Architecture for high density mapping and ablation catheters using flexible circuit boards

Abstract

A catheter for ablating tissue by irreversible electroporation includes an electrode assembly including a flexible circuit having a distal central flexible circuit hub and a plurality of flexible circuit branches extending proximally from the hub portion, each of the flexible circuit branches at least partially defines an electrode assembly leg. The flex circuit further includes a distal ablation electrode including an ablation electrode hub portion and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a respective one of the flex circuit branches and terminating at a proximal end, each of the proximal ablation electrodes is located on a respective one of the flex circuit branches and has a distal end spaced from a proximal end of an adjacent radial segment of the distal ablation electrode.

Description

Technical Field

[0001] The present disclosure relates to medical systems and methods for ablating tissue within a patient. More specifically, the present disclosure relates to medical systems and methods for ablating tissue by electroporation. Background Art

[0002] Ablation procedures are used to treat many different conditions in patients. Ablation can be used to treat arrhythmias, benign tumors, cancerous tumors and to control bleeding during surgery. Generally, ablation is accomplished by thermal ablation techniques including radio-frequency (RF) ablation and cryoablation. In RF ablation, a probe is inserted into the patient and radio-frequency waves are transmitted through the probe to the surrounding tissue. The radio-frequency waves generate heat, which destroys the surrounding tissue and cauterizes blood vessels. In cryoablation, a hollow needle or cryoprobe is inserted into the patient and a cold thermally conductive fluid is circulated through the probe to freeze and kill the surrounding tissue. RF ablation and cryoablation techniques kill tissue indiscriminately by cell necrosis, which can damage or kill other healthy tissue, such as tissue in the esophagus, phrenic nerve cells and tissue in the coronary arteries.

[0003] Another ablation technique uses electroporation. In electroporation or electroosmosis, an electric field is applied to a cell to increase the permeability of the cell membrane. Electroporation can be reversible or irreversible, depending on the strength of the electric field. If electroporation is reversible, the increased permeability of the cell membrane can be used to introduce chemicals, pharmaceuticals and / or deoxyribonucleic acid (DNA) into the cell before the cell heals and recovers. If electroporation is irreversible, the affected cells are killed by apoptosis.

[0004] Irreversible electroporation can be used as a non-thermal ablation technique. In irreversible electroporation, short, high-voltage pulse trains are used to generate an electric field strong enough to kill cells by apoptosis. In the ablation of cardiac tissue, irreversible electroporation can be a safe and effective alternative to the indiscriminate killing of thermal ablation techniques such as RF ablation and cryoablation. Irreversible electroporation can be used to kill targeted tissue, such as cardiac tissue, by using an electric field strength and duration that kills the targeted tissue but does not permanently damage other cells or tissue, such as non-targeted myocardial tissue, red blood cells, vascular smooth muscle tissue, endothelial tissue and nerve cells. There is a continuing need for improved devices and methods for performing cardiac tissue ablation by irreversible electroporation. Summary of the Invention

[0005] In Example 1, a catheter for ablating cardiac tissue by irreversible electroporation, the catheter includes a tubular outer shaft having a proximal end and an opposite distal end, and an electrode assembly extending distally from the distal end of the outer shaft. The electrode assembly defines a central hub portion located distally and a plurality of struts, each strut including a distal portion extending from the central hub portion and a proximal portion attached to and constrained by the outer shaft. The electrode assembly includes a flexible circuit having a flexible circuit hub and a plurality of flexible circuit branches extending proximally from the flexible circuit hub. The flexible circuit further includes: a distal ablation electrode including an ablation electrode hub portion located on the flexible circuit hub and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a corresponding one of the flexible circuit branches and terminating at the proximal end; and a plurality of proximal ablation electrodes, each of the proximal ablation electrodes being located on a corresponding one of the flexible circuit branches and having a distal end spaced apart from the proximal end of an adjacent radial segment of the distal ablation electrode.

[0006] In Example 2, the catheter according to Example 1 further includes a plurality of strut sensing electrodes located on each strut.

[0007] In Example 3, the catheter according to Example 2, wherein the most distal strut sensing electrode on each strut is disposed within the periphery of each of the radial segments of the distal ablation electrode and is electrically isolated from the distal ablation electrode.

[0008] In Example 4, the catheter according to Example 2 or Example 3, wherein one or more of the plurality of strut sensing electrodes are disposed within the periphery of each of the proximal ablation electrodes and are electrically isolated therefrom.

[0009] In Example 5, the catheter according to any one of Examples 1-4, wherein the proximal end of each radial segment has a semi-circular shape.

[0010] In Example 6, the catheter according to any one of Examples 1-5, wherein the distal end of each proximal ablation electrode has a semi-circular shape.

[0011] In Example 7, the catheter according to any one of Examples 1-6, wherein each of the proximal ablation electrodes includes one or more proximal ablation electrode holes formed therein, and wherein one of the strut sensing electrodes is disposed in a corresponding one of the proximal ablation electrode holes.

[0012] In Example 8, the catheter according to Example 7, wherein each proximal ablation electrode hole is bounded by the corresponding inner circumferential surface of the proximal ablation electrode, and wherein the outer circumferential surface of each strut sensing electrode is spaced apart from the corresponding inner circumferential surface of the proximal ablation electrode.

[0013] In Example 9, the catheter according to any one of Examples 3-8, wherein each radial segment of the distal ablation electrode includes a proximal portion in which a radial segment hole is formed, and wherein each of the most distal strut sensing electrodes is disposed within a respective one of the radial segment holes.

[0014] In Example 10, the catheter according to Example 9, wherein each radial segment hole is bounded by the respective inner circumferential surface of the radial segment, and wherein the outer circumferential surface of each of the most distal strut sensing electrodes is spaced apart from the respective inner circumferential surface of the radial segment.

[0015] In Example 11, the catheter according to any one of Examples 9 or 10, wherein each radial segment of the radial segments has a distal portion opposite the proximal portion, and the proximal portion has a greater transverse width than the distal portion.

[0016] In Example 12, the catheter according to any one of Examples 1-11, further comprising a hub sensing electrode centered on the central hub portion of the electrode assembly.

[0017] In Example 13, the catheter according to any one of Examples 1-12, wherein each strut has a transverse edge that has an atraumatic shape.

[0018] In Example 14, the catheter according to any one of Examples 1-13, further comprising a central post that extends distally from the distal end of the tubular shaft and extends into the internal space defined by the electrode assembly when the electrode assembly is in the expanded configuration, the central post including a reference electrode.

[0019] In Example 15, the catheter according to any one of Examples 1-14, wherein the electrode assembly further comprises a support member having a support member hub and a plurality of support member branches extending proximally from the support member hub, wherein the flexible circuit hub is disposed above the support member hub, and each of the flexible circuit branches of the flexible circuit is disposed above a respective one of the support member branches.

[0020] Example 16 is a catheter for ablating cardiac tissue by irreversible electroporation. The catheter includes a tubular outer shaft having a proximal end and an opposite distal end, and an electrode assembly extending distally from the distal end of the outer shaft. The electrode assembly defines a central hub portion located distally and a plurality of struts. Each strut includes a distal portion extending from the central hub portion and a proximal portion attached to and constrained by the outer shaft. The electrode assembly includes a support member and a flexible circuit. The support member has a support member hub and a plurality of support member branches extending proximally from the support member hub. The flexible circuit is attached to the outer surface of the support member and has a flexible circuit hub disposed above the support member hub, and a plurality of flexible circuit branches. Each of the flexible circuit branches is disposed above a corresponding one of the support member branches. The flexible circuit further includes a distal ablation electrode and a plurality of proximal ablation electrodes. The distal ablation electrode includes an ablation electrode hub portion located on the flexible circuit hub, and a plurality of radial segments integrally formed with the ablation electrode hub portion. Each of the radial segments extends proximally along a portion of a corresponding one of the flexible circuit branches and terminates at the proximal end. Each of the proximal ablation electrodes is located on a corresponding one of the flexible circuit branches and has a distal end spaced apart from the proximal end of an adjacent radial segment of the distal ablation electrode.

