Method and system for analysis and presentation of connections between ablation points - Patent Application 20070122997

Abstract

1. A method, apparatus, and computer program product, the method comprising: obtaining coordinates of locations on a body part of a patient; determining at least one trajectory that includes at least some of the locations; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part that includes at least some of the locations and a visual indication of the connection between the locations; and, if the connection exceeds the threshold, providing a visual indication of the connection weights.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to medical applications, and more particularly to assessing and representing connections between ablation points. [Background technology]

[0002] Arrhythmias can be caused by problems with the heart's electrical conduction system, particularly electrical activity at one or more points or regions in the walls of the heart chambers. Atrial fibrillation is an arrhythmia characterized by disorganized signals that cause the atria (left and / or right atria) to contract in a very rapid, asynchronous heart rhythm.

[0003] A common treatment for atrial fibrillation, also known as A-fib, is ablation, which uses energy to create scars in one or more active areas of the heart wall to interrupt the erroneous electrical signals that contribute to the chaotic signal and restore a typical heartbeat. Ablation can be performed using one or more types of energy to create the scar, including, but not limited to, radiofrequency (RF), pulsed fields (sometimes called PFA or irreversible electroporation (IRE)), focused laser, ultrasound, heat, etc. [Brief explanation of the drawings]

[0004] A more complete understanding of the present disclosure will be obtained from the following detailed description of the embodiments of the present disclosure when read in conjunction with the drawings. [Figure 1] 1 is a schematic, pictorial illustration of a catheter-based electrophysiological (EP) mapping and ablation system, according to some exemplary embodiments of the present disclosure; [Figure 2A] 1 is a schematic illustration of a heart undergoing ablation, according to some exemplary embodiments of the present invention; [Figure 2B]1 is a schematic illustration of a user examining a heart having multiple sites where ablation has been applied, according to some exemplary embodiments of the present disclosure; [Figure 3A] This shows the effect of larger distances in three-dimensional space that appear shorter in projection onto a two-dimensional plane. [Figure 3B] This shows the effect of larger distances in three-dimensional space that appear shorter in projection onto a two-dimensional plane. [Figure 3C] 3C illustrates points as in FIG. 3B with connecting lines added, according to some embodiments of the present disclosure. [Figure 4] 1 is a flow diagram of steps in a method for determining and displaying ablation sites and connections therebetween, according to some exemplary embodiments of the present disclosure. [Figure 5A] 1 shows an example of a segment connecting ablation locations as created by a conventional solution. [Figure 5B] 1 shows an example of a segment connecting ablation locations as created by a conventional solution. [Figure 5C] 1 illustrates examples of connection segments created by existing solutions and some exemplary embodiments of the present disclosure. [Figure 5D] 1 illustrates examples of connection segments created by existing solutions and some exemplary embodiments of the present disclosure. [Figure 5E] 1 illustrates examples of connection segments created by existing solutions and some exemplary embodiments of the present disclosure. [Figure 5F] 1 illustrates examples of connection segments created by existing solutions and some exemplary embodiments of the present disclosure. [Figure 6] 1 illustrates an image of the heart as displayed on a display device, along with ablation points and estimated trajectories, according to some embodiments of the present disclosure. [Figure 7] FIG. 1 is a schematic block diagram of a computing platform for determining and indicating connections between ablation points that exceed a predetermined threshold, according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0005] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known circuits, control logic, and details of computer program instructions for conventional algorithms and processes have not been shown in detail in order to avoid unnecessarily obscuring the present invention.

[0006] Software programming code embodying aspects of the present invention is typically maintained in permanent storage, such as a computer-readable medium. In a client-server environment, such software programming code may be stored on either the client or the server. The software programming code may be embodied in any of a variety of known media for use with data processing systems, including, but not limited to, magnetic and optical storage devices, such as disk drives, magnetic tape, compact discs (CDs), and digital video discs (DVDs), as well as computer instruction signals embodied in a transmission medium, with or without a carrier wave upon which the signals are modulated. For example, the transmission medium may include a communications network, such as the Internet. Additionally, while the present invention may be embodied in computer software, the functionality required to carry out the present invention may alternatively be embodied, in part or entirely, using hardware components, such as application-specific integrated circuits or other hardware, or some combination of hardware components and software.

[0007] Overview It is known that atrial fibrillation can be caused by abnormal conduction pathways originating from muscle bundles extending from the atria to the pulmonary veins.

[0008] Cardiac ablation is a procedure in which cardiac tissue on the inner surface of a heart chamber is locally heated and ablated to alleviate cardiac dysfunction, such as atrial fibrillation. For example, ablation can create electrical pulmonary vein isolation, thereby restoring sinus rhythm.

[0009] When a physician, typically a cardiologist, performs an ablation therapy, the physician typically creates an ablation lesion by applying energy to cardiac tissue using an ablation electrode positioned at the distal end of a catheter. The ablation electrode contacts tissue within a cardiac chamber at multiple discrete ablation sites along a predetermined trajectory. Depending on the ablation area and the desired outcome, the defined trajectory may be open, i.e., a line with a beginning and an end point, or may form a closed loop.

[0010] The cardiologist can monitor the procedure by observing the position of the catheter tip in an image of the heart on a display, which can be detected, for example, by a catheter position tracking system or an imaging system.

[0011] If a cardiologist creates adjacent ablation lesions that are too far apart, the resulting gap may not completely eliminate the parasitic electrical pathway of, for example, cardiac activation waves, and cardiac dysfunction may not be fully alleviated.

[0012] During the procedure, for each site where an ablation is applied, the three-dimensional (3D) location and, optionally, additional characteristics such as a measure of the quality of the ablation, the temperature at which the ablation was created, the thickness of the heart wall, etc. The sites may be displayed to the physician during and / or after surgery on a display device showing an image of the heart or a portion thereof.

