Electroporation catheter, electroporation system, and method of assembling an electroporation catheter

Abstract

Disclosed herein is a system and method for an electroporation catheter. The electroporation catheter includes a shaft and a plurality of splines forming a basket around a distal portion of the shaft, each spline extending between a proximal end coupled to the shaft and a distal end coupled to the shaft, each spline of the plurality of splines including at least one energizable electrode. The electroporation catheter further includes a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixation of the position of the plurality of splines.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority to Provisional Application No. 63 / 192,723, filed May 25, 2021, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to tissue ablation systems. In particular, the present disclosure relates to an electroporation catheter including a catheter assembly having a basket and / or balloon.

Background Art

[0003] It is generally known that ablation therapy may be used to treat various conditions that afflict the anatomical structures of the human body. For example, ablation therapy may be used in the treatment of atrial arrhythmias. When tissue is ablated or at least exposed to ablation energy created by an ablation generator and delivered by an ablation catheter, damage is formed in the tissue. To improve conditions such as atrial arrhythmias (including, but not limited to, ectopic atrial tachycardia, atrial fibrillation, atrial flutter, etc.), electrodes attached to or within an ablation catheter are used to cause tissue apoptosis within the heart tissue.

[0004] Arrhythmias (i.e., irregular heart rhythms) can cause various dangerous conditions such as loss of synchronization of atrioventricular contractions and blood flow stasis, and can even lead to various diseases and death. The main cause of atrial arrhythmias is thought to be errant electrical signals within the left or right atrium of the heart. An ablation catheter applies ablation energy (such as high - frequency energy, cryoablation, lasers, chemicals, high - intensity focused ultrasound, etc.) to the heart tissue to form damage in the heart tissue. This damage disrupts unwanted electrical pathways, thereby limiting or preventing the errant electrical signals that lead to arrhythmias.

[0005] Electroporation is a non-thermal ablation technique that applies a strong electric field that induces pore formation in cell membranes. The electric field can be induced, for example, by applying relatively short pulses that can last from nanoseconds to several milliseconds. Such pulses may be repeated to form a pulse train. When such an electric field is applied to tissue in vivo, the cells within the tissue receive a transmembrane potential and the pores in the cell wall open. Electroporation may be reversible (i.e., the temporarily opened pores close again) or irreversible (i.e., the pores remain open). For example, in the field of gene therapy, reversible electroporation (i.e., the pores open temporarily) is used to introduce high molecular weight therapeutic vectors into cells. In other therapeutic applications, cell destruction can be caused, for example, by causing irreversible electroporation using only appropriately configured pulse trains.

Summary of the Invention

Problems to be Solved by the Invention

[0006] In catheters used for the supply of bipolar energy using irreversible electroporation (IRE) or pulsed field ablation (PFA), it is important to ensure that the catheter electrode is close to or in contact with the blood vessel wall. Generally, the closer the electrode is to the blood vessel wall, the larger the damage size. Therefore, a catheter configuration that places the electrode near or in contact with the blood vessel wall is desirable.

Means for Solving the Problems

[0007] In one aspect, an electroporation catheter is provided. The electroporation catheter includes a shaft and a plurality of splines that form a basket around a distal portion of the shaft. Each spline extends between a proximal end coupled to the shaft and a distal end coupled to the shaft, and each spline of the plurality of splines includes at least one energizable electrode. The electroporation catheter further includes a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixing the positions of the plurality of splines.

[0008] In another aspect, an electroporation system is provided. The system includes a generator and a catheter coupled to the generator. The catheter includes a handle, a shaft extending distally from the handle, and a plurality of splines that form a basket around a distal portion of the shaft. Each spline extends between a proximal end coupled to the shaft and a distal end coupled to the shaft, and each spline of the plurality of splines includes at least one energizable electrode. The catheter further includes a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixing the positions of the plurality of splines.

[0009] In yet another aspect, a method of assembling an electroporation catheter is provided. The method includes providing a shaft and coupling a plurality of splines to the shaft to form a basket around a distal portion of the shaft, where each spline extends between a proximal end coupled to the shaft and a distal end coupled to the shaft and each spline of the plurality of splines includes at least one energizable electrode, and disposing a balloon within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixing the positions of the plurality of splines.

[0010] The foregoing and other aspects, features, details, utilities, and advantages of the present disclosure will become apparent from the following description and claims, and by reference to the accompanying drawings.

Brief Description of the Drawings

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[0039] A system and method for an electroporation catheter are described herein. An exemplary electroporation catheter includes a shaft and a plurality of splines that form a basket around a distal portion of the shaft, each spline extending between a proximal end coupled to the shaft and a distal end coupled to the shaft, and each spline of the plurality of splines includes at least one energizable electrode. The electroporation catheter further includes a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixation of the position of the plurality of splines.

[0040] Exemplary embodiments of the present disclosure are described with respect to pulmonary vein isolation (PVI), but it is contemplated that the described features and methods of the present disclosure can be incorporated into any number of systems and any number of applications as will be understood by those skilled in the art based on the disclosure herein.

[0041] FIG. 1 is a block diagram of a system 10 for electroporation therapy. Generally, system 10 includes a catheter electrode assembly 12 disposed at the distal end 48 of a catheter 14. As used herein, "proximal" refers to the direction toward the end of the catheter closer to the clinician, and "distal" refers to the direction away from the clinician and (generally) into the patient's body. The electrode assembly includes one or more individual electrode elements that are electrically insulated. Each electrode element, also referred to herein as a catheter electrode, is individually wired so that it can function as a bipolar or multipolar electrode, selectively paired with or combined with other electrode elements.

[0042] System 10 can be used for irreversible electroporation (IRE) to destroy tissue. In particular, system 10 can be used for primary apoptosis therapy induced by electroporation, which refers to passing an electric current in such a way as to directly cause an irreversible loss of the integrity of the cell membrane (cell wall), resulting in its destruction and cell apoptosis. This mechanism of cell death can be considered an "outside-in" process, meaning that the disruption of the outer wall of the cell has a harmful effect on the inside of the cell. Typically, in classical cell membrane electroporation, the electric current is provided as a pulsed electric field in the form of short pulses (e.g., having a duration of 0.1 to 20 milliseconds (ms)) between adjacent but spaced electrodes that can provide an electric field strength of about 0.1 to 1.0 kilovolts / centimeter (kV / cm). System 10 can be used, for example, with basket and / or balloon catheter assemblies for high-power (e.g., high voltage and / or high current) electroporation procedures. In some particular embodiments, system 10 is configured to provide an electroporation pulse signal with a relatively high voltage and a short pulse duration.

[0043] In one embodiment, all the electrodes of the catheter conduct current simultaneously. Alternatively, in other embodiments, stimulation is applied between a pair of electrodes on the catheter. By simultaneously conducting current using multiple electrodes, it may be easier to form damage that is deep enough to perform electroporation. To facilitate simultaneous activation of the electrodes, the electrodes may be made switchable between connection to a 3D mapping system and connection to an EP amplifier.

[0044] Irreversible electroporation using the catheter described herein may enable pulmonary vein isolation with about one shock per vein, and the treatment time can be significantly shortened compared to continuously placing high-frequency (RF) ablation chips around the vein.

[0045] The energization method is described with respect to DC pulses, but it should be understood that embodiments may use variations and remain within the spirit and scope of the present disclosure. For example, exponentially decaying pulses, exponentially increasing pulses, and combinations thereof may be used. Further, in some embodiments, AC pulses may be used.

[0046] Furthermore, it should be understood that the mechanism of cell destruction in electroporation is not mainly due to the heating effect, but rather due to the destruction of the cell membrane by the application of a high-voltage electric field. Thus, electroporation can somewhat avoid the thermal effects that can occur when using high-frequency (RF) energy. This “cryotherapy” has desirable characteristics.

[0047] With this background in mind, referring again to FIG. 1, system 10 includes a catheter electrode assembly 12 that includes at least one catheter electrode. The electrode assembly 12 is incorporated as part of a medical device such as a catheter 14 for electroporation treatment of tissue 16 within a patient's body 17. In an exemplary embodiment, tissue 16 includes the heart or heart tissue. However, it should be understood that embodiments can be used to perform electroporation treatment on a variety of other body tissues.

[0048] FIG. 1 further shows a plurality of feedback electrodes 18, 20, 21, which can be used by various subsystems included in the overall system 10, such as an electroporation generator 26, an electrophysiology (EP) monitor such as an ECG monitor 28, and a positioning and navigation system 30 for visualization, mapping, and navigation of internal structures. In the illustrated embodiment, feedback electrodes 18, 20, 21 are patch electrodes. The illustration of a single patch electrode is schematic (for clarity), and such subsystems to which these patch electrodes are connected may include more than one patch (body surface) electrode, typically will include more than one patch (body surface) electrode, and may include split patch electrodes (as described herein). In other embodiments, feedback electrodes 18, 20, 21 may be other types of electrodes suitable for use as feedback electrodes, including, for example, one or more catheter electrodes. A feedback electrode that is a catheter electrode may be part of the electrode assembly 12 or part of a separate catheter or device (not shown). System 10 may further include a main computer system 32 (including an electronic control unit 50 and a data storage memory 52), which may be integrated with the positioning and navigation system 30 in certain embodiments. System 32 may further include conventional interface components such as various user input / output mechanisms 34A and a display 34B, among other components.

[0049] The electroporation generator 26 is configured to energize the electrode elements according to an electroporation energization method, which may be pre-determined or selectable by the user. For the primary apoptosis therapy induced by electroporation, the generator 26 can provide an electric field strength of about 0.1 to 1.0 kV / cm (i.e., at the tissue site) in the form of a pulsed electric field of short-duration DC pulses (e.g., having a duration from nanoseconds to several milliseconds, a duration of 0.1 to 20 milliseconds, or any duration suitable for electroporation) between closely spaced but separated electrodes, and is configured to generate a current provided via the electrode assembly 12. The amplitude and pulse duration required for irreversible electroporation are in an inverse relationship. As the pulse duration shortens, the amplitude must be increased to achieve electroporation.

