Location-based pattern matching of coronary sinus (CS) signals

Abstract

The method includes acquiring a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals using a first catheter within the coronary sinus (CS) of a patient's heart while measuring the respective reference CS positions of the plurality of the first catheter during arrhythmia occurrence. One or more intracardiac electrophysiological (IC-EP) signals are acquired using a second catheter disposed within the heart chamber of the heart while acquiring an actual CS-EP signal using the first catheter and while measuring the actual CS position of the first catheter. Using the reference CS positions, reference CS-EP signals are identified. A signal stability between the actual CS-EP signal and the identified reference CS-EP signal is estimated. When the signal stability exceeds a given threshold, the identified reference CS-EP is utilized to verify whether one or more IC-EP signals acquired by the second catheter are acquired during the occurrence of an arrhythmia.

Description

Technical Field

[0001] The present disclosure generally relates to electrophysiological (EP) sensing using catheters, and more particularly to EP signal acquisition using pattern matching (PM) of intracardiac signals.

Background Art

[0002] Cardiac mapping techniques using reference signals have been previously reported in the patent literature. For example, U.S. Patent Application Publication No. 2017 / 0251942 describes an automated method for determining local activation time (LAT) from at least three multi-channel electrocardiogram signals including a mapping channel and a plurality of reference channels. The method includes (a) storing ventricular channel signals, (b) using the mapping channel signal and the first reference channel signal to calculate LAT values for a plurality of mapping channel positions, (c) monitoring the timing stability of the first reference channel signal, and (d) using the signal of the second reference channel to determine the LAT value when the monitored signal timing stability falls below a stability criterion. A substantial loss of LAT value is avoided despite the loss of timing stability.

[0003] As another example, U.S. Patent No. 11,213,235 describes a method including receiving (i) a plurality of electrocardiogram (ECG) signals acquired by a mapping catheter at a plurality of positions on the surface of a patient's heart, (ii) a reference ECG signal from a reference catheter positioned at a nominal position within the patient's coronary sinus (CS), and (iii) a position signal indicating the position of the reference catheter within the CS. By time-referencing the ECG signals relative to the reference ECG signal, an electrophysiological (EP) map of at least a portion of the heart is calculated. Based on the position signal, a displacement of the reference catheter from the nominal position within the CS that distorts the time reference is estimated. The estimated displacement is used to mitigate the distortion of the EP map.

[0004] U.S. Patent No. 11,071,486 describes a method of mapping cardiac excitation timing using a roving electrode attached to a catheter instead of a fixed (e.g., coronary sinus) electrode. The roving electrode is used to measure an initial electrophysiological signal at an initial cardiac position, which is defined as a reference signal. Local excitation arrival times for other cardiac positions measured using the roving electrode also attached to the catheter are determined relative to the reference signal. The stability of the reference signal can be monitored, for example, by comparing the excitation rate or cycle length between the instantaneously measured electrophysiological signal and the initial electrophysiological signal. A smaller difference (e.g., less than about 5%) between the two can be compensated for, while a larger difference can result in redefinition of the reference signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present disclosure will be more fully understood from the following detailed description of embodiments of the disclosure in conjunction with the drawings.

Figure 1

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DETAILED DESCRIPTION

[0006] Overview During electrophysiological (EP) mapping, a physician may wish to capture an arrhythmia event and determine its spatio-temporal distribution within the heart chamber. For this purpose, the physician uses an EP mapping catheter to EP map the ventricle. However, due to the local nature of EP acquisition, the physician or the processor of the EP mapping system cannot determine the relevance of a given EP signal because its relevance depends on whether an arrhythmia is actually occurring or has stopped at the time the signal was acquired.

[0007] To ensure that diagnostic EP signals are acquired during the occurrence of an arrhythmia, a physician may use a reference catheter, such as a coronary sinus (CS) catheter, to pre-capture a template of the arrhythmogenic coronary sinus electrophysiological (CS-EP) signal (also referred to as "intracardiac electrocardiogram (IC-ECG)") that manifests during the occurrence of an arrhythmia. The processor or the physician may then compare any newly acquired CS reference signal taken during EP acquisition with the template to verify that the mapping EP signal is clinically relevant (i.e., acquired during the occurrence of an arrhythmia).