[0013] Currently, physicians can visually estimate whether an ablation location forms a required trajectory (sometimes called an "ablation path" or "ablation line"), whether it is closed or open, and whether the distance between any two consecutive sites along the trajectory is small enough to eliminate parasitic electrical pathways. However, visual estimation may not be accurate enough. Additionally, projecting a 3D ablation location onto a two-dimensional (2D) display may distort distances, invalidating reliable determinations.

[0014] Simple methods, such as tracking the creation time of ablation sites and determining the distance between any two consecutively created ablations, if available, may also not provide a complete solution, since a physician may revisit a particular region after ablating another region and create another ablation between two previously created ablations. Additionally, a physician may create ablations in two or more separate regions with large distances between the regions, but this does not pose a problem.

[0015] Several computational solutions have been proposed for determining trajectories and distances, particularly for identifying distances within the same region that exceed a threshold, however, such solutions are not satisfactory.

[0016] Accordingly, embodiments of the present disclosure provide systems and methods for more accurately determining, and optionally visualizing, the trajectories on which ablation points are located and the connections between associated cardiac ablation sites. In some embodiments, a processor of a cardiac mapping and ablation system may receive coordinates of multiple ablation sites on the surface of the heart. The processor may then apply a unique combination of computational methods to determine connectivity between the ablation sites. The processor may then trigger visualization of some or all of the connections. For example, each connection may be marked with a color, width, pattern, or additional indicator representing its size or size range. For example, connections longer than a certain threshold may be shown in a more prominent manner than shorter connections. In other embodiments, only connections with distances exceeding a threshold may be shown.

[0017] Using the disclosed solution, the physician is provided with a clear real-time visual display that highlights the trajectory and at least indicates where the connections between ablation points may be of poor quality. Using such a display, the physician can revisit problem locations and successfully complete the ablation procedure.

[0018] System Description Refer to FIG. 1 , which illustrates an exemplary catheter-based electrophysiology mapping and ablation system 10. The system 10 includes multiple catheters that can be percutaneously inserted by a physician 24 through the vascular system of a patient 23 and into a chamber or vasculature of a heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location in the heart 12. One or more catheters can then be inserted through the delivery sheath catheter to reach the desired location within the heart 12. The multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters dedicated to both sensing and ablation. An exemplary catheter 14 configured to sense IEGMs is illustrated herein. The physician 24 can position a distal tip 28 of the catheter 14 in contact with the heart wall to sense a target site in the heart 12. For ablation, the physician 24 can similarly position a distal end of an ablation catheter in contact with a target site for tissue ablation.

[0019] Catheter 14 is an exemplary catheter that includes one, and preferably multiple, electrodes 26 optionally distributed across multiple splines 22 at distal tip 28 and configured to sense IEGM signals. Catheter 14 may additionally include a position sensor 29 embedded in or near distal tip 28 for tracking the position and orientation of distal tip 28. Optionally and preferably, position sensor 29 is a magnetic-based position sensor that includes three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0020] The magnetic-based position sensor 29 may operate in conjunction with a location pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field within a predetermined working volume. The real-time position of the distal tip 28 of the catheter 14 may be tracked based on the magnetic fields generated by the location pad 25 and sensed by the magnetic-based position sensor 29. Details of magnetic-based position sensing technology are described in U.S. Patent Nos. 5,5391,199; 5,443,489; 5,558,091; 6,172,499; 6,239,724; 6,332,089; 6,484,118; 6,618,612; 6,690,963; 6,788,967; and 6,892,091.

[0021] Additionally or alternatively, system 10 may include one or more electrode patches 38 positioned for skin contact on patient 23 to establish a position reference for location pads 25 and impedance-based tracking of electrodes 26. For impedance-based tracking, current is directed to electrodes 26 and sensed at electrode skin patches 38, allowing the position of each electrode to be triangulated via electrode patches 38. Details of impedance-based position tracking techniques are described in U.S. Patent Nos. 7,536,218; 7,756,576; 7,848,787; 7,869,865; and 8,456,182.

[0022] Recorder 11 may record and display electrograms 21 captured by ECG electrodes 18 on the body surface and IEGMs captured by electrodes 26 on catheter 14. Recorder 11 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0023] The system 10 may include an ablation energy generator 50 adapted to deliver ablation energy to one or more electrodes at the distal tip of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radiofrequency (RF) energy or pulsed-field ablation (PFA) energy, including unipolar or bipolar high-voltage DC pulses, such as may be used to effect irreversible electroporation (IRE), or a combination thereof.

[0024] A patient interface unit (PIU) 30 may be configured to establish electrical communication between the catheters, other electrophysiological equipment, a power source, and a workstation 55 that controls the operation of the system 10. The electrophysiological equipment of the system 10 may include, for example, multiple catheters, location pads 25, body surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 additionally includes processing capability to implement real-time calculations of catheter position and perform ECG calculations.

[0025] The workstation 55 includes a processor unit having memory, a memory or storage device having appropriate operating software stored therein, and user interface functionality. The workstation 55 may provide multiple functions, optionally including: (1) modeling the endocardial anatomical structure in three dimensions (3D) and rendering the model or anatomical map 20 for display on the display device 27; (2) displaying on the display device 27 activation sequences (or other data) compiled from recorded electrograms 21 with representative visual indicia or images superimposed on the rendered anatomical map 20; (3) displaying real-time locations and orientations of multiple catheters within the cardiac chambers; and (4) displaying sites of interest, such as where ablation energy has been applied, on the display device 27. One commercially available product embodying elements of the system 10 is available as the CARTO™ 3 system, available from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0026] In the following description, the terms "site," "ablation site," "location," "ablation location," and the like are used interchangeably and should be broadly interpreted to refer to the location where ablation is applied.

