Wide-area focal ablation catheter

Abstract

A catheter for ablating cardiac tissue by irreversible electroporation, comprising a tubular outer shaft and an electrode assembly extending distally from the distal end of the outer shaft. The electrode assembly defines a distally located central hub portion and a plurality of splines extending proximal from the central hub portion. The electrode assembly includes a flexible circuit having a flex circuit hub and a plurality of flex circuit branches integrally formed with the flex circuit hub and extending proximal from the flex circuit hub, the flexible circuit further including an outward-facing ablation electrode comprising an ablation electrode hub portion positioned on the flex circuit hub and a plurality of ablation electrode branches integrally formed with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal along a corresponding portion of the plurality of flex circuit branches and terminating at the proximal end of the ablation electrode.

Description

Technical Field

[0001] The present disclosure relates to medical systems and methods for ablating a patient's tissue. More specifically, the present disclosure relates to medical systems and methods for ablation of tissue by electroporation.

Background Art

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

[0003] Another ablation technique uses electroporation. In electroporation or electro-permeabilization, an electric field is applied to cells to increase the permeability of the cell membrane. Electroporation can be reversible or irreversible depending on the strength of the electric field. When electroporation is reversible, the increased cell membrane permeability can be used to introduce chemicals, drugs, and / or deoxyribonucleic acid (DNA) into the cells before the cells heal and recover. When electroporation is irreversible, the affected cells die by apoptosis.

[0004] Irreversible electroporation can be used as a non-thermal ablation technique. In irreversible electroporation, a short-duration high-voltage pulse train is used to generate an electric field strong enough to kill cells by apoptosis. In cardiac tissue ablation, irreversible electroporation may be a safe and effective alternative to the indiscriminate cell death of thermal ablation techniques such as RF ablation and cryoablation. Irreversible electroporation can be used to kill target tissues such as myocardial tissue by using an electric field intensity and duration that kills the target tissue but does not permanently damage other cells or tissues such as myocardial tissue, red blood cells, vascular smooth muscle tissue, endothelial tissue, and nerve cells. Improved apparatus and methods for performing cardiac tissue ablation by irreversible electroporation are still needed. [Overview of the project]

[0005] Example 1 is a catheter for ablating cardiac tissue by irreversible electroporation, comprising a tubular outer shaft and an electrode assembly. The tubular outer shaft has a proximal end and a distal end on the opposite side. The electrode assembly defines a central hub portion extending distally from the distal end of the outer shaft and positioned distally, and a plurality of splines, each of which includes a distal end portion extending proximal from the central hub portion, a proximal end portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal and distal end portions. The electrode assembly further includes a flexible circuit having a flex circuit hub and a plurality of flex circuit branches integrally formed with the flex circuit hub and extending proximal to the flex circuit hub, the flexible circuit further includes an outward-facing ablation electrode, the ablation electrode having an ablation electrode hub portion positioned on the flex circuit hub and a plurality of ablation electrode branches integrally formed with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal to a corresponding portion of the plurality of flex circuit branches and terminating at the proximal end of the ablation electrode.

[0006] In Example 2, the catheter according to claim 1 further includes a plurality of spline sensing electrodes arranged on each flex circuit branch. In Example 3, in the catheter according to claim 2, one or more of the multiple spline detection electrodes on each flex circuit branch are positioned within the surface of the ablation electrode branch on each flex circuit branch and are electrically insulated from the ablation electrode.

[0007] In Example 4, in the catheter according to claim 2 or 3, one or more of the multiple spline detection electrodes are positioned proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

[0008] In Example 5, in the catheter according to any one of claims 1 to 4, the proximal end of each ablation electrode branch has a curved shape. In Example 6, in any of the catheters in Examples 1 to 5, the distal end portion of each spline has a maximum distal width, and the intermediate portion of each spline has a maximum intermediate width that is greater than the maximum distal width.

[0009] In Example 7, the catheter according to claim 6, the intermediate portion of each spline includes one or more scalloped regions, and each scalloped region has a scalloped region width smaller than the maximum width of the intermediate portion.

[0010] In Example 8, the catheter according to claim 7 is configured such that at least one scalloped region is located in a portion of each spline where the corresponding ablation electrode branch is positioned.

[0011] In Example 9, in the catheter according to any one of claims 1 to 8, each ablation electrode branch includes one or more ablation electrode branch openings, and one of a plurality of spline detection electrodes is located within one of the corresponding proximal ablation electrode branch openings.

[0012] In Example 10, in the catheter according to claim 9, each ablation electrode branch opening is defined by the corresponding inner surface of the ablation electrode branch, and the outer surface of the spline detection electrode positioned within the corresponding ablation electrode branch opening is spaced apart from the corresponding inner surface of the ablation electrode branch.

[0013] In Example 11, in any of the catheters from Examples 1 to 10, the flex circuit further includes a hub sensing electrode positioned in the center of the flex circuit hub. Example 12 further comprises one or more shaft electrodes positioned close to the distal end of a tubular outer shaft, in the catheter according to any one of claims 1 to 11.

[0014] In Example 13, the catheter according to claim 12 is configured such that the ablation electrode and one or more shaft electrodes form an anode / cathode electrode pair for delivering electroporation ablation energy to the target tissue.

[0015] In Example 14, in any catheter of Examples 1 to 14, the electrode assembly further includes a support member, the support member having a support member hub and a plurality of support member branches extending proximal to the support member hub, the flex circuit hub being positioned on the support member hub, and each of the plurality of flex circuit branches being positioned on a corresponding one of the plurality of support member branches.

[0016] In Example 15, the catheter according to claim 15 includes a first region which is located between the flexible circuit and the support member and includes an adhesive layer which mechanically attaches 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 to each other.

[0017] In Example 16, a catheter for ablating cardiac tissue by irreversible electroporation comprises a tubular outer shaft and an electrode assembly. The tubular outer shaft has a proximal end and an opposite distal end. The electrode assembly extends distally from the distal end of the outer shaft and defines a central hub portion located distally, and a plurality of splines, each of which includes a distal end portion extending proximal from the central hub portion, a proximal end portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal and distal end portions. The electrode assembly further includes a support member and a flexible circuit. The support member has a support member hub and a plurality of support member branches extending proximal from the support member hub. The flexible circuit has a flex circuit hub positioned on the outer surface of a support member and on a support member hub, and a plurality of flex circuit branches, each of the plurality of flex circuit branches positioned on a corresponding one of the plurality of support member branches, and the flexible circuit further includes an ablation electrode, each of which has an ablation electrode hub portion positioned on the flex circuit hub and a plurality of ablation electrode branches formed integrally with the ablation electrode hub portion, each of which has an ablation electrode branch extending proximal along a corresponding portion of the plurality of flex circuit branches and terminating at the proximal end of the ablation electrode.

[0018] In Example 17, the catheter according to claim 16 further includes a plurality of spline sensing electrodes arranged on each flex circuit branch, one or more of the plurality of spline sensing electrodes on each flex circuit branch being located within the surface of the corresponding ablation electrode branch arranged on the flex circuit branch and electrically insulated from the ablation electrode.

[0019] In Example 18, the catheter according to claim 17 has a curved shape at the proximal end of each ablation electrode branch. In Example 19, in the catheter according to claim 17, one or more of the plurality of spline sensing electrodes are disposed proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

[0020] In Example 20, in the catheter according to claim 17, each ablation electrode branch includes one or more ablation electrode branch openings, and one of the plurality of spline sensing electrodes is disposed within a corresponding one of the ablation electrode branch openings.

