Coated end effector electrode for sensing and ablation

Abstract

A medical probe may include electrodes for ablating and sensing proximity to tissue and / or monitoring electrical signals within the cardiovascular system to identify aberrant conductive tissue sites that cause arrhythmia. The electrode may be oriented on an end effector assembly, such as a basket assembly, such that one side of the electrode is positioned to contact tissue and the opposite side is inhibited from contacting tissue. To achieve both efficient delivery of energy and high sensitivity for ECG sensing, an impedance reducing coating may be positioned on the tissue contacting side and an impedance increasing coating may be applied on the opposite side. The impedance increasing coating of the IRE electrode may be sufficiently thin to allow energy to be delivered across the coating during ablation. The RF electrode may have sufficient mass to carry electrical energy for thermal ablation.

Description

Technical Field

[0001] The present invention relates generally to medical devices, and more particularly to medical probes, such as catheters, configured to sense tissue proximity and deliver ablation therapy. Background Technology

[0002] Arrhythmias, such as atrial fibrillation (AF), occur when a region of heart tissue abnormally transmits electrical signals to adjacent tissues. This disrupts the normal cardiac cycle and leads to irregular heartbeats. Certain procedures are used to treat arrhythmias, including surgically disrupting the signal source causing the arrhythmia and interfering with the conduction pathways used for such signals. By selectively ablating heart tissue through the application of energy via a catheter, it can sometimes be possible to stop or alter the propagation of unwanted electrical signals from one part of the heart to another.

[0003] Many contemporaneous catheter-based ablation methods utilize radio frequency (RF) electrical energy to heat tissue. Cryoablation is an alternative catheter-based method to RF ablation, which uses low temperature rather than heat to disable electrical signals passing through the tissue. Irreversible electroporation (IRE) is a more recent catheter-based electroablation method that uses non-thermal ablation to ablate cardiac tissue. To achieve IRE, short pulses of high-voltage electrical signals are delivered to the tissue; the electrical signals generate irreversible cell membrane permeability. The use of multi-electrode catheters to deliver IRE energy to tissue has previously been proposed in patent literature. Examples of systems and apparatuses configured for IRE ablation are disclosed in U.S. Patent Publications Nos. 2021 / 0169550A1, 2021 / 0169567A1, 2021 / 0169568A1, 2021 / 0161592A1, 2021 / 0196372A1, 2021 / 0177503A1, and 2021 / 0186604A1, each of which is incorporated herein by reference.

[0004] Regions of cardiac tissue can be mapped using catheters to identify abnormal electrical signals. The same or different catheters can be used for ablation. Some catheter ablation procedures, particularly those for persistent atrial fibrillation, can be performed using electrophysiological (EP) mapping to target regions of abnormal electrical signals. Such EP mapping may include the use of sensing electrodes configured to monitor electrical signals within the cardiovascular system to precisely pinpoint the location of arrhythmogenic, abnormally conductive tissue sites. An example of an EP mapping system is described in U.S. Patent No. 5,738,096, which is incorporated herein by reference and appended to this appendix. Examples of EP mapping catheters are described in U.S. Patent Nos. 9,907,480, 2018 / 0036078, and 2018 / 0056038, each of which is incorporated herein by reference and appended to this appendix.

[0005] In addition to EP mapping, some catheter ablation procedures can be performed using image-guided surgery (IGS) systems. IGS systems allow physicians to visually track the catheter's position within the patient's body in real time, relative to images of the patient's anatomy. Some systems offer a combination of EP mapping and IGS functionality, including Biosense Webster, Inc. of Irvine, Calif's CARTO 3. ® Examples of catheters configured for use with an IGS system are disclosed in U.S. Patent No. 9,480,416, which is incorporated herein by reference. Summary of the Invention

[0006] A medical probe may include electrodes configured to perform electroablation using intra-ablation resection (IRE) and / or thermal ablation, while also being configured for sensing functions such as sensing proximity to tissue and / or monitoring electrical signals within the cardiovascular system to identify abnormally conductive tissue sites leading to arrhythmias. When configured for thermal ablation, the electrodes have sufficient mass to carry electrical energy and provide thermal conduction and stability for the ablation process. The electrodes may be oriented on an end effector assembly, such as a basket assembly, such that one side of the electrode is positioned to contact tissue and the opposite side is inhibited from contacting tissue. To achieve both efficient energy delivery and high sensitivity for ECG sensing, an impedance-reducing coating may be positioned on the tissue-contacting side, and an impedance-increasing coating may be applied on the opposite side. When configured for IRE, the impedance-increasing coating is configured to provide sufficient resistance to provide specificity for tissue proximity indication measurements, while being thin enough to allow electrical energy to be delivered through the impedance-increasing coating during IRE.

