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] The present disclosure relates to medical systems and methods for facilitating ablation of patient tissue. More specifically, the present disclosure relates to medical systems and methods for facilitating tissue ablation by electroporation. BACKGROUND ART

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

[0003] Another ablation technique uses electroporation. In electroporation, or electro-permeabilization, an electric field is applied to cells to increase the permeability of the cell membrane. Electroporation can be reversible or irreversible depending on the strength 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 before cell healing and recovery. Tissue recovery can occur over minutes, hours, or days after the ablation is complete. If electroporation is irreversible, the affected cells die, for example, through a form of cell death (e.g., programmed cell death via apoptosis, or traumatic cell death via necrosis).

[0004] Irreversible electroporation can be used as a non-thermal ablation technique. In irreversible electroporation, a short-duration high-voltage pulse train is used to generate an electric field strong enough to kill cells. In cardiac tissue ablation, irreversible electroporation may be a relatively safe and effective alternative to the indiscriminate cell death of thermal ablation techniques such as RF ablation and cryoablation. While irreversible electroporation can be used to kill target tissues such as myocardial tissue, it can also be used to kill target tissues by selecting electric field strengths and durations that are not effective in permanently killing other cells or tissues such as non-target myocardial tissue, red blood cells, vascular smooth muscle tissue, endothelial tissue, and nerve cells. [Overview of the project]

[0005] Example 1 describes an electroporation catheter for cardiac tissue ablation. The electroporation catheter comprises a long shaft, an electrode assembly, a deflector, and an insulator. The long shaft comprises a distal region and a deflection plane, and the long shaft defines an axis. The electrode assembly is operably connected to the distal region and configured to generate an electric field. The electrode assembly comprises several splines, each supporting the associated ablation electrode. The splines are transitionable between a contracted state and an expanded state. The deflector is located in the distal region. In the expanded state, the deflector is operable to deflect the electrode assembly off the axis and in the direction of deflection within the deflection plane. In the expanded state, the electrode assembly comprises a first set of splines proximal to the direction of deflection and a second set of splines distal to the direction of deflection. The insulator is positioned 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, multiple splines form a basket that defines a cavity in the expanded state, and an insulator directs the electric field from each ablation electrode associated with a second set of multiple splines into the cavity.

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

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

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

[0010] In Example 7, in any of the electroporation catheters of Examples 1 to 6, each ablation electrode associated with each spline includes a surface facing the direction of deflection and another surface facing the direction of deflection, and the insulator is placed on the surface facing the opposite direction of deflection.

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

[0012] In Example 10, in any of the electroporation catheters from Examples 1-8, each spline further includes a mapping electrode. In Example 11, in the electroporation catheter of Example 10, each spline includes a longitudinal length, and each spline includes multiple mapping electrodes arranged along the longitudinal length.

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

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

[0015] Example 16 describes an electroporation catheter for cardiac tissue ablation. The electroporation catheter comprises a long shaft, an electrode assembly, a deflector, and an insulator. The long shaft comprises a distal region and a deflection plane. The long shaft defines an axis. The electrode assembly is operably connected to the distal region and configured to generate an electric field. The electrode assembly comprises several splines, each spline supporting the associated ablation electrode. The splines are transitionable between a contracted state and an expanded state. The deflector is located in the distal region. In the expanded state, the deflector is operable to deflect the electrode assembly off the axis and in the direction of deflection within the deflection plane. In the expanded state, the electrode assembly comprises a first set of several splines proximal to the direction of deflection and a second set of several splines distal to the direction of deflection. The insulator is positioned on the second set of several splines to insulate at least a portion of the associated ablation electrode.

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

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

[0018] In Example 20, in the electroporation catheter of Example 19, 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 a second set of multiple splines includes a surface facing the direction of deflection and a surface facing the opposite direction of deflection, and the insulator is placed on the surface facing the opposite direction of deflection.

[0020] In Example 22, in the electroporation catheter of Example 21, each ablation electrode associated with each of the multiple splines includes a surface facing the direction of deflection and another surface facing the direction of deflection, and the insulator is placed on the surface facing the opposite direction of deflection.

[0021] In Example 23, the ablation electrode associated with the first set of multiple splines is exposed in the electroporation catheter of Example 16. In Example 24, in the electroporation catheter of Example 16, each spline further includes a mapping electrode.

[0022] In Example 25, in the electroporation catheter of Example 24, each spline includes multiple exposed mapping electrodes positioned along the spline. Example 26 describes an electroporation catheter for cardiac tissue ablation. The electroporation catheter comprises an elongated shaft, an electrode assembly, a deflector, and an insulator. The elongated shaft comprises a distal region and a deflection plane. The elongated shaft defines an axis. The electrode assembly is operably connected to the distal region and configured to generate an electric field. The electrode assembly comprises a plurality of elongated ablation electrodes configured as a plurality of splines. Each ablation electrode comprises 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 located in the distal region. In the expanded state, the deflector is operable to deflect the electrode assembly off the axis and toward the deflection direction in the deflection plane. In the expanded state, the electrode assembly comprises a first set of a plurality of splines on the proximal side of the deflection direction and a second set of a plurality of splines on the distal side of the deflection direction. The insulator is positioned on a second set of splines such that it insulates at least a portion of the outer conductive surface and exposes the mapping electrodes.

