WO2024216286A2

WO2024216286A2 - Systems and methods for pulsed field ablation

Info

Publication number: WO2024216286A2
Application number: PCT/US2024/024678
Authority: WO
Inventors: Claudio Argento; Alejandro Rendon SANCHEZ; Tom Saul; Jonah Lepak
Original assignee: Shifamed Holdings LLC
Current assignee: Shifamed Holdings LLC
Priority date: 2023-04-14
Filing date: 2024-04-15
Publication date: 2024-10-17
Anticipated expiration: 2025-10-14
Also published as: WO2024216286A3

Abstract

The present technology relates to pulsed field ablation (PFA) and associated systems and methods. Embodiments of the present disclosure include a PFA system that is delivered via a low-profile catheter. The PFA catheter is formed to provide a flexible, adaptive ablation tool under robotic control for targeted and precise delivery of energy to selected tissue regions. This enables enhanced tissue targeting and continuity of generated lesions. The ablation may be delivered by selected pairs of electrodes via, for example, electric pulses.

Description

SYSTEMS AND METHODS FOR PULSED FIELD ABLATION

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/459,555, filed April 14, 2023, and U.S. Provisional Patent Application No. 63/583,675, filed September 19, 2023, both of which are incorporated by reference herein in their entireties.

TECHNICAL FIELD

[0002] The present technology relates to systems and methods for pulsed field ablation.

BACKGROUND

[0003] Attempts at addressing rhythm disturbances in the heart have included selective tissue (e.g., cell) destruction within a region of that is triggering the arrhythmia. Some arrhythmias are generated at a discrete site, such as atrioventricular (AV) nodal reentry or tachycardias associated with Wolff-Parkinson- White syndrome, while more complex arrhythmias including atypical atrial flutter, atrial fibrillation, and ventricular tachycardia. A leading approach in treatment of arrhythmias is tissue ablation, in which the cells within and/or adjacent a target area are destroyed to disrupt or abrogate errant signals transmitted through this region. Conventional approaches to tissue disruption include use of radiofrequency ablation (RFA) to form lesions at the targeted locations. RFA uses heat to destroy the cells at the target location. One problem with RFA is that it is difficult to control the dosage of heat to destroy the target tissue without negatively impacting/destroying adjacent tissues (e.g., esophagus, phrenic nerve). Injury to adjacent tissues presents patient risks that include diaphragm paralysis, atrioesophageal fistula, and pulmonary vein stenosis.

[0004] More recently, pulsed field ablation (PF A) is being increasingly investigated as an alternative approach to lesion generation, with the goal of increasing the specificity of treatment for the affected tissue and improving safety for the patient. PFA includes delivery of non-thermal energy through application of trains of high-voltage, short-duration electric pulses to kill target cells. There remains a need to improve specificity in target tissue treatment while sparing adjacent tissues. There also remains a need to provide feedback on the efficacy of the treatment, e.g., via electroanatomic mapping (EAM), preferably intra- and/or para-procedurally. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed on illustrating clearly the principles of the present technology. Furthermore, components can be shown as transparent in certain views for clarity of illustration only and not to indicate that the component is necessarily transparent. Components may also be shown schematically.

[0006] FIG. 1A depicts an exemplary configuration of a PFA catheter during a PFA procedure targeting tissues adjacent the pulmonary veins in accordance with embodiments of the present technology.

[0007] FIG. IB depicts an exemplary schematic system architecture for a robotically controlled PFA catheter configured in accordance with embodiments of the present technology.

[0008] FIGS. 2A 2D depict exemplary embodiments of components of a PFA catheter that provide varied electrode arrangements within an ablation and tissue measurement portion of the PFA catheter in accordance with embodiments of the present technology.

[0009] FIGS. 3A 3D depict exemplary embodiments of a PFA catheter having independently positionable conductor and/or electrode groups in accordance with embodiments of the present technology.

[0010] FIG. 4 depicts exemplary embodiments of an alternative electrode configuration that comprises a spring conformation in accordance with embodiments of the present technology.

[0011] FIGS. 5 A 5C depict exemplary internal electrodes arranged within a catheter having a permeable or porous membrane conductive portion in accordance with embodiments of the present technology.

|0012] FIGS. 6A 6C depict exemplary anchoring embodiments of a PFA catheter including an array of conductive surfaces arranged in a (e.g., flexible) coil or lasso configuration in accordance with embodiments of the present technology.

[0013] FIGS. 7A and 7B depict exemplary anchoring embodiments of a PFA catheter including an array of conductive surfaces arranged in a (e.g., flexible) angled (e.g., paddle) arrangement and carried on a guidewire in accordance with embodiments of the present technology. [0014] FIGS. 8A -8C depict exemplary anchoring and tissue interacting embodiments of a robotic PFA catheter including electrode surfaces arranged on an ablation member and carried on a guidewire in accordance with embodiments of the present technology.

[0015] FIG. 9 depicts exemplary tissue ablation operations in accordance with embodiments of the present technology.

[0016] FIG. 10 depicts an exemplary expandable electrode arrangement for a PFA catheter configured in accordance with embodiments of the present technology.

[0017] FIG. 11 depicts an exemplary expandable electrode arrangement for a PFA catheter configured in accordance with additional embodiments of the present technology.

[0018] FIG. 12 depicts an exemplary expandable electrode arrangement for a PFA catheter configured in accordance with further embodiments of the present technology.

[0019] FIG. 13 depicts exemplary expandable electrode array configurations formed by wireform and/or wire mesh configured in accordance with embodiments of the present technology.

[0020] FIGS. I 4A- I4D depict an exemplary expandable electrode arrangement for a PFA catheter configured in accordance with embodiments of the present technology.