[0007] An example medical probe includes a shaft, a plurality of ridges, and a plurality of electrodes. The shaft extends along a longitudinal axis. The plurality of ridges extend from a distal end of the shaft and are configured to unfold away from the longitudinal axis to form a resilient basket. Each of the plurality of electrodes includes: a respective conductive body external to a respective ridge of the plurality of ridges; an impedance-reducing coating located on an outer surface of the respective conductive body such that the outer surface faces away from the longitudinal axis; and an impedance-increasing coating located on an inner surface of the respective conductive body such that the inner surface faces the longitudinal axis.

[0008] An example method includes: providing a medical probe having: an axis extending along a longitudinal axis; a plurality of ridges extending from a distal end of the axis and configured to unfold away from the longitudinal axis to form an elastic basket; and a plurality of electrodes, each of the plurality of electrodes having a respective conductive body external to a respective ridge of the plurality of ridges; applying an impedance-reducing coating to an outer surface of the respective conductive body of each of the plurality of electrodes such that the outer surface faces away from the longitudinal axis; and applying an impedance-increasing coating to an inner surface of the respective conductive body such that the inner surface faces the longitudinal axis.

[0009] An example system includes a medical probe and a control console. The medical probe includes: a shaft; one or more ridges extending from a distal end of the shaft; and a plurality of electrodes, each having a corresponding conductive body external to a corresponding ridge of the one or more ridges. Each of the plurality of electrodes has an impedance-reducing coating on a first surface of the corresponding conductive body and an impedance-increasing coating on a second surface of the corresponding conductive body. The control console includes at least one processor and a non-transitory computer-readable medium in communication with the at least one processor. The non-transitory computer-readable medium includes instructions thereon that, when executed by the processor, cause the control console to: sense contact between at least a portion of the plurality of electrodes and tissue, in part based on impedance measurements between one or more electrode pairs of the plurality of electrodes; and provide electrical energy to at least a portion of the plurality of electrodes to ablate the tissue. Attached Figure Description

[0010] Although a claim that specifically points out and clearly claims protection for the subject matter described herein is provided after the specification, it is believed that the subject matter will be better understood through the description of certain examples below in conjunction with the accompanying drawings, in which similar reference numerals denote the same elements. The drawings depict one or more specific embodiments of the apparatus of the invention by way of example only and not by way of limitation.

[0011] Figure 1The illustrations are examples of catheter-based electrophysiological mapping and ablation systems according to various aspects of the present invention.

[0012] Figure 2 This is an illustration of the distal portion of a catheter according to various aspects of the present invention.

[0013] Figure 3A and Figure 3B This is a diagram showing the opposite sides of the electrodes according to various aspects of the present invention.

[0014] Figure 4 This is a flowchart of a method 100 for configuring coated electrodes for electrocardiogram sensing. Detailed Implementation

[0015] The following detailed description should be read in conjunction with the accompanying drawings, in which the same elements are labeled the same in different figures. The drawings (not necessarily drawn to scale) depict selected embodiments and are not intended to limit the scope of the invention. The principles of the invention are illustrated by way of example rather than limitation. This description will clearly enable those skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including those currently believed to be the best mode for carrying out the invention.

[0016] As used herein, the term “about” or “approximately” for any numerical value or range indicates appropriate dimensional tolerances that allow a collection of parts or components to achieve the intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of ±10% of the enumerated values, for example, “about 90%” may refer to a range of 81% to 99% of the values.

[0017] 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 system or method to human use, but the use of the subject matter invention in human patients represents a preferred embodiment. Similarly, the term “proximal” refers to a position closer to the operator, while “distal” refers to a position further away from the operator or physician.

[0018] Alternative device and system features, as well as alternative method steps, are presented in the example embodiments herein. As will be understood by those skilled in the art and as expressly stated herein, each given example embodiment presented herein can be modified to include features and / or method steps presented with different example embodiments herein, wherein such features and / or steps are compatible with the given example. Such modifications and variations are intended to be included within the scope of the claims.

[0019] Electrodes positioned on end effectors of catheters for energy delivery and ECG sensing are typically chosen to have low impedance to achieve both efficient energy delivery and high sensitivity for ECG sensing. Electrodes with high energy delivery, particularly those for delivering RF electrical signals for thermal ablation, require sufficient mass to carry both electrical and thermal energy. Cylindrical electrodes can be used for this purpose because they have a greater mass than alternative electrode shapes, such as surface-mount electrodes and / or flexible circuit electrodes. Cylindrical electrodes have straight, parallel sides and a circular, elliptical, or rounded rectangular cross-section with a central opening. The cylindrical electrode may be threaded onto a ridge of the end effector at the distal end of the medical probe. The cylindrical electrode is an example of an electrode shape comprising a conductive body of the ridge of the external end effector; however, as those skilled in the art will understand, the examples herein can be modified to include electrodes with alternative shapes.