[0021] In Example 21, in the catheter according to claim 20, each ablation electrode branch opening is defined by a corresponding inner circumferential surface of the ablation electrode branch, and the outer circumferential surface of the spline sensing electrode disposed within the corresponding ablation electrode branch opening is spaced from the corresponding inner circumferential surface of the ablation electrode branch.

[0022] In Example 22, in the catheter according to claim 17, the distal end portion of each spline has a distal portion maximum width, and the intermediate portion of each spline has an intermediate portion maximum width that is greater than the distal portion maximum width.

[0023] In Example 23, in the catheter according to claim 22, the intermediate portion of each spline includes one or more scalloped regions, each scalloped region having a scalloped region width that is less than the maximum width of the intermediate portion, and at least one scalloped region is disposed on a portion of each spline where the corresponding ablation electrode branch is disposed.

[0024] In Example 24, in the catheter according to claim 17, the flexible circuit further includes a hub sensing electrode disposed centrally on the flex circuit hub. The catheter according to claim 17, further comprising one or more shaft electrodes disposed proximate to the distal end of the tubular outer shaft in Example 25.

[0025] In Example 26, the catheter according to claim 25 is configured such that the ablation electrode and one or more shaft electrodes form an anode / cathode electrode pair for delivering electroporation ablation energy to the target tissue.

[0026] Example 27 provides a catheter for ablating cardiac tissue by irreversible electroporation, comprising a tubular outer shaft and an electrode assembly. The tubular outer shaft has a proximal end and an opposite distal end. The electrode assembly extends distally from the distal end of the outer shaft and defines a central hub portion located distally, and a plurality of splines, each of which includes a distal end portion extending proximal from the central hub portion, a proximal end portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal and distal end portions. The electrode assembly further 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 the support member hub and extending proximal from the support member hub. The flexible circuit is arranged on the outer surface of a support member, and the flexible circuit has a flex circuit hub arranged on a support member hub, and a plurality of flex circuit branches formed integrally with the flex circuit hub, each of the plurality of flex circuit branches arranged on one of the plurality of support member branches. The flexible circuit further includes an ablation electrode comprising an ablation electrode hub portion arranged on a flex circuit hub, and a plurality of ablation electrode branches formed integrally with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal to one of the plurality of flex circuit branches, and a plurality of spline detection electrodes, one or more of the plurality of spline detection electrodes arranged within the surface of each of the plurality of ablation electrode branches and electrically insulated from the ablation electrode.

[0027] In Example 28, in the catheter according to claim 27, the distal end portion of each spline has a maximum distal portion width, and the intermediate portion of each spline has a maximum intermediate portion width that is greater than the maximum distal portion width.

[0028] In Example 29, in the catheter according to claim 28, the intermediate portion of each spline includes one or more scalloped regions, each scalloped region having a scalloped region width that is smaller than the maximum width of the intermediate portion, and at least one scalloped region is disposed on a part of each spline where the corresponding ablation electrode branch is disposed.

[0029] In Example 30, in the catheter according to claim 29, one or more of the plurality of spline sensing electrodes are disposed proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

[0030] In Example 31, in the catheter according to claim 30, the flexible circuit further includes a hub sensing electrode disposed at the center of the flex circuit hub. Example 32 provides a catheter for ablating cardiac tissue by irreversible electroporation, comprising a tubular outer shaft and an electrode assembly. The tubular outer shaft has a proximal end and an opposite distal end. The electrode assembly comprises a flexible circuit having a central flex circuit hub distally located from the distal end of the outer shaft and a plurality of flex circuit branches extending proximal from the hub portion, each of the plurality of flex circuit branches including a proximal end portion that at least partially forms an electrode assembly spline and is attached to and constrained by the outer shaft. The flexible circuit further includes an ablation electrode comprising an ablation electrode hub portion located on the flex circuit hub and a plurality of ablation electrode branches integrally formed with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal along a corresponding portion of the plurality of flex circuit branches and terminating at the proximal end.

[0031] In Example 33, in the catheter of Example 32, the flexible circuit further includes a plurality of spline sensing electrodes arranged on each flex circuit branch, one or more of the plurality of spline sensing electrodes on each flex circuit branch being located within the surface of the corresponding ablation electrode branch on the flex circuit branch and electrically insulated from the ablation electrode.

[0032] In Example 34, in the catheter according to claim 33, one or more of the multiple spline detection electrodes are positioned proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

[0033] In Example 35, the catheter according to claim 34 further includes a hub sensing electrode located in the center of the flex circuit hub. While several embodiments are disclosed, further embodiments of the Disclosure will become apparent to those skilled in the art from the following detailed description illustrating and describing exemplary embodiments of the Disclosure. Accordingly, the drawings and detailed description should be considered illustrative and not restrictive. [Brief explanation of the drawing]

[0034] [Figure 1] This figure shows an exemplary clinical environment for treating a patient and treating a patient's heart using an electrophysiological system according to embodiments of the subject matter of this disclosure. [Figure 2A] This is a perspective view of the distal portion of a splined catheter for use in the electrophysiological system shown in Figure 1, according to an embodiment of the subject matter of this disclosure. [Figure 2B] Figure 1 is an end view of the distal portion of a splined catheter for use in the electrophysiological system according to an embodiment of the subject matter of this disclosure. [Figure 2C] This is a partial plan view of a two-dimensional electrode assembly of a splined catheter according to an embodiment of the subject matter of the present disclosure. [Figure 2D] Figures 2A to 2C are enlarged plan views of a portion of the spline of the electrode assembly shown in Figures 2A to 2C, according to an embodiment of the subject matter of this disclosure. [Figure 2E] These are schematic cross-sectional views of a portion of the spline of the electrode assembly shown in Figures 2A to 2C, according to an embodiment of the subject matter of this disclosure. [Figure 2F] Figures 2A-2C show schematic diagrams of alternative spline designs that may be used in the electrode assemblies. [Figure 2G] Figure 1 is a partial plan view of an alternative electrode assembly for use in the catheter, shown in two dimensions to illustrate the placement of the electrode assembly. [Figure 2H] Figure 2G is a schematic cross-sectional view of a portion of the electrode assembly shown. [Figure 2I] Figure 2G is a schematic cross-sectional view of a portion of the electrode assembly shown. [Figure 3A]These are schematic diagrams of exemplary electric fields generated using the electrode assemblies illustrated in Figures 2A to 2D according to embodiments of the subject matter of this disclosure. [Figure 3B] These are schematic diagrams of exemplary electric fields generated using the electrode assemblies illustrated in Figures 2A to 2D according to embodiments of the subject matter of this disclosure. [Figure 4A] This figure shows the distal portion of the catheter in Figure 1 in an exemplary setting of use within a patient's cardiac chamber, according to an embodiment of the subject matter of this disclosure. [Figure 4B] This figure shows the distal portion of the catheter in Figure 1 in an exemplary setting of use within a patient's cardiac chamber, according to an embodiment of the subject matter of this disclosure. [Modes for carrying out the invention]

[0035] While this disclosure can be adapted to various modifications and alternative forms, specific embodiments are shown in the drawings as examples and are described in detail below. However, the intent is not to limit this disclosure to the specific embodiments described. Rather, this disclosure is intended to encompass all modifications, equivalents, and alternative forms that fall within the scope of this disclosure as defined by the appended claims.