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

[0024] In Example 28, in the electroporation catheter of Example 27, the insulator placed on the second set of splines does not insulate the inner conductive surface. In Example 29, in the electroporation catheter of Example 28, an insulator is further placed on the first set of splines such that it insulates the inner conductive surfaces of the first set of splines but does not insulate the outer conductive surfaces of the first set of splines.

[0025] In Example 30, in the electroporation catheter of Example 26, the shaft includes lead conductors, and each of the ablation electrodes is electrically connected to the lead conductors. In Example 31, a method for manufacturing an electroporation catheter for ablating cardiac tissue is provided. An elongated shaft having a distal region and a deflection plane is provided. The elongated 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, and each spline supports an associated ablation electrode. The splines are transitionable between a contracted state and an expanded state. A deflector is disposed in the distal region. The deflector is operable in the expanded state to deflect the electrode assembly off the axis toward a deflection direction within the deflection plane. In the expanded state, the electrode assembly includes a first set of the plurality of splines on the proximal side in the deflection direction, and a second set of the plurality of splines on the distal side in the deflection direction. An insulator is deposited on the second set of the plurality of splines so as to insulate at least a portion of the associated electrodes.

[0026] In Example 32, the method of Example 31, wherein providing the shaft includes providing lead conductors within the shaft, and further comprising electrically connecting each of the plurality of associated ablation electrodes to the lead conductors.

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

[0028] In Example 35, the method of Example 31, further comprising attaching a plurality of mapping electrodes to each spline, wherein the insulator is not deposited on the plurality of mapping electrodes. While several embodiments are disclosed, further embodiments of the present invention will become apparent to those skilled in the art from the following detailed description illustrating and explaining exemplary embodiments of the invention. Accordingly, the drawings and detailed description should be considered illustrative and not limiting. [Brief explanation of the drawing]

[0029] [Figure 1] This outlines exemplary clinical settings for treating patients and treating patients' hearts using electrophysiological systems according to embodiments of the subject matter of this disclosure. [Figure 2] Figure 1 is a schematic diagram showing an exemplary catheter that may be used in an exemplary electrophysiological system. [Figure 3A] Figure 2 is a schematic cross-sectional front view of a first exemplary electrode assembly that may be used in the exemplary catheter. [Figure 3B] Figure 2 is a schematic cross-sectional front view of a second exemplary electrode assembly that may be used in the exemplary catheter. [Figure 3C] This is a schematic front cross-sectional view of a third exemplary electrode assembly that may be used in the exemplary catheter shown in Figure 2. [Figure 3D] Figure 2 is a schematic cross-sectional front view of a fourth exemplary electrode assembly that may be used in the exemplary catheter. [Figure 3E] Figure 2 is a schematic cross-sectional front view of a fifth exemplary electrode assembly that may be used in the exemplary catheter. [Figure 4] Figure 3D is a top view of a portion of a fourth exemplary electrode assembly. [Figure 5] Figure 2 is a perspective view of the distal portion of an exemplary spline catheter for use in the electrophysiological system shown in Figure 1, using the exemplary catheter shown in Figure 2. [Figure 6] Figure 5 is a schematic front cross-sectional view of a portion of the electrode assembly of an exemplary spline catheter. [Modes for carrying out the invention]

[0030] While the present invention can be adapted to various modifications and alternative forms, specific embodiments are shown in the drawings as examples and are described in detail below. However, the intention is not to limit the present invention to the specific embodiments described. Rather, the present invention is intended to encompass all modifications, equivalents, and alternative forms that fall within the scope of the invention as defined by the appended claims.

[0031] For the purpose of facilitating an understanding of the principles of this disclosure, examples shown in the drawings described below will be referenced. The exemplary examples disclosed herein are not intended to be exhaustive or to limit this disclosure to the exact forms disclosed for carrying out the inventions described below. Rather, these exemplary embodiments are selected and described so that those skilled in the art can use their teachings. It is not beyond the scope of this disclosure to use multiple (e.g., all) features across all examples. Accordingly, no drawing should be construed as having any dependencies or requirements relating to any single component or combination of components shown. In addition, various components shown in the drawings may, in some examples, be integrated with various other components shown (or not shown), all of which are considered to be within the scope of this disclosure.

[0032] As applied to electrophysiological systems, irreversible electroporation uses high voltage, short pulses to kill cells such as cardiomyocytes by apoptosis while preserving other adjacent tissues, including esophageal vascular smooth muscle and endothelium. Irreversible electroporation therapy can be performed in multiple treatment sections. Treatment sections, which may have durations in the millisecond range, may 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 transwall damage. Such pulsed electric field ablation generates an electric field with a generally spherical cross-section around a generally point-shaped electrode, or an electric field with a generally circular cross-section around a generally linear electrode, largely unrelated to tissue or blood within the heart. Such electric fields may include the possibility of causing secondary damage to adjacent areas on the blood pool side of the electrode or opposite to the target tissue. In contrast, RF ablation can be concentrated on areas in direct contact with the electrode.

