Medical probe with concentric reference electrode and sensing electrode

Abstract

An electrode combination for an end effector of a catheter may include a reference electrode and a sensing electrode positioned such that the reference electrode is recessed relative to the sensing electrode such that the reference electrode is prevented from contacting tissue when the sensing electrode is in contact with tissue. The reference electrode may function to detect far-field electromagnetic noise, while the sensing electrode receives electrical signals from tissue and may also receive signals from far-field electromagnetic noise. An electrocardiogram of the electrical signal from tissue may be generated by subtracting or otherwise compensating the far-field noise received by the sensing electrode based on the far-field electromagnetic noise received by the reference electrode. Preferably, the reference electrode and the sensing electrode have the same surface area as each other.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 63 / 507,154 (Agent Docket No. BIO6819USPSP1), previously filed on June 9, 2023, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to medical devices, and in particular to electrode catheters configured to measure electrical signals of tissue, particularly cardiac tissue. Background Art

[0004] Arrhythmias, such as atrial fibrillation (AF), occur when an area of ​​cardiac tissue abnormally conducts electrical signals to adjacent tissue. This disrupts the normal cardiac cycle and causes an irregular heartbeat. Certain procedures are used to treat arrhythmias, including surgically disrupting the source of the signal causing the arrhythmia and disrupting the conduction pathways for such signals. By selectively ablating cardiac tissue through the application of energy via a catheter, it is sometimes possible to stop or alter the propagation of unwanted electrical signals from one part of the heart to another.

[0005] Many contemporary ablation methods utilize radiofrequency (RF) electrical energy to heat tissue. RF ablation may have certain rare disadvantages, such as an increased risk of thermal cell damage, which may lead to tissue charring, burns, steam bursts, phrenic nerve paralysis, pulmonary vein stenosis, and esophageal fistulas, depending on the operator's skill. Cryoablation is an alternative to RF ablation that can reduce some of the thermal risks associated with RF ablation, but tissue damage may occur due to the extremely low temperature nature of such devices. Manipulating a cryoablation device and selectively applying cryoablation is generally more challenging than RF ablation; therefore, cryoablation is not feasible in certain anatomical geometries that can be reached by electrical ablation devices.

[0006] The ablation method being developed uses irreversible electroporation (IRE) to ablate cardiac tissue using a non-thermal ablation method. To achieve IRE, short pulses of high-voltage electrical signals are delivered to the tissue, and the electrical signal generates irreversible permeabilization of the cell membrane. The use of a multi-electrode catheter to deliver IRE energy to tissue has been previously proposed in the patent literature. Examples of systems and devices configured for IRE ablation are disclosed in U.S. Patent Publications 2021 / 0169550A1, 2021 / 0169567A1, 2021 / 0169568A1, 2021 / 0161592A1, 2021 / 0196372A1, 2021 / 0177503A1, and 2021 / 0186604A1, each of which is incorporated herein by reference. U.S. Patent Publication Nos. 2021 / 0169550A1, 2021 / 0177503A1, and 2021 / 0186604A1 are attached as appendices to priority patent application No. 63 / 507,154.

[0007] Areas of cardiac tissue may be mapped by catheter to identify abnormal electrical signals. The same or different catheters may be used to perform ablation. Some catheter ablation procedures, particularly those with persistent atrial fibrillation, may be performed using electrophysiological (EP) mapping of target areas of abnormal electrical signals. Such EP mapping may include the use of sensing electrodes configured to monitor electrical signals within the cardiovascular system to accurately determine the location of abnormal conductive tissue sites that cause arrhythmias. An example of an EP mapping system is described in U.S. Patent No. 5,738,096, which is incorporated herein by reference and is attached in the appendix to priority patent application No. 63 / 507,154. Examples of EP mapping catheters are described in U.S. Patent No. 9,907,480, U.S. Patent Publication No. 2018 / 0036078, U.S. Patent Publication No. 2018 / 0056038, and U.S. Patent Publication No. 20210369339, each of which is incorporated herein by reference and is attached as an appendix to priority patent application No. 63 / 507,154.

[0008] In addition to using EP mapping, some catheter ablation procedures can also be performed using an image-guided surgery (IGS) system. An IGS system can enable a physician to visually track the position of a catheter in a patient relative to an image of the patient's anatomy in real time. Some systems can provide a combination of EP mapping and IGS functionality, including the CARTO TM3 system. An example of a catheter configured for use with an IGS system is disclosed in US Pat. No. 9,480,416, which is incorporated herein by reference and is attached as an addendum to priority patent application No. 63 / 507,154. Summary of the invention

[0009] An electrode combination for an end effector of a catheter is proposed, the electrode combination including a reference electrode and a sensing electrode, the reference electrode and the sensing electrode being positioned so that the reference electrode is recessed relative to the sensing electrode so that the reference electrode is prevented from contacting the tissue when the sensing electrode is in contact with the tissue. The reference electrode can function to detect far-field electromagnetic noise, while the sensing electrode receives electrical signals from the tissue and can also receive signals from the far-field electromagnetic noise. An electrocardiogram of the electrical signals from the tissue can be generated based on the far-field electromagnetic noise received by the reference electrode by subtracting or otherwise compensating for the far-field noise received by the sensing electrode. Preferably, the reference electrode and the sensing electrode have the same surface area as each other.

[0010] An exemplary end effector for a medical probe may include a first electrode and a second electrode. The first electrode may be disposed on a first side of the end effector. The first electrode may have a first surface exposed to the surrounding environment and configured to contact tissue. The second electrode may be disposed on the first side of the end effector. The second electrode may be at least partially circumscribed by the first electrode. The second electrode may have a second surface that is exposed to the surrounding environment and is prevented from contacting tissue by virtue of a first vertical gap between the first surface and the second surface.

[0011] Another exemplary end effector for a medical probe may include a frame, a first electrode, and a second electrode. The frame member may extend along a longitudinal axis. The first electrode and the second electrode may be disposed substantially orthogonally relative to the longitudinal axis of the frame member, such that one of the first electrode and the second electrode is recessed relative to the other of the first electrode and the second electrode to prevent such recessed electrode from contacting tissue.

[0012] An exemplary medical probe may include an elongated shaft, an end effector, and a plurality of electrode assemblies. The elongated shaft may extend along a longitudinal axis. The end effector may be coupled to a distal end of the elongated shaft. A plurality of electrode assemblies may be coupled to the end effector. Each electrode assembly in the plurality of electrode assemblies may include a corresponding inner electrode and a corresponding outer electrode disposed around at least a majority of the corresponding inner electrode and vertically offset from the corresponding inner electrode. Each corresponding inner electrode and each corresponding outer electrode may be exposed to the surrounding environment.

[0013] An exemplary method of reducing far-field signals acquired for intracardiac mapping may include the following steps performed in a variety of orders and with interleaved steps as understood by a person skilled in the relevant art. The method may include positioning a first electrode and a second electrode on a substantially planar member such that one of the first electrode and the second electrode is recessed relative to the other of the first electrode and the second electrode. The method may include sensing the far-field signals using the recessed one of the first electrode and the second electrode. The method may include sensing the cardiac signal using the other of the first electrode and the second electrode. The method may include subtracting the far-field signals from the cardiac signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Although claims are provided after the specification which particularly point out and distinctly claim the subject matter described herein, it is believed that the subject matter will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals represent the same elements. The accompanying drawings depict one or more specific implementations of the present device by way of example only and not by way of limitation.

[0015] Figure 1 is an illustration of an exemplary catheter-based electrophysiological mapping and ablation system.

[0016] Figure 2 is an illustration of an exemplary end effector of a catheter.

[0017] Figure 3A is an illustration of an exemplary end effector having an alternative electrode configuration.

