Solving the dual potential problem

Abstract

To provide a method for electrophysiological assessment for analyzing results of a cardiac invasive procedure.SOLUTION: The method comprises: acquiring electrical signals from locations of a region of ablated tissue in a heart chamber; deriving from the signals respective annotations, which are indicative of times within a heart cycle at which a conduction wave traversed the locations; identifying a first location, at a first distance from the region, where the electrical signals include a double-potential signal, having first and second annotations at different times within the heart cycle at the first location; identifying, in proximity to the first location, a second location, at a second distance from the region greater than the first distance, where the electrical signals have a third annotation at the second location; and selecting one of the first and second annotations that is the closest to the third annotation as a valid annotation for the first location, and displaying the valid annotation on an electroanatomical map of the heart.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates generally to invasive medical procedures, and more particularly to analyzing the results of cardiac invasive procedures. [Background technology]

[0002] Invasive cardiac procedures typically involve acquiring intracardiac (IC) electrocardiograph (ECG) signals and analyzing the signals. Analysis of IC ECG signals is well known in the art.

[0003] For example, U.S. Patent No. 10,314,542 (Bar-Tal et al.) describes a system for determining a region of interest for cardiac ablation using segmentation. The method includes detecting electrocardiogram (ECG) signals via sensors. Each ECG signal is detected via one of the sensors and indicates electrical activity of the heart. The system also includes determining a region of interest for cardiac ablation according to the segmentation.

[0004] U.S. Patent Application Publication No. 2018 / 0235495 (Rubenstein) describes a cardiac mapping catheter and method of using the catheter that can detect the presence, direction, and / or origin of depolarization wavefronts associated with cardiac arrhythmias.

[0005] No. 10,335,052 (El Haddad) describes a device for analyzing electrophysiological data, which uses processing means adapted to perform a stepwise analysis of the electrophysiological data to generate a signal indicative of the presence of a pulmonary vein potential component.

[0006] US Patent No. 6,236,883 (Ciaccio et al.) describes a method that includes identifying and localizing reentrant circuits from electrogram features using a feature detection and localization (FDL) algorithm.

[0007] U.S. Patent Application Publication No. 2017 / 0079539 (Chauhan et al.) describes a system for locating focal sources of electrophysiological activity within an organ. The system may also be used to guide catheter ablation of the organ. Summary of the Invention [Means for solving the problem]

[0008] An exemplary embodiment of the present invention provides a method for electrophysiological assessment, the method comprising: acquiring electrical signals from myocardial tissue at a plurality of locations within a chamber of the heart proximate the region of ablated tissue; deriving respective annotations from the electrical signals, the annotations indicating times within a cardiac cycle at which conducted waves in the myocardial tissue traversed the locations; identifying a first location at a first distance from the region of ablated tissue, wherein the electrical signal includes a dual potential signal at the first location having a first annotation and a second annotation at different respective times within the cardiac cycle; identifying a second location proximate the first location and at a second distance from the region of ablated tissue that is greater than the first distance, the electrical signal having a third annotation at the second location; selecting one of the first annotation and the second annotation that is closest to the third annotation as a valid annotation for the first location; and displaying the valid annotations on an electroanatomical map of the heart.

[0009] In the exemplary embodiment disclosed, the electrical signal at the second location comprises a single potential signal or a dual potential signal.

[0010] In another disclosed exemplary embodiment, the heart chamber includes an atrium of the heart.

[0011] In yet another disclosed exemplary embodiment, the heart chamber includes a ventricle of the heart.

[0012] In further disclosed exemplary embodiments, the region of ablated tissue comprises one or more discrete points. Alternatively or additionally, the region of ablated tissue comprises a line segment.

[0013] In an alternative exemplary embodiment, displaying the valid annotation on the electroanatomical map includes deriving a local activation time (LAT) for the first location from the valid annotation and incorporating the LAT into the map.

