Wide area focused ablation catheter with insulating portion

Abstract

An electroporation catheter for ablating cardiac tissue is disclosed. The electroporation catheter includes an elongate shaft having a proximal end and an opposite distal end. The elongate shaft defines an axis. The electrode assembly is coupled to and extends distally from the distal end of the elongate shaft. The electrode assembly is transitionable between a contracted state and an expanded state. The electrode assembly includes an electrically conductive strut defining a spherical shape in an expanded state, having a proximal portion coupled to the elongate shaft, a central portion having a maximum radial dimension, and a distal portion opposite the elongate shaft. A proximal insulating portion is disposed on the proximal portion of the electrode assembly surrounding each of the plurality of conductive struts. The proximal insulator portion extends from the proximal end to at least the central portion.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 578,585, filed August 24, 2023, entitled “WIDE-AREA FOCAL ABLATION CATHETERHAVING INSULATED PORTIONS”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to medical systems and methods for facilitating tissue ablation in a patient. More specifically, this disclosure relates to medical systems and methods for facilitating tissue ablation 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, cancerous tumors, and to control bleeding during surgery. 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 transmitted 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 cold, heat-conducting fluid circulates through the probe to freeze and kill the surrounding tissue. Both RF ablation and cryoablation techniques can indiscriminately kill tissue through cell necrosis, which may damage or otherwise kill 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 cells to increase the permeability of the cell membrane. Electroporation can be reversible or irreversible, depending on the strength and duration of the electric field. If electroporation is reversible, the temporary increase in cell membrane permeability can be used to introduce chemicals, drugs, or DNA into the cells before they heal and recover. Tissue recovery can occur minutes, hours, or days after the ablation is complete. If electroporation is irreversible, the affected cells are killed, for example, through forms of cell death, such as programmed cell death, such as apoptosis, or traumatic cell death, such as necrosis.

[0006] Irreversible electroporation can be used as a non-thermal ablation technique. In irreversible electroporation, a series of short, high-voltage pulses are used to generate an electric field strong enough to kill cells. In the ablation of cardiac tissue, irreversible electroporation may be a relatively safe and effective alternative to the indiscriminate killing of cells by thermal ablation techniques such as RF ablation and cryoablation. By using selected electric field strength and duration, irreversible electroporation can be used to kill target tissue (such as myocardial tissue) effectively, but ineffective in permanently damaging other cells or tissues (such as non-target myocardial tissue, erythrocytes, vascular smooth muscle tissue, endothelial tissue, and nerve cells). Summary of the Invention

[0007] In Example 1, an electroporation catheter for ablating cardiac tissue is provided. The electroporation catheter includes: an elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis; an electrode assembly coupled to and extending distally from the distal end of the elongated shaft, the electrode assembly being switchable between a contracted state and an expanded state, wherein the electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposing the elongated shaft; and a proximal insulating portion disposed on the proximal portion of the electrode assembly, surrounding each of the plurality of conductive struts, the proximal insulating portion extending from the proximal end to at least the central portion.

[0008] In Example 2, according to the electroporation catheter of Example 1, the ablation electrode in the expanded state includes a maximum radial dimension larger than the maximum radial dimension of the distal region of the elongated axis.

[0009] In Example 3, the electroporation catheter according to Example 2 is provided, wherein the maximum radial dimension of the ablation electrode defines the equator on the electrode assembly.

[0010] In Example 4, the electroporation conduit according to Example 3 is provided with a proximal insulating portion on a conductive post extending from the proximal end to the equator.

[0011] In Example 5, according to the electroporation conduit of Example 3, a proximal insulator is disposed on a conductive strut from the proximal end to a chord located on the electrode assembly on the far side of the equator.

[0012] In Example 6, the electroporation conduit according to any one of Examples 1-5, wherein the conductive struts form a mesh shell.

[0013] In Example 7, the electroporation conduit according to Example 6 is provided, wherein the conductive struts are arranged in multiple units on the grid shell.

[0014] In Example 8, the electroporation conduit according to any one of Examples 1-5, wherein the conductive struts form a plurality of longitudinally extending support strips to form a basket-like outer shell.

[0015] In Example 9, the electroporation conduit according to any one of Examples 1-8 further includes an axial electrode disposed on the distal region of the axial shaft.

[0016] In Example 10, according to the electroporation conduit of Example 9, the electrode assembly and the axial electrode are configured as either a cathode or an anode to generate an electric field in unipolar mode.

[0017] In Example 11, according to the electroporation conduit of Example 9, the electrode assembly is configured as one of a cathode and an anode, and the axial electrode is configured as the other of an anode and a cathode to generate an electric field in bipolar mode.

[0018] In Example 12, the electroporation catheter according to any one of Examples 1-11 further includes a plurality of sensing electrodes disposed on the electrode assembly.

[0019] In Example 13, according to the electroporation conduit of Example 12, the electrode assembly includes a plurality of electrodes configured as either a cathode or an anode to generate an electric field in unipolar mode.

[0020] In Example 14, the electroporation conduit according to any one of Examples 1-13 further includes a second insulator selectively disposed on the conductive post, located distal to the proximal insulating portion.

[0021] In Example 15, the electroporation conduit according to Example 14, wherein a second insulator is disposed on the inner surface of one of the plurality of conductive struts, the inner surface facing the internal cavity of the electrode assembly, and the outer surface of the strut among the plurality of conductive struts is exposed.

[0022] In Example 16, an electroporation catheter for ablating cardiac tissue is provided. The electroporation catheter includes: an elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis; an electrode assembly coupled to and extending distally from the distal end of the elongated shaft, the electrode assembly being switchable between a contracted state and an expanded state, wherein the electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposing the elongated shaft; and a proximal insulating portion disposed on the proximal portion of the electrode assembly, surrounding each of the plurality of conductive struts, the proximal insulating portion extending from the proximal end to at least the central portion.

[0023] In Example 17, the electroporation catheter according to Example 16 is provided, wherein the ablation electrode in the expanded state includes a maximum radial dimension larger than the maximum radial dimension of the distal region of the elongated axis.

[0024] In Example 18, according to the electroporation catheter of Example 17, the maximum radial dimension of the ablation electrode defines the equator on the electrode assembly.

[0025] In Example 19, the electroporation conduit according to Example 18 is provided with a proximal insulating portion on a conductive post extending from the proximal end to the equator.

[0026] In Example 20, according to the electroporation conduit of Example 18, a proximal insulator is disposed on a conductive strut from the proximal end to a chord located on the electrode assembly on the far side of the equator.

[0027] In Example 21, the electroporation conduit according to Example 16 is provided, wherein the conductive struts form a mesh shell.

[0028] In Example 22, the electroporation conduit according to Example 21 is provided, wherein the conductive struts are arranged in multiple units on the grid shell.

[0029] In Example 23, the electroporation conduit according to Example 16 is provided, wherein the conductive struts include a plurality of longitudinally extending support strips to form a basket-like outer shell.

[0030] In Example 24, the electroporation conduit according to Example 16 further includes an axial electrode disposed on the distal region of the axial shaft.

[0031] In Example 25, the electroporation conduit according to Example 24 is provided, wherein the electrode assembly and the axial electrode are configured as either a cathode or an anode to generate an electric field in unipolar mode.

