Ablation catheter with incision electrode

Abstract

A catheter for ablation of cardiac tissue by irreversible electroporation includes a tubular shaft and an electrode assembly extending distally from the tubular shaft. The electrode assembly defines a distal flexible central hub portion and a flexible spline. The distal ablation electrode includes a hub portion and an ablation electrode radial section. Each ablation electrode radial segment includes a first series of gaps and a second series of gaps. The first series of gaps are spaced apart from each other along a length of the ablation electrode radial segment and extend partially across a width of the ablation electrode radial segment from the first longitudinal side toward the second longitudinal side. The second series of gaps are spaced apart from each other along the length of the ablation electrode radial segment and extend partially across the width of the ablation electrode radial segment from the second longitudinal side toward the first longitudinal side.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 583,024, filed September 15, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to medical systems and methods for ablating tissue in a patient's body. More particularly, this disclosure relates to medical systems and methods for ablating tissue via electroporation. Background Technology

[0004] Ablation procedures are used to treat a wide range of conditions in patients. Ablation can be used to treat arrhythmias, benign tumors, malignant tumors, and to control bleeding during the procedure. Typically, ablation is performed using thermal ablation techniques, including radiofrequency (RF) ablation and cryoablation. In RF ablation, a probe is inserted into the patient's body, and radiofrequency waves are delivered through the probe to the surrounding tissue. The radiofrequency waves generate heat, which destroys the surrounding tissue and burns blood vessels. In cryoablation, a hollow needle or cryoprobe is inserted into the patient's body, and a cooled, thermally conductive fluid circulates through the probe to freeze and kill the surrounding tissue. Both RF and cryoablation techniques indiscriminately kill tissue through cell necrosis, which may damage or kill otherwise healthy tissue, such as tissue in the esophagus, phrenic nerve cells, and tissue in the coronary arteries.

[0005] Another ablation technique uses electroporation. In electroporation, or electropermeabilization, an electric field is applied to the cell to increase the permeability of the cell membrane. Depending on the strength of the electric field, electroporation can be reversible or irreversible. If electroporation is reversible, the increased permeability of the cell membrane can be used to introduce chemicals, drugs, and / or DNA into the cell before it heals and recovers. If electroporation is irreversible, the affected cells are killed through apoptosis.

[0006] Irreversible electroporation can be used as a non-thermal ablation technique. In irreversible electroporation, short bursts of high-voltage pulses are used to generate an electric field strong enough to kill cells through apoptosis. In the ablation of cardiac tissue, irreversible electroporation can be a safe and effective alternative to the indiscriminate killing of cells by thermal ablation techniques such as RF ablation and cryoablation. Irreversible electroporation can be used to kill target tissues (such as myocardial tissue) by using the intensity and duration of an electric field that kills the target tissue without permanently damaging other cells or tissues (such as non-targeted myocardial tissue, erythrocytes, vascular smooth muscle tissue, endothelial tissue, and nerve cells). There is a continuing need for improved devices and methods for performing cardiac tissue ablation via irreversible electroporation. Summary of the Invention

[0007] In Example 1, a catheter for ablation of cardiac tissue via irreversible electroporation is provided. The catheter includes a tubular outer shaft and an electrode assembly extending distally from the distal end of the tubular shaft. The electrode assembly defines a flexible central hub portion located distally and a plurality of flexible splines. Each flexible spline includes a distal portion extending proximally from the central hub portion, a proximal portion attached to and constrained by the shaft, and an intermediate portion between the proximal and distal portions. The distal ablation electrode includes an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of which extends longitudinally along at least one segment of a corresponding intermediate portion of the flexible spline to a corresponding proximal end. Each of the radial segments of the ablation electrode includes a first longitudinal side, a second longitudinal side, and a width extending between the first longitudinal side and the second longitudinal side. Each radial segment of the ablation electrode includes: a first series of gaps that are spaced apart from each other along the length of the radial segment of the ablation electrode and extend from the first longitudinal side toward the second longitudinal side partially across the width of the radial segment of the ablation electrode; and a second series of gaps that are spaced apart from each other along the length of the radial segment of the ablation electrode and extend from the second longitudinal side toward the first longitudinal side partially across the width of the radial segment of the ablation electrode.

[0008] In Example 2, according to the catheter of Example 1, the electrode assembly includes a flexible circuit having a flexible circuit hub and a plurality of flexible circuit branches integrally formed with the flexible circuit hub and extending proximally from the flexible circuit hub.

[0009] In Example 3, the conduit according to Example 2 is provided, wherein the electrode assembly includes a shape memory support member coupled to a flexible circuit.

[0010] In Example 4, the catheter according to Example 3 is provided, wherein the shape memory support member faces inward and is opposite to the ablation electrode on the electrode assembly.

[0011] In Example 5, the conduit according to any one of Examples 3 and 4, wherein the support structure is formed of a nickel-titanium alloy.

[0012] In Example 6, the catheter according to any one of Examples 1 to 5, wherein the first series gaps and the second series gaps are formed by mechanical cutting.

[0013] In Example 7, the catheter according to any one of Examples 1 to 5, wherein the first series gaps and the second series gaps are formed by laser cutting.

[0014] In Example 8, the conduit according to any one of Examples 1 to 7, wherein the first series gaps and the second series gaps are filled with a coating.

[0015] In Example 9, the conduit according to Example 8 is provided, wherein the coating comprises parylene.

[0016] In Example 10, the catheter according to any one of Examples 1 to 9 is wherein the distal ablation electrode is formed of copper.

[0017] In Example 11, the conduit according to any one of Examples 1 to 10, wherein the flexible circuit further includes a hub sensing electrode centrally located on the hub of the flexible circuit.

[0018] In Example 12, the catheter according to any one of Examples 1 to 11 further includes one or more axial electrodes located proximal to the distal end of the tubular outer axis.

[0019] In Example 13, according to the catheter of Example 12, the distal ablation electrode and one or more axial electrodes are configured to define an anode / cathode electrode pair for the delivery of electroporation ablation energy to the target tissue.

[0020] In Example 14, the catheter according to any one of Examples 1 to 13, wherein the electrode assembly further includes 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 is disposed above a corresponding one of the support member branches.

[0021] In Example 15, the catheter according to Example 14, wherein the electrode assembly includes a first region comprising an adhesive layer disposed between the flexible circuit and the support member and mechanically attaching the flexible circuit to the support member; and a second region in which the flexible circuit and the support member are not directly mechanically attached together.