[0021] In Example 17, the catheter according to Example 16, wherein the flexible circuit further includes a plurality of strut sensing electrodes located on each strut. The most distal strut sensing electrode on each strut is disposed within the periphery of each of the radial segments of the distal ablation electrode and is electrically isolated from the distal ablation electrode. And one or more of the plurality of strut sensing electrodes are disposed within the periphery of each of the proximal ablation electrodes and are electrically isolated therefrom.

[0022] In Example 18, the catheter according to Example 17, wherein the proximal end of each radial segment has a semi-circular shape.

[0023] In Example 19, the catheter according to Example 18, wherein the distal end of each proximal ablation electrode has a semi-circular shape.

[0024] In Example 20, the catheter according to Example 17, wherein each of the proximal ablation electrodes includes one or more proximal ablation electrode holes formed therein. And one of the strut sensing electrodes is disposed in a corresponding one of the proximal ablation electrode holes.

[0025] In Example 21, the catheter according to Example 20, wherein each proximal ablation electrode hole is bounded by the corresponding inner circumferential surface of the proximal ablation electrode. And the outer circumferential surface of each strut sensing electrode is spaced apart from the corresponding inner circumferential surface of the proximal ablation electrode.

[0026] In Example 22, a catheter according to Example 17, wherein each radial segment of the distal ablation electrodes includes a proximal portion in which a radial segment hole is formed, and wherein each of the most distal strut sensing electrodes is disposed within a respective one of the radial segment holes.

[0027] In Example 23, a catheter according to Example 22, wherein each radial segment hole is bounded by a respective inner circumferential surface of the radial segment, and wherein an outer circumferential surface of each of the most distal strut sensing electrodes is spaced apart from the respective inner circumferential surface of the radial segment.

[0028] In Example 24, a catheter according to Example 17, further comprising a hub sensing electrode centered on a central hub portion of the electrode assembly.

[0029] In Example 25, a catheter according to Example 17, further comprising a central post that extends distally from a distal end of the tubular shaft and extends into an internal space defined by the electrode assembly when the electrode assembly is in an expanded configuration, the central post including a reference electrode.

[0030] Example 26 is a catheter for ablating cardiac tissue by irreversible electroporation, the catheter including a tubular outer shaft having a proximal end and an opposite distal end, and an electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly defining a central hub portion located distally and a plurality of struts, each strut including a distal portion extending proximally from the central hub portion, and a proximal portion attached to and constrained by the outer shaft. The electrode assembly includes a support member and a flexible circuit. The support member is formed of a superelastic material and has a support member hub and a plurality of support member branches integrally formed with and extending proximally from the support member hub. The flexible circuit is attached to an outer surface of the support member and has a flexible circuit hub disposed above the support member hub, and a plurality of flexible circuit branches integrally formed with the flexible circuit hub, each of the flexible circuit branches being disposed above a respective one of the support member branches. The flexible circuit further includes a distal ablation electrode, a plurality of proximal ablation electrodes, and a plurality of strut sensing electrodes. The distal ablation electrode includes an ablation electrode hub portion located on the flexible circuit hub, and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a respective one of the flexible circuit branches. Each of the proximal ablation electrodes is located on a respective one of the flexible circuit branches. The plurality of strut sensing electrodes includes a plurality of distal strut sensing electrodes and one or more proximal strut sensing electrodes, each of the plurality of distal strut sensing electrodes being disposed within and electrically isolated from a respective one of the radial segments of the distal ablation electrode, and the one or more proximal strut sensing electrodes being disposed within and electrically isolated from each of the proximal ablation electrodes.

[0031] In Example 27, the catheter according to Example 26, wherein each of the proximal ablation electrodes has a proximal end and a distal end having a semi-circular shape, and wherein each of the radial segments has a proximal end having a semi-circular shape.

[0032] In Example 28, the catheter according to Example 26, wherein each of the proximal ablation electrodes includes one or more proximal ablation electrode holes formed therein, and wherein each of the proximal strut sensing electrodes is disposed in a respective one of the proximal ablation electrode holes.

[0033] In Example 29, the catheter according to Example 28, wherein each proximal ablation electrode hole is bounded by a respective inner circumferential surface of the proximal ablation electrode, and wherein an outer circumferential surface of each proximal strut sensing electrode is spaced apart from the respective inner circumferential surface of the proximal ablation electrode.

[0034] In Example 30, the catheter according to Example 26, wherein each of the radial segments of the distal ablation electrode includes a proximal portion in which a radial segment hole is formed, and wherein each of the distal strut sensing electrodes is disposed in a respective one of the radial segment holes.

[0035] In Example 31, the catheter according to Example 30, wherein each radial segment hole is bounded by a respective inner circumferential surface of the radial segment, and wherein an outer circumferential surface of each distal strut sensing electrode is spaced apart from the respective inner circumferential surface of the radial segment.

[0036] Example 32 is a catheter for ablating cardiac tissue by irreversible electroporation, the catheter including a tubular outer shaft having a proximal end and an opposite distal end and an electrode assembly extending distally from the distal end of the outer shaft. The electrode assembly includes a flexible circuit having a central flexible circuit hub located distally and a plurality of flexible circuit branches extending proximally from the hub portion, each of the flexible circuit branches at least partially defining an electrode assembly strut and including a proximal portion attached to and constrained by the outer shaft. The flexible circuit further includes a distal ablation electrode and a plurality of proximal ablation electrodes. The distal ablation electrode includes an ablation electrode hub portion located on the flexible circuit hub and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a respective one of the flexible circuit branches and terminating at a proximal end. Each of the proximal ablation electrodes is located on a respective one of the flexible circuit branches and has a distal end spaced apart from the proximal end of an adjacent radial segment of the distal ablation electrode.

[0037] In Example 33, the catheter according to Example 32, wherein the proximal end of each radial segment has a semi-circular shape, and wherein the distal end of each proximal ablation electrode has a semi-circular shape.

[0038] In Example 34, the catheter according to Example 33, wherein the flexible circuit further includes a plurality of strut sensing electrodes located on each strut, wherein the outermost strut sensing electrode on each strut is disposed within the periphery of each of the radial segments of the distal ablation electrode and is electrically isolated from the distal ablation electrode, and wherein one or more of the plurality of strut sensing electrodes are disposed within the periphery of each of the proximal ablation electrodes and are electrically isolated therefrom.

[0039] In Example 35, the catheter according to Example 34, wherein the flexible circuit further includes a hub sensing electrode centered on the flexible circuit hub.

[0040] While multiple embodiments have been disclosed, other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which illustrates and describes illustrative embodiments of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram showing an exemplary clinical device for treating a patient and treating the patient's heart using an electrophysiology system according to an embodiment of the subject matter of the present disclosure.

[0042] Figure 2A is for use with an electrophysiology system according to an embodiment of the subject matter of the present disclosure Figure 1 perspective view of the distal portion of a strut catheter.

[0043] Figures 2B - 2C is a partial plan view of an electrode assembly of a strut catheter shown in a two-dimensional manner according to an embodiment of the subject matter of the present disclosure.

[0044] Figure 2D is according to an embodiment of the subject matter of the present disclosure Figure 2B magnified plan view of a portion of a strut of the electrode assembly shown in.

[0045] Figure 2E is according to an embodiment of the subject matter of the present disclosure Figure 2B schematic cross-sectional view of a strut of the electrode assembly.

[0046] Figures 2F - 2G is according to an embodiment of the subject matter of the present disclosure Figure 2A perspective view of a portion of the distal portion of the catheter.