[0050] The electroporation generator 26, which may also be referred to herein as a DC energy source, is a unipolar electroporation generator 26 configured to generate a series of DC energy pulses that all generate current in the same direction. In other embodiments, the electroporation generator is a bipolar or multipolar electroporation generator configured to generate DC energy pulses that do not all generate current in the same direction. In some embodiments, the electroporation generator 26 is configured to output the energy of the DC pulse at selectable energy levels such as 50 joules, 100 joules, 200 joules, etc. Other embodiments may have more or fewer energy settings, and the available set values may be the same or different. To successfully perform electroporation, some embodiments utilize an output level of 200 joules. For example, the electroporation generator 26 may output a DC pulse having a peak magnitude from about 300 volts (V) to about 3,200 V at an output level of 200 joules. In some embodiments, the peak magnitude may be even greater (e.g., about 10,000 V). In other embodiments, any other suitable positive or negative voltage may be output. For example, in some embodiments, the systems and methods described herein can include pulses having a pulse width from about 200 nanoseconds to about 20 microseconds and an amplitude from about 500 V to about 4,000 V.

[0051] In some embodiments, the variable impedance 27 can vary the impedance of the system 10 to limit arc discharge. Additionally, the variable impedance 27 can be used to modify one or more characteristics such as the amplitude, duration, pulse shape, etc. of the output of the electroporation generator 26. Although shown as an independent component, the variable impedance 27 may be incorporated into the catheter 14 or the generator 26.

[0052] Continuing to refer to FIG. 1, as described above, the catheter 14 may include functions for electroporation and, in certain embodiments, may also include functions for other types of ablation (e.g., RF ablation). However, it should be understood that in those embodiments, the type of ablation energy provided (e.g., cryoablation, ultrasound, etc.) can vary.

[0053] In the illustrated embodiment, the catheter 14 includes a cable connector or interface 40, a handle 42, and a shaft 44 having a proximal end 46 and a distal end 48. The catheter 14 can also include other conventional components not shown herein, such as temperature sensors, additional electrodes, and corresponding conductors or lead wires. The connector 40 provides a mechanical and electrical connection to a cable 56 extending from the generator 26. The connector 40 can include conventional components known in the art and is disposed at the proximal end of the catheter 14 as shown.

[0054] The handle 42 can provide a place for the clinician to hold the catheter 14 and further provide means for manipulating or guiding the shaft 44 within the body 17. For example, the handle 42 can include means for changing the length of a guide wire that extends through the catheter 14 to the distal end 48 of the shaft 44, or means for manipulating the shaft 44. Further, in some embodiments, the handle 42 may be configured to change the shape, size, and / or orientation of a portion of the catheter, and it will be understood that the structure of the handle 42 can vary. In another embodiment, the catheter 14 may be driven or controlled by a robot. Thus, instead of the clinician operating the handle to advance / retreat and / or direct or guide the catheter 14 (and in particular its shaft 44), a robot is used to operate the catheter 14. The shaft 44 is an elongated tubular flexible member configured to move within the body 17. The shaft 44 is configured to support the electrode assembly 12 and include associated conductors and, in some cases, additional electronics used for signal processing or conditioning. The shaft 44 can also enable the transport, delivery, and / or removal of fluids (including irrigation fluid and body fluid), pharmaceuticals, and / or surgical instruments or devices. The shaft 44 may be made of a conventional material such as polyurethane and define one or more lumens configured to house and / or transport conductors, fluids, or surgical instruments as described herein. The shaft 44 can be introduced into a blood vessel or other structure within the body 17 via a conventional introducer. The shaft 44 can then be advanced / retreated and / or directed or guided through the body 17 to a desired location such as a site of tissue 16, which includes the intervention of using a guide wire or other means known in the art.

[0055] In some embodiments, the catheter 14 includes a basket catheter assembly having catheter electrodes (not shown in FIG. 1) disposed at the distal end of the shaft 44 within the basket structure. Further, as described herein, an inflatable balloon may be housed within the basket structure.

[0056] A positioning and navigation system 30 can be provided for visualizing, mapping, and navigating internal structures. The positioning and navigation system 30 may include a conventional device generally known in the art (e.g., the ENSITE PRECISION (trademark) system generally shown with reference to U.S. Patent No. 7,263,397, by the same applicant, titled "Method and Apparatus for Catheter Navigation and Location and Mapping in the Heart," commercially available from ABBOTT LABORATORIES and incorporated herein by reference in its entirety). However, it should be understood that this system is exemplary and not inherently limiting. Other techniques for positioning / navigating (and visualizing) a catheter within a space are known, for example, the CARTO navigation and positioning system of Biosense Webster, the RHYTHMIA (registered trademark) system of Boston Scientific Scimed, the KODEX (registered trademark) system of KONINKLIJKE PHILIPS N.V., the AURORA (registered trademark) system of Northern Digital, a generally available fluoroscopy system, or a magnetic position system such as the gMPS system of Mediguid. In this regard, some of the positioning, navigation, and / or visualization systems involve the provision of sensors to generate signals indicative of the position information of the catheter, for example, including one or more electrodes in the case of an impedance-based positioning system, or one or more coils (i.e., wire windings) configured to detect one or more characteristics of a magnetic field in the case of, for example, a magnetic field-based positioning system. As yet another example, the system 10 can utilize a combination system based on electric fields and magnetic fields, generally shown with reference to U.S. Patent No. 7,536,218, titled "Hybrid Magnetic-Based and Impedance Based Position Sensing," incorporated herein by reference in its entirety.

[0057] Pulsed field ablation (PFA) has been shown to be an effective form of ablation for the treatment of cardiac arrhythmias, particularly for the purpose of instantaneous pulmonary vein isolation (PVI). PFA involves delivering high voltage pulses from electrodes disposed on a catheter (including, for example, the basket catheters and / or balloon catheters described herein). In PFA, for example, the voltage amplitude may range from about 300 V to at least 3,200 V (or as large as about 10,000 V), and the pulse width may range from several hundred nanoseconds to several tens of milliseconds.

[0058] These electric fields can be applied between adjacent electrodes (in the bipolar approach) or between one or more electrodes and a return patch (in the unipolar approach). Each of these approaches has advantages and disadvantages (for example, when using the basket and / or balloon catheters described herein).

[0059] For example, with respect to the spread of damage, in the unipolar approach, there may be a gap (referred to as a dead zone) left in the damage area between electrodes where the electric field strength is low or zero, while the electric field strength of the bipolar approach can generally prevent a dead zone between electrodes.

[0060] Regarding the size and proximity of damage, the unipolar approach has a wider effective range and may be able to form deeper damage at the same applied voltage. Furthermore, the unipolar approach can create damage from a distance (for example, generally in close proximity but not necessarily in contact with the tissue). In the bipolar approach, smaller damage can be formed, and proximity or contact with the tissue is required to form a transmural lesion. However, the unipolar approach may form damage that is larger than necessary, and the damage resulting from the bipolar approach may be more local.

[0061] The monopolar approach has a wide effective range, which may unnecessarily activate skeletal muscles and nerves. On the other hand, the bipolar approach has an effective range limited in proportion to the electrode spacing on the lead and is less likely to eliminate the polarity of cardiomyocytes and nerve fibers.

[0062] In the monopolar approach, only a single potential is applied to the catheter wire and the electrodes. Further, since all the electrodes have the same polarity, (for example, when using the basket catheter and / or balloon catheter described herein,) this configuration is less susceptible to the effects of arc discharge. In contrast, in the bipolar approach, since the various electrodes are at various potentials, it is necessary to construct the internal structure of the catheter to prevent arc discharge.

[0063] To monitor the operation of system 10, one or more impedances between the catheter electrodes and / or the return electrodes 18, 20, 21 may be measured. For example, in the case of system 10, the impedance may be measured as described in U.S. Patent Application Publication No. 2019 / 0117113, filed Oct. 23, 2018, U.S. Patent Application Publication No. 2019 / 0183378, filed Dec. 19, 2018, and U.S. Patent Application No. 63 / 027,660, filed May 20, 2020, all of which are hereby incorporated by reference in their entirety.

[0064] FIG. 2 is a diagram of one embodiment of a handle 200 that can be used with system 10 and catheter 14. Handle 200 includes a first actuator 222 and a second actuator 224. The first actuator 222 may be rotatable, for example, about a rotational axis that is substantially perpendicular to the longitudinal axis of the handle 200 to selectively deflect at least a portion of the catheter 14. The second actuator 224 may be rotatable, for example, about the same axis as the first actuator 222 and can selectively lock the deflected orientation of the catheter 14. That is, the first actuator 222 can be operated to deflect at least a portion of the catheter 14 to a desired orientation, and then the second actuator 224 can be operated to lock the catheter 14 in that orientation. Accordingly, the first actuator 222 and the second actuator 224 can be connected to one or more activation wires extending within the catheter 14.

[0065] Further, as shown in FIG. 2, a plurality of connectors 230 are coupled to the handle 200 by cables 232. The connectors 230 can be used to connect the catheter 14 to a generator such as generator 26 (shown in FIG. 1). Further, the connectors 230 can provide an interface between a positioning and navigation system, such as positioning and navigation system 30 (shown in FIG. 1), and one or more magnetic sensors included in the catheter 14, as will be described in more detail below.

[0066] Those skilled in the art will understand that the handle 200 is merely exemplary and that any suitable handle and / or actuator arrangement may be utilized to implement the systems and methods described herein.

