Systems and methods of far-field voltage mapping for scar severity estimation

Abstract

To provide a method and system for analyzing unipolar electrophysiological (EP) signals acquired by a multi-electrode catheter disposed within a ventricle of a patient's heart.SOLUTION: A method includes receiving a unipolar EP signal, extracting a unipolar far-field signal from the unipolar EP signal, and analyzing the extracted unipolar far-field signal to estimate a distribution of scar regions across a thickness of wall tissue of a cardiac chamber. A unipolar far-field EP map indicative of the scarred region is generated using the estimated distribution. The method further includes displaying the unipolar far-field EP map including the scarred region to a user. The system comprises a display device and a processor configured to perform the steps of the method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 674,324, filed July 23, 2024, which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION FIELD OF THE DISCLOSURE The present disclosure relates generally to electrophysiological (EP) signals, and specifically to methods for assessment of electrical propagation within the heart. [Background technology]

[0003] Estimation of non-local cardiac electrophysiological signals has previously been proposed in the patent literature. For example, U.S. Patent No. 11,464,437 describes a medical analysis system including at least one catheter inserted into a body part having a tissue surface, the catheter including sensing electrodes for contacting the tissue surface and receiving electrical signals from the tissue surface, and a processing circuit for receiving unipolar signals from each of a plurality of sensing electrodes, calculating combined far-field and mid-field signals based on summing and filtering each of the received unipolar signals received from at least one pair of sensing electrodes disposed around a point of interest, calculating the far-field signal as a weighted average of the received unipolar signals, weighted according to the distance of each of the sensing electrodes from the point of interest, and calculating and outputting a mid-field signal representing electrical activity beneath the tissue surface at the point of interest based on subtracting the calculated far-field signal from the calculated combined far-field and mid-field signals.

[0004] A more complete understanding of the present disclosure will be obtained from the following detailed description of the disclosed embodiments when read in conjunction with the drawings. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic, pictorial illustration of a catheter-based electrophysiology (EP) pacing, mapping and ablation system, according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic diagram illustrating a unipolar far-field EP map of cardiac scar severity in wall tissue of left ventricular tissue, according to an embodiment of the present disclosure. [Figure 3] 1 is a flow chart that schematically describes a method for generating a far-field unipolar EP map of cardiac scar severity, according to an embodiment of the present disclosure. [Figure 4] 1A-1C are diagrams illustrating a method for extracting the far field from a unipolar signal acquired using a multi-electrode catheter, according to an embodiment of the present disclosure. [Figure 5] 5 is a set of graphs of a unipolar signal acquired using the multi-electrode catheter of FIG. 4 and the respective extracted far-field signals, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006] overview Cardiac electrophysiological (EP) catheter mapping is a technique for generating three-dimensional EP maps of the inner surfaces of cardiac chamber wall tissue, such as unipolar activation voltage maps of the left ventricle (LV). Medical professionals can use EP maps to determine the precise source location of arrhythmias or to determine where to apply therapy (e.g., isolation) when performing medical procedures such as cardiac ablation.

[0007] In EP mapping of the inner surface of cardiac wall tissue, far-field cardiac EP signals are considered interference that degrades EP map quality. Far-field signals are presumed to arise due to electrical activity occurring further away from the catheter electrode. Far-field signals can distort or obscure local electrical activity, i.e., distort signals occurring in the immediate vicinity of the electrode.

[0008] However, in thick heart wall tissue, such as the LV wall, electricity conducts throughout different layers of the endocardium and myocardium. Some ventricular medical conditions require estimating electrical activity beneath the tissue surface. For example, after performing ablation (from the endocardial or epicardial side), residual EP conduction in the ablated ventricular tissue region may indicate persistent ventricular tachycardia (VT) due to insufficient ablation.

