Systems and methods for clustering wavefront signals in electrophysiological maps

Abstract

To provide a system and method for clustering wavefront signals in an electrophysiological map of a cardiac tissue.SOLUTION: The system and method include receiving an electrophysiological map of the cardiac tissue, displaying propagation of the wavefront signals as a plurality of velocity vectors, discretizing the received electrophysiological map into a plurality of sections, clustering the velocity vectors into at least one group within each section based on predefined criteria, and generating a trend line representative of each group of clustered velocity vectors within each section in the electrophysiological map.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system, method, apparatus, and program for clustering wavefront signals to simplify electrophysiological maps. [Background technology]

[0002] Visualization of cardiac structures is important for monitoring and diagnosing cardiac health, as well as for performing certain cardiac procedures. For example, as a prerequisite for performing cardiac procedures, electrophysiological (EP) studies are often performed to generate electrophysiological (EP) cardiac maps that can display three-dimensional, or 3D, mapping data on a monitor.

[0003] Various methods are known in the art for reconstructing a 3D EP map of a cardiac chamber or volume using known position coordinates of multiple locations on the surface of the chamber or volume. One example of cardiac EP mapping requires determining the velocity and direction of propagation of electrical signals through cardiac tissue. Abnormal propagation velocity or vortex signal flow may be diagnostic of locally diseased cardiac tissue, which can be treated, for example, by ablation.

[0004] Typically, cardiac signal propagation velocity is measured by sensing wavefront signals at multiple electrodes in contact with the inner surface of a heart chamber. One known method for measuring cardiac signal propagation velocity utilizes measurements of the local activation time (LAT) of cardiac tissue relative to the cardiac cycle at multiple sampling points on the inner surface of a heart chamber using a device such as a catheter that senses electrical activity at the point where the catheter tip contacts the inner surface of the heart chamber. These LAT measurements can be displayed on an EP cardiac map as conduction velocity vectors and represented, for example, by arrows at the measurement points, with the direction of the arrow representing the wavefront's propagation direction and the length of the arrow representing the wavefront's propagation velocity. These arrows provide a visual indication of the propagation velocity, allowing a physician to identify the location of diseased cardiac tissue to be treated. Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, the amount of graphical information in the form of vectors or arrows is considerable and difficult to interpret, especially for untrained physicians. To enable physicians to more easily understand the wavefront information, it would be advantageous to be able to view EP cardiac maps showing the propagation direction and propagation velocity of wavefront signals in a simplified format that reduces the amount of information presented by the vectors of current EP mapping systems. [Means for solving the problem]

[0006] Disclosed herein are systems, methods, devices, and programs for clustering wavefront signals to simplify electrophysiological (EP) maps.

[0007] According to one aspect, the subject matter disclosed herein relates to a method for clustering wavefront signals in an electrophysiological map of cardiac tissue, the method including providing a processor configured to receive an electrophysiological map of cardiac tissue, displaying propagation of the wavefront signals as a plurality of velocity vectors, discretizing the received electrophysiological map into a plurality of sections, clustering the velocity vectors into at least one group within each section based on a predefined criterion, and generating trend lines representing each group of clustered velocity vectors within each section in the electrophysiological map.

[0008] According to another aspect, the subject matter disclosed herein relates to a system for clustering wavefront signals in an electrophysiological map of cardiac tissue, comprising: a processor with memory configured to receive an electrophysiological map of cardiac tissue displaying propagation of the wavefront signals as a plurality of velocity vectors, discretize the received electrophysiological map into a plurality of sections, cluster the velocity vectors into at least one group within each section based on a defined criterion, and generate trend lines representing each group of clustered velocity vectors within each section in the electrophysiological map.

