Mesh catheter system and methods with high-resolution electrodes configured for mapping, pacing, and ablation

Abstract

A catheter utilizes a distal electrode array configured for quantification of endocardial or epicardial propagation velocity, with electrodes defining approximately equilateral triangles, such that the calculated velocity can be approximated regardless of the wave front direction. The distal electrode array can also include resilient splines carrying the electrodes such that the splines can deform to ensure contact between the electrodes and the heart tissue. Additionally, the electrodes of the distal electrode array can be individually addressable. Bipolar ablation lines or boxes can also be implemented using two parallel catheters at the endocardium and at the epicardium. Certain configurations include one or more distal electrode arrays of sufficient size to span an entire ventricular tachycardia (VT) circuit. The catheter may also be configured to detect block lines by pacing from edge pacing electrodes of the distal electrode array, and / or to detect fiber orientation by pacing from several edge pacing electrodes.

Description

MESH CATHETER SYSTEM AND METHODS WITH HIGH-RESOLUTIONELECTRODES CONFIGURED FOR MAPPING, PACING, AND ABLATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 721,328 filed 15 November 2024, which is hereby incorporated by reference in its entirety.FIELD OF INVENTION

[0002] The present invention relates generally to apparatuses, systems, and methods for measuring bioelectrical signals of the body; and more specifically, but not by way of limitation, to apparatuses, systems, and methods for measuring electrical field potentials of a patient’s heart.BACKGROUND

[0003] Ventricular arrhythmias can lead to sudden death. United States Patents No. 5,546,951, and No. 6,690,963 to Haim, and PCT application WO 96 / 05768, all of which are incorporated herein by reference, address methods for sensing an electrical property of heart tissue, like local activation time, as a function of precise location in the heart. Data are acquired with catheters that have electrical and location sensors.

[0004] Methods of creating maps of the electrical activity of the heart based on the collected data are addressed in United States Patents No. 6,226,542 and No. 6,301,496, both issued to Reisfeld, which are incorporated by reference. Local activation time in the endocardium in each location point can be inferred due to the time dependent behavior of the electrical excitation waves. A direction of propagation may be represented by an activation vector, and the trajectory of points on the heart surface may be used to infer motion characteristics like contractility of the tissue.

[0005] As disclosed in United States Patent No. 5,738,096 to Haim, which is incorporated herein by reference, maps depicting motion characteristics may be constructed when the trajectory information is sampled. Mapping the activation front and the conduction properties can help a physician to identify and diagnose abnormalities, such as ventricular and atrial tachycardia and fibrillation, which can result from areas with impaired electrical propagation300431716.1 - 1 -in the heart tissue. Proarrhythmogenic regions in the heart’s conduction may be localized by abnormal propagation properties. Example of defects in the heart’s conduction include reentrant circuits. Once defects are located by mapping data, it may be treated by ablated or other treatment to restore the normal function of the heart insofar as possible. The electrical activity at a point in the heart can be analyzed by advancing a catheter, that contains electrical sensors near its distal tip, to the location point in the heart. Multiple-electrode catheter systems have been developed to simultaneously detect and measure electrical activity, such as local activation time at multiple sampled points in the heart, for example, as in United States Patent Application Publication No. US 20190015007 to Rottmann.SUMMARY

[0006] This disclosure describes a catheter system and methods for mapping of electrical activity in the heart and performing ablation. At least some configurations of the present catheter system include an electrode array (or mapping array or mapping assembly) that is configured for quantification of endocardial or epicardial propagation velocity. In order to quantify conduction properties, the electrical field potentials at a localized electrode can be measured by two electrodes that are positioned at a point of interest, with a known distance between the two electrodes, and the time difference between the electrodes detected as the activation time of these two electrode positions.

[0007] The propagation velocity between two electrodes may be defined as the distance / time; but doing so assumes that the excitation wave travels parallel to a line between these two electrodes. However, the direction of propagation is typically unknown in catheters previously used for clinical electrophysiological studies, for example, Lasso or PentaRay catheters. In contrast, the present disclosure includes catheters with multiple electrodes arranged in substantially equilateral triangles, such that calculated velocity can be determined more accurately regardless of the wave front direction.

[0008] Furthermore, the electrodes of the present catheter systems can be coupled by splines that can be configured to deform (e.g., elastically and / or resiliently) to allow the splines (and corresponding positions of the electrodes) to conform to the curvature of a surface of a given portion, such that adjacent electrodes contact the heart tissue. The plurality of electrodes, combined with the conformability of the splines, permits ablation line or box isolation without moving the catheter, for example, (1) by activating ablation electrodes within one line for an ablation line procedure or (2) by activating ablation electrodes along different lines or curves.300431716.1 - 2 -By way of further example, the present catheter systems can be used to define bipolar ablation lines by using two parallel catheters at the endocardium and at the epicardium, respectively.

