Pulsed field ablation device and method

Abstract

To provide an ablation device and method for pulsed field ablation.SOLUTION: The device comprises a catheter including an expandable basket, a set of electrodes 109 formed on the expandable basket, and a pulse generator suitable for generating electric pulses where the pulse generator is in electrical connection with a pair of electrodes. The expandable basket is formed of a braided mesh 413 of filaments, where the filaments are made of nonconductive material, where at least portion of the filaments comprises a lumen, where the filaments further include electrodes and conductive wires 417. The conductive wires at least partially lead to inside of the lumen of the filaments and are electrically connected to the electrodes.SELECTED DRAWING: Figure 10

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Nos. 63 / 171,832, filed April 7, 2021, 63 / 218,563, filed July 6, 2021, and 63 / 249,965, filed September 29, 2021, all of which are incorporated by reference herein in their entireties. [Technical Field]

[0002] The present invention relates to ablation devices and methods, and in particular to devices and methods for pulsed field ablation of target tissue by pulsed electric fields, where one of the main principles of ablation can be irreversible electroporation of cell membranes. [Background technology]

[0003] Atrial fibrillation is the most common sustained cardiac arrhythmia, affecting 10% of the population over the age of 60. In addition to pharmacological treatment, an established treatment to improve the symptoms of the disease and reduce mortality is the so-called catheter ablation.

[0004] Catheter ablation typically involves subcutaneously advancing one or more flexible catheters into a patient's blood vessels, either in the femoral, internal jugular, or subclavian vein, for cardiac ablation, and then advancing the catheters toward a target treatment site within or on the surface of the heart.

[0005] The primary ablation approach to cardiac arrhythmia treatment involves either directly eliminating the arrhythmogenic substrate by disrupting it or preventing nonphysiological action potential propagation by linear or circular isolation. Both of these approaches require the creation of a lesion that essentially blocks myocardial action potential propagation. By applying energy, small portions of myocardium are locally destroyed and converted into nonmyocardial connective tissue by natural physiological processes within a few weeks.

[0006] Common ablation methods known from the prior art are based on the thermal destruction of tissue by either high or low temperatures. Such methods include, for example, heating the target tissue by a radio frequency field (RF) or a laser, or freezing the tissue by cryoablation. These methods cause necrosis of the target tissue, which can add risks to the procedure.

[0007] Recently, methods and devices using electric fields for ablation have been utilized. The purpose of these methods is to induce irreversible electroporation of cell membranes to cause tissue destruction instead of destruction by high or low temperatures, thereby reducing the drawbacks and risks of ablation procedures that are primarily based on thermal damage. However, there are still drawbacks that need to be resolved.

[0008] A common design for such devices is a catheter with a distal tip containing one or more electrodes. The catheter may have, for example, a single active electrode at the tip. An unrelated electrode may be placed on the patient's skin, for example. Ablation of the target treatment site using such a device must be performed point-by-point, which increases the duration and complexity of the procedure.

[0009] Another example of a conventional device is a catheter with a row of electrodes at the distal tip of a single catheter body. A catheter with a flexed distal tip is delivered near the target treatment site and deployed (bent) into a specific shape near the target treatment site. While this configuration allows for the use of two or more electrodes for treatment and requires less distal tip movement, deploying the catheter into the correct shape and properly positioning and maneuvering such a catheter can be very challenging. Similarly, unrelated electrodes can be placed on the patient's skin, or ablation can be performed in a bipolar fashion between specific electrodes located at the distal end of the catheter.

[0010] Devices with catheter terminal baskets containing a single strut carrying an electrode are also known in the prior art. Such devices can ensure easier deployment and positioning relative to the target site. Because more electrodes are typically located on the catheter terminal, ablation can again be either monopolar, with an unrelated electrode placed on the patient's skin, for example, or bipolar between specific electrodes on the catheter terminal. One drawback of this solution is the limited number of struts, which means that a limited number of electrodes create a specific circular pattern in space. This drawback stems from the need for mechanical stability of specific struts to ensure the basket maintains a stable shape. This means that the struts must be sufficiently rigid and maintain specific dimensions. The number of struts used is then limited by the size of the catheter. Another drawback of this solution is that such a structure cannot fully guarantee the mutual distance of the struts in the deployed configuration, which means that the distance between the electrodes cannot be guaranteed. This means that the device may need to be repositioned multiple times to ensure proper ablation, which extends the duration of the procedure.

[0011] There is a need to increase the quality and safety of ablation while reducing patient risk and treatment duration. Thus, there is a need for improved ablation devices and methods that are gentler and safer for the patient, with reduced complexity and improved quality and reliability of the methods and devices themselves. Summary of the Invention

[0012] Disclosed herein are ablation system devices and methods, in particular ablation methods and devices for pulsed field ablation with electric fields according to the description, which can address and solve the above-mentioned problems, are gentler and safer for the patient, require less time and technical complexity, and improve the quality, effectiveness and reliability of the systems, methods and devices themselves. [Brief explanation of the drawings]

[0013] Exemplary aspects of the present disclosure are illustrated by way of example in the accompanying drawings, in which like reference numerals indicate the same or similar elements.

[0014] [Figure 1] FIG. 1 is a block diagram of an exemplary ablation system.

[0015] [Figure 2] 1 is a schematic of an exemplary pulsed field ablation device with a catheter.

[0016] [Figure 3A] 1 illustrates an exemplary catheter having a shaft assembly.

[0017] [Figure 3B] 1 is an exemplary cross-sectional view of a shaft assembly.

[0018] [Figure 4] 1 is an exemplary representation of a distal tip of a catheter having a basket assembly in an expanded configuration.

[0019] [Figure 5] 1 illustrates an exemplary distal tip of a catheter having a basket assembly in a collapsed configuration.

[0020] [Figure 6A] 1 illustrates an exemplary expandable basket.

[0021] [Figure 6B] FIG. 10 is a detailed view of an exemplary expandable basket with filaments.

[0022] [Figure 6C] FIG. 10 is a detailed view of an exemplary expandable basket with filaments and conductive wires.

[0023] [Figure 7A] FIG. 1 is a front view of an exemplary distal tip of a catheter.

[0024] [Figure 7B] FIG. 1 is a side view of an exemplary distal tip of a catheter.

[0025] [Figure 8] 1 illustrates an exemplary braided mesh with elongated electrodes.

[0026] [Figure 9] 1 shows an exemplary braided mesh having filaments and conductive wires inside the lumens of the filaments.

[0027] [Figure 10] 10A-10C are exemplary schematic diagrams of the position of the basket assembly adjacent to the treatment site.

[0028] [Figure 11] 1 is a schematic diagram of an exemplary mode of operation of an electrode.

[0029] [Figure 12] 10 is a schematic diagram of another exemplary mode of operation of the electrodes. FIG.

[0030] [Figure 13A] 1 is an example of a spatial pattern of electrodes at the distal tip of a catheter.