[0022] In Example 16, a catheter for ablation of cardiac tissue via irreversible electroporation includes: a tubular shaft having a distal end; an electrode assembly extending distally from the distal end of the tubular shaft, the electrode assembly defining a flexible central hub portion located distally and a plurality of flexible splines, each flexible spline including a distal portion extending proximally from the central hub portion, a proximal portion attached to and constrained by the shaft, and an intermediate portion between the proximal and distal portions; a distal ablation electrode including an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of the plurality of radial segments extending along the central hub portion. At least one segment of the corresponding middle portion of the flexible spline extends longitudinally to the corresponding proximal end; wherein each of the radial segments of the ablation electrode includes a first longitudinal side, a second longitudinal side, and a width extending between the first longitudinal side and the second longitudinal side, each radial segment of the ablation electrode including: a first series of gaps spaced apart from each other along the length of the radial segment of the ablation electrode and extending partially across the width of the radial segment of the ablation electrode from the first longitudinal side toward the second longitudinal side; and a second series of gaps spaced apart from each other along the length of the radial segment of the ablation electrode and extending partially across the width of the radial segment of the ablation electrode from the second longitudinal side toward the first longitudinal side.

[0023] In Example 17, the catheter according to Example 16 is provided, wherein the electrode assembly includes a flexible circuit having a flexible circuit hub and a plurality of flexible circuit branches integrally formed with and extending proximally from the flexible circuit hub.

[0024] In Example 18, the conduit according to Example 17 is provided, wherein the electrode assembly includes a shape memory support member coupled to a flexible circuit.

[0025] In Example 19, according to the catheter described in Example 18, the shape memory support member faces inward and is opposite to the ablation electrode on the electrode assembly.

[0026] In Example 20, the conduit is according to Example 18, wherein the support structure is formed of a nickel-titanium alloy.

[0027] In Example 21, the catheter according to Example 16 is provided, wherein the first series of gaps and the second series of gaps are formed by mechanical cutting.

[0028] In Example 22, the catheter according to Example 16 is provided, wherein the first series of gaps and the second series of gaps are formed by laser cutting.

[0029] In Example 23, the conduit according to Example 16 is provided, wherein the first series gaps and the second series gaps are filled with a coating.

[0030] In Example 24, the conduit is according to Example 23, wherein the coating is parylene.

[0031] In Example 25, the catheter according to Example 16 is provided, wherein the distal ablation electrode is formed of copper.

[0032] In Example 26, the conduit according to Example 16 is further provided, wherein the flexible circuit also includes a hub sensing electrode centrally located on the hub of the flexible circuit.

[0033] In Example 27, the catheter according to Example 16 further includes one or more axial electrodes located proximal to the distal end of the tubular outer axis.

[0034] In Example 28, according to the catheter of Example 27, the distal ablation electrode and one or more axial electrodes are configured to define an anode / cathode electrode pair for the delivery of electroporation ablation energy to the target tissue.

[0035] In Example 29, the catheter according to Example 16, wherein the electrode assembly further includes 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 is disposed above a corresponding one of the support member branches.

[0036] In Example 30, a catheter for irreversibly ablating cardiac tissue via electroporation is provided, the catheter comprising: a tubular outer shaft having a proximal end and an opposing distal end; an electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly defining a distally located central hub portion and a plurality of splines, each spline including a distal portion extending proximally from the central hub portion, a proximal portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal and distal portions; the electrode assembly comprising: a support member formed of a hyperelastic 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; and a flexible circuit, the flexible circuit being configured... The flexible circuit is disposed above the outer surface of the support member and has a flexible circuit hub disposed above the hub of the support member and a plurality of flexible circuit branches integrally formed with the flexible circuit hub. Each of the flexible circuit branches is disposed above a corresponding branch of the support member. The flexible circuit also includes: an outwardly oriented distal ablation electrode, which includes an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments. Each of the plurality of radial segments extends longitudinally along at least one segment of a corresponding intermediate portion of the flexible spline to a corresponding proximal end. Each of the ablation electrode radial segments includes a longitudinally extending serpentine conductive path through a plurality of laterally extending gaps from the ablation electrode hub portion to the proximal end.

[0037] In Example 31, the conduit according to Example 30 is provided, wherein the laterally extending gap is formed by mechanical cutting.

[0038] In Example 32, the conduit according to Example 30 is provided, wherein the laterally extending gap is filled with a coating.

[0039] In Example 33, the catheter according to Example 30 is provided, wherein the distal ablation electrode is formed of copper.

[0040] In Example 34, a catheter for ablation of cardiac tissue via irreversible electroporation includes: a tubular outer shaft having a proximal end and an opposing distal end; and an electrode assembly extending distally from the distal end of the tubular shaft, the electrode assembly defining a flexible central hub portion located distally and a plurality of flexible splines, each flexible spline including an intermediate portion; the electrode assembly includes: an outwardly oriented distal ablation electrode including an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of the plurality of radial segments extending longitudinally along at least one segment of a corresponding intermediate portion of the flexible spline to a corresponding proximal end; wherein each of the ablation electrode radial segments includes a longitudinally extending conductive path from the ablation electrode hub portion to the proximal end through a plurality of laterally extending gaps extending only partially across the radial segment.

[0041] In Example 35, the conduit according to Example 34 is provided, wherein the laterally extending gap is filled with a coating.

[0042] While several embodiments have been disclosed, other embodiments of this disclosure will become apparent to those skilled in the art from the following detailed description, which illustrates and describes illustrative embodiments of this disclosure. Therefore, the drawings and detailed description should be considered illustrative in nature and not restrictive. Attached Figure Description

[0043] Figure 1 This is a schematic diagram illustrating an exemplary clinical setting for treating a patient and the patient's heart using an electrophysiological system, according to an embodiment of the subject matter of this disclosure.

[0044] Figure 2A This is an embodiment of the subject matter of this disclosure for use in Figure 1 A perspective view of the distal portion of a splined catheter used in an electrophysiological system.

[0045] Figure 2B and Figure 2C This is an illustration in two dimensions of an embodiment of the subject matter of this disclosure. Figure 2A Partial plan view of the electrode assembly of the spline-type conduit.

[0046] Figure 2D yes Figure 2A A partial plan view of the features of the electrode assembly of the spline-type conduit.

[0047] Figure 3 and Figure 4 This is an embodiment of the subject matter of this disclosure for use in Figure 1 A plan view of the alternative electrode assembly in the catheter.

[0048] Figure 5 This is a schematic diagram showing the distal portion of a splined conduit constructed according to an embodiment of the subject matter of this disclosure in a collapsed configuration.