[0009] The plurality of electrodes in the present catheter systems may also be deployed to cover or otherwise span an entire ventricular tachycardia circuit with its VT isthmus, multiple entry and exit sites and outer loops or multiple reentries or focal activities in the atrium or the ventricle with high resolution over several cycle lengths, and may identify and visualize, e.g., the VT-isthmus, entrance- and exit-site locations of different cycles for ablation target points. Additionally, the present catheter systems can also be configured and / or deployed to detect block lines, for example, by pacing from the edge pacing electrodes of the catheter system and by combining the detected block lines from each pacing site, and fiber orientation with high resolution by pacing from several edge pacing electrodes. Finally, the novel catheter system may be used as a modular combined catheter, e.g., with three combined catheters that are configured map an entire ventricle with high resolution without moving the catheter.

[0010] Additionally, systems disclosed herein can include a multi-electrode assembly of a catheter. For instance, a catheter body can have a proximal end and a distal end. An arrangement of electrodes can be operable to couple to a distal portion of the catheter body. The arrangement of electrodes can have an angular spacing between adjacent electrodes being between 130 degrees and 145 degrees. In some cases, the angular spacing between adjacent electrodes can be between 137 degrees and 138 degrees (e.g., 137.5 degrees). Furthermore, a system for determining cardiac tissue characteristics can include an electrode array operable to connect to a distal portion of a catheter body. The electrode array can include a plurality of electrodes arranged to include at least an approximately equilateral triangular mesh. Also, computer-readable media storing executable instructions can, upon being executed by one or more processors, cause the system to receive electrical signals from the plurality of electrodes, and / or calculate an endocardial propagation velocity vector or a epicardial velocity vector for the approximately equilateral triangular mesh based at least in part on the received signals. The arrangement of the electrodes in the approximately equilateral triangular mesh can ensure that the accuracy of the calculated propagation velocity is substantially invariant with respect to the direction of a wavefront propagating across the tissue.

[0011] Moreover, some aspects of the presently disclosed technology can include a catheter system comprising a plurality of electrodes coupled together by a plurality of splines. At least one of the plurality of splines can be configured to deform in an elastic or resilient manner to conform to a curvature of a tissue surface. Additionally, the conforming to the curvature of the tissue surface can facilitate contact between heart tissue and two or more adjacent electrodes300431716.1 - 3 -of the plurality of electrodes. The plurality of electrodes can include a multi-array electrode system formed by a plurality of electrode arrays. Also, an apparatus can include a catheter having a distal end, and a plurality of distal electrode arrays carried by the catheter at the distal end. The plurality of distal electrode arrays can collectively define a combined array, where the combined array is configured for deployment as a single integral unit. By way of example, the catheter can be a single inner catheter of the apparatus. Additionally, the multiple distal electrode arrays can be considered a plurality of distal electrode arrays. Moreover, the plurality of distal electrode arrays can be carried by the catheter, disposed on the single inner catheter, and / or coupled to the single inner catheter.

[0012] In some examples, a method can include calculating a plurality of first positions of an earliest activation time and a plurality of second positions of a latest activation time for a plurality of connected block lines using an isochronal map generated by a plurality of electrodes positioned at heart tissue. The method can also include confirming an existence of a continuous signal path based on whether, using a plurality of predetermined time steps, the plurality of earliest activations are < 4 millimeters apart from each other. The earliest and latest activation time points can be considered to belong to one wave if the start and end points of the rotational wave are closer together than 2.5 mm. Moreover, the plurality of predetermined time steps can be between 4-6 ms (e.g., 5 ms). The method can also include determining whether the earliest activation time occurs at a plurality of different locations, and selecting, based on the determining, a closest point to a block line of the plurality of connected block lines by using a nearest neighbor method.

[0013] In some scenarios, a method can include determining a plurality of local activation times (LAT)s based on an electrical signal generated by a plurality of electrodes of an electrode array of a catheter, and calculating a reentry pathway size by using a number of LATs of the plurality of LATs included in a reentry pathway, the calculating of the reentry pathway can use, as quality criteria: the reentry pathway being detected at four or more activation points (e.g., or nine or more activation points), and / or at least one of a width dimension or a length dimension of the reentry pathway being in millimeters (e.g., being less than 10 mm). Additionally, or alternatively, a method can include generating, using electrical signals from a plurality of electrodes of an electrode array of a catheter, simultaneous mappings of electrode array recordings in different atrial regions. The method can also include calculating temporal behaviors of one or more parameters of the simultaneous mappings. The one or more parameters can include at least one of a slow conduction zone, a rotational source, or a focal300431716.1 - 4 -source. Furthermore, the method can include causing a visualization of the temporal behaviors to be presented at console of a computing device.

[0014] The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically; two items that are “coupled” may be unitary with each other. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. The term “substantially” is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. In any disclosed configuration, the term “substantially” may be substituted with “within [a percentage] of’ what is specified, where the percentage includes .1, 1, 5, and 10 percent.

[0015] Further, an apparatus or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described.

[0016] The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), and “include” (and any form of include, such as “includes” and “including”) are open-ended linking verbs. As a result, an apparatus that “comprises,” “has,” or “includes” one or more elements possesses those one or more elements, but is not limited to possessing only those elements. Likewise, a method that “comprises,” “has,” or “includes” one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.

[0017] Any configuration of any of the apparatuses, systems, and methods can consist of or consist essentially of - rather than comprise / include / have - any of the described steps, elements, and / or features. Thus, in any of the claims, the term “consisting of’ or “consisting essentially of’ can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open- ended linking verb.