[0014] In a further alternative exemplary embodiment, the first location is within a preset threshold distance from the region of tissue to be ablated. The preset threshold distance may be 10 mm.

[0015] There is further provided, in accordance with an exemplary embodiment of the present invention, an apparatus for electrophysiological assessment, the apparatus comprising: a display configured to present an electroanatomical map of the heart; and a probe configured to acquire electrical signals from myocardial tissue at a plurality of locations within a chamber of the heart near the region of ablated tissue; 1. A processor, comprising: deriving respective annotations from the electrical signals, the annotations indicating times within a cardiac cycle at which conducted waves in the myocardial tissue traversed the locations; identifying a first location at a first distance from the region of ablated tissue, wherein the electrical signal includes a dual potential signal having a first annotation and a second annotation at the first location at different respective times within the cardiac cycle; identifying a second location proximate the first location and at a second distance from the region of ablated tissue that is greater than the first distance, the electrical signal having a third annotation at the second location; selecting one of the first annotation and the second annotation that is closest to the third annotation as a valid annotation for the first location; and displaying the valid annotations on an electroanatomical map of the heart. [Brief explanation of the drawings]

[0016] The present invention will be more fully understood from the following detailed description of illustrative embodiments thereof, taken in conjunction with the drawings in which: [Figure 1] 1 is a schematic diagram of a dual potential analysis system according to an exemplary embodiment of the present invention; [Figure 2] 1 is a schematic diagram of the distal end of a catheter according to an exemplary embodiment of the invention for use in the system. [Figure 3] FIG. 2 illustrates an example of an intracardiac electrocardiogram signal according to an exemplary embodiment of the present invention. [Figure 4A] 1 is a schematic illustration of an electroanatomical map of a section of tissue of a chamber of a heart, in accordance with an exemplary embodiment of the present invention; [Figure 4B] 1 is a schematic illustration of a map of a section of tissue of a chamber of a heart after ablation has been performed, in accordance with an exemplary embodiment of the present invention; [Figure 5] 4 is a flowchart of the steps of an algorithm executed by a processor of the system, in accordance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Overview When a section of cardiac tissue is ablated, typically along an ablation line, there is a high probability of double potentials occurring at locations near the ablation, i.e., instead of a signal with one annotation, the signal has two annotations, and although only one of the annotations represents the time at which the conducted wave crosses a given location, the system processor may select the incorrect one.

[0018] In an exemplary embodiment of the invention, the system processor knows the location of the ablation region. For points close to the ablation region where dual potentials occur, the processor uses this knowledge to select which of the dual potential annotations is assumed to be correct. The annotation selected is the one closer in time to the annotation of an adjacent point that is farther away from the ablation region.

[0019] Thus, in an exemplary embodiment of the invention, electrical signals are obtained from myocardial tissue at multiple locations within a chamber of the heart near a region of ablated tissue, and respective annotations are derived from the electrical signals, the annotations indicating the time within the cardiac cycle at which a conducted wave within the myocardial tissue traversed the location.

[0020] A first location is identified at a first distance from the region of ablated tissue, the first location being where the electrical signal includes a dual potential signal having a first annotation and a second annotation at different respective times within the cardiac cycle.

[0021] A second location is identified that is proximate to the first location and at a second distance from the region of ablated tissue that is greater than the first distance, the second location having an electrical signal with a third annotation.

[0022] The one of the first and second annotations that is closest to the third annotation is selected as a valid annotation for the first location. The valid annotation is then displayed on the electroanatomical map of the heart.

[0023] System Description In the following description, like elements in the drawings will be identified by like numerals, and where necessary, the like elements will be distinguished by adding a letter to the identifying numeral.