[0018] Figure 3B is an illustration of a frame of an exemplary end effector.

[0019] Figure 4 Yes Figure 3A Cross-sectional illustration of an exemplary end effector indicated in FIG.

[0020] Figure 5A , Figure 5B and Figure 5C Yes Figure 4 A top view of the electrode assembly of the end effector indicated in FIG.

[0021] Figure 6 is a cross-sectional illustration of an exemplary end effector having additional structural members surrounding the frame.

[0022] Figure 7 is an illustration of an exemplary end effector having an alternative electrode support structure.

[0023] Fig. 8A , Figure 8B and Figure 8C Yes Figure 7Schematic representation of an alternative embodiment of a cross-section of the electrode combination indicated in .

[0024] Fig. 9 is an illustration of an exemplary flexible circuit layout that may be used to support an electrode assembly of an exemplary end effector.

[0025] Fig.10 is a flow chart of method steps that may be used to detect cardiac signals.

[0026] Fig.11A and Fig. 11B An exemplary magnetic sensor circuit for an end effector is shown. DETAILED DESCRIPTION

[0027] The following specific embodiments should be read in conjunction with the accompanying drawings, wherein the same elements are labeled the same in different drawings. The accompanying drawings (not necessarily drawn to scale) depict selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates the principles of the invention by way of example and not by way of limitation. This description will clearly enable those skilled in the art to prepare and use the invention, and describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including the best modes currently believed to be implemented in the invention.

[0028] As used herein, the term "about" or "approximately" for any numerical value or range indicates a suitable dimensional tolerance that allows a part or a collection of components to achieve its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of ±10% of the value of the recited value, for example, "about 90%" may refer to a range of values ​​from 81% to 99%.

[0029] In addition, as used herein, the terms "patient", "recipient", "user" and "subject" refer to any human or animal subject, and are not intended to limit the systems or methods to human use, but the use of the subject invention in human patients represents a preferred embodiment. Likewise, the term "proximal" refers to a position closer to an operator, while "distal" refers to a position farther from an operator or physician.

[0030] Alternative device and system features and alternative method steps are presented in the exemplary embodiments herein. As will be understood by those skilled in the relevant art and as expressly set forth herein, each given exemplary embodiment presented herein may be modified to include features and / or method steps presented with different exemplary embodiments herein, where such features and / or steps are compatible with a given example. Such modifications and variations are intended to be included within the scope of the claims.

[0031] Figure 1is a diagram showing an exemplary catheter-based electrophysiological mapping and ablation system 10. The system 10 includes multiple catheters that are inserted percutaneously through the patient's vascular system into a chamber or vascular structure of the heart 12 by a physician 24. Typically, a delivery sheath catheter is inserted into the left atrium or right atrium near a desired location in the heart 12. Multiple catheters may then be inserted into the delivery sheath catheter to reach the desired location. The multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters configured for both sensing and ablation. An exemplary catheter 14 configured for sensing IEGM is shown herein. The physician 24 brings the end effector 100 of the catheter 14 into contact with the heart wall for sensing a target site in the heart 12. For ablation, the physician 24 would similarly bring the distal end of the ablation catheter to the target site for ablation.

[0032] The illustrated catheter 14 is an exemplary catheter that includes one (preferably multiple) electrodes distributed over a substantially planar surface at the end effector 100 and configured to sense IEGM signals, which are configured as an electrode combination 130. Each electrode combination 130 may include a pair of electrodes that are vertically offset from each other so that one electrode is blocked from contacting the tissue and the other electrode is in contact with the tissue. The electrode in contact with the tissue can be used as a sensing electrode, and the electrode blocked from contacting the tissue can be used as a reference electrode. The electrical signal received by the sensing electrode may mainly include the IEGM signal, while the electrical signal received by the reference electrode may mainly include the far-field signal. The IEGM signal can be measured more accurately by subtracting the signal received by the reference electrode from the signal received by the sensing electrode, or reducing the far-field noise in the signal from the sensing electrode based on the signal from the reference electrode. The IEGM signal measured by multiple electrode combinations 130 can be used to determine the spatial relationship of the IEGM signal through the tissue.

[0033] The catheter 14 may further include a position sensor 29 coupled to the shaft 90 of the catheter 14 near the end effector 100 for tracking the position and orientation of the end effector 100. Optionally and preferably, the position sensor 29 is a magnetic-based position sensor that includes three magnetic coils for sensing three-dimensional (3D) position and orientation. The end effector 100 may include a magnetic field sensor such as a magnetic field sensor. Fig.11A and Fig. 11B The additional single-axis magnetic sensors 171 , 172 , 181 , variations thereof, and alternatives thereto shown in FIG. 1 are understood by those skilled in the relevant art.

[0034] The magnetic-based position sensors 29, 171, 172, 181 can operate with a positioning pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predefined workspace. The real-time position of the end effector 100 of the catheter 14 can be tracked based on the magnetic field generated using the positioning pad 25 and sensed by the magnetic-based position sensors 29, 171, 172, 181. The details of magnetic-based position sensing technology are described in U.S. Patents 5,391,199, 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, which are incorporated herein by reference.

[0035] The system 10 includes one or more electrode patches 38 positioned in contact with the skin of the patient 23 to establish a position reference for impedance-based tracking of the positioning pad 25 and electrodes including the shaft electrode 26 and / or the electrodes of the end effector electrode assembly 130. For impedance-based tracking, current is directed toward the electrodes 26, 130 and sensed at the electrode skin patch 38 so that the position of each electrode can be triangulated via the electrode patch 38. Details of impedance-based position tracking techniques are described in U.S. Patents 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182, which are incorporated herein by reference.

[0036] Recorder 11 displays electrograms 21 captured using body surface ECG electrodes 18 and intracardiac electrograms (IEGMs) captured using electrode assembly 130 of catheter 14. Recorder 11 may include pacing capabilities for pacing cardiac rhythms and / or may be electrically connected to a separate pacemaker.

[0037] The system 10 may include an ablation energy generator 50 adapted to conduct 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, radio frequency (RF) energy or pulsed field ablation (PFA) energy (including monopolar or bipolar high voltage DC pulses that may be used to achieve irreversible electroporation (IRE)), or a combination thereof.

[0038] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between catheters, electrophysiology equipment, a power source, and a workstation 55 for controlling the operation of the system 10. The electrophysiology equipment of the system 10 may include, for example, multiple catheters, positioning pads 25, surface ECG electrodes 18, electrode patches 38, ablation energy generator 50, and recorder 11. Optionally and preferably, the PIU 30 includes processing capabilities for enabling real-time calculation of the position of the catheter and for performing ECG calculations.

[0039] Workstation 55 includes memory, a processor unit with memory or storage loaded with appropriate operating software, and user interface capabilities. Workstation 55 can be configured to provide a variety of functions, optionally including: (1) three-dimensional (3D) modeling of endocardial anatomy and rendering of the model or anatomical map 20 for display on display device 27; (2) displaying on display device 27 an activation sequence (or other data) compiled from recorded electrograms 21 as representative visual markers or images superimposed on the rendered anatomical map 20; (3) displaying the real-time position and orientation of multiple catheters within the heart chamber; and (4) displaying on display device 27 sites of interest such as where ablation energy is applied. A commercial product embodying elements of system 10 is available as CARTO TM 3 systems are obtained.

[0040] Figure 2 is a more detailed illustration of the end effector 100. The shaft 90 of the catheter 14 extends along the longitudinal axis AA. The end effector 100 is coupled to the distal end of the elongated shaft 90. The end effector 100 is shown in a planar configuration such that features of the end effector 100 are orthogonal to a first orthogonal axis O1 that is orthogonal to the longitudinal axis AA, and such that features of the end effector are parallel to a plane that includes the longitudinal axis AA and a second orthogonal axis O2 that is orthogonal to the longitudinal axis AA and the first orthogonal axis O1.