[0018] The feature or features of one configuration may be applied to other configurations, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of the configurations.

[0019] Some details associated with the configurations described above and others are described below.300431716.1 - 5 -BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers. The figures are drawn to scale (unless otherwise noted), meaning the sizes of the depicted elements are accurate relative to each other for at least the configuration depicted in the figures.

[0021] FIG. 1 is an illustration of the use of one example of the present catheter systems for evaluating electrical activity in a heart of a patient.

[0022] FIG. 2A is a schematic view of an example of a distal electrode array, with electrodes and splines, of the present catheters.

[0023] FIG. 2B is a diagram of electrode arrangement angles between electrodes in the golden section for the electrode array of FIG. 2 A.

[0024] FIG. 3 is a schematic diagram of a layout of an example of the present catheter systems having an outer catheter and an inner catheter with a distal electrode array of FIG. 2 A with multiple splines.

[0025] FIGs. 4A-4C illustrate the sequential deployment of the distal electrode array of FIG. 2 A from the catheter system of FIG. 3.

[0026] FIG. 5A illustrates a schematic diagram (left) of a layout of another example of a distal electrode array with equilateral triangles between the electrodes and (right) the calculation of endocardial or epicardial propagation velocity vector on the triangular mesh of that distal electrode array.

[0027] FIG. 5B is a schematic of the catheter with electrode locations measured in millimeters.

[0028] FIGs. 6A-6C illustrates the deployment and deformation of another example of the present distal electrode arrays to conform to the curvature of a surface of a portion of heat tissue.

[0029] FIGs. 7A-1-7B-2 illustrate different ablation strategies, including ablation line and box isolation which may be performed with the invention without moving the catheter, but by activating ablation electrodes (open circles) within one line (FIG. 7A-1) or by activating ablation electrodes (open circles) along multiple lines (FIG. 7B-1), as well as schematics of the resulting scar sizes of the ablation line (FIG. 7A-2) and box isolation (FIG. 7B-2).300431716.1 - 6 -

[0030] FIG. 8 illustrates another example of the present distal electrode arrays (left) with dimensions that can allow the array to span an entire ventricular tachycardia circuit with its VT isthmus, multiple entry and exit sites and outer loops, and schematics (right) of VT circuits over time showing variations of the VT isthmus, entrance, and exit site locations. These identified locations may be used to improve and / or optimize ablation strategy.. Because of the complete coverage of the catheter and mapping with high resolution over several cycle lengths, the catheter system is able to also identify dynamic behavior of VT circuits over time and to localize VT-isthmus, entrance- and exit site locations of different cycles.

[0031] FIGs. 9A-9C illustrate conceptually the detection of block lines which are wave front and frequency dependent by pacing from the five edge pacing electrodes of a distal electrode array of the present catheter systems, and by combining the detected block lines from each pacing site.

[0032] FIG. 10 illustrates conceptually the detection of fiber orientation with high resolution by pacing from several edge pacing electrodes of one of the distal electrode arrays.

[0033] FIG. 11 illustrates conceptually a method of bipolar ablation lines or bipolar box isolation lines between the endocardium and epicardium by using two distal electrode arrays fo the present catheters at the endocardium and at the epicardium.

[0034] FIG. 12 illustrates an example of the present multi-array catheter systems, e.g., with three (3) distal electrode arrays each having 30 electrodes (for 90 total electrodes) for mapping an entire ventricle (e.g., with high resolution).

[0035] FIG. 13A illustrates a flow diagram of an example of an algorithm for prefiltering and detection of reentry trajectory.

[0036] FIGs. 13B-13J illustrate various examples of details associated with certain implementations of the algorithm of FIG. 13 A.

[0037] FIGs. 14A-14B illustrate a comparison of manual and automatic annotations of reentries and U-turns. Complete reentry with > 270-degree rotations and U-turn detection with > 180-degree rotation but < 360-degree rotation.

[0038] FIGs. 15A-1-15B-2 illustrate a comparison of a traditional phase algorithm (FIGs. 15A-1, 15A-2) and the algorithm illustrated in FIG. 13 (FIGs. 15B-1, 15B-2).

[0039] FIGs. 16A, 16B, and 16C illustrate simultaneous reentry mapping over time in neighboring atrial regions with 2 or more synchronous mapping plaques.300431716.1 - 7 -DETAILED DESCRIPTION

[0040] Turning to the drawings, reference is made to Figure 1, which illustrates the use of one example of the present catheter systems for diagnostics in the heart.

[0041] The system compromises an outer catheter or sheath and an inner catheter which is inserted by an operator through the patient’s vascular system such that a distal electrode array is deployed via the inner catheter into a chamber of the heart. An operator brings the distal electrode array into contact with the heart, i.e., at or near an ablation target point. Activation time maps may be visualized accordingly to various methods, for example, as disclosed in United States Patents No. 6,226,542, No. 6,301,496, and No. 6,892,091, which are incorporated by reference in their respective entireties.