[0036] For the purpose of facilitating an understanding of the principles of this disclosure, examples shown in the drawings described below will be referenced. The exemplary examples disclosed herein are not intended to be exhaustive or to limit this disclosure to the exact forms disclosed for carrying out the inventions described below. Rather, these exemplary embodiments are selected and described so that those skilled in the art can use their teachings. Using multiple (e.g., all) features in a given example across all examples does not exceed the scope of this disclosure. Accordingly, no drawing should be construed as having any dependencies or requirements relating to any single component or combination of components shown. In addition, various components shown in a given drawing may, in some examples, be integrated with various other components shown (and / or not shown), all of which are considered to be within the scope of this disclosure.

[0037] The terms “couples,” “coupled,” “connected,” and “attached,” along with their variations, are used to include both 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 (for example, components are “coupled” through at least a third component), but still cooperate or interact with each other.

[0038] Throughout this disclosure and in the claims, numerical terms such as "first" and "second" are used in reference to various components or features. Such use is not intended to indicate an order of components or features. Rather, numerical terms are used to help the reader identify the components or features being referenced, and should not be narrowly interpreted as providing a specific order of components or features.

[0039] Figure 1 is a schematic diagram illustrating an exemplary clinical environment 10 for treating a patient 20 and the patient 20's heart 30 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 electro-anatomical mapping (EAM) system 70, the electro-anatomical mapping (EAM) system 70 including a localization field generator 80, a mapping and navigation controller 90, and a display 92. The clinical environment 10 also includes additional equipment (e.g., imaging equipment 94 (represented by a C-arm)) and various controller elements (e.g., a foot controller 96) configured to allow an operator to control various aspects of the electrophysiological system 50. As will be understood by those skilled in the art, the clinical environment 10 may have other components and arrangements of components not shown in Figure 1.

[0040] 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. In addition, the electroporation catheter system 60 includes various connecting elements (e.g., cables, umbilicals) that 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 connecting elements is not critically important to the disclosure, and those skilled in the art will recognize that the various components described herein can be interconnected in various ways.

[0041] In the embodiment, the introducer sheath 110 is operable to provide a delivery conduit through which an electroporation catheter 100, in particular all or part of its distal portion 105, can be deployed to a specific target site within the patient's heart 30.

[0042] In this embodiment, the electroporation catheter system 60 is configured to deliver electric field energy to target tissue within the patient's heart 30 to induce tissue apoptosis, thereby preventing the tissue from conducting electrical signals.

[0043] The electroporation console 130 is configured to control the 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 and / or perform the functional aspects of the electroporation catheter system 60. In embodiments, the memory may be part of one or more controllers, microprocessors, and / or computers, and / or part of a memory capacity accessible through a network such as the World Wide Web. In embodiments, the electroporation console 130 includes hardware, software, and / or firmware of a pulse generator configured to generate electrical pulses of a predetermined waveform, which are transmitted to electrodes on the electroporation catheter 100 to generate an electric field sufficient to achieve a desired clinical effect, in particular, ablation of target tissue by irreversible electroporation. In embodiments, the electroporation console 130 can deliver pulse waveforms to the electroporation catheter 100 in unipolar or bipolar operating modes, as will be described in further detail herein.

[0044] The EAM system 70 can operate to track the positions of various functional components of the electroporation catheter system 60 and generate high-fidelity three-dimensional anatomical and electroanatomical maps of the cardiac chambers of interest. In embodiments, the EAM system 70 may be the RHYTHMIA® HDx mapping system sold by Boston Scientific Corporation. In embodiments, the mapping and navigation controller 90 of the 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 the EAM system 70, and in embodiments, the memory may be part of one or more controllers, microprocessors, and / or computers, and / or part of memory capacity accessible through a network such as the World Wide Web.

[0045] As will be understood by those skilled in the art, the illustration of the electrophysiological system 50 shown in Figure 1 is intended to provide a general overview of the various components of the system 50 and is not intended in any way 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 (e.g., breakout boxes, workstations, etc.) may, or are likely to, be included in the electrophysiological system 50.

[0046] The EAM system 70 generates a localization field via a field generator 80 to form a localization volume around the heart 30, and one or more location sensors or sensing elements on the device being tracked (e.g., sensors or sensing elements on the electroporation catheter 100) generate outputs that can be processed by the mapping and navigation controller 90 to track the location of the sensors within the localization volume, and thus the location of the corresponding device. In the illustrated embodiment, device tracking is performed using a magnetic tracking technique, the field generator 80 is a magnetic field generator that generates a magnetic field that forms the localization volume, and the location sensors on the device being tracked are magnetic field sensors.

[0047] In other embodiments, impedance tracking methods may be used to track the locations of various devices. In such embodiments, the localization field is an electric field generated, for example, by an external field generator arrangement (e.g., surface electrodes), by an internal device or an intracardiac device (e.g., an intracardiac catheter), or both. In these embodiments, the localization element may constitute electrodes on the device being tracked that generate outputs received and processed by a mapping and navigation controller 90 in order to track the locations of various localization electrodes within a localization volume.

[0048] In some embodiments, the EAM system 70 includes both magnetic tracking and impedance tracking capabilities. In such embodiments, impedance tracking accuracy can be enhanced by first creating a map of the electric fields induced by an electric field generator in the cardiac chamber of interest using a probe equipped with a magnetic position sensor, as is possible in some cases using the aforementioned RHYTHMIA HDx® mapping system. One exemplary probe is the INTELLAMAP ORION® mapping catheter, marketed by Boston Scientific Corporation.

[0049] Regardless of the tracking method used, the EAM system 70 utilizes the location information of various tracked devices and cardiac electrical activity acquired, for example, by an electroporation catheter 100 equipped with sensing electrodes or another catheter or probe, to generate a detailed three-dimensional geometric anatomical map or representation of the cardiac chambers, as well as an electroanatomical map in which the cardiac electrical activity of interest is superimposed on the geometric anatomical map, and displays these on the display 92. Furthermore, the EAM system 70 can generate graphic representations of various tracked devices within the geometric anatomical map and / or electroanatomical map.

[0050] Embodiments of this disclosure provide systems, apparatus, and methods for the selective and rapid application of a pulsed electric field to ablate tissue by irreversible electroporation. Generally, the systems, apparatus, and methods described herein can be used to generate a high electric field intensity in a desired region of interest while reducing peak electric field values ​​in other regions to reduce unwanted tissue damage and electrical arcing. The irreversible electroporation systems described herein include a signal generator and a processor, the processor of which may be configured to apply one or more voltage pulse waveforms to a selected group of electrodes of the ablation apparatus to deliver energy to the region of interest (e.g., ablation energy of tissue groups in pulmonary vein openings or pulmonary venous sinuses). The pulse waveforms disclosed herein may assist in the 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 apparatus may have insulated conductors configured to maintain a voltage potential of several hundred to several thousand volts. The electrodes may be independently addressable, allowing each electrode to be controlled independently of any other electrode in the device (e.g., energy can be delivered to it). In this way, the electrodes can synergistically deliver different energy waveforms at different timings to perform electroporation of tissue.

[0051] 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 reducing the total energy delivered and resulting in more effective ablation. In some embodiments, the voltage pulse waveforms disclosed herein may be hierarchical and may have a nested structure. For example, the pulse waveform may include a hierarchical grouping of pulses having a relevant time scale. In some embodiments, the methods, systems, and apparatus disclosed herein may include one or more of the methods, systems, and apparatus described in International Application PCT / US2016 / 057664, filed on October 19, 2016, titled "Systems, Apparatus and Methods for Delivery of Ablationive Energy to Tissue," the entirety of which is incorporated herein by reference.