[0047] Figures 3 - 6 is for use with a catheter according to an embodiment of the subject matter of the present disclosure Figure 1 plan view of an alternative electrode assembly.

[0048] Figures 7A - 7D is a schematic cross-sectional view of an alternative strut configuration for a catheter Figure 1 in accordance with an embodiment of the subject matter of the present disclosure.

[0049] While the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. However, the intention is not to limit the present disclosure to the particular embodiments described. Rather, the present disclosure is intended to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims. Detailed Description

[0050] For purposes of facilitating an understanding of the principles of the present disclosure, reference is now made to the examples illustrated in the drawings, which are described below. The illustrated examples disclosed herein are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed in the following detailed description. Rather, the exemplary embodiments are chosen and described so that others skilled in the art may utilize their teachings. Having multiple (e.g., all) features from a given example used across all examples does not exceed the scope of the present disclosure. Accordingly, no single drawing should be construed as having any dependency or requirement related to any single component or combination of components illustrated therein. Additionally, in the examples, the various components depicted in a given drawing may be integrated with various components (and / or components not depicted) among those depicted in other drawings, all of which are considered to be within the scope of the present disclosure.

[0051] The terms “coupled,” “coupling,” “connected,” “attached,” and the like, along with their variants, are used to include arrangements in which two or more components are in direct physical contact and arrangements in which two or more components are not in direct physical contact but still cooperate or interact with each other (e.g., components are “coupled” via at least a third component).

[0052] Throughout the present disclosure and in the claims, numerical terms, such as first and second, are used to refer to various components or features. This use is not intended to denote an order of the components or features. Rather, the numerical terms are used to assist the reader in identifying the components or features being referred to and should not be construed narrowly as providing a particular order of the components or features.

[0053] Figure 1FIG. 0 is a schematic diagram showing an exemplary clinical device 10 for treating a patient 20 and treating the heart 30 of the patient 20 using an electrophysiology system 50 in accordance with an embodiment of the subject matter of the present disclosure. The electrophysiology system 50 includes an electroporation catheter system 60 and an electro-anatomical mapping (EAM) system 70, which includes a positioning field generator 80, a mapping and navigation controller 90, and a display 92. In addition, the clinical device 10 includes additional devices such as an imaging device 94 (represented by a C-arm) and various controller elements, such as a foot controller 96, which is configured to allow an operator to control various aspects of the electrophysiology system 50. As will be understood by those skilled in the art, the clinical device 10 may have other components and arrangements of components not shown in Figure 1 FIG.

[0054] The electroporation catheter system 60 includes an electroporation catheter 100 having a proximal portion 102 and a distal portion 105, an introducer sheath 110, and an electroporation console 130. Additionally, the electroporation catheter system 60 includes various connection elements, such as cables, umbilicals, and the like, which operate to functionally connect the components of the electroporation catheter system 60 to each other and to the components of the EAM system 70. This arrangement of connection elements is not critical to the present disclosure, and those skilled in the art will recognize that the various components described herein may be interconnected in a variety of ways.

[0055] In an embodiment, the introducer sheath 110 is operable to provide a delivery catheter through which the electroporation catheter 100, particularly all or a portion of its distal portion 105, can be deployed to a specific target site within the patient's heart 30.

[0056] In an embodiment, the electroporation catheter system 60 is configured to deliver electric field energy to targeted tissue in the patient's heart 30 to produce apoptosis, rendering the tissue unable to conduct electrical signals.

[0057] The electroporation console 130 is configured to control the functional aspects of the electroporation catheter system 60. In an embodiment, the electroporation console 130 includes one or more controllers, microprocessors, and / or computers that execute code in a memory to control and / or perform the functional aspects of the electroporation catheter system 60. In an embodiment, the memory can be part of one or more controllers, microprocessors, and / or computers, and / or part of a memory capacity accessible via a network (such as the World Wide Web). In an embodiment, the electroporation console 130 includes pulse generator hardware, software, and / or firmware configured to generate electrical pulses in a predefined waveform that are transmitted to electrodes on the electroporation catheter 100 to create an electric field sufficient to achieve a desired clinical effect, particularly ablation of target tissue by irreversible electroporation. In an embodiment, the electroporation console 130 is capable of delivering pulse waveforms to the electroporation catheter 100 in a monopolar or bipolar operating mode, as will be described in further detail herein.

[0058] The EAM system 70 is operable to track the position of the various functional components of the electroporation catheter system 60 and generate high-fidelity three-dimensional anatomical and electroanatomical maps of the cardiac chamber of interest. In an embodiment, the EAM system 70 can be the RHYTHMIA TM HDx mapping system sold by Boston Scientific Corporation. Additionally, in an embodiment, the mapping and navigation controller 90 of the EAM system 70 includes one or more controllers, microprocessors, and / or computers that execute code in a memory to control and / or perform the functional aspects of the EAM system 70, where in an embodiment, the memory can be part of one or more controllers, microprocessors, and / or computers, and / or part of a memory capacity accessible via a network (such as the World Wide Web).

[0059] As will be understood by those skilled in the art, the depiction of the Figure 1 electrophysiology system 50 shown is intended to provide an overall overview of the various components of the system 50 and is not in any way intended to imply that the present disclosure is limited to any collection of components or arrangement of components. For example, those skilled in the art will readily recognize that additional hardware components, such as splice boxes, workstations, and the like, can and most likely will be included in the electrophysiology system 50.

[0060] The EAM system 70 generates a positioning field via a field generator 80 to define a positioning volume with respect to the heart 30, and one or more position sensors or sensing elements on one or more tracked devices (such as the electroporation catheter 100) generate outputs that can be processed by the mapping and navigation controller 90 to track the position of the sensors, and thus track the corresponding devices within the positioning volume. In the illustrated embodiment, magnetic tracking technology is used to accomplish device tracking, whereby the field generator 80 is a magnetic field generator that generates a magnetic field defining the positioning volume, and the position sensor on the tracked device is a magnetic field sensor.

[0061] In other embodiments, impedance tracking methods may be employed to track the positions of various devices. In such embodiments, the positioning field is an electric field generated, for example, by an external field generator arrangement (such as surface electrodes), by an in-vivo or intracardiac device (such as an intracardiac catheter), or both. In these embodiments, the position sensing element may constitute an electrode on the tracked device that generates an output received and processed by the mapping and navigation controller 90 to track the positions of the various position sensing electrodes within the positioning volume.

[0062] In an embodiment, the EAM system 70 is equipped for both magnetic and impedance tracking capabilities. In such embodiments, the impedance tracking accuracy can, in some cases, be enhanced by first using a probe equipped with a magnetic position sensor to create a map of the electric field induced by an electric field generator within the cardiac chamber of interest, using the aforementioned RHYTHMIA HDx TM mapping system is possible. An exemplary probe is the INTELLAMAP ORION TM mapping catheter sold by Boston Scientific Corporation.

[0063] Regardless of the tracking method employed, the EAM system 70 utilizes the position information for the various tracked devices, along with the electrocardiographic activity obtained, for example, by the electroporation catheter 100 or another catheter or probe equipped with sensing electrodes, to generate and display via the display 92 a detailed three-dimensional geometric anatomical map or representation of the cardiac chamber and an electroanatomical map in which the electrocardiographic activity of interest is superimposed on the geometric anatomy. In addition, the EAM system 70 can generate graphical representations of the various tracked devices within the geometric anatomical map and / or the electroanatomical map.