[0042] The present catheter systems may include a computer, for example having memory and a processor configured to execute instructions (e.g., from the memory) to implement various steps and algorithms to implement the functions described in this disclosure. Portions of the system in other drawing figures are shown as comprising a number of separate functional blocks, however these blocks are not necessarily separate physical units, but rather may represent, i.e., different computer tasks or data objects in a memory that is accessible to the processors. The tasks may be carried out in software, which runs on a single processor or multiple processors. Software and / or firmware may be provided to the processor via a media such like a CD-ROM or non-volatile memory. Additionally or alternatively, the system may compromise a digital signal processor or hard-wired logic.

[0043] Areas of heart tissue with abnormal conduction, e.g., as detected by analyzing electrical activation maps, may be ablated by a physician by applying thermal energy based on radiofrequency electrical current through one or more electrodes to the heart tissue. Such energy heats the tissue typically above 50°C such that the tissue permanently loses its electrical excitability. A successful ablation procedure creates non-conduction lesions, which disrupt the abnormal electrical pathway(s) that were causing the arrhythmia. The systems and principles of described herein can be applied for different heart chambers and different heart arrhythmias.

[0044] In the depicted configuration, the catheter system compromises a handle with controls to enable the operator to steer, position and orient the distal end of the catheter as desired. The distal electrode array

[0045] The distal portion of the catheter includes a distal electrode array. The array and system can be configured to determine position, e.g., by deriving information from signals received by the electrodes and / or the inclusion of dedicated position sensors that provide300431716.1 - 8 -signals to a processor, which may be located in a console accessible by a user. For example, the electrodes of the array have known relative positional relationships and known distances between one another that can be used to correlate time and other signal characteristics to infer information from signals from the electrodes. In some configurations, the system includes a positioning subsystem, for example with a magnetic position tracking arrangement that determines the position and orientation of the catheter by sensing generated magnetic fields in a working volume. Examples of such a positioning subsystem are in United States Patents No. 7,756,576 and No. 7,536,218, which are incorporated by reference in their respective entireties.

[0046] Electrical signals can be conveyed from the heart via electrodes of the distal electrode array at or near the distal tip of the inner catheter, for example, via wiring or other conductors to the console. Pacing or other signals may also be conveyed to the heart tissue. For measuring location and orientation coordinates, signals may also be sent and / or received bia body surface electrodes. Electrodes may measure tissue impedance at the ablation site as described in United States Patent No. 7,536,218 to Govari, which is incorporated by reference in its entirety.

[0047] Typically, one or more ablation power generators are included in a console. The catheter may conduct ablation energy to the heart using any known ablation technique, e.g., radiofrequency energy, ultrasound energy, laser energy. Examples of such methods are disclosed in United States Patents No. 6,814,733, No. 6,997,924, and No. 7,156,819, which are incorporated by reference in their respective entireties.

[0048] As shown in Figure 1, the catheter can be coupled to a console for enabling, observing, and regulating the functions of the catheter. The console shown includes a processor with appropriate signal processing circuits and is coupled to drive a monitor. The signal processing circuits are configured to receive, amplify, filter and digitalize signals from the catheter, including signals generated by the above described sensors and several location sensing electrodes. A positioning subsystem is configured to compute based on the digitalized signals the position and orientation of the catheter.

[0049] The system can also include additional components such as an electrocardiogram (ECG) monitor, which receives signals from one or more body surface electrodes, a reference position sensor and a reference patch, or an internal placed catheter in a fixed position to the heart. The system may also receive image data from an external imaging unit such as MRI for generating and visualizing images.300431716.1 - 9 -Construction

[0050] Reference is made to FIG. 3 which depicts a schematic view of a portion of an example of the present catheters.

[0051] In one example construction of the catheter body compromises an outer wall made of polyurethane or Pebax (polyether block amide). The outer wall can compromise an embedded braided mesh of stainless steel or the like, as is known in the art, to increase torsional stiffness of the catheter body so that when a control handle is rotated, the distal end of the catheter body rotates in a corresponding manner.

[0052] The length of the catheter body may vary, but in some configurations may range from about 190 cm to about 120 cm, and more preferable is about 110 cm.

[0053] The outer diameter of the inner catheter body may also vary, but in some configurations is no more than about or equal to a nominal diameter of 8 French (e.g., about or equal to a nominal diameter of 7 French). The thickness of the outer wall of the inner catheter may also vary, but in some configurations is thin enough for central lumen to accommodate puller wires, lead wires, and sensor cables (e.g., and other components).

[0054] In some configurations, an inner surface of the outer wall of the inner catheter is lined with a stiffening liner to provide improved torsional stability. An example of a catheter body construction that may be suitable for use in connection with the present systems is disclosed in United States Patent No. 6,064,905, which is incorporated by reference in its entirety.

[0055] In the depicted embodiment, the distal electrode array comprises a plurality (seven (7)) splines supporting the electrodes. The splines can comprise, for example, a resilient and / or elastic material (e.g., a nickel -titanium alloy, such as Nitinol). The number of splines can vary as desired depending on the particular configuration, but the present electrode arrays will typically include two or more splines (e.g., greater than any one of or between any two of 3, 4, 5, 6, 7, 8, 9, or more splines).