[0033] Electroporation devices used for ablation and cardiac mapping, such as mapping and ablation catheters, are typically larger than many RF ablation catheters. For example, the working end of a mapping and ablation catheter can have a diameter of 7mm to 15mm or more. Such catheters often generate relatively large electric fields for ablation, which increases the likelihood of causing secondary damage to areas opposite to the myocardial target tissue.

[0034] Figure 1 illustrates an exemplary clinical environment 10 for treating a patient 20 (for example, to treat the heart 30 of patient 20) using the electrophysiological system 50 according to this disclosure. The electrophysiological 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 (e.g., imaging equipment 94 (represented by a C-arm)) and various controller elements (e.g., foot controller 96) configured to allow the operator to control various aspects of the electrophysiological system 50. The clinical environment 10 may have other components and configurations not shown in Figure 1.

[0035] 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 within the tissue, for example, so that the tissue is unable to transmit electrical signals. The electroporation catheter system 60 is also configured to use the electroporation catheter 105 to generate an electric field and create and present an electroanatomical map of the patient's heart on the display 92 to assist the clinician in planning irreversible electroporation ablation using the electroporation catheter 105 before delivering ablation electric field energy. In the embodiment, the electroporation catheter system 60 is configured to generate an electric field based on the characteristics of the electroporation catheter 105 and the location of the electroporation catheter 105 within the patient 20 (e.g., within the patient's heart 30). The electroporation catheter system 60 is configured to generate a graphic representation of the electroporation catheter and electroanatomical map based on the characteristics of the electroporation catheter 105, the location of the electroporation catheter 105 within the patient 20 (e.g., within the patient 20's heart 30), and the characteristics of the tissue surrounding the catheter 105 (e.g., the measured impedance of the tissue). In one example, the electroporation catheter 105 is a mapping and ablation catheter that works in conjunction with the EAM system 70 to deploy in a mapping procedure, deliver ablation 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 can be deployed to a specific target site within the patient's heart 30. Access to the patient's heart can be made through a blood vessel (e.g., a peripheral artery or vein). Once blood vessel access is obtained, the electroporation catheter 105 can be guided into the patient's heart (e.g., into a cardiac chamber).

[0037] An exemplary electroporation catheter 105 includes a long catheter shaft and a distal end region configured to deploy near a target tissue (e.g., within the patient's heart chambers). The shaft extends from an access point in the patient to the target tissue and generally defines the longitudinal axis of the electroporation catheter 105. The distal end region may include a basket, balloon, spline, configured tip, or other electrode deployment mechanism connected to the shaft. The electrode deployment mechanism includes an electrode assembly or electrode array comprising electrodes. For example, an 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, the electrodes on the electrode deployment mechanism. For example, the electrode deployment mechanism includes multiple splines configured to form a basket, and at least some of the multiple electrodes are positioned on the splines.

[0038] The electroporation catheter 105 can be configured in multiple forms. For example, when the distal end region of the catheter 105 is within the sheath as a catheter assembly (for example, to move into the cardiac chambers of the patient's heart), the electrode deployment mechanism and electrode assembly are in a contracted state so as to fit within the sheath. When the catheter reaches the target location, for example, within the cardiac chambers of the heart, the sheath is withdrawn from the distal region of the catheter 105 (or the shaft catheter extends beyond the sheath), and the electrode deployment mechanism and electrode assembly may be in an expanded state. The electrode assembly has a contracted shape when the catheter 105 is in a contracted state and an expanded shape when the catheter 105 is in an expanded state. In some examples, the electrode assembly has two or more states.

[0039] In one example, multiple electrodes may be formed from a biocompatible material with a conductive solid surface and are 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 of the spaced-apart multiple 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 conceivable. 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, for example, directly or via an intermediate electrical conductor such as cable wiring, to a plug in the proximal region of the electroporation catheter 105 (e.g., a plug configured to be mechanically and electrically connectable to an electroporation console 130).

[0040] The electroporation console 130 includes a controller (e.g., one or more controllers, processors, or computers) which executes instructions or code (e.g., processor-executable instructions) from a non-temporary computer-readable medium (e.g., a memory device or memory) to control or execute aspects of the electroporation catheter system 60. In one example, the electroporation console 130 is configured to supply electrical signals (e.g., multiple simultaneous or time-staggered electrical signals) to an electroporation catheter 105 electrically connected along lead conductors leading to spaced electrodes. The spaced electrodes are configured to generate a selected electric field near the target tissue for 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 will receive them. By selecting a first electrode or a first group of electrodes as the anode and a different second electrode or a second 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) supplied to the electrodes from the electroporation console 130. The console 130 supplies electrical pulses of different lengths and magnitudes to the electrodes on the catheter 105. The electrical pulses can be supplied as a continuous pulse stream or as a series of separate pulses. Pulse parameters of interest include the number of pulses, the duty cycle of the pulses, the interval between pulse trains, the voltage or magnitude of the pulses (including the peak voltage), and the duration of the voltage. For example, the console 130 can select two or more electrodes in an electrode assembly and supply 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 single-phase and bi-phase waveforms. While not limited to any particular theory, electric field strengths in the range of approximately 200–250 volts / cm (V / cm) with pulse durations on a microsecond scale have been demonstrated to provide reversible electroporation in cardiac tissue. Electric field strengths of approximately 400 V / cm have been demonstrated to provide irreversible electroporation in cardiac tissue of interest (e.g., target myocardial tissue and endocardial tissue) with demonstrable preservation of red blood cells, vascular smooth muscle tissue, endothelial tissue, nerves, and other non-target nearby tissues.