[0064] Embodiments of the present disclosure provide systems, devices, and methods for selectively and rapidly applying pulsed electric fields to ablate tissue by irreversible electroporation. Generally, the systems, devices, and methods described herein can be used to generate large electric field magnitudes at a desired region of interest and reduce peak electric field values elsewhere, in order to reduce unnecessary tissue damage and arcing. An irreversible electroporation system as described herein can include a signal generator and a processor configured to apply one or more voltage pulse waveforms to a selected set of electrodes of an ablation device to deliver energy to a region of interest (e.g., ablation energy for a tissue mass at a pulmonary vein ostium or sinus). The pulse waveforms disclosed herein can facilitate therapeutic treatment of various cardiac arrhythmias (e.g., atrial fibrillation). To deliver the pulse waveforms generated by the signal generator, one or more electrodes of the ablation device can have insulated electrical leads configured to maintain a voltage potential of about several hundred volts to several thousand volts. The electrodes can be independently addressable such that each electrode can be controlled (e.g., deliver energy) independent of any other electrode of the device. In this manner, the electrodes can synergistically deliver different energy waveforms at different timings for electroporation of tissue.

[0065] The pulse waveforms for electroporation energy delivery as disclosed herein can enhance the safety, efficiency, and effectiveness of energy delivery to tissue by reducing the electric field threshold associated with irreversible electroporation, thereby resulting in a more effective ablation lesion and a reduction in the total energy delivered. In some embodiments, the voltage pulse waveforms disclosed herein can be layered and have a nested structure. For example, the pulse waveform can include a layered grouping of pulses with associated time scales. In some embodiments, the methods, systems, and devices disclosed herein can include one or more of the methods, systems, and devices described in International Application Serial No. PCT / US2016 / 057664, filed October 19, 2016, titled "SYSTEMS, APPARATUSES AND METHODS FOR DELIVERY OF ABLATIVE ENERGY TO TISSUE", the content of which is incorporated herein by reference in its entirety.

[0066] Figure 2A is a partial perspective view illustration of an electroporation catheter 200 having a distal portion 205 of the catheter in accordance with an embodiment of the present disclosure. The electroporation catheter 200 corresponds to that regarding Figure 1The described electroporation catheter 100. The electroporation catheter 200 has: a tubular outer shaft 208 having a distal shaft end 209; and an electrode assembly 210 extending distally from the distal end 209 of the outer shaft 208. In an embodiment, the electrode assembly 210 is configured to self-expand from a folded configuration when constrained within a delivery sheath to a predefined expanded configuration defining an internal space 212. As will be explained in more detail herein, the electrode assembly includes a plurality of ablation electrodes configured to receive a pulsed electrical signal / waveform ( Figure 1 ) from an electroporation console 130, thereby creating a pulsed electric field sufficient to ablate target tissue via irreversible electroporation. Additionally, the electrode assembly 210 further includes a plurality of mapping and sensing electrodes configured, among other things, to sense electrocardiogram signals, localize the electrode assembly 210 within the patient's anatomy (e.g., via Figure 1 's EAM system 70), and determine proximity to target tissue within the anatomy.

[0067] Generally speaking, compared to the relatively large-diameter circumferential lesions created during pulmonary vein isolation procedures, the electrode assembly 210 and other electrode assembly embodiments described herein within the scope of the present disclosure are primarily designed to create relatively local ablation lesions (i.e., focal lesions). However, those skilled in the art will understand that the teachings of the present disclosure can be readily adapted to catheters capable of creating large-diameter circumferential lesions. The designs of the various electrode assembly embodiments described herein can provide clinicians with a wide range of capabilities for monopolar and bipolar focal pulse field ablation of cardiac tissue, combined with the ability to perform local (i.e., at the location of delivery of the pulse field ablation energy), high-fidelity sensing (e.g., for lesion or conduction block assessment, tissue contact determination, and the like) of cardiac tissue.

[0068] Figures 2B - 2C is a partial plan view of the electrode assembly 210 of the electroporation catheter 200, shown in two dimensions to illustrate the layout of the electrode assembly 210. Referring together to Figures 2A - 2C, in the illustrated embodiment, the electrode assembly 210 as a whole has a distal central hub portion 214 and a plurality of struts 216A - 216F extending proximally from the central hub portion 214. As further shown, each respective strut 216A - 216F has a distal portion 217A - 217F, a proximal portion 218A - 218F, and an intermediate portion 219A - 219F extending between the distal portion 217A - 217F and the proximal portion 218A - 218F. As shown, each of the proximal portions 218A - 218F is attached to and constrained by the distal end 209 of the outer shaft 202. As further shown, in the illustrated embodiment, the intermediate portion 219A - 219F of each strut 216A - 216F has a lateral width greater than that of each of the corresponding proximal portion 218A - 218F and distal portion 217A - 217F. In an embodiment, the specific geometry of the struts 216A - 216F and associated components (such as ablation and mapping electrodes) is optimized to provide desired mechanical and therapeutic / diagnostic capabilities.

[0069] In the illustrated embodiment, the struts 216A - 216F are composed of a support member 220 and a flexible circuit 222, and the flexible circuit 222 is fixed to and disposed above the outer surface of the support member 222. The support member 220 serves, among other things, as the main structural support of the electrode assembly 210 and thus mainly defines the mechanical characteristics of the electrode assembly 210. In an embodiment, the support member 220 is formed of a superelastic material (metal or polymer) to provide the desired mechanical / structural properties to the electrode assembly 210. In an embodiment, the support member 220 is formed of a superelastic metal alloy, for example, a nitinol alloy.

[0070] The support member 220 includes a support member hub 224 and a plurality of support member branches 226A - 226F. In an embodiment, the support member branches 226A - 226F are integrally formed with the support member hub 224 and extend proximally from the support member hub 224. For example, the entire support member 200 can be cut from a single piece of material using conventional manufacturing techniques. This integrated structure provides robust structural properties, such as selective flexibility and enhanced fatigue characteristics, particularly in regions that are subject to relatively high stresses during the manufacture and use of the electroporation catheter 200. Due to the shape - memory properties of the material, forming the support member 220 from a superelastic material such as nitinol alloy facilitates configuring the support member 220 to assume its desired unconstrained shape, as Figure 2A shown, while providing sufficient flexibility necessary for folding the electrode assembly 210 within the delivery sheath. In an embodiment, the support member branches 226A - 226F can be selectively configured along their lengths to tune the mechanical characteristics of the electrode assembly 210.

[0071] The flexible circuit 222 includes a flexible circuit hub 230 and a plurality of flexible circuit branches 234A - 234F. In an embodiment, the flexible circuit hub 230 is disposed above and fixed to the support member hub 224. In an embodiment, the flexible circuit branches 234A - 234F are integrally formed with the flexible circuit hub 230, and each of the flexible circuit branches 234A - 234F is disposed above and fixed to a corresponding one of the support member branches 226A - 226F. The flexible circuit 222 includes a layered structure that includes one or more dielectric substrate layers and conductive traces formed thereon. Similar to the support member 220, the integrated structure of the flexible circuit 222 enhances its structural properties, for example, by minimizing joints or other discontinuities in regions that will be subjected to relatively high stress during use.

[0072] As shown, the flexible circuit 222 includes a distal ablation electrode 238 having a distal ablation electrode hub portion 240 and a plurality of radial segments 242A - 242F. In the illustrated embodiment, the distal ablation electrode hub portion 240 is located on the flexible circuit hub 230. Additionally, the radial segments 242A - 242F are integrally formed with the distal ablation electrode hub portion 240. Each of the radial segments 242A - 242F extends proximally along a portion of a corresponding one of the flexible circuit branches 234A - 234F. The flexible circuit 222 further includes a plurality of proximal ablation electrodes 244A - 244F. As shown, each of the proximal ablation electrodes 244A - 244F is located on a corresponding one of the flexible circuit branches 234A - 234F.