[0056] In some configurations, each of two or more (e.g., a majority and / or all) of the splines also includes at least one positioning electrode or sensor. For example, a positioning electrode sensor can be mounted at or near a distal end of the corresponding spline, such that each positioning electrode or sensor can be used to determine a position (e.g., coordinates of) its tip electrode at each instant when the tip electrode is being used to collect an electrical mapping data point; in such configurations, both electrical and location data can be obtained for each data point that is mapped.300431716.1 - 10 -

[0057] Each location sensor is connected to a corresponding sensor wire or conductor extending through a non-conductive covering or separator, and through catheter body and control handle, to the consol (e.g., through a proximal end of the handle).

[0058] Each tip measurement / ablation electrode can have an exposed length, for example, of from 0.5 mm to about 4 mm (e.g., from about 0.5 mm to 2 mm, or equal to about 1 mm). Each tip electrode is in electrical communication with a corresponding electrode wire or conductor that is configured to communicate electrically — e.g., via the wire or conductor extending through the inner catheter — with a mapping and / or monitoring system (e.g., in the console). Each electrode lead wire or conductor can extend through the control handle, through the central lumen in the inner catheter, and into the corresponding spline, to its corresponding tip electrode (which may, for example, be defined by an exposed portion of the wire or conductor itself).

[0059] Additional details of the construction of certain aspects of a catheter can be found in United States Patent Application Publication No. US 2006 / 0276703, which is incorporated by reference in its entirety. Reference is made to FIGs. 4A-4C, which is schematic diagram showing the deployment and unfolding of one of the present distal electrode arrays.Velocity Vector Calculations

[0060] The nearly equilateral triangles defined by the electrodes in FIG. 5 A can be regarded as a triangular mesh. The right part of FIG. 5 A illustrates the calculation of the endocardial or epicardial velocity vectors for an electrical excitation wave on such a triangular mesh. A velocity vector exists at each edge. For example, the velocity V12 is calculated by< 12V12 actuation tbne2 -ac w c timelBecause the electrodes are arranged in approximately equilateral triangles, the accuracy of the calculated velocity is approximately invariant regardless of the wave front direction.Adjusted Elastic / Resilient Deformation of The Catheter

[0061] FIGs. 6A-6C depicts the deployment of an elastic / resilient distal electrode array such that the splines of the array to bring the electrodes into contact with and along a curved surface of the heart tissue.Performing Ablation Lines With The Catheter

[0062] FIG. 7 illustrates the ablation strategies ablation line (FIG. 7A-1, 7A-2) and box isolation (FIG. 7B-1, 7B-2) which can each be performed without moving the catheter, but by activating ablation electrodes (open circles) within one line or along multiple lines or curves.300431716.1 - 11 -Mapping the Entire Reentrant Circuits Over Time With The Catheter

[0063] FIG. 8 illustrates a distal electrode array of a catheter with a size that may span an entire ventricular tachycardia circuit with its VT isthmus, multiple entry and exit sites and outer loops or multiple reentries or focal activities in the atrium or the ventricle. Because of the complete coverage of the catheter and mapping with high resolution over several cycle lengths, the catheter has the capability to identify also the dynamic behavior of VT circuits over time and to localize VT- isthmus, entrance- and exit site locations of different cycles. These identified locations may be used for improving and / or optimizing ablation strategy.Mapping Of Combined Regions Of Block Based On Multiple Pacing Sites and Pacing Frequencies With The Catheter

[0064] FIGs. 9A-9C illustrate an example of a method for detecting block lines, which are wave front and frequency dependent, by pacing from five edge pacing electrodes of the depicted example of the distal electrode array of the present systems system, by combining the detected block lines from each pacing site.Mapping Of Fiber Orientation Based On Multiple Pacing Sites With The Catheter

[0065] FIG. 10 illustrates an example of a method to detect fiber orientation with high resolution by pacing from several edge pacing electrodes.Performing Bipolar Ablation Lines Between Endocardium and Epicardium With The Catheter

[0066] FIG. 11 illustrates an example of a method of bipolar ablation lines or bipolar box isolation lines between the endocardium and epicardium by using two parallel catheters at the endocardium and at the epicardium.Mapping The Entire Ventricle With The Modular Combined Catheter

[0067] FIG. 12 illustrates an example of the present multi-array catheter systems, e.g., with three (3) distal electrode arrays each having 30 electrodes (for 90 total electrodes) for mapping an entire ventricle (e.g., with high resolution). In some configurations, each of the distal electrode arrays can be carried by a different inner catheter. In other configurations, the multiple distal electrode arrays are carried by a single inner catheter such that the multiple distal electrode arrays define a combined array that is deployed as one.300431716.1 - 12 -Algorithm for New Reentry Detections

[0068] FIGs. 13-15 illustrate certain aspects of one example of an algorithm for prefiltering and detection of reentry trajectory.

[0069] In prior art methods, the trajectory of reentries was calculated based on phase singularities. However, that approach can falsely detect phase singularities in the absence of rotors. The present algorithm tracks locations of earliest / latest activation in 5-ms steps over time (schematic of the algorithm flow chart in FIG. 13), and can for example be programmed in MATLAB.