[0049] While this disclosure is applicable to various modifications and alternatives, specific embodiments have been shown by way of example in the accompanying drawings and described in detail below. However, it is not intended to limit the invention to the specific embodiments described. Rather, the invention is intended to cover all modifications, equivalents, and alternatives that fall within the scope of the invention as defined by the appended claims. Detailed Implementation

[0050] For the purpose of facilitating an understanding of the principles of this disclosure, reference is now made to the examples shown in the accompanying drawings, which are described below. The illustrative examples disclosed herein are not intended to be exhaustive or to limit this disclosure to the precise forms disclosed in the following detailed description. Rather, these exemplary embodiments are selected and described so that others skilled in the art can apply their teachings. Using multiple (e.g., all) features from a given example in all examples does not exceed the scope of this disclosure. Therefore, no single figure should be construed as having any dependency or requirement associated with any individual component or combination of components shown therein. Furthermore, the various components depicted in a given figure may be integrated in the example with various components in other components (and / or components not shown) depicted therein, all of which are considered to be within the scope of this disclosure.

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

[0052] Throughout this disclosure and in the claims, numerical terms (such as first and second) are used to refer to various components or features. Such use is not intended to indicate an order of components or features. Rather, numerical terms are used to assist the reader in identifying the components or features referred to and should not be interpreted narrowly as providing a specific order of components or features.

[0053] Figure 1This is a schematic diagram illustrating an exemplary clinical environment 10 for treating a patient 20 and the heart 30 of the patient 20 using an electrophysiological system 50, according to embodiments of the subject matter of this disclosure. The electrophysiological system 50 includes an electroporation catheter system 60 and an electroanatomical mapping (EAM) system 70, which includes a localization field generator 80, a mapping and navigation controller 90, and a display 92. Additionally, the clinical environment 10 includes auxiliary equipment such as an imaging device 94 (represented by a C-arm), and various controller elements configured to allow an operator to control various aspects of the electrophysiological system 50, such as a foot pedal controller 96. As those skilled in the art will understand, the clinical environment 10 may have… Figure 1 Other components not shown, and their arrangement.

[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. Furthermore, the electroporation catheter system 60 includes various connecting elements (e.g., cables, umbilical cords, and the like) that operate to functionally connect the components of the electroporation catheter system 60 to each other and to components of the EAM system 70. This arrangement of connecting elements is not essential to this disclosure, and those skilled in the art will recognize that the various components described herein can be interconnected in a variety of ways.

[0055] In one embodiment, the introducer sheath 110 is operable to provide a delivery conduit through which the electroporation catheter 100 (partially its distal portion 105) can be deployed to a specific target site within the patient's heart 30. Access to the patient's heart can be obtained via a blood vessel, such as a peripheral artery or vein. Once access to that vessel is obtained, the electroporation catheter 105 can be navigated into the patient's heart, such as into a ventricle.

[0056] In one embodiment, the electroporation catheter system 60 is configured to deliver electric field energy to a target tissue in the patient's heart 30 to induce tissue cell apoptosis, thereby preventing the tissue from conducting electrical signals.

[0057] The electroporation console 130 is configured to control functional aspects of the electroporation catheter system 60. In embodiments, the electroporation console 130 includes one or more controllers, microprocessors, and / or computers that execute code from memory to control or perform functional aspects of the electroporation catheter system 60. In embodiments, the memory may be part of one or more controllers, microprocessors, or computers, and / or part of a memory capacity accessible via a network (such as the World Wide Web). In embodiments, the electroporation console 130 includes pulse generator hardware, software, and / or firmware configured to generate electrical pulses of predetermined waveforms that are delivered to electrodes on the electroporation catheter 100 to generate an electric field sufficient to achieve the desired clinical effect, particularly ablation of target tissue via irreversible electroporation. In embodiments, the electroporation console 130 may deliver pulse waveforms to the electroporation catheter 100 in unipolar or bipolar operation.

[0058] EAM system 70 is operable to track the location of various functional components of electroporation catheter system 60 and generate high-fidelity three-dimensional anatomical and electroanatomical mappings of the cardiac chambers of interest. In an embodiment, EAM system 70 may be a RHYTHMIA™ HDx mapping system sold by Boston Scientific Corporation. Additionally, in an embodiment, mapping and navigation controller 90 of EAM system 70 includes one or more controllers, microprocessors, and / or computers that execute code from memory to control and / or perform functional aspects of EAM system 70, wherein the memory may 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 those skilled in the art will understand, Figure 1 The depiction of the electrophysiological system 50 is intended to provide a general overview of the various components of the system 50 and is in no way intended to imply that this disclosure is limited to any set of components or arrangement of components. For example, those skilled in the art will readily recognize that additional hardware components (such as junction boxes, workstations, and the like) may and are likely to be included in the electrophysiological system 50.

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

[0061] In other embodiments, impedance tracking methods can be used to track the position of various devices. In such embodiments, the positioning field is an electric field generated, for example, by an external field generator (e.g., surface electrodes), an in vivo or intracardiac device (e.g., an intracardiac catheter), or both. In these embodiments, position sensing elements can form electrodes on the tracked devices, which generate outputs received and processed by the mapping and navigation controller 90 to track the position of various position sensing electrodes within the positioning volume.

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

[0063] Regardless of the tracking method used, the EAM system 70 utilizes location information for various tracked devices, along with cardiac electrical activity acquired by, for example, an electroporation catheter 100 or another catheter or probe equipped with sensing electrodes, to generate and display via a display 92 a detailed three-dimensional geometric anatomical mapping or representation of the cardiac chambers, and an electroanatomical mapping in which the cardiac electrical activity of interest is superimposed on the geometric anatomical mapping. Furthermore, the EAM system 70 can generate graphical representations of various tracked devices within the geometric anatomical mapping and / or the electroanatomical mapping.

[0064] Embodiments of this disclosure provide systems, apparatus, and methods for the selective and rapid application of pulsed electric fields to ablate tissue via irreversible electroporation. Generally, the systems, apparatus, and methods described herein can be used to generate large electric field amplitudes in desired regions of interest and reduce peak electric field values ​​elsewhere to minimize unwanted tissue damage and arcing. Irreversible electroporation systems as described herein may 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 set in a pulmonary vein opening or sinus). The pulse waveforms disclosed herein can aid in the therapeutic treatment of various cardiac arrhythmias, such as atrial fibrillation. To deliver the pulse waveforms generated by the signal generator, one or more electrodes of the ablation device may have insulated leads configured to withstand voltage potentials in the range of hundreds to thousands of volts. The electrodes may be independently addressable, such that each electrode can be controlled (e.g., delivered energy) independently of any other electrode in the device. In this way, the electrodes can collaboratively deliver different energy waveforms using different timing sequences for electroporation of tissue.