[0032] In Example 26, according to the electroporation conduit of Example 24, the electrode assembly is configured as one of a cathode and an anode, and the axial electrode is configured as the other of an anode and a cathode to generate an electric field in bipolar mode.

[0033] In Example 27, the electroporation conduit according to Example 16 further includes a plurality of sensing electrodes disposed on the electrode assembly.

[0034] In Example 28, according to the electroporation conduit of Example 27, the electrode assembly includes a plurality of electrodes configured as either a cathode or an anode to generate an electric field in unipolar mode.

[0035] In Example 29, the electroporation conduit according to Example 16 further includes a second insulator selectively disposed on the conductive post, located distal to the proximal insulating portion.

[0036] In Example 30, the electroporation conduit according to Example 29, wherein a second insulator is disposed on the inner surface of one of the plurality of conductive struts, the inner surface facing the internal cavity of the electrode assembly, and the outer surface of the strut among the plurality of conductive struts is exposed.

[0037] In Example 31, an electrophysiological system includes an electroporation console configured to generate pulsed electrical signals for electroporation ablation and an electroporation catheter coupled to the electroporation console. The electroporation catheter includes: an elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis; an electrode assembly coupled to and extending distally from the distal end of the elongated shaft, the electrode assembly being switchable between a contracted state and an expanded state, wherein the electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposing the elongated shaft; and a proximal insulating portion disposed on the proximal portion of the electrode assembly, surrounding each of the plurality of conductive struts, the proximal insulating portion extending from the proximal end to at least the central portion.

[0038] In Example 32, the electroporation catheter according to Example 31 is configured to operate in both bipolar and unipolar modes.

[0039] In Example 33, an electroporation catheter for ablating cardiac tissue is provided. The electroporation catheter includes: an elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis and including an axial electrode disposed at the distal end; an electrode assembly coupled to and extending distally from the distal end of the elongated shaft, the electrode assembly being switchable between a contracted state and an expanded state, wherein the electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposing the elongated shaft, the electrode assembly being operable in a bipolar mode and a unipolar mode; and a proximal insulating portion disposed on the proximal portion of the electrode assembly, surrounding each of the plurality of conductive struts, the proximal insulating portion extending from the proximal end to at least the central portion. The electrode assembly and the axial electrode are configured as either a cathode or an anode to generate an electric field in unipolar mode. The electrode assembly is configured as one of the cathode and the anode, and the axial electrode is configured as the other of the anode and the cathode to generate an electric field in bipolar mode.

[0040] In Example 34, according to the electroporation catheter of Example 33, the ablation electrode in the expanded state includes a maximum radial dimension larger than the maximum radial dimension of the distal region of the elongated shaft, and wherein a proximal insulator is disposed on the conductive strut from the proximal end to a chord located distal to the maximum radial dimension on the electrode assembly.

[0041] In Example 35, the electroporation conduit according to Example 33 is provided, wherein the conductive struts form one of a mesh shell and a basket-shaped shell.

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

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

[0044] Figure 2 It shows that it can be used with Figure 1 A schematic diagram of the distal portion of an example catheter used in conjunction with an example electrophysiological system.

[0045] Figures 3A-3B It shows that according to Figure 2 Example of a catheter, the example distal portion of the catheter.

[0046] Figures 4A-4B It shows that according to Figure 2 Example of a catheter, the example distal portion of the catheter.

[0047] Figure 5A and Figure 5B It shows via Figure 2 Example electric field generated by an example conduit.

[0048] While various modifications and alternatives may be made to the invention, specific embodiments are shown by way of example in the accompanying drawings and are described in detail below. However, the invention is not intended to be limited to the specific embodiments described. Rather, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. Detailed Implementation

[0049] To facilitate understanding of the principles of this disclosure, reference is now made to the examples illustrated 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 were chosen and described to enable others skilled in the art to use their teachings. The use of multiple (e.g., all) features in one example across all examples does not exceed the scope of this disclosure. Therefore, no single figure should be construed as having any dependence on or requirement for any individual component or combination of components shown herein. Furthermore, in the examples, various components depicted in the drawings may be integrated with various components in other components depicted therein (or components not shown), all of which are considered to be within the scope of this disclosure.

[0050] When applied to electrophysiological systems, irreversible electroporation uses high voltage, short pulses to kill cells (such as myocardium) through apoptosis without harming other adjacent tissues, including esophageal vascular smooth muscle and endothelium. Irreversible electroporation can be delivered in multiple treatment segments. Treatment segments lasting in the millisecond range can include multiple electrical pulses, such as dozens of pulses, generated and delivered by an electroporation device powered by an electroporation generator to produce an electric field of sufficient strength to create transmural damage. Such pulsed field ablation generates a roughly spherical electric field around a roughly point electrode, or a field with a roughly circular cross-section around a roughly linear electrode, which is generally independent of the tissue or blood in the heart. Such fields may include the possibility of collateral damage to adjacent areas located on the blood pool side of the electrode or on the side opposite the target tissue. In contrast, RF ablation can be concentrated on the area in direct contact with the electrode.

[0051] Electroporation devices used for ablation and cardiac mapping (such as mapping and ablation catheters) are generally larger in size than many RF ablation catheters. For example, the working tip diameter of a mapping and ablation catheter can be 7 mm to 15 mm or larger. Such catheters typically generate a relatively large electric field for ablation, which increases the likelihood of collateral damage to areas opposite the target myocardial tissue.

[0052] Figure 1An example clinical setup 10 is shown for treating a patient 20 (e.g., treating the heart 30 of patient 20) using an electrophysiology system 50 according to this disclosure. The electrophysiology system 50 includes an electroporation catheter system 60 and an electroanatomical mapping (EAM) system 70. The example electroporation catheter system 60 includes an electroporation catheter 105, a guide sheath 110, and an electroporation console 130. Additionally, the electroporation catheter system 60 includes various connecting elements (e.g., cables) operatively connecting components of the electroporation catheter system 60 to each other and to components of the EAM system 70. Generally, the EAM mapping system 70 includes a positioning field generator 80, a mapping and navigation controller 90, and a display 92. Furthermore, the clinical setup 10 may include additional equipment (e.g., an imaging device 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 electrophysiology system 50. The clinical setup 10 may have… Figure 1 Other components and their arrangement not shown.

[0053] The electroporation catheter system 60 is configured to deliver ablation electric field energy to target tissue within the patient's heart 30 to induce cell death in the tissue, for example, to prevent the tissue from conducting electrical signals. Furthermore, the electroporation catheter system 60 is configured to use the electroporation catheter 105 to generate an electric field to form and display an electroanatomical mapping of the patient's heart on a display 92, thereby assisting clinicians in planning ablation via irreversible electroporation using the electroporation catheter 105 prior to delivering the ablation electric field energy. In an embodiment, the electroporation catheter system 60 is configured to generate the electric field based on the characteristics of the electroporation catheter 105 and its location within the patient 20 (e.g., within the patient's heart 30). The electroporation catheter system 60 is configured to generate electroanatomical mapping and a graphical representation of the electroporation catheter 105 based on the characteristics of the electroporation catheter 105 and its location within the patient 20 (e.g., within the patient 20's heart 30), as well as the characteristics of the tissue surrounding the catheter 105 (e.g., measured tissue impedance). In one example, the electroporation catheter 105 is a mapping and ablation catheter that can cooperate with the EAM system 70 to be deployed in a mapping procedure and to deliver ablation electric field energy and ablate tissue via irreversible electroporation.