[0020] Local tissue proximity indicator (TPI) detection is based on the sensed impedance between electrodes. The detected impedance increases significantly when the electrical signal passes through or near the tissue wall compared to when the electrical signal passes completely through the blood pool. When using cylindrical electrodes, the electrical signal is distributed across the entire front and back of the electrode. However, the back of the electrode will always be in the blood pool. Due to the low-resistance contact between the back of the electrode and the blood, the overall change in detected impedance when the front of the electrode touches the tissue may be small. The assessment of tissue contact can be determined based on the sensed impedance between the electrodes using various methods, such as those disclosed in U.S. Patent No. 11,523,750, which is incorporated herein by reference and appended to this appendix.

[0021] The embodiments presented herein include an impedance-reducing coating on the front side of the electrode and an impedance-increasing coating on the back side of the electrode. Therefore, when in contact with blood, the impedance across the blood increases on the back side of the electrode compared to contact with tissue, and the impedance change is more significant on the front side of the contact. Thus, compared to electrodes with similar configurations without a back coating and a front coating, the overall change in impedance between the electrodes is larger when in contact with tissue. Therefore, in at least some applications, electrode coatings can make TPI impedance measurements more sensitive. Some embodiments present catheters configured for IRE. In such embodiments, the impedance-increasing coating is configured to provide sufficient resistance to provide specificity for tissue proximity indication measurements, while being thin enough to allow electrical energy delivery through the impedance-increasing coating during IRE. An example of a suitable impedance-reducing coating is Amplicoat, available from Heraeus Medevio. ® Amplicoat ® It is a biocompatible conductive polymer technology. Amplicoat ®The coating can be applied using electrodeposition, which utilizes a current flowing across the surface to grow the coated layer. As those skilled in the art will understand, alternative conductive coatings, such as TiOx and IrOx, can be used. An example of a suitable impedance-enhancing coating is silicon nitride (Si3N4). Silicon nitride coatings can be applied using aerosol deposition. In the example illustrated herein, the cell (the shape of the electrode) facilitates separation between the two coatings in an easy and efficient manner.

[0022] Figure 1 This is an illustration of an example catheter-based electrophysiological mapping and ablation system 10. System 10 includes multiple catheters inserted by a physician 24 through the skin into a chamber or vascular structure of the heart 12 within the patient's vascular system. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location within the heart 12. Multiple catheters can then be inserted into the delivery sheath catheter to reach that desired location. These multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters dedicated to both sensing and ablation. An example catheter 14 configured for IRE and / or RF ablation is illustrated herein. In some embodiments, catheter 14 is also configured for IEGM sensing. When configured for IRE, accurate tissue proximity indication is important to ensure proper catheter contact with tissue for ablation. When configured for RF ablation, it is important that the electrodes have sufficient thermal mass to perform thermal ablation. Physician 24 contacts the distal end 28 of catheter 14 with the heart wall to sense a target site in the heart 12. For ablation, physician 24 similarly guides the distal end of the ablation catheter to the target site for ablation.

[0023] The illustrated catheter 14 is an exemplary catheter that includes one (and preferably multiple) electrode 40 optionally distributed on a plurality of ridges 22 at its distal end 28. As shown, the ridges 22 are shaped to form an elastic basket, referred herein as basket assembly 100. The electrode 40 is configured to deliver RF ablation energy to tissue and to function as a TPI sensor. Some or preferably all of the electrodes 40 include an impedance-reducing coating 42 on the outer surface (front) and an impedance-increasing coating 44 on the inner surface (back) to increase the sensitivity of TPI measurements.

[0024] The catheter 14 may additionally include a position sensor 29 embedded in or near the distal end 28 for tracking the position and orientation of the distal end 28. Optionally and preferably, the position sensor 29 is a magnetic-based position sensor that includes three magnetic coils for sensing three-dimensional (3D) positioning and orientation. The magnetic-based position sensor 29 may operate in conjunction with a positioning pad 25, which includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predefined workspace. The real-time position of the distal end 28 of the catheter 14 can be tracked based on the magnetic field generated by the positioning pad 25 and sensed by the magnetic-based position sensor 29. Details of the magnetic position sensing technology are described in U.S. Patents Nos. 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.

[0025] System 10 includes one or more electrode patches 38 positioned for skin contact on a patient 23 to establish a position reference for positioning pad 25. The distal end 28 of the catheter may include impedance-based tracking of electrode 40 or additional electrodes (not illustrated). For impedance-based tracking, current is directed toward the electrode at the distal end of the catheter and sensed at the electrode skin patch 38, allowing triangulation of the position of each electrode via the electrode patch 38. Details of the impedance-based position tracking technique 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.