[0065] The pulse waveforms for electroporation energy delivery 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 producing more effective ablation of lesions with reduced total energy delivered. In some embodiments, the voltage pulse waveforms disclosed herein may be hierarchical and have a nested structure. For example, the pulse waveforms may include hierarchical groupings of pulses with associated time scales. In some embodiments, the methods, systems, and apparatuses disclosed herein may include one or more of the methods, systems, and apparatuses described in International Application Serial No. PCT / US2016 / 057664, filed October 19, 2016, entitled “SYSTEMS, APPARATUSES AND METHODS FOR DELIVERY OF ABLATIVE ENERGYTO TISSUE,” the contents of which are incorporated herein by reference in their entirety.

[0066] Figure 2A This is a partial perspective view of an electroporation catheter 200 having a distal portion 205 according to an embodiment of the present disclosure. The electroporation catheter 200 and related... Figure 1Corresponding to the described electroporation catheter 100. The electroporation catheter 200 has a tubular outer shaft 208 having a distal end 209 and an electrode assembly 210 extending distally from the distal end 209 of the outer shaft 208. In embodiments, the electrode assembly 210 is configured to unfold from a collapsed configuration when confined within a delivery sheath to a predefined unfolded configuration defining an internal space 212. In some embodiments, the electrode assembly includes a plurality of ablation electrodes configured to extend from the electroporation console 130 (… Figure 1 The electrode assembly 210 receives pulsed electrical signals / waveforms, thereby generating a pulsed electric field sufficient to ablate the target tissue via irreversible electroporation. Furthermore, the electrode assembly 210 includes multiple mapping and sensing electrodes configured to, among other things, sense cardiac electrical signals and to position the electrode assembly 210 within the patient's anatomy (e.g., via...). Figure 1 The EAM system 70) and the determination of the proximity of target tissues within the anatomical structure.

[0067] In embodiments, electrode assembly 210 is primarily designed for the generation of relatively localized ablation lesions (i.e., focal lesions) compared to the relatively large-diameter circumferential lesions produced during pulmonary vein isolation surgery. However, the teachings of this disclosure can be readily adapted to catheters capable of achieving large-diameter circumferential lesions. The various electrode assembly embodiments described herein are designed to provide clinicians with extensive capabilities for monopolar and bipolar focal pulsed-field ablation of cardiac tissue, combined with the ability to perform localized (i.e., at the location of pulsed-field ablation energy delivery), high-fidelity sensing of cardiac tissue, for example, for lesion or conduction block assessment, tissue contact determination, and similar applications.

[0068] As discussed below, electrode assembly 210 defines a flexible central hub portion 214 located distally and a plurality of flexible splines 216A-216F, each flexible spline 216A-216F including a distal portion 217A-217F extending proximally from the central hub portion 214, a proximal portion 218A-218F attached to and constrained by the shaft 208, and an intermediate portion 219A-219F between the proximal portion 218A-218F and the distal portion 217A-217F. The electrode assembly includes an outwardly oriented distal ablation electrode 238, which includes an ablation electrode hub portion 240 located on a flexible central hub portion 214 and a plurality of ablation electrode radial segments 242A-242F, each of which extends longitudinally along at least one segment of a corresponding intermediate portion 219A-219F of a flexible spline 216A-216F to a corresponding proximal end 268A-268F.

[0069] During operation, the portion of splines 216A-216F near the central hub portion 214 flexes and is subjected to stress within the delivery sheath (see, for example, see...). Figure 5 The conductive material used to construct the distal ablation electrode 240 can undergo plastic deformation in the collapsed configuration. In some scenarios, the device can be retracted into a sheath and then released again. The distal ablation electrode 240 can undergo further plastic deformation during each such sheathing process. Over time, this process may affect the shape of the electrode assembly in the deployed configuration. To mitigate this effect and reduce the likelihood of plastic deformation, each of the radial segments 242A-242F of the ablation electrode includes a series of laterally extending gaps. As further described below, these gaps can form a meandering or serpentine configuration, or they can be formed by an alternating series of gaps extending laterally inward from opposite lateral edges of the radial segments.

[0070] Figures 2B-2C This is a partial plan view of the electrode assembly 210 of the electroporation conduit 200, shown in two-dimensional form to illustrate the layout of the electrode assembly 210. (See also: Common Reference) Figures 2A-2C In the illustrated embodiment, the electrode assembly 210 as a whole has a central hub portion 214 located distally and a plurality of splines 216A-216F extending proximally from the central hub portion 214. As further shown, each corresponding spline 216A-216F has a distal portion 217A-217F, a proximal portion 218A-218F, and an intermediate portion 219A-219F extending between the distal portions 217A-217F and the proximal portions 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 spline 216A-216F has a lateral width greater than the lateral width of each of the corresponding proximal portions 218A-218F and the distal portions 217A-217F. In the embodiments, the specific geometry of splines 216A-216F and related components (e.g., ablation and mapping electrodes) is optimized to provide the desired mechanical and therapeutic / diagnostic capabilities. In the described and illustrated embodiments, each of the electrode assemblies has six splines. This is for illustrative purposes, and for a given clinical application, more or fewer than six splines may be included.

[0071] In the illustrated embodiments, splines 216A-216F consist of a support member 220 and a flexible circuit 222, which is fixed to and disposed above the outer surface of the support member 220. Among other things, the support member 220 serves as the primary structural support for the electrode assembly 210 and thus primarily defines the mechanical properties of the electrode assembly 210. In some embodiments, the support member 220 is formed of a hyperelastic material (metal or polymer) to provide the electrode assembly 210 with the desired mechanical / structural properties. In some embodiments, the support member 220 is formed of a hyperelastic metallic alloy, such as a nickel-titanium alloy.

[0072] Support member 220 includes support member hub 224 and multiple support member branches 226A-226F. In an embodiment, support member branches 226A-226F are integrally formed with and extend proximally from support member hub 224. For example, the entire support member 200 can be cut from a single sheet of material using conventional manufacturing techniques. This single structure provides robust structural properties, such as selective flexibility and enhanced fatigue characteristics, particularly in areas subjected to relatively high stresses during the manufacture and use of the electroporation conduit 200. Forming support member 220 from a hyperelastic material, such as a nickel-titanium alloy, facilitates the configuration of support member 220 to exhibit its desired unconstrained shape due to the shape memory properties of the material, such as... Figure 2A As shown, this also provides sufficient flexibility to collapse the electrode assembly 210 within the delivery sheath. In an embodiment, the support member branches 226A-226F can be selectively configured along their length to adjust the mechanical properties of the electrode assembly 210.