[0043] Furthermore, the electrode assembly on the catheter 105 may operate in a selected mode, such as unipolar or bipolar mode. During unipolar operation of the catheter 105, an electrode, electrode group, or the entire electrode assembly is configured as either an anode or a cathode. None of the electrodes within the electrode assembly 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-dispersed electrode, which is placed on the patient during electroporation, typically on the back, buttocks, or other appropriate anatomical site. An electric field is formed between the activated electrode of the electrode assembly and the pad-dispersed electrode. In an alternative configuration, a return electrode, such as multiple return electrodes, may be placed on the shaft of the catheter. An electric field is formed between the activated electrode of the electrode assembly and the return electrode on the shaft of the catheter 105. During bipolar operation of the catheter 105, to generate an electric field, a first set of one or more electrodes in the electrode assembly is configured as an anode, and a second set of one or more electrodes in the electrode assembly is configured as a cathode. In this example, pad-dispersed electrodes are not used, and the electric field does not spread throughout the patient's body, but rather through localized areas of tissue near the electrode assembly.

[0044] In some examples, the 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 for mapping purposes. In some configurations, the mapping electrode is configured to collect electrical signals used to generate an electroanatomical map, in which a detailed three-dimensional geometric anatomical map or representation of the cardiac chambers, as well as an electroanatomical map in which the cardiac electrical activity of interest is superimposed on the geometric anatomical map, by an operablely coupled EAM system 70, and to display by an operablely coupled display 92. In some examples, the electrodes can operate as ablation electrodes in the ablation mode of the electrophysiological 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 a 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 in the cardiac chambers of interest. In some examples, the electroanatomical map is generated after ablation to verify desired changes in the electrical activity of the excised tissue and cardiac chambers. Mapping electrodes can also be used to determine the position of catheter 105 in three-dimensional space within the body. For example, when an operator moves the distal end of catheter 105 within a cardiac 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 cardiac chamber. The anatomical map of the cardiac chamber can be used to assist in the navigation of catheter 105 without the use of ionizing radiation (e.g., fluoroscopy), and to tag the ablation site when the ablation is complete, to guide the ablation interval and assist the clinician in dissecting the anatomical structure of interest. In some examples, one electrode in the electrode assembly may be configured to perform ablation only, or one electrode in the electrode assembly may be configured to perform mapping only.

[0045] The EAM system 70 is configured to generate an electroanatomical map for display on the display 92. The EAM system 70 can track the positions of various components of the electroporation catheter system 60 and operate to generate high-fidelity three-dimensional anatomical and electroanatomical maps of the heart, including parts of the heart (e.g., chambers of interest or other structures of interest (e.g., sinoatrial node or atrioventricular node)). In one exemplary 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 also includes one or more controllers (e.g., a microprocessor or computer) that execute code from memory to control or perform functional aspects of the EAM system 70, and the memory may be part of one or more controllers, a microprocessor, a computer, or a memory device accessible via a computer network.

[0046] The EAM system 70 generates a localization field via the field generator 80 to form a localization volume around the heart 30, and a position sensor or sensing element on the device being tracked (e.g., a sensor on the electroporation catheter 105) generates an output that can be processed by the mapping and navigation controller 90 to track the position of the sensor within the localization volume, and thus the position of the corresponding device. In the illustrated example, device tracking is performed using a magnetic tracking technique, the field generator 80 is a magnetic field generator that generates a magnetic field that forms the localization volume, and the position sensor on the device being tracked is a magnetic field sensor.

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

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

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

[0050] The electroporation catheter system 60 can be combined with or integrated with the EAM system 70 to enable the visualization of a graphical representation of the electric field that may be generated by the electroporation catheter 105 on an electroanatomical map of the patient's heart. The integrated system may include features that improve the efficiency of the clinical workflow, including providing clinicians with an improved visual representation of the ablation lesion of the portion of the patient's heart formed through irreversible electroporation. The integrated system may include generating a graphical representation of the electric field that may be generated by the electroporation catheter 105, generating an anatomical map including an electroanatomical map, and displaying information regarding the location and intensity of the electric field that may be generated by the electroporation catheter 105.

[0051] The illustration of the electrophysiological system 50 shown in Figure 1 is intended to be illustrative or a general overview of the various components of the system 50, and is not intended to mean that this 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 electrophysiological system 50.