[0031] [Figure 13B] 1 is another example of a spatial pattern of electrodes at the distal tip of a catheter.

[0032] [Figure 14] 10 is a diagram of a possible layout of electrodes already switched to a hybrid mode of operation. FIG.

[0033] [Figure 15A] 1 shows an exemplary pattern of electrodes.

[0034] [Figure 15B] 10 shows another exemplary pattern of electrodes.

[0035] [Figure 15C] 10 shows another exemplary pattern of electrodes.

[0036] [Figure 16] 1 illustrates a portion of an exemplary pulsed field ablation protocol.

[0037] [Figure 17a] Examples of inter-pulse pauses with voltages different from 0V are shown.

[0038] [Figure 17b] 1 shows examples of different biphasic pulses.

[0039] [Figure 18] FIG. 1 illustrates an example of a terminal assembly.

[0040] [Figure 19] 1 illustrates another view of an exemplary terminal assembly.

[0041] [Figure 20] 1 shows an example of filaments joined to each other at their intersections.

[0042] [Figure 21] FIG. 10 is a view of the distal portion of a basket assembly having a merging structure and a living hinge. DETAILED DESCRIPTION OF THE INVENTION

[0043] FIG. 1 illustrates an ablation system (100) for pulsed field ablation of target tissue. The ablation system (100) described herein includes a pulsed field ablation device (101). The ablation system (100) may include or be connected to other parts or devices suitable for performing or supporting the pulsed field ablation methods described herein. The other parts or devices may be, for example, a control unit (111), a graphical user interface (GUI) unit (113), an electrical control circuit (115), an electrocardiogram (ECG) trigger circuit (117), an ECG recording device (129), ECG electrodes (125), a pacing device (131), a catheter signal interconnect circuit (119), and / or an electrophysiology (EP) display device (133), which may include an EP recording system. The EP display device may display and / or record data from one or more other devices connected to the ablation system (100). Additionally, the ablation system (100) can include a mapping device (135), such as a three-dimensional (3D) mapping device or a real-time position measurement (RPM) device, and / or an unrelated electrode (127). The mapping device (135) records, for example, EGMs (intracardiac electrograms) of locations in space measured by the catheter, creating a map of the heart's surface. This can also indicate the position and orientation of the catheter. Other possible methods for measuring the actual position of the catheter can be via sensors in the catheter (e.g., magnetic-based localization), or using, for example, impedance measurements at the catheter's electrodes, or measurements based on radio frequency or a combination thereof. Advantageously, in some instances, the catheter used for localization is the same catheter used for ablation.

[0044] The pulsed field ablation device (101) includes a pulse generator (103) for generating short, high-voltage electrical pulses, and a catheter (105) suitable for insertion into a body cavity of a patient, the catheter having a distal tip (107) suitable for performing pulsed field ablation of target tissue with a pulsed electric field using a set of electrodes (109). The catheter (105) is in electrical communication with the pulse generator (103).

[0045] The pulsed field ablation device (101) may include or be connected to other parts or devices suitable for performing or supporting the pulsed field ablation methods described herein. The other parts or devices may be, for example, a remote control unit (111), a graphical user interface (GUI) unit (113), an electrocardiogram (ECG) device including an electrical control circuit (115), an ECG trigger circuit (117), an ECG recording device (129), ECG electrodes (125), a pacing device (131), a catheter signal interconnect circuit (119), and / or an electrophysiology (EP) display device (133), which may include an EP recording system. The EP display device may display and / or record data from other devices connected to the ablation system (100). Additionally, the ablation system (100) may include a mapping device (135), such as a three-dimensional (3D) mapping device or a real-time position measurement (RPM) device, and / or an extraneous electrode (127). For example, the pulsed field ablation device (101) can be configured for use within or on a patient's heart, e.g., for the treatment of cardiac tissue, e.g., for pulsed field ablation of cardiac tissue, e.g., for pulsed field ablation of myocardial tissue, e.g., for pulmonary vein isolation. The devices and methods disclosed herein can be used elsewhere, e.g., in any tubular tissue, organ, or vessel within the body, or at the site of, e.g., a tumor.

[0046] The catheter (105) shown in Figure 2 includes a shaft assembly (201) and a catheter distal tip (107) disposed adjacent to the distal portion of the catheter (105). The shaft assembly (201) defines a central longitudinal axis (203) of the catheter (105). The catheter (105) may further include a handle assembly (123) and a connecting assembly (121). The catheter (105) may be steerable or non-steerable and may be introduced into position, for example, via an introducer sheath (not shown), with or without the aid of a guidewire (not shown).

[0047] The connection assembly (121) of the catheter (105) can serve to interconnect the catheter (105) with other portions of the ablation system (100). The connection assembly (121) can include a single connection portion or more spatially separated connection portions. The connection assembly (121) can be located in a proximal portion of the catheter (105) and / or can be part of, for example, the handle assembly (123). The connection assembly (121) portion can include, for example, one or more electrical connections, mechanical connections, fluid connections, and / or inputs for guidewires.

[0048] The handle assembly (123) may be attached to the catheter shaft assembly (201) and may function, for example, to steer and manipulate the catheter (105) and / or precisely control the movement and deflection of the catheter (105). To enable steering functions, there may be a knob (not shown) attached adjacent to the distal section of the catheter (105) that is fed through a separate lumen and connected to steering wires (not shown), which may be connected to a knob or steering mechanism (not shown) inside the handle assembly (123). The handle assembly (123) may further include a grip (not shown) and / or a deployment mechanism (not shown) that deploys / retracts the distal tip basket assembly (401, see FIG. 4 ) and / or the expandable basket (409) by pushing / pulling the connection assembly (121) or one or more connecting portions of the connection assembly (121) and other portions, such as the inner elongate shaft (301) and / or outer elongate shaft (303) relative to one another. The deployment mechanism can include, for example, an actuator for longitudinally actuating the inner elongate shaft (301) relative to the outer elongate shaft (303).

[0049] FIG. 3A shows a catheter (105) having a shaft assembly (201). The shaft assembly may include an outer elongate shaft (303) and / or an inner elongate shaft (301). A cross section of the exemplary shaft assembly (201) at section AA shown in FIG. 3B may include two concentric tubes, the outer tube being the outer elongate shaft (303) and the inner tube being the inner elongate shaft (301). The shafts can translate longitudinally relative to one another along the central longitudinal axis (203). This translation may, for example, allow the expandable basket (409) to be deployed / retracted from a collapsed configuration to a fully expanded configuration and back again.

[0050] The outer elongate shaft can include a proximal portion, a distal portion, and a body extending between the proximal and distal ends. The outer elongate shaft can be coupled to a handle assembly adjacent its proximal portion and to a catheter distal tip adjacent its distal portion.