[0026] Recorder 11 displays an electrogram 21 captured using surface ECG electrodes 18 and an intracardiac electrogram (IEGM) captured using electrodes 40 using catheter 14. Recorder 11 may include pacing capability for pacing rhythms and / or may be electrically connected to a separate pacemaker.

[0027] System 10 may include an ablation energy generator 50 adapted to conduct ablation energy to electrode 40. 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 can be used to achieve irreversible electroporation (IRE), or combinations thereof.

[0028] The patient interface unit (PIU) 30 is an interface configured to establish electrical communication between catheters, electrophysiological equipment, a power supply, and a workstation 55 for operating the system 10. The electrophysiological equipment of the system 10 may include, for example, multiple catheters (including catheter 14), a positioning pad 25, surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 includes processing capabilities for real-time calculation of catheter position, sensing tissue proximity of electrodes 40, controlling the ablation energy to electrodes 40, and performing ECG calculations.

[0029] Workstation 55 includes a memory, a processor unit with a memory or storage device loaded with appropriate operating software, and user interaction capabilities. Workstation 55 can be configured to provide a variety of functions, optionally including: (1) three-dimensional (3D) modeling of the endocardial anatomy and rendering the model or anatomical mapping 20 for display on display device 27; (2) displaying on display device 27 a sequence of activations (or other data) compiled from recorded electrophysiological maps 21 as representative visual markers or images superimposed on the rendered anatomical mapping 20; (3) displaying the real-time position and orientation of multiple catheters within the cardiac chambers; and (4) displaying on display device 27 sites of interest, such as where ablation energy has been applied. An element embodying system 10 may be traded under the name CARTO. ™ The system was purchased from Biosense Webster, Inc., California.

[0030] PIU 30 and / or workstation 55 include a console housed within or distributed between PIU 30 and workstation 55. The console is configured to control ablation output and measure tissue proximity via electrode 40. The console includes at least one processor and a non-transitory computer-readable medium in communication with the at least one processor. The non-transitory computer-readable medium includes instructions thereon that, when executed by the processor, cause the console to: sense contact between at least a portion of the plurality of electrodes and tissue, in part based on impedance measurements between one or more electrode pairs of the plurality of electrodes, and to supply electrical energy to at least a portion of the plurality of electrodes to ablate the tissue.

[0031] Impedance measurement between electrode pairs can be based at least in part on the impedance of the impedance-reducing coating 42 of electrode 40 and the impedance-increasing coating 44. The console can be configured to sense contact between at least a portion of electrode 40 and tissue, based in part on impedance measurements between one or more electrode pairs and assuming that the impedance-increasing coating of each electrode in the electrode pair is in contact with blood. Optionally, the console can also be configured to generate an electrocardiogram based at least in part on electrical signals received from at least a portion of electrode 40.

[0032] Figure 2 This is an illustration of the distal end 28 of catheter 14, showing the distal portion of shaft 84 and an end effector having a ridge 72 and an electrode 40. The shaft extends along a longitudinal axis 86. Ridge 72 extends from the distal end 90 of shaft 84 and is configured to unfold away from the longitudinal axis 84 to form an elastic basket. Each electrode has a corresponding conductive body, an impedance-reducing coating 42, and an impedance-increasing coating 44. The conductive body is externally attached to the corresponding ridge 72. The conductive body is oriented such that its outer surface faces away from the longitudinal axis, and its inner surface faces the longitudinal axis. Therefore, when the end effector is deployed in a patient, the inner surface is inhibited from contacting tissue and thus comes into contact with blood (or other bodily fluids). The outer surface is positioned such that it can contact tissue. Electrode 40 includes an impedance-reducing coating 42 on the outer surface of the corresponding conductive body and an impedance-increasing coating 44 on the inner surface of the corresponding conductive body.

[0033] Each electrode 40 is configured to sense tissue contact and provide ablation energy. In some embodiments, the impedance-reducing coating comprises a conductive polymer. In some embodiments, the impedance-increasing coating comprises ceramic. In some embodiments, the impedance-increasing coating has a thermal conductivity of approximately 7 W / mK to approximately 30 W / mK; or approximately 7 W / mK to approximately 28 W / mK; or approximately 30 W / mK. In some embodiments, the impedance-increasing coating comprises silicon nitride. In some embodiments, the electrode 40 is configured for electrocardiogram sensing.

[0034] As those skilled in the art will understand, the end effector may have various alternative configurations, including alternative basket assembly configurations and ray or shovel configurations. In such configurations, when the end effector is deployed in a patient, the electrode 40 may be positioned and otherwise configured to have an impedance-reducing coating 42 on a surface capable of contacting tissue and an impedance-increasing coating 44 on a surface inhibited from contacting tissue, as will be understood by those skilled in the art.