[0052] Figures 2A and 2B are a partial perspective view and an end view, respectively, of an electroporation catheter 200 having a distal portion 205 according to an embodiment of the present disclosure. The electroporation catheter 200 corresponds to the electroporation catheter 100 described with respect to Figure 1. The electroporation catheter 200 has a tubular outer shaft 202 having a distal shaft end 209, and an electrode assembly 210 extending distally from the distal end 209 of the outer shaft 202. In embodiments, the electrode assembly 210 is configured to self-expand from a contracted state when confined within a delivery sheath to a predetermined expanded state that forms an internal space 212. As described in more detail herein, the electrode assembly 210 includes an ablation electrode configured to receive pulsed electrical signals / pulse waveforms from an electroporation console 130 (Figure 1) and thereby generate a pulsed electric field sufficient to ablate target tissue via irreversible electroporation. Furthermore, the electrode assembly 210 further includes a plurality of mapping and sensing electrodes configured to detect cardiac electrical signals, locate the electrode assembly 210 within the patient's anatomical structure (e.g., via the EAM system 70 in Figure 1), and determine its proximity to target tissue within the anatomical structure.

[0053] Overall, the electrode assembly 210 and other electrode assembly embodiments described herein within the scope of this disclosure are primarily designed for the creation of relatively localized ablation (i.e., focal lesions) compared to the relatively large-diameter annular ablation created in pulmonary vein isolation procedures. However, those skilled in the art will understand that the teachings of this disclosure can be readily adapted to catheters capable of large-diameter annular ablation. The designs of the various electrode assembly embodiments described herein can provide clinicians with a combination of broad capabilities for unipolar and bipolar focal pulsed-field ablation of cardiac tissue and the ability to perform localized, high-fidelity sensing of cardiac tissue (i.e., at the location where pulsed-field ablation energy is delivered) for purposes such as evaluating ablation or conduction block and determining tissue contact.

[0054] Figure 2C is a partial plan view of the electrode assembly 210 of the illustrated electroporation catheter 200, shown in two dimensions to illustrate the arrangement of the electrode assembly 210. Referring together to Figures 2A to 2C, in the illustrated embodiment, the electrode assembly 210 as a whole has a distally located central hub portion 214 and a plurality of splines 216A to 216F extending proximal from the central hub portion 214. Further illustrated, each individual spline 216A to 216F has a distal end portion 217A to 217F, a proximal end portion 218A to 218F, and an intermediate portion 219A to 219F extending between the distal end portions 217A to 217F and the proximal end portions 218A to 218F. As illustrated, each of the proximal end portions 218A to 218F is attached to and constrained by the distal end 209 of the outer shaft 202. As further illustrated, in the illustrated embodiment, the intermediate portions 219A to 219F of each spline 216A to 216F have a greater lateral width than the respective lateral widths of the individual distal portions 217A to 217F. In the embodiment, the specific geometric shapes of the splines 216A to 216F and related components (e.g., ablation electrodes and mapping electrodes) are optimized to provide desired mechanical and therapeutic / diagnostic functions.

[0055] In the illustrated embodiment, the splines 216A to 216F consist of a support member 220 and a flexible circuit 222 fixed to and positioned on the outer surface of the support member 220. The support member 220 functions, in particular, as the main structural support of the electrode assembly 210 and therefore primarily defines the mechanical properties of the electrode assembly 210. In the embodiment, the support member 220 is formed from a superelastic material (metal or polymer) to impart desired mechanical / structural properties to the electrode assembly 210. In the embodiment, the support member 220 is formed from a superelastic metal alloy (e.g., nickel-titanium alloy).

[0056] The support member 220 includes a support member hub 224 and a plurality of support member branches (for illustrative purposes only, only support member branch 226A is reference-labeled in Figure 2A). In embodiments, the support member branches are integrally formed with the support member hub 224 and extend proximal to the support member hub 224. For example, the entire support member 200 may be cut from a single sheet of material using conventional manufacturing techniques. This integral structure provides robust structural properties, such as selective flexibility and excellent fatigue resistance, particularly in areas subjected to relatively high stress during the manufacture and use of the electroporation catheter 200. By forming the support member 220 from a superelastic material such as a nickel-titanium alloy, it is possible to configure the support member 220 to take on a desired unconstrained shape, as shown in Figure 2A, due to the shape memory properties of the material, and to provide sufficient flexibility necessary to contract the electrode assembly 210 into the delivery sheath. In embodiments, the support member branches may be selectively configured along their longitudinal direction to adjust the mechanical properties of the electrode assembly 210.

[0057] The flexible circuit 222 includes a flexible circuit hub 230 and a plurality of flexible circuit branches 234A to 234F. In the embodiment, the flexible circuit hub 230 is positioned on and fixed to the support member hub 224. In the embodiment, the flexible circuit branches 234A to 234F are integrally formed with the flexible circuit hub 230, and each of the flexible circuit branches 234A to 234F is positioned on and fixed to one of the corresponding support member branches. The flexible circuit 222 consists of a layered structure including one or more dielectric substrate layers and conductive traces formed thereon. Similar to the support member 220, the integral structure of the flexible circuit 222 has excellent structural properties by minimizing joints or other discontinuities in areas that are subjected to relatively high stress during use, for example.

[0058] As shown in the figure, the flexible circuit 222 includes an ablation electrode 238 having an ablation electrode hub portion 240 and a plurality of ablation electrode branches 242A to 242F. In the illustrated embodiment, the distal ablation electrode hub portion 240 is located on the flexible circuit hub 230. Furthermore, the plurality of ablation electrode branches 242A to 242F are integrally formed with the ablation electrode hub portion 240. Each of the plurality of ablation electrode branches 242A to 242F extends proximal along a corresponding portion of the plurality of flexible circuit branches 234A to 234F.

[0059] As further illustrated, the flexible circuit 222 includes a plurality of spline detection electrodes 250. In the illustrated embodiment, two of the plurality of spline detection electrodes 250 are located within the periphery of each of the ablation electrode branches 242A to 242F, and one of the plurality of spline detection electrodes 250 is located proximal to each of the ablation electrode branches 242A to 242F on the corresponding flexible circuit branches 234A to 234F. The illustrated configuration is illustrative only, and other embodiments of the catheter 200 may have alternative configurations. Thus, in various embodiments, one or more of the plurality of spline detection electrodes 250 may be located within the periphery of one or more of the ablation electrode branches 242A to 242F and electrically insulated from there, and one or more of the plurality of spline detection electrodes 250 may be located proximal to the ablation electrode branches 242A to 242F on the corresponding flexible circuit branches 234A to 234F. In yet another embodiment, the spline detection electrode 250 may not be located outside the surface of the ablation electrode branches 242A to 242F.

[0060] In some embodiments, the structural functionality of the support member 220 may be provided by a well-designed flexible circuit 222. Thus, although the electrode assembly 210 is described in detail as including the support member 220 as a major structural member, in other embodiments, the support member 220 may be omitted entirely, and the corresponding functionality may be provided by the flexible circuit 222.