[0027] In the following description, the terms "connection" and "distance" may be used interchangeably and should be interpreted broadly to refer to a segment connecting two ablation sites. Depending on the context, the terms "distance," "distance length," or "distance weight" may be interpreted as Euclidean distance, distance along the body tissue, or any of the above in combination with additional factors as detailed below.

[0028] 2A, there is shown a schematic diagram of a heart 12 undergoing ablation, according to an embodiment of the present invention. Ablation electrodes at the distal end 28 of the catheter 14 contact the heart chamber at multiple ablation sites 200 to induce localized necrosis of cardiac tissue. Lesions are formed at each ablation site 200.

[0029] Using position tracking of a position sensor at distal end 28 or an imaging system as described above, a recorder such as recorder 11 of FIG. 1 can record the location of ablation site 200 as physician 24 uses the ablation electrodes to form multiple lesions on the surface of the thermal cavity. The location of ablation site 200 can be displayed to a user such as physician 24 in real time, stored, and presented at a later time point after the procedure.

[0030] Electrophysiology (EP) mapping electrodes near the distal end 28 of the catheter 14 or a separate catheter may be used to monitor changes in the cardiac signal measured by one or more mapping electrodes in response to the ablation treatment, as described above.

[0031] Referring now to FIG. 2B, there is shown a schematic diagram of a user 204, which may or may not be the same as the physician 24, examining an image of the heart 12 having annotations related to the ablation site 200 as displayed on a display device 27, according to some embodiments of the present disclosure.

[0032] FIG. 2B shows an expanded view of the ablation region of FIG. 2A at inset 208 of ablation site 200 after processing by a processor, such as the processor of workstation 55.

[0033] For some ablation sites 200, the nearest ablation site may be more than a threshold away and therefore may be unacceptable because parasitic electrical pathways for cardiac activation waves may not be eliminated. The threshold may have a default value or may be set by the user 204. The threshold may also depend on the particular location within the heart 12. Connections with unacceptable distances or distance weights may be highlighted to the user 204 with a thick line 216.

[0034] It is understood that some connections, such as those along line 220, may be longer than visually apparent and are therefore shown in bold.

[0035] The diagrams shown in Figures 2A and 2B are for conceptual clarity only and are not intended to limit embodiments of the present invention. Although the ablation sites in Figures 2A and 2B are shown as open trajectories, the present disclosure is equally applicable to showing closed trajectories, such as those created to isolate pulmonary veins.

[0036] Note that in Figures 2A and 2B, for clarity, the lesions at multiple ablation sites 200 are depicted as being circular and the lesion diameters are depicted as being approximately the same. In some circumstances, one or more ablation sites 200 may be amorphous rather than circular, and the diameters of the ablation sites 200 may differ from one another depending, for example, on the ablation parameters (e.g., ablation time or ablation signal power) applied to each ablation site. In some embodiments, the distance measured between ablation sites 200 does not take into account the site diameter. For example, the distance may be calculated between ablation site centers or centers of mass. In other embodiments, the distance measured between ablation sites 200 may depend on the site diameter. For example, for the same ablation site center point, the distance between larger diameter lesions may be smaller than the distance between smaller diameter lesions.

[0037] In some embodiments, the processor of workstation 55 may also scale the distance weights between ablation sites by a scaling factor that depends on the ablation quality (also referred to as the ablation index) or other factors of one or both of the ablation sites, as described in more detail below. As a result, low-quality ablation sites are interpreted as being further away from other sites than high-quality sites.

[0038] In some applications, such as medical applications and particularly atrial ablation applications, the distance may be calculated over the relevant body tissue rather than as a Euclidean distance, which may generally increase the distance.

[0039] 3A and 3B, the effect of making longer distances appear shorter in a projection onto a flat surface, such as the display surface of a visual display device, is shown.

[0040] 3A shows three 3D points: point 300 with coordinates (0,0,0), point 304 with coordinates (1,5,1), and point 308 with coordinates (5,0,1). The distances are therefore 300-304: sqrt(27), 304-308: sqrt(42), and 308-300: sqrt(26), i.e., the longest distance is between points 304 and 308, and the shortest distance is between 300 and 308.

[0041] 3B, the coordinates become 300'(0,0), 304'(1,1), and 308'(5,1), and therefore the corresponding distances are 300'-304': sqrt(2), 304'-308': sqrt(16), and 308'-300': sqrt(26). Thus, the longer distance appears to be between points 300' and 308', and the shortest is between 300' and 304', which does not reflect the relationship between the actual 3D distances.

[0042] Therefore, highlighting distances that exceed the threshold may be particularly important, as distances that exceed the threshold may not be perceived as such by a user, such as a physician examining an image of the heart 12, and may therefore lead to suboptimal ablation results.

[0043] Referring now to FIG. 3C, points as in FIG. 3B are shown with completed connecting lines according to some embodiments of the present disclosure.

[0044] Connecting lines between points that may represent ablation sites are supplemented with scales, and the distance between any two consecutive scales is constant for the entire image. Thus, segment 312 connecting points 300' and 304' and segment 320 connecting points 300' and 308' each contain four scales because the distances are approximately the same length (sqrt(26) and sqrt(27)), so rounding the distances results in the same number of scales. It will be appreciated that segment 316 connecting 304' and 308', which is sqrt(42) in length, has seven scales and therefore appears shorter in the projection than segment 320, but represents a longer distance than the other segments.

[0045] As mentioned above, the distance can be calculated as a Euclidean distance or across the associated body tissues, so the number of scales can be increased further as the distance can be much longer than a Euclidean distance.