[0008] In this way, an EP signal acquired at a certain tissue location within the heart cavity, hereinafter referred to as the "intracardiac electrophysiological (IC-EP) signal", which is mapped under the condition that there is a good correlation between the current IC-EP (e.g., IC-ECG) signal and the CS-EP (e.g., IC-ECG template), is received (e.g., for use in generating an EP map). This test, called pattern matching (PM) as used in IC PM, is a technique for obtaining a pattern from an IC catheter (mainly placed in the CS) rather than attempting to correlate an ECG signal obtained from electrodes attached to the skin, as the former method yields a more relevant arrhythmia origin pattern.

[0009] One drawback of this method is that the catheter within the CS tends to move over time. This movement reduces the IC PM correlation score to a non-usable correlation level (in one example, less than 75% after about 30 minutes). The reduction in correlation wastes time for the physician and the system to obtain a new pattern and construct a new EP map.

[0010] Embodiments of the present disclosure described herein provide techniques for achieving more accurate IC pattern matching in which an unexpected decrease in the correlation score is less likely to occur. The disclosed techniques include generating a pool of template IC patterns corresponding to different respective positions of the CS catheter. The pool is pre-stored so that it can be used whenever movement of the CS catheter is detected. For this purpose, the processor switches between pre-recorded IC patterns and identifies the pattern recorded at the CS position closest to the current CS catheter position. Before using the identified pattern, the processor verifies its accuracy by performing pattern matching (e.g., by comparing the correlation score between the actual pattern and the identified reference pattern with a predetermined threshold PM score).

[0011] In one embodiment, therefore, a method is provided that includes acquiring a plurality of sets of CS-EP signals using a first catheter within the coronary sinus (CS) of a patient's heart while measuring a plurality of respective reference CS positions of the first catheter (e.g., the CS catheter as defined above). One or more intracardiac electrophysiological (IC-EP) signals are acquired using a second catheter (e.g., the mapping catheter described above) disposed within the heart chambers of the heart while acquiring actual CS-EP signals using the first catheter and while measuring the actual CS position of the first catheter. Using the reference CS positions, a reference CS-EP signal is identified for which the reference CS position is closest to the actual CS position of the first catheter. Signal stability is estimated between the actual CS-EP signal and the identified reference CS-EP signal. Finally, if the signal stability exceeds a given threshold, the identified reference CS-EP is utilized to verify whether one or more IC-EP signals acquired by the second catheter are acquired during the occurrence of an arrhythmia.

[0012] To obtain the CS catheter position, in one embodiment, the CS catheter includes a magnetic sensor that is used to measure the CS catheter position. In another embodiment, electrical position detection may be used to track the CS position for each acquired pattern.

[0013] By introducing the disclosed features, there is a low likelihood of requiring the reacquisition of IC-ECG template patterns, which would involve the user wasting time to construct new maps with new patterns. Thus, an important advantage of this method is shortening the duration of the EP mapping procedure.

[0014] Accordingly, this technique includes an initial recording phase, where, prior to the EP mapping session, the user is prompted to move the CS catheter within the CS vein during arrhythmia and record a set of CS-EP template signal patterns as a function of the CS catheter position within the CS. While moving the CS catheter, the disclosed algorithm stores the pattern and its respective CS catheter position to generate a pool of sub-pattern templates (i.e., pattern and its respective position). This phase typically takes 10 - 30 seconds.

[0015] During EP mapping performed by an EP mapping catheter inserted into the target ventricle, the most recent position of the CS catheter is monitored so that the associated template can be selected from the set of patterns. The sub-pattern is automatically matched to the closest CS catheter position at which the sub-pattern is measured, thus overcoming CS movement that results in a decrease in the correlation score.