DETAILED DESCRIPTION

[0021] The present technology is directed to pulse field ablation (PFA) and associated systems and methods. Embodiments of the present disclosure include a PFA system that is delivered to a target treatment site within a patient via a low-profile catheter, for example, one that is from about 6Fr to about 16Fr in size. The PFA catheter is formed to provide a flexible, adaptive ablation tool for targeted and precise delivery of energy to selected tissue regions of the patient. This enables enhanced tissue targeting and continuity of generated lesions. The ablation may be delivered by (selected) pairs of electrodes, for example, via electric pulses.

[0022] In some embodiments, the electrode pairs are arranged at a fixed distance with respect to one another. In alternative embodiments a separation distance between the electrode pairs can be varied (e.g., intraprocedurally). The electrodes may be arranged at a distal portion of the flexible PFA catheter. The catheter can be conformable and/or steerable. In some embodiments, the primary electrodes are movable. In some embodiments, the PFA catheter is robotically steered and/or controlled. In some embodiments, the position and position history of PFA catheter is (e.g., robotically) tracked. In some embodiments, the tracking data is used to update a representation of the patient's anatomy, for example to indicate regions of tissue that are estimated/measured to have been successfully treated. In some embodiments, the (e.g., two, primary) electrodes are interfaced with a structure (e.g., body of PFA catheter, or portion therein) that constrains movement of the electrodes therein to a predefined path (e.g., robotically controlled). In further embodiments, the structure comprises a means of passing energy from the primary electrodes to the target tissue. In some embodiments, the structure comprises a (e.g., fixed) set of secondary electrodes, which in turn interface with the target tissue via the PFA catheter.

[0023] In some embodiments, the structure comprises a porous region(s) and/or holes in the outer catheter. In some embodiments, the catheter is saturated with a conductive fluid, is filled/partially filled with a conductive fluid, or is fluidically coupled to a conductive fluid source and operable to receive the fluid. In some embodiments, the fluid is more conductive than blood or the tissue to be ablated. In some embodiments, the fluid contains ions which enhance the effects of irreversible electroporation (IRE), such as for example calcium ions. In some embodiments, the secondary electrodes are addressable (e.g., via electric coupling with primary electrodes) in pairs. In some embodiments, the interfacing structure is anchored to a physiological surface via an anchor, for example a portion of an atrium, an ostia, or a portion of a pulmonary vein. In some embodiments, the anchor can (e.g., additionally) be used as an electrode.

[0024] In some embodiments, individual pairs of a plurality of pairs of electrodes at the distal portion of the PFA catheter can be selectively activated. Selective activation of pairs of electrodes, optionally in combination with the flexible/conformable configuration of the distal portion of the PFA catheter, increases flexibility and precision with which a clinician is enabled to treat the tissue addressed by individual pulses of the ablation catheter. Targeted, pairwise activation further enables a reduction in (total) applied voltage delivered to the tissues of the body (per pulse), for example reduced as compared to alternative systems that activate a (substantial) totality of available electrodes during each pulse of treatment. Reduced applied voltage beneficially reduces gas generation in surrounding blood/tissue, as well as incidence of induced muscle spasms or tissue shock. Generally, the use of smaller, more closely spaced electrodes reduces an applied voltage required to achieve a threshold therapeutic level at the tissue.

[0025] In some embodiments, the electrodes deliver high amplitude electrical pulses (e.g., each lasting about a microsecond) that ablate the myocardium via electroporation of the sarcolemma membrane without measurable tissue heating. Unlike the esophagus, phrenic nerves, pulmonary veins, and coronary arteries, the myocardium is particularly susceptible to irreversible injury. In some embodiments, the ablation pulse waveform includes multiple variable components that can affect ablation efficacy, and thus each proprietary system has unique properties that cannot be generalized to other systems.

[0026] FIG. 1A depicts an exemplary configuration of a PFA catheter 115 during a PFA procedure targeting ostia tissues 130 adjacent the pulmonary veins 135. The PFA catheter 115 can be steerable. The PFA catheter 115 can be guided and/or steered in a translumenal approach through the inferior vena cava 100, across the right atrium (RA) and through the septal wall 113, into the left atrium (LA). In some embodiments, a distal (e.g., electrode carrying) portion 120 of the PFA catheter is shape set and/or actively steered (e.g., actuated) to assume a preset shape upon delivery. As shown in FIG. 1, the PFA catheter 115 includes an anchor portion (e.g., shaft) 125 that stabilizes and/or secures a distal portion of the PFA catheter 115 with respect to the target tissue during operation. In some embodiments, the anchor portion 125 extends (e.g., distally) beyond an ablation (electrode-carrying) portion 120 (e.g., tool) of the PFA catheter 115. The anchor 125 can comprise, for example, a balloon, a stent, a wireform, a mesh, a J tip, or a pigtail (e.g., guidewire). The anchor 125 can be placed distal to the tool (e.g., electrode array) portion 120, for example in the pulmonary veins 135. The anchor 125 can form a stable fixation and/or rotation axis for placement and movement of electrodes.

[0027] An exemplary ablation procedure includes the following operations: (a) placing a guidewire, (b) placing a PFA anchor, (c) activate (pair of) electrodes, (d) (e.g., robotically) move the electrodes to a new position, and (e) repeating steps (c) and (d) until ablation has been performed at all targeted tissue locations. For example, for pulmonary vein isolation, steps (c) and (d) are alternated until a complete revolution has been performed by the electrodes. In some embodiments, the voltage applied by the electrodes is varied according to (e.g., considering) the step size of electrode movement between sequential activations. Generally, the applied voltage can be reduced when the incremental movements (e.g., between sequential activations) are small. Conversely, the applied voltage may be increased when the incremental movements (e.g., between sequential activations) are larger. Various embodiments of the anchor portion and ablation portion are described in further detail below.

[0028] In several embodiments of the present technology, a PFA catheter can include electrodes that are movable within a lumen of a catheter that has (positionally) fixed conductive surfaces on an external surface thereof. The fixed conductive surface(s) can be free of any electrical connection, either proximally or between members. The utility of the fixed conductive surfaces for ablation or measurement operation relies on the electrical connections of the movable electrodes that are interfaceable therewith. This can advantageously reduce complexity of the ablation system, reduce a required profile of the catheter (e.g., Fr size), improve flexibility of the catheter, and reduce a potential of electrical crosstalk between elements.