[0009] The regional cardiac EP mapping methods described above can identify electrically inactive (e.g., scar) tissue located primarily on the inner tissue surface (i.e., endocardial scar), but cannot easily assess the depth of the detected scar. Furthermore, in some cases, the inner surface may be electrically active with scar tissue located only underneath, e.g., deep in the myocardial wall tissue or on the epicardial surface, making regional mapping difficult to assess.

[0010] The poor EP diagnostic capabilities described above can sometimes be mitigated using cardiac MRI, which can provide tomographic assessment of thick ventricular wall tissue (e.g., distinguishing healthy or scar tissue across the thickness of the wall). However, MRI scans are expensive, have limited availability, and do not allow for rapid follow-up catheterization when necessary.

[0011] The embodiments of the present disclosure described herein provide a catheter EP mapping technique that uses far-field signals to estimate the distribution of scar regions in thick heart walls, such as the LV wall. The disclosed method uses the fact that the EP far-field signal drops off slightly differently for different scar types as the catheter electrode moves from healthy tissue toward a significant scar boundary or border line.

[0012] The disclosed technique estimates whether scar is present within the endocardial tissue or affects the endocardial and / or epicardial tissue. The technique provides a measure for estimating scar severity by comparing scar thickness to the overall thickness of the cardiac wall tissue. Finally, the technique provides a unipolar far-field EP map that describes the EP properties of the wall tissue in both the transverse and thickness directions.

[0013] In one embodiment, the disclosed method analyzes unipolar far-field signals extracted using the method described in commonly assigned U.S. Patent Application Publication No. 2023 / 0181087. The analysis of the extracted unipolar far-field signals aims to estimate the distribution of scar regions across (e.g., throughout) the thickness of the ventricular wall tissue.

[0014] If the endocardial scar does not exhibit significant far-field signal degradation toward the scar boundary line, the disclosed method infers that most of the tissue beneath the scar is healthy. If the endocardial scar is not apparent but significant far-field signal degradation occurs, the disclosed method infers that significant intracardiac or epicardial scar is present.

[0015] This method defines scar severity as the normalized ratio of scar width to total tissue width. The ratio is estimated based on (i) a mathematical model that analyzes the far-field signal and / or spatial derivatives, and (ii) an empirically derived correspondence between unipolar far-field EP signals and anatomical dissection or MRI imaging of actual scars.

[0016] Using the analysis of the far-field signal described above, the processor generates a unipolar far-field EP map that visualizes the distribution of scar regions. In one embodiment, the unipolar far-field EP map visually represents the different behavior of scar-associated peak-to-peak far-field potentials. In another embodiment, the unipolar far-field EP map visually represents the different behavior of scar-associated voltage gradients, such as the distribution of the maximum value of the negative derivative of the far-field signal, which varies differently for different scar depths. During development of the technology, the empirical correspondence described above will be used to validate the diagnostic capabilities of the disclosed far-field signal-based EP maps.

[0017] Finally, the disclosed method can cause the processor to delineate the boundary of the endocardial scar region and overlay the boundary line on the disclosed unipolar far-field EP map. Displaying such a boundary can facilitate visualization of the scar region along different depths in the heart wall tissue.

[0018] Clinicians using the disclosed unipolar far-field EP maps of scar severity can be rapidly guided (e.g., without relying on cardiac MRI diagnosis) to better clinical strategies for treating EP abnormal thick myocardial tissue, such as the LV.

[0019] System Description FIG. 1 is a schematic, pictorial illustration of a catheter-based electrophysiology (EP) pacing, mapping and ablation system 10 according to an embodiment of the present disclosure.

[0020] System 10 includes a planar multi-electrode EP mapping catheter 14 (e.g., an OPTRELL™ catheter manufactured by Biosense-Webster) that a physician 24 percutaneously inserts through a sheath through the patient's vascular system into the left ventricle of heart 12. The physician 24 brings a distal end assembly 28 of catheter 14 into contact with the heart wall to sense EP signals (e.g., unipolar signals) over a given area of ​​heart 12 of patient 23.