[0067] FIG. 3 is a schematic side view of an embodiment of a catheter assembly 300 that can be used with the system 10 (shown in FIG. 1). The catheter assembly 300 includes a shaft 302 and a balloon 304 coupled to the distal end 305 of the shaft 302. In this embodiment, the catheter assembly 300 includes a first electrode 308 at the proximal end 310 of the balloon 304 and a second electrode 312 at the distal end 314 of the balloon 304. The catheter assembly 300 is shown disposed within the pulmonary vein 320.

[0068] FIG. 4 is a schematic side view of an alternative embodiment of a catheter assembly 402 that can be used with the system 10 (shown in FIG. 1). The catheter assembly 400 includes a shaft 400 and a balloon 404 coupled to the distal end 406 of the shaft 402. In this embodiment, the catheter 400 includes a plurality of electrodes 412 proximate to the distal end 414 of the balloon 404. The electrodes 412 extend outwardly from the balloon 404 so as to be proximate to the wall of the pulmonary vein 320, unlike the second electrode 312 shown in FIG. 3. In this embodiment, the catheter assembly 400 includes eight electrodes 412 (only five are shown for clarity). Alternatively, the catheter assembly 400 may include any suitable number of electrodes 412.

[0069] In this embodiment, each electrode 412 is coupled to a corresponding spline (not shown). The spline and the electrode 412 fit within the inner lumen of the catheter assembly 400 during delivery. Upon deployment of the catheter assembly 400, the spline expands outwardly (e.g., like an umbrella) so that the electrodes 412 are proximate to or in contact with the wall of the pulmonary vein 320. Using the catheter assembly 400, sufficient damage can be caused with an applied voltage of 1,400 V to 2,500 V even in a pulmonary vein with a diameter of 25 mm.

[0070] FIG. 5 is a schematic side view of an alternative embodiment of a catheter assembly 500 that can be used with the system 10 (shown in FIG. 1). The catheter assembly 500 includes a shaft 502 and a balloon 504 coupled to the distal end 506 of the shaft 502. In this embodiment, the catheter assembly 500 includes a plurality of electrodes 512 proximate the distal end 514 of the balloon 504. The electrodes 512, unlike the second electrodes 312 shown in FIG. 3, are disposed on a loop 516 so as to be proximate to the wall of the pulmonary vein 320. The loop 516 and the electrodes 512 fit within the inner lumen of the catheter assembly 500 during delivery. Upon deployment of the catheter assembly 500, the loop 516 deploys such that the electrodes 512 are proximate to, or in contact with, the wall of the pulmonary vein 320.

[0071] In this embodiment, the catheter assembly 500 includes 14 electrodes 512 (only half of the loop 514 and 8 electrodes 512 are shown for clarity). Alternatively, the catheter assembly 500 may include any suitable number of electrodes 512. Using the catheter assembly 500, sufficient damage can be caused even in a pulmonary vein with a diameter of 25 mm at an applied voltage of 2,000 V or 2,500 V.

[0072] FIG. 6 is a schematic side view of an alternative embodiment of a catheter assembly 600 that can be used with the system 10 (shown in FIG. 1). The catheter assembly 600 includes a shaft 602 and a balloon 604 coupled to the distal end 606 of the shaft 602. In this embodiment, the catheter assembly 600 includes a plurality of pre-formed splines 612 that function as electrodes. The splines 612 may fit within the inner lumen of the catheter assembly 600 during delivery or may surround the balloon 604. In embodiments where the splines 612 fit within the inner lumen, the splines 612 may expand radially outward when deployed such that the splines 612 are proximate to, or in contact with, the wall of the pulmonary vein 320.

[0073] In the illustrated embodiment, the catheter assembly 600 includes 12 splines 612 (although only 7 splines 612 are shown). Alternatively, the catheter assembly 600 can include any suitable number of splines 612. For example, in some embodiments, the catheter assembly 600 can include from 10 to 16 splines 612.

[0074] The splines 612 can be made of nitinol, stainless steel, and / or other superalloys. Further, the entire spline 612 can function as an electrode, or a portion of each spline 612 can be covered with an insulating material (e.g., polyethylene terephthalate (PET) heat shrink material, or polyether block amide (PEBA) material) such that only the non-insulated portion of each spline 612 functions as an electrode. Additionally, in some embodiments, a plurality of independently energizable electrodes are attached to each spline 612. By using the catheter assembly 600, sufficient damage can be generated even in a pulmonary vein with a diameter of 25 mm at an applied voltage of 2,000 V or 2,500 V.

[0075] The splines 612 can be formed, for example, by laser cutting a tube (e.g., made of nitinol, stainless steel, and / or other superalloys) into a plurality of strips and heat treating the strips to form a shape that conforms to the balloon 604.

[0076] FIG. 7 is a side schematic view of the inner lumen 630 of the catheter assembly 600 with the splines 612 housed within the inner lumen 630 (e.g., during delivery of the catheter assembly 600 and prior to deployment of the splines 612). FIG. 8 is a perspective schematic view showing the splines 612 deployed from the inner lumen 630.

[0077] The splines 612 may all be electrically connected to each other as a single electrode, or each may be an individual electrode. When the splines 612 are individual electrodes, each spline 612 may be selectively energizable to form different energization sequences and / or patterns. Generally, each spline 612 has the same polarity to avoid problems with arc discharge.

[0078] The splines 612 may all be of the same length, or at least a portion of the splines 612 may be of different lengths. Further, the splines 612 may include an insulating material covering at least a portion of each spline 612. The insulating material of each spline 612 may be of the same length, or at least some of the splines 612 may have insulating materials of different lengths. Further, in some embodiments, the catheter assembly 600 includes a distal electrode (not shown) disposed distally of the splines 612. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 612), and / or may be used for visualization / mapping (e.g., by using the distal electrode in combination with an electrode on the shaft 602).

[0079] FIG. 9A is a perspective view of an alternative embodiment of a catheter assembly 900, and FIG. 9B is a schematic side view of the catheter assembly 900. The catheter assembly 900 includes a shaft 902 and a plurality of splines 904 surrounding a distal portion 906 of the shaft 902. Each spline 904 includes a proximal end 910 coupled to the shaft 902 and a distal end 912 coupled to the shaft 902. The spline 904 extends radially outward from the proximal end 910 to an inflection point 914 and then radially inward to the distal end 912. FIG. 9B shows the catheter assembly 900 disposed within the pulmonary vein 320.

[0080] The body of each spline 904 is made of an elastic material (e.g., nitinol) and functions as a relatively large electrode. In this embodiment, the alternating splines 904 alternate in polarity. That is, each positive spline 904 is disposed between two negative splines 904, and vice versa. Alternatively, any suitable polarization scheme may be used.

[0081] To control the ablation zone of each spline 904, a portion of each spline 904 may be covered with an insulating material 920 (e.g., heat shrink (e.g., PET) or polymer tubing, or a spray or dip coat using polyimide or PEBA), and the exposed portion of the spline 904 functions as an electrode. In the embodiment shown in FIGS. 9A and 9B, the inflection point 914 and the portion of the spline 904 between the inflection point 914 and the distal end 912 are generally exposed, while the portion of the spline 904 between the inflection point 914 and the proximal end 910 is generally insulated. As a result, the portion of the spline 904 that contacts the pulmonary vein 320 is exposed (see FIG. 9B). Alternatively, any suitable insulation configuration may be used.

[0082] During delivery, the spline 904 can be collapsed and oriented substantially parallel to the shaft 902 (i.e., with the inflection point 914 close to the shaft 902). Thereafter, to perform ablation, the spline 904 is deployed with the inflection point 914 radially expanded.

[0083] Notably, compared to the catheter assemblies 300, 400, 500, 600 shown in FIGS. 3-6, the catheter assembly 900 facilitates ablation of a more proximal and wider portion of the pulmonary vein 320.

[0084] The splines 904 may all be the same length, or at least some of the splines 904 may be of different lengths. Further, the insulating material 920 of each spline 904 may be of the same length, or at least some of the splines 904 may have insulating material 920 of different lengths. Further, in some embodiments, the catheter assembly 900 includes a distal electrode (not shown) disposed distally of the splines 904. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 904), and / or may be used for visualization / mapping (e.g., by using the distal electrode in combination with an electrode on the shaft 902).

[0085] FIG. 10A is a perspective view of a catheter assembly 1000 of an alternative embodiment, and FIG. 10B is a schematic side view of the catheter assembly 1000. The catheter assembly 1000 includes a shaft 1002 and a plurality of splines 1004 surrounding the distal portion 1006 of the shaft 1002, similar to the catheter assembly 900 shown in FIG. 9. However, in contrast to the catheter assembly 900, the catheter assembly 1000 includes a balloon 1008 surrounded by the splines 1004. The balloon 1008 may be selectively inflated to occupy the space between the splines 1004. It should be noted that the balloon 1008 functions as an insulator and generally reduces energy loss compared to the catheter assembly 900, and as a result, may increase the size of the lesion.

[0086] Each spline 1004 includes a proximal end 1010 coupled to the shaft 1002 and a distal end 1012 coupled to the shaft 1002. The spline 1004 extends radially outward from the proximal end 1010 to an inflection point 1014 and then extends radially inward to the distal end 1012. FIG. 10B shows the catheter assembly 1000 disposed within the pulmonary vein 320.

[0087] During delivery, the spline 1004 and the balloon 1008 may be crushed. To perform ablation, the spline 1004 is deployed with the inflection point 1014 spreading radially outward, and the balloon 1008 is selectively inflated to occupy the space between the splines 1004.