[0070] Exclusion of noise. In the first algorithm step, the bipolar peak-to-peak amplitude is calculated. Then signals with high noise-level are excluded with peak-to-peak voltage values < 0.4 milliVolt (mV) and steepest negative slope values > - 0.02 milliVolt per millisecond (mV / ms) (FIG. 13)

[0071] Highpass and Lowpass filter settings. All bipolar recordings are filtered with bandpass filtering i.e. with cutoff frequencies of 40 and 250 Hz or other filter settings were used (FIG. 14)

[0072] LAT detection. In the Matlab-modeled peak detection algorithm, the minimal time distance between neighboring peaks was set to 60 milliseconds (ms) to avoid over-detection of multiple deflections in complex electrogams, compare FIG. 14. The minimal height of the detected peaks was set to the value that equals the standard deviation of all negative slopes to filter out small, insignificant amplitude fluctuations or noise, and allows peak detections in the steepest negative slope, which are significantly larger than noise levels, compare FIG. 14.

[0073] Quantification of the percentage of double potential and fractionate signals. Additionally, as a quality measurement, the percentage of double potentials and complex fractionated signals are quantified with peak detection algorithms in Matlab without versus with the setting of a minimal time of 60 milliseconds (ms) between neighboring peaks.

[0074] Preprocessing filters . To ensure precise local activation time (LAT) detection, the algorithm uses additional advanced filters. The algorithm uses a polynomial detrend filter to remove baseline wander. The algorithm filters all bipolar recordings with bandpass filtering with cutoff frequencies of 40 and 250 Hz. The algorithm also uses a Savitzky-Golay filter to improve LAT detection from noisy and complex intracardiac electrograms. The Savitzky- Golay filter addresses challenges in LAT detection, such as noise, fractionation, and farfield interference by smoothening the electrograms while preserving the morphology, which allows a more accurate and reliable LAT calculation.300431716.1 - 13 -

[0075] Signals at Reentry. Raw electrograms were recorded at the polygon reentry center (FIG. 13D), and outer border distant to the reentry center in 30-msec steps (FIG. 13E). Circles symbolize the detected local activation time. Of note, double potentials and complex signals were more often detected at the reentry center.

[0076] Eliminating LAT over detection. The algorithm further applies a rule of a minimal distance between LAT annotations of 60ms, mimicking the refractory period to prevent LAT over-detection and improve the fidelity and reliability of LAT annotation (FIG. 13F). In the Matlab peak detection algorithm, the minimal time distance between neighboring peaks was set to 60ms. The minimal height of the detected peaks was set to the value that equals the standard deviation of the amplitudes of all negative slopes.

[0077] FIG. 13G shows a histogram of all peak detections in steepest negative slopes. FIGs. 13H and 131 show histograms of peak detections of delta peak times > 60ms and < 60ms, respectively. As a quality measurement, the algorithm quantifies the percentage of double potentials and complex fractionated signals with peak detection algorithms in Matlab without versus with the setting of a minimal time of 60ms between neighboring peaks. FIG. 13 J shows that the regional double potential percentage was highest in the PLA and LAFW and lowest in the PRA.

[0078] LAT maps. Then local activation time maps are calculated as times of the minimum in the negative slope (dV / dt) in time series of in 5 millisecond (ms) steps up to 10 seconds or longer time periods.

[0079] Isochronal maps with block lines. In the next step, interpolated isochronal maps are calculated in 5 millisecond (ms) steps. Block lines are calculated between neighbored LAT points with >50 millisecond (ms) difference.

[0080] Calculation of earliest and latest activation around block lines. Then the positions of the earliest and latest activation are calculated in each isochronal map around connected block lines. If the earliest time points occur at several locations the closest point to the block line is used using the nearest neighbor method in Matlab. The earliest and latest time points are considered to belong to one wave if the start and end points of the rotational wave are closer together than 2.5 mm. The existence of continuous paths is confirmed if the earliest activations in 5 millisecond (ms) steps were < 4 millimeters (mm) away. The reentry pathway size is measured as the number of LAT points included in each reentry pathway, and as quality criteria included reentries that were detected in at least 9 points.

[0081] Reentry detections. In the next step, the algorithm tracks the earliest and latest activation over time in 5 millisecond (ms) steps. The algorithm calculates the reentry core as300431716.1 - 14 -the center point of the earliest activation points and the angle over time between the earliest activation points and the center. An activation wavefront is considered reentry if the angle of the line between the center point and the earliest and latest activation continuously increases with a rotation angle from 0 to 360 degrees (>270 degrees). If there is a continuously increasing angle > 180 but <270 degrees, it is classified as a U-turn. If a reentry loop is detected, the reentry is displayed. These iterative steps are calculated in 10-second windows. Reentry stability is defined as the duration of observed reentrant activity over time. Additional manual annotation of 360°-rotations in local activation time maps confirmed the automatic detections. The accuracy of the reentry detection methods is assessed by comparing the phase method which focuses on the reentry core and the newly developed method based on the earliest and latest activation with manual annotations. Accuracy was defined as a measure of how often the algorithm classifies a reentry correctly. A systematic, side-by-side comparison of manual and automatic annotations of reentries and U-turns is given in FIG. 15.