[0054] The guide sheath 110 is operable to provide a delivery conduit through which the electroporation catheter 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 the blood vessel is established, the electroporation catheter 105 can be navigated into the patient's heart, such as into a ventricle.

[0055] Example electroporation catheter 105 includes an elongated catheter shaft and a distal end region configured for deployment near a target tissue, such as within a chamber of a patient's heart. The shaft extends from an entry point within the patient to the target tissue and typically defines the longitudinal axis of the electroporation catheter 105. The distal end region may include a basket, balloon, support strip, configured tip, or other electrode deployment mechanism coupled to the shaft. The electrode deployment mechanism includes an electrode assembly or array containing electrodes. For example, the electrode assembly may include a plurality of spaced-apart electrodes or multiple sets or groups of spaced-apart electrodes. In some examples, electrodes, such as a plurality of spaced-apart electrodes, may be deployed on the catheter shaft in addition to or in place of the electrodes on the electrode deployment mechanism. For example, the electrode deployment mechanism includes a plurality of support strips configured to form a basket, and at least some of the electrodes are disposed on the support strips.

[0056] The electroporation catheter 105 can be configured in a variety of ways. For example, when the distal end region of the catheter 105 is within the sheath as a catheter assembly, such as when it is traveling into a patient's body or into a heart chamber, the electrode deployment mechanism and electrode assembly are in a retracted state to fit within the sheath. For example, once the catheter has reached its destination in the heart chamber, the sheath retracts from the distal region of the catheter 105 (or the axial catheter extends beyond the sheath), and the electrode deployment mechanism and electrode assembly can be arranged in an expanded state. When the catheter 105 is in the retracted state, the electrode assembly has a retracted shape, and when the catheter 105 is in the expanded state, the electrode assembly has an expanded shape. In some examples, the electrode assembly has more than two states.

[0057] In one example, multiple electrodes may be formed of a conductive, solid-surface, biocompatible material and spaced apart on an insulator. Each of the multiple electrodes is electrically coupled to a corresponding elongated lead conductor that extends along the axis to the proximal end of the catheter. In one example, each of the spaced-apart electrodes corresponds to a single, individual lead conductor. In another example, multiple electrodes may be coupled to a single lead conductor. Other configurations are also considered. The multiple lead conductors may be insulated from each other within an insulating sheath along the catheter axis, such as using an insulating polymer sheath. The lead conductors may be electrically coupled to a plug located in the proximal region of the electroporation catheter 105, such as a plug configured to be mechanically and electrically coupled to the electroporation console 130 (e.g., directly or via an intermediate electrical conductor, such as a cable connection).

[0058] The electroporation console 130 includes a controller (such as one or more controllers, processors, or computers) that executes instructions or code (such as processor-executable instructions) from a non-transitory computer-readable medium (such as a memory device or memory) to cause (such as control or execute) aspects of the electroporation catheter system 60. In one example, the electroporation console 130 is configured to provide electrical signals (such as multiple electrical signals simultaneously or spaced apart in time) to an electrically connected electroporation catheter 105 along lead conductors leading to spaced-apart electrodes. The spaced-apart electrodes are configured to generate a selected electric field near the target tissue based on the electrical signals from the electroporation console 130, thereby achieving ablation.

[0059] The electroporation control console 130 can generate electrical signals and select which electrodes in the electrode array will receive those signals. A first electrode or a first group of electrodes can be selected as the anode, while different second electrodes or a second group of electrodes can be selected as the cathode, allowing an electric field to be generated between the anode and cathode based on signals (such as pulses) supplied to the electrodes from the electroporation control console 130. The control console 130 supplies electrical pulses of varying lengths and amplitudes to the electrodes on the conduit 105. The electrical pulses can be provided as a continuous stream of pulses or as multiple separate pulse trains. Pulse parameters of interest include the number of pulses, the duty cycle of the pulses, the interval between pulse trains, the voltage or amplitude of the pulses (including peak voltage), and the duration of the voltage. For example, the control console 130 can select two or more electrodes in the electrode assembly and supply pulses to the selected electrodes to generate an electric field between them.

[0060] In ablation mode, the console can select electrodes to provide pulsed field ablation (PFA). For example, PFA can be performed using monophasic and biphasic waveforms. Without being bound by any specific theory, electric field strengths with microsecond-level pulse durations in the range of approximately 200–250 volts (V / cm) have been shown to provide reversible electroporation in cardiac tissue. Electric field strengths of approximately 400 V / cm have been shown to provide irreversible electroporation in cardiac tissues of interest, such as target myocardial and endocardial tissues, without damaging red blood cells, vascular smooth muscle tissue, endothelial tissue, nerve tissue, and other non-target-adjacent tissues.

[0061] Additionally, the electrode assembly on catheter 105 can operate in selected modes, such as unipolar or bipolar modes. During unipolar operation of catheter 105, an electrode, a group of electrodes, or the entire electrode assembly is configured as either an anode or a cathode. No electrode in the electrode assembly is configured as either a cathode or an anode. Instead, the other of the cathode or anode is provided as a pad-dispersed electrode located on the patient, typically in the back, buttocks, or other suitable anatomical position during electroporation. An electric field is formed between the activating electrode and the pad-dispersed electrode of the electrode assembly. In an alternative configuration, return electrodes (e.g., multiple return electrodes) may be positioned on the axis of the catheter. An electric field is formed between the activating electrode of the electrode assembly and the return electrode located on the axis of catheter 105. During bipolar operation of catheter 105, one or more electrodes from a first group of the electrode assembly are configured as anodes, while one or more electrodes from a second group of the electrode assembly are configured as cathodes to generate an electric field. In this example, a pad-dispersed electrode is not used, and the electric field does not extend within the patient's body but rather through a localized portion of the tissue near the electrode assembly.

[0062] In some embodiments, the catheter may include sensing electrodes to receive electrical signals from target tissue, rather than delivering them. For example, catheter 105 may be a mapping and ablation catheter, and the electrodes may include an ablation electrode configured to deliver ablation electric field energy and a mapping electrode or sensing electrode for mapping purposes. In some configurations, the mapping electrode is configured to collect electrical signals (for generation via an operably coupled EAM system 70) and display detailed three-dimensional geometric anatomical mappings or representations of cardiac chambers and electroanatomical mappings via an operably coupled display 92, wherein the cardiac electrical activity of interest is superimposed on the geometric anatomical mappings. In some examples, the electrode may operate as an ablation electrode in the ablation mode of the electrophysiology system 50 and as a mapping electrode in the mapping mode of the system 50. The mapping electrode on the electroporation catheter 105 may measure electrical signals and generate an output signal that may be processed by the mapping and navigation controller 90 to generate an electroanatomical mapping. In some cases, the electroanatomical mapping is generated prior to ablation to determine the electrical activity of cardiac tissue within the chamber of interest. In some cases, electroanatomical mapping is generated after ablation to verify desired changes in the electrical activity of the chamber and the ablated tissue. Mapping electrodes can also be used to determine the location of catheter 105 in three-dimensional space within the body. For example, as an operator moves the distal end of catheter 105 within a cardiac chamber of interest, mapping and navigation controller 90 can use the boundaries of catheter movement to create an anatomical mapping of the chamber. The chamber anatomical mapping can facilitate navigation of catheter 105 without the use of ionizing radiation (such as fluoroscopy) and can be used to mark the ablation site upon completion of ablation to guide ablation intervals and assist clinicians in ablating anatomical structures of interest. In some examples, electrodes in the electrode assembly can be configured to perform ablation only, or electrodes in the electrode assembly can be configured to perform mapping only. However, in some embodiments, in addition to ablation electrodes, sensing electrodes can be configured to deliver ablation energy.