[0029] As noted above, in some embodiments the PFA catheter is robotically steered and/or controlled. Robotically scanned/moved includes steered, configured (strait to lasso), electrode position control, electrode selection control, and/or configuration locking. The robotic control can comprise open loop control or closed loop control. Control can comprise consideration of data generated by internal sensor and/or data from external imaging or mapping systems. As schematically depicted in FIG. IB, an ablation system configured in accordance with embodiments of the present technology includes a controller 102 operably coupled to an ablation tool (e.g., member) 110. In FIG. IB, the controller 102 controls and/or receives data associated with (a) a robotic controller 104, (b) a pulse generator 106, and (c) sensor measurements 108. The controller 102 communicates with the ablation tool 110 to control and read (e.g., determine) signals corresponding to voltage(s) 112 that are applied to ablation electrodes, positioning 114 of electrodes within the ablation tool 110, and activation and/or modality of operation 116 of electrodes. The control architecture depicted in FIG. IB can be used with each of the embodiments described herein, along with other suitable systems configured in accordance with the present technology.

[0030] FIGS. 2A 2D depict exemplary embodiments of components of a PFA catheter that provide varied electrode arrangements within an ablation portion 220 of the PFA catheter (e.g., FIG. 2A). As depicted in FIG. 2A, a conductive element group 200 comprises a pair of conductive surfaces — that correspond to or couple with — electrodes. The conductor group 200 can comprise pairs of conductive surfaces that have separation (inter-electrode) distance D (examples provided in Table 1 below). In some embodiments, at least two pairs of electrodes are similarly spaced at a consistent (e.g., fixed) distance D. In some embodiments, at least two pairs of electrodes are spaced to have different inter-electrode distances (e.g., DI and D2). In some embodiments, an interelectrode distance D can be varied, e.g., intraprocedurally. FIG. 2B depicts an example of a PFA catheter 250 having a pair of electrodes that are formed to be positioned at various axial positions along the catheter lumen 280. In the example of FIG. 2B, a first electrode 265 is positioned at a distal end of the PFA catheter 250. The first electrode 265 is coupled via a first wire 255 to a proximal control (e.g., robot controller 104 of FIG. IB). A second electrode 270 is positioned proximally with respect to the first electrode 265. The second electrode 270 is coupled via a second wire 260 to the proximal control (or alternatively, to a second proximal control). As shown in FIG. 2B and FIG. 2C, the first electrode 265 and the second electrode 270 are formed to define a (e.g., common) lumen 292c and 294c (FIG. 2C), respectively, which is shaped and sized to accommodate a guidewire 290 (FIG. 2B) therein.

[0031] FIG. 2C depicts an example of four movable electrodes according to embodiments of the present technology. As shown in FIG. 2C, the first electrode 292 and the second electrode 294 each comprise (radially) outer conductive surfaces 285 and (radially) inner insulation surfaces 292d. The first electrode 292 includes a (e.g., first) wire termination 292b that is coupled to the first electrode 292 via a projected connection 292a. The second electrode 294 includes a (e.g., second) wire termination 294b that is coupled to the second electrode 294 via a projected connection 294a, and further includes a (e.g., first) wire lumen 294d shaped and sized to accommodate the first wire (e.g., first wire 255 of FIG. 2B) passing therethrough. Additional electrodes are formed similarly with additional wire lumens for passing wires associated with neighboring electrodes. A third electrode 296 comprises a connection 296a, a wire termination 296b, a guidewire lumen 296c, and electrode wire lumens 296d. A fourth electrode 298 comprises a connection 298a, a wire termination 298b, a guidewire lumen 298c, and electrode wire lumens 298d.

[0032] Referring to the various embodiments of PFA catheter systems disclosed herein together, a PFA catheter system can deliver PFA and/or radio frequency ablation (RFA) across a target ablation site (e.g., the left pulmonary vein, the right pulmonary vein) of a patient. According to embodiments of the present disclosure, a PFA catheter system can also include electroanatomic mapping (EAM). Data provided by EAM can include, for example, chamber reconstruction, tagging of selected anatomic landmarks and ablation lesions, display of diagnostic and mapping catheters (e.g., without use of fluoroscopy), activation mapping, and/or voltage (or scar) mapping. The EAM can include a record of intracardiac electrical activation in relation to anatomic location in a cardiac chamber of interest, during arrhythmia mapping. In some embodiments, EAM is provided by (e.g., robotically) scanning selected electrodes across tissue of interest. Robotic control of electrode position enables precise and repeatable placement of the ablation surfaces, and the interrogation (e.g., electrode) surfaces. This precision and repeatability are further expected to enable the device to revisit prior-treated areas to query the result (e.g., effectiveness) of treatment. Semiautomated EAM is also expected to reduce the time of mapping (e.g., to between about one minute and three minutes) and minimize human error.

[0033] The EAM can be used to generate a model, including a representation of the ablated tissue (e.g., map ablation lines). In some embodiments, spectral impedance matching can be performed by measuring the impedance between the PFA anchor, the electrodes, and the tissue interposed therebetween. Such measurements can also provide data on the ablation progress/completeness.