[0046] It is understood that the length of a connection segment, also referred to as a connection, may additionally or alternatively be represented by the color, shading, pattern, or another characteristic of the segment. For example, a longer connection may be indicated by a darker shading, a denser pattern, etc. However, the scale also provides a quantitative measure of the connection that allows the user to easily assess the distance. It is also understood that two or more display methods, such as scale and / or pattern and / or color and / or shading and / or width, may be used simultaneously.

[0047] In some embodiments, all connected segments may be displayed so that the physician can see the complete ablation trajectory, with connections with higher weights being displayed in a more prominent manner. In other embodiments, segments may be displayed and captured only if the distance between the ablation site and the nearest ablation site exceeds a threshold, allowing the physician to easily detect areas where more ablation sites may be needed without unnecessarily cluttering the image.

[0048] In further embodiments, connections between ablation sites may also be displayed, for example, in Wide Area Circumferential Catheter (WACA) ablation cases where the ablation surrounds two pulmonary veins.

[0049] Referring now to FIG. 4, there is shown a flow diagram of steps in a method for determining and displaying trajectories connecting ablation sites and the connections therebetween, according to some embodiments of the present disclosure.

[0050] In step 400, coordinates of the ablation site may be obtained. The data may be obtained from the ablation system during the ablation procedure, or may be retrieved from a storage device or the like during or after the ablation procedure. The ablation site may be obtained intraoperatively when the physician checks whether additional sites need to be ablated, or at a later time when it is desired to inspect the ablation results.

[0051] The ablation site may optionally be received as a 3D point along with additional parameters, such as, for example, an ablation index indicating the ablation quality, a timestamp when the ablation was created, and the like.

[0052] Ablation sites may be considered as nodes in the graph, and a virtual segment connecting two ablation sites may be interpreted as an edge in the graph. Edges may be unidirectional or bidirectional; in the present disclosure, edges may be bidirectional, i.e., not associated with a particular direction.

[0053] Each edge may have a weight, which may be equal to the length of the segment.

[0054] It is understood that the circles in the graph relate to closed orbits connecting multiple nodes, and not necessarily to geometric circles.

[0055] In step 402, one or more trajectories may be determined, each including at least some of the locations, with each such trajectory representing an ablation action designed to electrically isolate a region of the heart. It is understood that the ablation trajectories may be open, as in the case of roof ablation, or closed, as in the case of circumferential ablation.

[0056] Step 402 may include step 404, in which the ablation sites may be clustered. Clustering may generally refer to dividing nodes in a graph into groups, where the distance between nodes in the same group is less than the distance between nodes assigned to different clusters. Thus, ablation sites may be considered as nodes in the graph, and the connection between two ablation sites is an edge. Thus, each cluster may represent ablation sites performed to electrically isolate a particular region of the heart, such as one or a pair of pulmonary veins.

[0057] Clustering may be performed using any currently known method or any method that becomes known in the future, such as, but not limited to, K-means clustering, mean-shift clustering, Density-Based Spatial Clustering of Applications with Noise (DBSCAN), Expectation-Maximization (EM) clustering using Gaussian Mixture Models (GMM), affinity propagation, agglomerative clustering, BIRCH, mini-batch K-means, OPTICS, spectral clustering, or others.

[0058] In some embodiments, multiple clustering methods may be applied and the clustering used may be selected by majority vote.

[0059] Clustering may use the distance between sites as a connection weight, and the distance between two ablation points may be calculated as Euclidean distance, but may also be calculated as distance along the cardiac tissue. Additionally or alternatively, the connection weight may take additional factors into account. For example, the distance between ablation sites may be scaled by a scaling factor that also incorporates the size of the ablation sites and the quality (also called the ablation index) of one or both of the ablation sites. As a result, low-quality ablation sites may be interpreted as being further away from other sites than high-quality sites. Additional factors may include one or more anatomical factors, such as the temperature at which the lesion was created at the ablation site and the thickness of the heart wall in the region of the lesion.

[0060] Step 402 may include step 408 in which connecting segments, also called edges, may be determined between ablation sites within each cluster.

[0061] In some embodiments, the connected segments may form a spanning tree, in particular a minimum spanning tree. In a graph, a minimum spanning tree includes all nodes in the graph and a number of edges equal to the number of nodes minus one, such that no cycles are formed. A minimum spanning tree has a minimum total edge weight, where the weight of each edge is as detailed above and the total edge weight is the sum of the weights of all edges in the tree. In some embodiments, one or more locations in a cluster may be excluded, e.g., not be part of the spanning tree if the total weight without this location is significantly lower than that with this location.

[0062] A minimum spanning tree can be found using any currently known algorithm or algorithm that becomes known in the future, such as, but not limited to, Boruvka's algorithm, Prim's algorithm, Kruskal's algorithm, or others.

[0063] In step 410, it may be determined whether additional segments can be added that form a closed trajectory when added to the spanning tree. It is understood that in further iterations, segments may be added to the top of the spanning tree, and segments may have been added in earlier iterations. However, edges that close the trajectory may not always meet predetermined conditions and thus may be excluded from being added, for example, in roof ablation, where the edge connecting the first and last location sites may be too long.

[0064] In some embodiments, step 410 may include activating an algorithm such as the Warshall-Floyd method that, for each pair of nodes in the current graph, calculates the total weight of the path between the nodes, where the path consists of edges that exist in the spanning tree or edges that were previously added. Because the graph is a tree, it is understood that a single path exists between any two nodes before any edges are added. For each such pair of nodes, a distance, such as the Euclidean distance, is also calculated.