[0024] Reference is now made to Figure 1, which is a schematic illustration of a dual potential analysis system 20, and Figure 2, which is a schematic illustration of the distal end of a catheter used in the system, in accordance with an embodiment of the present invention. For purposes of brevity and clarity, the following description will assume that a medical procedure is being performed by an operator 22 of the system 20, herein assumed to be a medical professional, who inserts a catheter 24 into the left or right femoral vein of a patient 28, unless otherwise noted. The procedure is assumed to involve an investigation of a chamber of the patient's heart 34, and in this procedure, a catheter, also referred to herein as a probe 32, is first inserted into the patient until the distal end 32 of the catheter reaches a chamber of the heart. The chamber typically includes an atrium or ventricle of the heart.

[0025] System 20 may be controlled by a system processor 40 including a processing unit (PU) 42 in communication with electromagnetic tracking module 36 and / or current tracking module 37. PU 42 also communicates with ablation module 39 and ECG (electrocardiogram) module 43. The module functions are described in more detail below. PU 42 also communicates with memory 44. Processor 40 is typically mounted on a console 46, which typically includes operation controls 38, including a positioning device such as a mouse or trackball, through which operator 22 interacts with the processor. The processor operates system 20 using software stored in memory 44. Results of operations performed by processor 40 are presented to the operator on display 48. The results, typically in the form of an electroanatomical map 49 of heart 34, enable the operator to form an electrophysiological assessment of the heart. The software may be downloaded to the processor 40 in electronic form, for example over a network, or it may alternatively or additionally be provided and / or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory.

[0026] To track the path of probe 32 within mapping region 30, which includes heart 34, exemplary embodiments of the present invention use at least one of a current-based tracking system 21 and an electromagnetic-based tracking system 23. Both systems are described below.

[0027] Tracking system 21 includes an amperometric tracking system similar to that described in U.S. Pat. No. 8,456,182 (Bar-Tal et al.), the disclosure of which is incorporated herein by reference. The Carto® system, manufactured by Biosense-Webster (33 Technology Drive, Irvine, CA 92618 USA), also uses an amperometric tracking system. The amperometric tracking system is controlled by current tracking module 37. Probe 32 has one or more probe electrodes 50, assumed herein to include, by way of example, electrode 50A and electrode 50B, and in tracking system 21, module 37 injects current into the tracked electrode or electrodes 50. The current is received by a plurality of generally similar patch electrodes 77, also referred to herein as patches, placed on the skin of patient 28 and returned to the module.

[0028] Conductive cables for the patch electrodes 77 and other skin electrodes described herein are present for each electrode, but for clarity, cables are shown in the figures for only some of the electrodes. The current between a given probe electrode 50 and a skin patch 77 varies according to the electrode's location due, among other things, to the electrode's different distance from the patch, generating different impedances between a given probe electrode and different patches. Module 37 may be configured to measure the different currents received by different patches 77 on respective channels connected to the patches and generate an indication of the location of a given probe electrode from the different currents.

[0029] The electromagnetic tracking system 23 is similar to that described in U.S. Pat. No. 6,690,963 (Ben-Haim et al.), the disclosures of which are incorporated herein by reference, and that used in the Carto™ system manufactured by Biosense-Webster. The electromagnetic tracking system is controlled by an electromagnetic tracking module 36. The electromagnetic tracking system includes multiple magnetic field generators, envisioned herein as including three sets of generators 66, each set with three orthogonal coils, for a total of nine coils. The generators 66 are placed at known positions directly beneath the patient 28, which positions define the generator's frame of reference. The module 36 controls, among other things, the amplitude and frequency of the alternating magnetic fields generated by the generators.

[0030] The alternating magnetic field interacts with a coil 51 located within the probe 32, thereby generating an alternating electrode potential within the coil, which is received as a signal by the tracking module 36. The module, together with the processing unit 42, analyzes the received signal and is able to determine from the analysis the position, i.e., location and orientation, of the probe coil within a defined frame of reference.

[0031] Typically, tracking by one or both systems may be visually represented on display 48, for example, by incorporating icons representing the probes into a map 49 of heart 34 and by the paths taken by the icons. For clarity, the following description assumes that only electromagnetic tracking system 23 is used, but the description may be adapted mutatis mutandis if both system 23 and system 21 are used, or if only system 21 is used.