[0063] EAM system 70 is configured to generate electroanatomical mappings for display on display 92. EAM system 70 is operable to track the location of various components of electroporation catheter system 60 and generate high-fidelity three-dimensional anatomical and electroanatomical mappings of the heart, including parts of the heart such as the chambers of interest or other structures of interest such as the sinoatrial node or atrioventricular node. In an illustrative example, EAM system 70 may include the RHYTHMIA™ HDx mapping system sold by Boston Scientific Corporation. Furthermore, mapping and navigation controller 90 of EAM system 70 includes one or more controllers (such as microprocessors or computers) that execute code from memory to control or perform functional aspects of EAM system 70, wherein the memory may be part of one or more controllers, microprocessors, computers, or a memory device accessible via a computer network.

[0064] The EAM system 70 generates a positioning field via a field generator 80 to define a positioning volume around the heart 30, and a position sensor or sensing element on the tracked device (such as a sensor on the electroporation catheter 105) generates an output that can be processed by the mapping and navigation controller 90 to track the sensor's position within the positioning volume, and thus track the corresponding device's position within the positioning volume. In the illustrated example, device tracking is achieved using magnetic tracking technology, where the field generator 80 is a magnetic field generator that generates a magnetic field defining the positioning volume, and the position sensor on the tracked device is a magnetic field sensor.

[0065] In other examples, impedance tracking methods can be used to track the position of various devices. In such examples, the positioning field is an electric field generated, for example, by an external field generator (such as surface electrodes), an in vivo or intracardiac device (such as an intracardiac catheter), or both. In these examples, position sensing elements can form electrodes on the tracked device, generating an output received and processed by the mapping and navigation controller 90 to track the position of various position sensing electrodes within the positioning volume.

[0066] The EAM system 70 can be configured for both magnetic and impedance tracking capabilities. In such examples, impedance tracking accuracy can be enhanced in some cases by first creating a mapping of the electric field induced by an electric field generator within the cardiac chamber of interest using a probe equipped with a magnetic position sensor, as may be possible using the RHYTHMIA HDx™ mapping system. An exemplary probe is the INTELLAMAP ORION™ mapping catheter, sold by Boston Scientific Corporation.

[0067] Regardless of the tracking method used, the EAM system 70 utilizes location information for various tracked devices and cardiac electrical activity acquired by, for example, the electroporation catheter 105 or another catheter or probe equipped with sensing electrodes to generate and display detailed three-dimensional geometric anatomical maps or representations of cardiac tissues and spaces (such as cardiac chambers) and electroanatomical maps via the display 92, where the cardiac electrical activity of interest is superimposed on the geometric anatomical maps. Furthermore, the EAM system 70 can generate graphical representations of various tracked devices within the geometric anatomical maps or electroanatomical maps.

[0068] The electroporation catheter system 60 can be combined with or integrated with the EAM system 70 to allow a graphical representation of the electric field that the electroporation catheter 105 can generate to be visualized on an electroanatomical mapping of the patient's heart. The integrated system may include the ability to enhance the efficiency of clinical workflows, including enhancing the visual representation of the ablation damage to portions of the patient's heart created by irreversible electroporation. The integrated system may include generating a graphical representation of the electric field that can be generated by the electroporation catheter 105, generating anatomical mapping (including generating electroanatomical mapping), and displaying information related to the location and intensity of the electric field that can be generated by the electroporation catheter 105.

[0069] Figure 1 The depiction of the electrophysiological system 50 shown is intended to illustrate or generally summarize the various components of the system 50 and is not intended to imply that this disclosure is limited to any set of components or arrangement of components. For example, the electrophysiological system 50 may include additional hardware components, such as adapter boxes or workstations.

[0070] Once a choice is made between pulmonary vein isolation and posterior wall isolation, catheters with wide-area focused ablation electrode assemblies (such as expandable electrode assemblies with an operating radial dimension typically larger than that of the catheter axis) can generate a larger lesion and coverage area on the target tissue than catheter axis electrodes, and provide more control and flexibility than single-shot electrode assemblies. Physicians prefer to work with wide-area focused ablation catheters if the lesion coverage area can be predicted. Furthermore, wide-area focused ablation electrode assemblies can typically operate in both unipolar and bipolar modes, which create different morphologies of lesions. However, in some examples, wide-area focused ablation electrode assemblies designed for both unipolar and bipolar operation are optimized for one mode or the other. For example, an electrode assembly may create a preferred broad omnidirectional electric field in unipolar mode, while there may be a risk of arcing in bipolar mode. This disclosure includes embodiments of catheters that address design considerations for both unipolar and bipolar operation.

[0071] Figure 2Features of an electroporation catheter 200 for ablation of cardiac tissue, or a distal region 205 of an electroporation catheter 200, are shown. This can be an example of catheter 105 and is used in conjunction with an electrophysiological system 50. The electroporation catheter 200 includes an elongated shaft 202 defining a longitudinal axis A and having a distal end 204 opposite to a proximal end. The longitudinal axis A is represented as a line passing through the centroid of a cross-section of the shaft 202. The distal region 205 of the catheter 200 is configured to be deployed near target tissue, such as within a chamber of a patient's heart. An expandable electrode assembly 210 is coupled to the distal end 204 of the shaft and configured to generate an electric field. In one example, the electric field creates irreversible electroporation in selected cardiac tissue. The electrode assembly 210 is switchable between a constricted state and an expanded state. In the expanded state, the electrode assembly 210 has a maximum radial dimension larger than the maximum radial dimension of the distal end 204 of the elongated shaft 202. Electrode assembly 210 includes a conductive housing 212 comprising a plurality of conductive struts 214. Embodiments of the conductive housing 212 and struts 214 can be formed in one of a variety of spherical configurations. As used herein to define the shape of the electrode assembly in its expanded state, a sphere includes a sphere, a spherical body (as an approximate spherical body), an ellipsoid, and other three-dimensional analogues of curved shapes with or without circular symmetry. Among these configurations is a mesh-like spherical housing formed by a grid of struts. Another of these configurations includes a basket-like housing formed by struts configured as longitudinally extending support bars. Other configurations are also contemplated. Housing 212 includes a proximal portion 220 including a proximal end 222 coupled to an elongated shaft 202. Housing 212 extends distally along axis A to a central portion 224 and a distal portion 226, the central portion comprising the largest radial dimension, and the distal portions converging at a distal end 228. Insulator 230 is disposed on at least the proximal portion 220 of housing 212 and surrounds the conductive struts 214. The insulator 230 extends continuously from the proximal end 222 to the middle portion 224.