[0021] The catheter 14 includes a large-area flat distal tip assembly 28 configured to carry a plurality of electrodes 26 on a plurality of splines 22. The catheter 14 may include a position sensor 29 embedded in or near the distal tip assembly 28 on the shaft 46 of the catheter 14 for tracking the position and orientation of the distal tip 28. Optionally, and preferably, the position sensor 29 is a magnetic-based position sensor including three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0022] The magnetic-based position sensor 29 may be operated in conjunction with a location pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field within a defined working volume. The real-time position of the distal end assembly 28 of the catheter 14 may be tracked based on the magnetic field 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.

[0023] System 10 includes one or more electrode patches 38 positioned for skin contact with patient 23 to establish a position reference for location pads 25 and impedance-based tracking of electrodes 26 and to sense unipolar signals. For impedance-based tracking, current is directed to electrodes 26 and sensed at electrode skin patches 38, thereby 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.

[0024] Recorder 11 displays cardiac signals 21 (e.g., electrograms from a 12-lead ECG device acquired using body surface ECG electrodes 18). Recorder 11 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0025] Patient interface unit (PIU) 30 is an interface configured to establish electrical communication between the catheters, electrophysiology equipment, power supply, and workstation 55 to control the operation of system 10 and to receive EP signals from the catheters or apply pacing signals. The electrophysiology equipment of system 10 may include, for example, multiple catheters, location pads 25, body surface ECG electrodes 18, electrode patches 38, ablation energy generator 50, and recorder 11. Optionally and preferably, PIU 30 additionally includes processing capability to perform real-time calculations of catheter position and execute ECG calculations.

[0026] The workstation 55 includes a memory 57, a processor 56 unit with memory or loaded with appropriate operating software, and user interface functionality. The workstation 55 may optionally provide multiple functions, including (i) modeling the endocardial anatomical structure in three dimensions (3D) and rendering the model or anatomical map 20 for display on the display device 27, (ii) displaying activation sequences (or other data) compiled from the recorded cardiac signals 21 in a representative visual representation or image superimposed on the rendered anatomical map 20 on the display device 27, (iii) displaying the real-time positions and orientations of multiple catheters within the cardiac chambers, and (iv) displaying areas of interest, such as locations 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.

[0027] In some embodiments, processor 56 typically comprises a general-purpose computer that is programmed with software to perform the functions described herein. The software may be downloaded to the computer in electronic form, for example, over a network, or alternatively or additionally, may be provided and / or stored on non-transitory, tangible media, such as magnetic, optical, or electronic memory.

[0028] 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 monopolar or bipolar high-voltage direct current pulses used to produce irreversible electroporation (IRE), or a combination thereof.

[0029] For ablation, physician 24 similarly brings the distal end of an ablation catheter to the target site. One or more additional catheters may be inserted through the sheath. These may include a catheter for sensing intracardiac electrogram signals, a catheter dedicated to ablation, and / or a catheter dedicated to both EP mapping and ablation.

[0030] This configuration of system 10 is presented as an example to illustrate the particular problem addressed by embodiments of the present disclosure and to demonstrate the application of these embodiments in improving the performance of such systems. However, embodiments of the present disclosure are not limited to this particular exemplary system, and the principles described herein may be applied to other medical systems as well. For example, multi-electrode catheter types, such as a multi-arm OCTARAY™ catheter or basket catheter, may be used.

[0031] Far-field EP scar severity map 2 is a schematic pictorial rendering of a far-field unipolar EP map 200 of scar severity in left ventricular wall tissue, according to an embodiment of the present disclosure. Map 200 may be generated and displayed by processor 56 of system 10, for example.

[0032] In this example, scar region 210 includes endocardial tissue, scar region 220 includes endocardial tissue, and scar region 215 includes epicardial tissue. In some cases, scar regions 210, 215, and 220 partially overlap.

[0033] To distinguish between the scar regions 210, 215, and 220, the processor 56 may use a particular color or gray level (as shown) or may use a pattern (not shown) to indicate the scar regions with a particular graphical representation.

