EP-4740884-A1 - COATED END EFFECTOR ELECTRODES FOR SENSING AND ABLATION

EP4740884A1EP 4740884 A1EP4740884 A1EP 4740884A1EP-4740884-A1

Abstract

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

Inventors

GOVARI, ASSAF
Beeckler, Christopher Thomas
KEYES, JOSEPH

Assignees

Biosense Webster (Israel) Ltd.

Dates

Publication Date: 20260513
Application Date: 20251111

Claims (15)

A medical probe comprising: a shaft (84) extending along a longitudinal axis (86); a plurality of spines (72) extending from a distal end (90) of the shaft (84) and configured to expand away from the longitudinal axis to form a resilient basket; and a plurality of electrodes (40), each electrode of the plurality of electrodes comprising: a respective electrically conductive body circumscribing a respective spine of the plurality of spines, an impedance reducing coating (42) on an outer surface of the respective electrically conductive body such that the outer surface faces away from the longitudinal axis, and an impedance increasing coating (44) on an inner surface of the respective electrically conductive body such that the inner surface faces toward the longitudinal axis.
The medical probe of claim 1, wherein each electrode of the plurality of electrodes is configured to sense tissue contact and provide ablation energy.
The medical probe of claim 1, wherein the impedance reducing coating comprises a conductive polymer and/or the impedance increasing coating comprises a ceramic.
The medical probe of any preceding claim, wherein the impedance increasing coating comprises a thermal conductivity of approximately 7 W/mK to approximately 30 W/mK.
The medical probe of any preceding claim, wherein each electrode of the plurality of electrodes is configured for electrocardiogram sensing.
A method, comprising: providing a medical probe comprising a shaft extending along a longitudinal axis, a plurality of spines extending from a distal end of the shaft and configured to expand away from the longitudinal axis to form a resilient basket, and a plurality of electrodes each comprising a respective electrically conductive body circumscribing a respective spine of the plurality of spines; applying an impedance reducing coating to an outer surface of a respectively conductive body of each electrode of the plurality of electrodes such that the outer surface faces away from the longitudinal axis; and applying an impedance increasing coating on an inner surface of the respective electrically conductive body such that the inner surface faces toward the longitudinal axis.
The method of claim 6, wherein applying the impedance reducing coating comprises electrodepositing the impedance reducing coating and/or aerosol depositing the impedance increasing coating.
The method of any one of either of claims 6 or 7, wherein the impedance reducing coating comprises a conductive polymer and/or the impedance increasing coating comprises a ceramic.
A system comprising: a medical probe comprising a shaft, one or more spines extending from a distal end of the shaft, and a plurality of electrodes each comprising a respective electrically conductive body circumscribing a respective spine of the one or more spines, each of the plurality of electrodes comprising an impedance reducing coating on a first surface of the respective electrically conductive body and an impedance increasing coating on a second surface of the respective electrically conductive body; and a console comprising at least one processor and non-transitory computer-readable medium in communication with the at least one processor and comprising instructions thereon, that when executed by the processor, cause the console to: sense, based in part on an impedance measurement between one or more electrode pairs of the plurality of electrodes, contact of at least a portion of the plurality of electrodes with tissue, and provide electrical energy to at least a portion of the plurality of electrodes to ablate tissue.
The system of claim 9, wherein the impedance measurement between the one or more electrode pairs is based at least in part on an impedance of the impedance reducing coating and an impedance of the impedance increasing coating of each electrode of the one or more electrode pairs.
The system of either of claims 9 and 10, wherein the non-transitory computer-readable medium comprises instructions thereon, that when executed by the processor, cause the console to: sense, based in part on the impedance measurement between the one or more electrode pairs and assuming that the impedance increasing coating of each electrode of the one or more electrode pairs is in contact with blood, contact of at least a portion of the plurality of electrodes with tissue.
The system of any of claims 9 to 11, wherein the electrical energy comprises radiofrequency ablation energy.
The system of any of claims 9 to 12, wherein the impedance reducing coating comprises a conductive polymer and/or the impedance increasing coating comprises a ceramic.
The system of any of claims 9 to 13, wherein the impedance increasing coating comprises a thermal conductivity of approximately 30 W/mK.
The medical probe of any of claims 1 to 4 or the system of any of claims 9 to 14, wherein the impedance increasing coating comprises Si 3 N 4 .