[0065] It may then be determined whether the pair of nodes with the best tradeoff between path weight and distance also meets one or more predetermined conditions, as described in more detail below. The tradeoff may aim to select the edge with the smallest weight such that the total weight in the graph of paths connecting the edge nodes is maximized. Intuitively, the algorithm aims to find the shortest edges that generate the largest circuit.

[0066] It will be appreciated that the weight calculations detailed above may be applicable to calculating edge weights when determining minimum spanning trees and path weights, as well as to calculating connection weights between two ablation locations that are not already connected by an edge.

[0067] If such a segment exists (“yes”), the segment may be added to the graph to form a closed orbit in step 412. Execution may then return to step 410 to search for additional segments.

[0068] It is understood that the algorithm is not simple, as any three or more nodes and the paths connecting them can be closed into a loop. However, connecting too few points may result in finding local circuits that do not cover the closed orbit of the ablation site, while connecting too many points may introduce a noisy image.

[0069] In some situations, for example, in roof ablation, the edge between nodes that offers the best tradeoff may not meet certain conditions, e.g., its weight, Euclidean distance, or distance along the body tissue may exceed certain thresholds. Again, intuitively, this may be the case when the ablation location forms an elongated shape and is not intended to form a circuit.

[0070] Thus, if there are no segments to be added or if the maximum number of edge addition iterations has been performed, e.g., 5-20 iterations, such as 10 iterations, execution may continue at step 414 in selecting the next cluster and proceeding as detailed above for the next cluster. If it is determined at step 411 that there are no other clusters, execution may proceed to step 416, as described in more detail below.

[0071] 5A and 5B, two examples of ablation locations and the connections between them as created by conventional solutions are shown. FIG. 5A shows a graph 500 that includes two local circuits 504 and 508, which may be confusing to a physician because they are two small circuits that represent a closed orbit. Additionally, graph 500 does not show the connections between locations 512 and 516, and between locations 524 and 528.

[0072] Similarly, graph 532 in Figure 5B shows a cut between locations 548 and 549, as well as another cut as shown in region 560. Additionally, segment 541 unnecessarily closes an unwanted circuit, which can further disrupt the flow.

[0073] 5C-5F, examples of calculating connectivity are shown, according to some example embodiments of the present disclosure. It is understood that the examples of FIGS. 5C-5F consider only the Euclidean distance between points as the weight of connectivity. Some locations in any of FIGS. 5C-5F may appear to overlap or touch each other partially or completely, and such locations are considered to be pairwise connected to each other.

[0074] Figure 5C shows graph 564 with the same node locations as Figure 5A above after computing the minimum spanning tree. It can be seen that a graph that is a tree does not contain closed circuits, thus eliminating local circuits in graph 500. Additionally, graph 564 does not have any disconnected nodes or groups of nodes.

[0075] Figure 5D shows graph 576 with the same node locations as Figure 5C after running the Warshall-Floyd method and selecting edges 580 to form a closed orbit, resulting in a large circuit with no discontinuities and no local loops.

[0076] Figure 5E shows graph 584 with the same ablation locations as Figure 5B above, after computing the minimum spanning tree. It can be seen that a graph that is a tree does not contain closed circuits, thus eliminating local circuits in graph 500. Additionally, graph 584 does not have any disconnected nodes or groups of nodes.

[0077] Figure 5F shows graph 593 with the same ablation locations as Figure 5E after running the Warshall-Floyd method and selecting the edges to add as described above. Thus, edges 594 and 596 have been added, closing two circuits: one circuit containing both locations 588 and 590, and the other circuit containing either 588 or 590 and node 597. The result is a large circuit with no discontinuities and no local loops.

[0078] Several morphological considerations may be taken into account when determining which edges to add, for example, the circularity of a circle may be taken into account, for example, by estimating the standard deviation of the location from the center of mass of the created shape and prioritizing circuits with a low standard deviation.

[0079] In some exemplary embodiments, the presence or absence of one or more edges connecting the ablation sites may be subject to user consideration. Thus, the user may mark particular edges or particular pairs of ablation sites as connected and / or mark other pairs of edges or ablation sites as not having a connection. These indications may be used as constraints in the creation of trajectories, i.e., the presence of an edge may be enforced or eliminated if so indicated by the user.

[0080] In step 416, it may be determined which segments connecting ablation sites are longer than a threshold value, such as 3 mm to 10 mm, e.g., 4 mm, indicating that the ablation points connected by the segments may be too far apart to ensure electrical isolation. Note that this threshold may be different from, e.g., shorter than, the threshold used as a condition in step 410 to determine which connecting edges should be added. For example, if no segments longer than 6 mm are added in step 410, the threshold used in step 416 may be applicable to the added segments and indicate segments longer than 4 mm. It should be noted that conventional methods show multiple long segments, such as segment 520 in FIG. 5A and segments 536, 540, 544, 541, and 543 in FIG. 5B, where some segments, such as 540 and 541, are clearly unnecessary, while the present disclosure only shows segments 536 and 543 as being too long, as seen in FIG. 5F.

[0081] In step 420 , an image of the heart or a portion thereof may be displayed, for example, as image 20 on display device 27 or as shown in image 208 .

[0082] In step 424, the segments identified in step 416 that are at least longer than the threshold may be shown on the image. However, other segments that form a closed trajectory may also be shown similarly. Additionally, the length of the displayed segments may be visually indicated by tick marks, patterns, colors, shading, widths, etc., or a combination of two or more of the above, as detailed above. In other embodiments, all segments may be shown on the display.

[0083] Referring now to FIG. 6, there is shown an image 600 of the heart as displayed on a display device, along with an ablation point and two estimated trajectories 604 and 608, according to some embodiments of the present disclosure.

[0084] It should be understood that some ablation points, such as 602, are not part of any such circle.