[0034] FIG. 2 further displays the boundary 245 of the endocardial scar region 210 as obtained from the local unipolar EP map using steps 310 and 324 of the method described below.

[0035] 2 may further show some of the locations, indicated at 212, where the catheter electrodes acquired the unipolar signal themselves. Processor 56 generated EP map 200 from the data points acquired at such locations using the method described in FIG. 3. Note that the graphical presentation of data points 212 on the map is not part of the disclosed algorithm. Thus, showing data points 212 is left to the user's discretion and is meant to provide the user with an additional, more coarse representation of the acquired data.

[0036] 2 illustrates the disclosed concept purely by way of example. In alternative embodiments, other suitable graphical representations can be constructed, such as graphical coding according to the region involved (e.g., only a single scar region 210, 215, or 220, or a pair of scar regions (e.g., 210, 215) or (215, 220), or if all three scar regions (210, 215, 220) are present around a given LV location).

[0037] A method of far-field EP mapping for scar severity estimation 3 is a flow chart that schematically describes a method for generating a far-field unipolar EP map of cardiac scar severity according to an embodiment of the present disclosure. The algorithm according to the presented embodiment executes a process that begins with a processor receiving unipolar signals acquired by a multi-electrode catheter, such as catheter 14 of FIG. 1, in step 302 of receiving a unipolar signal. The processor may be processor 56 or any processor of an offline computer. The signals may have been acquired some time previously and are uploaded from a memory, such as memory 57 or an offline memory.

[0038] In a unipolar far-field signal extraction step 304, processor 56 extracts a unipolar far-field signal from the unipolar signal received in step 302 using the method described in U.S. Patent Application Publication No. 2023 / 0181087.

[0039] In a generate local unipolar signal step 306, the processor uses the unipolar far-field signal to generate a clean local unipolar signal.

[0040] In the disclosed technique, the processor further stores the far field signals for use with the disclosed algorithms in a store far field signals step 320 .

[0041] Using the cleaned local unipolar signals in step 306, the processor generates local unipolar voltage maps in step 308 of local EP map generation.

[0042] In parallel, in analysis step 321, the processor analyzes the unipolar far-field signal stored in step 320 to estimate the location and depth of the scar. The processor relies on the far-field signal being slightly different (e.g., smaller) than the total signal at specific wall tissue locations as a function of location and depth, as seen in Figure 5 below. This method defines scar severity as the normalized ratio of scar width to total tissue width. The ratio is estimated based on (i) a mathematical model that analyzes the far-field signal and / or spatial derivatives, and (ii) an empirically derived correspondence between the unipolar far-field EP signal and anatomical dissection or MRI imaging of actual scars.

[0043] Using the analysis performed in step 321, the processor generates the far-field unipolar EP map 200 in far-field EP map generation step 322. The EP map may be a voltage map or a voltage gradient map, to name two examples.

[0044] In a border detection step 310, the processor detects the endocardial scar region border 345 on the local map.

[0045] The processor adds (e.g., superimposes) a boundary 345 onto the far-field unipolar EP map 200 in a scar boundary adding step 324. The resulting map is referred to in this disclosure as a "scar severity map."

[0046] Finally, the processor displays the combined map (ie, the scar severity map) to the user, for example on the display device 27.

[0047] The flowchart of Figure 3 is provided as an example. Additional steps may be included, such as displaying the local EP map to the user in step 308.

[0048] Unipolar far-field signal extraction One method for estimating and removing unipolar far-field signals is described in commonly assigned U.S. Patent Application Publication No. 2023 / 0181087. The algorithm disclosed in U.S. Patent Application Publication No. 2023 / 0181087 is inspired by the assumption that intracardiac unipolar far-field cardiac EP signals are similar but not identical across all multi-electrode EP mapping catheter electrodes. In the technique described in this publication, a mapping engine (e.g., a processor running the algorithm) weights catheter electrodes inversely proportional to their distance to identify a common signal (e.g., far-field signal) component across the electrodes. The mapping engine uses this common signal component to accurately reduce or cancel far-field interference. Reducing or canceling far-field interference by the mapping engine produces a cleaner near-field signal for improved local (e.g., near-field) cardiac mapping, as described in the above-referenced commonly assigned patent application.