[0088] In some embodiments, the shape of the balloon 1008 can be selectively changed to improve ablation. For example, FIG. 10C is a schematic view showing the catheter assembly 100 in the first configuration 1030, and FIG. 10D is a schematic view showing the catheter assembly 100 in the second configuration 1032. In the second configuration 1032, the spline 1004 is axially compressed compared to the first configuration 1030 such that the effective diameter of the spline 1004 is increased.

[0089] To facilitate selectively transitioning the balloon catheter assembly 100 between the first configuration 1030 and the second configuration 1032, an inner shaft member (not shown in FIGS. 10A - 10D) can be slidably disposed within the shaft 1002 with the distal end of the inner shaft member coupled to the distal end 1034 of the balloon 1008 and the spline 1004. When the inner shaft member is pulled proximally relative to the shaft 1002, the distal end 1034 of the balloon 1008 and the spline 1004 are also pulled proximally relative to the proximal end 1036 of the balloon 1008 and the spline 1004, and the balloon 1008 and the spline 1004 are axially compressed. The position of the inner shaft member relative to the shaft 1002 can be held in a predetermined position using a suitable locking mechanism (e.g., a Tuohy Borst compression valve) as described in detail herein.

[0090] FIG. 10E is a side cross-sectional view of the catheter assembly 1000. As shown in FIG. 10E, the catheter assembly 1000 can include one or more magnetic sensors (e.g., to facilitate determining the position and / or orientation of the catheter assembly 1000 within a patient). In this embodiment, a hollow core magnetic sensor 1050 is disposed proximate the distal end 1034 of the balloon 1008. The central lumen 1052 of the shaft 1002 can extend therethrough by way of the hollow core magnetic sensor 1050. The hollow core magnetic sensor 1050 can have, for example, sensing capabilities over five degrees of freedom (enabling position detection in the X, Y, and Z directions). The central lumen 1052 can be used, for example, to accommodate a guide wire, to accommodate a small diameter mapping catheter, and / or to inject a contrast agent into the patient (e.g., to facilitate determining the position of the catheter assembly 1000). Further, in some embodiments, two or more electrodes (not shown) are coupled to the shaft 1002 to facilitate impedance-based localization.

[0091] The catheter assembly 1000 also includes two solid core magnetic sensors 1060 disposed proximate the proximal end 1036 of the balloon 1008. The solid core magnetic sensors 1060 can be, for example, embedded in the shaft 1002, but are disposed outside of the central lumen 1052. Each of the solid core magnetic sensors 1060 individually has sensing capabilities over five degrees of freedom, but when combined have sensing capabilities over six degrees of freedom (enabling position detection in the X, Y, and Z directions and detection of the roll of the catheter assembly 1000).

[0092] In this embodiment, the central lumen 1052 facilitates the supply of fluid into the interior of the balloon 1008 and selectively inflates the balloon 1008. The fluid can include saline or a mixture of saline and a contrast agent. In some embodiments, the shaft 1002 can include irrigation holes (not shown) that provide fluid communication between the central lumen 1052 and the interior of the balloon 1008. Further, in some embodiments, the central lumen 1052 enables the injection of a contrast agent distally of the catheter assembly 1000, thereby assisting the user in evaluating blood flow through the pulmonary vein 320 and in evaluating the degree to which the catheter assembly 1000 occludes the pulmonary vein 320.

[0093] Figures 10F - 10J are schematic side cross-sectional views of the catheter assembly 1000 showing the transition of the catheter assembly 1000 between different states. As shown in Figure 10F, in this embodiment, the shaft 1002 includes an outer shaft element 1062 and an inner shaft element 1064, both of which are tubular components. The inner shaft element 1064 is axially slidable within the outer shaft element 1062 and defines a central lumen 1052 that extends therethrough. The outer shaft element 1062 can have a French size of, for example, 11.5 French. Alternatively, the outer shaft element 1062 can have any suitable dimensions.

[0094] The valve 1066 at the distal end of the inner shaft element 1064 controls access to the central lumen 1052. For example, as described above, a contrast agent can be flowed through the central lumen 1052 to the patient to confirm pulmonary vein occlusion. As another example, a mapping catheter (e.g., a 3 French mapping catheter) may extend through the central lumen 1052 into the patient. As yet another example, a guidewire may extend through the central lumen 1052. Those skilled in the art will understand that the occlusion can be monitored using any suitable technique. For example, pressure monitoring may be used to evaluate venous occlusion, contrast agent injection may be used to evaluate venous occlusion using fluoroscopy, and / or ultrasound (e.g., Doppler) may be used to evaluate the occlusion.

[0095] As shown in FIG. 10F, in this embodiment, a channel 1070 is defined between the outer shaft element 1062 and the inner shaft element 1064. The channel is in fluid communication with the interior of the balloon 1008. Further, a stopcock valve 1072 (e.g., a three-way stopcock valve) enables the balloon to be inflated and deflated as desired by controlling the flow of fluid into the interior of the balloon 1008.

[0096] In some embodiments, shape sensing fibers may extend through the central lumen 1052 and / or the channel 1070. The shape sensing fibers may be optical fibers that enable a user to accurately determine the position and orientation of the shape sensing fibers and, thus, the position and orientation of the shaft 1002.

[0097] In this embodiment, the catheter assembly 1000 further includes a compression valve 1080 that facilitates fixing the position of the outer shaft element 1062 relative to the inner shaft element 1064. Specifically, when the compression valve 1080 is open, the inner shaft element 1064 is slidable relative to the outer shaft element 1062. Once the inner shaft element 1064 is in the desired position, the compression valve 1080 may be closed to prevent the inner shaft element 1064 from sliding relative to the outer shaft element 1026. The compression valve 1080 also seals the proximal end of the channel 1070.

[0098] As shown in FIG. 10F, each spline 1004 extends between the distal end 1084 of the outer shaft element 1026 and the distal end 1086 of the inner shaft element 1064. Thus, the shape of the spline 1004 is adjustable by sliding the distal end 1086 of the inner shaft element relative to the distal end 1084 of the outer shaft element.

[0099] FIG. 10F shows the spline 1004 in a neutral position with the balloon 1008 deflated. Specifically, in this embodiment, the spline 1004 is made of a shape memory material (e.g., nitinol) such that the spline 1004 assumes the shape shown in FIG. 10F when not subjected to an external force or bias.

[0100] To compress the catheter assembly 1000 (e.g., for delivery of the catheter assembly 1000), the inner shaft element 1064 is slid distally relative to the outer shaft element 1062. This causes the spline 1004 to collapse inwardly towards the inner shaft element, shifting the catheter assembly 1000 to a collapsed position as shown in FIG. 10G. In FIG. 10G, the balloon 1008 is deflated. The catheter assembly 1000 can be locked in the collapsed position using the compression valve 1080.

[0101] Referring now to FIG. 10H, during treatment, balloon 1008 expands to fill the space between splines 1004. Specifically, as shown in FIG. 10H, with balloon 1008 in an inflated state, balloon 1008 generally conforms to the shape of the basket formed by splines 1004.

[0102] As described above in connection with FIGS. 10C and 10D, the basket formed by splines 1004 may be compressed to increase the outer diameter of catheter assembly 1000. Specifically, as shown in FIG. 10I, when inner shaft element 1064 is slid proximally relative to outer shaft element 1062, this causes splines 1004 to flex outwardly and catheter assembly 1000 to move to a compressed position. In FIG. 10I, balloon 1008 is deflated. Catheter assembly 1000 can be locked in the compressed position using compression valve 1080.

[0103] Referring now to FIG. 10J, at the compressed position, balloon 1008 can be inflated to fill the space between splines 1004. Specifically, as shown in FIG. 10J, with balloon 1008 in an inflated state, balloon 1008 generally conforms to the shape of the basket formed by splines 1004 at the compressed position.

[0104] FIG. 10K is a side cross-sectional view of a portion of handle 1090 that can be used with catheter assembly 1000. Handle 1090 includes housing 1091 and a compression valve component 1092 disposed within housing 1091 (e.g., including compression valve 1080). Further, handle 1090 includes a rotatable knob 1093 coupled to compression valve component 1092 at the distal end of housing 1091. By rotating knob 1093, a user can selectively open and close compression valve 1080 to fix the position of inner shaft element 1064 as desired.

[0105] Further, as shown in FIG. 10K, a positioning component 1094 is coupled to the distal end of the inner shaft element 1064. With the compression valve 1080 open, the positioning component 1094 can axially slide relative to the housing 1091 to slide the inner shaft element 1064 relative to the outer shaft element 1062 as described above. A first fluid supply line 1095 (i.e., for supplying fluid to the central lumen 1052) and a second fluid supply line 1096 (i.e., for supplying fluid to the channel 1070) are also shown in FIG. 10K.

[0106] To prevent rotation of the positioning component 1094 and the first fluid supply line 1095 relative to the housing 1091, a pin 1097 non-rotatably couples the positioning component 1094 to the compression valve component 1092. Specifically, as shown in the perspective view of FIG. 10L and the exploded view of FIG. 10M, a ring 1098 couples the pin 1097 to the compression valve component 1092. The ring 1098 has a protrusion 1099 that engages slots defined in the compression valve component 1092 and the pin 1097 so that the pin 1097 (and thus the positioning component 1094) cannot rotate relative to the compression valve component 1092.

[0107] In some embodiments, one or more lumens are defined within the outer shaft element 1062 (e.g., between the inner and outer surfaces of the outer shaft element 1062). The lumens can be used to route electrical wires (i.e., for supplying power to the spline 1004) and / or activation wires (i.e., for controlling the orientation of the catheter assembly 1000) through the catheter assembly 1000. For example, in one embodiment, all of the positive electrical wires that supply energy to the positive spline 1004 are routed through a first lumen, and all of the negative electrical wires that supply energy to the negative spline are routed through a second separate lumen. This effectively separates the positive electrical wires from the negative electrical wires.

