Catheter with asymmetric field delivery

Abstract

An electroporation catheter for cardiac tissue ablation is disclosed. The electroporation catheter includes an elongate shaft having a distal region and a deflection plane. The elongate shaft defines an axis. An electrode assembly is operably coupled to the distal region and configured to generate an electric field. The electrode assembly includes a plurality of splines, each supporting an ablation electrode. The splines are transitionable between a contracted configuration and an expanded configuration. A deflector in the distal region is operable in the expanded configuration to deflect the electrode assembly off-axis toward a deflection direction in the deflection plane. In the expanded configuration, a first set of the splines is proximal to the deflection direction, and a second set of the splines is distal to the deflection direction. Insulators are disposed on the second set of the splines to insulate at least a portion of each associated ablation electrode.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to medical systems and methods for facilitating the ablation of tissue in a patient, and more particularly, to medical systems and methods for facilitating the ablation of tissue by electroporation. [Background technology]

[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. Ablation is typically achieved through thermal ablation techniques, including radiofrequency (RF) ablation and cryoablation. In RF ablation, a probe is inserted into the patient, and radiofrequency waves are transmitted through the probe to surrounding tissue. The radiofrequency waves generate heat, which destroys surrounding tissue and cauterizes blood vessels. In cryoablation, a hollow needle or cryoprobe is inserted into the patient, and a low-temperature, heat-conducting fluid is circulated through the probe, freezing and killing surrounding tissue. RF ablation and cryoablation techniques can indiscriminately kill tissue through cellular necrosis, which can damage or kill other healthy tissue, such as tissue in the esophagus, phrenic nerve cells, and tissue in the coronary arteries.

[0003] Another ablation technique uses electroporation. In electroporation, or electropermeabilization, 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 and duration of the electric field. If electroporation is reversible, the temporarily increased permeability of the cell membrane can be used to introduce chemicals, drugs, or deoxyribonucleic acid (DNA) into the cells prior to cellular healing and recovery. Tissue recovery can occur over minutes, hours, or days after ablation is complete. If electroporation is irreversible, the affected cells die, for example, via a form of cell death (e.g., programmed cell death, possibly via apoptosis, or traumatic cell death, e.g., via necrosis).

[0004] Irreversible electroporation can be used as a non-thermal ablation technique. Irreversible electroporation uses a train of brief, high-voltage pulses to generate an electric field strong enough to kill cells. For cardiac tissue ablation, irreversible electroporation can be a relatively safe and effective alternative to the indiscriminate killing of thermal ablation techniques such as RF ablation and cryoablation. Irreversible electroporation can be used to kill target tissue, such as myocardial tissue, by selecting an electric field strength and duration that is ineffective at permanently killing other cells or tissues, such as non-target myocardial tissue, red blood cells, vascular smooth muscle tissue, endothelial tissue, and nerve cells. Summary of the Invention

[0005] Example 1 provides an electroporation catheter for cardiac tissue ablation. The electroporation catheter includes an elongate shaft, an electrode assembly, a deflector, and an insulator. The elongate shaft includes a distal region and a deflection plane, the elongate shaft defining an axis. The electrode assembly is operably coupled to the distal region and configured to generate an electric field. The electrode assembly includes a plurality of splines, each supporting an associated ablation electrode. The splines are transitionable between a contracted state and an expanded state. The deflector is present in the distal region. The deflector is operable in the expanded state to deflect the electrode assembly off-axis toward a deflection direction in the deflection plane. In the expanded state, the electrode assembly includes a first set of splines proximal to the deflection direction and a second set of splines distal to the deflection direction. The insulator is disposed on the second set of splines to insulate at least a portion of the associated ablation electrode.

[0006] In Example 2, in the electroporation catheter of Example 1, the plurality of splines form a basket that defines a cavity in the expanded state, and the insulator directs the electric field from each ablation electrode associated with the second set of the plurality of splines into the cavity.

[0007] In Example 3, in the electroporation catheter of Example 2, the basket is guidable toward the treatment site by a deflector. In Example 4, in the electroporation catheter of any of Examples 1 to 3, the electrode assembly is configured as one of a cathode and an anode to generate an electric field in a monopolar mode.

[0008] In Example 5, the electroporation catheter of Example 4, wherein the shaft includes a lead conductor, and each of the plurality of associated ablation electrodes is electrically connected to the lead conductor.

[0009] In Example 6, in the electroporation catheter of any of Examples 1 to 5, each ablation electrode associated with the second set of splines includes a surface facing the deflection direction and a surface facing opposite the deflection direction, and an insulator is disposed on the surface facing opposite the deflection direction.

[0010] In Example 7, in the electroporation catheter of any of Examples 1 to 6, each ablation electrode associated with each spline includes a surface facing the deflection direction and a surface facing the deflection direction, and an insulator is disposed on the surface facing away from the deflection direction.

[0011] In Example 8, in the electroporation catheter of any of Examples 1 to 7, each spline is formed from an associated ablation electrode. In Example 9, the electroporation catheter of any of Examples 1 to 8, wherein the electrode assembly further comprises a mapping electrode.

[0012] In Example 10, the electroporation catheter of any of Examples 1-8, each spline further comprises a mapping electrode. In Example 11, the electroporation catheter of Example 10, wherein each spline includes a longitudinal length, and each spline includes a plurality of mapping electrodes disposed along the longitudinal length.

[0013] In Example 12, in the electroporation catheter of any one of Examples 9 to 11, the mapping electrode is not covered with an insulator. In Example 13, in the electroporation catheter of Example 1, each spline includes a resilient support member coupled to an electrode.

[0014] In Example 14, the electroporation catheter of Example 13, each spline further comprises a plurality of exposed mapping electrodes. In Example 15, in the electroporation catheter of Example 1, each spline supports one associated elongated ablation electrode.

[0015] Example 16 provides an electroporation catheter for cardiac tissue ablation. The electroporation catheter includes an elongate shaft, an electrode assembly, a deflector, and an insulator. The elongate shaft includes a distal region and a deflection plane. The elongate shaft defines an axis. The electrode assembly is operably coupled to the distal region and configured to generate an electric field. The electrode assembly includes a plurality of splines, each spline supporting an associated ablation electrode. The splines are transitionable between a contracted state and an expanded state. The deflector is present in the distal region. The deflector is operable in the expanded state to deflect the electrode assembly off-axis toward a deflection direction in the deflection plane. In the expanded state, the electrode assembly includes a first set of splines proximal to the deflection direction and a second set of splines distal to the deflection direction. An insulator is disposed on the second set of splines to insulate at least a portion of the associated ablation electrode.

[0016] In Example 17, in the electroporation catheter of Example 16, the plurality of splines form a basket that defines a cavity in the expanded state, and the insulator directs the electric field from each ablation electrode associated with the second set of the plurality of splines into the cavity.