[0051] The body of the outer elongate shaft (303) can include one or more lumens (309, 311), e.g., extending along its entire length between the proximal and distal ends. The lumens can accommodate, for example, lead wires or fluids, e.g., irrigation fluid. One or more of the lumens can be configured to receive one or more of the inner elongate shafts. The body of the outer elongate shaft can be, for example, defined by a proximal section (305) and a central section (307). The central section of the body can be further defined with a more flexible jacket than the proximal section, allowing for bending of the outer elongate shaft and increasing flexibility. The proximal section includes a more rigid material jacket, for example, to increase torque and stiffness of the outer elongate shaft body. Suitable materials for construction of the jacket include, but are not limited to, nylon, TPU, HDPE, or PEBA.

[0052] The body of the outer elongate shaft can include conductive wires. The conductive wires can pass through a central lumen (309) of the outer elongate shaft, or the outer elongate shaft can include several other lumens (311), such that one or more of the wires can pass through one or more of the other lumens (311). For example, the number of other lumens can correspond to the number of filaments in the braided mesh of the catheter distal tip; for example, if 20 filaments are used to construct the catheter distal tip, 20 other lumens can be used.

[0053] The conductive wires may extend from the basket assembly to a connection assembly, for example, adjacent the handle assembly.

[0054] In some embodiments, the inner elongate shaft can be configured to slide relative to the outer elongate shaft along the central longitudinal axis. Accordingly, one or more of the lumens can include, for example, a low-friction liner, such as a polytetrafluoroethylene (PTFE) liner.

[0055] Stiffness and torque are important characteristics for the outer elongate shaft to possess, and therefore the outer elongate shaft can comprise a braid of metal or rigid polymer wire wrapped around the inner layer of the body, for example, laterally over / around a PTFE liner, and in some embodiments embedded within the outer jacket of the body, or can comprise a rigid polymer, including but not limited to, polyimide, polyamide, polyetheretherketone (PEEK), or any other suitable material.

[0056] The outer layer of the outer elongate shaft may comprise a laminated polymer to provide a seamless, smooth, and soft surface. As previously mentioned, the outermost layers of the central and proximal sections may be formed from different polymers; for example, a nylon material may be used for the proximal section, while a PEBA, which is more flexible than nylon, may be used for the outermost layer of the central section. However, both sections may have the same innermost layer. The outer elongate shaft may have a substantially constant outer diameter along its length.

[0057] The outer diameter (OD) dimension of the outer elongate shaft can conform, for example, to the French catheter scale, which is commonly used to standardize catheter sizes. Diameters on this scale are defined in French (FR), where 1 mm = 3 FR. The scale typically ranges from 3 FR catheters to 34 FR catheters. For example, the diameter of the outer elongate shaft can be between 5 FR and 20 FR, or between 7 FR and 16 FR, or between 9 FR and 15 FR. The diameter of the central lumen of the outer elongate shaft can be approximately 0.1 mm to 5 mm, or between 1 mm and 4 mm, or between 2 mm and 3.5 mm, or between 2.5 mm and 3 mm.

[0058] The inner elongate shaft can include a proximal end, a distal end, and a body extending between the proximal and distal ends. The body of the inner elongate shaft can include one or more lumens (313), for example, extending along the entire length of the inner elongate shaft between the proximal and distal ends, or can be lumenless. The one or more lumens (313) of the inner elongate shaft can be designed, for example, to accommodate a standard guidewire (not shown) and / or to conduct fluid, for example, irrigation fluid. The diameter of the one or more lumens (313) can range from 0.1 mm to 3 mm, or The diameter of the inner elongate shaft (309, 311) may be 0.5 mm to 1.5 mm, or 0.9 mm to 1 mm, or 0.94 mm to 0.99 mm. One or more of the inner elongate shafts may be adapted for placement in one or more lumens (309, 311) of the outer elongate shaft. The dimensions of the inner elongate shaft may be selected to match the diameter of the designated lumen of the outer elongate shaft, yet the two structures must still allow for smooth relative movement between them. That is, the outer dimensions of the inner elongate shaft (301) may be 0.1 mm to 4.9 mm, or 0.5 mm to 3.5 mm, or 1 mm to 3 mm, or 1.28 mm to 2.8 mm.

[0059] The inner elongate shaft may be adapted to accommodate a guidewire within its lumen, so that a low friction liner of the inner lumen, such as a PTFE liner, may be used.

[0060] As mentioned above, the inner elongate shaft can translate relative to the outer elongate shaft to deploy the basket assembly / expandable basket, and thus, for example, a braided socket can be woven along the length of the PTFE liner to form the body of the inner elongate shaft. Another embodiment can include a cut hypotube in place of the braid in the body of the inner elongate shaft to improve its flexibility and torque.

[0061] A polymer jacket can be melt / laminated laterally over the layer with the braid or hypotube to increase the flexibility of the tube and provide a seamless surface. A variety of polymers can be used for the jacket; exemplary materials can be NYLON, polyether block amide (PEBA), polyether ether ketone (PEEK), or polyimide.

[0062] The distal tip portion (107) of the example catheter shown in Figure 4 further includes a basket assembly (401). The basket assembly (401) can include a basket assembly proximal portion (403), a basket assembly distal portion (405), and a basket assembly body (407) extending between the proximal and distal portions. The basket assembly body can include a central body portion (419) that occupies approximately one-third of the basket assembly body and extends about a plane (425) that intersects the basket assembly at a portion having a largest diameter in the proximal and distal directions (in one of its expanded configurations). The basket assembly body can further include a distal body portion (421) extending distally from the central body portion (419) and a proximal body portion (423) extending proximally from the central body portion (419), each of which occupies approximately one-third of the basket assembly body (407).

[0063] The basket assembly (401) includes an expandable basket (409). The basket assembly proximal portion (403) can include attachment of the proximal portion of the expandable basket (409) adjacent to the distal end of the outer elongate shaft (303). The distal portion of the basket assembly (401) can include attachment of the distal portion of the expandable basket (409) adjacent to the distal end of one or more of the inner elongate shafts (301) that form the contact assembly (411).

[0064] The terminal assembly (411) can be advantageously designed without, or at least with a reduced structure, such as a cap or similar formation, protruding distally from the basket assembly distal portion (405), which is particularly advantageous in situations where at least part of the ablation procedure needs to be performed in a relatively flat treatment site.

[0065] An exemplary solution for the terminal assembly may be an overmolded structure, in which the filaments are bonded to each other and / or to the distal end of the inner elongate shaft by an overmolding process. The filaments can be secured to a terminal assembly to form an overmolded terminal assembly. Another securing procedure (and / or terminal assembly fabrication procedure) similar to overmolding can be, for example, tilting, in which the filaments are at least partially melted and forced into a pre-shaped mold, thus connecting them to each other and / or the inner elongated shaft. Lamination is another exemplary process for securing filaments to their distal ends to form a terminal assembly. Terminal assemblies can also be fabricated by swaging or crimping the distal ends of the filaments. The filaments can be brought together in the terminal assembly area and swaged or crimped together, for example, by some type of metal ring.