[0009] According to yet another aspect, the subject matter disclosed herein relates to a computer-readable storage medium having stored thereon program instructions for clustering wavefront signals within an electrophysiological map of cardiac tissue, the program instructions causing a computer to receive an electrophysiological map of cardiac tissue, display the propagation of the wavefront signals as a plurality of velocity vectors, discretize the received electrophysiological map into a plurality of sections, cluster the velocity vectors into at least one group within each section based on a predefined criterion, generate trend lines representing each group of clustered velocity vectors within each section within the electrophysiological map, and display the trend lines within the electrophysiological map on a display. [Brief explanation of the drawings]

[0010] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numerals indicate similar elements and in which: [Figure 1] 1 illustrates an exemplary electrophysiological (EP) mapping system capable of implementing one or more features of the disclosed subject matter, according to disclosed embodiments of the present application. [Figure 2] 1 illustrates a catheter within a patient's heart, according to a disclosed embodiment of the present application. [Figure 3]FIG. 1 shows a view of a 3D EP map showing local activation times (LATs) associated with cardiac tissue, with conduction velocity vectors superimposed as arrows. [Figure 4] 1 illustrates an exemplary 3D EP map of cardiac tissue including multiple trend lines conveying the propagation of a wavefront signal, according to a disclosed embodiment of the present application. [Figure 5] 1 illustrates an exemplary 3D EP map of cardiac tissue showing a single trend line conveying the propagation of a wavefront signal across the cycle length, according to a disclosed embodiment of the present application. [Figure 6] FIG. 1 is a flow diagram illustrating an exemplary embodiment of a process for generating trend lines representing wavefront propagation in an EP map of cardiac tissue utilizing a clustering algorithm, in accordance with a disclosed embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0011] Disclosed herein are systems, methods, devices, and programs for clustering wavefront signals to simplify electrophysiological (EP) maps.

[0012] Treatment of cardiac disorders, such as cardiac arrhythmias, often requires obtaining detailed mapping of cardiac tissue, chambers, veins, arteries, and / or electrical pathways. For example, as a prerequisite for successful catheter ablation, cardiac arrhythmias must be accurately located within a cardiac chamber. Such localization can be performed via electrophysiological studies, during which electrical potentials are detected by a mapping catheter introduced into the cardiac chamber. This electrophysiological study, often referred to as EP mapping, provides 3D mapping data that can be displayed on a monitor. Often, mapping and therapy functions (e.g., ablation) are provided by a single catheter or group of catheters; thus, the mapping catheter also simultaneously operates as a therapy (e.g., ablation) catheter.

[0013] Mapping cardiac regions, such as the heart, cardiac tissue, veins, arteries, and / or electrical pathways, can result in the identification of problem areas, such as scar tissue, arrhythmia sources (e.g., electrical rotors), healthy regions, etc. Cardiac regions can be mapped such that a visual rendering of the mapped cardiac region is provided using a display, as further disclosed herein. Additionally, cardiac mapping can include mapping based on one or more modalities, such as, but not limited to, local activation time (LAT), electrical activity, topology, bipolar mapping, dominant frequency, or impedance. Data corresponding to multiple modalities can be captured using catheters inserted within the patient's body and provided for rendering simultaneously or at different times based on corresponding settings and / or medical professional preferences.

[0014] In one embodiment, EP cardiac mapping can be performed by sensing electrical properties of cardiac tissue, such as local activation time (LAT), as a function of precise location within the heart. The corresponding data can be acquired using one or more catheters advanced into the heart using catheters having electrical and location sensors at their distal tips. By way of example, location and electrical activity can be measured at hundreds or thousands of cardiac points or sites to generate a detailed, comprehensive map of the electrical activity of the heart chambers. The detailed map generated can then serve as a basis for making decisions regarding therapeutic courses of action, such as tissue ablation, to alter the propagation of cardiac electrical activity and restore normal cardiac rhythm.

[0015] In one embodiment, electrical activity at a point within the heart can be measured by advancing a catheter including an electrical sensor at or near its distal tip to the point within the heart, contacting tissue with the sensor, and acquiring data at the point. Such catheter-containing electrical and / or sensor-based devices can also be used to determine the velocity and direction of cardiac wavefront signals at the measurement point on the heart's surface. An EP map representing such motion characteristics can be constructed when wavefront velocity and direction information is sampled at a sufficient number of points within the heart. According to another example, body patches and / or body surface electrodes can be placed on or adjacent to the patient's body. A catheter with one or more electrodes can be positioned within the patient's body (e.g., within the patient's heart), and the position of the catheter can be determined by the system based on signals transmitted and received between one or more electrodes on the catheter and the body patch and / or body surface electrodes. Additionally, the catheter electrodes can sense physiological data (e.g., LAT values) from within the patient's body (e.g., within the heart). The biometric data may be associated with the determined catheter position, such that a rendering of the patient's body part (e.g., the heart) may be displayed showing the biometric data superimposed on the shape of the body part as measured for each catheter position.