[0052] Figure 2 shows an exemplary electroporation catheter 200 for cardiac tissue ablation, which is an example of catheter 105 and may be used in conjunction with an electrophysiological system 50. The exemplary electroporation catheter 200 includes an elongated shaft 202 having a distal region 204 and a deflection plane 206. The distal region 204 is configured to unfold near the target tissue (e.g., within the patient's heart chambers). The elongated shaft 202 defines a longitudinal axis A. The longitudinal axis A is shown as a straight line passing through the centroid of the cross-section of the shaft 202. An electrode assembly 210 is operably connected to the distal region 204 and configured to generate an electric field. In one example, the electric field causes irreversible electroporation in the selected cardiac tissue. The electrode assembly 210 includes a plurality of splines 212, each spline of the plurality of splines 212 supporting an associated electrode 214. In one example, each spline supports an associated ablation electrode. For example, each spline supports multiple associated ablation electrodes. The splines 212 are transitionable between a contracted state and an expanded state. The deflector 220 is located within the distal region 204. In the expanded state, the deflector 220 is operable to deflect the electrode assembly 210 away from axis A and toward a deflection direction F in the deflection plane 206. For example, the deflector 220 is connected to a shaft 202, and axis A is determined on the proximal side of the deflector 220. In the expanded state, the electrode assembly 210 includes a first set 224 of multiple splines 212 located proximal to the deflection direction F, and a second set 226 of multiple splines 212 located 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. The insulator 230 is positioned on a second set 226 of multiple splines 212 so as to insulate at least a portion of the associated electrode 214. For example, the insulator 230 is positioned on the second set 226 of multiple splines 212 on the opposite side of the deflection direction F. The insulator 230 is not positioned on the associated electrode 214 of the first set 224 of multiple electrodes.

[0053] In the illustrated example, the splines 212 form a basket 232 connected to the shaft 202. In the expanded state, the basket 232 may include an expanded length L, an expanded diameter D, and a specific external shape. The length of the basket 232 (e.g., length L) 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 of the basket 232 (e.g., diameter D) may be determined based on the maximum distance between opposing splines 212 in a direction substantially perpendicular to the basket axis X. In the expanded state, the splines 212 are spaced apart from each other and form a cavity C within the basket 232. In this example, the splines 212 are constructed from flexible and elastic materials so that the catheter 200 may be able to transition 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, the catheter 200 is positioned with a deployment sheath covering the spline 212, and is kept in a retracted state while the catheter 200 is in non-operating mode. When the basket 232 extends from the deployment sheath or the deployment sheath is withdrawn from the basket 232, the basket takes an expanded state and can be deployed in operating mode.

[0054] The deflector 220 allows the basket 232 to deflect or move away from axis A, such as toward the treatment site in the deflection plane 206. In one example, the deflector 220 allows the basket 232 to pivot or bend in the deflection plane 206 with respect 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 approximately perpendicular to the deflector plane 206. When the basket 232 moves away from the axis, it moves in the deflection direction F, for example toward the treatment site. When the deflected basket moves toward axis A, the basket returns to axis A in the opposite direction B. When the basket 232 is on the axis, axis A and the basket axis X are parallel or collinear. For example, the shaft 202 may include a pull wire (not shown) mechanically connected to the distal region 204 via a ring around the shaft and to the proximal end of the catheter, such as a handle, allowing the clinician to operate the basket 232 to move off-axis. When tension is applied to the pull wire, the electrode assembly is deflected off-axis in the deflection direction F within the deflection plane, and the electrode assembly is selectively guided toward the treatment site.

[0055] The electrode assembly 210, in its extended state, includes a first set 224 of multiple splines 212 located proximal to the deflection direction F, and a second set 226 of multiple splines 212 located distal to the deflection direction F. In one example, the basket axis X is located in a bisector plane perpendicular to the deflection plane 206. The first set 224 of the multiple splines 212 is located proximal 240 of the bisector plane proximal to the deflection direction F (shown in Figure 2 to include the basket axis X). The second set 226 of the multiple splines 212 is located distal 242 of the bisector plane distal to the deflection direction F. An insulator 230 is positioned on the second set 226 of the multiple splines 212 to insulate the associated electrode 214. For example, the insulator 230 is positioned on the ablation electrode on the second set 226 of the multiple splines 212, facing away from the cavity C and opposite to the deflection direction F. The insulator 230 is not positioned on the electrode surface facing toward the cavity C. For the electrode 214 associated with the second set 226 of the multiple splines 212, the electrode surface configured to face toward the cavity C is exposed. Also, the insulator is not positioned on the mapping electrode, and the mapping electrode is exposed. For the ablation electrode 214 associated with the second set 226 of the multiple splines 212, the electrode surface configured to face away from the cavity C is insulated. Furthermore, the insulator 230 is not positioned on the electrode 214 associated with the first set 224 of the multiple electrodes.

[0056] In one example, the catheter 200 operates in unipolar mode to generate an electric field for electroporation. For example, the ablation electrodes on the first set 224 and the second set 226 of the spline 212 may be electrically connected to a single lead conductor extending along the entire length of the shaft 202, or to a set of lead conductors within the shaft 202 configured to transmit the same electrical signal to generate an electric field. The ablation electrodes on the electrode assembly 210 are configured as either anodes or cathodes. None of the electrodes in the electrode assembly are configured as the other of a cathode or anode. Instead, the other of cathode or anode is provided in the form of pad-dispersed electrodes that are placed on the patient during electroporation. The electric field is formed between the activating electrode and the pad-dispersed electrode of the electrode assembly. Through the application of the insulator 230 onto the second set 226 of splines 212, the electrode assembly 210 emits an asymmetric electric field that focuses the electroporation energy into the cavity C and toward the deflection direction F, without emitting an electric field symmetrically in all radial directions from the basket axis X. The lateral field emission corresponds to the deflection plane 206, and the electric field is directed toward the treatment tissue.