[0066] In another example, the terminal assembly may be fabricated as a hinged mechanical structure, as shown in FIG. 18 . For example, one or more filaments may be at their distal ends in a region of the terminal assembly secured to an articulation element (1801), which may include, for example, a lateral narrow portion (1803) and a distal portion (1805) that is wider than the lateral narrow portion (1803). The lateral narrow portion (1803) may be in the form of a pin having, for example, a square, rectangular, circular, elliptical, or other suitable cross-section. The distal portion (1805) may have, for example, an elliptical or circular shape, or in another example, a ball or sphere shape. Other possible shapes of the distal portion (1805) may be cylindrical, conical, cubical, or block-shaped. This can have one of the same dimensions as the lateral narrow portion (1803), for example, if the entire articulating element (1801) is made from a single piece of sheet material (metal sheet, polymer sheet), or if not (for example, if the articulating element is cast or forged). The articulating element (1801) can be made, for example, from a metal (e.g., nitinol) or other material, such as a polymer or thermoplastic. The filament can be secured to the articulating element by, for example, welding, gluing, or crimping. The connection area (1807) can be at least partially laminated, for example, to prevent possible tissue damage and seal the assembly. The articulating element is then secured within a central projectile structure (1809). This can be, for example, a hollow structure with a cutting window (1811) suitable for receiving the proximal portion (1803) of the articulating element (1801). In this case, the distal portion (1805) of the articulating element is positioned within the inner cavity (1813) of the hollow structure. The distal portion (1805) of the articulation element may, in some instances, have a dimension (cross-section or width) that is greater than the dimension of the window (1811), thereby preventing slippage of the distal portion (1805) of the articulation element (1801) through the window (1811), thus retaining the articulation element, and with it the distal portion of the filament attached to the connection region (1807) and central bullet structure (1809).The central bullet structure (1809) can include several sections connected to each other (e.g., by welding, gluing, or other mechanical means such as snaps, threading, screws, bolts, etc.). It can also have different external shapes, e.g., cylindrical, spherical, or elliptical. The shape of the cavity (1813) can correspond to the external shape or can be different. The central bullet structure can include a fixing portion (1815) for fixing the distal end of the inner elongate shaft to the central bullet structure. The fixing portion (1815) can have, for example, the shape of a hollow tube connected to the central bullet structure. The fixing portion is suitable for receiving and / or connecting the distal portion of the inner elongate shaft and can allow the flow and / or redirection of fluids, e.g., irrigation fluids, emerging from the lumen of the inner elongate shaft. The fixing portion can interface with the cavity (1813) or can be mechanically and / or fluidically connected thereto. This may be adapted to direct at least a portion of the irrigation fluid into the cavity of the central projectile structure, for example by means of an opening (1901) as shown in FIG.

[0067] Such hinge mechanical structures as described above can allow for easier radial movement (relative to the central longitudinal axis of the catheter) of the filament in the region of the terminal assembly, which can be advantageous during operation with the expandable basket, particularly in the transition (deployment / retraction) between a collapsed configuration and one or more expanded configurations.

[0068] When metal components are used in the design of the terminal assembly, they can be used as electrodes, for example, for ablation or sensing or mapping or a combination thereof.

[0069] The expandable basket may be attached to the inner and / or outer elongate shafts, for example, by gluing, welding, laminating, or by mechanical means.

[0070] The expandable basket (409) is configured for transition (deployment / retraction) between a collapsed configuration, for example, as shown in FIG. 5, and one or more expanded configurations. The transition (deployment / retraction) may be caused by the shape of the pretensioned braided mesh (413) and / or filaments (415), and / or by linear displacement of the inner elongate shaft (301) relative to the outer elongate shaft (303) along the central longitudinal axis (203) of the catheter (105), or a combination thereof. Another possibility for deployment / retraction of the expandable basket (409) may be by the tension of an additional support structure, such as an inner coil or balloon (not shown).

[0071] The expandable basket includes filaments woven into a mesh. In the collapsed configuration, the cross-section of the expandable basket can be equal to or close in size to the cross-section of the outer elongate shaft, although in some embodiments, the cross-section of the expandable basket can be smaller than the cross-section of the outer elongate shaft, depending on the dimensions of the outer elongate shaft. In the expanded configuration, the cross-section of the expandable basket can be significantly larger than the cross-section of the outer elongate shaft. The fully expanded expandable basket can have a maximum cross-sectional diameter of, for example, 20 mm to 40 mm, or 22 mm to 38 mm, or 25 mm to 35 mm. Such dimensions of the fully expanded expandable basket can be suitable for placement in, for example, a cardiac cavity. For larger body cavities, the expandable basket can have larger dimensions, for example, 30 mm to 150 mm, or 40 mm to 120 mm, or 50 mm to 100 mm. In other situations, a fully expanded expandable basket with smaller dimensions may be suitable for smaller body cavities. Such smaller expandable baskets may have dimensions in the fully expanded state of, for example, 3 mm to 25 mm, or 5 mm to 15 mm, or 7 mm to 10 mm.

[0072] In some embodiments, rather than the filaments (415) braided into the braided mesh (413) being cut adjacent to the distal portion of the expandable basket (409), the filaments (415) can be bent at the distal portion and attached adjacent to the distal portion of the inner elongate shaft to form a terminal assembly. The bent filaments can then be directed back toward the expandable basket (409) or the outer elongate shaft, where they can terminate. Figure 6A shows an expandable basket (409) with bent filaments at its distal portion (603) in more detail.

[0073] Expandable baskets made from braided mesh have an advantage over prior art solutions with non-braided struts in that they have higher mechanical stability while using relatively thin filaments. Having more filaments in the structure can also allow for the use of more electrodes. The electrodes placed on the filaments can also be more optimally distributed, meaning, for example, that they can be placed closer together or desired patterns can be created in the expandable basket. Another advantage of expandable baskets made from braided mesh is the higher mechanical stability of the structure, which can ensure a stable and predictable distance between electrodes.

[0074] The braided mesh may be heat-treated to ensure deformation of the filaments and fixation of such deformation. Such deformed filaments then ensure that the filament intersections (points where filaments cross each other) remain relatively stable over the length of the filaments during expansion and collapse of the basket assembly (expandable basket). This means that the filament intersections remain relatively the same over long distances of the filaments in the collapsed and fully expanded states of the basket assembly (expandable basket). What changes is the mutual angle of the specific filaments forming the intersections (e.g., from about 2 degrees to 178 degrees, or vice versa). While some small longitudinal movements of the intersections may not be completely avoided by this process, they are limited to a degree that does not impair the dimensions and / or mechanical stability of the braided mesh. This feature may then enable, for example, the placement of electrodes at the filament intersections and / or ensure the electrodes' stable, predictable, and desired mutual positions and / or distances.