[0016] FIG. 1 is a diagram of an exemplary EP mapping system 100 capable of implementing one or more features of the disclosed subject matter. EP mapping system 100 may include one or more biometric devices 120, such as a catheter 140 (shown in inset 145). For example, but not limited to, biometric device 120 may be configured to acquire biometric data, such as imaging signals, electrical signals, wavefront propagation information, etc. Those skilled in the art will recognize that catheter 140 may be of any shape and may include one or more elements (e.g., electrodes or sensors) used to implement the embodiments disclosed herein. EP mapping system 100 includes a probe 121 having one or more shafts 122 that can be navigated by a physician 130 into a body part, such as a heart 126, of a patient 128 residing on a table 129. According to exemplary embodiments, multiple probes 121 may be provided; however, for simplicity, a single probe 121 is described in this example. However, it will be understood that probe 121 may represent multiple probes. As shown in FIG. 1 , a physician 130 may insert a probe 121 through a sheath 123 while manipulating a shaft 122 at the distal end of the probe 121 using a manipulator near the proximal end of the invasive device and / or deflection from the sheath 123. As shown in inset 225, a bioinstrumentation device 120 may be fitted to the distal end of the probe 121. The bioinstrumentation device 120 may be inserted through the sheath 123 to acquire biometric data of the heart 126. For example, inset 145 shows a close-up view of a catheter 140 inside a chamber of the heart 126. As shown, the catheter 140 may include a tip 146 having at least one measurement device 147 for measuring biometric or physiological information of the heart 126.

[0017] According to embodiments disclosed herein, the biological information may also include one or more of LAT, electrical activity, topology, bipolar mapping, dominant frequency, impedance, etc. The local activation time may be the time point of a threshold activation corresponding to local activation calculated based on a normalized initial onset. The electrical activity may be any applicable electrical signal that can be measured based on one or more thresholds and detected and / or enhanced based on signal-to-noise ratio and / or other filters. The topology may correspond to the physical structure of a body part or a portion of a body part, or may correspond to changes in the physical structure for different portions of the body part or for different body parts. The dominant frequency may be a frequency or range of frequencies prevalent in a portion of a body part and may differ in different portions of the same body part. For example, the dominant frequency of the pulmonary veins of a heart may be different from the dominant frequency of the right atrium of the same heart. The impedance may be a resistance measurement in a given region of a body part.

[0018] 1 , the probe 121 may be connected to a console 124. The console 124 may include a processor 141, such as a general-purpose computer, with suitable front-end and interface circuitry 138 for sending and receiving signals with the biodevice 120 and for controlling other components of the EP mapping system 100. In some embodiments, the processor 141 may be further configured to receive biometric data, such as electrical activity, and determine whether a given tissue region conducts electricity. According to one embodiment, the processor may be external to the console 124, for example, located in a catheter, an external device, a mobile device, a cloud-based device, or may be a stand-alone processor.

[0019] As mentioned above, the processor 141 may include a general-purpose computer, which may be programmed with software to perform the functions described herein. The software may be downloaded in electronic form to the general-purpose computer, for example, over a network, or alternatively or additionally, may be provided and / or stored on a non-transitory tangible medium, such as magnetic, optical, or electronic memory. The exemplary configuration shown in FIG. 1 may be modified to implement embodiments disclosed herein. Embodiments of the present disclosure may be similarly applied using other system components and configurations. Additionally, the EP mapping system 100 may include additional components, such as elements for sensing electrical activity, wired or wireless connectors, processing and display devices, etc.