[0017] In Example 18, in the electroporation catheter of Example 17, the basket is guidable toward the treatment site by a deflector. In Example 19, in the electroporation catheter of Example 16, the electrode assembly is configured as one of a cathode and an anode to generate an electric field in a monopolar mode.

[0018] In Example 20, the electroporation catheter of Example 19, wherein the shaft includes a lead conductor, and each of the associated ablation electrodes is electrically connected to the lead conductor.

[0019] In Example 21, in the electroporation catheter of Example 16, each ablation electrode associated with the second set of splines includes a surface facing the deflection direction and a surface facing away from the deflection direction, and an insulator is disposed on the surface facing away from the deflection direction.

[0020] In Example 22, in the electroporation catheter of Example 21, each ablation electrode associated with each of the plurality of splines includes a surface facing the deflection direction and a surface facing the deflection direction, and an insulator is disposed on the surface facing away from the deflection direction.

[0021] In Example 23, the electroporation catheter of Example 16, wherein the ablation electrodes associated with the first set of the plurality of splines are exposed. In Example 24, the electroporation catheter of Example 16, each spline further comprises a mapping electrode.

[0022] In Example 25, the electroporation catheter of Example 24, wherein each spline includes a plurality of exposed mapping electrodes disposed along the spline. Example 26 provides an electroporation catheter for cardiac tissue ablation. The electroporation catheter includes an elongate shaft, an electrode assembly, a deflector, and an insulator. The elongate shaft includes a distal region and a deflection plane. The elongate shaft defines an axis. The electrode assembly is operably coupled to the distal region and configured to generate an electric field. The electrode assembly includes a plurality of elongate ablation electrodes configured as a plurality of splines. Each ablation electrode includes an outer conductive surface and an inner conductive surface, and each spline supports a mapping electrode. The splines are transitionable between a contracted state and an expanded state. The deflector is present in the distal region. The deflector is operable in the expanded state to deflect the electrode assembly off-axis toward a deflection direction in the deflection plane. In the expanded state, the electrode assembly includes a first set of splines proximal to the deflection direction and a second set of splines distal to the deflection direction. An insulator is disposed on the second set of the plurality of splines to insulate at least a portion of the outer conductive surface and expose the mapping electrodes.

[0023] In Example 27, the electroporation catheter of Example 26, wherein the plurality of splines form a basket that defines a cavity in the expanded state, and each inner conductive surface faces the cavity.

[0024] In Example 28, the electroporation catheter of Example 27, wherein the insulator disposed on the second set of the plurality of splines does not insulate the inner conductive surface. In Example 29, in the electroporation catheter of Example 28, an insulator is further disposed on the first set of splines so as to insulate the inner conductive surface of the first set of splines and not insulate the outer conductive surface of the first set of splines.

[0025] In Example 30, the electroporation catheter of Example 26, wherein the shaft includes a lead conductor, and each of the ablation electrodes is electrically connected to the lead conductor. Example 31 describes a method for making an electroporation catheter for cardiac tissue ablation. An elongate shaft having a distal region and a deflection plane is provided. The elongate shaft defines an axis. An electrode assembly is coupled to the distal region. The electrode assembly is configured to generate an electric field. The electrode assembly includes a plurality of splines, each supporting an associated ablation electrode. The splines are movable between a contracted state and an expanded state. A deflector is provided in the distal region. The deflector is operable in the expanded state to deflect the electrode assembly off-axis toward a deflection direction in the deflection plane. In the expanded state, the electrode assembly includes a first set of splines proximal to the deflection direction and a second set of splines distal to the deflection direction. Insulation is deposited on the second set of splines to insulate at least a portion of the associated electrode.

[0026] In Example 32, in the method of Example 31, preparing the shaft includes providing a lead conductor within the shaft, and further includes electrically connecting each of the plurality of associated ablation electrodes to the lead conductor.

[0027] In Example 33, the method of Example 31, wherein each of the plurality of splines is formed from an associated ablation electrode. In Example 34, the method of Example 33 further includes forming each of the plurality of splines to form a basket in the expanded state.

[0028] In Example 35, the method of Example 31 further includes attaching a plurality of mapping electrodes to each spline, and wherein no insulator is deposited on the plurality of mapping electrodes. While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic illustrating an exemplary clinical environment for treating a patient and for treating the patient's heart using an electrophysiological system according to an embodiment of the presently disclosed subject matter. [Figure 2] FIG. 2 is a schematic diagram illustrating an exemplary catheter that may be used in the exemplary electrophysiology system of FIG. 1. [Figure 3A] 3 is a cross-sectional schematic front view of a first exemplary electrode assembly that may be used in the exemplary catheter of FIG. 2. FIG. [Figure 3B] 3 is a cross-sectional schematic front view of a second exemplary electrode assembly that may be used in the exemplary catheter of FIG. 2. FIG. [Figure 3C] FIG. 3 is a front cross-sectional schematic view of a third exemplary electrode assembly that may be used in the exemplary catheter of FIG. 2. [Figure 3D] FIG. 3 is a cross-sectional schematic front view of a fourth exemplary electrode assembly that may be used in the exemplary catheter of FIG. 2. [Figure 3E] FIG. 10 is a cross-sectional schematic front view of a fifth exemplary electrode assembly that may be used in the exemplary catheter of FIG. 2. [Figure 4] FIG. 3E is a top view of a portion of the fourth exemplary electrode assembly of FIG. 3D. [Figure 5] 3 is a perspective view of a distal portion of an exemplary spline catheter for use in the electrophysiology system of FIG. 1 according to the exemplary catheter of FIG. 2. FIG. [Figure 6] FIG. 6 is a schematic cross-sectional front view of a portion of the electrode assembly of the exemplary spline catheter of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0030] While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention 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.

[0031] For purposes of promoting an understanding of the principles of the present disclosure, reference will be made to the examples illustrated in the drawings described below. The illustrative examples disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise form disclosed in the following detailed description. Rather, these exemplary embodiments were chosen and described so that those skilled in the art might use their teachings. The use of multiple (e.g., all) features across all examples would not be beyond the scope of the present disclosure. Thus, no figure should be interpreted as having any dependency or requirement relating to any single component or combination of components shown. In addition, various components shown in the figures may, in some examples, be combined with various of the other components shown (or components not shown), all of which are considered to be within the scope of the present disclosure.

[0032] As applied to electrophysiological systems, irreversible electroporation uses high-voltage, short pulses to kill cells, such as myocardial cells, by apoptosis while sparing other adjacent tissues, including esophageal vascular smooth muscle and endothelium. Irreversible electroporation treatments can be performed in multiple treatment sections. Treatment sections, which may have durations on the order of milliseconds, can include multiple electrical pulses, such as tens of pulses, generated and delivered by an electroporation device powered by an electroporation generator to generate an electric field of sufficient strength to form a transmural lesion. Such pulsed electric field ablation generates a generally spherical electric field around a generally point-like electrode, or a field with a generally circular cross-section around a generally linear electrode, that is generally independent of tissue or blood within the heart. Such electric fields may potentially cause collateral damage to adjacent regions on the blood pool side of the electrode or opposite the target tissue. In contrast, RF ablation can be focused on the area of ​​direct contact with the electrode.