[0016] In one embodiment, during EP mapping, the processor switches between the stored template patterns (within the set) to select the pattern that best matches the actual CS catheter position. The switch can be automatically initiated based on tracking the movement of the CS catheter. The switch can also be manually triggered, for example, based on the user identifying a decreased correlation score (e.g., a PM score below a predetermined threshold). Alternatively, as described above, the switch between sub-patterns may not be available to the user, and the switch to another position-based pattern matching is automatically performed only by the processor.

[0017] In some embodiments, during the initial recording phase, the acquired IC-ECG patterns are filtered using, for example, a local activation time (LAT)-based filter that runs in the background (e.g., not available in user preference) to ensure that the same arrhythmia is being recorded. The filter rejects any acquired IC-ECG patterns when the LAT values on the reference signal do not match the "global" LAT values characteristic of an arrhythmia (such as atrial fibrillation) up to a tolerance.

[0018] Using a group of patterns instead of a single pattern results in fewer data points being rejected due to reduced correlation, so more data points are actually acquired. An experimentally observed 60% improvement in the number of acquired data points is reached, with thousands of additional EP data points being successfully acquired during EP mapping, which means that it may be possible to complete an EP map using a multi-electrode catheter without a single correlation failure.

[0019] The provided method includes obtaining a reference CS-EP signal, such as an IC-ECG signal, using a plurality of electrodes of a first catheter disposed at respective different measured CS positions within the coronary sinus (CS) of a patient's heart to generate a group of reference CS signals. While one or more IC-EP signals are obtained using one or more electrodes of a second catheter disposed within the heart chamber of the heart, the IC-EP signals are obtained using the first catheter to generate an actual CS reference signal at each respective actual CS position. The signal stability of each is estimated between the actual CS reference signal and the signals of the group of CS reference signals obtained at the CS position closest to the actual CS position. When the signal stability exceeds a given threshold, the one or more IC-EP signals obtained by the second catheter are utilized, for example, to generate EP map data points.

[0020] The signal stability can be the average of the stabilities of the signals from a plurality of electrodes, or particularly the minimum value among the stabilities. For example, assuming that a set of correlation levels is calculated for the signals from a set of electrodes, the measured value may be the average correlation level or the minimum correlation level in the set. When a correlation score or a PM score is provided, the score may be the average score or the minimum score among the set of scores calculated for the set of electrodes.

[0021] Typically, the processor is programmed with software including a specific algorithm that enables the processor to perform each of the processor-related processes and functions outlined above.

[0022] Description of the System FIG. 1 is a schematic depiction of a catheter 21-based electrophysiological (EP) sensing system 20 according to an embodiment of the present disclosure. Insert FIG. 15 in FIG. 1 shows the general anatomical structure of the heart. As can be seen, the right atrium collects deoxygenated blood from three sources: the superior vena cava (SVC), the inferior vena cava (IVC), and the SC that returns blood from the myocardium. In insert FIG. 25, the catheter 21 is inserted into the CS202 to collect an IC-ECG signal that may indicate atrial fibrillation originating from either the RA or the LA.

[0023] Catheter 21 comprises a deflectable tip portion 40 attached to the distal end of a shaft 22 of the catheter 21 having a plurality of electrodes 50. In the embodiments described herein, the physician 30 uses the catheter handle 32 to manipulate the sheath 23 of the catheter 21 inside the RA for the purpose of inserting the deflectable tip portion 40 into the CS202 such that, as depicted in FIG. 2, the distal portion of the electrode 50 overlaps the LA of the heart 26 to acquire an EP signal generated from the LA, while the proximal portion of the electrode 50 overlaps the RA of the heart 26 to acquire an EP signal generated from the RA. The IC-ECG signal may be a unipolar signal measured between the electrode 50 and the surface electrode 38 and, in the illustrated system, appears to be attached to the chest of the patient 28 lying on the table 29 by a wire passing through the cable 37.

[0024] The proximal end of the catheter 21 is connected to a control console 24 including an interface circuit 44. The electrodes 50 are connected by wires extending through the interface circuit 44 of the shaft 22 where the EP signals are received and processed (e.g., digitized) and output to a processor 41 within the console 24 for analysis.