[0073] As further shown, the flexible circuit 222 includes a plurality of strut sensing electrodes 250. In the illustrated embodiment, each of the strut sensing electrodes 250 is disposed within the periphery of one of the proximal ablation electrodes 244A - 244F or one of the radial segments 242A - 242F of the distal ablation electrode 238. For example, as shown, each of the most distal strut sensing electrodes 250 is disposed within the periphery of a corresponding one of the radial segments 242A - 242F of the distal ablation electrode 238 and is electrically isolated from the distal ablation electrode 238. Additionally, a plurality of more proximal strut sensing electrodes 250 are included, which are disposed along and within the periphery of a corresponding one of each of the proximal ablation electrodes 244A - 244F and are electrically isolated therefrom.

[0074] In some embodiments, the structural function of the support member 220 can be provided by a properly designed flexible circuit 222. Thus, although the electrode assembly 210 is described in detail as including the support member 220 as a main structural member, in other embodiments the support member 220 can be omitted entirely and the corresponding function can be provided by the flexible circuit 222.

[0075] In a particularly illustrated embodiment, the electroporation catheter 200 includes a central column 258 extending distally from the distal end 209 of the outer shaft 202. As shown, the central column 258 extends partially into the internal space 212 and includes a column electrode 260. As further shown, in a particularly illustrated embodiment, an optional flush lumen 261 is supported by the central column 258. In an embodiment, the central column 258 may house additional components. For example, in an embodiment, a magnetic navigation sensor (not shown) may be partially or fully disposed within the central column 258. However, in other embodiments, such sensors may be located elsewhere on the electroporation catheter 200 (e.g., within the outer shaft 202). In the illustrated embodiment, the electrode assembly 210 further includes a hub sensing electrode 264 centrally located on the flexible circuit hub 230.

[0076] The column electrode 260 may provide a number of functional advantages. In one example, the column electrode 260 may operate as a reference for a unipolar electrogram, replacing the reliance on surface ECG patch electrodes as otherwise known in the art. The position of the column electrode 260 for this purpose positions the reference electrode closer to the tissue being sensed than may be possible using conventional surface ECG methods, which may advantageously minimize far-field noise and provide a clearer unipolar electrogram than may be provided using surface ECG electrodes. The column electrode 260 may also be operable to sense and measure other electrical parameters, e.g., the voltage between it and an ablation electrode or other sensing electrodes on the electrode assembly 210, thereby providing in some examples data that can be used to determine the shape of the electrode assembly during use (including when deformed by forces applied by the heart wall), and displaying the shape information via the EAM system 70( Figure 1 )).

[0077] In an embodiment, the hub sensing electrode 264 allows for tissue surface mapping in a "forward" manner, eliminating the need to manipulate the electrode assembly 210 to place the strut sensing electrodes 250 against or near the tissue to be mapped. The bipolar sensing capability is further enhanced by providing six additional bipolars in the illustrated embodiment when paired with any of the most distal strut sensing electrodes 250, including the hub sensing electrode 264.

[0078] Specifically referring to Figure 2C, each of the radial segments 242A - 242F of the distal ablation electrode 238 includes a proximal portion 266A - 266F having a proximal end 268A - 268F, and a distal portion 270A - 270F extending from the distal ablation electrode hub portion 240. As further shown, a radial segment hole 272 is formed in each of the proximal portions 266A - 266F, and a respective one of the most distal strut sensing electrodes 250 is disposed within each of the radial segment holes 272. In the illustrated embodiment, each of the proximal portions 266A - 266F has a transverse width greater than that of the corresponding distal portion 270A - 270F, at least partially accommodating the most distal strut sensing electrodes 250.

[0079] Figure 2D is an enlarged plan view of a portion of strut 216A according to an embodiment of the present disclosure. Figure 2D The structural features shown therein represent struts 216A - 216F. As shown, the proximal ablation electrode 244A has a proximal end 274A and a distal end 276A. In addition, the proximal ablation electrode 244A has a length L defined as the distance between the proximal end 274A and the distal end 276A SE . The proximal ablation electrode 244A also has a width W SE . In an embodiment, the width W SE may be substantially constant along the length of the proximal ablation electrode 244A, or alternatively, may vary along the length. Generally, the width W SE and the length L SE are sized to provide desired electrical characteristics for a particular clinical application. In an embodiment, the width W SE may range from about 0.25 millimeters to 2 millimeters, and the length L SE may range from about 3 millimeters to 13 millimeters.

[0080] As further shown, the proximal ablation electrode 244A includes a plurality of proximal ablation electrode holes 278, and one of the strut sensing electrodes 250 is disposed within each of the proximal ablation electrode holes 278.

[0081] In addition, in the illustrated embodiment, the proximal end 268A of the radial segment 242A of the distal ablation electrode 238 has a semi-circular shape and is spaced a distance D from the distal end 276A of the proximal ablation electrode 244A, which also has a semi-circular shape. In an embodiment, the spacing D can range from about 0.25 millimeters to 3 millimeters. In one embodiment, the spacing D is about 0.40 millimeters. In an embodiment, the spacing D can be selectively customized to minimize the current shunted between the distal ablation electrode 238 and the proximal ablation electrodes 244A - 244F. The spacing D can also minimize or even eliminate undesirable ablation effects, such as local spark / arc or bubble formation. In some embodiments, the spacing D also facilitates bipolar ablation by configuring one or more of the distal ablation electrode 238 and the proximal ablation electrodes 244A - 244F to have opposite polarities (e.g., one is configured as an anode and the other as a cathode). The semi-circular shapes of the proximal end 268A of the radial segment 242A of the distal ablation electrode 238 and the distal end 276A of the proximal ablation electrode 244A also have unexpected advantages. In particular, this semi-circular profile operates to maximize the current distribution along the electrode edges. In general, the radius of the semi-circular shape can be selected to be as large as possible within the constraints imposed by the width W of the ablation electrode SE imposed.

[0082] The inventors of the present disclosure have found that the spacing between the proximal end 268A of the distal ablation electrode radial segment 242A and the distal end 276A of the proximal ablation electrode provides an electric field that is significantly more effective than the electric field generated by a continuous electrode structure without such spacing. For example, separating the distal and proximal ablation electrodes allows for selective activation of certain ablation electrodes. In addition, separating the distal ablation electrode 238 from the proximal ablation electrodes 244A - 244F provides a local ablation pad with a relatively small surface area, which concentrates the local current density during ablation and minimizes the energy that would otherwise be shunted away by the blood pool (which is known to have a relatively low impedance compared to the target tissue).

[0083] Figure 2E along Figure 2D is a schematic cross-sectional view of the strut 216A taken along line 2E - 2E in, showing an exemplary configuration of the flexible circuit branch 234A. As Figure 2E shown, the strut 216A includes the support member branch 226A and the flexible circuit branch 234A is disposed thereon. As further shown, the flexible circuit branch 234A includes a layered structure, which can be typical of flexible circuits for use in medical device electrode assemblies, except as specifically distinguished herein. In Figure 2EIn the specific embodiment shown, the flexible circuit branch 234A includes a dielectric base layer 280A disposed above the support member branch 226A, an optional inner flexible adhesive layer 282A above the base layer 280A, a conductive trace layer 284A (if present) above the adhesive layer 282A, and a dielectric upper layer 286A above the conductive trace layer 284A. The dielectric materials selected for layers 280A and 286A can be any conventional materials suitable for flexible circuits for medical devices, such as polyamides. It should be emphasized that the present disclosure is not limited to Figure 2E the specific flexible circuit stack arrangement shown, and those skilled in the art will readily understand alternative arrangements that can be utilized.

[0084] As Figure 2E Further shown, the proximal ablation electrode 244A and the strut sensing electrode 250 are disposed above the upper layer 286A. In an embodiment, the electrodes 244A and 250 can have a coating of a suitable biocompatible metal, such as gold. In an embodiment, the outer surfaces of the electrodes 244A and 250 can be treated to provide the electrical properties desired for a particular clinical application.