Description

FIELD The present invention relates generally to medical devices, and in particular to medical probes such as catheters configured to sense tissue proximity and delivery ablation therapy. BACKGROUND Cardiac arrhythmias, such as atrial fibrillation (AF), occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue. This disrupts the normal cardiac cycle and causes asynchronous rhythm. Certain procedures exist for treating arrhythmia, including surgically disrupting the origin of the signals causing the arrhythmia and disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. Many contemporaneous catheter-based ablation approaches utilize radiofrequency (RF) electrical energy to heat tissue. Cryoablation is an alternative catheter-based approach to RF ablation that disable electrical signals through tissue with low temperate rather than heat. Irreversible electroporation (IRE) is a recent catheter-based electrical ablation approach to ablate cardiac tissue using nonthermal ablation. To achieve IRE, short pulses of high voltage electrical signals are delivered to tissues; the electrical signals generate an unrecoverable permeabilization of cell membranes. Delivery of IRE energy to tissues using multi-electrode catheters was previously proposed in the patent literature. Examples of systems and devices configured for IRE ablation are disclosed in U.S. Patent Pub. No. 2021/0169550A1, 2021/0169567A1, 2021/0169568A1, 2021/0161592A1, 2021/0196372A1, 2021/0177503A1, and 2021/0186604A1, each of which are incorporated herein by reference. Regions of cardiac tissue can be mapped by a catheter to identify the abnormal electrical signals. The same or different catheter can be used to perform ablation. Regions of cardiac tissue can be mapped by a catheter to identify the abnormal electrical signals. The same or different catheter may be used to perform ablation. Some catheter ablation procedures, especially those with persistent atrial fibrillation, may be performed using electrophysiology (EP) mapping to target areas of aberrant electrical signals. Such EP mapping may include the use of sensing electrodes configured to monitor electrical signals within the cardiovascular system to pinpoint the location of aberrant conductive tissue sites that are responsible for the arrhythmia. Examples of an EP mapping system are described in U.S. Patent No. 5,738,096, incorporated herein by reference and attached in the Appendix hereto. Examples of EP mapping catheters are described in U.S. Patent No. 9,907,480, U.S. Patent Pub. No. 2018/0036078, and U.S. Patent Pub. No. 2018/0056038, each of which are incorporated herein by reference and attached in the Appendix hereto. In addition to using EP mapping, some catheter ablation procedures may be performed using an image guided surgery (IGS) system. The IGS system may enable the physician to visually track the location of the catheter within the patient, in relation to images of anatomical structures within the patient, in real time. Some systems may provide a combination of EP mapping and IGS functionalities, including the CARTO 3® system by Biosense Webster, Inc. of Irvine, Calif. Examples of catheters that are configured for use with an IGS system are disclosed in U.S. Patent No. 9,480,416, incorporated herein by reference. SUMMARY A medical probe can include electrodes configured to perform electrical ablation using IRE and/or thermal ablation while also being configured for sensing function such as sensing proximity to tissue and/or monitoring electrical signals within the cardiovascular system to identify aberrant conductive tissue sites that are responsible for an arrhythmia. When configured for thermal ablation, the electrodes have sufficient mass to carry electrical energy and provide thermal conduction and stability for thermal ablation. The electrodes can be oriented on an end effector assembly, such as a basket assembly, such that one side of an electrode is positioned to contact tissue and the opposite side is inhibited from contacting tissue. To enable both efficient delivery of energy as well as high sensitivity for ECG sensing an impedance reducing coating can be positioned on the tissue contacting side and an impedance increasing coating can be applied on the opposite side. When configured for IRE, the impedance increasing coating is configured to provide sufficient electrical 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. An example medical probe includes a shaft, a plurality of spines, and a plurality of electrodes. The shaft extends along a longitudinal axis. The plurality of spines exten