[0041] The end effector 100 is configured to collapse to a diameter that is sized to fit within a sheath catheter for delivery into the heart 12 and is configured to expand to a planar configuration (or approximately planar, with a certain curvature) when pushed distally out of the distal end of the sheath catheter and suspended in a body fluid. For example, the end effector 100 can collapse by rolling or folding the outer portions 103 toward each other to helically wrap the end effector 100 along the longitudinal axis AA. When the end effector is delivered through the delivery sheath catheter, the end effector 100 can be maintained in the collapsed configuration by the delivery sheath catheter. The end effector 100 can move from a planar configuration to a collapsed configuration when it is pulled proximally into the distal end of the sheath catheter.

[0042] The end effector 100 is sufficiently flexible so that when pressed against tissue, the end effector is configured to conform to the tissue so that multiple electrodes of the end effector are in contact with the tissue simultaneously. The end effector 100 is sufficiently flexible so that when pressed against a planar surface, the end effector 100 presents a Figure 2 The planar configuration shown in .

[0043] The end effector may include a frame 150 that provides structural support for the end effector 100 and is configured to facilitate movement of the end effector 100 into a planar configuration. The end effector may include one or more diaphragms 110, 120 extending between the struts of the frame 150 (see also Figure 4 and Figure 6 ). The membranes 110, 120 may form a substrate to which the electrode assembly 130 may be coupled. The end effector has a first side 101a and a second side 101b ( Figure 4 and Figure 6 ). Each side 101a, 101b is exposed to the surrounding environment, and each electrode of each electrode combination 130 includes a surface exposed to the surrounding environment.

[0044] The end effector 100 may include openings 102, 105 to provide increased flexibility of the end effector 100. As shown, the end effector 100 includes an outer opening 102 that extends a majority of the length of the end effector when measured from the distal end of the shaft 90 to the distal end 106 of the end effector. The outer opening 102 separates the left and right portions 103 of the end effector from a central portion 107 of the end effector. As shown, the end effector 100 includes a central opening 105 that extends less than half the length of the end effector 100. The openings 102, 105 are preferably located between the columns 138 ( Figure 3A ) extend along the longitudinal axis AA.

[0045] As shown, the central portion 107 includes an array of electrode assemblies 130 coupled to a portion of the diaphragms 110, 120 extending between the struts of the frame 150. Thus, the end effector 100 need not include a frame 150 below each electrode assembly 130. At least a portion of the electrode assemblies 130 may be coupled to the diaphragms 110, 120 such that the frame does not extend below the electrode assemblies 130.

[0046] like Figure 2As shown in more detail in the illustration of , each electrode combination includes a first electrode 131 and a second electrode 132. The second electrode 132 is circumscribed by the first electrode 131. As shown, the first electrode 131 has a circular annular shape, and the second electrode 132 has a circular shape. For example, as a non-limiting example, alternative geometric shapes are envisioned: the first electrode 131 may have a square annular shape, and the second electrode 132 may have a square shape; the first electrode 131 may have a regular polygonal annular shape, and the second electrode 132 may have a regular polygonal shape; or the first electrode 131 may have an elliptical annular shape, and the second electrode 132 may have an elliptical shape. In addition, the first electrode 131 may be continuous or may be segmented. In addition, the first electrode 131 may have a serpentine annular shape and / or may include an interference cut in an annular shape to provide flexibility of the first electrode 131. Preferably, most of the periphery of the second electrode 132 is circumscribed by the first electrode 131.

[0047] The electrode combination 130 includes two electrodes 131, 132, so that one electrode of the electrode combination 130 can be used as a sensing electrode, and the other electrode in the electrode combination 130 can be used as a reference electrode. The reference electrode can function to detect far-field electromagnetic noise, while the sensing electrode receives electrical signals from the tissue and can also receive signals from the far-field electromagnetic noise. An electrocardiogram of the electrical signal from the tissue can be generated based on the far-field electromagnetic noise received by the reference electrode by subtracting or otherwise compensating for the far-field noise received by the sensing electrode.

[0048] The electrodes 131, 132 in the electrode combination may be offset vertically so that the reference electrode is prevented from contacting the tissue by virtue of the vertical gap between the exposed surfaces of the two electrodes 131, 132, while the sensing electrode is in contact with the tissue. Thus, the reference electrode is in contact with the fluid (e.g., blood) while the sensing electrode is in contact with the tissue. In some examples, the first electrode 131 (outer electrode) is configured as a sensing electrode and the second electrode 132 (inner electrode) is configured as a reference electrode. Alternatively, the end effector 100 may be modified so that the second electrode 132 is vertically elevated relative to the first electrode 131 so that the first electrode 131 is used as a reference electrode and the second electrode 132 is used as a reference electrode. In some examples, the end actuator 100 may include two types of electrode combinations: a first type electrode combination 130, in which the first electrode 131 (outer electrode) is configured as a sensing electrode and the second electrode 132 (inner electrode) is configured as a reference electrode; and a second type electrode combination 130, in which the first electrode 131 (outer electrode) is configured as a reference electrode and the second electrode 132 (inner electrode) is configured as a sensing electrode.

[0049] The electrode combinations 130 may be spaced apart from each other to form longitudinal pairs 141. Each longitudinal pair 141 may include two electrode combinations 130 both located on the same side 101a, 101b of the end effector 100. The longitudinal pair 141 thus includes two sensing electrodes, one sensing electrode from each electrode combination 130 in the longitudinal pair. The sensing electrodes may be configured to measure an electrocardiogram signal as a bipolar pair. For example, the first electrode 131 from each electrode combination 130 may be configured as a sensing electrode, and the first electrode 131 may be configured to measure an electrocardiogram signal as a bipolar pair. As described above, as an alternative, the second electrode 132 in the electrode combination 130 may be configured as a sensing electrode, and the end effector may include both the first type and the second type of electrode combination 130. Therefore, the bipolar pair functionality of the longitudinal pair 141 may be between the two outer electrodes 131, between the two inner electrodes 132, or between the outer electrode 131 and the inner electrode 132, depending on the type of electrode combination in the longitudinal pair 141.

[0050] The electrode combinations 130 can be positioned to form orthogonal pairs 142. Each orthogonal pair 142 can include a first electrode combination 130 on a first side 101a of the end effector 100 and a second electrode combination 130 on a second side 101b of the end effector 100, the second electrode combination being opposite to the first electrode combination 130. The orthogonal pairs 142 can be used to further compensate for far-field noise. When the sensing electrodes in one electrode combination are in contact with tissue, the reference electrodes in the same electrode combination are detecting far-field noise in close proximity to the tissue, while the electrodes of the opposing electrode combination are oriented away from the tissue to detect far-field noise in the blood. Thus, in addition to using the signals from the corresponding reference electrodes to compensate for far-field noise in the signals detected by the sensing electrodes, the signals detected from the electrodes in the opposing electrode combination can also be used to compensate for far-field noise.

[0051] The end effector 100 may further include a flexible polymer layer 160 as an outer packaging member. Figure 4 Discuss in more detail.

[0052] Figure 3A is an illustration of an exemplary end effector 100 having an alternative electrode configuration. The electrode combinations 130 are spaced apart in a regular grid having rows 137 of electrode combinations 130 and columns 138 of electrode combinations. The rows 137 are aligned along a second orthogonal axis. The columns 138 are aligned along the longitudinal axis AA. The alternative electrode configuration does not include the longitudinal pair 141. The alternative electrode configuration includes the orthogonal pair 142. The orthogonal pair 142 is vertically aligned along the first orthogonal axis O1 along the centerline CL and is therefore orthogonal to the end effector 100 in the planar configuration. Figure 4 Electrode pairs 130 and alignment are discussed in more detail.