[0049] The disclosed technique electrophysiologically estimates scar distribution in thick cardiac walls (e.g., including endocardial and epicardial portions) such as the LV using only far-field signals. The technique can utilize local EP maps to overlay endocardial scar region boundaries onto the disclosed unipolar far-field EP map.

[0050] 4 is a diagram illustrating a method for extracting the far field from unipolar signals acquired using a multi-electrode catheter, such as an OPTRELL™ catheter, according to an embodiment of the present disclosure. In step 402, the processor weights the electrodes surrounding a particular electrode inversely proportional to their distance from the particular electrode. In step 404, the processor multiplies the electrode far-field signals by their respective weights. A matrix of weighted far-field signal contributions for each electrode is generated (step 406), and the maximum signal is extracted (step 408). The processor correlates the maximum signal with the electrode signals (step 410) to provide a far-field estimate for each electrode of interest.

[0051] 5 is a set of graphs of a unipolar signal 502 acquired using a multi-electrode (such as an OPTRELL™ catheter) of FIG. 4 and a respective extracted far-field signal 504, according to an embodiment of the present disclosure. As can be seen, at some tissue locations, the extracted signals 504 are sensitive to scarring, and therefore the extracted far-field amplitude is smaller than the overall unipolar signal amplitude.

[0052] Clinical validation of far-field EP maps of scar severity One way to validate the EP map is to establish a correspondence between the measurement and analysis of far-field EP signals in the hearts of scarred animals maintained alive in the laboratory. A cohort of living animal hearts is prepared, for example, including three hearts, Heart A, Heart B, and Heart C, each with a different scar type (endocardial, epicardial, and myocardial). For each heart, the same three wall tissue regions with large, medium, and small relative tissue thicknesses are selected. A mapping catheter, such as the OPTRELL™ catheter described above, acquires reference signals from healthy animal hearts.

[0053] Subsequently, for each of the heart A, heart B, and heart C locations, a round endocardial, epicardial, or myocardial scar approximately 2 cm in diameter is ablated using multiple ablations (or any other technique) at varying transmural ratios. While symmetrically positioning the catheter over the scar, a 10-second signal recording is taken after a transmural ratio of 0.25 is reached. Ablation is applied until a transmural ratio of 0.5 is reached, after which a 10-second signal recording is taken. Ablation is applied until a transmural ratio of 0.75 is reached, after which a 10-second signal recording is taken. All acquired unipolar signals are processed for far-field signal extraction and analysis. [Example]

[0054] Example 1 The method involves receiving unipolar EP signals acquired by a multi-electrode catheter (14) positioned within a ventricle (12) of a patient's (23) heart. From these unipolar EP signals, unipolar far-field signals are extracted. The extracted unipolar far-field signals are analyzed to estimate the distribution of scar regions (210, 215, 220) across the thickness of the ventricle's wall tissue. This estimated distribution is used to generate a unipolar far-field EP map (200) indicative of the scar regions. The unipolar far-field EP map, including the scar regions, is then displayed to a user on a display device (27).

[0055] Example 2 2. The method of example 1, wherein analyzing the extracted unipolar far-field signal comprises analyzing one or more spatial derivatives of the far-field signal.

[0056] Example 3 The method of example 1 or example 2, wherein generating the unipolar far-field EP map includes showing the epicardial scar (215) on the unipolar far-field EP map.

[0057] Example 4 4. The method of any of Examples 1-3, wherein generating the unipolar far-field EP map comprises depicting intracardiac scar (220) on the unipolar far-field EP map.