[0075] Further structural stability of an expandable basket made from a braided mesh can be achieved, for example, by joining certain filaments (contained in the braided mesh) together. The filaments can be joined to each other, for example, at their intersections. An exemplary solution can be seen in FIG. 20. The joints (2001) can be fixed (not allowing any mutual movement of the filaments at the joint) or interacting (allowing some kind of mutual movement of the filaments at the joint). Joining can be achieved, for example, by gluing, welding, laminating, bonding, tying (e.g., with some kind of string), or melting. Another option would be to tie the filaments together, for example, by a ring structure or crimping. If the ring structure is made of a conductive material (e.g., metal), it can also function as an electrode. The same applies to crimping. Metal connectors can also function as electrodes.

[0076] The meshes within the braided mesh need not be uniform in size; rather, the sizes of the meshes may vary. The size may increase, for example, from the distal and proximal portions of the expandable basket (which may be smallest) to the middle portion of the expandable basket (which may be largest). In other words, the mesh dimensions of the central body portion of the basket assembly may be larger than the mesh dimensions of the proximal and distal body portions of the basket assembly. The size may increase, for example, linearly or exponentially. The circumference of the mesh in the proximal and distal body portions may be, for example, between 1 mm and 40 mm, while the circumference of the mesh in the central body portion may be, for example, between 5 mm and 80 mm. The number of rows of mesh forming the complete braided mesh of the expandable basket may be between 4 and 40.

[0077] Two or more filaments forming the braided mesh, and thus the expandable basket, can be merged or joined together at their proximal and / or distal ends to form a merged structure (2101) in the proximal and / or distal portions of the expandable basket, as shown schematically in FIG. 21 . Such a solution can reduce the number of filaments in the proximal and / or distal portions of the expandable basket. Reducing the number of filaments entering related structures, such as the proximal portion of the expandable basket adjacent to the distal end of the outer elongate shaft and / or the proximal portion of the basket assembly, which may include attachments to the distal portion of the basket assembly, which may include a terminal assembly, can reduce the complexity and / or mechanical stability of those structures and thus the entire basket assembly. Because the number of components in a structure with a reduced number of filaments is reduced, it may even help reduce the risk of ablation procedures. Regarding filament length, the merged structure of the proximal or distal portion of the filaments can be 1% to 30%, or 3% to 20%, or 5% to 15% of the total length of the filaments included in the expandable basket. As mentioned above, the filaments can be merged at the distal or proximal ends, or both. When the filaments are merged at both ends, the merged lengths can be the same at both ends, or they can be different. The merged portions of the filaments at either the proximal or distal end of the basket can account for 1% to 35%, 4% to 25%, or 6% to 20% of the length of the expanded basket in the collapsed configuration. The filaments can be merged, for example, by bonding, welding, laminating, gluing, tying, or melting. Another option is to join the filaments together, for example, by some kind of tubular structure or by crimping. The tubular structure can be, for example, a tube made of metal or polymer, or a thermoplastic tube with a lumen. In this case, the ends of the filaments are threaded through the lumen of the tube and secured therein (e.g., by bonding, welding, laminating, gluing, tying, melting, or swaging), thus joining them to each other. Another option may be the use of a multi-lumen tube made of metal or polymer or thermoplastic, with each end of each filament to be joined being threaded through a separate (its own) lumen of the multi-lumen tube and secured therein (e.g., by gluing, welding, laminating, bonding, bundling, melting or swaging), and thus joined together.

[0078] The diameter of the filaments in the braided mesh may be 0.2 mm to 1 mm, or 0.4 mm to 0.8 mm, or 0.5 mm to 0.7 mm. The number of filaments braided into the braided mesh forming the expandable basket may vary from 5 to 150, or 10 to 60, or 15 to 50, or 16 to 32.

[0079] The filaments may be made from electrically insulating, non-conductive materials, such as nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or polymers or thermoplastic elastomers, such as silicone. The material may be further reinforced, for example, with glass fibers. The cross-section of the filaments may be circular, or other cross-sectional shapes are possible, for example, but not limited to, oval, circular, semicircular, rectangular, square, flat, or star-shaped. The filaments (415) may be formed from a tube having an at least partially hollow structure with a lumen (601), as seen in FIG. 6B, for example. Some or all of the filaments (415) may be hollow along their entire length, or, for example, the lumen (601) may be present only along a portion of the length of one or more filaments (415). Another embodiment may include a braided mesh (413) that includes a first subset of filaments (415) that include a lumen (601) and another subset of filaments (415) that do not have a lumen, or none of the filaments may have a lumen.

[0080] There are further options for increasing the mechanical stability of the filament. One of them is the use of multilayer walls. The walls of the filament can, for example, contain two or more layers of material. Materials with different properties can be used in combination to result in a more mechanically stable wall and therefore a more mechanically stable filament. Such combinations can use layers made of different materials, for example, from the group of polymers or thermoplastics, such as nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or silicone. Another possible option is the use of layers made of the same type of material, but with different subgroups of materials with different properties for each layer. The materials used for certain layers can be further reinforced, for example, with glass fibers.

[0081] In another embodiment, the filament may be configured to accommodate, for example, a mechanical support inserted into the lumen of the filament. The filament may be further mechanically reinforced by being reinforced with a strut. Such a mechanical support may be, for example, in the form of a strut disposed in the filament lumen. The strut may be disposed within the entire length of the filament or within the entire length of the filament lumen if the filament does not have a lumen along its entire length. Another possible option is to dispose the strut only along a portion of the entire length of the lumen, thus reinforcing part of the filament with struts and leaving another part without strut reinforcement. The strut may be made, for example, of nitinol, or may be made, for example, of an electrically insulating layer, such as polyamide (PA), polyimide (PI), or PTFE. Other possible materials suitable for the struts may be polymers or thermoplastics, such as nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or silicone.

[0082] Yet another suitable option for further reinforcing the filament is to fill at least a portion of the lumen of the filament with an adhesive or a molten polymer or thermoplastic material.

[0083] The braided mesh may then be configured such that all of the filaments contained in the mesh are reinforced, or such that only a portion of the filaments contained in the mesh include reinforcement, while another portion of the filaments may not include reinforcement.

[0084] At least one of the filaments forming the braided mesh can include at least one location where the structure of the filament is locally mechanically weaker than the rest of the filament. Such a location can form a so-called living hinge (2103), as shown schematically in FIG. 21 . A living hinge can be useful for defining a more or less precise location where the filament included in the braided mesh, and therefore the expandable basket, bends more easily, forming a smaller radius (or a more direct kink) than a filament without such a living hinge. This can further help define a more predictable shape of the deployed expandable basket in at least one of the deployed positions. Establishing such a living hinge in the filament can include thinning or cutting a portion of the filament. Thinning can be achieved, for example, by squeezing or thermoforming a specific location of the filament. Thinning can occur around the entire circumference of the filament or only partially. A partially asymmetric thinning can be advantageous, since the hinge thus formed can define a specific direction in which the filament is more likely to bend compared to other directions. In one example of an expandable basket, living hinges formed in the filaments can allow the filaments, and therefore the braided mesh, to be easily bent, for example, radially from the central longitudinal axis of the catheter. For example, living hinges that create a smaller radius or twist in the filaments in the region of the distal body portion (421) of the basket assembly body or the terminal assembly can help shape the expandable basket (basket assembly body) in a region distal to a plane that intersects with the basket assembly at its largest diameter (in one of its expanded configurations), so that at least a portion of the distal portion of the basket (region of the distal body portion) can form a larger angle (radially from the elongated axis) compared to the proximal portion of the basket (region of the proximal body portion).In extreme cases, the distal portion of the basket (region of the distal body portion) can form an angle of 90° or more (radially from the elongate axis) such that at least a portion of the expandable basket containing the electrodes is the longitudinally most distal portion of the catheter and achieves the expanded state without any other portion (e.g., the contact assembly) protruding more distally. Such a configuration can be advantageous, for example, in ablation of a relatively flat treatment site.