[0020] According to one embodiment, the display 127 connected to a processor (e.g., processor 141) may be located at a remote location, such as a separate hospital, or within a separate healthcare provider network. Additionally, the EP mapping system 100 may be part of a surgical system configured to obtain anatomical and electrical measurements of a patient's organs, such as the heart, and to perform cardiac ablation procedures. One example of such a surgical system is the CARTO® system sold by Biosense Webster.

[0021] EP mapping system 100 may also, and optionally, acquire biometric data, such as anatomical measurements of the patient's heart, using ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), or other medical imaging techniques known in the art. EP mapping system 100 may acquire electrical measurements using catheter 140, body surface electrodes 143, or other sensors that measure electrical properties of the heart. The biometric data, including the anatomical and electrical measurements, may then be stored in memory 142 of EP mapping system 100, as shown in FIG. 1 . The biometric data may be transmitted from memory 142 to processor 141. Alternatively, or in addition, the biometric data may be transmitted to server 160, which may be local or remote, using network 162. Server 160 may include a processing unit for additional review, analysis, and processing of the biometric data.

[0022] Network 162 may be any network or system commonly known in the art, such as an intranet, a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), a direct connection or series of connections, a cellular telephone network, or any other network or medium capable of facilitating communication between EP mapping system 100 and server 160. Network 162 may be wired, wireless, or a combination thereof. Wired connections may be implemented using Ethernet, Universal Serial Bus (USB), RJ-11, or any other wired connection commonly known in the art. Wireless connections may be implemented using Wi-Fi, WiMAX, Bluetooth, infrared, cellular networks, satellite, or any other wireless connection method commonly known in the art. Additionally, several networks may operate alone or in communication with each other to facilitate communication within network 162.

[0023] In some cases, server 160 may be implemented as a physical server. In other cases, server 162 may be implemented as a virtual server, a public cloud computing provider (e.g., Amazon Web Services (AWS)).

[0024] Processor 141 may include real-time noise reduction circuitry, typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A / D) ECG (electrocardiograph) or EMG (electromyogram) signal conversion integrated circuit. Processor 141 may pass signals from the A / D ECG or EMG circuitry to another processor and / or may be programmed to perform one or more of the functions disclosed herein.

[0025] The control console 124 may also include an input / output (I / O) communication interface that allows the control console to transfer signals to and / or from the biometric device 120 .

[0026] During or after the procedure, processor 141 may facilitate presentation of body part rendering 135 to physician 130 on display 127 and store data representing body part rendering 135 in memory 142. Memory 142 may comprise any suitable volatile and / or non-volatile memory, such as random access memory or a hard disk drive. In some embodiments, medical professional 130 may be able to manipulate body part rendering 135 using one or more input devices, such as a touchpad, a mouse, a keyboard, a gesture recognizer, or the like. For example, using the input device, the position of catheter 140 may be changed so that rendering 135 is updated. In an alternative embodiment, display 127 may include a touch screen that may be configured to receive input from medical professional 130 in addition to presenting body part rendering 135.

[0027] 2 shows an exemplary embodiment of a distal end 222 of a catheter 140 positioned within a heart 126 of a patient 128, according to one embodiment of the present application. The catheter 140 is inserted into the heart 126, and the tip 146 is brought into contact with multiple locations, such as location 220, on an inner surface 272 of the heart 126. At each of the multiple locations, coordinates of the tip 146 are determined by a measuring device 147. The determined coordinates, and optionally, physiological information, form local data points.

[0028] In one embodiment, an example of a physiological parameter of the heart 126 measured using the measurement device 147 of the catheter 140 is the local activation time (LAT) of the cardiac tissue. This time is determined by referencing the time of a signal (specifically, voltage) feature measured by the functional measurement device 147 at each sampling point, e.g., the time in the cardiac cycle when the signal first exceeds a certain threshold, to the time within the cardiac cycle of a reference feature of the ECG signal, as measured, for example, using an ECG monitor. The propagation velocity of the LAT signal, i.e., the conduction velocity of the cardiac tissue, is obtained by assigning a velocity vector to each sampling point based on the measured LAT signal value using methods known to those skilled in the art, such as those described in U.S. Patent No. 6,301,496, which is incorporated by reference as if fully set forth. The conduction velocity vectors can be superimposed as arrows on a 3D model of the heart or cardiac segments in an EP mapping system such as system 100. In one embodiment, the direction of the arrow represents the propagation direction of the wavefront signal, and the length of the arrow represents the propagation velocity of the wavefront. These arrows provide a visual representation of the conduction velocity of the cardiac tissue, allowing the physician to assess and determine how to treat the diseased cardiac tissue.