[0085] It should also be appreciated that some segments, such as 612, 616, and 620, are shown with marks indicating that they may be longer or have a higher weight than the threshold (although this may not appear to be the case due to the 2D projection) and should be further examined.

[0086] Different circuits such as 604 and 608 may or may not be displayed in different color schemes to more visually distinguish them.

[0087] Referring now to FIG. 7, there is shown a block diagram of a computing platform 700 for determining whether connectivity between ablation points exceeds a predetermined threshold, according to some exemplary embodiments of the present disclosure.

[0088] It will be appreciated that computing platform 700 may be embedded within workstation 55, but may also be a stand-alone computing platform, or may be embedded elsewhere and in operative communication with workstation 55.

[0089] Computing platform 700 may be implemented as one or more computing platforms that may be operatively connected to one another. For example, one or more remote computing platforms may be implemented, such as on a cloud computer. Other computing platforms may be part of an associated organizational computer network. In other embodiments, all functionality may be provided by one or more computing platforms that are all part of the organizational network.

[0090] Computing platform 700 may include one or more processors 704, which may or may not be located on the same computing platform, and which may be one or more central processing units (CPUs), microprocessors, electronic circuits, integrated circuits (ICs), etc. Processor 704 may be configured to provide the required functionality by, for example, loading into memory and activating software modules stored in storage device 712, described in more detail below.

[0091] The computing platform 700 may include a communications module 708 for communicating with other devices or computing platforms, e.g., retrieving information from a catheter procedure controller, storing data to or receiving data from a remote storage device, etc. The communications module 708 may be adapted to interface with any communications channel, such as a local area network (LAN), a wide area network (WAN), a cellular network, etc., and to use any associated communications protocol.

[0092] Computing platform 700 may include a storage device 712, such as a hard disk drive, flash disk, random access memory (RAM), memory chips, etc. In some example embodiments, storage device 712 may hold program code operable to cause processor 704 to perform operations associated with any of the modules listed below or steps of the method of Figure 4 above. The program code may include one or more executable units, such as functions, libraries, stand-alone programs, etc., adapted to execute instructions, as detailed below.

[0093] Alternatively or additionally, the provided instructions may be stored on a non-transitory, tangible computer-readable medium, such as magnetic, optical, or electronic memory.

[0094] The storage device 712 may include an I / O module 716 for rendering to a user displays to be displayed on the display device 27, such as a map of the heart, ablation points, and a display of the distances therebetween. The I / O module 716 may also be operable to receive command and operating parameters from a user.

[0095] The storage device 712 may include a communication module 720 for sending and receiving data to and from other systems, such as the ablation system, external storage devices, etc.

[0096] The storage device 712 may include a clustering module 724, which may include one or more modules for clustering sites, such as, but not limited to, a K-means clustering module 726, a mean-shift clustering module 728, an EM clustering module using GMM 732, a density-based clustering module 736, or others.

[0097] The storage device 712 may include an initial connection segment calculation module 740, which may include one or more modules for calculating segments connecting ablation sites, such as, but not limited to, a minimum spanning tree calculation module 744 (which may be implemented in multiple ways by multiple algorithms), or others.

[0098] The storage device 712 may comprise a circuit closure module 748, which may comprise one or more modules for determining how to close the spanning tree into a closed orbit.

[0099] The circuit closure module 748 may comprise a module for calculating the weight of a path between any two nodes in the tree, such as, for example, but not limited to, a Warshall-Floyd implementation module 752, or other.

[0100] The circuit closure module 748 may include a distance calculation module 756 for calculating distances or weights between nodes representing ablation sites and / or for determining whether one or more of the edge weights exceed a threshold.

[0101] The circuit closure module 748 may include an edge selection module 760 for selecting edges to be added to the initial segment based on a trade-off between, for example, the weight of the path connecting two locations as calculated by the Warshall-Floyd implementation module 752 (or another algorithm) and the distance between the locations as calculated by the distance calculation module 756. The circuit closure module 748 may also determine that no edges are added such that one or more trajectories are not closed.

[0102] The storage device 712 may include a visual display calculation module 764 for determining how to visually display the connections. In some embodiments, all connection segments may be shown in the image, and those connection segments whose length exceeds a threshold may be marked accordingly. In other embodiments, only connection segments whose length exceeds a threshold may be marked. The markings may take various forms, in particular, tick marks may be added at regular distances, where the distance between two tick marks actually indicates a regular distance or a regular weight, and the number of tick marks along a segment indicates its length. Alternative or additional marking methods may also be used, such as patterns, widths, colors, shading, etc.

[0103] It is understood that the steps and modules disclosed above may be in addition to the software, hardware, firmware, or other modules required to operate the catheter, display the catheterization process, generate cardiac maps, etc. Further details regarding methods and systems can be found, for example, in U.S. Patent Nos. 8,676,305 and 9,629,567, which are incorporated herein by reference in their entirety for any purpose.

[0104] The present invention may be a system, a method, and / or a computer program product, which may include a computer-readable storage medium having computer-readable program instructions for causing a processor to perform aspects of the present invention.

[0105] A computer-readable storage medium may be a tangible device capable of holding and storing instructions for use by an instruction execution device. The computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD), memory sticks, floppy disks, mechanically encoded devices such as punch cards or ridge-in-groove structures with instructions recorded thereon, and any suitable combination of the foregoing. As used herein, computer-readable storage medium should not be construed as being a signal that is itself ephemeral, such as an electric wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse passing through a fiber optic cable), or an electrical signal transmitted through a current line.

[0106] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device or to an external computer or external storage device over a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions to a computer-readable storage medium within the respective computing / processing device for storage.