[0053] Figure 3B is an illustration of a frame 150 of an exemplary end effector. The end effector may include a frame 150 that provides structural support for the end effector and is configured to facilitate movement of the end effector 100 into a planar configuration. The frame 150 may include an elastic material and may include a shape memory material, such as Nitinol. As shown, the frame 150 may be symmetrical about the longitudinal axis AA, but need not be symmetrical about the longitudinal axis AA.

[0054] Figure 4 Yes Figure 3A . A cross-sectional illustration of an exemplary end effector 100 indicated in FIG. The top surfaces 133, 134 of the first electrode 131 and the second electrode 132 are each exposed to the surrounding environment. The top surfaces 133, 134 of the two electrodes 131, 132 are separated by a vertical gap H1. The top surface of the second electrode 132 is prevented from contacting the tissue by virtue of the vertical gap H1, while the top surface of the first electrode 131 is in contact with the tissue. When the first electrode 131 is pressed into the tissue, the tissue may have some elasticity to bend downward around the edge of the first electrode 131, extending downward beyond the top surface 133 of the first electrode 131. The vertical gap H1 is large enough to prevent the tissue from extending downward to contact the top surface 134 of the second electrode 132 during typical use of the catheter 14.

[0055] Figure 5A , Figure 5B and Figure 5C Yes Figure 4 0047] Figure 2 is a top view of various possible configurations of the electrode assembly 130 of the end effector 100 indicated in FIG. Figure 5A A first electrode 131 having an uninterrupted circular annular shape and a second electrode 132 having a continuous circular annular shape are shown. Figure 5B A first electrode 131 having a discontinuous circular ring shape and a second electrode 132 having a polygonal shape are shown. Figure 5C The first electrode 131 is shown to have a serpentine continuous circular shape, which may increase the flexibility of the first electrode 131. These are examples of several possible electrode shapes.

[0056] Dimensions such as the inner diameter D3 of the first electrode 131 may affect the minimum vertical gap H1 required to prevent tissue from contacting the top surface 134 of the second electrode 132 during typical use of the catheter 14. The amount of force that the end effector 100 is configured to apply to the tissue may also affect the minimum vertical gap H1 required to prevent tissue from contacting the top surface 134 of the second electrode 132 during typical use of the catheter 14. The amount of force that the end effector 100 is configured to apply to the tissue may be primarily affected by the flexibility of the end effector 100, which may be primarily affected by the flexibility of the frame 150. The flexibility of the tissue may also affect the minimum vertical gap H1 required to prevent tissue from contacting the top surface 134 of the second electrode 132.

[0057] Common Reference Figure 4 , Figure 5A , Figure 5B and Figure 5C , the first surface area of ​​the top surface 133 of the first electrode 131 can be calculated based on its size (i.e., outer diameter D1, inner diameter D3, annular width W1 and shape). The second surface area of ​​the top surface 134 of the second electrode 132 can be calculated by its size (i.e., outer diameter D2 and shape). Preferably, the first surface area is approximately equal to the second surface area.

[0058] The first surface 133 and the second surface 134 may be laterally spaced apart from each other by a lateral gap region 136 having a gap length L1. The surface area of ​​the lateral gap region 136 may be calculated by taking the area of ​​a circle or polygon having a diameter equal to the inner diameter D3 of the first surface 133 and subtracting the area of ​​a circle or polygon having a diameter equal to the outer diameter D2 of the second surface 134. Therefore, the surface area of ​​the lateral gap region 136 may be calculated as the surface area of ​​a plane parallel to the first surface 133, parallel to the second surface 134, and laterally located between the first surface and the second surface. The surface area of ​​the lateral gap region 136 may be equal to or less than the first surface area of ​​the first surface 133 and equal to or less than the second surface area of ​​the second surface 134. The annular width W1 of the first surface 133 may be equal to or greater than the gap length L1. The outer diameter D2 of the second surface 134 may be equal to or greater than the gap length L1. Preferably, the surface area of ​​the lateral gap region 136 is about 0.83 times the second surface area and / or the first surface area to about equal to the second surface area and / or the first surface area.

[0059] In one example, the first electrode 131 has an outer diameter D1 measuring about 0.5 mm to about 0.67 mm, and the second electrode 132 has an outer diameter D2 measuring about 0.44 mm. In one example, the first surface area and the second surface area each measure about 0.15 mm 2 .

[0060] Preferably, the first surface 133 and the second surface 134 are each planar, extend along the longitudinal axis AA, and face orthogonal to the longitudinal axis AA, as shown.

[0061] refer to Figure 4 The end actuator 100 may include a frame 150, a first diaphragm 110 on a first side 101a of the end actuator 100, a second diaphragm 120 on a second side 101b of the end actuator 100, and a packaging member 160 on the first diaphragm 110 and the second diaphragm 120.

[0062] The diaphragms 110, 120 may each include a depression or recess 112 in which the reference electrode is positioned to create a vertical gap H1 between the top surfaces of the sensing electrode and the reference electrode. The recess 112 is shown as a circular recess, but may have alternative shapes depending on the alternative shapes of the electrodes 131, 132 of the electrode combination 130.

[0063] As shown, the inner electrode 132 is disposed in the recess 112, and the outer electrode 131 circumscribes the recess 112. Alternatively, the recess 112 may be configured to circumscribe the inner electrode 132, and the outer electrode 131 may be positioned in the recess such that the outer electrode 131 is prevented from contacting the tissue by virtue of the vertical gap H1 and is configured to be used as a reference electrode, while the inner electrode 132 is configured as a sensing electrode ( Figure 8B ). The recessed portion may include Fig. 8A The overhang is shown and disclosed in more detail.

[0064] The diaphragms 110, 120 may include a flexible circuit, also known in the art as a flexible printed circuit board (PCB) or a flexible PCB. The diaphragm 110 may include a layer of a flexible dielectric film (such as a polymer film) and one or more patterned conductive (e.g., metal) layers. Thus, the diaphragms 110, 120 may include multiple layers. In some examples, the polymer film may be primarily made of polyimide. In other examples, the flexible circuit may be made of any one of biocompatible polyimide, glass-reinforced epoxy laminate, copper, or graphene, either alone or in combination. To simplify the illustration, the layers of the diaphragms 110, 120 are not shown. Thus, the recess 112 may be constructed by forming an opening in one or more upper layers of the flexible circuit and / or other polymer films of a given diaphragm 110, 120. As shown, the electrodes 131, 132 may include a conductive disc that is electrically and mechanically coupled to the flexible circuit. Additionally or alternatively, the electrodes 131 , 132 may include exposed portions of the conductive layer, such that the conductive layer includes an exposed top surface 133 , 134 .

[0065] As shown, the electrode combination 130 in each orthogonal pair 142 is vertically aligned along the center line CL along the first orthogonal axis O1, wherein the center line CL passes through the center point of each electrode combination 130 of the orthogonal pair 142. The inner electrodes of the electrode combination 130 of the orthogonal pair 142 can be vertically aligned with each other, and the outer electrodes of the electrode combination 130 of the orthogonal pair 142 can be vertically aligned with each other. It should be noted that the scope of the present invention does not require that each electrode combination 130 makes their center lines CL coincide with each other. That is, the center line CL of the electrode combination 130 on the first diaphragm 110 can be offset from the corresponding center line CL of the electrode combination 130 on the second diaphragm 120. The orthogonal pair 142 includes two electrode combinations that overlap at least partially when the center lines CL are offset from each other.