[0073] 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 an inwardly facing 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 inwardly facing support member branches 226A-226F. The flexible circuit 222 includes a layered structure comprising one or more dielectric substrate layers and conductive traces formed thereon. In some embodiments, the flexible circuit branches 234A-234F include a layered structure, which is a typical structure for flexible circuits used in electrode assemblies of medical devices. For example, flexible circuit branches 234A-234F include a dielectric base layer disposed above support member branches 226A-226F, an optional internal flexible adhesive layer above the base layer, a conductive trace layer above the adhesive layer (if present), and a dielectric upper layer above the conductive trace layer. The dielectric material chosen for these layers can be any conventional material suitable for flexible circuits in medical devices, such as polyamide. Similar to support member 220, the single construction of flexible circuit 222 enhances its structural properties, for example, by minimizing joints or other discontinuities at areas subjected to relatively high stress during use.

[0074] As shown in the figure, 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. Furthermore, 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 branch of the flexible circuit 234A-234F. The flexible circuit 222 also includes a plurality of proximal ablation electrodes 244A-244F. As shown in the figure, each of the proximal ablation electrodes 244A-244F is located on a corresponding branch of the flexible circuit 234A-234F. In the embodiment, the distal ablation electrode 238 is positioned opposite to the support member 220 on the flexible circuit 222, and the distal ablation electrode 238 is outwardly oriented.

[0075] As further shown, the flexible circuit 222 includes a plurality of spline sensing electrodes 250. In the illustrated embodiment, each of the spline sensing electrodes 250 is disposed within the perimeter 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 distal spline sensing electrodes 250 is disposed within the perimeter 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. Furthermore, a plurality of more proximal spline sensing electrodes 250 are disposed along a corresponding one of each of the proximal ablation electrodes 244A-244F and are disposed within their perimeters and are electrically isolated from them.

[0076] In some embodiments, the structural functionality of the support member 220 can be provided by a suitably designed flexible circuit 222. Therefore, although the electrode assembly 210 is described in detail as including the support member 220 as a primary structural member, in other embodiments, the support member 220 can be entirely omitted, and the corresponding functionality can be provided by the flexible circuit 222.

[0077] In a particular illustrated embodiment, the electroporation conduit 200 includes a central post 258 extending distally from the distal end 209 of the outer shaft 202. As shown, the central post 258 extends partially into the internal space 212 and includes post electrodes 260. As further shown in the illustrative embodiment, an optional irrigation lumen 261 is supported by the central post 258. In embodiments, the central post 258 may accommodate additional components. For example, in one embodiment, a magnetic navigation sensor (not shown) may be partially or entirely disposed within the central post 258. However, in other embodiments, such sensors may be located elsewhere on the electroporation conduit 200 (e.g., within the outer shaft 202). In the illustrated embodiment, the electrode assembly 210 also includes a hub sensing electrode 264 centrally located on the flexible circuit hub 230.

[0078] The column electrode 260 can provide numerous functional advantages. In one example, the column electrode 260 can operate as a reference for a monopolar electrogram, replacing reliance on surface ECG patch electrodes as otherwise known in the art. The position of the column electrode 260 for this purpose brings the reference electrode closer to the sensed tissue than might be achievable using conventional surface ECG methods, which advantageously minimizes far-field noise and provides a sharper monopolar electrogram than might be achievable using surface ECG electrodes. The column electrode 260 can also be operated to sense and measure other electrical parameters, such as the voltage between it and the ablation electrode or other sensing electrode on the electrode assembly 210, thereby providing data that, in some examples, can be used to determine the shape of the electrode assembly during use (including when deformed by forces exerted by the heart wall), and via the EAM system 70 ( Figure 1 Displays shape information.

[0079] In one 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 position the spline sensing electrode 250 against or close to the tissue to be mapped. In the illustrated embodiment, the inclusion of the hub sensing electrode 264 further enhances bipolar sensing capability by providing six additional bipolar poles when paired with any of the distal spline sensing electrodes 250. In some embodiments, the hub sensing electrode 264 may be omitted entirely and replaced by a distal ablation electrode that does not have an aperture centrally located on the flexible circuit hub 238.

[0080] In various embodiments, each of the corresponding proximal ablation electrodes 244A-244F, distal ablation electrode 238, spline sensing electrode 250, and hub sensing electrode 264 is electrically connected to the electroporation console 130, respectively. Figure 1The control system is individually addressable to provide a wide range of ablation and sensing modes, such as unipolar and bipolar modes. During unipolar ablation, a single ablation electrode, a group of ablation electrodes, or all ablation electrodes commonly on electrode assembly 210 are commonly electrically coupled and configured to operate in one polarity, while electrodes located elsewhere (e.g., diffusion electrodes located on the patient, typically in the back, hip, or other suitable anatomical location, or electrodes on different catheters or probes outside the cardiac chamber where electrode assembly 210 is located) are configured to operate in the opposite polarity. In one example, the distal ablation electrode 238 and all proximal ablation electrodes 244A-244F are configured to be commonly electrically coupled as either an anode or a cathode, and the extracorporeal diffusion electrode on the back patch is configured as either a cathode or an anode. In other examples, the selected proximal ablation electrode and optionally the distal ablation electrode 238 may be configured to operate together as either an anode or a cathode, and the extracorporeal diffusion electrode is configured as either a cathode or an anode. The foregoing example advantageously allows for the selective guidance of the generated electric field to optimize electroporation effectiveness based on the relative orientation of the ablation component 210 to the target tissue. A wide range of monopolar ablation electrode configurations can be utilized.

[0081] During a bipolar ablation operation, a first set of one or more ablation electrodes of electrode assembly 210 is configured as an anode (or cathode), and a second set of one or more other ablation electrodes of electrode assembly 210 is configured as a cathode (or anode). In the example, the bipolar ablation electrode assembly may include electrodes on different splines, or may be formed between one or more proximal ablation electrodes and distal ablation electrodes.

[0082] Similarly, any one of the spline sensing electrode 250, the pillar reference electrode 260, or the hub sensing electrode 264 can also be individually addressed for any number of combinations of bipolar sensing and mapping. Furthermore, in embodiments, individual addressability allows the control system to configure any one of the spline sensing electrode and / or the hub sensing electrode 264 as an ablation electrode, thereby cooperating in unipolar or bipolar modes with any of the distal ablation electrode 238 and the proximal ablation electrodes 244A-244F.

[0083] Special Reference Figure 2CEach 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 longitudinally from the distal ablation electrode hub portion 240. As further shown, a radial segment opening 272 is formed in each of the proximal portions 266A-266F, and a corresponding one of the distal spline sensing electrodes 250 is disposed within each of the radial segment openings 272. In the illustrated embodiment, each of the proximal portions 266A-266F has a larger lateral width than the corresponding distal portion 270A-270F to at least partially accommodate the distal spline sensing electrode 250. In one example, the central hub portion 214 includes the following structures and thicknesses: a support member 220 (with a thickness of approximately 76 micrometers), a flexible circuit 222 (also with a thickness of approximately 76 micrometers), and a distal ablation electrode 240 (with a thickness of approximately 8 micrometers).