[0085] As Figure 2E shown, the proximal ablation electrode aperture 278 is bounded by the inner peripheral surface 288 of the proximal ablation electrode 244A, and the outer peripheral surface 290 of the strut sensing electrode 250 is spaced from the inner peripheral surface 288 of the proximal ablation electrode 244A by a gap G. Conventionally, those skilled in the art would expect a dielectric material to be disposed between the outer peripheral surface 290 and the inner peripheral surface 288 of the proximal ablation electrode 244A in order to minimize potential undesirable effects, such as bubble formation that may result from arcing or edge effects at the periphery of the proximal ablation electrode 244A when a pulse waveform is delivered to the proximal ablation electrode 244A. However, the inventors of the present disclosure have found that by providing a gap G between the outer peripheral surfaces 290, the strut sensing electrode 250 is spaced from the inner peripheral surface 288 of the proximal ablation electrode 244A, and the tendency to form bubbles in the blood pool is significantly reduced compared to an arrangement in which a dielectric material is disposed in this region. These advantageous results can be enhanced by selectively customizing the size of the gap G. In an embodiment, the gap G can range from about 0.050 millimeters to 0.50 millimeters. In one embodiment, the gap G is about 0.50 millimeters.

[0086] Figures 2F - 2G is a perspective illustration of a portion of the distal portion 205 of an electroporation catheter 200 according to an embodiment of the subject matter of the present disclosure, which illustrates exemplary structural features for connecting an electrode assembly 210 to a shaft 202 (see Figure 2A ). As shown, the electroporation catheter 200 includes a transition member 292 fixed within the outer shaft 202 ( Figure 2A) and includes various positioning features, such as slots 294 for positioning various struts and connecting various struts to the shaft 202 and for accommodating the connection of the electrical conductor lines 296 to the respective flexible circuit branches. It should be emphasized that Figure 2F and Figure 2G the detailed arrangements shown in

[0087] are merely exemplary and are in no way intended to limit the scope of the present disclosure. Figure 1 In various embodiments, each of the respective proximal ablation electrodes 244A - 244F, distal ablation electrode 238, strut sensing electrodes 250, and hub sensing electrode 264 is electrically connected to the control system of the electroporation console 130 (

[0088] ) and can be individually addressed to provide a wide range of ablation and sensing modes, such as monopolar and bipolar modes. During monopolar ablation operation, the ablation electrodes, a group of ablation electrodes, or all of the ablation electrodes on the electrode assembly 210 are electrically coupled together and are configured to operate with one polarity, while the electrodes located elsewhere (e.g., a dispersive electrode typically on the patient's back, buttocks, or other suitable anatomical location, or an electrode on a different catheter or probe outside the heart chamber where the electrode assembly 210 is located) are configured to operate with the opposite polarity. In one example, the distal ablation electrode 238 and all of the proximal ablation electrodes 244A - 244F are configured to act together electrically as an anode or a cathode, and the extracorporeal dispersive electrode on the back patch is configured as the other of the cathode or anode. In other examples, the selected proximal ablation electrodes and optionally the distal ablation electrode 238 can be configured to operate together as an anode or a cathode, while the extracorporeal dispersive electrode is configured as the other of the cathode or anode. The foregoing examples can advantageously allow for selective manipulation of the resulting electric field to optimize electroporation effectiveness based on the relative orientation of the ablation assembly 210 and the target tissue. Those skilled in the art will readily recognize the wide range of monopolar ablation electrode configurations available.

[0089] In a similar manner, as will be appreciated by those skilled in the art, any one of the strut sensing electrodes 250, column reference electrodes 260, or hub sensing electrodes 264 can also be individually addressed for bipolar sensing and mapping any number of combinations. Additionally, in embodiments, the aforementioned individual addressability allows any one of the strut sensing electrodes and / or hub sensing electrodes 264 to be configured by the control system as an ablation electrode to cooperate with any one of the distal ablation electrode 238 and the proximal ablation electrodes 244A - 244F in monopolar or bipolar mode.

[0090] Figures 3 - 6 is a layout diagram of an alternative electrode assembly for use with a catheter according to an embodiment of the subject matter of the present disclosure. Figure 1 for a catheter. Figure 3 Shows a portion of an electrode assembly 310 that is substantially similar to the electrode assembly 210 and includes a central hub portion 314, a plurality of struts 316A - 316F, and a flexible circuit 322. Figure 3 The embodiment of differs from the electrode assembly 210 in that the proximal end 368 of each distal ablation electrode radial segment 342F - 342F is generally linear (i.e., not semi - circular), and the distal end 376 of each proximal ablation electrode 344A - 344F is also generally linear, such that the opposing surfaces of the proximal end 368 of each radial segment 342A - 342F and the opposing distal end of the corresponding proximal ablation electrode 344A - 344F are generally parallel to each other.

[0091] Figure 4 Shows a portion of an electrode assembly 410 that includes a central hub portion 414, a plurality of struts 416A - 416F, and a flexible circuit 422. As will be appreciated, the electrode assembly 410 also includes a support member (not shown) having a configuration substantially the same as the support member 220 of the electrode assembly 210. Figure 4 The embodiment of differs from the electrode assembly 210 in that the proximal end 468 of each distal ablation electrode radial segment 442A - 442F terminates distally at and is spaced from the most distal strut sensing electrode 450 on each strut.

[0092] Figure 5 Shows a portion of an electrode assembly 510 that includes a central hub portion 514, a plurality of struts 516A - 516F, and a flexible circuit 522. As will be appreciated, the electrode assembly 510 also includes a support member (not shown) having a configuration substantially the same as the support member 220 of the electrode assembly 210. The flexible circuit 522 differs from those previously described in that it does not include a distal ablation electrode, and the most distal strut sensing electrode 548 on each strut is located within the periphery of the corresponding proximal ablation electrodes 544A - 544F.

[0093] Figure 6Shows a portion of an electrode assembly 610 including a central hub portion 614, a plurality of struts 616A - 616F, and a flexible circuit 622. As further shown, the flexible circuit 622 includes a flexible circuit hub 630 and a plurality of flexible circuit branches 634A - 634F. As will be understood, the electrode assembly 610 also includes a support member (not shown) having a configuration substantially the same as the support member 620 of the electrode assembly 610.

[0094] As further shown, the flexible circuit 622 also includes, on each of the struts 616A - 616F, a series of alternating proximal ablation electrodes 644 and strut sensing electrodes 650 spaced apart from each other, i.e., no strut sensing electrode 650 is disposed within the periphery of any one of any of the proximal ablation electrodes 644. Additionally, in the illustrated embodiment, the flexible circuit 622 does not include a distal ablation electrode, although a distal ablation electrode may be included in other embodiments.

[0095] As discussed for the electrode assembly 210, in the electrode assemblies 310, 410, 510, and 610, all of the illustrated ablation and sensing electrodes can be individually addressed by a control system, thus providing a wide range of monopolar or bipolar ablation and monopolar or bipolar sensing capabilities. Similarly, any one or all of the various sensing electrodes can be configured to operate as ablation electrodes when a given clinical procedure is desired.

[0096] In the embodiments described and illustrated herein, each of the ablation assemblies has six struts. However, it should be emphasized that this is for illustrative purposes, and thus those skilled in the art will readily recognize that for a given clinical application, more or fewer than six struts may be included.

[0097] Figures 7A - 7D Is a schematic cross - sectional view of an alternative strut configuration that can be used for any catheter electrode assembly described herein. Generally, Figures 7A - 7D The embodiments of are configured to be substantially non - invasive, e.g., without relatively sharp edges.