[0035] Figure 3A and Figure 3BThis is an illustration of opposite sides of electrode 40. Electrode 40 has a conductive body 46 with a cylindrical shape and an opening 48 passing through it. The conductive body 46 is sized to provide sufficient thermal mass so that electrode 40 can deliver RF energy to tissue without causing thermal damage to the end effector. The opening 48 is sized to receive a ridge 72 so that electrode 40 can be threaded onto the ridge 72 during manufacturing. As shown, the conductive body 46 has a rounded rectangular or stadium-shaped cross-section with linear sides corresponding to the outer and inner surfaces and rounded sides extending between the outer and inner surfaces. The shape of conductive body 46 facilitates the application of impedance-reducing coating 42 and impedance-increasing coating 44 on opposite sides of conductive body 46 without overlap. Conductive body 46 may have alternative cross-sectional shapes (e.g., circular, rectangular, elliptical, triangular, etc.) as understood by those skilled in the art. As shown, coatings 42, 44 do not significantly affect the overall shape of electrode 40.

[0036] As shown in the figure, opening 48 is also a rounded rectangle or stadium shape. As shown, opening 48 is centered from left to right and offset outwards from the center. Opening 48 can be offset to provide desired heat conduction to tissues and heat dissipation to blood.

[0037] Figure 3A The front or outer surface of electrode 40 is shown, along with an impedance-reducing coating 42 located on the front or outer surface of conductive body 46. As shown, the impedance-reducing coating 42 is confined to a flat portion of the outer surface. The outer surface is shaped such that during treatment, when in contact with tissue, the entire flat surface contacts the tissue, while the curved edges of the outer surface partially contact the tissue. The advantage of this configuration is that when the outer surface contacts the tissue, the entire impedance-reducing coating 42 contacts the tissue, without any portion contacting the blood. The low-resistance path through the blood reduces TPI sensitivity. By positioning the impedance-reducing coating 42 such that the entire coating 42 contacts the tissue, the coating does not provide a low-resistance path through the blood when electrode 40 contacts the tissue. Alternatively, the impedance-reducing coating 42 may be applied over a portion of the curved surface of the outer surface.

[0038] Figure 3BThe back or inner surface of electrode 40 is shown, and an impedance-increasing coating 44 is shown on the back or inner surface of conductive body 46. As shown, the impedance-increasing coating 44 is confined to a flat portion of the inner surface. The inner surface may be shaped to facilitate movement of the end effector (e.g., deployment and collapse of the basket assembly). The impedance-increasing coating 44 may be confined to areas not intended, anticipated, and / or configured to contact tissue when the end effector is deployed in the patient's body. Alternatively, the impedance-increasing coating 44 may extend around the surface of conductive body 46 and terminate adjacent to an impedance-decreasing coating 42.

[0039] Figure 4 This is a flowchart of a method 100 for configuring a coated electrode for electrocardiogram sensing. The resulting electrode may be configured similarly to electrode 40, an alternative form thereof, or a variation thereof, as understood by those skilled in the art based on the disclosure herein.

[0040] At frame 102, an impedance-reducing coating may be applied to the outer surface of the corresponding conductive body of each of the plurality of electrodes of the basket-type conduit end effector, such that the outer surface is opposite to the longitudinal axis. In some embodiments, the impedance-reducing coating is applied by electrodeposition. In some embodiments, the impedance-reducing coating comprises a conductive polymer. The impedance-reducing coating may include materials and applications, alternative forms or variations thereof, as disclosed elsewhere herein, as understood by those skilled in the art based on the disclosure herein. The outer surface may be shaped, positioned and otherwise configured as disclosed elsewhere herein, alternative forms or variations thereof, as understood by those skilled in the art based on the disclosure herein.

[0041] At frame 104, an impedance-enhancing coating may be applied to the inner surface of the corresponding conductive body, such that the inner surface faces the longitudinal axis. In some embodiments, the impedance-enhancing coating comprises ceramic. In some embodiments, the impedance-enhancing coating has a thermal conductivity of approximately 30 W / mK. In some embodiments, the impedance-enhancing coating comprises silicon nitride. The impedance-enhancing coating may include materials and applications, alternative forms or variations thereof, as disclosed elsewhere herein, as understood by those skilled in the art based on the disclosure herein. The inner surface may be shaped, positioned and otherwise configured as disclosed elsewhere herein, alternative forms or variations thereof, as understood by those skilled in the art based on the disclosure herein.

[0042] At frame 106, multiple electrodes may be positioned such that a reducing impedance coating is configured as a contact structure and at least a majority of an increasing impedance coating is suppressed as a contact structure. As understood by those skilled in the art based on the disclosure herein, the coating may be positioned on the conductive body of an electrode, an alternative form thereof, or a variation thereof, as disclosed elsewhere herein.