[0082] Slow conduction zone detections, rotational and focal sources, and their temporal behaviors in simultaneous mapping in different atrial regions. Furthermore, the algorithm calculates activation delay and maximal activation delay in reentry trajectories and at focal sources. Slow conduction was calculated as activation time differences between neighbored electrodes in the distance of 2.5 millimeters (mm). The algorithm calculates focal activities as simultaneous earliest activities within activation time maps in 5 milliseconds (ms) time steps. The algorithm furthermore analyzes the temporal behaviors of rotational and focal activities.

[0083] FIGs. 16A, 16B, and 16C illustrate simultaneous reentry mapping over time in neighboring atrial regions with 2 or more synchronous mapping plaques. FIG. 16A includes synchronous maps showing interacting rotational activities in the PL A and LAA. FIG. 16B shows positive correlation between regional cycle length in the PLA and regional cycle length in the LAFW (R=0.5, P<0.05). FIG. 16C shows positive correlation between regional cycle length in the PLA and regional cycle length in the RAFW (R=0.8, P<0.05).* * *

[0084] The above specification and examples provide a complete description of the structure and use of illustrative configurations. Although certain configurations have been described above with a certain degree of particularity, or with reference to one or more individual configurations, those skilled in the art could make numerous alterations to the disclosed configurations without departing from the scope of this invention. As such, the various illustrative configurations of the methods and systems are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling300431716.1 - 15 -within the scope of the claims, and configurations other than the one shown may include some or all of the features of the depicted configurations. For example, elements may be omitted, modified, or combined as a unitary structure, connections may be substituted, or both.

[0085] Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and / or functions, and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one configuration or may relate to several configurations. Accordingly, no single implementation described herein should be construed as limiting and implementations of the disclosure may be suitably combined without departing from the teachings of the disclosure.

[0086] The previous description of the disclosed implementations is provided to enable a person skilled in the art to make or use the disclosed implementations. Various modifications to these implementations will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other implementations without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope possible consistent with the principles and novel features as defined by the following claims. The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.300431716.1 - 16 -

Claims

CLAIMS1. A catheter comprising: a catheter body having a proximal end, a distal end, and at least one lumen extending longitudinally through a majority of a length of the catheter body and through the distal end; a distal electrode array coupled to a distal portion of the catheter body, the distal electrode array comprising a plurality of splines each having a proximal portion and a distal end, the splines configured to in a deployed configuration spread outward from the distal end of the inner catheter body, wherein each of the splines comprises a plurality of electrodes spaced along a length of the spline.

2. The catheter of claim 1, where the distal electrode array is moveable between the deployed configuration and a retracted configuration in which the distal ends of the splines are closer to each other than when in the deployed configuration.

3. The catheter of claim 1, where the distal electrode array comprises five splines.

4. The catheter of claim 1, where the distal electrode array comprises seven splines.

5. The catheter of claim 1, where the distal electrode array comprises nine splines.

6. The catheter of claim 1, where the distal electrode array comprises twelve spines.

7. The catheter of claim 1, wherein electrodes are positioned along adjacent ones of the splines such that in the deployed configuration at least some of the electrodes each cooperate with two adjacent electrodes to define a triangle with three sides defined by the distance between respective pairs of the electrodes, wherein none of the three sides deviates in length by more than 25% of the length of the longest of the three sides.

8. The catheter of any of claims 1-7, where the distal electrode array is a first distal electrode array, and where the catheter further comprises one or more additional distal electrode arrays each coupled to a distal portion of the catheter body, each additional distal electrode array comprising a plurality of splines each having a proximal portion and a distal end, the splines of the additional distal electrode array configured to in a deployed configuration spread outward from the distal end of the inner catheter body, wherein each of300431716.1 - 17 -the splines compromises a plurality of electrodes spaced along a length of the spline.

9. A system comprising: one or more catheters of any of claims 1-8; and an outer catheter or sheath having a proximal end, a distal end, and at least one lumen extending longitudinally through the proximal end and the distal end; where the inner catheter body is configured to extend through the lumen of the outer catheter or sheath.

10. The system of claim 9, where the one or more catheters comprises a plurality of catheters of any of claims 1-7, where the lumen of the outer catheter or sheath is configured to receive the plurality of catheters.

11. A method comprising: receiving electrical signals from at least a portion of the electrodes of a catheter of any of claims 1-8 while the distal electrode array is positioned in a portion of a heart of a patient.

12. The method of claim 11, further comprising mapping, with the received electrical signals, one or more characteristics of the heart.

13. The method of claim 10, wherein the catheter covers substantially all of a ventricular tachycardia (VT) circuit, and the method further comprises: mapping a VT -isthmus of the VT circuit.

14. The method of claim 10, further comprising: detecting block lines by pacing from edge pacing electrodes of the distal electrode array.

15. The method of claim 10, further comprising: detecting fiber orientation by pacing from several edge pacing electrodes of the distal electrode array.