Table 1 : PFA Catheter parameters

[0034] In some embodiments, the same electrode surfaces are used for the ablation and the interrogation operations (via control of operation modality). In some embodiments, discrete (e.g., sets of) electrodes are used for ablation and interrogation. The particular electrodes used for each modality can be controlled such that sensing electrodes are operated simultaneously with and/or following energizing electrodes. FIG. 2D, for example, provides an example of EAM combined with PFA operations. As shown in FIG. 2D, the electrodes can be controllably and selectively moved amongst a plurality of positions (e.g., 230 and 240) that correspond to positions of (e.g., external) conductive surfaces 210 (e.g., electrodes) disposed on an external periphery of the PFA catheter 220a. For example, a set of (internal) conductive elements 215 and 225 can be moved proximally and/or distally within the lumen of the PFA catheter to couple with corresponding external conductive surfaces. In one example, the conductive elements 215 can be energized to generate an electric field to treat target tissue(s) adjacent to the activated external electrodes, while conductive elements 225 are used in an impedance measurement mode to detect the impedance of tissues for use in estimating a treatment effect. Following the first treatment of ablation pulse(s) and tissue measurements at position 230, the set of electrodes are moved to a second position 240 for a subsequent tissue treatment. At least one of (a) the subsequent position 240 and (b) the energy of the subsequent pulse can be made considering the measured tissue temperature and/or impedance from one or more prior tissue treatments. In this manner, the applied electric field can be targeted and (re-) positioned to precisely treat selected tissue regions.

[0035] FIGS. 3A 3D depict exemplary embodiments of a PFA catheter having independently positionable conductor and/or electrode groups. In the embodiment depicted in FIG. 3A, a first electrode 392 is positioned at a distal end of the group. The first electrode 392 is coupled via a first wire 305 to a proximal control (e.g., robotic controller 104 of FIG. IB). A second electrode 394is positioned proximally with respect to the first electrode 392. The second electrode 394 is coupled via a second wire 310 to the proximal control (or alternatively, to a second proximal control). As shown in FIGS. 3A-3D, the first and second electrodes 392 and 394 are formed to define a (e.g., common) lumen (e.g., similar to or identical to lumens 292c and 294c of FIG. 2C) that is shaped and sized to accommodate a guidewire 320 therein. The first and second electrodes 392 and 394 are independently translatable along the guidewire 320 to be selectively positioned at target axial positions of the PFA catheter, and with various selected separation distances. FIGS. 3A 3D depict exemplary variations in separation distances 315, 325, 335, and 345 of the first and second electrodes 392 and 394. In this manner, the PFA catheter can maintain a given configuration or geometry, while the position/location of applied voltage can be changed by movement of the electrode group along the axial length of the PFA catheter.

[0036] FIG. 4 depicts exemplary embodiments of electrode configurations that comprises a spring conformation. An electrode formed to include a spring element can advantageously adapt in size, for example to improve contact with tissues of different geometries. In some embodiments, the electrode can be formed to integrally define a (e.g., wire and/or guidewire) lumen 496, which is coupled to an outer conductive surface 485. In this manner, the PFA catheter can maintain a given configuration or geometry, while the position/location of applied voltage can be changed by movement of the electrode group along the axial length of the PFA catheter. The electrode configurations of FIG. 4 can (alternatively) be used in each electrode embodiments described herein.

[0037] FIGS. 5 A 5C depict exemplary internal electrodes arranged within a catheter having a conductive region that comprises a permeable membrane portion. In the embodiment of FIG. 5 A, an electrode-cany ing portion of a PFA catheter 515 is depicted. As shown, the portion of the PFA catheter includes a centrally located guidewire lumen 502, a wire lumen 504, a wire 508, an insulation portion 506, and an electrode portion 510 (e.g., generally similar to electrodes as described in FIGS. 2A-2D and 3 A - 3D). The PFA catheter further includes a permeable portion 520 adjacent to the electrode portion. The permeable portion 520 comprises or is adapted to contain a material (e.g., fluid) that passes electric field therethrough. The permeable membrane 520 can be placed at selected portions of the PFA catheter 515, for example can extend axially along a portion 535 of the PFA catheter (e.g., FIGS. 5B and 5C). In operation, as an electrode group 525 is moved from a first position 540 to a second position 550 along a guidewire 530 within the PFA catheter 515 (or within the outer electrode-carrying portion), the membrane region 535 is configured to pass an electric field generated by the electrode group 525 to target tissue adjacent that portion of the PFA catheter 515. In this manner, the PFA catheter 515 can maintain a given configuration or geometry, while the position/location of applied voltage can be changed by movement of the electrode group along the axial length of the PFA catheter. The permeable portion 520 effectively forms a continuum of addressable positions, in comparison to a set of discretely addressable positions. In this fashion the electrodes can be pulsed continuously while being moved stepwise or continuously, either manually or under robotic control. This can be done while maintaining the PFA catheter 515 in a stationary position and/or configuration within patient anatomy.

[0038] FIGS. 6A-6C depict exemplary anchoring embodiments of a PFA catheter including an array of electrode surfaces arranged in a (e.g., flexible) coil or lasso configuration. In some embodiments, the "lasso" comprises a backbone structure, which enables the catheter to be introduced in a flexible configuration and actuated to stiffen into the lasso configuration. The backbone structure can comprise (e.g., laser cut) PEEK or Nitinol. As shown in FIG. 6A-6C, the PFA catheter 615 includes an anchor 620 disposed on a centrally located guidewire, located distal to a PFA tool 610 (e.g., the coiled array of electrodes). The PFA tool 610 can be any PFA electrode arrangement as described by embodiments herein. As shown in FIGS. 6B and 6C, the guidewire has been advanced into a pulmonary vein and the PFA catheter has been anchored therein. The PFA anchor can be any PFA anchor arrangement as described by embodiments herein. In some embodiments, the anchor is self-centering, for example centers the guidewire within the vessel, and the PFA tool with respect to the perimeter of the target tissue (e.g., the ostia). In the example of FIGS. 6A 6C, the flexible PFA catheter encircles (forms a loop) and conforms to the tissue to provide good tissue contact with the conductive surfaces of the PFA catheter. [0039] FIGS. 7A and 7B depict exemplary anchoring embodiments of a PFA catheter 715 including an ablation member 710 carrying an array of electrode surfaces arranged in a (e.g., flexible) angled (e.g., paddle) arrangement and carried on a guidewire. The PFA tool can be any PFA electrode arrangement as described by embodiments herein. As shown in FIG. 7B, the guidewire has been advanced into a pulmonary vein and the PFA catheter has been anchored therein by anchor 720. The PFA anchor can be any PFA anchor arrangement as described by embodiments herein. In some embodiments, the anchor is self-centering, for example centers the guidewire within the vessel, and the PFA tool with respect to the perimeter of the target tissue (e.g., the ostia). In the example of FIGS. 7A and 7B, the electrode array of the PFA catheter conforms to the tissue in a generally linear arrangement to provide good tissue contact with the conductive surfaces of the PFA catheter. According to embodiments of the present disclosure, tissue ablation comprises iterative and sequential administration of applied voltage at the conductive surfaces, followed by incremental movement of the electrode arrangement, until all targeted tissue is ablated.