[0057] Figures 3A to 3E show some of the many examples of the catheter 200's features. The examples in Figures 3A to 3E are presented as schematic cross-sectional views that can represent the catheter 200 as seen along line 3-3 in Figure 2. For example, Figures 3A to 3E illustrate the deflection plane 206, the basket axis X within the deflection plane 206, the bisecting plane 244 that includes the basket axis X and is perpendicular to the deflection plane 206, the deflection direction F, the cavity C, and the opposite direction B.

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

[0059] Figure 3B shows an exemplary electrode assembly 310B in an extended state, which includes a first set 324B of multiple splines 312B located proximal to the deflection direction F, and a second set 326B of multiple splines 312B located distal to the deflection direction F. Although one spline from each set 324B, 326B is shown in this example, the first set 324B may contain one or more splines, and the second set 326B may contain 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 a plate electrode 306a associated with spline 324B of the first set and a plate electrode 306b associated with spline 326B of the second set. 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. The insulator 330B is positioned on the second set 326B of the plurality of splines 312B to insulate the associated plate electrode 306b. For example, the insulator 330B is positioned on the second set 326B of the plurality of splines 312B on the opposite side of the deflection direction F, and the insulator 330B is provided on the surface 308d of the plate electrode 306b. The insulator 330B is not positioned on the associated electrode 314B of the first set 324B of the plurality of electrodes. Furthermore, the insulator 330B is not placed on the electrode surface facing the cavity C, such as the surface 308c of the plate electrode 308b.

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

[0061] Figure 3D shows an exemplary electrode assembly 310D in an extended state, which includes a first set 324D of multiple splines 312D located proximal to the deflection direction F, and a second set 326D of multiple splines 312D located distal to the deflection direction F. Although one spline from each set 324D, 326D is shown in this example, the first set 324D may contain one or more splines, and the second set 326D may contain one or more splines. In this example, a plate electrode 372 is associated with each spline 312D. For example, each spline 312D may include an elastic support member 374 on which one plate electrode or a plurality of longitudinally spaced plate electrodes are disposed, and at least one electrode from each spline may be used for ablation, such as a plate electrode 372a associated with a first set of splines 324D and a plate electrode 372b associated with a second set of splines 326D. The plate electrode 372a is disposed on the support member 374a. The plate electrode 372a includes an opening 380a, and the mapping electrode 382a is disposed on the first support member 374a. The plate electrode 372b is disposed on the support member 374b. The plate electrode 372b includes an opening 380b, and the mapping electrode 382b is disposed on the first support member 374b.

[0062] Figure 4 shows a partial top view of a spline 324D of a first set having a mapping electrode 382a positioned on a support member 374a within an opening 380a of a plate electrode 372a. The plate electrode 372a may include a plurality of openings spaced longitudinally apart, such as the opening 380a, and a mapping electrode (e.g., mapping electrode 382a) is positioned within each opening for a plurality of mapping electrodes spaced longitudinally along the length of the spline 324D with respect to each spline 312D in the basket.

[0063] Figure 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. The insulator 330D is positioned on the second set 326D of the multiple splines 312D to insulate the associated plate electrode 372b. For example, the insulator 330D is positioned on the second set 326D of the multiple splines 312D on the opposite side of the deflection direction F, and the insulator 330D is provided on the surface 376d of the plate electrode 372b. The insulator 330D is not positioned on the associated electrode 314D of the first set 324D of the multiple electrodes. Furthermore, the insulator 330D is not placed on the mapping electrodes such as the mapping electrode 382b.

[0064] Figure 3E shows an exemplary electrode assembly 310E in an extended state, which includes a first set 324E of multiple splines 312E located proximal to the deflection direction F, and a second set 326E of multiple splines 312E located distal to the deflection direction F. Although one spline from each set 324E, 326E is shown in this example, the first set 324E may contain one or more splines, and the second set 326E may contain 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 a plate electrode 396a associated with spline 326B of the first set and a 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 positioned on the second set 326E of the multiple splines 312E to insulate the associated plate electrode 396b. For example, the insulator 330E is positioned on the second set 326E of the multiple splines 312E on the opposite side of the deflection direction F, and the insulator 330E is provided on the surface 398d of the plate electrode 396b. The insulator 330E is also positioned on the associated electrode 314E of the first set 324E of the multiple electrodes (e.g., surface 396b of the plate electrode 398a).

[0065] In constructing the electroporation catheter 200 shown in Figure 2, an elongated shaft 202 having a distal region 204 and a deflection plane 206 is provided. The elongated shaft 202 defines a longitudinal axis A. The elongated shaft 202 includes lead conductors. An electrode assembly 210 is operably connected 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 spline of the plurality of splines 212 supporting an associated electrode 214. In one example, each spline supports an associated ablation electrode, and each ablation electrode is electrically connected to a lead conductor to receive the same electrical signal. The splines 212 are transitionable between a contracted state and an expanded state. A deflector 220 is constructed or configured within the distal region 204. The deflector 220 is operable in the expanded state to deflect the electrode assembly 210 from axis A toward a deflection direction F in the deflection plane 206. For example, the deflector 220 is connected to the shaft 202, and axis A is determined on the proximal side of the deflector 220. The electrode assembly 210, in its extended state, includes a first set 224 of multiple splines 212 on the proximal side of the deflection direction F and a second set 226 of multiple splines 212 on the distal side of the deflection direction F. The insulator 230 is arranged such that it is deposited on the second set 226 of multiple splines 212 to insulate the associated electrode 214. For example, the insulator 230 is deposited on the second set 226 of multiple splines 212 on the opposite side of the deflection direction F. The insulator 230 is not deposited on the associated electrode 214 of the first set 224 of multiple electrodes.