[0033] Electroporation devices for ablation and cardiac mapping, such as mapping and ablation catheters, are typically larger in size than many RF ablation catheters. For example, the working ends of mapping and ablation catheters can be 7 mm to 15 mm or larger in diameter. Such catheters often generate relatively large electric fields for ablation, which increases the likelihood of collateral damage to areas opposite the myocardial target tissue.

[0034] 1 illustrates an exemplary clinical environment 10 for treating a patient 20 (e.g., for treating a heart 30 of the patient 20) using an electrophysiology system 50 according to the present disclosure. The electrophysiology system 50 includes an electroporation catheter system 60 and an electro-anatomical mapping (EAM) system 70. The exemplary electroporation catheter system 60 includes an electroporation catheter 105, an introducer sheath 110, and an electroporation console 130. In addition, the electroporation catheter system 60 includes various connecting elements (e.g., cables) that operably connect the components of the electroporation catheter system 60 to each other and to the components of the EAM system 70. Generally, the EAM mapping system 70 includes a localization field generator 80, a mapping and navigation controller 90, and a display 92. The clinical environment 10 may also include additional equipment, such as imaging equipment 94 (represented by a C-arm), and various controller elements (e.g., foot controller 96) configured to allow an operator to control various aspects of the electrophysiology system 50. The clinical environment 10 may have other components and arrangements of components not shown in FIG.

[0035] Electroporation catheter system 60 is configured to deliver ablative electric field energy to target tissue within the patient's heart 30 to cause cell death in the tissue, e.g., to render the tissue unable to transmit electrical signals. Electroporation catheter system 60 is also configured to generate electric fields using electroporation catheter 105 and to create and present an electroanatomical map of the patient's heart on display 92 to assist a clinician in planning irreversible electroporation ablation using electroporation catheter 105 prior to delivery of the ablative electric field energy. In embodiments, electroporation catheter system 60 is configured to generate electric fields based on characteristics of electroporation catheter 105 and the position of electroporation catheter 105 within patient 20 (e.g., within heart 30 of patient 20). Electroporation catheter system 60 is configured to generate a graphical representation of the electroporation catheter and an electroanatomical map based on characteristics of electroporation catheter 105, the position of electroporation catheter 105 within patient 20 (e.g., within heart 30 of patient 20), and characteristics of the tissue surrounding catheter 105 (e.g., measured tissue impedance). In one example, electroporation catheter 105 is a mapping and ablation catheter that can be deployed in a mapping procedure in cooperation with EAM system 70 to deliver ablative field energy and ablate tissue via irreversible electroporation.

[0036] The introducer sheath 110 is operable to provide a delivery conduit through which the electroporation catheter 105 may be deployed to a specific target site within the patient's heart 30. Access to the patient's heart may be achieved through a blood vessel (e.g., a peripheral artery or vein). Once vascular access is gained, the electroporation catheter 105 may be guided into the patient's heart (e.g., into a chamber of the heart).

[0037] An exemplary electroporation catheter 105 includes an elongate catheter shaft and a distal end region configured to be deployed near a target tissue (e.g., within a patient's heart chamber). The shaft extends from an access point within the patient to the target tissue and generally defines a longitudinal axis of the electroporation catheter 105. The distal end region may include a basket, balloon, splines, a configured tip, or other electrode deployment mechanism coupled to the shaft. The electrode deployment mechanism includes an electrode assembly or electrode array comprising electrodes. For example, the electrode assembly may include multiple spaced electrodes, multiple sets of spaced electrodes, or multiple groups of spaced electrodes. In some examples, electrodes (e.g., multiple spaced electrodes) may be deployed on the catheter shaft in addition to or instead of electrodes on the electrode deployment mechanism. For example, the electrode deployment mechanism may include multiple splines configured to form a basket, with at least some of the multiple electrodes disposed on the splines.

[0038] The electroporation catheter 105 can be configured into multiple configurations. For example, when the distal end region of the catheter 105 is within a sheath as a catheter assembly (e.g., for movement into a chamber of a patient's heart), the electrode deployment mechanism and electrode assembly are in a contracted state to fit within the sheath. Once the catheter reaches a desired location, e.g., within a chamber of the heart, the sheath can be withdrawn from the distal region of the catheter 105 (or the shaft catheter can be extended beyond the sheath), and the electrode deployment mechanism and electrode assembly can be positioned in an expanded state. The electrode assembly has a contracted shape when the catheter 105 is in the contracted state and an expanded shape when the catheter 105 is in the expanded state. In some examples, the electrode assembly has two or more states.

[0039] In one example, the multiple electrodes may be formed from a conductive solid surface biocompatible material and spaced apart via an insulator. Each of the multiple electrodes is electrically connected to a corresponding elongated lead conductor that extends along the shaft to the proximal end of the catheter. In one example, each electrode of the multiple spaced apart electrodes corresponds to a separate single lead conductor. In another example, multiple electrodes may be connected to a single lead conductor. Other configurations are also contemplated. The multiple lead conductors may be insulated from each other along the catheter shaft within an insulating sheath (e.g., an insulating polymer sheath). The multiple lead conductors may be electrically connected to a plug in the proximal region of the electroporation catheter 105 (e.g., a plug configured for mechanical and electrical connection to the electroporation console 130), for example, directly or via an intermediate electrical conductor such as cable wiring.

[0040] The electroporation console 130 includes a controller (e.g., one or more controllers, processors, or computers) that executes instructions or code (e.g., processor-executable instructions) from a non-transitory computer-readable medium (e.g., a memory device or memory) to, for example, control or perform aspects of the electroporation catheter system 60. In one example, the electroporation console 130 is configured to provide electrical signals (e.g., multiple simultaneous or time-spaced electrical signals) to the electroporation catheter 105, which is electrically connected along lead conductors to spaced-apart electrodes. The spaced-apart electrodes are configured to generate selected electric fields near the target tissue to perform ablation based on the electrical signals from the electroporation console 130.

[0041] The electroporation console 130 can generate electrical signals and select which electrodes in the electrode array receive the electrical signals. By selecting a first electrode or a first group of electrodes as the anode and a different second electrode or group of electrodes as the cathode, an electric field can be generated between the anode and the cathode based on a signal (e.g., a pulse) provided to the electrodes by the electroporation console 130. The console 130 delivers electrical pulses of different lengths and magnitudes to the electrodes on the catheter 105. The electrical pulses can be delivered in a continuous pulse stream or multiple discrete pulse trains. Pulse parameters of interest include the number of pulses, the pulse duty cycle, the interval between pulse trains, the pulse voltage or pulse magnitude (including peak voltage), and the voltage duration. For example, the console 130 can select two or more electrodes in the electrode assembly and deliver pulses to the selected electrodes to generate an electric field between the selected electrodes.