[0029] Conventional 3D EP mapping systems typically present hundreds or thousands of velocity vectors, making it difficult to interpret the conduction velocity vectors superimposed as arrows on a 3D model of a heart or heart segment. FIG. 3 is an exemplary embodiment of a 3D EP map showing local activation times (LATs) associated with cardiac tissue. The cardiac tissue may be, for example, but not limited to, a cardiac chamber (e.g., an atrial cavity, the left atrium, or the right atrium). The LATs are indicative of the flow of electrical activity through the wall of the heart. Specifically, FIG. 3 shows conduction velocity vectors superimposed as arrows. As shown in FIG. 3, the number of conduction velocity vectors can be large, tedious, and difficult to follow, especially for inexperienced physicians.

[0030] In one embodiment, the present subject matter aims to simplify 3D EP cardiac maps by reducing the amount of information presented. More specifically, the present subject matter aims to utilize a clustering algorithm to generate trend lines instead of individual velocity vectors to illustrate wavefront propagation in cardiac tissue. The output of the clustering algorithm conveys similar information as a traditional LAT map, but the graphical information is reduced as a result of clustering multiple conduction velocity vectors into one or several trend lines. For example, to illustrate the propagation of a wavefront signal, multiple trend lines (410, 415, 420, 430, 435, 440, 450), discussed in more detail herein, can be superimposed on the EP map 400, as shown in FIG. 4, or a single trend line 510, discussed in more detail herein, can be superimposed on the EP map 500, as shown in FIG. 5.

[0031] FIG. 6 is an exemplary embodiment of a process 600 for generating trend lines representing wavefront propagation in an EP map of cardiac tissue utilizing the clustering algorithm of the present application.

[0032] At step 610, a processing device, such as processor 141 and memory 142, associated with EP mapping system 100 (FIG. 1) preferably receives and stores an EP map of the cardiac chamber or region of interest. The processing device can be co-located with the EP mapping system, or can be located remotely from the EP mapping system or stored in the cloud. In one embodiment, the EP map is a 3D EP map showing LAT associated with cardiac tissue, such as, for example, but not limited to, EP map 300 shown in FIG. 3, which shows a large number of conduction velocity vectors.

[0033] In step 620, the processing unit preferably discretizes the EP map into isochronous sections. For example, Figure 3 shows isochronous sections 310, 320, 330, 340, and 350 generated by color discretization of the EP map. In one embodiment, the color is inserted into the map as a representation of the local activation time (LAT) of each point, and each color is mapped to a number, such as, but not limited to, a number representing a time or amount of time. The isochronous sections 310, 320, 330, 340, and 350 are generated by dividing the color or time points on the EP map into several time segments, and referencing each common time segment to one isochronous segment.

[0034] In one embodiment, the color and velocity vectors can currently be determined as a result of the "coherent" algorithm in the CARTO® system described above. This system can be modified by those skilled in the art to embody the principles described herein. Those skilled in the art will recognize that other systems, methods, and algorithms can be utilized to calculate the LAT (wave time) and direction (velocity vector) for each point in the EP map in accordance with the subject matter of the present application, such as those disclosed in commonly assigned U.S. Patent Nos. 10,282,888 and 10,674,929, which are incorporated by reference as if fully set forth. For example, the color can be interpolated over a given time on the EP map using a Laplace operator, and the velocity vector can be derived by calculating the distinct gradients over the time function.

[0035] While five isochronous sections are shown in Figure 3, those skilled in the art will recognize that any number of isochronous sections may be generated without departing from the subject matter of this application. While the term "coloring" is used herein with reference to an EP map, those skilled in the art will recognize that within the scope of this application, "coloring" may include variations based on color, brightness, or grayscale ranges that indicate different times associated with each isochronous section.