[0066] The end effector 100 may also include a flexible polymer layer 160 that encapsulates the membranes 110, 120 and the frame 150. The flexible polymer layer 160 may include openings so that the electrodes 131, 132 are exposed to the surrounding environment. In some examples, the flexible polymer layer 160 may include an outer surface having a thinner portion surrounding the electrode combination 130 and a thicker portion at an approximate midpoint between the electrode combinations 130. This can improve the ability of the sensing electrodes of the electrode combination 130 to flatten the target anatomical structure. Alternatively, the flexible polymer layer 160 may include an outer surface having a thicker portion surrounding the electrode combination 130. In some examples, the frame 150 may be embedded in a flexible polymer layer 160 that is separated from the flexible circuit of the membranes 110, 120. This can increase the stiffness of the end effector 100. In some examples, the flexible polymer layer 160 may include a biocompatible silicone. In other examples, the flexible polymer layer 160 may include a biocompatible flexible polymer, a thermoelastic polymer material, and a dielectric material. Flexible polymer layer 160 may optionally be colored to facilitate laser cutting.

[0067] Figure 6 1 is a cross-sectional illustration of an exemplary end effector having an additional structural member 155 surrounding the frame 150. The structural member 155 can be disposed between the flexible circuits of the membranes 110, 120 and surrounding the frame 150 to provide a planar surface for mounting the flexible circuits. The structural member 155 can be selected from a group of materials such as polymers, metals, semi-metals, rigid, elastic or superelastic materials, and combinations thereof.

[0068] The end effector 100 may also be modified to include frames 150 of various geometries, various electrode arrangements, diaphragms 110 , 120 of various geometries, and other compatible features and variations.

[0069] Figure 71 is an illustration of an exemplary end effector 100 having an alternative electrode support structure. The end effector 100 includes a spine 190 that provides structural support for the electrode assembly 130. The spine 190 may include a flexible tubular housing and a support frame extending through the flexible tubular housing. Similar to the frame 150 ( Figure 3B ), the support frame can provide structural support to the spine so that the spine expands to a predetermined configuration when it leaves the sheath catheter. The tubular housing can have a variety of configurations. Wiring and other components can be disposed within the lumen of the tubular housing. For example, the tubular housing and components disposed therein can be configured to be similar to the spine disclosed in U.S. Patent Publication No. 2021 / 0369339, which is incorporated herein by reference and is attached in the appendix to priority patent application No. 63 / 507,154.

[0070] The electrode assembly 130 may be mounted to a membrane 110 that is attached to a spine 190, such as a polymeric tubular housing of the spine 190. The membrane 110 may include a flexible circuit configured as disclosed in greater detail elsewhere herein.

[0071] Each diaphragm 110 may include a longitudinal pair 141 of electrode combinations 130a, 130b. Each longitudinal pair 141 may be configured as a bipolar pair. Thus, the end effector 100 may include a plurality of bipolar pairs 141, each of which includes a first electrode combination 130a and a second electrode combination 130b, the first electrode combination 130a may include a first electrode and a second electrode configured as a sensing electrode and a reference electrode. The second electrode combination 130b may include a third electrode and a fourth electrode configured as a sensing electrode and a reference electrode. The reference electrode may be vertically recessed relative to the sensing electrodes in the first electrode combination 130a and the second electrode combination 130b.

[0072] like Figure 7 As shown in the inset of , the longitudinal pair 141 may include a first (outer) electrode having a first surface 133a, a second (inner) electrode having a second surface 134a, a third (outer) electrode having a third surface 133b, and a fourth (inner) electrode having a fourth surface 134b. The four electrodes are coupled to the same side of the end effector 100. The first electrode and thus the first surface 133a may be longitudinally aligned with the third electrode and thus the third surface 133b. The second electrode and thus the second surface 134a may be longitudinally aligned with the fourth electrode and thus the fourth surface 134b. Figure 2 The longitudinal pair 141 shown in FIG. 1 can also be used as described with respect to Figure 7 Configured similarly as described.

[0073] The first surface 133a and the third surface 133b are each exposed to the surrounding environment and are configured to contact tissue. The second surface 134a is circumscribed by the first surface 133a. The fourth surface 134b is circumscribed by the third surface 133b. The second surface 134a and the fourth surface 134b are each exposed to the surrounding environment.

[0074] The longitudinal pair 141 may include two electrode combinations, each of which has a sensing electrode and a reference electrode. The sensing electrodes may be aligned longitudinally. The reference electrodes may also be aligned longitudinally.

[0075] In one example, by virtue of the vertical gap H1 ( Fig. 8A ) to prevent the second surface 134a from contacting the tissue. Fig. 8A ) to prevent the fourth surface 134b from contacting the tissue. The vertical gap can be measured along the first orthogonal axis O1. The third surface 133b is preferably coplanar with the first surface 133a. The first electrode and the third electrode can be configured to measure an electrocardiogram signal as a bipolar pair.

[0076] In another example, by virtue of the vertical gap H2 ( Figure 8B ) to prevent the first surface 133a from contacting the tissue. By virtue of the vertical gap H2 ( Figure 8B ) to prevent the third surface 133b from contacting the tissue. The vertical gap can be measured along the first orthogonal axis O1. The second surface 134a is preferably coplanar with the fourth surface 134b. The second electrode and the fourth electrode can be configured to measure an electrocardiogram signal as a bipolar pair.

[0077] In another example, the longitudinal pair 141 includes two types of electrode combinations ( Fig. 8A and Figure 8B ), wherein the inner electrode is recessed in one of the electrode combinations and the outer electrode is recessed in the other electrode combination.

[0078] The electrode assemblies 130 of the longitudinal pair 141 may be spaced apart from each other by a predetermined spacing. The third surface 133b is spaced apart from the first surface 133a by a lateral gap L5 (eg, Figure 7), the lateral gap is the shortest distance measured from edge to edge from the first surface 133a to the third surface 133b. The electrode combinations 130 may be spaced apart from each other by a longitudinal spacing L2, which is measured between the center points of each electrode combination 130, i.e., from the center point of the second surface 134a to the center point of the fourth surface 134b. The longitudinal pairs 141 may be spaced apart from each other by a longitudinal spacing L3, such as measured from the center point or centroid of the surface area of ​​the electrodes of each longitudinal pair 141. For example, the longitudinal spacing L3 between the longitudinal pairs 141 may be measured from the center point between the electrode combinations 130 of the first longitudinal pair 141a to the center point between the electrode combinations 130 of the second longitudinal pair 141b, as shown in the figure.

[0079] The electrodes may be arranged in columns along the spine of the end effector 100b. The spine is separated by a column spacing L4, so that the columns of electrodes are separated by the column spacing L4.

[0080] Fig. 8A , Figure 8B and Figure 8C is a diagrammatic representation of a cross section of electrode assembly 130 . Fig. 8A is an illustration of a first type of electrode combination 130 , wherein the second electrode 132 is recessed relative to the first electrode 131 . Figure 8B is an illustration of a second type of electrode combination 130 , in which the first electrode 131 is recessed relative to the second electrode 132 . Figure 8C is an illustration of a first type of electrode combination 130 , wherein the second electrode 132 is recessed relative to the first electrode 131 and the first electrode 131 overhangs the second electrode 132 by an overhang length L6 .