[0085] At least one living hinge, as described in the previous paragraph, may be included in at least a portion of the braided mesh where the filaments are merged together (in a merged structure). In this case, the living hinge is a location on the merged structure that is locally mechanically weaker than the rest of the merged structure and may be created, for example, by thinning or cutting the merged structure after merging. Another option for establishing a living hinge in the merged structure, particularly when the merged structure includes a polymer tube and filaments are merged into the lumen of the tube or into multiple lumens of a multi-lumen tube, is to pre-thin or pre-cut the polymer tube before inserting the filaments. Such pre-thinning of the tube can be achieved, for example, by squeezing, thermoforming, or molding, e.g., injection molding.

[0086] The living hinges can be formed in the distal, central, and / or proximal body portions of the basket assembly body. For example, if they are located in the proximal body portion, they can be located in a proximal region that is 0% to 20%, 0% to 15%, or 0% to 10% of the length of the folded basket. If they are located in the distal body portion, they can be located in a distal region that is 0% to 20%, 0% to 15%, or 0% to 10% of the length of the folded basket. They may also be part of the terminal assembly. If the hinge is located in the central body portion, it can be located on a plane that intersects the basket assembly, distal to the maximum diameter, or -20% to +20%, -10% to +10%, or -5% to +5% of this plane or the center of the folded basket.

[0087] The expandable basket can include one or more electrodes or a set of electrodes. The electrodes can be configured for at least one of generating an electric field for ablation of tissue or acquiring or transmitting electrical or other signals, such as signals for tissue mapping, ECG monitoring, impedance measurement, and / or detecting contact with tissue. Another function of the electrodes can be to serve as markers for X-rays. Electrodes can be coupled to specific filaments of the expandable basket. Electrodes can be disposed on each filament or on only a portion of the filaments. Each electrode-containing filament can include one or more electrodes, for example, 1 to 15, 1 to 10, 1 to 6, or 1 to 3 electrodes. The electrodes can be of one type or different types. The total number of electrodes disposed on the expandable basket can be 1 to 200, 5 to 100, 10 to 50, 15 to 40, or 20 to 35. The spatial distance between the electrodes in the fully expanded configuration of the expandable basket can be between 0.1 mm and 15 mm, or between 0.5 mm and 10 mm, or between 1 mm and 6 mm, or between 2 mm and 4 mm.

[0088] In examples, electrodes may be positioned at regions where filaments cross one another (filament crossing points). Such locations may be advantageous due to the ability to maintain a more stable distance between electrodes during different configurations of the expandable basket, and such configurations may also advantageously prevent undesired contact between electrodes, particularly when the expandable basket is not in a fully expanded configuration.

[0089] Each filament may also contain one or different types of electrodes, or different filaments may house different types of electrodes. Different types of electrodes may be understood as electrodes with different functions, such as ablation electrodes, measurement electrodes, etc., or physically different electrodes, e.g., with different shapes, sizes, designs, materials, etc., or combinations of types of electrodes with different functional and physical properties. For example, in a configuration with ring-shaped electrodes arranged on a filament, all electrodes may have the same diameter but may have different lengths, so that there may be, for example, two or more groups of such electrodes, each group having a different length. The number of electrodes in each group may be the same or different. In extreme cases, each electrode of the expandable basket may have a different length. In configurations with ring electrodes, such electrodes may have a diameter of 0.2 mm to 3 mm, or 0.4 mm to 2 mm, or 0.5 mm to 1 mm, and a length of 0.1 mm to 10 mm, or 0.2 mm to 8 mm, or 0.3 mm to 6 mm, or 0.4 mm to 4 mm.

[0090] In one example, there may be a first group of 5 to 20 shorter electrodes, e.g., having a length of 0.3 mm to 3 mm, and a second group of 5 to 30 electrodes, which may be longer, e.g., having a length of 0.6 mm to 4 mm. Advantageously, electrodes from the first group may be used for at least one type of measurement, e.g., intracardiac ECG (EGM) measurement, or ablation, and electrodes from the second group may be used for ablation, either independently or in combination with electrodes from the first group.

[0091] Electrodes can be positioned on the body of the basket assembly. For example, electrodes can be positioned on the central or distal body portion, and in some cases, electrodes can even be positioned on the proximal body portion. Other electrodes can be positioned on or within the outer elongate shaft, inner elongate shaft, catheter distal tip, or terminal assembly. In configurations where electrodes are positioned on the elongate shaft, distal tip, or terminal assembly and ring electrodes are used, they can have a diameter of 0.2 mm to 10 mm, or 0.5 mm to 8 mm, or 1 mm to 6 mm, or 2 mm to 5 mm, and a length of 0.1 mm to 20 mm, or 0.2 mm to 15 mm, or 0.3 mm to 12 mm, or 0.4 mm to 10 mm.

[0092] The layout of the electrodes on the expandable basket can ensure a continuous, eg, circular, ablation area while the expandable basket is in the expanded position, and a pattern can be created.

[0093] For example, the layout of the electrodes in the expandable basket can ensure a continuous circular ablation area, and patterns can also be created, even while the expandable basket is held in various expanded positions between the fully collapsed position and the fully expanded position.

[0094] Additional electrodes, such as those located on or within the outer elongate shaft, inner elongate shaft, catheter distal tip, or terminal assembly, may be part of the pattern or may be operated independently of the other electrodes. For example, electrodes in the region of the distal tip or terminal assembly of the catheter may be used for point ablation. There may be special, dedicated electrodes in the region of the distal tip or terminal assembly, or, for example, metal components of the terminal assembly may function as electrodes, or a combination thereof may be possible.

[0095] The pattern (701) generated by the electrodes (109) may be, for example, a circular pattern in space around the central longitudinal axis (203) when the expandable basket (409) is in one of its expanded configurations, as seen at least in FIG. 7A. Other two-dimensional or three-dimensional patterns generated by the electrodes (109) are also possible. The pattern (701) may or may not be centered around the central longitudinal axis (203). The pattern (701) may have different shapes, including, but not limited to, circles, ellipses, squares, rectangles, polygons, planes, etc., or the arrangement of the electrodes (109) on the expandable basket may be irregular. For example, there may be one pattern (701) in one plane, more patterns (701) in one plane, or more patterns (701) in different planes.