[0072] In embodiments, the elongated shaft 202 is formed of a biocompatible material that provides sufficient rigidity and flexibility to allow the shaft 202 to be navigated through the patient's vascular system and to reach the treatment site (such as a chamber of the heart). In some embodiments, the shaft 202 is formed of a variety of different materials to configure the electroporation catheter 200 to have greater flexibility at the distal end 204 than at the proximal end. Furthermore, the shaft 202 may include tubular braided members to provide torsional stiffness and bending flexibility. The shaft 202 may include various markers (such as radiopaque or echo markers) for use with a visualization system, or include EAM electrodes for visualization purposes. The catheter shaft 202 may also house traction wires to deflect the electrode assembly 210 to the treatment site. The distal end 204 may include sensors (such as tracking sensors and force sensors) and additional elements (such as flushing elements). In some embodiments, a rod (not shown) extends from the elongated shaft into the housing 212 of the ablation electrode 210, and this rod is configured to include flushing elements, sensors, and other components. In some embodiments, the distal end 204 of the shaft 202 includes an exposed shaft electrode 208, such as a plurality of exposed shaft electrodes, located proximal to the electrode assembly 210. The exposed shaft electrode 208 in the embodiments may be used with the electrode assembly 210 and configured as a return electrode in bipolar mode, or configured as an additional active electrode of the electrode assembly 210 to function in the electric field described in the PFA vector in unipolar mode.

[0073] The electrode assembly 210 in this embodiment includes a conductive coupling portion 240 and a conductive deformable portion 242. The coupling portion 240 is fixed to the distal end 204 of the shaft 202, and the deformable portion 242 extends distally from the coupling portion 240. The deformable portion 242 can be contracted, for example, by a guide sheath, for delivery, and can be expanded for treatment at a treatment site. The coupling portion 240 is mechanically coupled directly or indirectly to the catheter shaft 202. The coupling portion 240 may include components directly coupled to the shaft 202 or coupled to a transition portion coupled to the shaft 202. The coupling portion 240 is electrically coupled to a conductive path (e.g., a wire) extending along the shaft 202 to the proximal end of the shaft. When used with the electrophysiological system 50, the electroporation console 130 is electrically coupled to the coupling portion 240 via the conductive path in the shaft 202. The deformable portion 242 includes a proximal portion 220 mechanically and electrically coupled to the coupling portion 240. In one embodiment, the deformable portion 242 defines an opening region through which blood or other fluids can flow. For example, the housing 212 forms a concave shape around the internal cavity C, and the configuration of the strut 214 provides an opening O in the housing 212. The housing provides a conductive structure that can be configured as a single ablation electrode with the system 50. The housing 212 receives electrical energy and is configured to generate an electric field to achieve irreversible electroporation in selected cardiac tissue. In one embodiment, the strut 214 is an axial element comprising a thin conductor to form the structure of the housing 212 and define the opening region. Examples of struts include flexible round wires, pins, metal strips, strips, flat wires, and wooden boards. In some embodiments, the housing 212 may be formed of a conductive shape memory material (such as a nickel-titanium alloy) that expands once the contractor device under applied axial force is removed, or of another conductive material that expands and contracts via a controllable mechanism. The deformable portion 242 includes a cross-sectional dimension larger than the cross-sectional dimension of the shaft 202, such as a dimension substantially perpendicular to axis A. Electrode assembly 210 can provide broader damage by electroporating tissue in a shorter time period to form a pattern of overlapping damage on the tissue, thereby reducing the likelihood of arrhythmia gaps, or the tip can be made easy to deliver more power to provide deeper damage than a catheter shaft electrode.

[0074] Insulator 230 is an electrical insulator that prevents electrical energy from being delivered to housing 212. Insulator 230 is disposed on at least the proximal portion 220 of housing 212 and surrounds conductive strut 214. For example, in this embodiment, insulator 230 extends entirely around the axial element of strut 214 and does not provide insulating radial gaps to expose the conductors of strut 214. Insulator 230 extends continuously from the proximal end 222 to the central portion 224. For example, insulator 230 does not include longitudinal gaps exposing the conductors of strut 214. In some embodiments, insulating portion 230 is constructed of a polymer applied to housing 212 (e.g., via dip coating or spray coating). In some embodiments, insulator 230 is a tubular polymer, such as a shrink-fit polymer disposed around strut 212 and attached in place. In some embodiments, insulator 230 is a metal oxide formed by a manufacturing process (e.g., physical vapor deposition or physical vapor transport (or vacuum deposition type), sputtering, or electrochemical process) to deposit a thin film or coating on strut 212. In addition to the proximal portion 220, the insulator may extend distally to the central portion 224, such as to the distal side of the maximum radial dimension of the housing 212.

[0075] In some embodiments, electrode assembly 210 includes one or more additional electrodes, such as sensing or mapping electrodes 248 in addition to the conductive housing 212. For example, multiple sensing electrodes 248 may be attached to housing 212 at selected locations (e.g., distal end 228) and electrically isolated from struts 214. In an example of a basket-shaped housing formed by multiple support bars, the sensing electrodes 248 may be spaced apart from each other on each support bar. An electrical insulator may be disposed between the sensing electrodes 248 and the associated struts 214. The sensing electrodes 248 are configured to sense cardiac electrical signals, such as locating electrode assembly 210 within a patient's anatomy via EAM system 70, and determining proximity to target tissue within the anatomy. The sensing electrodes 248 in electrode assembly 210 may be electrically coupled to one or more lead conductors along the length of extension shaft 202, the one or more lead conductors being configured to carry electrical signals received at mapping electrodes 248. However, in some embodiments, in addition to the housing 212, one or more of the sensing electrodes 248 may be configured together with the system 50 to deliver ablation energy.

[0076] In this embodiment, catheter 200 is configured to operate in a bipolar mode to generate an electric field for electroporation. During bipolar operation of catheter 200, housing 212 is configured as an anode (or cathode), while a second set of one or more electrodes (e.g., exposed axial electrode 208) located at the distal portion 205 of catheter 200 are configured as cathodes (or anodes) to generate the electric field. In this example, the aforementioned pad-dispersive electrodes are not used, and the electric field typically does not extend across the patient's body but rather through a localized portion of the tissue near electrode assembly 210.

[0077] With the entire housing 212 exposed and intended to create broad damage in the target tissue, the bipolar field vector is close to the return electrode of the axial electrode 208, and the conduit 200 is at risk of arcing and other performance degradation. Furthermore, the depth of damage in the target tissue depends on whether the exposed surface areas of the active and return electrodes are similar, or whether the surface area of ​​the tissue contacting the active electrode is smaller than that of the return electrode. A fully exposed housing 212 is not conducive to optimized bipolar operation. Instead of projecting electroporation energy radially and symmetrically in all directions from the spherical housing 212, an insulator 230 is provided on the housing. Therefore, the insulator 230 is provided on the housing, particularly at the proximal portion 220 and further distally, to reduce the likelihood of arcing and, as explained further, additional coverage.