[0108] Each electrical wire may be coupled to the associated spline 1004, for example, via a weld, and the weld and the proximal end of the spline are disposed on a proximal coupler component (not shown). Further, in some embodiments, a strain relief component (not shown) is coupled to the outside of the inner shaft element 1064 on the distal side of the outer shaft element 1062 to prevent the inner shaft element 1064 from bending excessively.

[0109] The catheter assembly 1000 has several advantages. For example, the combination of the balloon 1008 and the spline 1004 facilitates the straight delivery and deployment of the catheter assembly 1000. Further, the balloon 1008 delivers more energy to the ablated tissue, stabilizes the spline 1004, and prevents lateral movement. Further, using the spline 1004 as an electrode instead of individual small electrodes promotes cost reduction and improves the reliability of the catheter assembly 1000.

[0110] All of the splines 1004 may be the same length, or at least some of the splines 1004 may be of different lengths. Further, the insulating material (e.g., PET or PEBA material) on each spline 1004 may be the same length, or at least some of the splines 1004 may have insulating material of different lengths. Further, in some embodiments, the catheter assembly 1000 includes a distal electrode (not shown) disposed distally of the spline 1004. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1004), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1002).

[0111] FIG. 11 is a perspective view of a catheter assembly 1100 of an alternative embodiment. The catheter assembly 1100 includes a shaft 1102 and a plurality of splines 1104 surrounding a distal portion 1106 of the shaft 1102. Each spline 1104 includes a proximal end 1110 coupled to the shaft 1102 and a distal end 1112 coupled to the shaft 1102. From the proximal end 1110 to the distal end 1112, the spline 1104 has an arcuate shape extending radially outward.

[0112] In this embodiment, each spline 1104 includes a plurality of individual electrodes 1120. For example, each spline 1104 can include an elastic material (e.g., nitinol) covered with a polymer tube 1122, and the individual electrodes 1120 are attached to the outside of the polymer tube 1122. In the illustrated embodiment, each spline 1104 includes two electrodes 1120. Further, as shown in FIG. 11, the electrodes 1120 are generally disposed closer to the distal end 1112 than the proximal end 1110 so as to correspond to the portion of the spline 1104 that contacts the pulmonary vein 320.

[0113] Alternatively, each spline 1104 may include any suitable number and arrangement of electrodes 1120. For example, in some embodiments, each spline 1104 includes four electrodes 1120.

[0114] In this embodiment, alternating splines 1104 alternate in polarity. That is, the electrodes 1120 on a particular spline 1104 have the same polarity, but the electrodes 1120 on a particular spline 1104 have a different polarity from the electrodes 1120 on an adjacent spline 1104. Alternatively, any suitable polarization scheme may be used. During delivery, the spline 1104 can collapse toward the shaft 1102. Thereafter, to perform ablation, the spline 1104 is deployed to expand radially outward.

[0115] Instead of the elastic material of the spline 1104 itself being the electrode 1120, including a plurality of electrodes 1120 in each spline 1104 allows each electrode 1120 to be used as an individual sensor for acquiring mapping data, thus improving the ability of the catheter assembly 1100 to execute various mapping routines.

[0116] All the splines 1104 may be of the same length, or at least a part of the splines 1004 may have different lengths. Further, the insulating material (e.g., PET or PEBA material) on each spline 1104 may be of the same length, or at least some of the splines 1104 may have insulating materials of different lengths. Additionally, in some embodiments, the catheter assembly 1100 includes a distal electrode (not shown) disposed distally of the spline 1104. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1104), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1102).

[0117] FIG. 12 is a perspective view of a catheter assembly 1200 of an alternative embodiment. The catheter assembly 1200 includes a shaft 1202 and a plurality of splines 1204 surrounding the distal portion 1206 of the shaft 1202, similar to the catheter assembly 1100 (shown in FIG. 11). However, in contrast to the catheter assembly 1100, the catheter assembly 1200 includes a balloon 1208 surrounded by the splines 1204. The balloon 1208 can be selectively inflated to fill the space between the splines 1204. Notably, the balloon 1208 functions as an insulator and generally reduces energy loss compared to the catheter assembly 1200, and as a result, the damage size can be increased.

[0118] Each spline 1204 includes a proximal end 1210 coupled to the shaft 1202 and a distal end 1212 coupled to the shaft 1202. From the proximal end 1210 to the distal end 1212, the spline 1204 has an arcuate shape that extends radially outward.

[0119] In this embodiment, each spline 1204 includes a plurality of individual electrodes 1220. For example, each spline 1204 can include an elastic material (e.g., nitinol) covered by a polymer tube 1222, and the individual electrodes 1220 are attached to the outside of the polymer tube 1222. In the illustrated embodiment, each spline 1204 includes two electrodes 1220. Further, as shown in FIG. 12, the electrodes 1220 are generally disposed closer to the distal end 1212 than the proximal end 1210 so as to correspond to the portion of the spline 1204 that contacts the pulmonary vein 320.

[0120] Alternatively, each spline 1204 can include any suitable number and arrangement of electrodes 1220. For example, in some embodiments, each spline 1204 includes four electrodes 1220.

[0121] In this embodiment, alternating splines 1204 alternate in polarity. That is, the electrodes 1220 on a particular spline 1204 have the same polarity, but the electrodes 1220 on a particular spline 1204 have a different polarity than the electrodes 1220 on an adjacent spline 1204. Alternatively, any suitable polarization scheme may be used. During delivery, the spline 1204 can collapse toward the shaft 1202. Thereafter, to perform ablation, the spline 1204 is deployed to expand radially outward.

[0122] The splines 1204 may all be of the same length, or at least some of the splines 1204 may be of different lengths. Further, the insulating material (e.g., PET or PEBA material) on each spline 1204 may be of the same length, or at least some of the splines 1204 may have insulating materials of different lengths. Further, in some embodiments, the catheter assembly 1200 includes a distal electrode (not shown) disposed distally of the splines 1204. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1204), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1202).

[0123] Figure 13 is a perspective view of a catheter assembly 1300 of an alternative embodiment. The catheter assembly 1300 includes a shaft 1302 and a plurality of splines 1304 surrounding the distal portion 1306 of the shaft 1302. Each spline 1304 includes a proximal end 1310 coupled to the shaft 1302 and a distal end 1312 coupled to the shaft 1302. The spline 1304 extends radially outward from the proximal end 1310 to an inflection point 1314 and then extends radially inward to the distal end 1312.

[0124] The splines 1304 are made of an elastic material (e.g., nitinol) and function as relatively large electrodes. In this embodiment, the alternating splines 1304 alternate in polarity. That is, each positive spline 1304 is disposed between two negative splines 1304, and vice versa. Alternatively, any suitable polarization scheme may be used.

[0125] To control the ablation zones of each spline 1304, a portion of each spline 1304 may be covered with an insulating material 1320 (e.g., a heat shrink or polymer tube such as PET or PEBA), and the exposed portion of the spline 1304 functions as an electrode. In the embodiment shown in FIG. 13, the inflection points 1314 and the portion of the spline 1304 between the inflection point 1314 and the distal end 1312 are generally exposed, while the portion of the spline 1304 between the inflection point 1314 and the proximal end 1310 is generally insulated. As a result, the portion of the spline 1304 that contacts the pulmonary vein 320 is exposed. Alternatively, any suitable insulation configuration may be used.

[0126] As shown in FIG. 13, each spline 1304 includes a spreading member 1330. The spreading member 1330 includes a first end 1332, a second end 1334, a first branch 1336, and a second branch 1338. The first branch 1336 and the second branch 1338 extend away from each other from the first end 1332, then extend back towards each other and rejoin at the second end 1334.

[0127] The spreading member 1330 can be fabricated, for example, using laser cutting. In this embodiment, all of the spreading member 1330 is exposed (i.e., not covered with an insulating material). Alternatively, a portion of the spreading member 1330 may be covered with an insulating material.

[0128] By including the spreading member 1330 on the spline 1304, the range of the circumferential gap between the splines 1304 is reduced, making it easier to increase the damage volume. Additionally, additional splines 1304 may be included to further reduce the range of the circumferential gap.

[0129] In some embodiments, at least one of the splines 1304 includes a plurality of spreading members 1330 instead of a single spreading member 1330. Further, as shown in FIG. 13, the spreading members 1330 are longitudinally aligned with each other in the catheter assembly 1300. However, in some embodiments, at least some of the spreading members 1330 are longitudinally offset from each other.

[0130] Further, the spreading member 1330 is shown as having two branches 1336 and 1338 that are substantially equal in length, but the spreading member 1330 may have various numbers of branches and / or branches of non-uniform length. Further, in some embodiments, the spreading member 1330 may be formed from two separate splines 1304 instead of a single spline 1304 forming the spreading member 1330.

[0131] During delivery, the spline 1304 can collapse inwardly towards the shaft 1302. Further, when the spline 1304 collapses, the first branch 1336 and the second branch 1338 of each spreading member 1330 also collapse inwardly towards each other, reducing the overall profile of the catheter assembly 1300. Thereafter, to perform ablation, the spline 1304 is deployed such that the inflection point 1314 extends radially outward.

[0132] The splines 1304 may all be of the same length, or at least some of the splines 1304 may have different lengths. Further, the insulating material on each spline 1304 may be of the same length, or at least some of the splines 1304 may have insulating material of different lengths. Further, in some embodiments, the catheter assembly 1300 includes a distal electrode (not shown) disposed distally of the splines 1304. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1304), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1302).