[0042] In ablation mode, the console can select electrodes to perform pulsed field ablation (PFA). For example, PFA can be performed with monophasic and biphasic waveforms. Without being limited to a particular theory, field strengths in the range of approximately 200-250 volts per centimeter (V / cm) with microsecond-scale pulse durations have been demonstrated to provide reversible electroporation in cardiac tissue. Field strengths of approximately 400 V / cm have been demonstrated to provide irreversible electroporation in cardiac tissue of interest (e.g., targeted myocardial and endocardial tissues) with demonstrable sparing of red blood cells, vascular smooth muscle tissue, endothelial tissue, nerves, and other non-target nearby tissues.

[0043] Additionally, the electrode assembly on the catheter 105 can be operated in a selected mode, such as a monopolar mode or a bipolar mode. During monopolar operation of the catheter 105, an electrode, a group of electrodes, or the entire electrode assembly is configured as one of an anode or a cathode. No electrode in the electrode assembly is configured as the other of anode or cathode. Instead, the other of cathode or anode is provided in the form of a pad dispersive electrode that is placed on the patient, typically on the back, buttocks, or other suitable anatomical location, during electroporation. An electric field is formed between an active electrode of the electrode assembly and a pad dispersive electrode. In an alternative configuration, a return electrode, such as multiple return electrodes, can be positioned on the shaft of the catheter. An electric field is formed between an active electrode of the electrode assembly and a return electrode on the shaft of the catheter 105. During bipolar operation of the catheter 105, a first set of one or more electrodes of the electrode assembly is configured as an anode, and a second set of one or more electrodes of the electrode assembly is configured as a cathode to generate an electric field. In this example, no pad dispersive electrodes are used and the electric field does not extend into the patient's body, but rather through a localized portion of tissue adjacent to the electrode assembly.

[0044] In some examples, the catheter 105 may be a mapping and ablation catheter, and the electrodes may include ablation electrodes configured to deliver ablation field energy and mapping electrodes for mapping purposes. In some configurations, the mapping electrodes are configured to be used to collect electrical signals used to generate, by the operably coupled EAM system 70, a detailed three-dimensional geometric anatomical map or representation of the heart chamber, as well as an electroanatomical map in which cardiac electrical activity of interest is superimposed on the geometric anatomical map, for display by the operably coupled display 92. In some examples, the electrodes can operate as ablation electrodes in the ablation mode of the electrophysiology system 50 and as mapping electrodes in the mapping mode of the system 50. Multiple mapping electrodes on the electroporation catheter 105 can measure electrical signals and generate output signals that can be processed by the mapping and navigation controller 90 to generate an electroanatomical map. In some examples, the electroanatomical map is generated before ablation to determine the electrical activity of cardiac tissue within the heart chamber of interest. In some examples, the electroanatomical map is generated after ablation to verify desired changes in the electrical activity of the ablated tissue and heart chamber. The mapping electrodes can also be used to determine the position of the catheter 105 in three-dimensional space within the body. For example, as the operator moves the distal end of the catheter 105 within a heart chamber of interest, the boundaries of the catheter movement can be used by the mapping and navigation controller 90 to form an anatomical map of the heart chamber. The anatomical map of the heart chamber can be used to aid in navigation of the catheter 105 without the use of ionizing radiation (e.g., fluoroscopy), and to tag the location of the ablation when it is completed to guide the ablation interval and assist the clinician in ablating the anatomical structure of interest. In some examples, one electrode in the electrode assembly can be configured to perform only ablation, or one electrode in the electrode assembly can be configured to perform only mapping.

[0045] The EAM system 70 is configured to generate electroanatomical maps for display on the display 92. The EAM system 70 is operable to track the positions of various components of the electroporation catheter system 60 and generate high-fidelity three-dimensional anatomical and electroanatomical maps of the heart, including portions of the heart (e.g., a heart chamber of interest or other structure of interest (e.g., the sinoatrial node or atrioventricular node)). In one illustrative example, the EAM system 70 may include the RHYTHMIA™ HDx mapping system sold by Boston Scientific Corporation. The mapping and navigation controller 90 of the EAM system 70 may also include one or more controllers (e.g., microprocessors or computers) that execute code from memory to control or perform functional aspects of the EAM system 70, which may be part of one or more controllers, microprocessors, computers, or memory devices accessible via a computer network.

[0046] EAM system 70 generates a localization field via field generator 80 to form a localization volume around heart 30, and position sensors or sensing elements on the tracked devices (e.g., sensors on electroporation catheter 105) generate outputs that can be processed by mapping and navigation controller 90 to track the position of the sensor within the localization volume and, therefore, the corresponding device. In the illustrated example, device tracking is performed using magnetic tracking techniques, field generator 80 is a magnetic field generator that generates a magnetic field that forms the localization volume, and the position sensors on the tracked devices are magnetic field sensors.

[0047] In other examples, impedance tracking methods can be used to track the positions of various devices. In such examples, the localization fields are electric fields generated, for example, by external field generator arrangements (e.g., surface electrodes), by intrabody or intracardiac devices (e.g., intracardiac catheters), or both. In these examples, the position sensing elements can comprise electrodes on the tracked devices that generate outputs that are received and processed by the mapping and navigation controller 90 to track the positions of the various position sensing electrodes within the localization volume.

[0048] The EAM system 70 can include both magnetic and impedance tracking capabilities. In such instances, impedance tracking accuracy can be enhanced by first creating a map of the electric field induced by the electric field generator within the cardiac chamber of interest using a probe equipped with a magnetic position sensor, as is possible with the RHYTHMIA HDx™ mapping system. One exemplary probe is the INTELLAMAP ORION™ mapping catheter sold by Boston Scientific Corporation.

[0049] Regardless of the tracking method used, EAM system 70 utilizes the positional information of the various tracking devices and cardiac electrical activity acquired, for example, by electroporation catheter 105 equipped with sensing electrodes or another catheter or probe, to generate and display on display 92 a detailed three-dimensional geometrical anatomical map or representation of cardiac tissue and air spaces (e.g., heart chambers), as well as an electroanatomical map in which cardiac electrical activity of interest is superimposed on the geometrical anatomical map. Additionally, EAM system 70 can generate a graphical representation of the various tracked devices within the geometrical anatomical map or electroanatomical map.

[0050] The electroporation catheter system 60 can be combined or integrated with the EAM system 70 to enable visualization of a graphical representation of the electric fields that may be generated by the electroporation catheter 105 on an electroanatomical map of the patient's heart. The integrated system can include functionality that improves the efficiency of clinical workflow, including improving the provision of a clinician with a visual representation of ablation lesions in portions of the patient's heart formed through irreversible electroporation. The integrated system can include generating a graphical representation of the electric fields that may be generated by the electroporation catheter 105, generating anatomical maps, including generating electroanatomical maps, and displaying information regarding the location and field strength of the electric fields that may be generated by the electroporation catheter 105.