[0081] like Fig. 8A As shown in , the diaphragm 110 can be shaped so that the recessed electrode is positioned in a recessed portion 112 having an overhang, so that the top periphery 114 of the recessed portion 112 overhangs the bottom periphery 115 of the recessed portion. When the geometry of the electrode assembly 130 is circular, as shown, the bottom periphery 115 of the recessed portion 112 can have a diameter D5 that is greater than the diameter D5 of the top periphery 114. In this way, the bottom surface area of ​​the recessed portion 112 can be greater than the top surface area of ​​the recessed portion 112, wherein the bottom surface area is defined as the surface area within the bottom periphery 115, and the top surface area is defined as the surface area having the top periphery 114. Similarly, Figure 4 and Figure 6 The diaphragms 110, 120 shown in FIG. 1 may include such an overhang in the recessed portion 112. Figure 8BThe electrode combination 130 shown in FIG. 1 can be modified to include an overhang above the first electrode 131. In addition, a reference electrode having an alternative geometry can be positioned within an alternatively shaped recess having an overhang. The overhang can prevent the reference electrode from contacting the tissue when the sensing electrode is in contact with the tissue.

[0082] Alternatively, if Figure 8B As shown in , the diaphragm 110 need not include an overhang above the recessed electrode. In this example, the recess 112 has a substantially uniform width D7 along the first orthogonal axis O1, and the second electrode 132 is positioned on a mesa having a substantially uniform width D6 along the first orthogonal axis O1.

[0083] Alternatively, if Figure 8C As shown in , the diaphragm 110 can be shaped so that the recessed electrode is positioned in a recessed portion 112 having an overhang so that the top perimeter 114 of the recessed portion 112 overhangs the bottom perimeter 115 of the recessed portion. The overhang can cause the first electrode 131 to overlap with the second electrode 132 by an overlap length L6. This configuration can allow the width W1 of the first electrode to be larger without increasing the diameter D1 of the first electrode 131, thereby increasing the contact surface area of ​​the first electrode 131. Similar to Fig. 8A Compared with the electrode combination design shown in FIG. , the effective surface area 132 can remain substantially the same, wherein the second electrode 132 is Fig. 8A and Figure 8C Both have the same surface area as the top surface 133 .

[0084] Fig. 9 1 is an illustration of an exemplary diaphragm 110 having a flexible circuit layout that may be used to support an electrode assembly 130 of an exemplary end effector 100. As discussed in greater detail herein, the flexible circuit may include multiple layers and may include one or more patterned conductive layers 143. Fig. 9 The pattern of the conductive layer of the flexible circuit is shown. A longitudinal gap L2 between the electrode combinations 130 of the first longitudinal pair 142a is shown. A longitudinal gap L3 between the first longitudinal pair 141a and the second longitudinal pair 141b is shown.

[0085] Fig.10200 is a flow chart of method steps that may be used to detect a cardiac signal. At box 202, a first electrode and a second electrode may be located on a generally planar member such that one of the first electrode and the second electrode is recessed relative to the other of the first electrode and the second electrode. The first electrode and the second electrode may be configured as an electrode combination 130. At box 204, a far-field signal may be sensed using the recessed electrode of the first electrode and the second electrode. At box 206, a cardiac signal may be sensed using the other of the first electrode and the second electrode. At box 208, the far-field signal may be subtracted from the cardiac signal.

[0086] Fig.11A and Fig. 11B An exemplary magnetic sensor circuit of the end effector 100 is shown. The end effector 100 may include a plurality of inductive coils or loops 171, 172, 181 having respective axes orthogonal to the end effector 100 in a planar configuration. As shown, the end effector 100 includes a first inductive loop 181, a second inductive loop 171, and a third inductive loop 173. The first inductive loop 181 is disposed near the distal end of the end effector 100. A majority of the second inductive loop 171 and a majority of the third inductive loop 172 are disposed in a proximal direction relative to the first inductive loop 181. The second inductive loop 171 and the third inductive loop 172 may be elongated along a longitudinal axis and positioned as mirror images of each other about the longitudinal axis. The first inductive loop 181 may be rectangular. The loops 171, 172, 181 may be coplanar with each other. The flexible polymer layer 160 may have layers removed inside the coils 171, 172, 181 to make the end effector 100 more flexible while maintaining the geometric integrity and sensing capabilities of the coils 171, 172, 181. The loops 171, 172, 181 may be used as magnetic position sensors, such as with respect to Figure 1 The magnetic sensor circuit may include a first loop circuit 180, the first loop circuit including a first loop 181 and a proximal trace conductor 182, the proximal trace conductor being configured to deliver an electrical signal sensed by the first loop 181 to the PIU 30 ( Figure 1 ). The magnetic sensor circuit may include a second loop circuit 170 including a second loop 171, a third loop 172, and a proximal trace conductor 173, the proximal trace conductor being configured to deliver an electrical signal sensed by the second loop 171 and the third loop 172 to the PIU 30. The magnetic sensor circuit may be included in a patterned conductor layer of a flexible circuit of the first diaphragm 110 and / or the second diaphragm 120.

[0087] Exemplary embodiments of the subject matter contained herein have been shown and described, and further improvements of the methods and systems described herein may be achieved by appropriate modifications without departing from the scope of the claims. For example, as understood by those skilled in the relevant art, the catheter disclosed in the references incorporated herein by reference and / or attached in the appendix to priority patent application No. 63 / 507,154 may be modified to include one or more electrode combinations 130 or arrangements thereof as disclosed herein. In addition, where the above methods and steps represent specific events occurring in a specific order, it is intended that certain specific steps do not necessarily have to be performed in the order described, but may be performed in any order, as long as the steps enable the embodiment to achieve its intended purpose. Therefore, if there are variations of the present invention and the variations fall within the essential scope of the disclosure of the present invention or equivalents that can be found in the claims, this patent is intended to cover these variations as well. Many such modifications will be apparent to those skilled in the art. For example, the examples, embodiments, geometries, materials, dimensions, ratios, steps, etc. described above are all exemplary. Therefore, the claims should not be limited to the specific details of the structure and operation shown in this written description and the drawings.

[0088] The following clauses set forth non-limiting embodiments of the present disclosure:

[0089] Item 1. An end effector for a medical probe, the end effector comprising: a first electrode, the first electrode being located on a first side of the end effector, the first electrode comprising a first surface, the first surface being exposed to the surrounding environment and being configured to contact tissue; and a second electrode, the second electrode being located on the first side of the end effector, the second electrode being at least partially circumscribed by the first electrode, the second electrode comprising a second surface, the second surface being exposed to the surrounding environment and being prevented from contacting tissue by virtue of a first vertical gap between the first surface and the second surface.

[0090] Item 2. An end actuator for a medical probe, the end actuator comprising: a frame member extending along a longitudinal axis; and a first electrode and a second electrode, the first electrode and the second electrode being arranged substantially orthogonally relative to the longitudinal axis of the frame member, such that one of the first electrode and the second electrode is recessed relative to the other of the first electrode and the second electrode to prevent such recessed electrode from contacting tissue.

[0091] Clause 3. The end effector of Clause 2, wherein the first electrode and the second electrode are disposed on a substrate, spaced apart from and not in contact with the frame member.

[0092] Clause 4. The end effector of clause 3, wherein the frame member is encapsulated in a polymer to maintain a gap from the frame member to the first electrode and the second electrode.

[0093] Clause 5. The end effector of any one of clauses 1 to 4, wherein the second electrode is completely circumscribed by the first electrode.

[0094] Clause 6. The end effector of any one of clauses 1 to 4, wherein the first electrode comprises a plurality of arcuate segments disposed around a periphery of the second electrode such that the plurality of arcuate segments are spaced apart from one another.

[0095] Clause 7. The end effector of any one of Clauses 1 to 6, the first electrode comprising one of an annular shape or a segmented annulus, and the second electrode comprising one of a circular shape or a polygon.

[0096] Clause 8. The end effector of Clause 7, the first electrode comprising a first outer diameter measuring from about 0.5 mm to about 0.67 mm.

[0097] Clause 9. The end effector of clause 7 or 8, the second electrode comprising a second outer diameter measuring approximately 0.44 mm.