[0036] At step 630, the processing unit preferably applies a clustering algorithm according to the present application to cluster or group the conduction velocity vectors from multiple points within the isochronous section. For example, but not limited to, the clustering algorithm may group the conduction velocity vectors based on predefined criteria such as predefined proximity, common direction, or common propagation velocity. In one embodiment, the predefined criteria may be set by a user, such as a physician, or may be determined as a result of a machine learning algorithm employed by the processing unit.

[0037] At step 640, the processing unit preferably generates at least one trend line within each isochronal section in the EP map that represents the grouped conduction velocity vectors. Figure 4 shows an exemplary embodiment of a 3D EP map 400 of a cardiac structure showing trend lines 410, 415, 420, 430, 435, 440, 450 that represent the grouped velocity vectors. For example, - trend lines 410 and 415 represent the grouped velocity vectors in the isochronous section 310; The trend lines 420 represent the grouped velocity vectors within the isochronous section 320; - trend lines 430 and 435 represent the grouped velocity vectors within the isochronous section 330; The trend lines 440 represent the grouped velocity vectors within the isochronous section 340; The trend lines 450 represent the clustered velocity vectors within the isochronous section 350 .

[0038] 4, for example, trend lines 410, 415, 420, 430, 435, 440, 450 may be visually indicated by arrows. However, one skilled in the art will readily appreciate that trend lines are not limited to arrows and that trend lines may be visually indicated using other graphical indicators such as lines, dots, x's, color patterns, etc.

[0039] The number of trend lines generated within each isochrone section can be based on predetermined criteria. For example, two trend lines 410, 415 are generated within isochrone 310 in Figure 4, and the clustering algorithm can be programmed to generate a single trend line within each isochrone, or to generate two or more trend lines within each isochrone, based on predefined criteria.

[0040] 5 illustrates an exemplary embodiment of a 3D EP map 500 of cardiac structures showing a single trend line 510 representing the grouped velocity vectors in an isochronal section generated by the clustering algorithm described herein. As shown in FIG. 5, the single trend line 510 can have a circular pattern representing the propagation of the wavefront signal throughout the cardiac cycle length.

[0041] At step 650, the trend lines generated in the EP map may be displayed on a display, such as display 127 (FIG. 1). Alternatively, the trend lines generated in the EP map may be displayed on a remote display (e.g., a display associated with server 160). In one embodiment, the trend lines are displayed without the conduction velocity vectors, as shown in FIG. 4. Alternatively, the trend lines may be overlaid on the conduction velocity vectors and visually distinguished, such as by different grayscales, colors, or patterns.

[0042] The presently disclosed subject matter for clustering wavefront information for representation in an EP map provides a more simplified visualization of the propagation of electromagnetic wavefront signals traveling through cardiac structures compared to their display in conventional EP maps. This is achieved by reducing the clutter caused by hundreds or thousands of velocity vectors presented in conventional EP maps and providing a condensed visualization of a limited number of trend lines representing groups of conduction velocity vectors. The trend line information conveys similar information as conventional conduction velocity vectors, but is presented in a graphical display that is easier to understand, especially for novice physicians.

[0043] The isochronous segment generation described herein reduces the complexity of determining the propagation of a wavefront signal. As described herein, trend lines are generated within each isochronous region representing the wavefront propagation. As a result, the greater the number of isochronous regions in a given space, the more accurate the trend lines generated in the EP map.

[0044] While the above description is generally directed to having a processing device that analyzes local activation times of cardiac tissue, it will be understood that the subject matter of the present application is not so limited and may be applied to other physiological parameters associated with other body organs. For example, the processing device may be configured to operate and cluster by voltage across the organ rather than by time. As another example, during ablation of an organ, there is heat flow, and the heat flow through the organ may manifest itself as a change in the temperature of the organ. The processing device may be configured to analyze and cluster the measured temperature of the organ. Those skilled in the art will be able to identify other physiological parameters to which a processing device may be applicable within the scope of the present application.