[0043] At box 108, each of the plurality of electrodes may be configured to sense tissue contact and provide ablation energy. The electrodes may be configured to sense tissue contact using TPI measurement techniques, alternative forms thereof, or variations thereof disclosed elsewhere herein, as understood by those skilled in the art based on the disclosure herein. A coating may be positioned on the electrodes to increase the sensitivity of the TPI measurement. The electrodes may be shaped, sized, and otherwise configured to provide ablation energy, alternative forms thereof, or variations thereof, as understood by those skilled in the art based on the disclosure herein.

[0044] At box 110, each of the plurality of electrodes may be configured for electrocardiogram sensing. The electrodes may be configured to sense electrical signals passing through cardiac tissue for electrocardiogram measurements using techniques, alternative forms thereof, or variations thereof disclosed elsewhere herein, as understood by those skilled in the art based on the disclosure herein.

[0045] The following provisions set forth non-restrictive embodiments of this disclosure: Clause 1. A medical probe comprising: an axis (84) extending along a longitudinal axis (86); a plurality of ridges (72) extending from a distal end (90) of the axis (84) and configured to unfold away from the longitudinal axis to form an elastic basket; and a plurality of electrodes (40), each of the plurality of electrodes comprising: a respective conductive body external to a respective ridge of the plurality of ridges; an impedance-reducing coating (42) located on an outer surface of the respective conductive body such that the outer surface is opposite to the longitudinal axis; and an impedance-increasing coating (44) located on an inner surface of the respective conductive body such that the inner surface is facing the longitudinal axis.

[0046] Clause 2. The medical probe according to Clause 1, wherein each of the plurality of electrodes is configured to sense tissue contact and provide ablation energy.

[0047] Clause 3. The medical probe according to Clause 1 or 2, wherein the impedance-reducing coating comprises a conductive polymer.

[0048] Clause 4. The medical probe according to any one of Clauses 1 to 3, wherein the impedance-enhancing coating comprises ceramic.

[0049] Clause 5. The medical probe according to any one of Clauses 1 to 4, wherein the impedance-enhancing coating has a thermal conductivity of approximately 30 W / mK.

[0050] Clause 6. The medical probe according to any one of Clauses 1 to 5, wherein the impedance-enhancing coating comprises Si3N4.

[0051] Clause 7. The medical probe according to any one of Clauses 1 to 6, wherein each of the plurality of electrodes is configured for electrocardiogram sensing.

[0052] Clause 8. The medical probe according to any one of Clauses 1 to 7, wherein the impedance-reducing coating is thinner than the impedance-increasing coating.

[0053] Clause 9. The medical probe according to any one of Clauses 1 to 8, wherein the plurality of electrodes are configured to provide irreversible electroporation to tissue.

[0054] Clause 10. The medical probe according to any one of Clauses 1 to 9, wherein the plurality of electrodes are configured to deliver radiofrequency ablation to tissue.

[0055] Clause 11. The medical probe according to any one of Clauses 1 to 10, wherein the impedance-reducing coating has a lower impedance than the impedance-increasing coating.

[0056] Clause 12. The medical probe according to Clause 11, wherein, when irreversible electroporation is applied, the impedance difference between the impedance-reducing coating and the impedance-increasing coating is less than the impedance difference between the impedance-reducing coating and the impedance-increasing coating during electrocardiogram sensing.

[0057] Clause 13. A method comprising: providing a medical probe, the medical probe including: an axis extending along a longitudinal axis; a plurality of ridges extending from a distal end of the axis and configured to unfold away from the longitudinal axis to form a resilient basket; and a plurality of electrodes, each of the plurality of electrodes including a respective conductive body external to a respective ridge of the plurality of ridges; applying an impedance-reducing coating to an outer surface of a respective conductive body of each of the plurality of electrodes such that the outer surface faces away from the longitudinal axis; and applying an impedance-increasing coating to an inner surface of the respective conductive body such that the inner surface faces the longitudinal axis.

[0058] Clause 14. The method according to Clause 13, wherein applying the impedance-reducing coating comprises electrodepositing the impedance-reducing coating.

[0059] Clause 15. The method of claim 13 or 14, wherein applying the impedance-enhancing coating comprises aerosol deposition of the impedance-enhancing coating.

[0060] Clause 16. The method according to any one of Clauses 13 to 15, wherein the impedance-reducing coating comprises a conductive polymer.

[0061] Clause 17. The method according to any one of Clauses 13 to 16, wherein the impedance-enhancing coating comprises ceramic.

[0062] Clause 18. The method according to any one of Clauses 13 to 17, wherein the impedance-enhancing coating has a thermal conductivity of approximately 30 W / mK.

[0063] Clause 19. The method according to any one of Clauses 13 to 18, wherein the impedance-enhancing coating comprises Si3N4.