[0032] Ablation module 39 includes a radio frequency (RF) generator that delivers RF power to a region of heart 34 selected by operator 22, thereby ablating the region. Operator 22 selects the region by positioning an ablation probe comprising an ablation electrode in the region. In some embodiments, probe 32 and one of electrodes 50, such as electrode 50B, may be used as the ablation probe and the ablation electrode. Alternatively, separate ablation probe and ablation electrode may be used for the ablation provided by module 39.

[0033] The ECG module 43 receives intracardiac (IC) ECG signals acquired by the electrodes 50 when the electrodes are in contact with myocardial tissue of the chambers of the heart 34. The ECG module, together with the PU 42, analyzes the signals to, among other things, find the local activation time (LAT) of the signal, as described below. Typically, the module plots its measurements against a reference ECG signal, such as one that might be provided by electrodes positioned in the coronary sinuses of the heart 34.

[0034] FIG. 3 shows an example of IC ECG signals according to an embodiment of the present invention. Signals 100 and 102 are acquired by electrodes 50 in contact with respective locations of myocardial tissue in a chamber of the heart, assumed herein as an example to be the atrium. The signals are voltage-versus-time signals; for simplicity, the signal axes are not shown in FIG. 3 . PU 42 and module 43 analyze each signal to determine one or more annotations for each of the signals. The annotation for a given location indicates the time in the beating heart cycle at which a conducted wave in the heart crosses that location, i.e., LAT, and is assumed herein to include an ordered pair of signals, i.e., the signal's voltage V and time t.

[0035] As is known in the art, the annotation for a given ECG signal may be set in different ways, for example, the annotation for the ventricle may be set with the steepest negative slope, i.e.

[0036]

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[0037]

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[0038] In the following description, unless otherwise stated, it is assumed that the IC ECG signal is acquired from the atrium of the heart, and the annotation of the acquired signal is assumed to be at the time of the maximum of the P-wave signal.

[0039]

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[0040] Signal 100 illustrates a signal with a single annotation 110 at the peak of the P wave, also referred to as a single potential signal. Signals with a single annotation, such as signal 100, are typically produced by heart 34 when it is beating in sinus rhythm.

[0041] Signal 102 illustrates a signal with two annotations 114, 118, where the P wave has two peaks. Such a signal is called a double potential signal. While a heart beating in sinus rhythm may produce a double potential signal, the presence of double potentials may indicate, for example, arrhythmia, scar tissue, or ablated tissue.

[0042] As described below, signals such as those illustrated in FIG. 3 are used to generate an electroanatomical map 49 of the heart 34.

[0043] 4A is a schematic illustration of an electroanatomical map 150 of an atrial section of heart 34, in accordance with an embodiment of the present invention. Map 150 was generated prior to ablation of myocardial tissue of heart 34, and the map illustrates a portion of electroanatomical map 49.

[0044] To generate map 49, a three-dimensional (3D) map of the heart chamber may first be generated by moving distal end 32 within the heart chamber and tracking and recording the position of the distal end using one of the tracking systems mentioned above. The recorded positions include a point cloud of positions within and on the surface of the heart chamber, and processor 40 may then analyze the point cloud by methods well known in the art to generate a 3D envelope surrounding the point cloud. The envelope corresponds to the tissue surface of the atrium.

[0045] Once the 3D map is generated, the atrial surface can be characterized by acquiring and recording IC ECG signals from locations on the atrial surface. Electrodes 50 at distal end 32 can be used to acquire signals while recording the location of the distal end, and hence the location of the electrodes. Characterization can be as shown above for the signals in FIG. 3, including processor 40 calculating an annotation of the signal. From the annotation, the processor can initially assign a LAT to the location where the IC ECG signal is acquired, by methods well known in the art.