[0051] 1 is intended as an example or general overview of the various components of the system 50 and is not intended to imply that the present disclosure is limited to any set of components or arrangement of components. For example, additional hardware components (e.g., breakout boxes or workstations) may be included in the electrophysiology system 50.

[0052] FIG. 2 illustrates an exemplary electroporation catheter 200 for cardiac tissue ablation, which is an example of a catheter 105 and may be used with the electrophysiology system 50. The exemplary electroporation catheter 200 includes an elongate shaft 202 having a distal region 204 and a deflection surface 206. The distal region 204 is configured to be deployed near a target tissue (e.g., within a patient's heart chamber). The elongate shaft 202 defines a longitudinal axis A. The longitudinal axis A is depicted as a line passing through the center of gravity of a cross-section of the shaft 202. An electrode assembly 210 is operably coupled to the distal region 204 and configured to generate an electric field. In one example, the electric field causes irreversible electroporation in selected cardiac tissue. The electrode assembly 210 includes a plurality of splines 212, each of which supports an associated electrode 214. In one example, each spline supports an associated ablation electrode. For example, each spline supports a plurality of associated ablation electrodes. The splines 212 are transitionable between a contracted state and an expanded state. The deflector 220 resides in the distal region 204. The deflector 220 is actuatable in the expanded state to deflect the electrode assembly 210 off axis A toward a deflection direction F in the deflection plane 206. For example, the deflector 220 is coupled to the shaft 202, and the axis A is determined proximal to the deflector 220. In the expanded state, the electrode assembly 210 includes a first set 224 of splines 212 proximal to the deflection direction F and a second set 226 of splines 212 distal to the deflection direction F. For example, the first set 224 may include one or more splines, and the second set 226 may include one or more splines. Insulators 230 are disposed on the second set 226 of the plurality of splines 212 to insulate at least a portion of the associated electrodes 214. For example, the insulators 230 are disposed on the second set 226 of the plurality of splines 212 opposite the deflection direction F. The insulators 230 are not disposed on the associated electrodes 214 of the first set 224 of the plurality of electrodes.

[0053] In the illustrated example, the splines 212 form a basket 232 coupled to the shaft 202. The basket 232 may include an expanded length L and an expanded diameter D, and a particular outer shape in an expanded state. The length (e.g., length L) of the basket 232 may be determined based on the longitudinal distance of the splines 212 from the proximal end to the distal end along the basket axis X. The diameter (e.g., diameter D) of the basket 232 may be determined based on the maximum distance between opposing splines 212 in a direction approximately perpendicular to the basket axis X. In the expanded state, the splines 212 are spaced apart from one another and form a cavity C within the basket 232. In this example, the splines 212 are constructed from a flexible and elastic material such that the catheter 200 may be capable of transitioning to a contracted state (not shown) in which the contracted length of the basket 232 is greater than L and the contracted diameter of the basket is less than D. In one example, catheter 200 is placed in a contracted state while catheter 200 is in a non-operational mode with a deployment sheath positioned over splines 212. When basket 232 is extended from the deployment sheath or the deployment sheath is withdrawn from basket 232, the basket assumes an expanded state and can be deployed in an operational mode.

[0054] The deflector 220 allows the basket 232 to deflect or move off-axis A, such as toward a treatment site in the deflection plane 206. In one example, the deflector 220 allows the basket 232 to pivot or bend within the deflection plane 206 relative to a region on the shaft proximal to the deflector 220. For illustrative purposes, the deflector 220 allows the basket to pivot about a pivot axis that is generally perpendicular to the deflector plane 206. As the basket 232 moves off-axis, it moves in a deflection direction F, e.g., toward a treatment site. As the deflected basket moves toward axis A, it returns to axis A in the opposite direction B. When the basket 232 is on-axis, axis A and basket axis X are parallel or collinear. For example, the shaft 202 may include a pull wire (not shown) mechanically coupled to the distal region 204, such as via a ring around the shaft, and mechanically coupled to the proximal end of the catheter, such as a handle, that can be actuated by a clinician to move the basket 232 off-axis. Tensioning the pull wire deflects the electrode assembly off-axis in a deflection direction F within the deflection plane, selectively directing the electrode assembly toward a treatment site.

[0055] In the expanded state, the electrode assembly 210 includes a first set 224 of splines 212 proximal to the deflection direction F and a second set 226 of splines 212 distal to the deflection direction F. In one example, the basket axis X lies in a bisector plane perpendicular to the deflection plane 206. The first set 224 of splines 212 is on a proximal side 240 of the bisector plane (shown in FIG. 2 as including the basket axis X) proximal to the deflection direction F. The second set 226 of splines 212 is on a distal side 242 of the bisector plane distal to the deflection direction F. An insulator 230 is disposed on the second set 226 of splines 212 to insulate the associated electrode 214. For example, insulators 230 are disposed on the ablation electrodes on the second set 226 of the plurality of splines 212, facing away from the cavity C opposite the deflection direction F. Insulators 230 are not disposed on the electrode surfaces facing toward the cavity C. For the electrodes 214 associated with the second set 226 of the plurality of splines 212, the electrode surfaces configured to face toward the cavity C are exposed. Additionally, insulators are not disposed on the mapping electrodes, and the mapping electrodes are exposed. For the ablation electrodes 214 associated with the second set 226 of the plurality of splines 212, the electrode surfaces configured to face away from the cavity C are insulated. Additionally, insulators 230 are not disposed on the associated electrodes 214 of the first set 224 of the plurality of electrodes.

[0056] In one example, the catheter 200 is operated in a monopolar mode to generate an electric field for electroporation. For example, the ablation electrodes on the first set 224 and second set 226 of splines 212 can be electrically connected to a single lead conductor extending the entire length of the shaft 202, or to a set of lead conductors within the shaft 202 configured to carry the same electrical signal to generate the electric field. The ablation electrode on the electrode assembly 210 is configured as either an anode or a cathode. None of the electrodes in the electrode assembly is configured as the other of a cathode or anode. Instead, the other of anode or cathode is provided in the form of a pad dispersing electrode that is placed on the patient during electroporation. The electric field is formed between the active electrode of the electrode assembly and the pad dispersing electrode. Through application of insulator 230 onto the second set 226 of splines 212, the electrode assembly 210 emits an asymmetric electric field that focuses electroporation energy into cavity C and toward deflection direction F, rather than emitting the field symmetrically in all directions radially from basket axis X. The lateral field emission corresponds to the deflection plane 206, and the electric field is directed toward the treatment tissue.

[0057] 3A-3E illustrate a few examples of many features of catheter 200. The examples in FIGS. 3A-3E are presented as schematic cross-sectional views that may represent catheter 200 as viewed along line 3-3 in FIG. 2. For example, FIGS. 3A-3E illustrate deflection plane 206, basket axis X within deflection plane 206, bisecting plane 244 that contains basket axis X and is perpendicular to deflection plane 206, deflection direction F, cavity C, and counter direction B.