[0078] In contrast to bipolar operation, a fully exposed housing 210 is acceptable for operation in unipolar mode. In embodiments, catheter 200 is also configured to operate in unipolar mode to generate an electric field for electroporation. For example, housing 212 may be electrically coupled to a single lead conductor extending the length of shaft 202, or electrically coupled to a set of lead conductors in shaft 202 configured to carry the same electrical signal to generate an electric field. Housing 212 is configured as either an anode or a cathode. Neither the electrode in electrode assembly 210 nor the distal end 204 of catheter shaft 202 is configured as the other of the cathode or anode. Instead, during electroporation, the other of the cathode or anode is positioned as a pad-dispersive electrode located on the patient. An electric field is formed between the housing and any other activating electrode or distal end 204 of electrode assembly 210 and the pad-dispersive electrode.

[0079] By applying an insulator 230 to the housing 212 to enhance the performance of the catheter 200 in bipolar mode, the electrode assembly 210 projects a suboptimal asymmetric electric field in unipolar mode, which can vary based on the orientation of the housing 212 and the target tissue. In an embodiment, the exposed axial electrode 208 is also configured to carry the same electrical signal to generate the electric field when the catheter is configured to operate in unipolar mode. For example, the lead conductors in the shaft 202, electrically connected to the exposed axial electrode 208, are configured to carry the same electrical signal as that provided to the housing 212 to generate the electric field. The result is a more omnidirectional electric field in unipolar mode, particularly relative to the distal end 228.

[0080] Figure 3A and Figure 3B Electroporation catheters 300 and 350, or distal portions 305 and 355 of electroporation catheters, are shown, both embodiments constructed based on catheter 200. Catheters 300 and 350 each include an elongated shaft 302 and 352 having a proximal end defining an axis A and opposing distal ends 304 and 354. In embodiments, shafts 302 and 352 each include exposed electrodes 308 and 358, such as annular electrodes. Distal regions 305 and 355 are configured to be deployed near target tissue. Each catheter 300 and 350 includes electrode assemblies 310 and 360, respectively, coupled to and extending distally from the distal ends 304 and 354 of the respective elongated shafts 302 and 352. Electrode assemblies 310 and 360 are each convertible between a constricted state and an expanded state. In the illustrated embodiment, electrode assemblies 310 and 360 are in an expanded state. Electrode assemblies 310 and 360 each include conductive housings 310 and 360, which include a plurality of conductive struts 312 and 362 defining a spherical shape in an expanded state. Housings 312 and 362 each include proximal portions 320 and 370, which respectively include proximal ends 322 and 372 connected to elongated shafts 302 and 352. Housings 312 and 362 extend distally along axis A to corresponding central portions 324 and 374, including the maximum radial dimension, and to distal portions 326 and 376, respectively, converging at distal ends 328 and 378. Insulators 330 and 380 are respectively disposed on at least the proximal portions 320 and 370 of housings 312 and 362, and respectively surround the conductive struts 314 and 364. Insulators 330 and 380 extend continuously from the proximal ends 322 and 372 to the intermediate portions 324 and 374, respectively.

[0081] Electroporation conduits 300 and 350 respectively show generally spherical housings 312 and 362 formed by a plurality of interconnected struts 314 and 364. The struts 314 and 364 are arranged in multiple units joined together at joints on the housings 312 and 362, forming a grid. The grid is expandable and contractible, and in an expanded configuration expands into an operable spherical form. In embodiments, the grid struts 314 and 364 are constructed of a conductive shape memory material, and the grid operates as a single ablation electrode of the electrode assemblies 310 and 360. In some embodiments, the grid struts and units are arranged symmetrically around the housing. In other embodiments, the grid struts are unevenly distributed around the housing to provide more conductive surface at the more distal portions 326 and 376, respectively. In the illustrated embodiments, electrode assemblies 310 and 360 include sensing electrodes 348 and 398 and distal end electrodes 349 and 399 attached to mesh housings 312 and 362, respectively. In some embodiments, the distal end electrodes may be configured as sensing electrodes.

[0082] Insulators 330 and 380 are respectively disposed on at least the proximal portions 320 and 370 of the mesh housings 312 and 362, and respectively surround the conductive supports 314 and 364. Insulators 330 and 380 extend continuously from the proximal ends 322 and 372 to the middle portions 324 and 374, respectively. In one embodiment, Figure 3A The diagram shows an insulator 330 positioned on the conductive struts 314 of the electrode assembly 310 from axis 304 to the housing equator 332, which coincides with the maximum dimension (diameter) of the electrode assembly 310 measured perpendicularly from axis A. The conductive surface of the strut 314 located near the equator 332 is completely surrounded by the insulator 330. In the illustrated example, the conductive strut 314 located far from the equator 332 is exposed, while the conductive strut located near the equator 332 is surrounded by the insulator 330. In another embodiment, Figure 3B An insulator 380 is shown disposed on a conductive pillar 364 of an electrode assembly 360, extending distally from an axis 354 to the housing equator 382, ​​and onto a chord 384 in a plane perpendicular to axis A. In the illustrated example, the conductive pillar 364 distal to the chord 384 is exposed, while the conductive pillar proximal to the chord 384 is surrounded by an insulator 330.

[0083] In one set of examples, electroporation conduits 300, 350 are configured for bipolar operation and compared to conduits without insulation on conductive struts in the housing. During bipolar operation of the conduit, the housing is configured as either an anode or a cathode, and a second set of one or more electrodes (e.g., exposed axial electrodes) located at the distal portion of the conduit are configured as the other of the cathode and anode to generate an electric field via electrical pulses.

[0084] In the first set of examples, the expansion shells of the three conduits each have an 8 mm diameter, and a 2 kV pulse is applied. In the example of the conduit with an 8 mm diameter shell but no insulation, the predicted damage width is 17 mm, and the predicted damage depth is 5.0 mm. In the example of conduit 300, which has an 8 mm diameter shell 312 that covers the insulation 330 proximally to the equator 332, while the conductive strut 314 located distal to the equator 332 is exposed, the predicted damage width is 18 mm, and the predicted damage depth is 6.0 mm. In the example of conduit 350, which has an 8 mm diameter shell 362 that covers the insulation 380 proximally to the chord 382, ​​while the conductive strut 364 located distal to the chord is exposed, approximately two-thirds of the shell 362 covers the insulation 380, the predicted damage width is 19 mm, and the predicted damage depth is 6.6 mm.

[0085] In the second set of examples, each of the three conduits has an expansion shell with a diameter of 7 mm, and a 2 kV pulse is applied. In the example of the conduit with a 7 mm diameter shell but no insulation, the predicted damage width is 17 mm, and the predicted damage depth is 5.5 mm. In the example of conduit 300, which has a 7 mm diameter shell 312 that covers the insulation 330 proximally to the equator 332, while the conductive strut 314 located distal to the equator 332 is exposed, the predicted damage width is 18 mm, and the predicted damage depth is 6.1 mm. In the example of conduit 350, which has a 7 mm diameter shell 362 that covers the insulation 380 proximally to the chord 382, ​​while the conductive strut 364 located distal to the chord is exposed, approximately two-thirds of the shell 362 covers the insulation 380, the predicted damage width is 18 mm, and the predicted damage depth is 6.8 mm.