[0064] Clause 20. The method according to any one of Clauses 13 to 19, wherein applying the impedance-reducing coating comprises configuring the impedance-reducing coating to contact tissue, and wherein applying the impedance-increasing coating comprises positioning the impedance-increasing coating such that at least a majority of the impedance-increasing coating is inhibited from contacting tissue.

[0065] Clause 21. The method according to any one of Clauses 13 to 20, the method further comprising: configuring each of the plurality of electrodes to sense tissue contact and provide ablation energy.

[0066] Clause 22. The method according to any one of Clauses 13 to 21, the method further comprising: configuring each of the plurality of electrodes to sense an electrocardiogram.

[0067] Clause 22. The method according to any one of Clauses 13 to 21, wherein the impedance-reducing coating is thinner than the impedance-increasing coating.

[0068] Clause 23. The method according to any one of Clauses 13 to 22, the method comprising configuring the plurality of electrodes to provide irreversible electroporation to tissue.

[0069] Clause 24. The method according to any one of Clauses 13 to 23, the method comprising configuring the plurality of electrodes to deliver radiofrequency ablation to tissue.

[0070] Clause 25. The method according to any one of Clauses 13 to 24, wherein the impedance-reducing coating has a lower impedance than the impedance-increasing coating.

[0071] Clause 26. The method according to any one of Clauses 13 to 25, the method comprising configuring the plurality of electrodes such that when irreversible electroporation is applied, the impedance difference between the impedance-reducing coating and the impedance-increasing coating is less than the impedance difference between the impedance-reducing coating and the impedance-increasing coating during electrocardiogram sensing.

[0072] Clause 27. A system comprising: a medical probe including: an axis; one or more ridges extending from a distal end of the axis; and a plurality of electrodes, each of the plurality of electrodes including a respective conductive body external to a respective ridge of the one or more ridges, each of the plurality of electrodes including an impedance-reducing coating on a first surface of the respective conductive body and an impedance-increasing coating on a second surface of the respective conductive body; and a console including at least one processor and a non-transitory computer-readable medium communicating with the at least one processor and including instructions thereon, the instructions, when executed by the processor, causing the console to: sense contact between at least a portion of the plurality of electrodes and tissue, in part based on impedance measurements between one or more electrode pairs of the plurality of electrodes, and to provide electrical energy to at least a portion of the plurality of electrodes to ablate the tissue.

[0073] Clause 28. The system according to Clause 27, wherein the impedance measurement between the one or more electrode pairs is based at least in part on the impedance of the coating decreasing and the impedance of the coating increasing for each of the one or more electrode pairs.

[0074] Clause 29. The system according to Clause 27 or 28, wherein the non-transitory computer-readable medium includes instructions thereon that, when executed by the processor, cause the console to: sense contact between at least a portion of the plurality of electrodes and tissue, based in part on the impedance measurement between the one or more electrode pairs and assuming that the impedance of each of the one or more electrode pairs increases in contact with blood.

[0075] Clause 30. The system according to any one of Clauses 27 to 29, wherein the electrical energy includes radio frequency ablation energy.

[0076] Clause 31. The system according to any one of Clauses 27 to 30, wherein the impedance-reducing coating comprises a conductive polymer.

[0077] Clause 32. The system according to any one of Clauses 27 to 31, wherein the impedance-enhancing coating comprises ceramic.

[0078] Clause 33. The system according to any one of Clauses 27 to 32, wherein the impedance-enhancing coating has a thermal conductivity of approximately 30 W / mK.

[0079] Clause 34. The system according to any one of Clauses 27 to 33, wherein the impedance-reducing coating is thinner than the impedance-increasing coating.

[0080] Clause 35. The system according to any one of Clauses 27 to 34, wherein the console is configured to provide electrical pulses to the plurality of electrodes to provide irreversible electroporation to the tissue.

[0081] Clause 36. The system according to any one of Clauses 27 to 35, wherein the console is configured to provide electrical waveforms to the plurality of electrodes to provide radiofrequency ablation to tissue.

[0082] Clause 37. The system according to any one of Clauses 27 to 36, wherein the impedance-reducing coating has a lower impedance than the impedance-increasing coating.

[0083] Clause 38. The system according to any one of Clauses 27 to 37, wherein, when irreversible electroporation is applied, the impedance difference between the impedance-reducing coating and the impedance-increasing coating is less than the impedance difference between the impedance-reducing coating and the impedance-increasing coating during electrocardiogram sensing.