[0058] 3A shows an exemplary electrode assembly 310A in an expanded state, including a first set 324A of splines 312A proximal to the deflection direction F and a second set 326A of splines 312A distal to the deflection direction F. While one spline from each set 324A, 326A is shown in this example, the first set 324A may include one or more splines, and the second set 326A may include one or more splines. In this example, a ring electrode 302 is associated with each spline 312A. For example, each spline 312A may include multiple longitudinally spaced ring electrodes, and at least one electrode from each spline may be used for ablation, such as ring electrode 302a associated with the first set of splines 324A and ring electrode 302b associated with the second set of splines 326A. The ring electrode 302a associated with the first set of splines 324A includes a portion of a surface 304a facing the deflection direction F and a portion of a surface 304b facing the cavity C. The ring electrode 302b associated with the second set of splines 326A includes a portion of a surface 304c facing the cavity C and a portion of a surface 304d facing the opposite direction B. An insulator 330A is disposed on the second set 326A of the plurality of splines 312A to insulate the associated ring electrode 302b. For example, the insulator 330A is disposed on the second set 326A of the plurality of splines 312A opposite the deflection direction F, and the insulator 330A is provided on the surface 304d of the ring electrode 302b. The insulator 330A is not disposed on the associated electrode 314A of the first set 324A of the plurality of electrodes. Additionally, insulator 330A is not disposed on electrode surfaces facing cavity C, such as surface 304c of ring electrode 302b.

[0059] 3B shows an exemplary electrode assembly 310B in an expanded state, including a first set 324B of splines 312B proximal to the deflection direction F and a second set 326B of splines 312B distal to the deflection direction F. While one spline from each set 324B, 326B is shown in this example, the first set 324B may include one or more splines, and the second set 326B may include one or more splines. In this example, a plate electrode 306 is associated with each spline 312B. For example, each spline 312B is formed by a longitudinally extending plate electrode that can be used for ablation, such as plate electrode 306a associated with the first set of splines 324B and plate electrode 306b associated with the second set of splines 326B. The plate electrode 306a associated with the first set of splines 324B includes a surface 308a facing the deflection direction F and a surface 308b facing the cavity C. The plate electrode 306b associated with the second set of splines 326B includes a surface 308c facing the cavity C and a surface 308d facing the opposite direction B. An insulator 330B is disposed on the second set 326B of the plurality of splines 312B to insulate the associated plate electrode 306b. For example, the insulator 330B is disposed on the second set 326B of the plurality of splines 312B opposite the deflection direction F, and the insulator 330B is provided on the surface 308d of the plate electrode 306b. The insulator 330B is not disposed on the associated electrode 314B of the first set of electrodes 324B. Furthermore, the insulator 330B is not disposed on the electrode surfaces facing the cavity C, such as the surface 308c of the plate electrode 308b.

[0060] 3C shows an exemplary electrode assembly 310C in an expanded state, including a first set 324C of splines 312C proximal to the deflection direction F and a second set 326C of splines 312C distal to the deflection direction F. While one spline from each set 324C, 326C is shown in this example, the first set 324C may include one or more splines, and the second set 326C may include one or more splines. In this example, a plate electrode 352 is associated with each spline 312C. For example, each spline 312C may include a resilient support member 354 having one plate electrode or multiple longitudinally spaced plate electrodes disposed thereon, and at least one electrode from each spline may be used for ablation, such as plate electrode 352a associated with the first set of splines 324C and plate electrode 352b associated with the second set of splines 326C. Plate electrode 352a associated with the first set of splines 324C includes a surface 356a facing the deflection direction F and a surface 356b facing the cavity C connected to support member 354a. Plate electrode 352b associated with the second set of splines 326C includes a surface 356c facing the cavity C connected to support member 354b and a surface 356d facing the opposite direction B. An insulator 330C is disposed on the second set 326C of the plurality of splines 312C to insulate the associated plate electrode 352b. For example, the insulator 330C is disposed on the second set 326C of the plurality of splines 312C opposite the deflection direction F, and the insulator 330C is provided on the surface 356d of the plate electrode 352b. The insulator 330C is not disposed on the associated electrode 314C of the first set 324C of the plurality of electrodes.

[0061] 3D shows an exemplary electrode assembly 310D in an expanded state, including a first set 324D of splines 312D proximal to the deflection direction F and a second set 326D of splines 312D distal to the deflection direction F. While one spline from each set 324D, 326D is shown in this example, the first set 324D may include one or more splines, and the second set 326D may include one or more splines. In this example, a plate electrode 372 is associated with each spline 312D. For example, each spline 312D may include a resilient support member 374 having one plate electrode or multiple longitudinally spaced plate electrodes disposed thereon, and at least one electrode from each spline may be used for ablation, such as plate electrode 372a associated with the first set of splines 324D and plate electrode 372b associated with the second set of splines 326D. Plate electrode 372a is disposed on support member 374a. Plate electrode 372a includes an aperture 380a, and mapping electrode 382a is disposed on first support member 374a. Plate electrode 372b is disposed on support member 374b. Plate electrode 372b includes an aperture 380b, and mapping electrode 382b is disposed on first support member 374b.

[0062] 4 shows a top view of a portion of a first set of splines 324D with mapping electrodes 382a disposed on support member 374a within apertures 380a of plate electrode 372a. Plate electrode 372a may include a plurality of longitudinally spaced apertures, such as aperture 380a, with a mapping electrode (e.g., mapping electrode 382a) disposed within each aperture for a plurality of longitudinally spaced mapping electrodes along the length of spline 324D for each spline 312D in the basket.

[0063] 3D also shows that the plate electrode 372a associated with the first set of splines 324D includes a surface 376a facing the deflection direction F and a surface 376b facing the cavity C connected to the support member 374a. The plate electrode 372b associated with the second set of splines 326D includes a surface 376c facing the cavity C connected to the support member 374b and a surface 376d facing the opposite direction B. An insulator 330D is disposed on the second set 326D of the plurality of splines 312D to insulate the associated plate electrode 372b. For example, the insulator 330D is disposed on the second set 326D of the plurality of splines 312D opposite the deflection direction F, with the insulator 330D provided on the surface 376d of the plate electrode 372b. The insulator 330D is not disposed on the associated electrode 314D of the first set 324D of the plurality of electrodes. Additionally, insulator 330D is not disposed on mapping electrodes such as mapping electrode 382b.