16. The method of any of claims 11-15, further comprising: sending electrical signals to at least a portion of the electrodes of a catheter of any of claims 1-8 while the distal electrode array is positioned in a portion of a heart of a patient.300431716.1 - 18 -17. A method comprising: sending electrical signals to at least a portion of the electrodes of a catheter of any of claims 1-8 while the distal electrode array is positioned in a portion of a heart of a patient.

18. The method of any of claims 16-17, further comprising: performing ablation along a line by sending electrical signals to a portion of the electrodes along the line.

19. The method of any of claims 16-18, further comprising: performing ablation along a box or other non-axial path by sending electrical signals to a portion of the electrodes along the box or other non-axial path.

20. The method of claim 19, as depending from claim 18, where performing ablation along a box or other closed curve is performed while the distal electrode array is in the same location as during performing ablation along the line.

21. The method of any of claims 17-20, where the catheter is a first catheter and the distal electrode array is a first distal electrode array and is positioned in contact with the endocardium of the heart, a second catheter of any of claims 1-7 is positioned such that a second distal electrode array is positioned in contact with the epicardium opposite the first electrode array, and the method further comprises: sending electrical signals to at least a portion of the electrodes of the second distal electrode array such that the ablation is performed between the endocardium and epicardium.

22. The method of any of claims 11-21, where the splines of the distal electrode area are deformed such that the electrodes contact respective portions of a curved surface of tissue of the heart.

23. The method of any of claims 11-16 and 18-22, further comprising: filtering noise from at least some of the received signals.300431716.1 - 19 -24. The method of claim 23, further comprising: calculating endocardial or epicardial propagation velocity between two electrodes based on the timing of signals received at at least one of the two electrodes and the distance between the two electrodes.

25. The method of any of claims 23-24, further comprising: calculating using the received signals earliest and latest activation points.

26. The method of claim 25, further comprising: determining using the received signals respective positions of the earliest and latest activation points.

27. The method of any of claims 23-26, further comprising: identifying from the received signals at least one of reentry or U-turn.

28. The method of claim 27, further comprising: displaying an identified reentry.

29. A multi-electrode assembly of a catheter, the multi-electrode assembly comprising: a catheter body having a proximal end and a distal end; and an arrangement of electrodes operable to couple to a distal portion of the catheter body, the arrangement of electrodes having an angular spacing between adjacent electrodes of between 130 degrees and 145 degrees.

30. The multi-electrode assembly of claim 29, where the angular spacing between adjacent electrodes is between 137 degrees and 138 degrees.

31. A system for determining cardiac tissue characteristics, the system comprising: an electrode array operable to connect to a distal portion of a catheter body, the electrode array including a plurality of electrodes arranged to include at least an approximately equilateral triangular mesh; computer-readable media storing executable instructions which, upon being executed by one or more processors, cause the system to: receive electrical signals from the plurality of electrodes; and300431716.1 - 20 -calculate an endocardial propagation velocity vector or a epicardial velocity vector for the approximately equilateral triangular mesh based at least in part on the received electrical signals.

32. A catheter system comprising: a plurality of electrodes coupled together by a plurality of splines; where at least one of the plurality of splines is configured to deform in an elastic or resilient manner to conform to a curvature of a tissue surface; and where the conforming to the curvature of the tissue surface facilitates contact between heart tissue and two or more adjacent electrodes of the plurality of electrodes.

33. The catheter system of claim 32, where the plurality of electrodes includes a multi-array electrode system formed by a plurality of electrode arrays.

34. An apparatus comprising: a catheter having a distal end; and a plurality of distal electrode arrays carried by the catheter at the distal end, the plurality of distal electrode arrays collectively defining a combined array, where the combined array is configured for deployment as a single integral unit.

35. A method comprising: calculating a plurality of first positions of an earliest activation time and a plurality of second positions of a latest activation time for a plurality of connected block lines using an isochronal map generated by a plurality of electrodes positioned at heart tissue; and confirming an existence of a continuous signal path based on whether, using a plurality of predetermined time steps, a plurality of occurrences of the earliest activation time in are < 4 millimeters apart from each other.

36. The method of claim 35, where the plurality of predetermined time steps are between 4-6 ms.

37. The method of any of claims 35 or 36, further comprising: determining whether the earliest activation time occurs at a plurality of different locations; and300431716.1 - 21 -selecting, based on the determining, a closest point to a block line of the plurality of connected block lines by using a nearest neighbor method.

38. A method compri sing : determining a plurality of local activation times (LAT)s based on an electrical signal generated by a plurality of electrodes of an electrode array of a catheter; calculating a reentry pathway size by using a number of LATs of the plurality of LATs included in a reentry pathway, the calculating of the reentry pathway uses, as quality criteria: the reentry pathway being detected at four or more activation points; and at least one of a width dimension or a length dimension of the reentry pathway being less than 10 mm.

39. A method comprising: generating, using electrical signals from a plurality of electrodes of an electrode array of a catheter, simultaneous mappings of electrode array recordings in different atrial regions; calculating temporal behaviors of one or more parameters of the simultaneous mappings, the one or more parameters including at least one of a slow conduction zone, a rotational source, or a focal source; and causing a visualization of the temporal behaviors to be presented at console of a computing device.300431716.1 - 22 -

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