[0096] The pattern generated by the electrodes can be disposed on the basket assembly body, particularly the distal, central, or proximal body portions, as shown in FIG. 7B. The pattern may extend through two or more of these portions. For example, for treatment of a flat treatment site located distally from the basket assembly, the electrode pattern may be advantageously disposed on the distal portion of the basket assembly. In particular, the pattern may be disposed on a portion of the basket assembly surrounded by a region that forms an angle (703) of 0° to 90° with respect to the central axis (203) at the center of a plane (425) that intersects the basket assembly at the portion of the basket assembly having the largest diameter (in one of the expanded configurations). In some configurations, the pattern may be disposed partially on the distal portion of the basket assembly body and partially on the central portion of the basket assembly body. In some configurations, the pattern may be disposed on a section of the basket assembly surrounded by a region that forms an angle (705) of 0° to 120° with respect to the central axis (203) at the center of the plane (425). Such pattern placement may be particularly advantageous for treatment of a blood vessel opening, such as the ostium of a pulmonary vein. In situations where the treatment site has a tubular shape, the pattern may be disposed in the intermediate portion of the basket assembly, particularly in the portion of the basket assembly bounded by a region that forms an angle (707) of 45° to 135° with respect to the central axis (203) at the center of the plane (425). When a flat treatment site is disposed proximal to the basket assembly, e.g., the septum, the electrode pattern may be disposed in the proximal body portion of the basket assembly, or partially in the proximal body portion and partially in the central body portion, particularly in the portion of the basket assembly bounded by a region that forms an angle (709) of 90° to 180° with respect to the central axis (203) at the center of the plane (425). Optionally, electrodes may be disposed in all portions of the basket assembly, thus creating patterns in all portions and selecting only those patterns necessary or optimal for performing a particular treatment.

[0097] A particular pattern can be created using all of the electrodes in the expandable basket, or only a portion of the electrodes. The pattern can have different numbers of electrodes in various expanded positions between the fully collapsed and fully expanded positions of the expandable basket. Adjacent electrodes in the pattern can have a distance between each other of, for example, 0.1 mm to 15 mm, 0.5 mm to 10 mm, 1 mm to 6 mm, or 2 mm to 4 mm.

[0098] The electrodes are electrically connected to the pulse generator, for example, by conductive wires. The electrodes may be electrically or communicatively connected to other units or portions of the pulse field ablation device, as well as to other units or portions of the device, such as a mapping device, an EP display device, a pacing device, an ECG recording device, a catheter signal interconnect circuit, an ECG trigger circuit, an electrical control circuit, a GUI unit, or a remote control unit. Aside from the ring-shaped electrodes described above, the electrodes may have any of many different shapes, such as a tube threaded around the filament, a coiled metal sheet, a square and / or rectangular shape, or other shapes of conductive material attached to the filament. Another possible form of the electrode (109) may be an elongated continuous electrode drawn along the surface of a portion of the filament (415) of the braided mesh (413) so as not to contact the filament (415) at their intersections, as shown in FIG. 8 . The electrode (109) may be attached to a particular filament (415) of the expandable basket by any means, such as mechanical attachment, swaging, crimping, adhesive bonding, lamination, deposition, and / or soldering. The electrodes can be made of any conductive material, such as copper, gold, steel, titanium, platinum, platinum-iridium, etc. If there is at least one filament made of a conductive material, it can also function as an electrode. If the entire conductive filament is not insulated, the entire filament may function as an electrode, or if the filament is, for example, partially electrically insulated, the bare, uninsulated portion may function as an electrode. You may do so.

[0099] The conductive wires can provide electrical connection between the electrodes and the pulse generator. The conductive wires can be part of the structure of the basket assembly (401). For example, the conductive wires (417) can be at least partially disposed in the lumen (601) of the filament (415), as shown in FIG. 6C or FIG. 9. There can be one or more conductive wires (417) coupled to each of the electrodes, or one or more electrodes can be coupled to a single puller wire. The conductive wires (417) can be incorporated into one of the walls of the shaft assembly, for example, the wall of the outer elongate shaft. The conductive wires can also be disposed in a central lumen of the outer elongate shaft, or there can be a separate lumen in the outer elongate shaft suitable for conductor placement. The conductive wires can terminate adjacent to the electrodes or extend spatially further along the length of the filament beyond the electrodes. The conductive wires can be disposed, for example, along the entire length of the filament of the basket assembly. Optionally, some of the conductive wires (417) can terminate adjacent to the electrodes, while others can be led spatially further along the filament beyond the electrodes, or can be positioned along the entire length of the filament of the basket assembly.

[0100] When the conductive wire is disposed along the entire length of the filament, an expandable basket design solution in which the filament is bent at the distal end of the expandable basket and returned to the expandable basket rather than severed is particularly advantageous. Because certain conductive wires are configured to carry electrical pulses between the electrode and the pulse generator, insulating the severed filament from the inner conductive wire can be extremely difficult in a terminal assembly. However, in examples with bent filaments with internal conductive wires, the insulation of the terminal assembly can be easily ensured.

[0101] The material used for the conductive wire can be any conductive material, such as copper, stainless steel, steel, nitinol, aluminum, gold, platinum, or silver. The conductive wire can be insulated or uninsulated. The wire can be insulated using any suitable material, such as polyimide, polyurethane, polyester, polyvinyl chloride (PVC), rubber, rubber-like polymers, nylon, polyethylene, polypropylene, silicone, fiberglass, or different fluoropolymers, such as ethylene propylene diene monomer (EPDM) or polytetrafluoroethylene (PTFE). The wire can be made with a single conductor or groups of conductors, but wires made with groups of conductors are sometimes called "cables." If the wire is insulated, the minimum breakdown voltage of the wire insulation should be at least 100 V, 500 V, 1000 V, 4000 V, or 10,000 V. The diameter of the wire with insulation can be limited by the dimensions of other structures in the device, such as the filament, and the minimum voltage it must be able to withstand without risk of failure. Typical diameters of the wire, with or without insulation, can be between 0.05 mm and 0.7 mm, or between 0.07 mm and 0.5 mm, or between 0.1 mm and 0.3 mm, or between 0.11 mm and 0.2 mm, or between 0.12 mm and 0.18 mm.