[0098] Figure 7A Shows a strut 716A of a catheter according to an embodiment of the subject matter of the present disclosure. As shown, the strut 716A includes a support member 720 and a flexible circuit 722 disposed above and fixed to the support member 720. As will be understood, the support member 720 can correspond to that associated with Figure 1 Figures 2A - 2G ​The support member 220 described in the embodiments. As shown, the support member 720 has a generally oblong cross-sectional shape such that it has opposing lateral sides 720A, 720B that are generally arcuate or semi-circular in shape. In an embodiment, the lateral sides 720A, 720B can be formed by any number of manufacturing techniques known in the art, such as by machining or etching a flat portion of a material.

[0099] The strut 716A includes a flexible polymer layer 725, which can be an adhesive material, that extends laterally from the lateral side of the flexible circuit 722. As shown, the flexible polymer layer 725 has a wavy outer surface that provides a substantially smooth transition with the lateral sides 720A, 720B of the support member 720. This smooth transition can have mechanical, clinical, and electrical benefits. For example, the illustrated configuration eliminates relatively sharp edges on the strut that, if present, would have an adverse effect on tissue (such as myocardial tissue) contacting the strut 716A. Additionally, the polymer layer 725 can reduce or minimize edge effects at the various ablation electrodes that may otherwise be present on the flexible circuit 722. In an embodiment, the polymer layer 725 can include a flexible adhesive material that operates to attach the flexible circuit 722 to the support member 720.

[0100] Figure 7B An alternative strut 716B is shown that is similar in some respects to the strut 716A and includes a support member 720, a flexible circuit 722, and a flexible polymer layer 725 that forms a wavy outer surface that provides a non-invasive transition between the lateral ends of the flexible circuit 722 and the support member 720. As shown, in Figure 7B the embodiment, a portion of the flexible polymer layer 725 is disposed between the support member 720 and the flexible circuit 722. In this embodiment, this portion of the flexible polymer layer 725 provides a stress relief function in addition to operating to secure the flexible circuit 722 to the support member 720 to compensate for the different mechanical properties (such as bend modulus, stiffness, and the like) of the support member 720 and the flexible circuit 722.

[0101] Figure 7CAn alternative configuration of strut 716C is shown, which includes a support member 720 and a flexible circuit 722, as well as an outer member 723 having an oval shape with arcuate or semi-circular opposite ends 723A, 723B. As shown, the support member 720 is entirely disposed within the outer member 723, and the flexible circuit 722 is also disposed substantially so except for the outer surface 728, which includes various electrodes described in connection with various other embodiments above. Additionally, the interior of the outer member 723 is filled with a flexible polymer or adhesive material 725 that encapsulates the support member 720 and the portion of the flexible circuit 722 disposed within the outer member 723.

[0102] Figure 7D Another alternative configuration of strut 716D is shown, which is substantially similar to strut 716C but further includes an internal air gap 729 formed within the polymer material 725 between the support member 720 and the flexible circuit 722. In an embodiment, the air gap 729 can provide a mechanical interface between the support member 720 and the flexible circuit 722 to compensate for the different structural properties of these components. In an embodiment, the air gap 729 can be formed by placing a mandrel between the support member 720 and the flexible circuit 722, which is removed after the polymer material 725 is deposited into the outer member 723. Alternatively, the air gap 729 can be provided via an additional tubular member that remains in place after the polymer material is deposited.

[0103] It is well understood that for a method comprising one or more steps, the recited order is not a limitation of the claims unless there is an express or implicit contrary statement in the specification or the claims themselves. As is well known, the illustrated methods are only some examples of the many disclosed, and certain steps can be added or omitted without departing from the scope of the disclosure. Such steps can include incorporating devices, systems or methods or their components, as well as those that are well understood, conventional and routine in the art.

[0104] The connecting lines shown in the various figures included in this document are intended to represent exemplary functional relationships and / or physical couplings between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in an actual system. However, benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more apparent should not be construed as critical, required, or essential features or elements. Except as otherwise provided in the appended claims, the scope is accordingly not limited in any way, and in the appended claims, the recitation of an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." Also, when a phrase such as "at least one of A, B, or C" is used in a claim, it is intended to be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or any combination of elements A, B, or C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.

[0105] In the detailed description herein, references to "an embodiment," "embodiments," "exemplary embodiments," etc., indicate that the described embodiments may include a particular feature, structure, or characteristic, but each embodiment does not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Additionally, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is considered within the knowledge of those skilled in the art benefiting from the present disclosure to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described. After reading this description, it will be apparent to those skilled in the relevant art how to implement the present disclosure in alternative embodiments.

[0106] Furthermore, any element, component, or method step in the present disclosure is not intended to be dedicated to the public, regardless of whether the element, component, or method step is explicitly recited in the claims. No element of any claim herein shall be construed to fall under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase "means for." As used herein, the term "comprising," "including," or any other variation thereof, is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0107] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present disclosure. For example, while the embodiments described above refer to specific features, the scope of the present disclosure also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present disclosure is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the claims, together with all their equivalents.

Claims

1. A catheter for ablating cardiac tissue by irreversible electroporation, the catheter comprising: A tubular outer shaft having a proximal end and an opposite distal end; An electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly defining a central hub portion located distally and a plurality of struts, each strut including a distal portion extending from the central hub portion and a proximal portion attached to and constrained by the outer shaft, the electrode assembly including a flexible circuit having a flexible circuit hub and a plurality of flexible circuit branches extending proximally from the flexible circuit hub, the flexible circuit further comprising: A distal ablation electrode including an ablation electrode hub portion located on the flexible circuit hub and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a corresponding one of the flexible circuit branches and terminating at a proximal end; And A plurality of proximal ablation electrodes, each of the proximal ablation electrodes being located on a corresponding one of the flexible circuit branches and having a distal end spaced proximally from the proximal end of an adjacent radial segment of the distal ablation electrode.

2. The catheter according to claim 1, further comprising a plurality of strut sensing electrodes located on each strut.

3. The catheter according to claim 2, wherein, The most distal strut sensing electrode on each strut is disposed within the periphery of each of the radial segments of the distal ablation electrode and is electrically isolated from the distal ablation electrode.

4. The catheter according to claim 2 or 3, wherein One or more of the plurality of strut sensing electrodes are disposed within the periphery of each of the proximal ablation electrodes and are electrically isolated therefrom.

5. The catheter according to any one of claims 1-4, wherein, The proximal end of each radial segment has a semi-circular shape.

6. The catheter according to any one of claims 1-5, wherein, The distal end of each proximal ablation electrode has a semi-circular shape.

7. The catheter according to any one of claims 1-6, wherein, Each of the proximal ablation electrodes includes one or more proximal ablation electrode holes formed therein, and one of the strut sensing electrodes is disposed in a corresponding one of the proximal ablation electrode holes.

8. The catheter according to claim 7, wherein, Each proximal ablation electrode hole is bounded by the corresponding inner circumferential surface of the proximal ablation electrode, and the outer circumferential surface of each strut sensing electrode is spaced from the corresponding inner circumferential surface of the proximal ablation electrode.

9. The catheter according to any one of claims 3-8, wherein, Each of the radial segments of the distal ablation electrode includes a proximal portion in which a radial segment hole is formed, and each of the most distal strut sensing electrodes is disposed in a corresponding one of the radial segment holes.

10. The catheter according to claim 9, wherein, Each radial segment hole is bounded by the corresponding inner circumferential surface of the radial segment, and the outer circumferential surface of each most distal strut sensing electrode is spaced from the corresponding inner circumferential surface of the radial segment.

11. The catheter according to claim 9 or 10, wherein, Each of the radial segments has a distal portion opposite the proximal portion, and the proximal portion has a greater lateral width than the distal portion.

12. The catheter according to any one of claims 1-11, further comprising a hub sensing electrode centrally located on the central hub portion of the electrode assembly.