[0046] For single potential signals, the LAT typically corresponds to the time of the single potential annotation, i.e., the time of the P-wave maximum. Thus, for signal 100, the LAT is at the time of annotation 110. For dual potential signals, except as further explained below, the LAT is assumed to correspond to the time of the annotation with the maximum voltage. (If the annotation is

[0047]

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[0048]

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[0049] Thus, for signal 102, if annotation 114 has a greater voltage than annotation 118, then the LAT is at the time of annotation 114. In displays of annotated signals, as further discussed below, typically only the annotation selected for the LAT is superimposed on the signal. In FIG. 3, annotation 114 is depicted as a filled circle to indicate that it is the annotation selected for the LAT of signal 102. Similarly, annotation 110 is depicted as a filled circle to indicate that it is the annotation selected for the LAT of signal 100.

[0050] Once the LAT value for a particular location is determined, a processor can overlay the measurements onto a 3D map of the heart chambers, typically interpolating between values, to generate an electroanatomical map. Different LAT values are typically depicted in maps 150 and 49 as different colors, and are shown schematically in FIG. 4A as different types of shading 152L, 154L, and 156L for atrial regions 152, 154, and 156, respectively. As shown schematically in FIG. 4A, the LAT value, typically in ms, may be shown on display 48 as a legend for the map.

[0051] The operator 22 can evaluate the map 150 and from the evaluation can decide to ablate a region of myocardial tissue to eliminate a problem, such as an arrhythmia, typically occurring in the heart 34. To perform the ablation, the operator moves the distal end 32 so that the electrode 50 is at a selected location in the tissue. The movement can be tracked by one of the tracking systems mentioned above, and the selected location can be recorded by the processor 40 when it is reached.

[0052] In addition to recording the selected location, once the operator has performed ablation at that location, the location may be marked on map 49, as described below with reference to FIG. 4B.

[0053] 4B is a schematic illustration of map 160 of the atrial section of heart 34 after ablation has been performed, in accordance with an embodiment of the present invention. Except as described below, map 160 is substantially similar to map 150, such that the locations of regions 152, 154, and 156 are the same in the two maps. Map 160 also includes marked locations 164 on the atrium that indicate where the ablation has been performed. By way of example, the ablation is assumed to be on a line, although it will be understood that virtually any type of shape, including point regions, may be marked on the atrial map as locations 164.

[0054] After the ablation illustrated in map 160, operator 22 may reacquire IC ECG signals from the tissue to assess the effectiveness of the ablation and update the map. The flowchart in Figure 5 below illustrates the steps of the algorithm executed by processor 40 when the operator reacquires the signals.

[0055] 5 is a flowchart of algorithmic steps executed by processor 40, according to an embodiment of the present invention. In a first step 180, operator 22 evaluates an electroanatomical map of the atria of heart 34, assumed herein to correspond to map 49, and as a result of the evaluation, the operator decides to ablate a region of myocardial tissue in the atria. The ablated region may include one or more discrete points of tissue. Alternatively, the ablated region may be in the form of a line segment similar to that illustrated in map 160 of FIG. 4B.

[0056] In a recording step 184, processor 40 records the location of the performed ablation and indicates the location on map 49 that is displayed to the operator. Indicating the location typically involves incorporating one or more icons into map 49.

[0057] In a signal acquisition step 188, the operator moves the probe 32 to positions on the surface of the atrium, and the electrodes 50 acquire a respective ECG signal at each of the positions. The processor 40 stores the signals with module 43. For each acquired ECG signal, the processor analyzes the signal to determine one or more annotations within the signal. The processor stores the annotations and the locations at which the signals providing the annotations were acquired.

[0058] Unless otherwise noted, processor 40 repeats the following steps of the flowchart, as indicated by arrow 186, to analyze the obtained results. The repeated steps of the flowchart are indicated in Figure 5 by being enclosed in a dashed rectangle 190. In each iteration, the processor separately analyzes each obtained ECG signal, as well as the annotations and positions of the stored ECG signals, as described above.