[0061] In a particular illustrated embodiment, the electroporation catheter 200 includes a pair of shaft electrodes 256 positioned close to the distal end 209 of an outer shaft 202, and a central post 258 extending distally from the distal end 209 of the outer shaft 202. As shown, the central post 258 partially extends into an internal space 212 and includes a post electrode 260. In an embodiment, the central post 258 may accommodate additional components. For example, in an embodiment, a magnetic navigation sensor (not shown) may be positioned partially or entirely within the central post 258. However, in other embodiments, such a sensor may be positioned at another location on the electroporation catheter 200 (e.g., within the outer shaft 202). In an illustrated embodiment, the electrode assembly 210 further includes a hub sensing electrode 264 centrally positioned on a flex circuit hub 230.

[0062] In the embodiment, one or both of the shaft electrodes 256 may be configured to pair with the ablation electrode 238 to form an anode / cathode ablation electrode pair for generating an ablation electric field in bipolar mode. In the embodiment, the shaft electrodes 256 may have additional functions for use, for example, as an additional sensing electrode for detecting cardiac electrical signals and as a localization sensor for impedance tracking of the electrode assembly 210, but are not limited to these.

[0063] The post-electrode 260 can offer several functional advantages. In one example, the post-electrode 260 can serve as a reference for unipolar electrograms instead of relying on surface ECG patch electrodes as known in the art. The placement of the post-electrode 260 for this purpose positions the reference electrode much closer to the sensed tissue than is possible with conventional surface ECG techniques, thereby advantageously minimizing far-field noise and potentially providing unipolar electrograms much sharper than is possible using surface ECG electrodes. The post-electrode 260 can also be operated to sense and measure other electrical parameters (e.g., the voltage between the post-electrode 260 and the ablation electrode or other sensing electrode on the electrode assembly 210), thereby, in some examples, being able to determine the shape of the electrode assembly in use (including when deformed by forces applied by the heart wall) and provide data that can be used to display shape information via the EAM system 70 (Figure 1).

[0064] In this embodiment, the hub sensing electrode 264 enables tissue surface mapping to be performed in a "forward" direction, eliminating the need to manipulate the electrode assembly 210 to position the spline sensing electrode 250 relative to or in close proximity to the tissue to be mapped. By including the hub sensing electrode 264, the bipolar sensing capability is further enhanced in the illustrated embodiment by providing six additional bipolars when paired with any of the furthest spline sensing electrodes 250.

[0065] Figure 2D is an enlarged plan view of a portion of the spline 216A, ablation electrode branch 242A, and flex circuit branch 234A according to an embodiment of the present disclosure. The structural features shown in Figure 2D are representative of the splines 216A-216F, ablation electrode branches 242A-242F, and flex circuit branches 234A-234F.

[0066] As shown in the figure, the distal end portion 217A of the spline 216A has a maximum width WD The spline 216A has an intermediate portion 219A with a maximum width W at the distal end. D Larger than maximum width W I It has. In a particular embodiment shown, the intermediate portion 219A further includes one or more scalloped regions 272 having concave outer edges on both sides of the spline 216A. In the embodiment, the scalloped regions 272 are selectively arranged along the longitudinal direction of the spline 216A, each having the maximum width W of the intermediate portion 219A. I Minimum width W of a scalloped region smaller than this S The scalloped region 272, when present, affects the mechanical properties of the spline 216A (e.g., bending flexibility), for example, facilitating deformation of the spline 216A when in contact with the target tissue and facilitating contraction when the electrode assembly 210 is pulled back into the delivery sheath. However, in some embodiments, the scalloped region 272 is omitted, and the spline 216A has a substantially linear shape along the intermediate portion 219A. In the illustrated embodiment, at least one of the scalloped regions 272 is located within the region of the spline 216A where a portion of the ablation electrode branch 242A is located, and between the spline sensing electrodes 250 located on the ablation electrode branch 242A.

[0067] As shown in the illustration, the ablation electrode branch 242A has a proximal end 274A. In the illustrated embodiment, the proximal end 274A is contoured and shaped to enhance electric field generation and clinical efficacy when the catheter 200 is configured to operate in bipolar energy delivery mode and the ablation electrode 238 and one or both shaft electrodes 256 are paired as a bipolar electrode pair. However, in other embodiments, the proximal end 274A may have a different shape (e.g., semicircular). The position of the proximal end 274A (which, as understood, defines the length of the ablation electrode branch 242A and consequently partially defines the total surface area of ​​the ablation electrode 238) may vary from embodiment to embodiment depending on the needs of the specific clinical requirements required of the catheter 200.

[0068] As further illustrated, the ablation electrode branch 242A includes a plurality of ablation electrode branch openings 278, and one of the spline detection electrodes 250 is positioned within each of the plurality of ablation electrode branch openings 278.

[0069] Figure 2E is a schematic cross-sectional view of spline 216A along the line 2E-2E in Figure 2D, showing an exemplary configuration of spline 216A, flex circuit branch 234A, and ablation electrode branch 242A in the intermediate portion 219A. As illustrated in Figure 2E, spline 216A includes a support member branch 226A, and flex circuit branch 234A is positioned on the support member branch 226A. As further illustrated, flex circuit branch 234A has a layered structure that may be typical of a flexible circuit for use in electrode assemblies of medical devices, unless specifically distinguished herein. In the particular embodiment shown in Figure 2E, flex circuit branch 234A includes a dielectric base layer 280A positioned on the support member branch 226A, an optional inner flexible adhesive layer 282A on the base layer 280A, a conductive trace layer 284A on the adhesive layer 282A (if present), and a dielectric top layer 286A on the conductive trace layer 284A. The dielectric material selected for layers 280A and 286A may be any conventional material (e.g., polyamide) suitable for use in flexible circuits for medical devices. It is emphasized that this disclosure is not limited to the specific stacking configuration of the flexible circuit illustrated in Figure 2E, and that those skilled in the art will readily understand the alternative configurations that may be available.

[0070] As further illustrated in Figure 2E, the ablation electrode branch 242A and the spline detection electrode 250 are positioned on top of the upper layer 286A. In embodiments, electrodes 242A and 250 may have a coating of a suitable biocompatible metal (e.g., gold). In embodiments, the outer surfaces of electrodes 242A and 250 may be treated to provide electrical properties desired for a particular clinical application.

[0071] As shown in Figure 2E, the ablation electrode branch opening 278 is defined by the inner circumferential surface 288 of the ablation electrode branch 242A, and the outer circumferential surface 290 of the spline sensing electrode 250 is positioned at a gap G from the inner circumferential surface 288 of the ablation electrode branch 242A. Conventionally, those skilled in the art have assumed that a dielectric material would be placed between the outer circumferential surface 290 and the inner circumferential surface 288 of the ablation electrode branch 242A to minimize any undesirable effects that may occur when a pulse waveform is delivered to the ablation electrode branch 242A (e.g., bubble formation due to arc discharge or edge effect at the periphery of the ablation electrode branch 242A). However, the inventors of the present disclosure have found that the tendency for bubble formation in the blood pool when a gap G is present is substantially the same as in a configuration in which a dielectric material is placed in this region. These favorable results can be enhanced by selectively adjusting the size of the gap G. In embodiments, the gap G can be in the range of about 0.050 mm to about 0.50 mm. In one embodiment, the gap G is approximately 0.50 millimeters.

[0072] In the embodiments described and illustrated herein, each ablation assembly has six splines. However, it is emphasized that this is for illustrative purposes only, and therefore, those skilled in the art will readily recognize that more or fewer splines may be included for a given clinical application.