[0066] Figure 5 shows a portion of an exemplary electroporation catheter 500 constructed according to the electroporation catheter 200 and used in conjunction with an electrophysiological system 50. The exemplary electroporation catheter 500 includes an elongated tubular shaft 502 having a distal region 504 within a deflection plane 506 (shown in Figure 6). The distal region 504 is configured to deploy in the vicinity of target tissue (e.g., within the patient's heart chambers). The elongated shaft 502 defines a longitudinal axis AA. The longitudinal axis AA is shown as a line passing through the centroid of the cross-section of the shaft 502. An electrode assembly 510 is operably connected to the distal region 504 and configured to generate an electric field. In one example, the electric field causes irreversible electroporation in selected cardiac tissue. The electrode assembly 510 includes multiple ablation electrodes 514 (as shown, 514a, 514b, 514c, 514d, 514e, 514f) configured as multiple splines 512 (as shown, 512a, 512b, 512c, 512d, 512e, 512f). Each ablation electrode 514 includes an outer conductive surface 516 and an inner conductive surface 518 on the opposite side. The inner conductive surface 518 faces the cavity CC, and the outer conductive surface 516 faces away from the cavity CC. The ablation electrodes 514 are configured to receive pulsed electrical signals or pulsed waveforms from the electroporation console 130 to generate a pulsed electric field sufficient to ablate the target tissue by irreversible electroporation. Each spline 512 supports an associated mapping electrode 522. For example, multiple associated mapping electrodes 522 are mounted on the outer conductive surface 516 of each ablation electrode 514 and are spaced longitudinally along each spline 512. An insulator may be placed between the mapping electrodes 522 and the associated ablation electrodes 514. The mapping electrodes 522 are configured, among other things, to sense cardiac electrical signals, locate the electrode assembly 510 within the patient's anatomical structure via an EAM system 70 or the like, and determine the proximity to target tissue within the anatomical structure.The mapping electrode 522 within the electrode assembly 510 may be electrically connected to one or more lead conductors extending along the length of the shaft 502, which are configured to transmit electrical signals received by the mapping electrode.

[0067] The spline 512 is transitionable between a contracted state and an expanded state. The deflector 520 is located within the distal region 504. In the expanded state, the deflector 520 is operable to deflect the electrode assembly 510 away from axis AA towards the deflection direction FF in the deflection plane 506. For example, the deflector 520 is connected to the shaft 502, and axis AA is determined on the proximal side of the deflector 520. In the expanded state, the electrode assembly 510 includes a first set 524 of multiple ablation electrodes 514 located proximal to the deflection direction FF, and a second set 526 of multiple ablation electrodes located distal to the deflection direction FF. For example, the first set 524 may include three ablation electrodes 524a, 524b, and 524c, one each on splines 512a, 512b, and 512c, respectively. In the example, the second set 526 may include three ablation electrodes 526a, 526b, and 526c, one on each of the splines 512d, 512e, and 512f, as shown in the figure, but other configurations are also conceivable, such as configurations other than six splines 512, or configurations with multiple ablation electrodes per spline. The insulator 530 is placed on the second set 526 of multiple ablation electrodes 514, covering the outer conductive surface 516 of the associated ablation electrodes 514 with the insulator, while keeping the associated mapping electrodes 522 on the insulated splines 512d, 512e, and 512f exposed and uncovered by the insulator. In one example, the insulator 530 is not placed on the inner conductive surface 518 of the second set 526 of ablation electrodes 514. In these examples, the insulator 530 is not placed on the first set 524 of ablation electrodes 514. In another example, the insulator 530 is placed 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 connected to the shaft 502. The basket 532 may have an expanded length, expanded diameter, and a specific external shape in its 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 approximately perpendicular to the basket axis XX. In the expanded state, the splines 512 are spaced apart from each other, forming a cavity CC within the basket 532. In this example, the splines 512 are constructed from a conductive, flexible elastic material so that the catheter 500 may also be able to transition to a retracted state. In one example, a deployment sheath is positioned over the splines 512, and the catheter 500 is placed in a retracted state while the catheter 500 is in a non-operating mode. When the basket 532 is extended from the deployment sheath, or when the deployment sheath is withdrawn from the basket 532, the basket can be extended and deployed in operating mode.

[0069] The deflector 520 allows the basket 532 to deflect or move away from axis AA, such as toward the treatment site in the deflection plane 506. In one example, the deflector 520 allows the basket 532 to pivot or flex its basket axis XX in the deflection plane 506 with respect to a region on the shaft proximal to the deflector 520. When the basket 532 moves away from the axis, it moves in the deflection direction FF, for example toward the treatment site. When the deflected basket 532 moves toward axis AA, the basket returns to axis AA in the opposite direction BB. When the basket 532 is on the axis, axis AA and basket axis XX are parallel or collinear.