[0133] FIG. 14 is a perspective view of a catheter assembly 1400 of an alternative embodiment. The catheter assembly 1400 includes a shaft 1402 and a plurality of splines 1404 surrounding a distal portion 1406 of the shaft 1402. However, in contrast to the catheter assembly 1300 (shown in FIG. 13), the catheter assembly 1400 includes a balloon 1408 surrounded by the splines 1404. The balloon 1408 can be selectively inflated to fill the space between the splines 1404. Notably, the balloon 1408 functions as an insulator and generally reduces energy loss compared to the catheter assembly 1300, and as a result, may increase the damage size.

[0134] Each spline 1404 includes a proximal end 1410 coupled to the shaft 1402 and a distal end 1412 coupled to the shaft 1402. The spline 1404 extends radially outward from the proximal end 1410 to a bend point 1414 and then extends radially inward to the distal end 1412.

[0135] The spline 1404 is made of an elastic material (e.g., nitinol) and functions as a relatively large electrode. In this embodiment, the alternating splines 1404 alternate in polarity. That is, each positive spline 1404 is disposed between two negative splines 1404, and vice versa. Alternatively, any suitable polarization scheme may be used.

[0136] To control the ablation zone of each spline 1404, a portion of each spline 1404 may be covered with an insulating material 1420 (e.g., a heat shrink or polymer tube such as PET or PEBA), and the exposed portion of the spline 1404 functions as an electrode. In the embodiment shown in FIG. 14, the inflection point 1414 and the portion of the spline 1404 between the inflection point 1414 and the distal end 1412 are generally exposed, while the portion of the spline 1404 between the inflection point 1414 and the proximal end 1410 is generally insulated. As a result, the portion of the spline 1404 that contacts the pulmonary vein 320 is exposed. Alternatively, any suitable insulation configuration may be used.

[0137] As shown in FIG. 14, each spline 1404 includes a spreading member 1430. The spreading member 1430 includes a first end 1432, a second end 1434, a first branch 1436, and a second branch 1438. The first branch 1436 and the second branch 1438 extend away from each other from the first end 1432, then extend back toward each other and rejoin at the second end 1434.

[0138] The spreading member 1430 can be fabricated, for example, using laser cutting. In this embodiment, all of the spreading member 1430 is exposed (i.e., not covered with an insulating material). Alternatively, a portion of the spreading member 1430 may be covered with an insulating material.

[0139] By including the spreading member 1430 on the spline 1404, the range of the circumferential gap between the splines 1404 is reduced, making it easier to increase the damaged volume. Further, additional splines 1404 may be included to further reduce the range of the circumferential gap.

[0140] In some embodiments, at least one of the splines 1404 includes a plurality of spreading members 1430 instead of a single spreading member 1430. Further, as shown in FIG. 14, the spreading members 1430 are longitudinally aligned with each other in the catheter assembly 1400. However, in some embodiments, at least some of the spreading members 1430 are longitudinally offset from each other.

[0141] During delivery, the splines 1404 can collapse inwardly towards the shaft 1402. Further, when the splines 1404 collapse, the first branch portion 1436 and the second branch portion 1438 of each spreading member 1430 also collapse inwardly towards each other, reducing the overall profile of the catheter assembly 1400. Thereafter, to perform ablation, the splines 1404 are deployed such that the inflection points 1414 extend radially outward.

[0142] All of the splines 1404 may be of the same length, or at least some of the splines 1404 may be of different lengths. Further, the insulating material on each spline 1404 may be of the same length, or at least some of the splines 1404 may have insulating material of different lengths. Further, in some embodiments, the catheter assembly 1400 includes a distal electrode (not shown) disposed distally of the splines 1404. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1404), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1402).

[0143] Figure 15 is a perspective view of a catheter assembly 1500 of an alternative embodiment. The catheter assembly 1500 includes a shaft 1502 and a plurality of splines 1504 surrounding the distal portion 1506 of the shaft 1502. Each spline 1504 includes a proximal end 1510 coupled to the shaft 1502 and a distal end 1512 coupled to the shaft 1502. The spline 1504 extends radially outward from the proximal end 1510 to an inflection point 1514 and then extends radially inward to the distal end 1512.

[0144] The splines 1504 are made of an elastic material (such as nitinol) and function as relatively large electrodes. In this embodiment, the alternating splines 1504 alternate in polarity. That is, each positive spline 1504 is disposed between two negative splines 1504, and vice versa. Alternatively, any suitable polarization scheme may be used.

[0145] To control the ablation zone of each spline 1504, a portion of each spline 1504 may be covered with an insulating material 1520 (such as a heat shrink or polymer tube like PET or PEBA), and the exposed portion of the spline 1504 functions as an electrode. In the embodiment shown in Figure 15, the inflection point 1514 and the portion of the spline 1504 between the inflection point 1514 and the distal end 1512 are generally exposed, while the portion of the spline 1504 between the inflection point 1514 and the proximal end 1510 is generally insulated. As a result, the portion of the spline 1504 that contacts the pulmonary vein 320 is exposed. Alternatively, any suitable insulation configuration may be used.

[0146] As shown in FIG. 15, each spline 1504 includes a tapered member 1530. The tapered member 1530 includes a first end 1532 and a second end 1534. The width of the tapered member 1530 is tapered outward along the first tapered portion 1540 from the first end 1532, the width is substantially constant along the intermediate portion 1542, and the width is tapered inward along the second tapered portion 1544 toward the second end 1534. In some embodiments, the tapered member 1530 includes only a single tapered portion.

[0147] The tapered member 1530 can be fabricated, for example, using laser cutting. In this embodiment, all of the tapered member 1530 is exposed (i.e., not covered with an insulating material). Alternatively, a portion of the tapered member 1530 may be covered with an insulating material. Further in this embodiment, the tapered member 1530 functions as a single electrode. Alternatively, the tapered member 1530 may be divided into a plurality of separate electrodes (including, for example, an insulating material and a ring electrode as needed).

[0148] By including the tapered member 1530 in the spline 1504, the range of the circumferential gap between the splines 1504 is reduced, making it easier to increase the damaged volume. Further, additional splines 1504 may be included to further reduce the range of the circumferential gap.

[0149] In some embodiments, at least one of the splines 1504 includes a plurality of tapered members 1530 instead of a single tapered member 1530. Further, as shown in FIG. 15, the tapered members 1530 are longitudinally aligned with each other in the catheter assembly 1500. However, in some embodiments, at least some of the tapered members 1530 are longitudinally offset from each other.

[0150] During delivery, the spline 1504 can collapse inward toward the shaft 1502. Thereafter, to perform ablation, the spline 1504 is deployed such that the inflection point 1514 extends radially outward.

[0151] The splines 1504 may all be of the same length, or at least some of the splines 1504 may have different lengths. Further, the insulating material on each spline 1504 may be of the same length, or at least some of the splines 1504 may have insulating material of different lengths. Further, in some embodiments, the catheter assembly 1500 includes a distal electrode (not shown) disposed distally of the splines 1504. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1504), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1502).

[0152] FIG. 16 is a perspective view of a catheter assembly 1600 of an alternative embodiment. The catheter assembly 1600 includes a shaft 1602 and a plurality of splines 1604 surrounding a distal portion 1606 of the shaft 1602. However, in contrast to the catheter assembly 1500 shown in FIG. 15, the catheter assembly 1600 includes a balloon 1608 surrounded by the splines 1604. The balloon 1608 can be selectively inflated to fill the space between the splines 1604. Notably, the balloon 1608 functions as an insulator and generally reduces energy loss compared to the catheter assembly 1500, resulting in an increased lesion size.

[0153] Each spline 1604 includes a proximal end 1610 coupled to the shaft 1602 and a distal end 1612 coupled to the shaft 1602. The spline 1604 extends radially outwardly from the proximal end 1610 to an inflection point 1614 and then extends radially inwardly to the distal end 1612.

[0154] The spline 1604 is made of an elastic material (e.g., nitinol) and functions as a relatively large electrode. In this embodiment, the alternating splines 1604 alternate in polarity. That is, each positive spline 1604 is disposed between two negative splines 1604, and vice versa. Alternatively, any suitable polarization scheme may be used.

[0155] To control the ablation zone of each spline 1604, a portion of each spline 1604 may be covered with an insulating material 1620 (e.g., a heat shrink or polymer tube such as PET or PEBA), and the exposed portion of the spline 1604 functions as an electrode. In the embodiment shown in FIG. 16, the inflection point 1614 and the portion of the spline 1604 between the inflection point 1614 and the distal end 1612 are generally exposed, while the portion of the spline 1604 between the inflection point 1614 and the proximal end 1610 is generally insulated. As a result, the portion of the spline 1604 that contacts the pulmonary vein 320 is exposed. Alternatively, any suitable insulation configuration may be used.

[0156] As shown in FIG. 16, each spline 1604 includes a tapered member 1630. The tapered member 1630 includes a first end 1632 and a second end 1634. The width of the tapered member 1630 is tapered outward along the first tapered portion 1640 from the first end 1632, the width is substantially constant along the intermediate portion 1642, and the width is tapered inward along the second tapered portion 1644 toward the second end 1634. In some embodiments, the tapered member 1530 includes only a single tapered portion.

[0157] The tapered member 1630 can be fabricated, for example, using laser cutting. In this embodiment, all of the tapered member 1630 is exposed (i.e., not covered with an insulating material). Alternatively, a portion of the tapered member 1630 may be covered with an insulating material. Further in this embodiment, the tapered member 1630 functions as a single electrode. Alternatively, the tapered member 1630 may be divided into a plurality of separate electrodes (e.g., including an insulating material and a ring electrode as needed).

[0158] Including the tapered member 1630 on the spline 1604 facilitates reducing the range of the circumferential gap between the splines 1604 and increasing the damaged volume. Further, additional splines 1604 may be included to further reduce the range of the circumferential gap.