[0107] Computer-readable program instructions for carrying out operations of the present invention may be either assembler instructions, instruction set architecture instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, such as Java, C, C++, Python, etc. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute the computer-readable program instructions by utilizing state information from the computer-readable program instructions to individualize the electronic circuitry to carry out aspects of the present invention.

[0108] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0109] These computer-readable program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing device to generate a machine, such that the instructions, when executed by the processor of the computer or other programmable data processing device, create means for performing the functions / acts specified in the flowchart and / or block diagram blocks. These computer-readable program instructions can also be stored on a computer-readable storage medium that can cause a computer, programmable data processing apparatus, and / or other device to function in a particular manner, such that the computer-readable storage medium on which the instructions are stored includes an article of manufacture containing instructions that implement aspects of the functions / acts specified in the flowchart and / or block diagram blocks.

[0110] The computer-readable program instructions may be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to generate a computer-implemented process, such that the instructions executing on the computer, other programmable apparatus, or other device perform the functions / acts defined in the flowchart and / or block diagram blocks.

[0111] The flowcharts and block diagrams in the figures illustrate the structure, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of instructions, including one or more executable instructions for implementing the depicted logical function(s). In some alternative implementations, the functions shown in the blocks may occur out of the order shown in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flow diagrams, and combinations of blocks in the block diagrams and / or flow diagrams, may be implemented by a dedicated hardware-based system that performs the specified function or operation, or may be operated or executed by a combination of dedicated hardware and computer instructions. [Example]

[0112] Example 1 1. A method comprising: obtaining coordinates of locations on a patient's body part; determining at least one trajectory that includes at least some of the locations; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part that includes at least some of the locations and a visual indication of the connection between the locations; and, if the connection exceeds the threshold, providing a visual indication of the connection weights.

[0113] Example 2 2. The method of example 1, wherein determining at least one trajectory comprises clustering the locations to form at least one cluster; and determining a tree within each cluster.

[0114] Example 3 3. The method of example 2, wherein the tree is a minimum spanning tree.

[0115] Example 4 3. The method of example 2, further comprising determining at least one segment connecting locations in the cluster; and adding the segment to the tree such that the tree forms at least one closed orbit.

[0116] Example 5 5. The method of example 4, wherein determining at least one segment forming at least one closed orbit uses the Warshall-Floyd method.

[0117] Example 6 5. The method of example 4, wherein determining at least one segment forming at least one closed orbit uses a trade-off between a weight of a path connecting two locations in the tree and a distance between the two locations.

[0118] Example 7 The method of example 1, wherein the location is the location of an ablation site within the patient's body.

[0119] Example 8 2. The method of example 1, wherein at least one trajectory encircles two pulmonary veins of the patient.

[0120] Example 9 The method of example 1, wherein the visual indication includes tick marks, and the number of tick marks along the segment connecting at least two locations indicates the length of the segment.

[0121] Example 10 The method of example 1, wherein connectivity is quantified as Euclidean distance.

[0122] Example 11 The method of example 1, wherein the connection is quantified as a distance along the patient's tissue.

[0123] Example 12 2. The method of example 1, wherein the at least one trajectory is at least one closed trajectory.

[0124] Example 13 The method of example 1, wherein determining at least one trajectory or distance also uses at least one factor to assess connectivity, and the at least one factor is selected from the group consisting of ablation size, ablation index, temperature at the ablated location, and anatomical characteristics.

[0125] Example 14 The method of Example 13, wherein the anatomical feature is the thickness of the heart wall at the site of injury.

[0126] Example 15 2. The method of example 1, wherein at least one trajectory includes at least one segment indicated by a user as being present.

[0127] Example 16 2. The method of example 1, wherein at least one trajectory does not include at least one segment indicated by the user as not present.

[0128] Example 17 1. A computerized device having a processor coupled to a memory unit, the processor adapted to perform the steps of obtaining coordinates of locations in a body part of a patient; determining at least one trajectory including at least some of the locations; determining whether a connection between at least two locations connected along the trajectory exceeds a threshold; providing a visual representation of the body part including at least some of the locations and a visual indication of the connection between the locations; and, if the connection exceeds the threshold, providing a visual indication of the connection weights.

[0129] Example 18 18. The computerized apparatus of example 17, wherein the processor is adapted to perform steps for determining at least one trajectory, the steps including: clustering the locations to form at least one cluster; and determining a minimum spanning tree within each cluster.

[0130] Example 19 19. The computerized apparatus of example 18, wherein the processor is adapted to determine at least one segment connecting locations in the cluster and add the segment to the tree such that the tree forms at least one closed orbit.

[0131] Example 20 1. A computer program product comprising a non-transitory computer-readable medium bearing program instructions that, when read by a processor, cause the processor to: obtain coordinates of locations in a body part of a patient; determine at least one trajectory that includes at least some of the locations; determine whether a connection between at least two locations connected along the trajectory exceeds a threshold; provide a visual representation of the body part that includes at least some of the locations and a visual indication of the connection between the locations; and, if the connection exceeds the threshold, provide a visual indication of the connection weights.

[0132] Although the embodiments described herein primarily address cardiac diagnostic applications, the methods and systems described herein may also be used in other medical applications.

[0133] It will be understood that the above-described embodiments are given by way of example, and that the present disclosure is not limited to what is particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon reading the foregoing description.

[0134] [Embodiment] (1) A method comprising: obtaining coordinates of a location on a body part of a patient; determining at least one trajectory that includes at least a portion of the location; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part including at least some of the locations and a visual indication of connections between the locations; providing a visual indication of the connection weight if the connection exceeds the threshold. (2) determining the at least one trajectory clustering the locations to form at least one cluster; determining a tree within each cluster. (3) The method of embodiment 2, wherein the tree is a minimum spanning tree. (4) determining at least one segment connecting locations within the cluster; and 3. The method of claim 2, further comprising adding the segments to the tree such that the tree forms at least one closed orbit. (5) The method of embodiment 4, wherein determining the at least one segment forming at least one closed orbit uses the Warshall-Floyd method.