[0025] The processor 41 may further receive an electrical impedance signal measured between the electrode 50 and the surface electrode 38. Methods for tracking the position of the electrode 50 using the measured impedance are implemented in various medical applications, e.g., in the CARTO (trademark) system manufactured by Biosense Webster (Irvine, Calif.) and are described in detail in U.S. Patent No. 8,456,182, assigned to the assignee of the present disclosure. The method may be referred to as Advanced Catheter Location (ACL). The console 24 drives a display 27 indicating the tracked position and / or shape of the deflectable tip portion 40 within the heart 26. Various signals, such as EP signals, are stored in the memory 46.

[0026] In some embodiments, system 20 further comprises a magnetic position sensing system for magnetically tracking the position of catheter 21 within CS202. For this purpose, console 24 further comprises a driver circuit 34 configured to drive a fixed magnetic field generator 36. As further seen, CS catheter 21 has a magnetic sensor 52 attached to a movable deflectable tip portion 40. During navigation of the deflectable tip portion 40, console 24 receives a position signal from magnetic sensor 52 in response to the magnetic field from fixed external magnetic field generator 36, from which a processor then calculates the tip position in the coordinate system of fixed magnetic field generator 36. The method of sensing position using an external magnetic field is implemented in various medical applications, such as in the CARTO™ system manufactured by Biosense Webster, and is described in detail in U.S. Patent Nos. 6,618,612 and 6,332,089, International Publication No. 96 / 05768, and U.S. Patent Application Publication Nos. 2002 / 0065455, 2003 / 0120150, and 2004 / 0068178, the disclosures of which are hereby incorporated by reference in their entirety.

[0027] Processor 41 configured within control console 24 is generally a general-purpose computer with a suitable front-end and interface circuit 44 for receiving signals from catheter 21 in the left atrium of heart 26 and controlling the other components of system 20. Processor 41 typically includes software within memory 48 of system 20 programmed to perform the functions described herein. The software can be downloaded to the computer in electronic form, for example, via a network, or alternatively or additionally provided and / or stored on a non-transitory tangible medium such as magnetic memory, optical memory, or electronic memory. Specifically, processor 41 executes a dedicated algorithm disclosed herein and included in FIG. 4 that enables processor 41 to perform the steps of the present disclosure, as further described below.

[0028] Movement of the CS catheter within the CS Figure 2 is a schematic depiction of the change 232 in the position of the CS catheter 21 within the coronary sinus (CS) 202, according to an embodiment of the present disclosure. In Figure 2, it can be seen that the deflectable tip portion 40 is displaced (232) between two positions, for example, the previous position 242 and the new actual position 252.

[0029] Such a change in position may render the IC-ECG pattern unfit for use because the PM score of the IC-ECG pattern falls below a threshold. However, when a new location 252 is measured using the disclosed technique, the processor switches between the stored template patterns (within the group) so as to select a pattern that most closely matches the actual CS catheter position 252.

[0030] Correlated IC-ECG signals and uncorrelated IC-ECG signals obtained by the CS catheter The processor 41 may calculate a correlation score for the IC-ECG signals obtained by the catheter 21 disposed within the CS using the method disclosed in U.S. Patent Application Publication No. 2021 / 0169359, assigned to the assignee of the present application. The processor applies a window of interest (WOI) to the IC-ECG signal representing the entire cycle length for a single heartbeat. The pattern of interest (POI) is selected to include a portion of the WOI corresponding to arrhythmic activity. A template POI is generated, which represents arrhythmic activity. Subsequent electrical activity is received, weighted, and compared to the template POI. A correlation score (also referred to herein as the "PM score") is generated.

[0031] Figures 3A and 3B are a set of graphs showing an actual IC-ECG signal 204 that correlates (3A) with a template pattern of the CS-EP signal 200 and an actual CS-EP signal 304 that does not correlate (3B) with another template pattern of the IC-ECG signal 300, based on all the signals (200, 204, 300, 304) obtained by the electrodes 50 of the CS catheter 21 of Figure 1 disposed within the CS 202, according to some embodiments of the present disclosure.