[0084] Exemplary embodiments of the subject matter contained herein have been shown and described, and further improvements to the methods and systems described herein can be achieved through appropriate modifications without departing from the scope of the claims. For example, alternative materials may be used for the electrode conductive body, impedance-reducing coatings, and impedance-increasing coatings. Medical probes may have alternative configurations for alternative non-invasive in vivo tissue ablation treatments. The ridges of the end effector may have alternative configurations, such as star-shaped, ray-shaped, shovel-shaped, etc. Furthermore, where the foregoing methods and steps represent specific events occurring in a particular order, it is intended herein that specific steps need not necessarily be performed in the described order, but may be performed in any order, as long as the step enables the embodiment to achieve its intended purpose. Therefore, if variations of the invention exist and these variations fall within the substantial scope of the disclosure or equivalents of the invention 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 illustrative. Therefore, the claims should not be limited to the specific details of the structures and operations shown in this written description and the accompanying drawings.

Claims

1. A medical probe, the medical probe comprising: A shaft, which extends along a longitudinal axis; Multiple ridges extend from the distal end of the shaft and are configured to unfold away from the longitudinal axis to form an elastic basket; and Multiple electrodes, each of the multiple electrodes comprising: A corresponding conductive body, wherein the corresponding conductive body is externally connected to a corresponding ridge among the plurality of ridges; An impedance-reducing coating is applied to the outer surface of the corresponding conductive body, such that the outer surface is opposite to the longitudinal axis; and An impedance-enhancing coating is applied to the inner surface of the corresponding conductive body, such that the inner surface faces the longitudinal axis.

2. The medical probe according to claim 1, wherein, Each of the plurality of electrodes is configured to sense tissue contact and provide ablation energy.

3. The medical probe according to claim 1, wherein, The impedance-reducing coating comprises a conductive polymer.

4. The medical probe according to claim 1, wherein, The impedance-enhancing coating comprises ceramic.

5. The medical probe according to claim 1, wherein, The impedance-enhancing coating has a thermal conductivity of approximately 7 W / mK to approximately 30 W / mK.

6. The medical probe according to claim 1, wherein, The impedance-enhancing coating comprises Si3N4.

7. The medical probe according to claim 1, wherein, Each of the plurality of electrodes is configured for electrocardiogram sensing.

8. A method, the method comprising: A medical probe is provided, the medical probe comprising: a shaft extending along a longitudinal axis; a plurality of ridges extending from a distal end of the shaft and configured to unfold away from the longitudinal axis to form an elastic basket; and a plurality of electrodes, each of the plurality of electrodes comprising a respective conductive body externally connected to a respective ridge of the plurality of ridges; An impedance-reducing coating is applied to the outer surface of the corresponding conductive body of each of the plurality of electrodes, such that the outer surface is opposite to the longitudinal axis; and An impedance-enhancing coating is applied to the inner surface of the corresponding conductive body, such that the inner surface faces the longitudinal axis.

9. The method according to claim 8, wherein, Applying the impedance-reducing coating includes electrodepositing the impedance-reducing coating.

10. The method according to claim 8, wherein, Applying the impedance-enhancing coating includes aerosol deposition of the impedance-enhancing coating.

11. The method according to any one of claims 8, wherein, The impedance-reducing coating comprises a conductive polymer.

12. The method according to any one of claims 8, wherein, The impedance-enhancing coating comprises ceramic.

13. A system comprising: A medical probe comprising: a shaft; one or more ridges extending from a distal end of the shaft; and a plurality of electrodes, each comprising a corresponding conductive body external to a corresponding ridge of the one or more ridges, each electrode comprising an impedance-reducing coating on a first surface of the corresponding conductive body and an impedance-increasing coating on a second surface of the corresponding conductive body; and A console, comprising at least one processor and a non-transitory computer-readable medium communicating with the at least one processor and having instructions thereon, the instructions causing the console, when executed by the processor, to: The contact between at least a portion of the plurality of electrodes and the tissue is sensed, in part, based on impedance measurements between one or more electrode pairs of the plurality of electrodes. Electrical energy is supplied to at least a portion of the plurality of electrodes to ablate tissue.

14. The system according to claim 13, wherein, The impedance measurement between the one or more electrode pairs is based at least in part on the impedance of each electrode in the one or more electrode pairs decreasing the impedance of the coating and increasing the impedance of the coating.

15. The system according to claim 13, wherein, The non-transitory computer-readable medium includes instructions thereon that, when executed by the processor, cause the console to: The contact between at least a portion of the plurality of electrodes and the tissue is sensed, in part based on the impedance measurement between the one or more electrode pairs and assuming that the impedance of each electrode in the one or more electrode pairs increases in contact with the blood.

16. The system according to claim 13, wherein, The electrical energy includes radio frequency ablation energy.

17. The system according to claim 13, wherein, The impedance-reducing coating comprises a conductive polymer.

18. The system according to claim 13, wherein, The impedance-enhancing coating comprises ceramic.

19. The system according to claim 13, wherein, The impedance-enhancing coating has a thermal conductivity of approximately 30 W / mK.

20. The system according to claim 13, wherein, The impedance-enhancing coating comprises Si3N4.

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