[0084] In the collapsed configuration, splines 216A-216F are flattened relative to their bulbous or generally spherical shape in the unfolded configuration, and the electrode assembly is configured to fit within a delivery sheath. The portion of splines 216A-216F closest to the central hub portion 214 abruptly flexes and is subjected to stress within the delivery sheath. For example, the central hub portion 214 may extend nearly orthogonally to splines 216A-216F and provide the greatest amount of deformation stress to splines 216A-216F just close to the central hub portion 214. While the support member 220 and the flexible circuitry are constructed of materials configured to withstand stress and recover from deformation as the electrode assembly 210 transitions between the collapsed and unfolded configurations, the conductive material used to construct the distal ablation electrode 240 is generally not flexible and does not respond to plastic deformation in the collapsed configuration. After only a few transitions between the collapsed and unfolded configurations, the electrode assembly 210 can undergo significant flattening from the intended bulb profile to its shape in the unfolded configuration.

[0085] Additional special reference Figure 2CEach of the radial segments 242A-242F of the distal ablation electrode 238 includes a longitudinally extending serpentine conductive path 280A-280F from the distal ablation electrode hub portion 240 to the proximal end 268A-268F, formed by a plurality of spaced laterally extending gaps 282A-282F on the radial segments 242A-242F, wherein each of the laterally extending gaps 282A-282F extends only partially across the radial segments 242A-242F. For example, the laterally extending gaps among the plurality of laterally extending gaps 282A-282F on the radial segments may be generated from one side, the other side, or both sides of the radial segments 242A-242F, leaving conductive workpieces therebetween, such that no laterally extending gap extends all the way to the bottom across the radial segments 242A-242F of the distal ablation electrode 238. In some embodiments, the gap can be formed by: a mechanical cutting process that cuts laterally extending gaps in the formed radial segments; a laser cutting process that can remove more material from the formed radial segments in each laterally extending gap; or forming or casting the distal ablation electrode from a conductive material to initially include the gap. In some examples, gaps 282A-282F are filled, for example, using a parylene coating. In some embodiments, gaps 282A-282F extend completely through the depth of the distal ablation electrode 238 but do not extend into the flexible circuitry 222 below the distal ablation electrode 238. In embodiments, gaps 282A-282F are formed in the high-stress region of the distal ablation electrode 238 when subjected to a collapse configuration, and this high-stress region can extend across the radial segments 242A-242F to the distal ablation hub portion 240, and therefore gaps 282A-282F can also be included in or extend into the distal ablation hub portion 240.

[0086] Figure 2DA portion of a distal ablation electrode 238 is shown, which includes a radial segment (such as radial segment 242A) in the region between a proximal end 268A and a distal ablation hub portion 240. In the illustrated embodiment, the distal ablation electrode 238 is formed of a conductive pad (such as a copper pad) disposed on and electrically coupled to the flexible circuit 222. The distal ablation electrode 238 includes an uninterrupted longitudinally extending conductive path 280A extending from the distal ablation electrode 238 to the proximal end 268A through the radial segment 242A. Each of the radial segments 242A-242F, as shown with respect to the radial segment 242A, includes a first longitudinal side 290A1 and a second longitudinal side 290A2, and a plurality of laterally extending gaps 282A spaced apart along the longitudinal side 290A to form the conductive path 280A. In the illustrated embodiment, more than one gap can be formed at the same latitude, such as the gap from the second longitudinal side 290A2 being at the same latitude as the gap from the first longitudinal side 290A1, so as to leave a portion 291A of conductive path 280A between the gaps (or between the gap and the longitudinal side). Although Figure 2D The connecting portion 291A is shown extending inward from the lateral edge of the radial segment, but in other embodiments, the connecting portion 291A is positioned adjacent to the longitudinal side.

[0087] In one embodiment, each of the ablation electrode radial segments 242A-242F (such as radial segment 242A) includes a first longitudinal side 290A1, a second longitudinal side 290A2, and a width (W) extending between the first longitudinal side 290A1 and the second longitudinal side 290A2. Each ablation electrode radial segment (such as radial segment 242A) includes a first series of gaps 292A1 and a second series of gaps 292A2. The first series of gaps 292A1 includes gaps 282A that are spaced apart from each other along the length (L) of the ablation electrode radial segment 242A and extend partially across the width W of the ablation electrode radial segment 242A from the first longitudinal side 290A1 to the second longitudinal side 290A2. The second series of gaps 292A2 includes gaps 282A that are spaced apart from each other along the length (L) of the radial segment 242A of the ablation electrode and extend partially across the width W of the radial segment 242A from the second longitudinal side 290A1 to the first longitudinal side 290A1. In one embodiment, the gaps in the first series of gaps 292A1 and the gaps in the second series of gaps 292A2 may share the same latitude. In another embodiment, the gaps in the first series of gaps 292A1 are inserted between the gaps in the second series of gaps 292A2. In each embodiment, a serpentine conductive path 280A is formed between the gaps 282A along the length L of the radial segment 242A of the ablation electrode.

[0088] The characteristics of the laterally extending gaps 282A-282F can be modified to adjust and influence the overall effect of the plastic deformation of the radial segments 242A-242F of the electrodes on the shape of the electrode assembly. According to various embodiments, the laterally extending gaps 282A-282F may be provided substantially along the entire distal portion 270 of the radial segments 242A-242F. In other embodiments, the gaps 282A-282F extend substantially along the entire length of the radial segments 242A-242F. In some embodiments, the gaps 282A-282F are configured to remove approximately 30% to 60% of the copper in the corresponding region of the radial segment of the electrode. In various embodiments, the laterally extending gaps 282A-282F have a width between approximately 20% and 50% of the width of the electrode material between the gaps. In some embodiments, the gaps 282A-282F extend laterally from approximately 50% to 90% of the distance across the radial segments.

[0089] Figures 3-4 This is an embodiment of the subject matter of this disclosure for use in Figure 1 A diagram illustrating the layout of alternative electrode assemblies (such as alternative distal ablation electrodes) in a catheter. Figure 3 A portion of electrode assembly 310 is shown, which is substantially similar to electrode assembly 210 and includes a central hub portion 314, a plurality of splines 316A-316F, and flexible circuitry 322. Figure 3 The embodiment differs from electrode assembly 210 in that the proximal end 368 of each radial segment 342A-342F of the distal ablation electrode is substantially linear (i.e., not semi-circular), and the distal end 376 of each proximal ablation electrode 344A-344F is also substantially linear, such that the opposing surfaces of the proximal ends 368 of each radial segment 342A-342F are substantially parallel to the opposing surfaces of the opposing distal ends of the corresponding proximal ablation electrodes 344A-344F. Each of the radial segments 242A-242F of the distal ablation electrode 238 includes a longitudinally extending serpentine conductive path 380A-380F from the distal ablation electrode hub portion 340 to the proximal end 368A-368F, the serpentine conductive path 380A-380F being formed between a plurality of spaced laterally extending gaps 382A-382F on the radial segments 342A-342F, wherein each of the laterally extending gaps 382A-382F extends only partially across the radial segments 342A-342F.