[0032] The actual CS-EP signals 204 and 304 were acquired during EP mapping. A correlation level, which can be either the average value or the minimum value across all electrodes, is provided on the displayed graph (175). As can be seen, the calculated correlation level or correlation score is very high (e.g., 0.9) between the actual CS signal and the reference signal in FIG. 3A, but very low (e.g., 0.2) between these signals in FIG. 3B.

[0033] The lack of correlation seen in FIG. 3B can occur due to the movement of the catheter 21 or because no arrhythmia was present when the signals were acquired. To overcome the low correlation due to the movement of the CS catheter, the processor switches between the stored template patterns (within the group) to select a pattern that most closely matches the actual CS catheter position, as described in FIG. 4.

[0034] Position-based pattern matching method for CS IC-ECG signals FIG. 4 is a flowchart schematically illustrating a method of position-based pattern matching of CS-EP (e.g., CS IC-ECG) signals according to an embodiment of the present disclosure. The algorithm is divided into a recording phase 401 and an EP mapping phase 411 according to the presented embodiment.

[0035] The recording phase 401 executes a process that begins with a CS catheter movement step 402, where the physician 30, as seen in FIG. 1, moves the deflectable tip section 40 of the catheter 21 within the CS 202 to record CS-EP patterns one at a time at tracked positions such as pattern 200 or 300.

[0036] Simultaneously, in a LAT filtering step 404, the processor 41 executes a LAT filter to verify that the CS-EP pattern is recorded when the investigated arrhythmia is active.

[0037] In the confirmation step 406, the processor checks whether the same arrhythmia has actually been recorded. For example, if the answer is "no" as estimated from the calculated ALT value, the processor drops the irrelevant IC-ECG patterns in the reference pattern drop step 408.

[0038] If the answer is "yes", the processor 41 saves the IC-ECG pattern (410) together with the qualified patterns as recorded and confirmed when the catheter is moved within the CS 202.

[0039] In the pattern clustering step 412, the processor clusters the qualified CS-EP patterns (i.e., CS IC-ECG patterns) and their respective positions within the folder for use during subsequent EP mapping sessions.

[0040] The ECG mapping stage 401 executes a process that begins with the CS catheter movement step 402, and the physician 30 moves the deflectable tip section 40 of the catheter 21 within the CS 202, as seen in FIG. 1, to record one IC-ECG pattern at a time at the tracked positions such as pattern 200 or 300.

[0041] When the physician uses an EP mapping catheter (not shown), such as a Pentaray (registered trademark) catheter, to obtain the actual CS pattern while acquiring the IC-ECG signal in the ventricle, the EP mapping stage 411 executes a process that begins with the EP signal acquisition step 422.

[0042] Next, the processor checks in the CS catheter position confirmation step 423 whether the CS catheter was stable during acquisition. The actual position can be determined using the magnetic detection method or the electrical detection method described above.

[0043] When the answer is "Yes", in the correlation score confirmation step 424, the processor 41 calculates the correlation between the current template of the CS-EP signal in use and the actual CS pattern obtained in step 422, applies the aforementioned method to the PM score, and compares it with a threshold value (e.g., threshold value = 0.75). When the PM score exceeds the threshold value, the processor saves the EP signal in the EP signal storage step 426. When the PM score is less than the threshold value, the processor 41 drops the EP signal in the EP signal drop step 425.

[0044] When the answer in step 424 is "No", which means the position of the CS catheter has changed, the processor 41 switches the stored template pattern (within the group) to select a pattern according to the closest actual position of the CS catheter in the reference IC pattern selection step 428.

[0045] In the second correlation score confirmation step 430, the processor 41 calculates the correlation between the template of the CS-EP signal selected in step 428 and the actual CS pattern obtained in step 422, applies the above-mentioned method to the PM score, and compares it with the threshold value. Here, when the PM score exceeds the threshold value, the processor saves the EP signal in the EP signal storage step 432. When the PM score is still less than the threshold value, the processor 41 drops the EP signal in the EP signal drop step 434. In any case, during mapping, the process returns to step 422 to obtain a new EP signal.