[0045] It should be understood that many variations are possible based on the disclosure herein. While features and elements are described above in particular combinations, each feature or element may be used alone without the other features and elements, or in various combinations with other features and elements, with or without the other features and elements. Similarly, although process steps are described above in a particular order, the steps may be performed in any other desired order.

[0046] The methods, processes, and / or flowcharts provided herein may be implemented in a computer program, software, or firmware embodied in a non-transitory computer-readable storage medium for execution by a general-purpose computer or processor. Examples of non-transitory computer-readable storage media include ROM, random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs).

[0047] Certain terminology is used in this description merely for convenience and is not limiting. The words "a" and "one," when used in the claims and corresponding portions of this specification, are defined to include one or more of the referenced items, unless otherwise specified. This terminology includes the words specifically mentioned above, derivatives thereof, and words of similar import. The phrase "at least one" followed by a list of two or more items, such as "A, B, or C," means any individual one of A, B, or C, and any combination thereof.

[0048] Further exemplary embodiments of the present specification may be formed by adding to an embodiment one or more elements from any one or more other embodiments of the present specification and / or by substituting one or more elements from an embodiment with one or more elements from one or more other embodiments of the present specification.

[0049] It is understood, therefore, that the disclosed subject matter is not limited to the particular embodiments disclosed, but is intended to encompass all modifications that are within the spirit and scope of the present invention as defined by the appended claims, the above description, and / or as illustrated in the accompanying drawings.

[0050] [Embodiment] (1) A method for clustering wavefront signals in an electrophysiological map of cardiac tissue, comprising: providing a processor configured to receive an electrophysiological map of the cardiac tissue; representing the propagation of the wavefront signal as a plurality of velocity vectors; discretizing the received electrophysiological map into a plurality of sections; clustering the velocity vectors into at least one group within each section based on a defined criterion; generating trend lines representing each group of clustered velocity vectors within each section within the electrophysiological map. (2) The method of embodiment 1, wherein the cardiac tissue is the atrial cavity. (3) The method of embodiment 1, wherein the received electrophysiological map is a 3D map of local activation times associated with the cardiac tissue. (4) The method of embodiment 1, wherein the electrophysiological map is discretized into multiple isochronal sections. (5) The method of embodiment 4, wherein the electrophysiological map is discretized based on the direction of the velocity vector.

[0051] (6) The method of embodiment 1, wherein clustering further comprises applying a clustering algorithm to group the velocity vectors. (7) The method of embodiment 1, wherein the predefined criteria for clustering the velocity vectors includes at least one of a predefined proximity, a common direction, or a common propagation speed. (8) The method of embodiment 1, further comprising displaying the trend line on a display as an arrow within a 3D electrophysiological map. (9) The method of embodiment 1, wherein the processor is a component of an electrophysiological mapping system. (10) The method of embodiment 1, wherein the electrophysiological map is generated by an electrophysiological mapping system.

[0052] (11) A system for clustering wavefront signals in an electrophysiological map of cardiac tissue, comprising: A processor comprising a memory, receiving an electrophysiological map of the cardiac tissue representing the propagation of the wavefront signal as a plurality of velocity vectors; discretizing the received electrophysiological map into a plurality of sections; clustering the velocity vectors into at least one group within each section based on a defined criterion; generating trend lines representing each group of clustered velocity vectors within each section within the electrophysiological map. (12) The system described in embodiment 11, wherein the cardiac tissue is an atrial cavity. (13) The system described in embodiment 11, wherein the received electrophysiological map is a 3D map of local activation times associated with the cardiac tissue. (14) The system of embodiment 11, wherein the electrophysiological map is discretized into multiple isochronal sections. (15) The system of embodiment 14, wherein the electrophysiological map is discretized based on the direction of the velocity vector.