[0073] In various embodiments, each of the ablation electrode 238, spline detection electrode 250, shaft electrode 256, and hub detection electrode 264 is separately electrically connected to the control system of the electroporation console 130 (Figure 1) and individually addressable to provide a wide range of ablation and detection modes (e.g., unipolar and bipolar modes). During unipolar ablation operation, the ablation electrode 238 and other electrodes located elsewhere (e.g., dispersed electrodes located on the patient, typically on the back, buttocks, or other suitable anatomical locations, or electrodes on different catheters or probes located outside the ventricle where the electrode assembly 210 is located) are configured to operate with opposite polarities. In one example, the ablation electrode 238 is configured as the anode or cathode, and an extracorporeal dispersed electrode located on a patch on the back is configured as the other of the cathode or anode. Those skilled in the art will readily recognize the wide range of unipolar ablation electrode configurations that can be used. In unipolar mode, the corresponding electric field generated around the ablation electrode 238 has a substantially hemispherical shape, as shown in the exemplary electric field profile in Figure 3A.

[0074] During bipolar ablation, the ablation electrode 238 is configured as an anode (or cathode), and one or both of the shaft electrodes 256 are configured as cathodes (or anodes). The resulting electric field generated in the aforementioned bipolar mode tends to have a three-dimensional hourglass shape, as shown in Figure 3B.

[0075] As those skilled in the art will understand, the spline sensing electrode 250, shaft electrode 256, post-reference electrode 260, or hub sensing electrode 264 can each be individually addressable for bipolar sensing and mapping in any number of combinations. Furthermore, in the embodiment, the aforementioned individual addressability makes it possible to configure either the spline sensing electrode and / or the hub sensing electrode 264 to operate as an ablation electrode in cooperation with the ablation electrode 238 in either unipolar or bipolar mode by the control system.

[0076] Referring again to Figures 2A to 2E, in the embodiment, the geometric shapes and positions of the spline detection electrodes 250 and hub detection electrodes 264 are configured to provide wide-range, high-fidelity detection and mapping capabilities. In the illustrated embodiment, the spline detection electrodes 250 are shown to have a generally oval geometric shape, but in other embodiments, they may have different geometric shapes (e.g., circular, semicircular, elliptical, etc.). In the embodiment, the spline detection electrodes 250 may be arranged at uniform intervals along the length of each spline 216A. In the illustrated embodiment, the farthest spline electrode 250 and the hub detection electrode 264 are arranged closer to each other than, for example, the spline detection electrodes 250 are arranged at intervals from each other along each spline. Similarly, the spacing between the farthest spline detection electrodes 250 on adjacent splines is smaller than the spacing between the more proximal spline detection electrodes 250 on adjacent splines. Therefore, the most distal spline sensing electrode 250 can be used to form a relatively close bipolar when paired with the hub sensing electrode 264 or the corresponding most distal spline sensing electrode on an adjacent spline, thus providing very high-fidelity local sensing of cardiac electrical activity.

[0077] Overall, the design and structure of the electrode assembly 210 are particularly well-suited for generating effective broad-area focal ablation with pulsed-field ablation energy in both unipolar and bipolar modes. In various embodiments, the structural characteristics of the splines allow each spline, ablation electrode, and sensing electrode to flexibly adapt to the target cardiac tissue, improving ablation energy delivery and providing high-fidelity local sensing of the tissue and target therapeutic area.

[0078] Figure 2F schematically illustrates alternative designs of splines 216A1-216A5 that may be used in electrode assemblies 210 according to various embodiments, depicted in the form the electrode assembly 210 takes when fully extended. Those skilled in the art will understand that splines 216A1-216A5 may represent other splines forming the electrode assembly 210 in various embodiments. Overall, the various spline designs in Figure 2F exhibit varying degrees of stiffness when the extended electrode assembly 210 is subjected to axial and / or radial compressive loads (e.g., when biased against cardiac tissue). Therefore, by modifying the structural characteristics of the splines, as will be described in more detail below, the shape of the electrode assembly 210 can be customized under such loads. Furthermore, the various spline designs shown in Figure 2F correspond to various ablation electrode geometries (and the resulting effective surface area) for optimizing pulsed-field ablation energy delivery. In the illustrated embodiment, for ease of explanation, the ablation electrodes for each spline are omitted, and only the spline detection electrode 250 is shown to provide a scale and context indicating the positional relationships of the various structural features described.

[0079] As shown in Figure 2F, the spline 216A1 has an intermediate portion 219A1 that does not have any scalloped regions, and therefore the outer side edge of the intermediate portion 219A1 is substantially straight or linear. In the illustrated embodiment, the intermediate portion 219A1 has a uniform width along its entire length. Generally, embodiments of the spline 216A1 are less flexible under radial or compressive loads than other embodiments illustrated in Figure 2F.

[0080] As further illustrated, the spline 216A2 has an intermediate portion 219A2 having a single scalloped region 272 interposed between two furthest distal spline sensing electrodes 250, the more proximal region of the intermediate portion 219A2 having a substantially uniform width along its longitudinal direction. The inventors of this disclosure have found that the spline 216A2 exhibits an overall stiffness reduction of about 3.07% compared to the spline 216A1 under axial or radial compression.

[0081] As further illustrated, spline 216A3 has an intermediate portion 219A3 having two scalloped regions 272 interposed between two adjacent spline sensing electrodes 250, respectively. Spline 216A3 may be constructed substantially similarly to splines 216A to 216F shown in Figures 2A to 2E and described in the corresponding descriptions. The inventors of this disclosure have found that spline 216A3 exhibits an overall stiffness reduction of about 12.88% compared to spline 216A1 under axial or radial compression.

[0082] As further illustrated, the spline 216A4 has an intermediate portion 219A4 having two scalloped regions 272 interposed between two adjacent spline sensing electrodes 250, and a third scalloped region 273 located in an intermediate-to-proximal transition region 275 located proximal to the most proximal spline sensing electrode 250. The inventors of this disclosure have found that the spline 216A4 exhibits an overall stiffness reduction of approximately 13.91% compared to the spline 216A1 under axial or radial compression.

[0083] As further illustrated, spline 216A5, like spline 216A3, has an intermediate portion 219A5 having two scalloped regions 272 interposed between two adjacent spline sensing electrodes 250, respectively. Spline 216A5 differs from spline 216A3 in that the intermediate-to-proximal transition region 275 has a uniform decrease in width in the proximal direction. The inventors of this disclosure have found that spline 216A5 exhibits an overall stiffness reduction of about 9.41% compared to spline 216A1 under axial or radial compression.

[0084] Finally, the spline 216A6 provided for further consideration of the aforementioned reduction in stiffness has a uniform width along its entire length (i.e., no scalloped regions). The inventors of this disclosure have found that the spline 216A6 exhibits an overall reduction in stiffness of approximately 26.38% compared to the spline 216A1 under axial or radial compression.

[0085] The structural / mechanical properties of the electrode assembly 210 can be additionally or alternatively tuned through the techniques employed in its construction and formation. Figure 2G is a partial plan view illustrating the layout of the electrode assembly 210 in two dimensions, similar to that shown in Figure 2C, except as described below, while Figures 2H and 2I are schematic cross-sectional views of portions of the electrode assembly 210 obtained along the lines 2H-2H and 2I-2I, respectively. For convenience of explanation, details of the flexible circuit structure are omitted in Figures 2H and 2I.