[0046] The flowchart in Figure 4 is simplified for clarity and is presented as an example. In reality, there may be additional steps such as notification and presentation of the EP map being constructed.

Example

[0047] (Example 1) The method includes, during the occurrence of an arrhythmia, using a first catheter (21) within the coronary sinus (CS) (202) of a patient's heart (26) to obtain a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals (200, 300) while measuring a plurality of respective reference CS positions of the first catheter (21). One or more intracardiac electrophysiological (IC-EP) signals are obtained using a second catheter disposed within the heart chambers of the heart while obtaining actual CS-EP signals (204, 304) using the first catheter and while measuring the actual CS position of the first catheter. Using the reference CS positions, a reference CS-EP signal whose reference CS position is closest to the actual CS position of the first catheter (21) is identified. The signal stability between the actual CS-EP signal and the identified reference CS-EP signal is estimated. When the signal stability exceeds a given threshold, the identified reference CS-EP is utilized to verify whether one or more IC-EP signals obtained by the second catheter were obtained during the occurrence of the arrhythmia.

[0048] (Example 2) The method according to Example 1, including generating one or more data points of an EP map of heart tissue during an arrhythmia using one or more IC-EP signals when it has been verified that one or more IC-EP signals were obtained during the arrhythmia.

[0049] (Example 3) The method according to any one of Examples 1 or 2, wherein estimating the signal stability includes estimating a level of correlation between the actual CS-EP signals (204, 304) and the identified reference CS-EP signal.

[0050] (Example 4) The method according to any one of Examples 1 to 3, wherein estimating the signal stability includes calculating a correlation score from the correlation level and comparing the correlation score with a predetermined threshold score.

[0051] (Example 5) The method according to any one of Examples 1 to 4, wherein the first catheter (21) comprises a distal end portion including a linear array (50) of electrodes.

[0052] (Example 6) Measuring the CS position includes obtaining a position signal using one or more electrodes (50) of the first catheter (21) and analyzing the position signal, and the method according to any one of Examples 1 to 5.

[0053] (Example 7) Measuring the CS position includes obtaining a position signal using a magnetic sensor (52) attached to the distal end portion of the first catheter (21) and analyzing the position signal, and the method according to any one of Examples 1 to 6.

[0054] (Example 8) The method according to any one of Examples 1 to 7, wherein the IC-EP signal is an IC electrocardiogram (ECG) signal.

[0055] (Example 9) The system (20) includes a first catheter (21), a second catheter, and a processor (41). The first catheter is disposed within the coronary sinus (CS) (202) of the heart (26) of a patient (28) and is configured to acquire a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals (200, 300) while measuring a plurality of respective reference CS positions of the first catheter during the occurrence of an arrhythmia. The second catheter is disposed within a cardiac chamber of the heart and is configured to acquire one or more intracardiac electrophysiological (IC-EP) signals while acquiring actual CS-EP signals (204, 304) using the first catheter and while measuring an actual CS position of the first catheter. The processor (41) is configured to: (a) use the reference CS positions to identify a reference CS-EP signal whose reference CS position is closest to the actual CS position of the first catheter; (b) estimate a signal stability between the actual CS-EP signals (204, 304) and the identified reference CS-EP signal; and (c) verify, when the signal stability exceeds a given threshold, whether one or more IC-EP signals acquired by the second catheter were acquired during the occurrence of an arrhythmia using the identified reference CS-EP.

[0056] It should be understood that the embodiments described above are given by way of example only, and the present disclosure is not limited to what is particularly illustrated and described above in this specification. Rather, the scope of the present disclosure includes both combinations and sub-combinations of the various features described above, as well as those variations and modifications thereof that would occur to a person skilled in the art upon reading the foregoing description and that are not disclosed in the prior art. Documents incorporated by reference into this patent application should be regarded as an integral part of this application, provided, however, that only the definitions in this specification are to be considered insofar as any terms in these incorporated documents are defined in a manner inconsistent with the definitions made explicitly or implicitly in this specification.