[0040] FIGS. 8A-8C depict exemplary anchoring embodiments of a PFA catheter 815 including an ablation member 810 comprising at least a pair of electrode surfaces arranged in a (e.g., flexible) angled (e.g., paddle) arrangement and carried on a guidewire. As shown in FIGS. 8A and 8B, the guidewire has been advanced into a pulmonary vein and the PFA catheter has been anchored therein by catheter anchor 820. The anchor 820 can be any PFA anchor arrangement as described by embodiments herein. In some embodiments, the anchor is self-centering, for example centers the guidewire within the vessel, and the PFA tool with respect to the perimeter of the target tissue (e.g.. the ostia). In the example of FIGS. 8A-8C, the electrode array of the PFA catheter conforms to the tissue in a generally pairwise arrangement to provide good tissue contact w ith the conductive surfaces of the PFA catheter while minimizing a footprint of the tool. According to embodiments of the present disclosure, tissue ablation comprises iterative and sequential administration of applied voltage at the conductive surfaces, followed by incremental movement 840 of the electrode arrangement, until all targeted tissue is ablated (e.g., FIG. 8C).

[0041] FIG. 9 depicts exemplary tissue ablation operations according to embodiments of the present disclosure. As shown in FIG. 9, the tissue ablation comprises anchoring a PFA tool 910, which can comprise establishing a stable axis of rotation. The axis of rotation can be an axis provided by an anchor that is, for example, anchored in a pulmonary vein. Electrode (e.g.. pairs) can be iteratively activated and repositioned. The positions of electrodes can be mechanically and/or robotically controlled. In some embodiments, the electrode(s) are arranged on an arm that extends (e.g., at an angle 950) from a central axis of the PFA catheter. The arm can be configured to enable good surface contact between the electrode(s) and the target tissue. Good surface contact can comprise sufficient contact to transmit applied electric voltage to the tissue, without overt force being applied to the tissue (e.g., such that the tissue is deformed or damaged). In some embodiments, the electrode arm comprises a device (e.g., spring or motor) configured to provide a target (e.g., range of) applied force 960 to the target tissue upon contact. In some embodiments, the electrode arm comprises one or more sensors that provide feedback regarding a state (e.g., configuration, applied force) of the electrode arm. Sequential administration of applied voltage at the conductive surfaces, followed by incremental movement of the electrode arrangement, can be performed to form an ablation trail 970. The application of ablative energy and movement of the PFA tool 910 can continue until all targeted tissue is ablated.

[0042] In some embodiments, a PFA catheter comprises alternative formulations of electrodes. For example, the electrodes can be deformable. Deformable can include expandable and contractible. The deformable electrodes can be carried on an expansible member (e.g., a balloon, a wireform, or an articulated structure). FIG. 10, for example, depicts an exemplary expandable electrode arrangement 1015 for a PFA catheter 1010. In some embodiments, the electrodes are carried by a balloon 1020. In some embodiments, the expandable electrodes are self-expanding. The array of expandable electrodes can transition from a generally (axially) elongated, radially constrained configuration (not shown) to an axially compressed, radially expanded configuration (e.g., as shown in FIG. 10). In some embodiments, at least one electrode of a plurality of electrodes arranged on the PFA catheter can alter its configuration (e.g., expand) along with the radial expansion of the array. For example, the gaps between series of strips forming the electrode can increase as the array is expanded.

[0043] FIG. 11 depicts an exemplary expandable electrode arrangement 1115 for a PFA catheter 1110. In some embodiments, the electrodes are carried by a balloon 1120. In some embodiments, the expandable electrodes are self-expanding. The array of expandable electrodes can transition from a generally (axially) elongated, radially constrained configuration to an axially compressed, radially expanded configuration (e.g., as shown in FIG. 11).

[0044] FIG. 12 depicts an exemplary expandable electrode arrangement 1215 for a PFA catheter 1210. In some embodiments, the electrodes are carried by a balloon 1220. In some embodiments, the expandable electrodes are self-expanding. The array of expandable electrodes can transition from a generally (axially) elongated, radially constrained configuration to an axially compressed, radially expanded configuration (e.g., as shown in FIG. 12). In some embodiments, at least one electrode of a plurality of electrodes arranged on the PFA catheter can alter its configuration (e.g., expand) along with the radial expansion of the array. For example, the spacings between series of rings forming the electrode can increase as the array is expanded.

[0045] FIG. 13 depicts exemplary expandable electrode array configurations 1320a, 1320b, 1320c, and 1320d formed by wireform and/or wire mesh. Electrodes can be placed at selected positions along the wires and/or mesh to form an expandable electrode array.

[0046] FIGS. 14A-14D depict an exemplary expandable electrode arrangement 1415 for a PFA catheter. Referring to FIGS. 14A-14D together, the PFA catheter can include an elongate guide component 1410. a shaft 1430 positioned around the guide component, a connector positioned around the guide component 1410 and spaced apart from the shaft 1430, an expandable electrode array 1415 coupled between the shaft 1430 and the connector, and a support component 1420 coupled between a distal end of the guide component 1410 and the connector in a coiled arrangement.

[0047] In some embodiments, the guide component 1410 comprises a cable or shaft. The shaft 1430. the connector, and/or the electrode array 1415 can comprise, for example, a hypotube. The hypotube can be composed, at least in part, from Nitinol. The hypotube can be laser-cut to the desired geometry'. In some embodiments, the PFA catheter can be made from materials with high radiodensity' to improve visibility during, for example, x-ray imaging.