[0058] Example 5 The method of any of Examples 1 to 4, wherein generating the unipolar far-field EP map includes calculating a ratio of scar thickness to total wall tissue thickness over the scar region, and displaying the unipolar far-field EP map includes displaying the ratio on the EP map.

[0059] Example 6 6. The method of any of Examples 1-5, comprising generating a local unipolar voltage map from the unipolar EP signal.

[0060] Example 7 7. The method of example 6, comprising detecting an endocardial scar boundary (245) in a local unipolar voltage map and overlaying the detected boundary on a unipolar far-field EP map.

[0061] Example 8 8. The method of any of Examples 1-7, comprising displaying a local unipolar voltage map to a user.

[0062] Example 9 9. The method of any one of Examples 1-8, wherein the multi-electrode catheter is one of a flat catheter and a multi-arm catheter.

[0063] Example 10 The system includes a display device (27) and a processor (56). The processor is configured to receive unipolar EP signals acquired by a multi-electrode catheter (14) positioned within a ventricle (12) of a patient's (23) heart. The processor extracts unipolar far-field signals from the unipolar EP signals and analyzes the extracted unipolar far-field signals to estimate the distribution of scar regions (210, 215, 220) across the thickness of the ventricle's wall tissue. Using the estimated distribution, the processor generates a unipolar far-field EP map (200) indicative of the scar regions and displays the unipolar far-field EP map, including the scar regions, to a user on the display device.

[0064] It will be understood that the embodiments described above 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.

[0065] [Embodiment] (1) receiving unipolar EP signals acquired by a multi-electrode catheter placed within a ventricle of a patient's heart; extracting a unipolar far-field signal from the unipolar EP signal; analyzing the extracted unipolar far-field signal to estimate a distribution of scar regions across a thickness of the ventricular wall tissue; generating a unipolar far-field EP map indicative of the scar region using the estimated distribution; and displaying the unipolar far-field EP map including the scar region to a user. (2) The method of embodiment 1, wherein analyzing the extracted unipolar far-field signal includes analyzing one or more spatial derivatives of the far-field signal. (3) The method of embodiment 1, wherein generating the unipolar far-field EP map includes showing epicardial scar on the unipolar far-field EP map. (4) The method of embodiment 1, wherein generating the unipolar far-field EP map includes showing intracardiac scar on the unipolar far-field EP map. (5) The method of embodiment 1, wherein generating the unipolar far-field EP map includes calculating a ratio of scar thickness to the total thickness of the wall tissue across the scar region, and displaying the unipolar far-field EP map includes displaying the ratio on the EP map.

[0066] (6) The method of embodiment 1, further comprising generating a local unipolar voltage map from the unipolar EP signal. (7) The method of embodiment 6, comprising detecting an endocardial scar boundary in the local unipolar voltage map and overlaying the detected boundary on the unipolar far-field EP map. (8) The method of embodiment 1, further comprising displaying the local unipolar voltage map to the user. (9) The method of embodiment 1, wherein the multi-electrode catheter is one of a flat catheter and a multi-arm catheter. (10) A system comprising: A display device; 1. A processor, comprising: receiving unipolar EP signals acquired by a multi-electrode catheter positioned within a ventricle of the patient's heart; extracting a unipolar far-field signal from the unipolar EP signal; analyzing the extracted unipolar far-field signal to estimate a distribution of scar regions across a thickness of the ventricular wall tissue; generating a unipolar far-field EP map indicative of the scar region using the estimated distribution; and displaying the unipolar far-field EP map including the scar region to a user on the display device.

[0067] (11) The system of embodiment 10, wherein analyzing the extracted unipolar far-field signal includes analyzing one or more spatial derivatives of the far-field signal. (12) The system of embodiment 10, wherein generating the unipolar far-field EP map includes showing epicardial scar on the unipolar far-field EP map. (13) The system of embodiment 10, wherein generating the unipolar far-field EP map includes showing intracardiac scar on the unipolar far-field EP map. (14) The system of embodiment 10, wherein generating the unipolar far-field EP map includes calculating a ratio of scar thickness to total thickness of the wall tissue across the scar region, and displaying the unipolar far-field EP map includes displaying the ratio on the EP map. (15) The system of embodiment 10, wherein the processor is further configured to generate a local unipolar voltage map from the unipolar EP signal.