[0057] 〔Embodiments〕 (1) A method, comprising: During the occurrence of arrhythmia, while measuring the respective reference CS positions of the plurality of the first catheters using the first catheter within the coronary sinus (CS) of the patient's heart, acquiring a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals; While acquiring the actual CS-EP signal using the first catheter and measuring the actual CS position of the first catheter, acquiring one or more intracardiac electrophysiological (IC-EP) signals using a second catheter disposed within the heart chamber of the heart; Using the reference CS position, identifying the reference CS-EP signal whose reference CS position is closest to the actual CS position of the first catheter; Estimating the signal stability between the actual CS-EP signal and the identified reference CS-EP signal; When the signal stability exceeds a given threshold, using the identified reference CS-EP to verify whether the one or more IC-EP signals acquired by the second catheter are acquired during the occurrence of the arrhythmia. A method comprising. (2) When verifying that the one or more IC-EP signals are acquired during the arrhythmia, using the one or more IC-EP signals to generate one or more data points of an EP map of the heart tissue during the arrhythmia. The method according to embodiment 1, comprising. (3) The method according to embodiment 1, wherein estimating the signal stability includes estimating a correlation level between the actual CS-EP signal and the identified reference CS-EP signal. (4) The method according to embodiment 3, wherein estimating the signal stability includes calculating a correlation score from the correlation level and comparing the correlation score with a predetermined threshold score. (5) The method according to embodiment 1, wherein the first catheter comprises a distal end portion including a linear array of electrodes.

[0058] (6) Measuring the CS position includes obtaining a position signal using one or more electrodes of the first catheter and analyzing the position signal, the method according to Embodiment 1. (7) Measuring the CS position includes obtaining a position signal using a magnetic sensor attached to the distal end of the first catheter and analyzing the position signal, the method according to Embodiment 1. (8) The method according to Embodiment 1, wherein the IC-EP signal is an intracardiac electrocardiogram (ECG) signal. (9) A system, A first catheter disposed within the coronary sinus (CS) of a patient's heart, configured to obtain a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals while measuring a plurality of respective reference CS positions of the first catheter during the occurrence of an arrhythmia, a first catheter; A second catheter disposed within the cardiac chamber of the heart, configured to obtain one or more intracardiac electrophysiological (IC-EP) signals while obtaining an actual CS-EP signal using the first catheter and while measuring an actual CS position of the first catheter, a second catheter; A processor, wherein the processor uses the reference CS position to identify a reference CS-EP signal whose reference CS position is closest to the actual CS position of the first catheter, estimates a signal stability between the actual CS-EP signal and the identified reference CS-EP signal, and is configured to verify whether the one or more IC-EP signals obtained by the second catheter are obtained during the occurrence of the arrhythmia using the identified reference CS-EP when the signal stability exceeds a given threshold, a processor; A system comprising. (10) The system according to embodiment 9, wherein when verifying that the one or more IC-EP signals are acquired during the arrhythmia, the processor is further configured to use the one or more IC-EP signals to generate one or more data points of an EP map of cardiac tissue during the arrhythmia.

[0059] (11) The system according to embodiment 9, wherein the processor is configured to estimate the signal stability by estimating a correlation level between the actual CS-EP signal and the identified reference CS-EP signal. (12) The system according to embodiment 11, wherein the processor is further configured to calculate a correlation score from the correlation level and compare the correlation score with a predetermined threshold score to estimate the signal stability. (13) The system according to embodiment 10, wherein the first catheter comprises a distal end portion including a linear array of electrodes. (14) The system according to embodiment 10, wherein measuring the CS position includes acquiring a position signal using one or more electrodes of the first catheter and analyzing the position signal. (15) The system according to embodiment 10, wherein measuring the CS position includes acquiring a position signal using a magnetic sensor attached to the distal end portion of the first catheter and analyzing the position signal.