[0159] In some embodiments, at least one of the splines 1604 includes a plurality of tapered members 1630 instead of a single tapered member 1630. Further, as shown in FIG. 16, the tapered members 1630 are longitudinally aligned with each other in the catheter assembly 1600. However, in some embodiments, at least some of the tapered members 1630 are longitudinally offset from each other.

[0160] During delivery, the splines 1604 can collapse inwardly towards the shaft 1602. Thereafter, to perform ablation, the splines 1604 are deployed such that the inflection point 1614 extends radially outward.

[0161] All of the splines 1604 may be of the same length, or at least some of the splines 1604 may have different lengths. Further, the insulating material on each spline 1604 may be of the same length, or at least some of the splines 1604 may have insulating materials of different lengths. Further, in some embodiments, the catheter assembly 1600 includes a distal electrode (not shown) disposed distally of the splines 1604. The distal electrode may be used to perform point ablation (e.g., by forming a bipolar between the distal electrode and one of the splines 1604), and / or may be used for visualization / mapping purposes (e.g., by using the distal electrode in combination with an electrode on the shaft 1602).

[0162] At least in part due to the length of the exposed portion of the spline, the catheter assembly described herein can form a lesion having a length in the range of about 1.0 to 1.5 cm in some embodiments. As a result, in contrast to lesions in at least some known systems (which may have a length of about 4 or 5 mm), the muscle of the lesion area is widened, which helps to prevent breakthrough. This is important because lesions are often non-uniform. Further, a larger lesion length results in ablation of a wider area of the pulmonary vein. This is advantageous because the pulmonary vein contains many transitional tissue fibers that can induce arrhythmias.

[0163] In the embodiments described herein, the spline is generally linear. However, the spline may have any suitable shape. For example, in some embodiments, the spline may have an S-shape, which can facilitate stress relaxation when the spline expands and contracts.

[0164] Furthermore, although the embodiments described herein are shown with a specific number of splines, those skilled in the art will understand that any suitable number of splines can be included. For example, the catheter assembly can include 4, 6, 8, 10, 12, 14, 16, 18, or 20 splines in some embodiments.

[0165] As described above, in a catheter assembly that includes a balloon surrounded by splines (and corresponding electrodes), the balloon functions as an insulator and generally reduces energy loss. This is because the electrodes mainly transmit energy from the balloon to the outside by the balloon, and as a result, the energy is mainly transmitted to the target tissue rather than the blood pool.

[0166] In PFA therapy, at least some known systems may generate microbubbles, which may be undesirable. However, it has been observed that as the current density at the electrodes increases, microbubble formation increases. Thus, reducing the current density generally reduces microbubble formation. In at least some of the embodiments described herein, (e.g., in embodiments where a relatively long exposed portion of the spline functions as an electrode,) the electrodes have a relatively large surface area. The larger this surface area, the lower the current density, and thus, (in addition to the more efficient energy delivery to the target tissue as described above,) microbubble formation is reduced.

[0167] One of ordinary skill in the art will understand that the various embodiments of the catheter assembly can be implemented independently of one another or in any suitable combination.

[0168] Furthermore, the catheter assemblies described herein can have any suitable dimensions. For example, in some embodiments, with the spline in an expanded configuration, the catheter assemblies described herein have a diameter in the range of about 28 - 35 mm. Alternatively, the catheter assemblies described herein can have a smaller diameter (e.g., in the range of about 8 - 10 mm).

[0169] For example, FIG. 17 is a perspective view of a catheter assembly 1700 of an alternative embodiment. The catheter assembly 1700 includes a shaft 1702 and a plurality of splines 1704 surrounding the distal portion 1706 of the shaft 1702. The catheter assembly 1700 also includes a balloon 1708 surrounded by the splines 1704. The balloon 1708 can be selectively inflated to fill the space between the splines 1704. Notably, the balloon 1708 functions as an insulator and generally can reduce energy loss, and as a result, increase the lesion size.

[0170] Compared with catheter assemblies 300, 400, 500, 600, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, catheter assembly 1700 may be smaller and have a more simplified design, and as a result, the manufacturing cost may be reduced. For example, in some embodiments, catheter assemblies 300, 400, 500, 600, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600 may have a diameter in the range of about 28-35 mm with the spline expanded to facilitate performing PVI. In contrast, with the spline 1704 expanded, catheter assembly 1700 may have a diameter in the range of about 8-10 mm (e.g., a diameter of 9 mm). Further, in the collapsed state, catheter assembly 1700 may be deliverable using a 7.5 French shaft.

[0171] Due to its small diameter, catheter assembly 1700 can be smaller and generate more focused damage. For example, catheter assembly 1700 can be used to treat the gaps remaining after performing PVI using any of catheter assemblies 300, 400, 500, 600, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600. Thus, catheter assembly 1700 can be used to supplement the procedures performed using catheter assemblies 300, 400, 500, 600, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600. As another example, catheter assembly 1700 can be used to treat other targets such as the posterior wall.

[0172] Simulations have revealed that catheter assembly 1700 generates damage substantially consistently regardless of the orientation of catheter assembly 1700 relative to the target tissue. For example, in the simulations, damage with a depth of at least 4 mm was achieved with the shaft 1702 at angles of about 10°, 45°, and 90° relative to the surface of the target tissue.

[0173] In the illustrated embodiment, each spline 1704 includes an exposed portion 1710 that functions as an electrode and an insulating portion 1712 proximal to the exposed portion 1710. In some embodiments, another insulating portion 1712 is included distal to the exposed portion 1710. Alternatively, this distal insulating portion 1712 may be omitted. The spline 1704 is shown as having a constant width, but those skilled in the art will understand that other spline shapes (e.g., tapered shapes, split shapes, etc.) may be used.

[0174] To perform ablation, a voltage (e.g., 1500 V) is applied to the catheter assembly 1700. Specifically, the voltage may be applied between the splines 1704 according to a bipolar approach. Alternatively, the voltage may be applied between one or more splines 1704 and a separate electrode (e.g., a body patch electrode) by a unipolar approach. Further, the voltage may be applied to the splines 1704 simultaneously or sequentially (e.g., via multiplexing).

[0175] The catheter assembly 1700 includes two splines 1704. Alternatively, more splines may be included. For example, FIG. 18 is a perspective view of an alternative embodiment catheter assembly 1800 that includes four splines 1804, and FIG. 19 is a perspective view of an alternative embodiment catheter assembly 1900 that includes six splines 1904. Except for the number of splines, the catheter assemblies 1800 and 1900 are substantially similar to the catheter assembly 1700.

[0176] The embodiments described herein provide a system and method for an electroporation catheter. An exemplary electroporation catheter includes a shaft and a plurality of splines that form a basket around a distal portion of the shaft, each spline extending between a proximal end coupled to the shaft and a distal end coupled to the shaft, and each spline of the plurality of splines comprising at least one energizable electrode. The electroporation catheter further includes a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixing the positions of the plurality of splines.

[0177] As described above, certain embodiments of the present disclosure have been described in some detail. However, those skilled in the art can make numerous modifications to the disclosed embodiments without departing from the spirit or scope of the present disclosure. All references to directions (e.g., upper, lower, above, below, left, right, leftward, rightward, upward, downward, vertical, horizontal, clockwise, and counterclockwise) are used only for identification purposes to assist the reader's understanding of the present disclosure and do not in particular impose limitations on the position, direction, or use of the present disclosure. References to coupling (e.g., attachment, connection, linkage, etc.) should be construed broadly and may include intermediate members between the connection of elements and relative movement between elements. Therefore, references to coupling do not necessarily imply that two elements are directly connected and in a fixed relationship with each other. It is intended that all matters included in the above description or shown in the accompanying drawings be construed as illustrative only and not limiting. Changes in details or structure can be made without departing from the spirit of the present disclosure as defined in the appended claims.

[0178] When introducing an element or a preferred embodiment thereof of the present disclosure, the articles "a", "an", "the", and "said" are intended to mean that one or more of the elements exist. The terms "comprising", "including", and "having" are intended to be inclusive and mean that additional elements other than the recited elements may exist.