[0048] The expandable electrode array 1415 can include a plurality of deformable electrode strips and electrodes disposed thereon. The number of electrodes and/or electrode strips can range, for example, between 4 and 12 or between 6 and 10 (e.g., 8, as shown). In some embodiments, the expandable electrodes are self-expanding. The expandable electrode array 1415 can transition from a generally (axially) elongated, radially constrained configuration (FIG. 14A) (also referred to herein as “the first configuration"’) to an axially compressed, radially expanded configuration (FIG. 14C and 14D) (also referred to herein as “the second configuration”). FIG. 14B shows the array of expandable electrodes 1415 in an intermediate configuration. The guide component 1410 and/or the first shaft 1430 component can be moved relative to one another to switch between the first and second configurations of the PFA catheter. In some embodiments, at least one electrode of a plurality of electrodes arranged on the PFA catheter can alter its configuration (e.g., expand) along with the radial expansion of the array. For example, the gaps between the electrodes can increase as the array is expanded. The deformable nature of the electrode strips can allow for improved placement around and/or contact with the target site or region of interest (ROI).

[0049] In some embodiments, the support component 1420 can have a spiral/helical active function to provide support to the PFA catheter at the target site (e.g., the pulmonary vein’s ostium). As shown in FIGS. 14A-14D, the support component 1420 can be in a radially compressed state when the catheter system is in the first configuration, and in an axially compressed and radially expanded state when the catheter system is in the second configuration.

[0050] In operation, the electrode assembly 1415 can deliver energy to the target site, such as a proximal portion of a pulmonary- vein. When the PFA catheter is in the second configuration, the electrode assembly 1415 can create a circular ablation pattern with an increased electrophoresis application area. In some embodiments, a number of the electrodes (e.g., two, three, four, five, six, seven, eight, nine, ten) can be controlled to apply energy at the target site at a desired direction and/or plane (e.g., anterior-posterior, lateral-medial). Any of the features of the PFA catheters described herein may be combined with any of the features of the other PFA catheters described herein and vice versa.

Examples

[0051] Several aspects of the present technology are set forth in the following examples:

1. An ablation system for treating target tissues in a body, the ablation system comprising: an ablation catheter comprising an elongate shaft having a wall defining a lumen; a guidewire shaft shaped and sized to extend along the ablation catheter within the lumen; an expansible anchor structure coupled to a distal portion of the guidewire shaft, the anchor structure having a collapsed delivery configuration and an expanded anchoring configuration; an ablation member rotatably disposed at a distal end of the elongate shaft and extending axially and laterally therefrom, the ablation member comprising at least two energydelivering electrodes, the ablation member configured for rotation about an axis defined by the distal portion of the guidewire shaft; a pulse generator configured to generate and deliver electrical pulses to the ablation member, and a controller operably coupled to the pulse generator and to the ablation member, the controller adapted to selectively energize the at least two electrodes in a first mode, and to control rotation of the ablation member.

2. The ablation system of example 1 wherein the at least two energy delivery electrodes are further configured, in a second mode, to measure electrical impedance of tissues adjacent thereto.

3. The ablation system of example 2 wherein the controller is configured to repeatably alternate operation of the at least two electrodes from the first mode to the second mode.

4. The ablation system of example 3 wherein the controller is configured to maintain a duration of tissue contact in the first mode considering the electrical impedance measured at the tissues while in the second mode.

5. The ablation system of example 4 wherein the controller is configured to rotate the ablation member to a new tissue location at a step size considering at least one of (a) the duration of tissue contact, (b) the voltage level of delivered electrical pulses, (c) the electrical impedance measurement, and (d) stored positions that correspond to locations of prior tissue ablations.

6. The ablation system of any one of examples 1-5 wherein the controller is configured to rotate the ablation member to a new tissue location at a predetermined step size considering at least one of (a) a previous commanded position of the ablation member and (b) the voltage level of delivered electrical pulses.

7. The ablation system of any one of examples 1-6 wherein, upon rotation of the ablation member from a first tissue contact position to a second tissue contact position, the controller is further configured to position the ablation member such that at least one of the at least two energy' delivering electrodes contacts a same portion of treated tissue in the first and second tissue contact positions. 8. The ablation system of any one of examples 1-7, further comprising a force sensor operably coupled with the ablation member and the controller, wherein the force sensor is configured to provide a signal indicating a tissue contact force of the ablation member.

9. The ablation system of example 8 wherein the controller is further configured to adjust an angle and/or a position of the ablation member to alter the tissue contact force toward a target value thereof.

10. The ablation system of any one of examples 1-9 wherein anchor structure is an expandable balloon.

11. The ablation system of any one of examples 1-9 wherein anchor structure is a braid structure.

12. A method of ablating target tissues in a body, the method comprising: advancing a guidewire shaft comprising an anchoring structure toward an ostia of a pulmonary⁷ vein; deploying the anchoring structure within the ostia to anchor the guidewire; advancing an ablation catheter carrying an extended ablation arm having a pair of electrodes over the guidewire; contacting, with the pair of electrodes, target tissue at a first position; delivering energy in a first pulse to the pair of electrodes; rotating the ablation arm to a next position adjacent to the prior position; and delivering energy' in a subsequent pulse to the pair of electrodes.

13. The method of example 12 wherein the target tissue is adjacent an ostia, further comprising repeating rotation of the ablation arm and delivery of energy until a perimeter of tissue adjacent the ostia has received ablative energy'.

14. The method of example 12 or example 13, further comprising measuring at least one of a tissue temperature and a tissue impedance during and/or following the delivering energy. 15. The method of example 14 wherein determining at least one of the next position and the energy of the subsequent pulse is made considering the measured tissue temperature and/or impedance.

16. The method of example 14 wherein measuring the impedance comprises measuring impedance spectra.

17. The method of any one of examples 14-16 wherein measuring the tissue temperature and/or the tissue impedance is performed by the pair of electrodes.