[0098] Clause 10. The end effector of any one of Clauses 1 to 9, the first electrode comprising a first surface area that is substantially equal to a second surface area of ​​the second electrode.

[0099] Clause 11. The end effector of any one of clauses 1 to 10, wherein the first electrode comprises a thickness of about 0.15 mm. 2 The first surface area.

[0100] Clause 12. The end effector of any one of clauses 1 to 10, wherein the second electrode comprises a thickness of about 0.15 mm. 2 The second surface area.

[0101] Item 13. An end actuator according to any one of items 1 to 12, wherein the first surface is laterally separated from the second surface by a first lateral gap region, the first lateral gap region has a surface area approximately equal to the first surface area and / or the second surface area, and the first lateral gap region is a planar surface area parallel to the first surface, parallel to the second surface and located between the first surface and the second surface.

[0102] Clause 14. An end actuator according to any one of clauses 1 to 13, wherein the first surface is laterally separated from the second surface by a first lateral gap area, the first lateral gap area is approximately equal to or smaller than the first surface area and approximately equal to or smaller than the second surface area, the first lateral gap area is a planar surface area parallel to the first surface, parallel to the second surface and located between the first surface and the second surface, the first surface includes an annular width equal to or greater than the annular width of the first lateral gap area, and the second surface includes a diameter equal to or greater than the annular width of the first lateral gap area.

[0103] Clause 15. The end effector of Clause 14, wherein the annular width of the first lateral clearance region is approximately equal to 0.83 times the second surface area and / or 0.83 times the first surface area.

[0104] Clause 16. The end effector of any one of clauses 1 to 15, the first electrode being configured to measure electrocardiographic signals from tissue and the second electrode being configured to sense far-field signals.

[0105] Clause 17. The end effector of any one of Clauses 1 to 16, the first surface and the second surface comprising planar surfaces.

[0106] Clause 18. The end effector of any one of Clauses 1 to 17, the first surface and the second surface extending along a longitudinal axis and facing orthogonal to the longitudinal axis.

[0107] Clause 19. The end effector according to any one of clauses 1 to 18, further comprising: a first side, the first side comprising a recessed portion, such that the first electrode is coupled to the first side and circumscribes the recessed portion, and the second electrode is disposed in the recessed portion.

[0108] Clause 20. The end effector of clause 19, wherein the second electrode is coupled to the first side at a bottom of the recess, and the recess comprises a larger diameter at the bottom compared to a diameter at a top of the recess.

[0109] Clause 21. The end effector according to any one of clauses 1 to 20, further comprising: a third electrode coupled to a first side of the end effector and comprising a third surface exposed to the surrounding environment and configured to contact tissue, the third surface being coplanar with the first surface and separated from the first surface by a second lateral gap; and a fourth electrode coupled to the first side of the end effector and circumscribed by the third electrode, the fourth electrode comprising a fourth surface, the fourth surface being exposed to the surrounding environment and being prevented from contacting tissue by virtue of a second vertical gap between the third surface and the fourth surface, such that the second vertical gap is measured substantially orthogonal to the third surface and orthogonal to the fourth surface.

[0110] Clause 22. The end effector of clause 21, wherein the first electrode and the third electrode are configured as a bipolar pair to measure an electrocardiogram signal.

[0111] Clause 23. The end effector of clause 21 or 22, wherein the second surface is laterally spaced apart from the fourth surface by approximately 0.85 mm when measured from a center point of the second surface to a center point of the fourth surface.

[0112] Clause 24. The end effector of any one of Clauses 21 to 23, the first electrode being longitudinally aligned with the third electrode, and the second electrode being longitudinally aligned with the fourth electrode.

[0113] Clause 25. The end actuator according to any one of clauses 21 to 24 further includes: a plurality of bipolar pairs, each of the bipolar pairs including a first electrode combination and a second electrode combination, the first electrode combination including the first electrode and the second electrode, the second electrode combination including a third electrode, the third electrode being connected to a fourth electrode, and the fourth electrode being vertically recessed relative to the third electrode.

[0114] Item 26. An end actuator according to Item 25, wherein the plurality of bipolar pairs include a second bipolar pair that is spaced apart from the first bipolar pair by approximately 2.4 mm as measured from a center point or centroid of a surface area of ​​the first bipolar pair and a center point or centroid of a surface area of ​​the second bipolar pair.

[0115] Clause 27. The end effector of clause 25 or 26, the plurality of bipolar pairs comprising between six and twenty-four bipolar pairs.

[0116] Clause 28. The end actuator according to any one of clauses 1 to 27 further includes: a fifth electrode, which is coupled to a second side of the end actuator facing in an opposite direction to the first side, the fifth electrode including a fifth surface exposed to the surrounding environment, and the fifth surface is vertically aligned with the first surface of the first electrode; a sixth electrode, which is coupled to the second side and is externally connected to the fifth electrode, the sixth electrode including a sixth surface, the sixth surface is exposed to the surrounding environment and is spaced apart from the fifth surface by a third vertical gap, so that the third vertical gap is measured orthogonally to the fifth surface and orthogonally to the sixth surface.

[0117] Clause 29. The end effector of clause 28, wherein the fifth electrode is configured as a reference electrode to the first electrode.

[0118] Clause 30. The end effector of any one of clauses 1 to 29, the end effector being substantially planar along a longitudinal axis.

[0119] Clause 31. The end actuator according to any one of clauses 1 to 30, further comprising: a frame comprising one or more struts extending along a longitudinal axis; and a first diaphragm extending between the one or more struts on a first side of the end actuator and exposed to the surrounding environment, the first electrode and the second electrode being attached to the first diaphragm such that the second electrode is disposed within a recessed portion of the first diaphragm.

[0120] Clause 32. The end actuator according to clause 31 further includes: a plurality of first electrode combinations, the plurality of first electrode combinations being attached to the first diaphragm and forming rows and columns of an electrode array, such that each electrode combination of the plurality of first electrode combinations includes a corresponding first electrode, the corresponding first electrode including a corresponding first surface, the corresponding first surface being exposed to the surrounding environment and configured to contact tissue, and a corresponding second electrode including a corresponding second surface, the corresponding second surface being exposed to the surrounding environment and being prevented from contacting tissue by virtue of a corresponding first vertical gap between the corresponding first surface and the corresponding second surface, such that the corresponding first vertical gap is measured orthogonally to the corresponding first surface and orthogonally to the corresponding second surface.

[0121] Clause 33. The end actuator according to clause 32 further includes: a second diaphragm, the second diaphragm extending between the one or more pillars so that at least a portion of the frame is between the first diaphragm and the second diaphragm, the second diaphragm being exposed to the surrounding environment; and a plurality of second electrode combinations, the plurality of second electrode combinations being attached to the second diaphragm so that each of the plurality of second electrode combinations is substantially opposite to and spaced apart from a corresponding electrode combination of the plurality of first electrode combinations, each of the plurality of second electrode combinations comprising a corresponding first electrode, the corresponding first electrode comprising a corresponding first surface, the corresponding first surface being exposed to the surrounding environment and configured to contact tissue, and a corresponding second electrode comprising a corresponding second surface, the corresponding second surface being exposed to the surrounding environment and being prevented from contacting tissue by virtue of a corresponding first vertical gap between the corresponding first surface and the corresponding second surface, such that the corresponding first vertical gap is measured orthogonally to the corresponding first surface and orthogonally to the corresponding second surface.

[0122] Clause 34. An end actuator according to any one of clauses 1 to 33, wherein the end actuator is configured to expand to a planar configuration, and the end actuator further comprises: a plurality of induction loops coupled to the end actuator such that each of the plurality of induction loops comprises a corresponding axis of the end actuator that is orthogonal to the planar configuration.

