality check 408, the processor compares the found orthogonality level to a predetermined threshold (e.g., to a minimum predetermined angle). The orthogonality is measured compared to the ablation line direction at the location of the catheter. In this case, a metric is used to measure whether the vectors are generally orthogonal. The above metric can also be used as V a The vector (LCV) of the curve is V b The tangent vector (direction) used between .

[0073] In this case, the algorithm may consider how orthogonal most vectors are to the path direction, as an alternative to using a metric. This may be checked statistically (eg, by checking a moving average of orthogonality) per LCV or per local set of LCVs.

[0074] In the event that the orthogonality level is found to be above the threshold, processor 56 indicates the presence of a conduction gap in the ablation curve at a gap indication step 410 .

[0075] In either case, the process returns to step 402 as long as the mapping catheter is moving along the ablation line.

[0076] Figure 51 is a flow chart schematically illustrating a method for identifying an ablation gap using the absolute direction of an LCV according to an example of the present disclosure. According to the proposed example, the algorithm performs the following process, which begins at the EP data acquisition step 502 using the system 10 and Figure 1 The flat catheter assembly 28 collects EP data points along the ablation line inside the heart chamber (such as the heart chamber 357). To this end, the processor 56 displays the ablation line overlaid on the EP map, as shown in Figures 2 and 3, and uses a graphical tool such as that described in conjunction with Figures 2 and 3 to guide the physician in real time where to move the mapping catheter in order to collect relevant EP data points.

[0077] In an EP data analysis step 504 , processor 56 runs a program to generate local conduction vectors (LCVs), such as those shown in FIGS. 2 and 3 .

[0078] At the next LCV analysis step 506, the processor estimates the level of orthogonality of the LCV relative to one or more tangents to the ablation curve.

[0079] At orthogonality check 508, the processor compares the found orthogonality level to a predetermined threshold (eg, to a minimum predetermined angle).The check may be done statistically (eg, by checking a moving average of orthogonality), per LCV or per local set of LCVs.

[0080] In the event that the orthogonality level is found to be above the threshold, processor 56 indicates the presence of a conduction gap in the ablation curve at a gap indication step 510 .

[0081] In either case, the process returns to step 502 as long as the mapping catheter is moving along the ablation line.

[0082] Figure 4 and Figure 5 The flowchart shown is selected purely for conceptual clarity. The inventive example may also include additional steps of the algorithm, such as pre-selecting the input EGM based on an indication from the contact force sensor of the degree of physical contact of the electrode with the diagnosed tissue. This step and other possible steps are intentionally omitted from the disclosure herein in order to provide a more simplified flowchart.

[0083] Example

[0084] Example 1

[0085] A 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 cardiac chamber (257, 357) of a heart (12) of a patient (23). The processor is configured to: (i) generate a local conduction vector (LCV) (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.

[0086] Example 2

[0087] The system (10) of embodiment 1, wherein the processor (56) is configured to identify the gap (390) by comparing the level of change to a predetermined change threshold.

[0088] Example 3

[0089] A system (10) according to any one of embodiments 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).

[0090] Example 4

[0091] A system (10) according to any one of embodiments 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.

[0092] Example 5

[0093] A system (10) according to any one of embodiments 1 to 4, wherein the processor (56) is configured to indicate the ablation curve (230, 250) to a user by interpolating on a set of labels marking corresponding positions of ablation tissue sites and presenting the resulting interpolated curve.

[0094] Example 6

[0095] A system (10) according to any one of embodiments 1 to 5, wherein the plurality of electrophysiological (EP) signals are one of unipolar electrograms and bipolar electrograms acquired using a multi-electrode mapping catheter (14).

[0096] Example 7

[0097] A system (10) according to any one of embodiments 1 to 6, wherein the ablation line (230, 250) is an ablation curve on the circumference of the ostium of the pulmonary vein (PV).

[0098] Example 8

[0099] A system (10) includes an interface (30) and a processor (56). The interface (30) is configured to receive a plurality of electrophysiological (EP) signals acquired in a tissue region along an ablation curve (230, 250) within a cardiac chamber (257, 357) of a heart (12) of a patient (23). The processor (56) is configured to: (i) generate a local conduction vector (LCV) (261, 271, 281, 282) for the tissue region based on the plurality of EP signals; (ii) estimate a level of orthogonality of the LCV relative to one or more tangents (355) of 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 orthogonality level.

[0100] Example 9

[0101] The system (10) of embodiment 8, wherein the processor (56) is configured to identify the gap (390) by comparing the orthogonality level to a predetermined threshold.