[0086] The embodiment in Figure 2G differs from the embodiment illustrated in Figure 2C in that the electrode assembly 210 in Figure 2G includes a non-adhesive region 292 (the region depicted within the dashed circle in Figure 2G), and the flex circuit hub 230 and the portions of the flex circuit splines 234A-234F located within region 292 are not directly bonded to the lower support member 220. Accordingly, as shown in Figure 2H, in the region outside the non-adhesive region 292, the flexible circuit includes an adhesive layer 298 interposed between the flex circuit branch 234A and the support member branch 226A, joining them together. In contrast, within the non-adhesive region 292, there is no adhesive layer between the flex circuit spline 234A and the support member branch 226A. In the embodiment, the position of the boundary defining region 292 may be selected based on specific desired structural characteristics of the electrode assembly. In some embodiments, the boundary of region 292 may be located near the equator (i.e., equidistant from the proximal and distal ends) or at the maximum diameter position of the expanded electrode assembly 210 (see Figure 2A), while in other embodiments, the boundary may be located at a different position. The omission of direct mechanical attachment of the flexible circuit 222 to the support member 220 within region 292 allows for some relative motion between the support member 220 and the flexible circuit 222 within that region, thereby minimizing the stress transmitted to the flexible circuit 222 under external axial or radial compressive loads. Thus, this design reduces the strain applied to the flexible circuit 222 when the electrode assembly 210 is inserted into and withdrawn from a relatively small bore delivery sheath, and consequently reduces the plastic deformation of the flexible circuit 222 during use. The inclusion of region 292 tends to further reduce the overall rigidity of the expanded electrode assembly 210, thereby improving the degree to which the electrode assembly 210 can elastically deform and follow the target tissue (e.g., the endocardial wall) during pulsed-field ablation and associated mapping procedures.

[0087] Figures 4A and 4B illustrate the functionality of the catheter 200, particularly the electrode assembly 210, used in cardiac procedures. As seen in Figure 4A, the electrode assembly 210 can be positioned within the ventricle of interest, for example, the left atrium 410. When positioned within the blood pool of the left atrium 410, the electrode assembly 210 is pre-configured to assume a fully expanded shape. As shown in Figure 4B, the design of the electrode assembly 210 allows the spline 216 to elastically deform when the electrode assembly 210 is biased to contact the ventricular wall 420. The illustrated deformation results in maximizing the surface area of ​​the ablation electrode 238 (and sensing electrode 250) in contact with the target tissue without applying unnecessary force to the heart wall 420. The flexibility of the electrode assembly 210 further allows it to assume an undeformed expanded shape when retracted away from the heart wall 420.

[0088] Where a method involves one or more steps, it should be fully understood that the order in which they are described does not imply any limitation of the claims, unless otherwise explicitly or implicitly stated in this specification or the claims themselves. It should also be fully recognized that the illustrated methods are only a few examples of the many disclosed, and that certain steps may be added or omitted without departing from the scope of this disclosure. Such steps may include incorporating apparatus, systems, or methods, or components thereof, as well as matters that are well understood, commonplace, and customary in the art.

[0089] The connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical connections between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in actual systems. However, any benefits, effects, solutions to problems, and any elements that may produce or make more prominent any benefits, effects, or solutions should not be construed as important, necessary, or essential features or elements. Accordingly, the scope of this disclosure should not be limited by anything other than the appended claims, and references to singular elements are not intended to mean "one and only one," but rather "one or more," unless expressly stated otherwise. Furthermore, wherever phrases similar to "at least one of A, B, or C" are used in the claims, it is intended that these phrases mean that only A may exist in one embodiment, only B may exist in one embodiment, only C may exist in one embodiment, or that any combination of elements A, B, or C (e.g., A and B, A and C, B and C, or A and B and C) may exist in a single embodiment.

[0090] In the detailed description herein, references such as “one embodiment,” “a certain embodiment,” and “exemplary embodiment” indicate that the embodiments described may include certain features, structures, or characteristics, but not all embodiments necessarily include those specific features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, where certain features, structures, or characteristics are described in relation to one embodiment, whether explicitly stated or not, it is considered within the knowledge of a person skilled in the art who is interested in this disclosure that such features, structures, or characteristics will have an effect in relation to other embodiments. By reading the description, it will be clear to a person skilled in the art how to implement this disclosure in alternative embodiments.

[0091] Furthermore, no element, component, or method step in this disclosure is intended to be attributed to the public, whether or not that element, component, or method step is expressly described in the claims. The elements of the claims of this application should not be construed under 35 U.S.C. 112(f) unless that element is expressly described using the phrase “means for…”. Where used herein, the terms “comprises,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus containing a list of elements may include other elements that are not expressly enumerated or are not specific to such process, method, article, or apparatus, rather than containing only those elements.

[0092] Various modifications and additions can be made to the exemplary embodiments described without departing from the scope of this disclosure. For example, while the embodiments described above refer to specific features, the scope of this disclosure also includes embodiments having different combinations of features, and embodiments that do not include all of the described features. Accordingly, the scope of this disclosure is intended to encompass all such alternative forms, modifications, and variations included in the claims, along with all their equivalents.

Claims

1. A catheter for ablating cardiac tissue by irreversible electroporation, A tubular outer shaft having a proximal end and a distal end on the opposite side, An electrode assembly extending distally from the distal end of the outer shaft, wherein the electrode assembly defines a distally positioned central hub portion and a plurality of splines, each of which includes a distal end portion extending proximal to the central hub portion, a proximal end portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal end portion and the distal end portion, the electrode assembly comprising a flexible circuit hub and a plurality of splines integrally formed with the flexible circuit hub and extending proximal to the flexible circuit hub A catheter comprising: a flexible circuit having a flex circuit branch, the flexible circuit further including an outward-facing ablation electrode, the ablation electrode including an ablation electrode hub portion disposed on the flex circuit hub, and a plurality of ablation electrode branches integrally formed with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal along a corresponding portion of the plurality of flex circuit branches and terminating at the proximal end of the ablation electrode, the electrode assembly.

2. The catheter according to claim 1, wherein the flexible circuit further includes a plurality of spline sensing electrodes arranged on each flex circuit branch.

3. The catheter according to claim 2, wherein one or more of the plurality of spline detection electrodes on each flex circuit branch are positioned within the surface of the ablation electrode branch on each flex circuit branch and are electrically insulated from the ablation electrode.

4. The catheter according to claim 2 or 3, wherein one or more of the plurality of spline detection electrodes are positioned proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

5. The catheter according to any one of claims 1 to 4, wherein the proximal end of each ablation electrode branch has a curved shape.

6. The catheter according to any one of claims 1 to 5, wherein the distal end portion of each spline has a maximum distal width, and the intermediate portion of each spline has a maximum intermediate width that is greater than the maximum distal width.

7. The catheter according to claim 6, wherein the intermediate portion of each spline includes one or more scalloped regions, and each scalloped region has a scalloped region width smaller than the maximum width of the intermediate portion.

8. The catheter according to claim 7, wherein at least one scalloped region is located in a portion of each spline where a corresponding ablation electrode branch is positioned.

9. The catheter according to any one of claims 1 to 8, wherein each ablation electrode branch includes one or more ablation electrode branch openings, and one of the plurality of spline detection electrodes is positioned in a corresponding one of the proximal ablation electrode branch openings.

10. The catheter according to claim 9, wherein each ablation electrode branch opening is defined by the corresponding inner surface of the ablation electrode branch, and the outer surface of the spline detection electrode positioned within the corresponding ablation electrode branch opening is spaced apart from the corresponding inner surface of the ablation electrode branch.