[0086] Figure 4A and Figure 4BElectroporation catheters 400 and 450, or distal portions 405 and 455 of electroporation catheters, are shown, both embodiments constructed based on catheter 200. Catheters 400 and 450 each include an elongated shaft 402 and 452 having a proximal end defining an axis A and opposing distal ends 404 and 454. In embodiments, shafts 402 and 452 each include exposed electrodes 408 and 458, such as annular electrodes. Distal regions 405 and 455 are configured to be deployed near target tissue. Each catheter 400 and 450 includes electrode assemblies 410 and 460, respectively, coupled to and extending distally from the distal ends 404 and 454 of the respective elongated shafts 402 and 452. Electrode assemblies 410 and 460 are each convertible between a constricted state and an expanded state. In the illustrated embodiment, electrode assemblies 410 and 460 are in an expanded state. Electrode assemblies 410 and 460 include conductive baskets 410 and 460, respectively, comprising a plurality of conductive struts configured as support bars 412 and 462, defining a spherical shape in an expanded state. Baskets 412 and 462 each include proximal portions 420 and 470, respectively, including proximal ends 422 and 472 connected to elongated shafts 402 and 452. Baskets 412 and 462 extend distally along axis A, respectively, to corresponding central portions 424 and 474 including maximum radial dimensions and distal portions 426 and 476 converging at distal ends 428. Insulators 430 and 480 are respectively disposed on at least the proximal portions 420 and 470 of baskets 412 and 462, and respectively surround conductive struts 414 and 464. Insulators 430 and 480 extend continuously from the proximal ends 422 and 472 to the intermediate portions 424 and 474, respectively.

[0087] Electroporation conduits 400 and 450 respectively show generally spherical basket-like shells 412 and 462, formed by a plurality of pillars of support strips 414 and 464 respectively configured to extend longitudinally. The baskets 412 and 462 are expandable and retractable, and in an expanded configuration expand into an operable spherical shape. In embodiments, the support strips 414 and 464 are constructed of a conductive shape memory material, and the pillars of the baskets operate as individual ablation electrodes of electrode assemblies 410 and 460. In some embodiments, the support strips are arranged symmetrically around the basket. In other embodiments, the support strips are positioned non-uniformly around the basket to provide more conductive surface near one side of the basket. In the illustrated embodiments, electrode assemblies 410 and 460 respectively include sensing electrodes 448 and 498 attached to the support strips 414 and 464, and in some embodiments, the distal end electrodes may be configured as sensing electrodes.

[0088] Insulators 430 and 480 are respectively disposed on at least the proximal portions 420 and 470 of the support bars 414 and 464 of the basket-shaped members 412 and 462, and respectively surround the conductive support bars 414 and 464. Insulators 430 and 480 extend continuously from the proximal ends 422 and 472 to the middle portions 424 and 474, respectively. In one embodiment, Figure 4A An insulator 430 is shown positioned distally from axis 404 onto the conductive support strip 414 of electrode assembly 410, extending to the equator 432 of a basket-like element. This equator coincides with the maximum dimension (diameter) of electrode assembly 410, as measured perpendicularly from axis A to chord 434 in a plane perpendicular to axis A. The conductive surface of the support strip 414 proximal to chord 434 is completely surrounded by the insulator 430. In the illustrated example, the conductive support strip 414 distal to chord 434 is exposed, while the conductive support strip proximal to chord 434 is surrounded by the insulator 430.

[0089] In another embodiment, Figure 4B An insulator 480 is shown positioned on the conductive support strip 464 of the electrode assembly 460 from axis 454 to the basket equator 482 located in a plane perpendicular to axis A. In the illustrated example, the conductive strut located near the equator 482 is surrounded by an insulator 430. Another insulator, or a second insulator 486, is selectively disposed on the support strip 464 located far from the equator 484 to selectively shape the electric field. For example, the second insulator 486 may be applied to the portion of the support strip 464 facing the internal cavity C, such as from the equator 482 distal to the chord 484 in a plane perpendicular to axis A, and located far from the equator 482. In an embodiment, the second insulator 486 may be applied to some or all of the inner surface of the support strip 464, i.e., the surface facing the internal cavity C. In an embodiment, the conductive surface of the support strip 464 located far from the chord 484 is fully exposed. Various configurations of the second insulator 486 combined with the exposed portion of the insulator 480 and the support bar 464 located far from the equator 482 are envisioned.

[0090] Figure 5A and Figure 5BTwo examples of electric field vectors generated by a basket-shaped conduit 500 are shown. The basket-shaped conduit 500 includes an elongated shaft 502 having a proximal end defining an axis A and an opposing distal end 504. In this embodiment, the shaft 502 includes exposed electrodes 508, such as electrodes 508a and 508b. The conduit 500 includes an electrode assembly 510 coupled to and extending distally from the distal end 504 of the elongated shaft 502. In the illustrated embodiment, the electrode assembly 510 is in an expanded state. The electrode assembly 510 includes a conductive basket 512 comprising a plurality of conductive struts configured as support bars 514, defining a spherical shape in the expanded state. An insulator 530 is disposed on the basket 512 from the proximal end 522 to the basket equator 532 and surrounds the conductive support bars 514. The insulator 530 extends continuously from the proximal end 522 to the equator 532.

[0091] Figure 5A An electric field vector 540 generated via the conduit 500 operating in bipolar mode is shown. During bipolar operation of the conduit 500, the basket 512 is configured as the anode (or cathode), while the exposed axial electrodes 508a, 508b are configured as the cathode (or anode) to generate the electric field. An insulator 530 disposed on the basket 512 focuses the electroporation energy, rather than projecting it radially and symmetrically in all directions from the spherical basket 512. Therefore, the insulator 530 is disposed on the support bar, particularly at the proximal portion 220, and further distally to the equator 532, to reduce the possibility of arcing.

[0092] Figure 5B An electric field vector 542 generated via the catheter 500 operating in unipolar mode is shown. The basket-shaped element 512 is configured as either an anode or a cathode. None of the electrodes in the electrode assembly 510 or the distal end 504 of the catheter shaft 502 is configured as either a cathode or anode. Instead, the other cathode or anode is provided as a pad-dispersive electrode. An electric field is formed between the housing and any other activating electrode or distal end 504 of the electrode assembly 510 and the pad-dispersive electrode. By applying an insulator 530 to the housing 212 to enhance the performance of the catheter 500 in bipolar mode, the electrode assembly 510 projects a suboptimal asymmetric electric field in unipolar mode, which can vary based on the orientation of the housing 512 towards the target tissue. In an embodiment, the exposed shaft electrodes 508a, 508b are also configured to carry the same electrical signal to generate the electric field when the catheter 500 is configured to operate in unipolar mode. If the electrode assembly includes a sensing electrode 548 coupled to the basket 512, the sensing electrode 548 can be activated with the same electrical signal to generate an electric field in the support bar 514 to selectively shape the electric field vector 542. The result is a more omnidirectional electric field in unipolar mode.

[0093] Various modifications and additions may be made to the exemplary embodiments discussed without departing from the scope of this disclosure. For example, while the above embodiments relate to specific features, the scope of the invention also includes embodiments having different combinations of features and embodiments that do not include all of the stated features. Therefore, the scope of the invention is intended to cover all such alternatives, modifications, and variations falling within the scope of the claims, as well as all their equivalents.