18. The method of any one of examples 14-17 wherein measuring the tissue temperature and/or the tissue impedance is performed by a second pair of electrodes having electrodes adjacent the first pair of electrodes.

19. The method of any one of examples 12-18, further comprising maintaining a selected tissue contact force during contacting tissue.

20. An ablation catheter for treating target tissues in a body, the ablation catheter comprising: an elongate shaft having a wall defining a lumen; a region of conductive surfaces disposed along a distal portion of the elongate shaft and configured to contact target tissue; a guidewire shaft disposed within the lumen and extending along the elongate shaft; and at least two electrodes movably disposed within the lumen and configured for electrical coupling to the region of conductive surfaces, wherein each electrode is independently movable along the guidewire shaft to interface with a selected portion of the region of conductive surfaces to delivery energy therethrough.

21. The ablation catheter of example 20 wherein each electrode of the at least two electrodes comprises: an electrode lumen sized for passing the guidewire shaft therethrough, and an electrode wire extending proximally therefrom and configured for coupling to a pulse generator source. 22. The ablation catheter of example 21, further comprising a robotic controller operably coupled with the electrode wires, the robotic controller configured to move and to energize electrodes of the at least two electrodes.

23. The ablation catheter of example 21 or example 22 wherein the electrode wire of is further configured to move its corresponding electrode of the at least two electrodes along the guidewire shaft.

24. The ablation catheter of any one of examples 20-23 wherein movement of at least two electrodes is constrained to prevent direct tissue contact therewith.

25. The ablation catheter of any one of examples 20-24 wherein the region of conductive surfaces is free of any fixed electrical connections.

26. The ablation catheter of example 25 wherein the region of conductive surfaces comprises a plurality of contact pads.

27. The ablation catheter of example 26 wherein each contact pad of the plurality of contact pads is spaced at a regular interval along the distal portion of the elongate shaft.

28. The ablation catheter of any one of examples 20-27 wherein the region of conductive surfaces comprises porosities that penetrate from an interior to an exterior of the wall.

29. The ablation catheter of example 28 wherein the porosities are configured to pass a conductive fluid from the interior to the exterior of the wall.

30. The ablation catheter of example 29 wherein the conductive fluid has a higher conductivity than blood or the target tissue.

31. The ablation catheter of any one of examples 20-30 wherein the distal portion of the elongate shaft is configurable between a generally straightened configuration and a curved configuration. 32. The ablation catheter of any one of examples 20-31, further comprising an expansible anchor structure coupled to a distal portion of the guide wire shaft, the anchor structure having a collapsed delivery configuration and an expanded anchoring configuration for anchoring to tissue.

33. The ablation catheter of example 32 wherein the expansible anchor structure comprises an anchor electrode.

34. A catheter system for delivering ablative energy to target tissue of a patient, the catheter comprising: an elongate guide component; a shaft positioned around and extending along the elongate guide component; a connector positioned around the elongate guide component and spaced apart from the shaft; a plurality of electrode strips coupled between the shaft and the connector, wherein the electrode strips are arranged radially around the elongate guide component, and wherein the electrode strips are deformable, wherein the catheter system is movable between — a first configuration in which the plurality of electrode strips extend linearly along the elongate guide component and are radially compressed, while the shaft and the connector are spaced apart by a first distance, and a second configuration in which the plurality electrode strips are axially compressed and radially expanded, while the shaft and the connector are spaced apart by a second distance that is smaller than the first distance.

35. The catheter system of example 34 wherein the catheter system further comprises an expansible structure that carries the plurality of electrode strips.

36. The catheter system of example 35 wherein the plurality of electrode strips comprise an electrode array, and further wherein expansion of the expansible structure further causes expansion of at least one electrode in the electrode array. Conclusion

[0052] The above detailed description of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Although specific embodiments of. and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology as those skilled in the relevant art will recognize. For example, any of the features of the PF A catheters described herein may be combined with any of the features of the other PFA catheters described herein and vice versa. Moreover, although steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.

[0053] From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. To the extent any material incorporated herein by reference conflicts with the present disclosure, the present disclosure controls.

[0054] Where the context permits, singular or plural terms may also include the plural or singular term, respectively. In addition, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Furthermore, as used herein, the phrase “and/or” as in “A and/or B” refers to A alone, B alone, and both A and B. Additionally, the terms “comprising,” “including,” “having,” and “with” are used throughout to mean including at least the recited feature(s) such that any greater number of the same features and/or additional types of other features are not precluded. Moreover, as used herein, the phrases “based on,” “depends on.” “as a result of.” and “in response to” shall not be construed as a reference to a closed set of conditions. For example, an exemplar}' step that is described as “based on condition A” may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on” or the phrase “based at least partially on.”

[0055] From the foregoing, it will also be appreciated that various modifications may be made without deviating from the disclosure or the technology. For example, one of ordinary skill in the art will understand that various components of the technology can be further divided into subcomponents, or that various components and functions of the technology may be combined and integrated. In addition, certain aspects of the technology described in the context of particular embodiments may also be combined or eliminated in other embodiments. Furthermore, although advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

Claims

CLAIMS I/'W e claim:

1. An ablation system for treating target tissues in a body, the ablation system comprising: an ablation catheter comprising an elongate shaft having a wall defining a lumen; a guidewire shaft shaped and sized to extend along the ablation catheter within the lumen; an expansible anchor structure coupled to a distal portion of the guidewire shaft, the anchor structure having a collapsed delivery configuration and an expanded anchoring configuration; an ablation member rotatably disposed at a distal end of the elongate shaft and extending axially and laterally therefrom, the ablation member comprising at least two energy delivering electrodes, the ablation member configured for rotation about an axis defined by the distal portion of the guidewire shaft; a pulse generator configured to generate and deliver electrical pulses to the ablation member, and a controller operably coupled to the pulse generator and to the ablation member, the controller adapted to selectively energize the at least two electrodes in a first mode, and to control rotation of the ablation member.