[0123] Item 35. An end actuator according to Item 34, wherein the multiple induction loops include a first induction loop, a second induction loop, and a third induction loop, the first induction loop is arranged near the distal end of the end actuator, and wherein a majority of the second induction loop and a majority of the third induction loop are arranged in a proximal direction relative to the first induction loop.

[0124] Clause 36. The end effector of clause 35, wherein the second inductive loop is positioned as a mirror image of the third inductive loop.

[0125] Item 37. A medical probe, comprising: an elongated shaft extending along a longitudinal axis; an end actuator coupled to a distal end of the elongated shaft; and a plurality of electrode combinations coupled to the end actuator, each of the plurality of electrode combinations comprising a corresponding inner electrode and a corresponding outer electrode, the corresponding outer electrode being disposed around at least a majority of the corresponding inner electrode and vertically offset from the corresponding inner electrode, each corresponding inner electrode and each corresponding outer electrode being exposed to a surrounding environment.

[0126] Clause 38. The medical probe of Clause 37, wherein each respective inner electrode is prevented from contacting tissue by virtue of the respective outer electrode being vertically offset from the respective inner electrode.

[0127] Clause 39. The medical probe of clause 37 or 38, each respective first electrode being configured to measure an electrocardiogram signal from tissue, and each respective second electrode being configured to sense a far-field signal.

[0128] Item 40. A medical probe according to any one of items 37 to 39, wherein the end actuator includes a bipolar pair, the bipolar pair including two electrode combinations from the multiple electrode combinations, so that the bipolar pair is configured to detect a voltage difference between the corresponding external electrodes of the two electrode combinations of the bipolar pair.

[0129] Item 41. A method for reducing far-field signals acquired for intracardiac mapping, the method comprising: positioning a first electrode and a second electrode on a substantially planar member such that one of the first electrode and the second electrode is recessed relative to the other of the first electrode and the second electrode; sensing far-field signals using the recessed electrode of the first electrode and the second electrode; sensing cardiac signals using the other of the first electrode and the second electrode; and subtracting the far-field signals from the cardiac signals.

[0130] Clause 42. The method of Clause 41, wherein the first electrode comprises a first surface area and the second electrode comprises a second surface area substantially equal to the first surface area.

[0131] Clause 43. The method of Clause 41, wherein the first electrode at least partially circumscribes the second electrode.

[0132] Exemplary embodiments of the subject matter contained herein have been shown and described, and further improvements of the methods and systems described herein may be achieved by appropriate modifications without departing from the scope of the claims. In addition, where the above methods and steps represent specific events that occur in a specific order, it is intended that certain specific steps do not necessarily have to be performed in the order described, but can be performed in any order, as long as the steps enable the implementation to achieve its intended purpose. Therefore, if there are variations of the present invention and the variations belong to the substantive scope of the disclosure of the present invention or equivalents that can be found in the claims, this patent is intended to cover these variations as well. Many such modifications will be obvious to those skilled in the art. For example, the examples, embodiments, geometries, materials, dimensions, ratios, steps, etc. described above are all exemplary. Therefore, the claims should not be limited to the specific details of the structure and operation shown in this written description and the drawings.

Claims

1. An end effector for a medical probe, the end effector include: a frame member extending along a longitudinal axis; as well as A first electrode and a second electrode are disposed substantially orthogonally relative to the longitudinal axis of the frame member such that one of the first electrode and the second electrode is recessed relative to the other of the first electrode and the second electrode to prevent such recessed electrode from contacting tissue.

2. The end effector according to claim 1, in, The first electrode and the second electrode are disposed on a substrate, spaced apart from the frame member and not in contact with the frame member.

3. The end effector according to claim 2, in, The frame member is encapsulated in a polymer to maintain a gap from the frame member to the first electrode and the second electrode.

4. The end effector according to claim 1, in, The second electrode is completely circumscribed by the first electrode.

5. The end effector according to claim 1, in, The first electrode includes a plurality of arc segments disposed around a periphery of the second electrode such that the plurality of arc segments are spaced apart from each other.

6. The end effector of claim 1, the first electrode comprising a first surface area that is substantially equal to a second surface area of ​​the second electrode.

7. The end effector of claim 1, the first electrode being configured to measure electrocardiogram signals from tissue, and the second electrode being configured to sense far-field signals.

8. The end effector according to claim 1, further comprising: include: A first side includes a recessed portion, such that the first electrode is coupled to the first side and circumscribes the recessed portion, and the second electrode is disposed in the recessed portion.

9. The end effector according to claim 1, further comprising: include: A plurality of bipolar pairs, each of the bipolar pairs comprising a first electrode combination and a second electrode combination, wherein the first electrode combination comprises the first electrode and the second electrode, and the second electrode combination comprises a third electrode, wherein the third electrode is circumscribed to a fourth electrode, and the fourth electrode is vertically recessed relative to the third electrode.

10. The end effector of claim 1, wherein the end effector is substantially planar along a longitudinal axis.

11. The end effector according to claim 1, further comprising: include: a frame comprising one or more struts extending along a longitudinal axis; as well as A first diaphragm extends between the one or more struts on a first side of the end effector and is exposed to an ambient environment, the first electrode and the second electrode attached to the first diaphragm such that the second electrode is disposed within a recess of the first diaphragm.

12. The end effector according to claim 1, in, The end effector is configured to expand to a planar configuration, the end effector further comprising: A plurality of inductive loops are coupled to the end effector such that each of the plurality of inductive loops includes a respective axis that is orthogonal to the end effector in the planar configuration.

13. An end effector for a medical probe, the end effector include: a first electrode located on a first side of the end effector, the first electrode comprising a first surface exposed to an ambient environment and configured to contact tissue; as well as A second electrode is disposed on the first side of the end effector, the second electrode being at least partially circumscribed by the first electrode, the second electrode including a second surface that is exposed to the surrounding environment and is prevented from contacting tissue by virtue of a first vertical gap between the first surface and the second surface.

14. The end effector of claim 13, the first surface and the second surface comprising planar surfaces.

15. The end effector of claim 13, the first surface and the second surface extending along a longitudinal axis and facing orthogonal to the longitudinal axis.

16. The end effector according to claim 13, further comprising: include: A frame member extends along a longitudinal axis, wherein the first electrode and the second electrode are disposed on a substrate, spaced apart from and not in contact with the frame member.

17. The end effector according to claim 13, further comprising: include: A first side includes a recessed portion, such that the first electrode is coupled to the first side and circumscribes the recessed portion, and the second electrode is disposed in the recessed portion.

18. The end effector according to claim 13, further comprising: include: a third electrode coupled to the first side of the end effector and comprising a third surface exposed to the ambient environment and configured to contact tissue, the third surface being coplanar with the first surface and spaced apart from the first surface by a second lateral gap; as well as a fourth electrode coupled to the first side of the end effector and circumscribed by the third electrode, the fourth electrode comprising a fourth surface exposed to the ambient environment and prevented from contacting tissue by virtue of a second vertical gap between the third surface and the fourth surface, such that the second vertical gap is measured substantially orthogonal to the third surface and orthogonal to the fourth surface.

19. The end effector of claim 18, wherein the first electrode and the third electrode are configured as a bipolar pair to measure an electrocardiogram signal.

20. The end effector according to claim 13, further comprising: include: A plurality of bipolar pairs, each of the bipolar pairs comprising a first electrode combination and a second electrode combination, wherein the first electrode combination comprises the first electrode and the second electrode, and the second electrode combination comprises a third electrode, wherein the third electrode is circumscribed to a fourth electrode, and the fourth electrode is vertically recessed relative to the third electrode.

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