[0090] Figure 4 A portion of electrode assembly 410 is shown, which includes a central hub portion 414, a plurality of splines 416A-416F, and flexible circuitry 422. As will be understood, electrode assembly 410 also includes a support member (not shown) having a configuration substantially the same as that of support member 220 of electrode assembly 210. Figure 4 The embodiment differs from electrode assembly 210 in that the proximal end 468 of each radial segment 442A-442F of the distal ablation electrode terminates distal to and spaced apart from the distal spline sensing electrode 450 on each spline. Each of the radial segments 442A-442F of the distal ablation electrode 438 includes a longitudinally extending serpentine conductive path 480A-480F from the distal ablation electrode hub portion 440 to the proximal ends 468A-468F, the serpentine conductive path 480A-480F being formed between a plurality of spaced laterally extending gaps 482A-482F on the radial segments 442A-442F, wherein each of the laterally extending gaps 482A-482F extends only partially across the radial segments 442A-442F.

[0091] Figure 5 A portion of electrode assembly 510 in a collapsed configuration is shown. Electrode assembly 510 includes a central hub portion 514, a plurality of splines 516A-516F, and flexible circuitry 522. As will be understood, electrode assembly 510 also includes a support member (not shown) having a configuration substantially the same as that of support member 220 of electrode assembly 210. The portions of splines 516A-516F near the central hub portion 514 are abruptly flexed and stressed within the delivery sheath. For example, the central hub portion 514 may extend approximately orthogonally to splines 516A-516F and provide the greatest amount of deformation stress to splines 516A-516F just near the central hub portion 514. The proximal end 568 of each distal ablation electrode radial segment 542A-542F terminates at the distal end of the distal spline sensing electrode on each spline and is spaced apart from the distal spline sensing electrode. Each of the radial segments 542A-542F of the distal ablation electrode 538 includes a longitudinally extending serpentine conductive path 580A-580F from the distal ablation electrode hub portion 540 to the proximal end 568A-568F, the serpentine conductive path 580A-580F being formed between a plurality of spaced laterally extending gaps 582A-582F on the radial segments 542A-542F, wherein each of the laterally extending gaps 582A-582F extends only partially across the radial segments 542A-542F.

[0092] It is well known that for methods comprising one or more steps, the order listed is not a limitation of the claims unless there is an explicit or implicit statement to the contrary in the specification or the claims themselves. It is also recognized that the methods shown are merely some examples among the many examples disclosed, and certain steps may be added or omitted without departing from the scope of this disclosure. Such steps may include combinations of devices, systems, or methods or components thereof, as well as what is well known, normal, and conventional in the art.

[0093] The connecting lines shown in the various figures included herein are intended to illustrate 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 a real system. However, benefits, advantages, solutions to problems, and any element that may cause any benefit, advantage, or solution to occur or become more apparent should not be construed as a critical, essential, or fundamental feature or element. Therefore, the scope is limited only by the appended claims, wherein references to elements in the singular form, unless expressly stated otherwise, are not intended to mean “one and only one” but rather “one or more.” Furthermore, where phrases similar to “at least one of A, B, or C” are used in the claims, it is intended that such phrase be interpreted as meaning that A may be present alone in an embodiment, B may be present alone in an embodiment, C may be present alone 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.

[0094] In the detailed description herein, references to "an embodiment," "embodiment," "exemplary embodiment," etc., indicate that the described embodiment may include specific features, structures, or characteristics, but each embodiment may not necessarily include specific features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when specific features, structures, or characteristics are described in connection with embodiments, it should be noted that those skilled in the art, benefiting from this disclosure, can influence these features, structures, or characteristics in conjunction with other embodiments (whether explicitly described or not). Upon reading the description, it will be apparent to those skilled in the art how this disclosure can be implemented in alternative embodiments.

[0095] Furthermore, no element, component, or method step in this disclosure is intended to be offered to the public, whether or not it is expressly recited in the claims. No element of any claim herein should be interpreted under 35 U.S.SC 112(f) unless it is expressly recited using the phrase “apparatus for…”. As used herein, the terms “comprise,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements may include not only those elements but also other elements not expressly listed or inherent to such a process, method, article, or apparatus.

[0096] Various modifications and additions may be made to the exemplary embodiments discussed without departing from the scope of this disclosure. For example, while the embodiments described above relate to specific features, the scope of this disclosure also includes embodiments with different combinations of features and embodiments that do not include all of the described features. Therefore, the scope of this disclosure is intended to cover all such alternatives, modifications, and variations, and all equivalents thereof, as falling within the scope of the claims.

Claims

1. A catheter for ablation of cardiac tissue via irreversible electroporation, the catheter comprising: A tubular shaft having a distal end; An electrode assembly extending distally from the distal end of the tubular shaft, the electrode assembly defining a distally located flexible central hub portion and a plurality of flexible splines, each flexible spline including a distal portion extending proximally from the central hub portion, a proximal portion attached to and constrained by the shaft, and an intermediate portion between the proximal portion and the distal portion. The distal ablation electrode includes an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of which extends longitudinally along at least one segment of the corresponding middle portion of the flexible spline to the corresponding proximal end. Each of the radial segments of the ablation electrode includes a first longitudinal side, a second longitudinal side, and a width extending between the first longitudinal side and the second longitudinal side. Each radial segment of the ablation electrode includes: A first series of gaps, spaced apart from each other along the length of the radial segment of the ablation electrode, and extending partially across the width of the radial segment of the ablation electrode from the first longitudinal side toward the second longitudinal side; and The second series of gaps are spaced apart from each other along the length of the radial segment of the ablation electrode and extend from the second longitudinal side toward the first longitudinal side partially across the width of the radial segment of the ablation electrode.

2. The catheter according to claim 1, wherein, The electrode assembly includes a flexible circuit having a flexible circuit hub and multiple flexible circuit branches, the multiple flexible circuit branches being integrally formed with the flexible circuit hub and extending proximally from the flexible circuit hub.

3. The catheter according to claim 2, wherein, The electrode assembly includes a shape memory support member coupled to the flexible circuit.

4. The catheter according to claim 3, wherein, The shape memory support member faces inward and is opposite to the ablation electrode on the electrode assembly.