[0068] (16) The system of embodiment 15, wherein the processor is further configured to detect an endocardial scar boundary in the local unipolar voltage map and overlay the detected boundary on the unipolar far-field EP map. (17) The system of embodiment 10, wherein the processor is further configured to display the local unipolar voltage map to the user. (18) The system of embodiment 10, wherein the multi-electrode catheter is one of a flat catheter and a multi-arm catheter.

Claims

1. 1. A system comprising: A display device; 1. A processor, comprising: receiving unipolar EP signals acquired by a multi-electrode catheter positioned within a ventricle of the patient's heart; extracting a unipolar far-field signal from the unipolar EP signal; analyzing the extracted unipolar far-field signal to estimate a distribution of scar regions across a thickness of the ventricular wall tissue; generating a unipolar far-field EP map indicative of the scar region using the estimated distribution; and displaying the unipolar far-field EP map including the scar region to a user on the display device.

2. The system of claim 1 , wherein analyzing the extracted unipolar far-field signal comprises analyzing one or more spatial derivatives of the far-field signal.

3. The system of claim 1 , wherein generating the unipolar far-field EP map includes showing an epicardial scar on the unipolar far-field EP map.

4. The system of claim 1 , wherein generating the unipolar far-field EP map comprises depicting intracardiac scar on the unipolar far-field EP map.

5. 2. The system of claim 1, wherein generating the unipolar far-field EP map comprises calculating a ratio of scar thickness to a total thickness of the wall tissue across the scar region, and displaying the unipolar far-field EP map comprises displaying the ratio on the EP map.

6. The system of claim 1 , wherein the processor is further configured to generate a local unipolar voltage map from the unipolar EP signal.

7. 7. The system of claim 6, wherein the processor is further configured to detect an endocardial scar boundary in the local unipolar voltage map and overlay the detected boundary on the unipolar far-field EP map.

8. The system of claim 1 , wherein the processor is further configured to display the local unipolar voltage map to the user.

9. The system of claim 1 , wherein the multi-electrode catheter is one of a flat catheter and a multi-arm catheter.

10. receiving unipolar EP signals acquired by a multi-electrode catheter positioned within a ventricle of the patient's heart; extracting a unipolar far-field signal from the unipolar EP signal; analyzing the extracted unipolar far-field signal to estimate a distribution of scar regions across a thickness of the ventricular wall tissue; generating a unipolar far-field EP map indicative of the scar region using the estimated distribution; and displaying the unipolar far-field EP map including the scar region to a user.

11. The method of claim 10 , wherein analyzing the extracted unipolar far-field signal comprises analyzing one or more spatial derivatives of the far-field signal.

12. The method of claim 10 , wherein generating the unipolar far-field EP map includes showing an epicardial scar on the unipolar far-field EP map.

13. The method of claim 10 , wherein generating the unipolar far-field EP map comprises depicting intracardiac scar on the unipolar far-field EP map.

14. 11. The method of claim 10, wherein generating the unipolar far-field EP map comprises calculating a ratio of scar thickness to a total thickness of the wall tissue over the scar region, and displaying the unipolar far-field EP map comprises displaying the ratio on the EP map.

15. The method of claim 10, comprising generating a local unipolar voltage map from the unipolar EP signal.

16. 16. The method of claim 15, comprising detecting an endocardial scar boundary in the local unipolar voltage map and overlaying the detected boundary on the unipolar far-field EP map.

17. The method of claim 10, comprising displaying the local unipolar voltage map to the user.

18. The method of claim 10 , wherein the multi-electrode catheter is one of a flat catheter and a multi-arm catheter.

Images