[0059] In a first decision step 192, processor 40 checks whether the signal is a single potential signal, i.e., whether the signal has a single annotation. If decision 192 returns a yes, then in an assignment step 194, the processor assigns the time of the annotation to be the LAT for that location. If decision 192 returns a no, the flowchart continues to a dual potential step 196.

[0060] In step 196, processor 40 determines that the signal being analyzed is a dual potential signal.

[0061] In a second determination step 200, the processor 40 calculates the distance of each of the signal locations from the ablated region and evaluates whether the location is close to the region. That is, the processor calculates the distance of the signal locations from all the ablated regions and determines whether any of the distances are within a preset threshold distance. In one embodiment, the threshold distance is set to 10 mm.

[0062] If step 200 returns a negative result, i.e., the signal location is not within a preset threshold distance and is therefore far from the ablated region, then in a further evaluation step 202 the processor assumes that the LAT for the location of the dual potential corresponds to the annotation of the maximum potential.

[0063] If step 200 returns a positive result, i.e., the signal location is within a preset threshold distance, then the location is close to at least one of the ablated regions. In this case, in annotation assignment step 204, the processor assumes that the LAT, i.e., valid annotation, for the location is the annotation that is closest to the annotation for an adjacent location that is farther from the ablated region. It will be understood that the signal at the adjacent location can be a single-potential signal or a dual-potential signal.

[0064] Once processor 40 has completed analysis of all ECG signals acquired in step 188, i.e., once the processor has completed the above-described iterative steps, the processor updates map 49 in an update step 208. In the update step, the processor incorporates the valid annotations of steps 194, 202, and 204 into map 49 by displaying the LAT values of the annotations within the map. By reviewing the updated map, operator 22 can use the results generated above to assess the effectiveness of the ablation performed in initial step 180.

[0065] The above explanation assumes that the annotation of the P wave is at the time of the maximum P wave.

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[0067] For clarity, the above description assumes that the dual potential signals are obtained from the atria of the heart and analyzed according to the algorithm of Figure 5. The above description also applies mutatis mutandis to dual potential signals generated in the ventricles of the heart. Accordingly, embodiments of the present invention include analysis of dual potential signals generated in any chamber of the heart.

[0068] It will be understood that the above-described embodiments are given by way of example, and that the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features as 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.

[0069] [Embodiment] (1) A method for electrophysiological assessment, comprising: acquiring electrical signals from myocardial tissue at a plurality of locations within a chamber of the heart proximate the region of ablated tissue; deriving respective annotations from the electrical signals, the annotations indicating times within the cardiac cycle at which conducted waves in the myocardial tissue traversed the locations; identifying a first location at a first distance from the region of ablated tissue, wherein the electrical signal includes a dual potential signal at the first location having a first annotation and a second annotation at different respective times within the cardiac cycle; identifying a second location proximate the first location and at a second distance from the region of ablated tissue greater than the first distance, the electrical signal having a third annotation at the second location; selecting one of the first annotation and the second annotation that is closest to the third annotation as a valid annotation for the first location; and displaying the valid annotations on the electroanatomical map of the heart. (2) A method for electrophysiological evaluation as described in embodiment 1, wherein the electrical signal at the second location includes a single potential signal. (3) A method for electrophysiological evaluation as described in embodiment 1, wherein the electrical signal at the second location includes a dual potential signal. (4) The method of embodiment 1, wherein the heart chamber includes an atrium of the heart. (5) The method of embodiment 1, wherein the heart chamber comprises a ventricle of the heart.

[0070] (6) The method of embodiment 1, wherein the region of ablated tissue comprises one or more discrete points. (7) The method of embodiment 1, wherein the region of ablated tissue comprises a line segment. (8) The method of embodiment 1, wherein displaying the valid annotation on the electroanatomical map includes deriving a local activation time (LAT) for the first location from the valid annotation and incorporating the LAT into the map. (9) The method of embodiment 1, wherein the first location is within a preset threshold distance from the region of ablated tissue. (10) The method of embodiment 9, wherein the preset threshold distance is 10 mm.