5. The catheter according to any one of claims 3 and 4, wherein, The supporting structure is made of nickel-titanium alloy.

6. The catheter according to any one of claims 1 to 5, wherein, The first series of gaps and the second series of gaps are formed by mechanical cutting.

7. The catheter according to any one of claims 1 to 5, wherein, The first series of gaps and the second series of gaps are formed by laser cutting.

8. The catheter according to any one of claims 1 to 7, wherein, The first series of gaps and the second series of gaps are filled with a coating.

9. The catheter according to claim 8, wherein, The coating comprises parylene.

10. The catheter according to any one of claims 1 to 9, wherein, The distal ablation electrode is made of copper.

11. The catheter according to any one of claims 1 to 10, wherein, The flexible circuit also includes a hub sensing electrode centrally located on the hub of the flexible circuit.

12. The catheter according to any one of claims 1 to 11, further comprising: One or more axial electrodes located on the proximal side of the distal end of the tubular outer shaft.

13. The catheter according to claim 12, wherein, The distal ablation electrode and the one or more axial electrodes are configured to define an anodic / cathode electrode pair for delivering electroporation ablation energy to the target tissue.

14. The catheter according to any one of claims 1 to 13, wherein, The electrode assembly further includes 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 is disposed above a corresponding one of the support member branches.

15. The catheter according to claim 14, wherein, The electrode assembly includes a first region, the first region including an adhesive layer disposed between the flexible circuit and the support member and mechanically attaching the flexible circuit to the support member; And a second region, in which the flexible circuit and the support member are not directly mechanically attached together.

16. A catheter for ablation of cardiac tissue via irreversible electroporation, the catheter comprising: A tubular shaft having a distal end; An electrode assembly extending distally from the distal end of the tubular shaft, the electrode assembly defining a distally located flexible central hub portion and a plurality of flexible splines, each flexible spline including a distal portion extending proximally from the central hub portion, a proximal portion attached to and constrained by the shaft, and an intermediate portion between the proximal portion and the distal portion. The distal ablation electrode includes an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of which extends longitudinally along at least one segment of the corresponding middle portion of the flexible spline to the corresponding proximal end. Each of the radial segments of the ablation electrode includes a first longitudinal side, a second longitudinal side, and a width extending between the first longitudinal side and the second longitudinal side. Each radial segment of the ablation electrode includes: A first series of gaps, spaced apart from each other along the length of the radial segment of the ablation electrode, and extending partially across the width of the radial segment of the ablation electrode from the first longitudinal side toward the second longitudinal side; and The second series of gaps are spaced apart from each other along the length of the radial segment of the ablation electrode and extend from the second longitudinal side toward the first longitudinal side partially across the width of the radial segment of the ablation electrode.

17. The catheter according to claim 16, wherein, The electrode assembly includes a flexible circuit having a flexible circuit hub and multiple flexible circuit branches, the multiple flexible circuit branches being integrally formed with the flexible circuit hub and extending proximally from the flexible circuit hub.

18. The catheter according to claim 17, wherein, The electrode assembly includes a shape memory support member coupled to the flexible circuit.

19. The catheter according to claim 18, wherein, The shape memory support member faces inward and is opposite to the ablation electrode on the electrode assembly.

20. The catheter according to claim 18, wherein, The supporting structure is made of nickel-titanium alloy.

21. The catheter according to claim 16, wherein, The first series of gaps and the second series of gaps are formed by mechanical cutting.

22. The catheter according to claim 16, wherein, The first series of gaps and the second series of gaps are formed by laser cutting.

23. The catheter according to claim 16, wherein, The first series of gaps and the second series of gaps are filled with a coating.

24. The catheter according to claim 23, wherein, The coating is parylene.

25. The catheter according to claim 16, wherein, The distal ablation electrode is made of copper.

26. The catheter according to claim 16, wherein, The flexible circuit also includes a hub sensing electrode centrally located on the hub of the flexible circuit.

27. The catheter according to claim 16, further comprising: One or more axial electrodes located on the proximal side of the distal end of the tubular outer shaft.

28. The catheter according to claim 27, wherein, The distal ablation electrode and the one or more axial electrodes are configured to define an anodic / cathode electrode pair for delivering electroporation ablation energy to the target tissue.

29. The catheter according to claim 16, wherein, The electrode assembly further includes 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 is disposed above a corresponding one of the support member branches.

30. A catheter for ablation of cardiac tissue via irreversible electroporation, the catheter comprising: A tubular outer shaft having a proximal end and an opposing distal end; An electrode assembly extending distally from the outer shaft, the electrode assembly defining a distally located central hub portion and a plurality of splines, each spline including a distal portion extending proximally from the central hub portion, a proximal portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal portion and the distal portion, the electrode assembly comprising: A support member, the support member being formed of a hyperelastic material, and having a support member hub and a plurality of support member branches, the support member branches being integrally formed with the support member hub and extending proximally from the support member hub; A flexible circuit is disposed above the outer surface of the support member and has a flexible circuit hub disposed above the hub of the support member and a plurality of flexible circuit branches integrally formed with the flexible circuit hub, each of the flexible circuit branches being disposed above a corresponding branch of the support member. The flexible circuit further includes: The outwardly oriented distal ablation electrode includes an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of which extends longitudinally along at least one segment of the corresponding middle portion of the flexible spline to the corresponding proximal end. Each of the radial segments of the ablation electrode includes a longitudinally extending serpentine conductive path that passes through a plurality of laterally extending gaps from the hub portion of the ablation electrode to the proximal end.

31. The catheter according to claim 30, wherein, The lateral gap is formed by mechanical cutting.

32. The catheter according to claim 30, wherein, The laterally extending gaps are filled with a coating.

33. The catheter according to claim 30, wherein, The distal ablation electrode is made of copper.

34. A catheter for ablation of cardiac tissue via irreversible electroporation, the catheter comprising: A tubular outer shaft having a proximal end and an opposing distal end; as well as An electrode assembly extending distally from the distal end of the tubular shaft, the electrode assembly defining a distally located flexible central hub portion and a plurality of flexible splines, each flexible spline including a central portion, the electrode assembly comprising: The outwardly oriented distal ablation electrode includes an ablation electrode hub portion located on the flexible central hub portion and a plurality of ablation electrode radial segments, each of which extends longitudinally along at least one segment of the corresponding middle portion of the flexible spline to the corresponding proximal end. Each of the radial segments of the ablation electrode includes a longitudinally extending conductive path from the hub portion of the ablation electrode to the proximal end, which passes through a plurality of laterally extending gaps that extend only partially across the radial segment.

35. The catheter according to claim 34, wherein, The laterally extending gaps are filled with a coating.

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