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

[0071] In one example, the catheter 500 operates in unipolar mode to generate an electric field for electroporation. For example, the ablation electrode 514 in the electrode assembly 510 may be electrically connected to a single lead conductor extending along the entire length of the shaft 502, or to a pair of lead conductors in the shaft 502 configured to transmit the same electrical signal to generate an 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 cathode or anode is provided in the form of a pad-dispersed electrode that is placed on the patient during electroporation. The electric field is formed between the activated ablation electrode 514 and the pad-dispersed electrode of the electrode assembly. Through the application of an insulator 530 onto a second set 526 of ablation electrodes 514 with multiple splines 512, the electrode assembly 510 emits an asymmetric electric field that focuses the electroporation energy into the cavity CC and toward the deflection direction FF, without emitting an electric field symmetrically in all directions radially from the basket axis XX. The lateral electric field emission corresponds to the deflection plane 506, and the electric field is directed toward the treatment tissue.

[0072] Figure 6 shows a front cross-sectional view of the basket 532 of catheter 500 in the expanded state. The electrode assembly 510, in the expanded state, includes a first set 524 of ablation electrodes 514 of multiple splines 512 located proximal to the deflection direction FF, and a second set 526 of ablation electrodes 514 of multiple splines 212 located distal to the deflection direction FF. In one example, the basket axis XX is located in a bisector 534 perpendicular to the deflection plane 506. The first set 524 of ablation electrodes 514 of multiple splines 512 is located proximal 540 of the proximal bisector 534 of the deflection direction FF. The second set 526 of electrodes 514 of multiple splines 512 is located distal 542 of the distal bisector 544 of the deflection direction FF. The first set 524 includes three ablation electrodes 524a, 524b, and 524c, one each on splines 512a, 512b, and 512c. The second set 526 may include three ablation electrodes 526a, 526b, and 526c, one each on splines 512d, 512e, and 512f, as shown in the figure, although other configurations are also conceivable, such as configurations other than six splines 512, or configurations with multiple ablation electrodes per spline. The insulator 530 is placed on the second set 526 of multiple ablation electrodes 514, covering the outer conductive surface 516 of the associated ablation electrodes 514 with the insulator, while keeping the associated mapping electrodes 522 on the insulated splines 512d, 512e, and 512f exposed and uncovered by the insulator. In one example, the insulator 530 is not placed on the inner conductive surface 518 of the second set 526 of the ablation electrodes 514. In these examples, the insulator 530 is not placed on the first set 524 of the ablation electrodes 514. In another example, the insulator 530 is placed on the inner surface 518 of each of the first set 524 of the ablation electrodes 514.

[0073] Various modifications and additions can be made to the exemplary embodiments described without departing from the scope of this disclosure. For example, while the embodiments described above refer to specific features, the scope of the 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 invention is intended to encompass all such alternative forms, modifications, and variations included in the claims, along with all their equivalents.

Claims

1. An electroporation catheter for ablation of cardiac tissue, An elongated shaft having a distal region and a deflection plane, the elongated shaft defining the axis, An electrode assembly operably connected to the distal region and configured to generate an electric field, wherein the electrode assembly has a plurality of splines, each spline supporting an associated ablation electrode, and the plurality of splines are transitionable between a contracted state and an expanded state. A deflector located in the distal region, the deflector being operable in the extended state to deflect the electrode assembly off-axis in the deflection direction within the deflection plane, the electrode assembly including in the extended state a first set of the plurality of splines located proximal to the deflection direction and a second set of the plurality of splines located distal to the deflection direction, An electroporation catheter comprising an insulator positioned on the second set of the plurality of splines to insulate at least a portion of the associated ablation electrodes.

2. The electroporation catheter according to claim 1, wherein the plurality of splines form a basket defining 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.

3. The electroporation catheter according to claim 2, wherein the basket can be guided toward the treatment site by the deflector.

4. The electroporation catheter according to any one of claims 1 to 3, wherein the electrode assembly is configured as one of a cathode and an anode to generate an electric field in unipolar mode.

5. The electroporation catheter according to 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. The electroporation catheter according to any one of claims 1 to 3, wherein each ablation electrode associated with the second set of the plurality of splines includes a surface facing the direction of deflection and a surface facing the opposite direction of deflection, and the insulator is disposed on the surface facing the opposite direction of deflection.

7. The electroporation catheter according to any one of claims 1 to 3, wherein each ablation electrode associated with each of the plurality of splines includes a surface facing the direction of deflection and a surface facing the opposite direction of deflection, and the insulator is disposed on the surface facing the opposite direction of deflection.

8. The electroporation catheter according to any one of claims 1 to 3, wherein each spline is formed from the associated ablation electrode.

9. The electroporation catheter according to any one of claims 1 to 3, wherein the electrode assembly further includes a mapping electrode.

10. The electroporation catheter according to any one of claims 1 to 3, wherein each spline further includes a mapping electrode.

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

12. The electroporation catheter according to claim 9, wherein the mapping electrode is not covered by the insulator.

13. The electroporation catheter according to claim 1, wherein each spline includes an elastic support member connected to an electrode.

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

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

Images