[0053] (16) The system of embodiment 11, wherein the processor is further configured to apply a clustering algorithm to cluster the velocity vectors. (17) The system of embodiment 11, wherein the predefined criteria for clustering the velocity vectors includes at least one of a predefined proximity, a common direction, or a common propagation speed. (18) The electrophysiological map is a 3D electrophysiological map; 12. The system of claim 11, wherein the processor is further configured to display the trend lines on a display as arrows within the 3D electrophysiological map. (19) The system of embodiment 11, wherein the processor is a component of an electrophysiological mapping system. (20) A non-transitory computer-readable recording medium storing program instructions for clustering wavefront signals in an electrophysiological map of cardiac tissue, the program instructions including: receiving an electrophysiological map of the cardiac tissue; representing the propagation of the wavefront signal as a plurality of velocity vectors; discretizing the received electrophysiological map into a plurality of sections; clustering the velocity vectors into at least one group within each section based on a predefined criterion; generating trend lines representing each group of clustered velocity vectors within each section within the electrophysiological map; and displaying the trend lines in the electrophysiological map on a display.

Claims

1. 1. A system for clustering wavefront signals in an electrophysiological map of cardiac tissue, comprising: A processor comprising a memory, receiving an electrophysiological map of the cardiac tissue representing the propagation of the wavefront signal as a plurality of velocity vectors; discretizing the received electrophysiological map into a plurality of sections; clustering the velocity vectors into at least one group within each section based on a defined criterion; generating trend lines representing each group of clustered velocity vectors within each section within the electrophysiological map.

2. The system of claim 1 , wherein the cardiac tissue is an atrial cavity.

3. The system described in claim 1, wherein the received electrophysiological map is a 3D map of local activation times associated with the cardiac tissue.

4. The system of claim 1 , wherein the electrophysiological map is discretized into a plurality of isochronal sections.

5. The system of claim 4 , wherein the electrophysiological map is discretized based on the direction of the velocity vector.

6. The system of claim 1 , wherein the processor is further configured to apply a clustering algorithm to cluster the velocity vectors.

7. The system of claim 1 , wherein the predefined criteria for clustering the velocity vectors includes at least one of a predefined proximity, a common direction, or a common propagation speed.

8. the electrophysiological map is a 3D electrophysiological map; The system of claim 1 , wherein the processor is further configured to display the trend lines on a display as arrows within the 3D electrophysiological map.

9. The system of claim 1 , wherein the processor is a component of an electrophysiological mapping system.

10. 1. A non-transitory computer-readable storage medium storing program instructions for clustering wavefront signals within an electrophysiological map of cardiac tissue, the program instructions comprising: receiving an electrophysiological map of the cardiac tissue; representing the propagation of the wavefront signal as a plurality of velocity vectors; discretizing the received electrophysiological map into a plurality of sections; clustering the velocity vectors into at least one group within each section based on a defined criterion; generating trend lines representing each group of clustered velocity vectors within each section within the electrophysiological map; and displaying the trend lines in the electrophysiological map on a display.

11. 1. A method of operating a system for clustering wavefront signals within an electrophysiological map of cardiac tissue, comprising: the system comprising a processor having a memory configured to receive an electrophysiological map of the cardiac tissue; the processor representing the propagation of the wavefront signal as a plurality of velocity vectors; the processor discretizing the received electrophysiological map into a plurality of sections; the processor clustering the velocity vectors into at least one group within each section based on a defined criterion; and generating a trend line representing each group of clustered velocity vectors within each section in the electrophysiological map.

12. The method of claim 11 , wherein the cardiac tissue is an atrial cavity.

13. A method of operating the system described in claim 11, wherein the received electrophysiological map is a 3D map of local activation times associated with the cardiac tissue.

14. The method of claim 11 , wherein the electrophysiological map is discretized into a plurality of isochronal sections.

15. The method of claim 14 , wherein the electrophysiological map is discretized based on the direction of the velocity vector.

16. A method of operating the system described in claim 11, wherein said clustering further comprises said processor applying a clustering algorithm to group said velocity vectors.

17. The method of claim 11 , wherein the predefined criteria for clustering the velocity vectors includes at least one of a predefined proximity, a common direction, or a common propagation speed.

18. A method of operating the system described in claim 11, further comprising the processor displaying the trend lines on a display as arrows within a 3D electrophysiological map.

19. The method of claim 11 , wherein the processor is a component of an electrophysiological mapping system.

20. The method of claim 11 , wherein the electrophysiological map is generated by an electrophysiological mapping system.

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