2. The ablation system of claim 1 wherein the at least two energy’ delivery electrodes are further configured, in a second mode, to measure electrical impedance of tissues adjacent thereto.

3. The ablation system of claim 2 wherein the controller is configured to repeatably alternate operation of the at least two electrodes from the first mode to the second mode.

4. The ablation system of claim 3 wherein the controller is configured to maintain a duration of tissue contact in the first mode considering the electrical impedance measured at the tissues while in the second mode.

5. The ablation system of claim 4 wherein the controller is configured to rotate the ablation member to a new tissue location at a step size considering at least one of (a) the duration of tissue contact, (b) the voltage level of delivered electrical pulses, (c) the electrical impedance measurement, and (d) stored positions that correspond to locations of prior tissue ablations.

6. The ablation system of claim 1 wherein the controller is configured to rotate the ablation member to a new tissue location at a predetermined step size considering at least one of (a) a previous commanded position of the ablation member and (b) the voltage level of delivered electrical pulses.

7. The ablation system of claim 1 wherein, upon rotation of the ablation member from a first tissue contact position to a second tissue contact position, the controller is further configured to position the ablation member such that at least one of the at least two energy delivering electrodes contacts a same portion of treated tissue in the first and second tissue contact positions.

8. The ablation system of claim 1 , further comprising a force sensor operably coupled with the ablation member and the controller, wherein the force sensor is configured to provide a signal indicating a tissue contact force of the ablation member.

9. The ablation system of claim 8 wherein the controller is further configured to adjust an angle and/or a position of the ablation member to alter the tissue contact force toward a target value thereof.

10. The ablation system of claim 1 wherein anchor structure is an expandable balloon.

11. The ablation system of claim 1 wherein anchor structure is a braid structure.

12. A method of ablating target tissues in a body, the method comprising: advancing a guidewire shaft comprising an anchoring structure toward an ostia of a pulmonary vein; deploying the anchoring structure within the ostia to anchor the guidewire; advancing an ablation catheter carrying an extended ablation arm having a pair of electrodes over the guidewire; contacting, with the pair of electrodes, target tissue at a first position; delivering energy- in a first pulse to the pair of electrodes; rotating the ablation arm to a next position adjacent to the prior position; and delivering energy- in a subsequent pulse to the pair of electrodes.

13. The method of claim 12 wherein the target tissue is adjacent an ostia, further comprising repeating rotation of the ablation arm and delivery of energy until a perimeter of tissue adjacent the ostia has received ablative energy-.

14. The method of claim 12, further comprising measuring at least one of a tissue temperature and a tissue impedance during and/or following the delivering energy.

15. The method of claim 14 wherein determining at least one of the next position and the energy of the subsequent pulse is made considering the measured tissue temperature and/or impedance.

16. The method of claim 14 wherein measuring the impedance comprises measuring impedance spectra.

17. The method of claim 14 wherein measuring the tissue temperature and/or the tissue impedance is performed by the pair of electrodes.

18. The method of claim 14 wherein measuring the tissue temperature and/or the tissue impedance is performed by a second pair of electrodes having electrodes adjacent the first pair of electrodes.

19. The method of claim 12, further comprising maintaining a selected tissue contact force during contacting tissue.

20. An ablation catheter for treating target tissues in a body, the ablation catheter comprising: an elongate shaft having a wall defining a lumen; a region of conductive surfaces disposed along a distal portion of the elongate shaft and configured to contact target tissue; a guidewire shaft disposed within the lumen and extending along the elongate shaft: and at least two electrodes movably disposed within the lumen and configured for electrical coupling to the region of conductive surfaces, wherein each electrode is independently movable along the guidewire shaft to interface with a selected portion of the region of conductive surfaces to delivery energy therethrough.

21. The ablation catheter of claim 20 wherein each electrode of the at least two electrodes comprises: an electrode lumen sized for passing the guidewire shaft therethrough, and an electrode wire extending proximally therefrom and configured for coupling to a pulse generator source.

22. The ablation catheter of claim 21, further comprising a robotic controller operably coupled with the electrode wires, the robotic controller configured to move and to energize electrodes of the at least two electrodes.

23. The ablation catheter of claim 21 wherein the electrode wire of is further configured to move its corresponding electrode of the at least two electrodes along the guidewire shaft.

24. The ablation catheter of claim 20 wherein movement of at least two electrodes is constrained to prevent direct tissue contact therewith.

25. The ablation catheter of claim 20 wherein the region of conductive surfaces is free of any fixed electrical connections.

26. The ablation catheter of claim 25 wherein the region of conductive surfaces comprises a plurality of contact pads.

27. The ablation catheter of claim 26 wherein each contact pad of the plurality of contact pads is spaced at a regular interval along the distal portion of the elongate shaft.

28. The ablation catheter of claim 20 wherein the region of conductive surfaces comprises porosities that penetrate from an interior to an exterior of the wall.

29. The ablation catheter of claim 28 wherein the porosities are configured to pass a conductive fluid from the interior to the exterior of the wall.

30. The ablation catheter of claim 29 wherein the conductive fluid has a higher conductivity than blood or the target tissue.

31. The ablation catheter of claim 20 wherein the distal portion of the elongate shaft is configurable between a generally straightened configuration and a curved configuration.

32. The ablation catheter of claim 20, further comprising an expansible anchor structure coupled to a distal portion of the guidewire shaft, the anchor structure having a collapsed delivery configuration and an expanded anchoring configuration for anchoring to tissue.

33. The ablation catheter of claim 32 wherein the expansible anchor structure comprises an anchor electrode.

35. The catheter system of claim 34 wherein the catheter system further comprises an expansible structure that carries the plurality’ of electrode strips.

36. The catheter system of claim 35 wherein the plurality of electrode strips comprise an electrode array, and further wherein expansion of the expansible structure further causes expansion of at least one electrode in the electrode array.