[0102] Example 10

[0103] A system (10) according to any of embodiments 8 and 9, wherein the processor (56) is configured to estimate the orthogonality level by running a moving average of the LCV level orthogonality for the LCV along the ablation line (230, 250).

[0104] Embodiment 11

[0105] A method comprising: receiving a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve (230, 250) within a cardiac chamber (257, 357) of a heart (12) of a patient (23). Generating a local conduction vector (LCV) (221, 222) for the region based on the plurality of EP signals. Estimating a level of variation between a set of LCVs (221, 222) along the ablation curve within the tissue region. Based on the level of variation, identifying the presence of a conduction gap (390) in the ablation curve (230, 250).

[0106] Example 12

[0107] A method comprising: receiving a plurality of electrophysiological (EP) signals acquired in a tissue region along an ablation curve (230, 250) within a cardiac chamber (257, 357) of a heart (12) of a patient (23). Generating a local conduction vector (LCV) (261, 271, 281, 282) for the tissue region based on the plurality of EP signals. Estimating a level of orthogonality of the LCV (261, 271, 281, 282) relative to one or more tangents (355) of the ablation curve (230, 250) within the tissue region. Based on the level of orthogonality, identifying the presence of a conduction gap (390) in the ablation curve.

[0108] Although the embodiments described herein are primarily directed to cardiac diagnostic applications, the methods and systems described herein can also be used in other medical applications.

[0109] It should be understood that the above embodiments are cited by way of example, and the present disclosure is not limited to what is specifically shown and described above. On the contrary, the scope of the present disclosure includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which should be expected by those skilled in the art when reading the above description, and which are not disclosed in the prior art.

Claims

1. A system, comprising: an interface configured to receive a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve within a chamber of a heart of a patient; and A processor, the processor being configured to: generating a local conduction vector (LCV) for the region based on the plurality of EP signals; estimating a level of variation between sets of LCVs along the ablation curve within the tissue region; and Based on the level of change, the presence of a conduction gap in the ablation curve is identified.

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

3. The system according to 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 the LCV.

4. The system according to 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. The system according to claim 1, wherein: The processor is configured to indicate the ablation curve to a user by interpolating over a set of labels marking corresponding locations of ablated tissue sites and presenting the resulting interpolated curve.

6. The system according to claim 1, wherein: The plurality of electrophysiological (EP) signals is one of a unipolar electrogram and a bipolar electrogram acquired using a multi-electrode mapping catheter.

7. The system according to claim 1, wherein: The ablation line is an ablation curve on the circumference of the ostium of the pulmonary vein (PV).

8. A system, comprising: an interface configured to receive a plurality of electrophysiological (EP) signals acquired in a tissue region along an ablation curve within a cardiac chamber of a heart of a patient; and A processor, the processor being configured to: 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 relative to one or more tangents to the ablation curve within the tissue region; and Based on the level of orthogonality, the presence of a conduction gap in the ablation curve is identified.

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

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

11. A method comprising: receiving a plurality of electrophysiological (EP) signals from a tissue region along an ablation curve within a chamber of a heart of the patient; generating a local conduction vector (LCV) for the region based on the plurality of EP signals; estimating a level of variation between sets of LCVs along the ablation curve within the tissue region; and Based on the level of change, the presence of a conduction gap in the ablation curve is identified.

12. The method according to claim 11, wherein: Identifying the gap includes comparing the level of change by comparing it to a predetermined change threshold.

13. The method according to claim 11, wherein: Estimating the level of change includes estimating one or both of (i) a change in direction and (ii) a change in magnitude of the LCV.

14. The method according to claim 11, wherein: Estimating the variation level includes generating a representative LCV for each set and estimating the variation level between the representative LCVs.

15. The method according to claim 11, wherein: Indicating the ablation curve to the user includes interpolating over a set of labels marking corresponding locations of ablated tissue sites and presenting a resulting interpolated curve.

16. The method according to claim 11, wherein: The plurality of electrophysiological (EP) signals is one of a unipolar electrogram and a bipolar electrogram acquired using a multi-electrode mapping catheter.

17. The method according to claim 11, wherein: The ablation line is an ablation curve on the circumference of the ostium of the pulmonary vein (PV).

18. A method comprising: receiving a plurality of electrophysiological (EP) signals acquired in a tissue region along an ablation curve within a cardiac chamber of a patient's heart; 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 relative to one or more tangents to the ablation curve within the tissue region; and Based on the level of orthogonality, the presence of a conduction gap in the ablation curve is identified.

19. The method according to claim 18, wherein: Identifying the gap includes comparing the orthogonality level to a predetermined threshold.

20. The method according to claim 18, wherein: Estimating the orthogonality level includes running a moving average of the LCV level orthogonality for the LCVs along the ablation line.

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