[0064] 3E shows an exemplary electrode assembly 310E in an expanded state, including a first set 324E of splines 312E proximal to the deflection direction F and a second set 326E of splines 312E distal to the deflection direction F. While one spline from each set 324E, 326E is shown in this example, the first set 324E may include one or more splines, and the second set 326E may include one or more splines. In this example, a plate electrode 396 is associated with each spline 312E. For example, each spline 312E is formed by a longitudinally extending plate electrode that can be used for ablation, such as plate electrode 396a associated with spline 326B of the first set and plate electrode 396b associated with spline 324E of the second set. The plate electrode 396a associated with the first set of splines 326E includes a surface 398a facing the deflection direction F and a surface 398b facing the cavity C. The plate electrode 396b associated with the second set of splines 324E includes a surface 398c facing the cavity C and a surface 398d facing the opposite direction B. An insulator 330E is disposed on the second set 326E of the plurality of splines 312E to insulate the associated plate electrode 396b. For example, the insulator 330E is disposed on the second set 326E of the plurality of splines 312E opposite the deflection direction F, with the insulator 330E provided on the surface 398d of the plate electrode 396b. The insulator 330E is also disposed on the associated electrode 314E (e.g., the surface 396b of the plate electrode 398a) of the first set 324E of the plurality of electrodes.

[0065] In constructing the electroporation catheter 200 of FIG. 2, an elongate shaft 202 is provided having a distal region 204 and a deflection plane 206. The elongate shaft 202 defines a longitudinal axis A. The elongate shaft 202 includes a lead conductor. An electrode assembly 210 is operably coupled to the distal region 204 and configured to generate an electric field. The electrode assembly 210 is configured to include a plurality of splines 212, each of which supports an associated electrode 214. In one example, each spline supports an associated ablation electrode, and each ablation electrode is electrically connected to the lead conductor to receive the same electrical signal. The splines 212 are movable between a contracted state and an expanded state. A deflector 220 is constructed or configured in the distal region 204. The deflector 220 is actuable in the expanded state to deflect the electrode assembly 210 from the axis A toward a deflection direction F in the deflection plane 206. For example, the deflector 220 is coupled to the shaft 202, and the axis A is determined proximal to the deflector 220. In the expanded state, the electrode assembly 210 includes a first set 224 of splines 212 proximal to the deflection direction F and a second set 226 of splines 212 distal to the deflection direction F. An insulator 230 is disposed, such as by being deposited, on the second set 226 of splines 212 to insulate the associated electrodes 214. For example, the insulator 230 is deposited on the second set 226 of splines 212 opposite the deflection direction F. The insulator 230 is not deposited on the associated electrodes 214 of the first set 224 of electrodes.

[0066] FIG. 5 illustrates a portion of an exemplary electroporation catheter 500 for use with electrophysiology system 50 and constructed in accordance with electroporation catheter 200. The exemplary electroporation catheter 500 includes an elongate tubular shaft 502 having a distal region 504 within a deflection plane 506 (shown in FIG. 6). The distal region 504 is configured to be deployed near a target tissue (e.g., within a cardiac chamber of a patient). The elongate shaft 502 defines a longitudinal axis AA. The longitudinal axis AA is depicted as a line passing through the center of gravity of a cross-section of the shaft 502. An electrode assembly 510 is operably coupled to the distal region 504 and is configured to generate an electric field. In one example, the electric field causes irreversible electroporation in selected cardiac tissue. The electrode assembly 510 includes a plurality of ablation electrodes 514 (514a, 514b, 514c, 514d, 514e, 514f, as shown) configured as a plurality of splines 512 (512a, 512b, 512c, 512d, 512e, 512f, as shown). Each ablation electrode 514 includes an outer conductive surface 516 and an opposing inner conductive surface 518. The inner conductive surface 518 faces toward the cavity CC, and the outer conductive surface 516 faces away from the cavity CC. The ablation electrodes 514 are configured to receive a pulsed electrical signal or waveform from the electroporation console 130 to generate a pulsed electric field sufficient to ablate target tissue by irreversible electroporation. Each spline 512 supports an associated mapping electrode 522. For example, a plurality of associated mapping electrodes 522 are mounted on the outer conductive surface 516 of each ablation electrode 514 and are longitudinally spaced apart along each spline 512. Insulation may be disposed between the mapping electrode 522 and the associated ablation electrode 514. The mapping electrodes 522 are configured to, among other things, sense cardiac electrical signals, locate the electrode assembly 510 within the patient's anatomy, such as via the EAM system 70, and determine proximity to target tissue within the anatomy.The mapping electrodes 522 in the electrode assembly 510 may be electrically connected to one or more lead conductors extending along the length of the shaft 502 configured to transmit electrical signals received at the mapping electrodes.

[0067] The splines 512 are transitionable between a contracted state and an expanded state. A deflector 520 resides in the distal region 504. The deflector 520 is actuable in the expanded state to deflect the electrode assembly 510 off axis AA toward a deflection direction FF in the deflection plane 506. For example, the deflector 520 is coupled to the shaft 502, and the axis AA is determined proximal to the deflector 520. In the expanded state, the electrode assembly 510 includes a first set 524 of a plurality of ablation electrodes 514 proximal to the deflection direction FF and a second set 526 of ablation electrodes distal to the deflection direction FF. For example, the first set 524 may include three ablation electrodes 524a, 524b, and 524c, one on each of the splines 512a, 512b, and 512c. In the example, the second set 526 may include three ablation electrodes 526a, 526b, 526c, one on each of the splines 512d, 512e, 512f, as shown, although other configurations are contemplated, such as configurations other than six splines 512 or multiple ablation electrodes per spline. Insulators 530 are disposed on the second set 526 of the multiple ablation electrodes 514, covering the outer conductive surfaces 516 of the associated ablation electrodes 514 with the insulator and leaving the associated mapping electrodes 522 on the insulated splines 512d, 512e, 512f exposed and uncovered. In one example, the insulators 530 are not disposed on the inner conductive surfaces 518 of the second set 526 of the ablation electrodes 514. In these examples, the insulators 530 are not disposed on the first set 524 of the ablation electrodes 514. In another example, the insulator 530 is disposed on the inner surface 518 of each of the first set 524 of ablation electrodes 514 .

[0068] In the illustrated example, the splines 512 form a basket 532 coupled to the shaft 502. The basket 532 may include an expanded length, an expanded diameter, and a particular outer shape in an expanded state. The length of the basket 532 may be determined based on the longitudinal distance of the splines 512 from the proximal end to the distal end along the basket axis XX. The diameter of the basket 532 may be determined based on the maximum distance between opposing splines 512 in a direction generally perpendicular to the basket axis XX. In the expanded state, the splines 512 are spaced apart from one another to form a cavity CC within the basket 532. In this example, the splines 512 are constructed from a conductive, flexible, elastic material such that the catheter 500 may be capable of transitioning to a contracted state. In one example, a deployment sheath is positioned over the splines 512, and the catheter 500 is placed in the contracted state while the catheter 500 is in a non-operational mode. When the basket 532 is extended from the deployment sheath, or the deployment sheath is withdrawn from the basket 532, the basket can assume an expanded state and be deployed in an operational mode.