[0135] (6) The method of embodiment 4, wherein determining the at least one segment forming at least one closed orbit uses a trade-off between the weight of a path connecting two locations in the tree and the distance between the two locations. (7) The method of embodiment 1, wherein the location is the location of an ablation site within the patient's body. (8) The method of embodiment 1, wherein the at least one trajectory surrounds two pulmonary veins of the patient. (9) The method of embodiment 1, wherein the visual indication includes a scale, and the number of scale marks along the segment connecting the at least two locations indicates the length of the segment. (10) The method of embodiment 1, wherein the connectivity is quantified as Euclidean distance.

[0136] (11) The method of embodiment 1, wherein the connection is quantified as a distance along the tissue of the patient. (12) The method of embodiment 1, wherein the at least one trajectory is a closed trajectory. (13) The method of embodiment 1, wherein determining the at least one trajectory or the distance also uses at least one factor to evaluate connectivity, and the at least one factor is selected from the group consisting of ablation size, ablation index, temperature at the ablated location, and anatomical characteristics. (14) The method of embodiment 13, wherein the anatomical feature is the thickness of the heart wall at the site of injury. (15) The method of embodiment 1, wherein the at least one trajectory includes at least one segment indicated by the user as being present.

[0137] (16) The method of embodiment 1, wherein the at least one trajectory does not include at least one segment indicated by the user as not present. (17) A computerized device having a processor coupled to a memory unit, the processor comprising: obtaining coordinates of a location on a body part of a patient; determining at least one trajectory that includes at least a portion of the location; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part, including at least some of the locations and a visual indication of connections between the locations; and providing a visual indication of the connection weight if the connection exceeds the threshold. (18) The processor: clustering the locations to form at least one cluster; determining a minimum spanning tree within each cluster. (19) The computerized apparatus of claim 18, wherein the processor is adapted to determine at least one segment connecting locations in the cluster and add the segment to the tree such that the tree forms at least one closed orbit. (20) A computer program product comprising a non-transitory computer-readable medium bearing program instructions, the instructions, when read by a processor, causing the processor to: obtaining coordinates of a location on a body part of a patient; determining at least one trajectory that includes at least a portion of the location; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part including at least some of the locations and a visual indication of connections between the locations; and providing a visual indication of the connection weight if the connection exceeds the threshold.

Claims

1. 1. A computerized apparatus having a processor coupled to a memory unit, the processor comprising: obtaining coordinates of a location on a body part of a patient; determining at least one trajectory that includes at least a portion of the location; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part, including at least some of the locations and a visual indication of connections between the locations; and providing a visual indication of the connection weight if the connection exceeds the threshold.

2. the processor: clustering the locations to form at least one cluster; and determining a minimum spanning tree within each cluster.

3. 3. The computerized apparatus of claim 2, wherein the processor is adapted to determine at least one segment connecting locations in the cluster and add the segment to the tree such that the tree forms at least one closed orbit.

4. 1. A computer program product comprising a non-transitory computer-readable medium bearing program instructions, the instructions, when read by a processor, causing the processor to: obtaining coordinates of a location on a body part of a patient; determining at least one trajectory that includes at least a portion of the location; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part including at least some of the locations and a visual indication of connections between the locations; and providing a visual indication of the connection weight if the connection exceeds the threshold.

5. 1. A method comprising: obtaining coordinates of a location on a body part of a patient; determining at least one trajectory that includes at least a portion of the location; determining whether a connection between at least two locations connected along the at least one trajectory exceeds a threshold; providing a visual representation of the body part including at least some of the locations and a visual indication of connections between the locations; providing a visual indication of the connection weight if the connection exceeds the threshold.

6. determining the at least one trajectory clustering the locations to form at least one cluster; and determining a tree within each cluster.

7. The method of claim 6 , wherein the tree is a minimum spanning tree.

8. determining at least one segment connecting locations within the cluster; The method of claim 6 further comprising adding the segments to the tree such that the tree forms at least one closed orbit.

9. The method of claim 8 , wherein determining the at least one segment forming at least one closed orbit uses a Warshall-Floyd method.

10. 9. The method of claim 8, wherein determining the at least one segment forming at least one closed orbit uses a trade-off between a weight of a path connecting two locations in a tree and a distance between the two locations.

11. The method of claim 5 , wherein the location is the location of an ablation site within the patient's body.

12. The method of claim 5 , wherein the at least one trajectory encircles two pulmonary veins of the patient.

13. The method of claim 5 , wherein the visual indication includes a scale, and the number of scale marks along a segment connecting the at least two locations indicates a length of the segment.

14. The method of claim 5 , wherein the connectivity is quantified as a Euclidean distance.

15. The method of claim 5 , wherein the connection is quantified as a distance along the patient's tissue.

16. The method of claim 5 , wherein the at least one trajectory is a closed trajectory.

17. 6. The method of claim 5, wherein determining the at least one trajectory or the distance also uses at least one factor to evaluate connectivity, and the at least one factor is selected from the group consisting of an ablation size, an ablation index, a temperature at the ablated location, and an anatomical feature.

18. 18. The method of claim 17, wherein the anatomical feature is the thickness of the heart wall at the location of the injury.

19. The method of claim 5 , wherein the at least one trajectory includes at least one segment indicated by a user as being present.

20. The method of claim 5 , wherein the at least one trajectory does not include at least one segment indicated by a user as not present.

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