11. The catheter according to any one of claims 1 to 10, wherein the flexible circuit further includes a hub sensing electrode positioned in the center of the flexible circuit hub.

12. The catheter according to any one of claims 1 to 11, further comprising one or more shaft electrodes positioned in close proximity to the distal end of the tubular outer shaft.

13. The catheter according to claim 12, wherein the ablation electrode and the one or more shaft electrodes are configured to form an anode / cathode electrode pair for delivering electroporation ablation energy to a target tissue.

14. The catheter according to any one of claims 1 to 13, wherein the electrode assembly further includes a support member, the support member having a support member hub and a plurality of support member branches extending proximal to the support member hub, the flex circuit hub is positioned on the support member hub, and each of the plurality of flex circuit branches is positioned on one of the plurality of support member branches.

15. The catheter according to claim 15, wherein the electrode assembly includes a first region disposed between the flexible circuit and the support member and including an adhesive layer for 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 to each other.

16. A catheter for ablating cardiac tissue by irreversible electroporation, A tubular outer shaft having a proximal end and a distal end on the opposite side, The electrode assembly comprises an electrode assembly extending distally from the distal end of the outer shaft, wherein the electrode assembly defines a distally positioned central hub portion and a plurality of splines, each of which includes a distal end portion extending proximal from the central hub portion, a proximal end portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal end portion and the distal end portion, and the electrode assembly comprises A support member having a support member hub and a plurality of support member branches extending proximal to the support member hub, A catheter comprising: a flexible circuit having a flex circuit hub disposed on the outer surface of the support member and disposed on the support member hub, and a plurality of flex circuit branches, each of the plurality of flex circuit branches disposed on one of the plurality of support member branches, and the flexible circuit further comprising an ablation electrode including an ablation electrode hub portion disposed on the flex circuit hub and a plurality of ablation electrode branches formed integrally with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal along one of the plurality of flex circuit branches and terminating at the proximal end of the ablation electrode.

17. The catheter according to claim 16, wherein the flexible circuit further includes a plurality of spline sensing electrodes arranged on each flexible circuit branch, one or more of the plurality of spline sensing electrodes on each flexible circuit branch are located within the surface of a corresponding ablation electrode branch arranged on the flexible circuit branch and are electrically insulated from the ablation electrode.

18. The catheter according to claim 17, wherein the proximal end of each ablation electrode branch has a curved shape.

19. The catheter according to claim 17, wherein one or more of the plurality of spline detection electrodes are positioned proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

20. The catheter according to claim 17, wherein each ablation electrode branch includes one or more ablation electrode branch openings, and one of the plurality of spline detection electrodes is positioned within one of the corresponding ablation electrode branch openings.

21. The catheter according to claim 20, wherein each ablation electrode branch opening is defined by the corresponding inner surface of the ablation electrode branch, and the outer surface of the spline detection electrode positioned within the corresponding ablation electrode branch opening is spaced apart from the corresponding inner surface of the ablation electrode branch.

22. The catheter according to claim 17, wherein the distal end portion of each spline has a maximum distal width, and the intermediate portion of each spline has a maximum intermediate width that is greater than the maximum distal width.

23. The catheter according to claim 22, wherein the intermediate portion of each spline includes one or more scalloped regions, each scalloped region having a scalloped region width smaller than the maximum width of the intermediate portion, and at least one scalloped region is located in a portion of each spline where a corresponding ablation electrode branch is located.

24. The catheter according to claim 17, wherein the flexible circuit further includes a hub sensing electrode positioned in the center of the flex circuit hub.

25. The catheter according to claim 17, further comprising one or more shaft electrodes positioned close to the distal end of the tubular outer shaft.

26. The catheter according to claim 25, wherein the ablation electrode and the one or more shaft electrodes are configured to form an anode / cathode electrode pair for delivering electroporation ablation energy to a target tissue.

27. A catheter for ablating cardiac tissue by irreversible electroporation, A tubular outer shaft having a proximal end and a distal end on the opposite side, The electrode assembly comprises an electrode assembly extending distally from the distal end of the outer shaft, wherein the electrode assembly defines a distally positioned central hub portion and a plurality of splines, each of which includes a distal end portion extending proximal from the central hub portion, a proximal end portion attached to and constrained by the outer shaft, and an intermediate portion between the proximal end portion and the distal end portion, and the electrode assembly comprises A support member formed from a superelastic material, comprising a support member hub and a plurality of support member branches integrally formed with the support member hub and extending proximal to the support member hub, A flexible circuit disposed on the outer surface of the support member, the flexible circuit having a flex circuit hub disposed on the support member hub and a plurality of flex circuit branches integrally formed with the flex circuit hub, each of the plurality of flex circuit branches being disposed on one of the plurality of support member branches, the flexible circuit is, An ablation electrode comprising an ablation electrode hub portion disposed on the flex circuit hub and a plurality of ablation electrode branches integrally formed with the ablation electrode hub portion, wherein each of the plurality of ablation electrode branches extends proximal to a corresponding portion of the plurality of flex circuit branches, A catheter comprising a flexible circuit including a plurality of spline sensing electrodes, wherein one or more of the plurality of spline sensing electrodes are positioned within the surface of each of the plurality of ablation electrode branches and are electrically insulated from the ablation electrodes.

28. The catheter according to claim 27, wherein the distal end portion of each spline has a maximum distal width, and the intermediate portion of each spline has a maximum intermediate width that is greater than the maximum distal width.

29. The catheter according to claim 28, wherein the intermediate portion of each spline includes one or more scalloped regions, each scalloped region having a scalloped region width smaller than the maximum width of the intermediate portion, and at least one scalloped region is located in a portion of each spline where a corresponding ablation electrode branch is located.

30. The catheter according to claim 29, wherein one or more of the plurality of spline detection electrodes are positioned proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

31. The catheter according to claim 30, wherein the flexible circuit further includes a hub sensing electrode positioned in the center of the flex circuit hub.

32. A catheter for ablating cardiac tissue by irreversible electroporation, A tubular outer shaft having a proximal end and a distal end on the opposite side, A catheter comprising: an electrode assembly extending distally from the distal end of the outer shaft, the electrode assembly comprising a flexible circuit having a central flex circuit hub located distally and a plurality of flex circuit branches extending proximal from the hub portion, each of the plurality of flex circuit branches comprising a proximal end portion that at least partially forms an electrode assembly spline and is attached to and constrained by the outer shaft, the flexible circuit further comprising an ablation electrode, the ablation electrode comprising an ablation electrode hub portion located on the flex circuit hub and a plurality of ablation electrode branches integrally formed with the ablation electrode hub portion, each of the plurality of ablation electrode branches extending proximal along a corresponding portion of the plurality of flex circuit branches and terminating at the proximal end, the electrode assembly.

33. The catheter according to claim 32, wherein the flexible circuit further includes a plurality of spline sensing electrodes arranged on each flex circuit branch, one or more of the plurality of spline sensing electrodes on each flex circuit branch are arranged within the surface of the corresponding ablation electrode branch on the flex circuit branch and are electrically insulated from the ablation electrode.

34. The catheter according to claim 33, wherein one or more of the plurality of spline detection electrodes are positioned proximal to the proximal end of the ablation electrode branch on each flex circuit branch.

35. The catheter according to claim 34, wherein the flexible circuit further includes a hub sensing electrode positioned in the center of the flex circuit hub.

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