[0060] (16) The system according to embodiment 10, wherein the IC-EP signal is an intracardiac electrocardiogram (ECG) signal.

Claims

**Claim 1** A system comprising: A first catheter configured to be disposed within a coronary sinus (CS) of a patient's heart and to acquire a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals while measuring a plurality of respective reference CS positions of the first catheter during the occurrence of an arrhythmia; A second catheter configured to be disposed within a heart chamber of the heart and to acquire one or more intracardiac electrophysiological (IC-EP) signals while acquiring an actual CS-EP signal using the first catheter and while measuring an actual CS position of the first catheter; A processor, wherein the processor is: Using the reference CS position, identifying a reference CS-EP signal whose reference CS position is closest to the actual CS position of the first catheter; Estimating a signal stability between the actual CS-EP signal and the identified reference CS-EP signal; And configured to verify, when the signal stability exceeds a given threshold, whether the one or more IC-EP signals acquired by the second catheter were acquired during the occurrence of the arrhythmia using the identified reference CS-EP. A system comprising the processor. **Claim 2** The system of claim 1, wherein the processor is further configured to generate one or more data points of an EP map of heart tissue during the arrhythmia using the one or more IC-EP signals when verifying that the one or more IC-EP signals were acquired during the arrhythmia. **Claim 3** The system of claim 1, wherein the processor is configured to estimate the signal stability by estimating a correlation level between the actual CS-EP signal and the identified reference CS-EP signal. **Claim 4** The system of claim 3, wherein the processor is further configured to estimate the signal stability by calculating a correlation score from the correlation level and comparing the correlation score with a predetermined threshold score. **Claim 5** The system of claim 2, wherein the first catheter comprises a distal end portion including a linear array of electrodes. **Claim 6** The system of claim 2, wherein measuring the CS position includes obtaining a position signal using one or more electrodes of the first catheter and analyzing the position signal.

7. The system of claim 2, wherein measuring the CS position includes obtaining a position signal using a magnetic sensor attached to the distal end of the first catheter and analyzing the position signal.

8. The system of claim 2, wherein the IC-EP signal is an intracardiac electrocardiogram (ECG) signal.

9. A method comprising: During the occurrence of an arrhythmia, while measuring a plurality of respective reference CS positions of the first catheter within the coronary sinus (CS) of a patient's heart using the first catheter, obtaining a plurality of sets of reference coronary sinus electrophysiological (CS-EP) signals; While obtaining an actual CS-EP signal using the first catheter and while measuring the actual CS position of the first catheter, obtaining one or more intracardiac electrophysiological (IC-EP) signals using a second catheter disposed within the heart chamber of the heart; Using the reference CS position to identify a reference CS-EP signal whose reference CS position is closest to the actual CS position of the first catheter; Estimating a signal stability between the actual CS-EP signal and the identified reference CS-EP signal; When the signal stability exceeds a given threshold, verifying whether the one or more IC-EP signals obtained by the second catheter are obtained during the occurrence of the arrhythmia using the identified reference CS-EP.

10. The method of claim 9, further comprising generating one or more data points of an EP map of heart tissue during the arrhythmia using the one or more IC-EP signals when it is verified that the one or more IC-EP signals are obtained during the arrhythmia.

11. The method of claim 9, wherein estimating the signal stability includes estimating a correlation level between the actual CS-EP signal and the identified reference CS-EP signal.

12. The method of claim 11, wherein estimating the signal stability includes calculating a correlation score from the correlation level and comparing the correlation score with a predetermined threshold score.

13. The method according to claim 9, wherein the first catheter comprises a distal end portion including a linear array of electrodes.

14. The method according to claim 9, wherein measuring the CS position includes obtaining a position signal using one or more electrodes of the first catheter and analyzing the position signal.

15. The method according to claim 9, wherein measuring the CS position includes obtaining a position signal using a magnetic sensor attached to the distal end portion of the first catheter and analyzing the position signal.

16. The method according to claim 9, wherein the IC-EP signal is an intracardiac electrocardiogram (ECG) signal.

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