[0179] Without departing from the scope of the present disclosure, various changes can be made to the above configuration. Therefore, all matters included in the above description or shown in the accompanying drawings are to be construed as illustrative and not in a limiting sense. The following items are elements described in the claims at the time of international filing. (Item 1) An electroporation catheter, comprising a shaft, and a plurality of splines forming a basket around a distal portion of the shaft, wherein each spline of the plurality of splines extends between a proximal end coupled to the shaft and a distal end coupled to the shaft, and each spline comprises at least one energizable electrode; the plurality of splines, and a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixation of the plurality of splines; the balloon. An electroporation catheter comprising the above. (Item 2) Each spline comprises a body made of an elastic conductive material, and an insulating material covering a part of the body, and at least one exposed portion of the body corresponds to the at least one selectively energizable electrode. The electroporation catheter according to Item 1. (Item 3) Each spline comprises at least one spreading member corresponding to the at least one energizable electrode, and the at least one spreading member comprises a first end, a second end, a first branch extending from the first end to the second end, and a second branch extending from the first end to the second end, the first branch and the second branch being spaced apart from each other. The electroporation catheter according to Item 1. (Item 4) Each spline comprises at least one tapered member corresponding to the at least one energizable electrode, and the at least one tapered member comprises a first end, a second end, and at least one tapered portion disposed between the first end and the second end. The electroporation catheter according to Item 1. (Item 5) The at least one tapered portion comprises a first tapered portion and a second tapered portion. The at least one tapered member further comprises an intermediate portion extending between the first tapered portion and the second tapered portion, and the intermediate portion has a constant width, the electroporation catheter according to item 4. (Item 6) The shaft an outer shaft element, and an inner shaft element extending through the outer shaft element, wherein a distal end of each of the splines is operably connected to a distal end of the inner shaft element, a proximal end of each of the splines is connected to a distal end of the outer shaft element, the inner shaft element being slidable relative to the outer shaft element to adjust an effective diameter of the basket formed by the plurality of splines, the inner shaft element; comprising the electroporation catheter according to item 1. (Item 7) When the inner shaft element is slid distally relative to the shaft element, the effective diameter decreases, When the inner shaft element is slid proximally relative to the shaft element, the effective diameter increases, the electroporation catheter according to item 6. (Item 8) The inner shaft element defines a central lumen, the central lumen being configured to receive at least one of a contrast agent, a mapping catheter, a guide wire, and a shape sensing fiber. the electroporation catheter according to item 6. (Item 9) A channel is defined between the inner shaft element and the outer shaft element, the channel being in fluid communication with the interior of the balloon to facilitate selective inflation of the balloon using fluid, the electroporation catheter according to item 6. (Item 10) The electroporation catheter according to item 1, wherein alternating splines have electrodes with alternating polarities. (Item 11) An electroporation system, a generator, and a catheter coupled to the generator, the catheter a handle, a shaft extending distally from the handle, and a plurality of splines forming a basket around a distal portion of the shaft, each of the plurality of splines extending between a proximal end coupled to the shaft and a distal end coupled to the shaft, each of the splines comprising at least one energizable electrode, the plurality of splines; A balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate fixing the positions of the plurality of splines, An electroporation system comprising. (Item 12) Each of the splines, A body made of an elastic conductive material, An insulating material covering a part of the body, At least one exposed portion of the body corresponds to the at least one selectively energizable electrode, The electroporation system according to Item 11. (Item 13) Each spline includes at least one spreading member corresponding to the at least one energizable electrode, The at least one spreading member, A first end, A second end, A first branch portion extending from the first end to the second end, A second branch portion extending from the first end to the second end, the first branch portion and the second branch portion being spaced apart from each other, the second branch portion, The electroporation system according to Item 11, comprising. (Item 14) Each spline includes at least one tapered member corresponding to the at least one energizable electrode, The at least one tapered member, A first end, A second end, At least one tapered portion disposed between the first end and the second end, The electroporation catheter according to Item 11, comprising. (Item 15) The at least one tapered portion includes a first tapered portion and a second tapered portion, The at least one tapered member further includes an intermediate portion extending between the first tapered portion and the second tapered portion, the intermediate portion having a constant width, the electroporation system according to Item 14. (Item 16) The shaft, An outer shaft element, An inner shaft element extending through the outer shaft element, The distal end of each spline is operably connected to the distal end of the inner shaft element, The proximal end of each spline is connected to the distal end of the outer shaft element, The inner shaft element is slidable relative to the outer shaft element to adjust the effective diameter of the basket formed by the plurality of splines, the inner shaft element, The electroporation system according to Item 11, comprising. (Item 17) When the inner shaft element is slid distally relative to the shaft element, the effective diameter decreases, The electroporation system according to item 16, wherein when the inner shaft element is slid proximally relative to the shaft element, the effective diameter increases. (Item 18) The inner shaft element defines a central lumen, The central lumen is configured to receive at least one of a contrast agent, a mapping catheter, a guide wire, and a shape sensing fiber. The electroporation system according to item 16. (Item 19) A channel is defined between the inner shaft element and the outer shaft element, The electroporation catheter according to item 16, wherein the channel is in fluid communication with the interior of the balloon to facilitate selective inflation of the balloon using fluid. (Item 20) A method of assembling an electroporation catheter, comprising: providing a shaft; coupling a plurality of splines to the shaft to form a basket around a distal portion of the shaft, wherein each spline of the plurality of splines extends between a proximal end coupled to the shaft and a distal end coupled to the shaft; each spline includes at least one energizable electrode; said forming step; disposing a balloon within the basket formed by the plurality of splines, said balloon being selectively inflatable to facilitate fixation of the plurality of splines; said disposing step;

Claims

1. An electroporation catheter, comprising: a shaft; a plurality of splines forming a basket around a distal portion of the shaft, each spline of the plurality of splines extending between a proximal end coupled to the shaft and a distal end coupled to the shaft; each spline comprising at least one energizable electrode; each spline further comprising: a first tapered portion extending distally from a proximal end of a tapered member and tapering such that a width thereof increases in a distal direction; an intermediate portion having a constant width and extending distally from the first tapered portion; a second tapered portion extending distally from the intermediate portion toward a distal end of the tapered member and tapering such that a width thereof decreases in a distal direction, the intermediate portion having an arcuate shape and curving radially outward between the first tapered portion and the second tapered portion; the plurality of splines comprising a single tapered member; a balloon disposed within the basket formed by the plurality of splines and selectively inflatable to facilitate fixing the positions of the plurality of splines; the electroporation catheter.

2. Each spline comprises: a body comprising an elastic conductive material; an insulating material covering a part of the body; at least one exposed portion of the body corresponding to the at least one selectively energizable electrode. The electroporation catheter according to claim 1.

3. The electroporation catheter according to claim 1, wherein the intermediate portion of each spline is located closer to the distal end than to the proximal end of the spline.

4. The electroporation catheter according to claim 1, wherein a first distance between a proximal end of the tapered member and a proximal end of a corresponding spline is greater than a second distance between a distal end of the tapered member and a distal end of the corresponding spline.

5. The shaft comprises: an outer shaft element; an inner shaft element extending through the outer shaft element, wherein the distal end of each spline is operably connected to the distal end of the inner shaft element, and the proximal end of each spline is connected to the distal end of the outer shaft element. ​ The inner shaft element is slidable relative to the outer shaft element to adjust the effective diameter of the basket formed by the plurality of splines, the inner shaft element, An electroporation catheter according to claim 1, comprising.

6. When the inner shaft element is slid distally relative to the outer shaft element, the effective diameter decreases, An electroporation catheter according to claim 5, wherein when the inner shaft element is slid proximally relative to the outer shaft element, the effective diameter increases.

7. The inner shaft element defines a central lumen, The central lumen is configured to receive at least one of a contrast agent, a mapping catheter, a guide wire, and a shape sensing fiber. An electroporation catheter according to claim 5.

8. A channel is defined between the inner shaft element and the outer shaft element, The electroporation catheter according to claim 5, wherein the channel is in fluid communication with the interior of the balloon to facilitate selective inflation of the balloon using fluid.

9. The electroporation catheter according to claim 1, wherein the alternating splines have electrodes with alternating polarities.

10. An electroporation system, A generator, A catheter coupled to the generator, comprising, The catheter is, A handle, A shaft extending distally from the handle, A plurality of splines forming a basket around a distal portion of the shaft, Each spline of the plurality of splines extends between a proximal end coupled to the shaft and a distal end coupled to the shaft, Each spline comprises at least one energizable electrode, Each spline further, A first tapered portion extending distally from the proximal end of the tapered member and inclined so that the width expands in the distal direction, An intermediate portion having a constant width and extending distally from the first tapered portion, A second tapered portion extending distally from the intermediate portion toward the distal end of the tapered member and inclined so that the width decreases in the distal direction, wherein between the first tapered portion and the second tapered portion, the intermediate portion has an arc shape and curves radially outward, the second tapered portion. a single tapered member, and the plurality of splines, a balloon disposed within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate securing the positions of the plurality of splines, An electroporation system comprising.

11. Each of the splines a body comprising an elastic conductive material, an insulating material covering a part of the body, at least one exposed portion of the body corresponds to the at least one selectively energizable electrode, The electroporation system according to claim 10.

12. The intermediate portion of each spline is located closer to the distal end than the proximal end of the spline. The electroporation system according to claim 10.

13. A first distance between the proximal end of the tapered member and the proximal end of the corresponding spline is greater than a second distance between the distal end of the tapered member and the distal end of the corresponding spline. The electroporation system according to claim 10.

14. The shaft an outer shaft element, an inner shaft element extending through the outer shaft element, the distal end of each spline is operably connected to the distal end of the inner shaft element, the proximal end of each spline is connected to the distal end of the outer shaft element, the inner shaft element is slidable relative to the outer shaft element to adjust an effective diameter of the basket formed by the plurality of splines, the inner shaft element, An electroporation system according to claim 10, comprising.

15. When the inner shaft element is slid distally relative to the outer shaft element, the effective diameter decreases, When the inner shaft element is slid proximally relative to the outer shaft element, the effective diameter increases. The electroporation system according to claim 14.

16. The inner shaft element defines a central lumen, the central lumen is configured to receive at least one of a contrast agent, a mapping catheter, a guide wire, and a shape sensing fiber, The electroporation system according to claim 14.

17. A channel is defined between the inner shaft element and the outer shaft element, The electroporation system according to claim 14, wherein the channel is in fluid communication with the interior of the balloon to facilitate selective inflation of the balloon using fluid.

18. A method of assembling an electroporation catheter, comprising: providing a shaft; coupling a plurality of splines to the shaft to form a basket around a distal portion of the shaft, each of the plurality of splines extending between a proximal end coupled to the shaft and a distal end coupled to the shaft; each of the splines comprising at least one energizable electrode; each of the splines further comprising: a first tapered portion extending distally from a proximal end of a tapered member and tapering such that the width increases in the distal direction; an intermediate portion having a constant width and extending distally from the first tapered portion; a second tapered portion extending distally from the intermediate portion toward the distal end of the tapered member and tapering such that the width decreases in the distal direction, the intermediate portion having an arcuate shape and curving radially outward between the first tapered portion and the second tapered portion; said forming step comprising a single tapered member comprising: placing a balloon within the basket formed by the plurality of splines, the balloon being selectively inflatable to facilitate securing the plurality of splines in position; a method comprising:

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