Claims

1. An electroporation catheter for ablating cardiac tissue, the electroporation catheter comprising: An elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis; An electrode assembly is coupled to and extends distally from the distal end of the elongated shaft, the electrode assembly being convertible between a contracted state and an expanded state, wherein the electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposite the elongated shaft; and A proximal insulating portion, disposed on the proximal portion of the electrode assembly, surrounds each of the plurality of conductive pillars, the proximal insulating portion extending from the proximal end to at least the central portion.

2. The electroporation catheter according to claim 1, wherein, The ablation electrode in the expanded state has a maximum radial dimension that is larger than the maximum radial dimension of the distal region of the elongated axis.

3. The electroporation catheter according to claim 2, wherein, The maximum radial dimension of the ablation electrode defines the equator on the electrode assembly.

4. The electroporation catheter according to claim 3, wherein, The proximal insulating portion is disposed on the conductive post from the proximal end to the equator.

5. The electroporation catheter according to claim 3, wherein, The proximal insulator is disposed on the conductive strut from the proximal end to the chord on the electrode assembly located far from the equator.

6. The electroporation catheter according to any one of claims 1-5, wherein, The conductive pillars form a mesh shell.

7. The electroporation catheter according to claim 6, wherein, The conductive pillars are arranged in multiple units on the grid shell.

8. The electroporation catheter according to any one of claims 1-5, wherein, The conductive pillars form multiple longitudinally extending support strips to form a basket-shaped outer shell.

9. The electroporation catheter according to any one of claims 1-8, further comprising an axial electrode disposed on the distal region of the axial axis.

10. The electroporation catheter according to claim 9, wherein, The electrode assembly and axial electrode are configured as either a cathode or an anode to generate an electric field in unipolar mode.

11. The electroporation catheter according to claim 9, wherein, The electrode assembly is configured as one of a cathode and an anode, and the axial electrode is configured as the other of an anode and a cathode to generate an electric field in bipolar mode.

12. The electroporation catheter according to any one of claims 1-11, further comprising a plurality of sensing electrodes disposed on the electrode assembly.

13. The electroporation catheter according to claim 12, wherein, The electrode assembly includes a plurality of electrodes configured as either a cathode or an anode to generate an electric field in unipolar mode.

14. The electroporation conduit according to any one of claims 1-13, further comprising a second insulator selectively disposed on the conductive post, located distal to the proximal insulating portion.

15. The electroporation catheter according to claim 14, wherein, The second insulator is disposed on the inner surface of one of the plurality of conductive pillars, the inner surface facing the internal cavity of the electrode assembly, and the outer surface of the pillar among the plurality of conductive pillars is exposed.

16. An electroporation catheter for ablating cardiac tissue, said electroporation catheter comprising: An elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis; An electrode assembly is coupled to and extends distally from the distal end of the elongated shaft, the electrode assembly being convertible between a contracted state and an expanded state, wherein the electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposite the elongated shaft; and A proximal insulating portion, disposed on the proximal portion of the electrode assembly, surrounds each of the plurality of conductive pillars, the proximal insulating portion extending from the proximal end to at least the central portion.

17. The electroporation catheter according to claim 16, wherein, The ablation electrode in the expanded state has a maximum radial dimension that is larger than the maximum radial dimension of the distal region of the elongated axis.

18. The electroporation catheter according to claim 17, wherein, The maximum radial dimension of the ablation electrode defines the equator on the electrode assembly.

19. The electroporation catheter according to claim 18, wherein, The proximal insulating portion is disposed on the conductive post from the proximal end to the equator.

20. The electroporation catheter according to claim 18, wherein, The proximal insulator is disposed on the conductive strut from the proximal end to the chord on the electrode assembly located far from the equator.

21. The electroporation catheter according to claim 16, wherein, The conductive pillars form a mesh shell.

22. The electroporation catheter according to claim 21, wherein, The conductive pillars are arranged in multiple units on the grid shell.

23. The electroporation catheter according to claim 16, wherein, The conductive support includes multiple longitudinally extending support bars to form a basket-shaped outer shell.

24. The electroporation catheter of claim 16, further comprising an axial electrode disposed on a distal region of the axial axis.

25. The electroporation catheter according to claim 24, wherein, The electrode assembly and axial electrode are configured as either a cathode or an anode to generate an electric field in unipolar mode.

26. The electroporation catheter according to claim 24, wherein, The electrode assembly is configured as one of a cathode and an anode, and the axial electrode is configured as the other of an anode and a cathode to generate an electric field in bipolar mode.

27. The electroporation catheter of claim 16, further comprising a plurality of sensing electrodes disposed on the electrode assembly.

28. The electroporation catheter according to claim 27, wherein, The electrode assembly includes a plurality of electrodes configured as either a cathode or an anode to generate an electric field in unipolar mode.

29. The electroporation conduit of claim 16, further comprising a second insulator selectively disposed on the conductive post, located distal to the proximal insulating portion.

30. The electroporation catheter according to claim 29, wherein, The second insulator is disposed on the inner surface of one of the plurality of conductive pillars, the inner surface facing the internal cavity of the electrode assembly, and the outer surface of the pillar among the plurality of conductive pillars is exposed.

31. An electrophysiological system, comprising: An electroporation control console, configured to generate pulsed electrical signals for electroporation ablation; and Electroporation catheter, connected to the electroporation control console, the electroporation catheter comprising: An elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis; An electrode assembly, coupled to and extending distally from the distal end of the elongated shaft, is capable of switching between a contracted state and an expanded state. The electrode assembly includes a plurality of conductive struts defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having a maximum radial dimension, and a distal portion opposite the elongated shaft. A proximal insulating portion, disposed on the proximal portion of the electrode assembly, surrounds each of the plurality of conductive pillars, the proximal insulating portion extending from the proximal end to at least the central portion.

32. The electrophysiological system according to claim 31, wherein, The electroporation catheter is configured to operate in both bipolar and unipolar modes.

33. An electroporation catheter for ablating cardiac tissue, said electroporation catheter comprising: An elongated shaft having a proximal end and an opposing distal end, the elongated shaft defining an axis and including an axis electrode disposed on the distal end; An electrode assembly, coupled to and extending distally from the distal end of the elongated shaft, is capable of switching between a contracted and an expanded state. The electrode assembly includes multiple conductive pillars defining a spherical shape in the expanded state, including a proximal portion coupled to the elongated shaft, a central portion having the largest radial dimension, and a distal portion opposite the elongated shaft. The electrode assembly is operable in unipolar and bipolar modes. A proximal insulating portion is disposed on the proximal portion of the electrode assembly, surrounding each of the plurality of conductive pillars, the proximal insulating portion extending from the proximal end to at least the central portion; The electrode assembly and axial electrode are configured as either a cathode or an anode to generate an electric field in the unipolar mode, and The electrode assembly is configured as one of a cathode and an anode, and the axial electrode is configured as the other of an anode and a cathode, to generate an electric field in the bipolar mode.

34. The electroporation catheter according to claim 33, wherein, The ablation electrode in the expanded state includes a maximum radial dimension larger than the maximum radial dimension of the distal region of the elongated shaft, and wherein the proximal insulator is disposed on the conductive strut from the proximal end to a chord on the electrode assembly located distal to the maximum radial dimension.

35. The electroporation catheter according to claim 33, wherein, The conductive pillars form one of a mesh shell and a basket-shaped shell.

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