[0071] (11) An apparatus for electrophysiological evaluation, comprising: a display configured to present an electroanatomical map of the heart; and a probe configured to acquire electrical signals from myocardial tissue at a plurality of locations within a chamber of the heart proximate a region of ablated tissue; 1. A processor, comprising: deriving respective annotations from the electrical signals, the annotations indicating times within the cardiac cycle at which conducted waves in the myocardial tissue traversed the locations; identifying a first location at a first distance from the region of ablated tissue, the electrical signal including a dual potential signal having a first annotation and a second annotation at the first location at different respective times within the cardiac cycle; identifying a second location proximate the first location and at a second distance from the region of ablated tissue greater than the first distance, the electrical signal having a third annotation at the second location; selecting one of the first annotation and the second annotation that is closest to the third annotation as a valid annotation for the first location; and displaying the valid annotations on the electroanatomical map of the heart. (12) The device of embodiment 11, wherein the electrical signal at the second location comprises a single potential signal. (13) The device of embodiment 11, wherein the electrical signal at the second location comprises a dual-potential signal. (14) The device of embodiment 11, wherein the heart chamber includes an atrium of the heart. (15) The device of embodiment 11, wherein the heart chamber includes a ventricle of the heart.

[0072] (16) The device of embodiment 11, wherein the region of ablated tissue comprises one or more discrete points. (17) The device of embodiment 11, wherein the region of ablated tissue comprises a line segment. (18) The device of embodiment 11, wherein displaying the valid annotation on the electroanatomical map includes deriving a local activation time (LAT) for the first location from the valid annotation and incorporating the LAT into the map. (19) The device of embodiment 11, wherein the first location is within a preset threshold distance from the region of ablated tissue. (20) The device described in embodiment 19, wherein the preset threshold distance is 10 mm.

Claims

1. 1. A device for electrophysiological assessment, comprising: a display configured to present an electroanatomical map of the heart; and a probe configured to acquire electrical signals from myocardial tissue at a plurality of locations within a chamber of the heart proximate a region of ablated tissue; a tracking module configured to track a path of the probe within a mapping region that includes the heart; a processor in communication with the tracking module, recording the location of the ablated tissue and plotting the location on the electroanatomical map; storing the electrical signal; and deriving respective annotations from the electrical signals, the annotations indicating times within the cardiac cycle at which conducted waves in the myocardial tissue traversed the locations; storing the annotation and the location where the electrical signal providing the annotation was acquired; identifying a first location at a first distance from the region of ablated tissue, the electrical signal including a dual potential signal having a first annotation and a second annotation at the first location and at different respective times within the cardiac cycle; identifying a second location proximate the first location and at a second distance from the region of the ablated tissue greater than the first distance, the electrical signal having a third annotation at the second location; selecting one of the first annotation and the second annotation that is closest to the third annotation as a valid annotation for the first location; and displaying the valid annotations on the electroanatomical map of the heart.

2. The apparatus of claim 1 , wherein the electrical signal at the second location comprises a single potential signal.

3. The apparatus of claim 1 , wherein the electrical signal at the second location comprises a dual-potential signal.

4. The device of claim 1 , wherein the heart chamber comprises an atrium of the heart.

5. The device of claim 1 , wherein the heart chamber comprises a ventricle of the heart.

6. The device of claim 1 , wherein the region of ablated tissue comprises one or more discrete points.

7. The device of claim 1 , wherein the region of ablated tissue comprises a line segment.

8. 2. The apparatus of claim 1, wherein displaying the valid annotation on the electroanatomical map comprises deriving a local activation time (LAT) for the first location from the valid annotation and incorporating the LAT into the electroanatomical map.

9. The device of claim 1 , wherein the first location is within a preset threshold distance from the region of ablated tissue.

10. 10. The apparatus of claim 9, wherein the preset threshold distance is 10 mm.

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