13. The catheter according to any one of claims 1 - 12, wherein, Each strut has a lateral edge, and the lateral edge has a non-invasive shape.

14. The catheter according to any one of claims 1-13 further comprises a central column, which extends distally from the distal end of the tubular shaft and extends into the internal space defined by the electrode assembly when the electrode assembly is in the expanded configuration, and the central column includes a reference electrode.

15. The catheter according to any one of claims 1-14, wherein, The electrode assembly further comprises a support member having a support member hub and a plurality of support member branches extending proximally from the support member hub, wherein the flexible circuit hub is disposed above the support member hub, and each flexible circuit branch of the flexible circuits is disposed above a corresponding one of the support member branches.

16. A catheter for ablating cardiac tissue by irreversible electroporation, the catheter comprising: A tubular outer shaft having a proximal end and an opposite distal end; An electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly defining a central hub portion at the distal side and a plurality of struts, each strut including a distal portion extending from the central hub portion and a proximal portion attached to and constrained by the outer shaft, and the electrode assembly includes: A support member having a support member hub and a plurality of support member branches extending proximally from the support member hub; A flexible circuit attached to the outer surface of the support member and having a flexible circuit hub disposed on the support member hub and a plurality of flexible circuit branches, each flexible circuit branch of the flexible circuits being disposed above a corresponding one of the support member branches, and the flexible circuit further includes: A distal ablation electrode including an ablation electrode hub portion located on the flexible circuit hub and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a corresponding one of the flexible circuit branches and terminating at the proximal end; and A plurality of proximal ablation electrodes, each of the proximal ablation electrodes being located on a corresponding one of the flexible circuit branches and having a distal end spaced proximally from the proximal end of an adjacent radial segment of the distal ablation electrode.

17. The catheter according to claim 16, wherein, The flexible circuit further includes a plurality of strut sensing electrodes located on each strut, wherein the most distal strut sensing electrode on each strut is disposed within the periphery of each of the radial segments of the distal ablation electrode and is electrically isolated from the distal ablation electrode, and wherein one or more of the plurality of strut sensing electrodes are disposed within the periphery of each of the proximal ablation electrodes and are electrically isolated therefrom.

18. The catheter according to claim 17, wherein, The proximal end of each radial segment has a semi-circular shape.

19. The catheter according to claim 18, wherein, The distal end of each proximal ablation electrode has a semi-circular shape.

20. The catheter according to claim 17, wherein, Each of the proximal ablation electrodes includes one or more proximal ablation electrode holes formed therein, and one of the strut sensing electrodes is disposed in a corresponding one of the proximal ablation electrode holes.

21. The catheter according to claim 20, wherein, Each proximal ablation electrode aperture is bounded by a respective inner peripheral surface of the proximal ablation electrode, and wherein an outer peripheral surface of each strut sensing electrode is spaced from the respective inner peripheral surface of the proximal ablation electrode.

22. The catheter according to claim 17, wherein, Each radial segment of the distal ablation electrode includes a proximal portion in which a radial segment aperture is formed, and wherein each of the most distal strut sensing electrodes is disposed within a respective one of the radial segment apertures.

23. The catheter according to claim 22, wherein, Each radial segment aperture is bounded by a respective inner peripheral surface of the radial segment, and wherein an outer peripheral surface of each of the most distal strut sensing electrodes is spaced from the respective inner peripheral surface of the radial segment.

24. The catheter according to claim 17, further comprising a hub sensing electrode centered on a central hub portion of the electrode assembly.

25. The catheter according to claim 17, further comprising a central post that extends distally from a distal end of the tubular shaft and extends into an internal space defined by the electrode assembly when the electrode assembly is in an expanded configuration, the central post including a reference electrode.

26. A catheter for ablating cardiac tissue by irreversible electroporation, the catheter comprising: A tubular outer shaft having a proximal end and an opposite distal end; An electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly defining a central hub portion located distally and a plurality of struts, each strut including a distal portion extending proximally from the central hub portion and a proximal portion attached to and constrained by the outer shaft, the electrode assembly including: A support member formed of a superelastic material and having a support member hub and a plurality of support member branches integrally formed with and extending proximally from the support member hub; A flexible circuit attached to an outer surface of the support member and having a flexible circuit hub disposed above the support member hub and a plurality of flexible circuit branches integrally formed with the flexible circuit hub, each of the flexible circuit branches being disposed above a respective one of the support member branches, the flexible circuit further including: A distal ablation electrode including an ablation electrode hub portion located on the flexible circuit hub, And a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a respective one of the flexible circuit branches; A plurality of proximal ablation electrodes, each of the proximal ablation electrodes being located on a respective one of the flexible circuit branches; A plurality of strut sensing electrodes including a plurality of distal strut sensing electrodes and one or more proximal strut sensing electrodes, each of the plurality of distal strut sensing electrodes being disposed within and electrically isolated from a respective one of the radial segments of the distal ablation electrode, and the one or more proximal strut sensing electrodes being disposed within and electrically isolated from each of the proximal ablation electrodes.

27. The catheter according to claim 26, wherein, Each of the proximal ablation electrodes has a proximal end and a distal end with a semi-circular shape, and wherein each proximal end of the radial segments has a semi-circular shape.

28. The catheter according to claim 26, wherein, Each of the proximal ablation electrodes includes one or more proximal ablation electrode holes formed therein, and wherein each proximal strut sensing electrode of the proximal strut sensing electrodes is disposed in a respective one of the proximal ablation electrode holes.

29. The catheter according to claim 28, wherein, Each proximal ablation electrode hole is bounded by the respective inner circumferential surface of the proximal ablation electrode, and wherein the outer circumferential surface of each proximal strut sensing electrode is spaced apart from the respective inner circumferential surface of the proximal ablation electrode.

30. The catheter according to claim 26, wherein, Each radial segment of the distal ablation electrode includes a proximal portion in which a radial segment hole is formed, and wherein each of the distal strut sensing electrodes is disposed in a respective one of the radial segment holes.

31. The catheter according to claim 30, wherein, Each radial segment hole is bounded by the respective inner circumferential surface of the radial segment, and wherein the outer circumferential surface of each distal strut sensing electrode is spaced apart from the respective inner circumferential surface of the radial segment.

32. A catheter for ablating cardiac tissue by irreversible electroporation, the catheter comprising: A tubular outer shaft having a proximal end and an opposite distal end; An electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly including a flexible circuit having a central flexible circuit hub located distally and a plurality of flexible circuit branches extending proximally from the hub portion, each of the flexible circuit branches at least partially defining an electrode assembly strut and including a proximal portion attached to and constrained by the outer shaft, the flexible circuit further including: A distal ablation electrode including an ablation electrode hub portion located on the flexible circuit hub and a plurality of radial segments integrally formed with the ablation electrode hub portion, each of the radial segments extending proximally along a portion of a respective one of the flexible circuit branches and terminating at a proximal end; And A plurality of proximal ablation electrodes, each of the proximal ablation electrodes being located on a respective one of the flexible circuit branches and having a distal end spaced apart from the proximal end of an adjacent radial segment of the distal ablation electrode.

33. The catheter according to claim 32, wherein, The proximal end of each radial segment has a semi-circular shape, and wherein the distal end of each proximal ablation electrode has a semi-circular shape.

34. The catheter according to claim 33, wherein, The flexible circuit further includes a plurality of strut sensing electrodes located on each strut, wherein the most distal strut sensing electrode on each strut is disposed within the periphery of each of the radial segments of the distal ablation electrode and is electrically isolated from the distal ablation electrode, and wherein one or more of the plurality of strut sensing electrodes are disposed within the periphery of each of the proximal ablation electrodes and are electrically isolated therefrom.

35. The catheter according to claim 34, wherein, The flexible circuit further includes a hub sensing electrode centrally located on the flexible circuit hub.

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