[0069] The deflector 520 allows the basket 532 to deflect or move off axis AA, such as toward a treatment site in the deflection plane 506. In one example, the deflector 520 allows the basket 532 to pivot or bend about a basket axis XX in the deflection plane 506 relative to a region on the shaft proximal to the deflector 520. As the basket 532 moves off axis, it moves in a deflection direction FF, e.g., toward a treatment site. When the deflected basket 532 moves toward axis AA, it returns to axis AA in the opposite direction BB. When the basket 532 is on axis, the axis AA and the basket axis XX are parallel or collinear.

[0070] In the expanded state, the electrode assembly 510 includes a first set 524 of ablation electrodes 514 of the plurality of splines 512 proximal to the deflection direction FF and a second set 526 of ablation electrodes 514 of the plurality of splines 512 distal to the deflection direction FF. In one example, the basket axis XX lies in a bisecting plane 544 perpendicular to the deflection plane 506. The first set 524 of ablation electrodes 514 of the plurality of splines 512 is proximal 540 of the proximal bisecting plane 534 of the deflection direction FF. The second set 526 of the plurality of electrodes 514 of the plurality of splines 512 is distal 542 of the distal bisecting plane 544 of the deflection direction FF (shown in FIG. 6 ).

[0071] In one example, the catheter 500 is operated in a monopolar mode to generate an electric field for electroporation. For example, the ablation electrode 514 in the electrode assembly 510 can be electrically connected to a single lead conductor extending the entire length of the shaft 502, or to a set of lead conductors in the shaft 502 configured to carry the same electrical signal to generate the electric field. The ablation electrode 514 on the electrode assembly 510 is configured as either an anode or a cathode. None of the electrodes in the electrode assembly 510 is configured as the other of a cathode or anode. Instead, the other of a cathode or anode is provided in the form of a pad dispersing electrode that is placed on the patient during electroporation. The electric field is formed between the active ablation electrode 514 and the pad dispersing electrode of the electrode assembly. Through application of insulator 530 onto the second set 526 of ablation electrodes 514 of the plurality of splines 512, the electrode assembly 510 emits an asymmetric electric field that focuses electroporation energy into cavity CC and toward deflection direction FF, rather than emitting the electric field symmetrically in all directions radially from basket axis XX. The lateral field emission corresponds to the deflection plane 506, and the electric field is directed toward the treatment tissue.

[0072] 6 shows a front cross-sectional view of the basket 532 of the catheter 500 in the expanded state. In the expanded state, the electrode assembly 510 includes a first set 524 of ablation electrodes 514 of the plurality of splines 512 proximal to the deflection direction FF and a second set 526 of ablation electrodes 514 of the plurality of splines 212 distal to the deflection direction FF. In one example, the basket axis XX lies within a bisecting plane 534 perpendicular to the deflection plane 506. The first set 524 of ablation electrodes 514 of the plurality of splines 512 is proximal to the bisecting plane 534 of the deflection direction FF. The second set 526 of electrodes 514 of the plurality of splines 512 is distal to the bisecting plane 542 of the distal bisecting plane 544 of the deflection direction FF. The first set 524 includes three ablation electrodes 524a, 524b, 524c, one on each of the splines 512a, 512b, 512c. The second set 526 may include three ablation electrodes 526a, 526b, 526c, one on each of the splines 512d, 512e, 512f, as shown, although other configurations are envisioned, such as configurations other than six splines 512 or multiple ablation electrodes per spline. Insulators 530 are disposed on the second set 526 of ablation electrodes 514, covering the outer conductive surfaces 516 of the associated ablation electrodes 514 with insulation and leaving the associated mapping electrodes 522 on the insulated splines 512d, 512e, 512f exposed. In one example, insulator 530 is not disposed on the inner conductive surface 518 of the second set 526 of ablation electrodes 514. In these examples, insulator 530 is not disposed on the first set 524 of ablation electrodes 514. In another example, insulator 530 is disposed on the inner surface 518 of each of the first set 524 of ablation electrodes 514.

[0073] Various modifications and additions may be made to the exemplary embodiments described without departing from the scope of the present disclosure. For example, while the above-described embodiments refer to particular features, the scope of the present invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the claims, together with all equivalents thereof.

Claims

1. 1. An electroporation catheter for ablation of cardiac tissue, comprising: an elongate shaft having a distal region and a deflection flat, the elongate shaft defining an axis; an electrode assembly operably coupled to the distal region and configured to generate an electric field, the electrode assembly having a plurality of splines, each spline supporting an associated ablation electrode, the plurality of splines being transitionable between a contracted state and an expanded state; a deflector in the distal region, the deflector operable in the expanded state to deflect the electrode assembly off-axis toward a deflection direction in the deflection plane, the electrode assembly including, in the expanded state, a first set of the plurality of splines proximal to the deflection direction and a second set of the plurality of splines distal to the deflection direction; an insulator disposed on the second set of the plurality of splines to insulate at least a portion of the associated ablation electrode.

2. 2. The electroporation catheter of claim 1, wherein the plurality of splines form a basket defining a cavity in the expanded state, and the insulator directs an electric field from each ablation electrode associated with the second set of the plurality of splines toward the cavity.

3. The electroporation catheter of claim 2 , wherein the basket is guidable toward the treatment site by the deflector.

4. 4. The electroporation catheter of claim 1, wherein the electrode assembly is configured as one of a cathode and an anode to generate an electric field in a monopolar mode.

5. The electroporation catheter of claim 4 , wherein the shaft includes a lead conductor, and each of the plurality of associated ablation electrodes is electrically connected to the lead conductor.

6. 6. The electroporation catheter of claim 1, wherein each ablation electrode associated with the second set of splines includes a surface facing the deflection direction and a surface facing opposite the deflection direction, and the insulator is disposed on the surface facing opposite the deflection direction.

7. 7. The electroporation catheter of claim 1, wherein each ablation electrode associated with each of the plurality of splines includes a surface facing the deflection direction and a surface facing the deflection direction, and the insulator is disposed on the surface facing away from the deflection direction.

8. 8. The electroporation catheter of claim 1, wherein each spline is formed from the associated ablation electrode.

9. The electroporation catheter of claim 1 , wherein the electrode assembly further comprises a mapping electrode.

10. The electroporation catheter of claim 1 , wherein each spline further comprises a mapping electrode.

11. 11. The electroporation catheter of claim 10, wherein each spline includes a longitudinal length, and each spline includes a plurality of mapping electrodes disposed along the longitudinal length.

12. 12. The electroporation catheter of claim 9, wherein the mapping electrodes are not covered by the insulator.

13. The electroporation catheter of claim 1 , wherein each spline includes a resilient support member coupled to an electrode.

14. The electroporation catheter of claim 13 , wherein each spline further comprises a plurality of exposed mapping electrodes.

15. 10. The electroporation catheter of claim 1, wherein each spline supports one associated elongated ablation electrode.

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