[0102] Constructing a braided mesh from an electrically insulating material, such as that described above with one or more conductive wires within a hollow filament, can be particularly advantageous for ablation systems based on the principle of pulsed field ablation using pulsed electric fields. As further described, pulsed field ablation methods require an electric field generated around an electrode. To generate the field, an electrical pulse must be carried by a specific conductive wire between the electrode and a pulse generator. If the filament is non-conductive and the conductive wire is held inside the filament as described herein, electrical insulation of the specific conductive wire can be ensured even at voltage levels of several kV, e.g., 1 kV to 10 kV, carried by the conductive wire. However, fabrication of a braided mesh from an electrically conductive material (e.g., nitinol, copper, stainless steel, steel, aluminum, gold, platinum, or silver) can be difficult. A braided mesh with at least one or more conductive filaments may also be an option. Such conductive filaments may be insulated, uninsulated, or only partially insulated. They may not only potentially conduct current, but also (if uninsulated or only partially insulated) may act as electrodes and / or as additional mechanical support for the braided mesh and thus the expandable basket.

[0103] Another advantage of braided meshes made from polymer or thermoplastic elastomer filaments is their ease of manufacture compared to, for example, metal braided meshes. Braided meshes can be fabricated, for example, using a three-dimensional mandrel apparatus. The specific filaments forming the mesh can be arranged on the mandrel in a desired pattern. The filaments may already contain conductive wires. The entire structure can then be heated, for example, near the melting point of the filament material, and the structure can then be rapidly cooled. Because filaments made from thermoplastic elastomers or polymers generally require lower temperatures to reach their melting point than most metals, the manufacturing process can be faster, more efficient, and require less energy input. Another advantage of such a manufacturing process is that the conductive wires do not need to be heated to extreme temperatures, which could damage the wire's electrical properties. This situation can arise, for example, when the braided mesh is made from metal wires and the mesh wires also function as conductive wires.

[0104] The braided mesh with inserted conductive wires can be attached to the outer and inner elongate shafts to form an expandable basket and part of the basket assembly. Electrodes can be attached to specific filaments of the braided mesh before or after the braided mesh is attached to the elongate shafts. The pulse generator is the part responsible for generating the electrical signal for the catheter electrodes. The pulse generator can, for example, allow for setting the amplitude, shape, and / or number of electrical pulses during activation. The pulse generator can also diagnose the electrical waveform to measure power. The pulse generator can allow for synchronized operation with an ECG device or another part of the ablation system or device.

[0105] Additionally, methods of ablation using the described pulsed field ablation devices are disclosed.

[0106] One method includes positioning a catheter (105) adjacent to a treatment site, such as a heart chamber, in a patient via a blood vessel. The catheter (105) may be inserted percutaneously into the patient's blood vessel.

[0107] Other support structures and / or devices can be used to help navigate the distal tip of the catheter to its desired location. Examples of such devices include a guidewire or a sheath. The distal tip of the catheter can be delivered proximal to the treatment site in a collapsed state, for example, via a sheath. In the collapsed state, the diameter of the basket assembly at the distal tip of the catheter can be smaller than or approximately equal to the diameter of the outer elongate shaft of the catheter. Such a configuration allows for easy access of the distal tip of the catheter proximal to the treatment site.

[0108] The treatment site may be located, for example, within the body, for example, within or on the surface of the heart, for example, within a cardiac cavity, particularly, for example, within the left atrium of the heart. The treatment site may include, for example, the ostium of a pulmonary vein. Other locations of the treatment site may be, for example, any tubular tissue, organ, or blood vessel within the body, or, for example, the site of a tumor.

[0109] Once the catheter distal tip is delivered to the treatment site, the catheter's basket assembly unfolds from a collapsed or semi-collapsed configuration to one of its expanded configurations. This unfolding can be caused by the shape of the braided mesh or pretensioning of its filaments, by linear displacement of the inner elongate shaft relative to the outer elongate shaft along the catheter's central longitudinal axis, by tensioning of an additional support structure, such as an inner coil or balloon (not shown), or a combination thereof.

[0110] The catheter distal tip (107) may then be positioned adjacent to the target tissue at the treatment site (1001), such as at least a portion of the basket assembly (401), and / or a portion of the expandable basket (409) may be in contact with the treatment site (1001). In this position, at least a portion of the set of electrodes (109) disposed on the basket assembly (401) may be in contact with the tissue at the treatment site (1001). A schematic diagram of an exemplary position can be seen in FIG. 10. The contact assembly (411) can improve contact between the electrodes and the treatment site by having a flat design without distally protruding structures. When the basket assembly (401), particularly the basket assembly distal portion (405), does not have any distally protruding structures, it is easier to contact the electrodes with the treatment site, even when the treatment site is relatively flat.

[0111] After positioning the catheter distal tip adjacent to the treatment site, optional measurement steps can be performed with or without the catheter. Various types of measurements can be performed, for example, to diagnose the type or quality of tissue at or around the treatment site, the spatial location of the catheter distal tip, particularly relative to the treatment site, the contact of the catheter distal tip and / or specific electrodes with target tissue at the treatment site, or to understand electrophysiological processes in tissue adjacent to the electrodes. For example, electrodes can also be used to measure contact with target tissue and can be placed on the filaments of an expandable basket, e.g., a braided mesh. The measurement electrodes can be separate from the ablation electrodes, or the ablation electrodes can be used for measurements. Separate measurement electrodes can also be combined with the ablation electrodes, which have measurement capabilities, in a single catheter distal tip. To perform the measuring step, a separate measuring device can be used, such as a separate measuring catheter (not shown), an ECG device including an ECG trigger circuit, an ECG recording device, ECG electrodes, an intracardiac ECG (EGM), an intracardiac echo device, an esophageal temperature measuring device, a fluoroscopy device, an RTG device, an MR device, etc. The measuring step may be performed once or may be repeated several times during the ablation procedure.

[0112] Ablation of the target tissue at the treatment site (1001) uses the principle of pulsed field ablation, e.g., caused by a pulsed electric field of appropriate parameters. Although the terms "electric field" or "pulsed electric field" are referred to herein, the electric fields contemplated herein may further include a magnetic component.

[0113] The basket assembly deployment, measurement, and ablation procedures can be performed in several stages. For example, the expandable basket can be delivered adjacent to the treatment site in a fully collapsed configuration. After delivery, it can be deployed to a first expanded configuration. For example, a pretensioned shape of the braided mesh and / or filaments can trigger this first transition. In this configuration, for example, further manipulation with the basket assembly, as well as measurement and / or ablation, can be performed. Further repositioning, measurement, and / or ablation can also be performed in any order at this location.

[0114] The basket assembly can then be deployed to a second expanded configuration, for example, by extending the inner elongate shaft relative to the outer elongate shaft along the central longitudinal axis of the catheter. This can be achieved by linear displacement of the long shaft. In this configuration, for example, further manipulation of the basket assembly, as well as measurement and / or ablation, can be performed. Further repositioning, measurement and / or ablation can also be performed in any order at this location.

[0115] The basket assembly can, for example, be deployed to several different expanded positions during which further repositioning, measurement, and / or ablation can be performed.

[0116] In the case of pulmonary vein isolation ablation, a set of electrodes can create a circular shape around the pulmonary vein ostium. After ablation, the shape of the ablated tissue may have a circular shape around the pulmonary vein ostium. By repositioning the basket assembly or by switching between different electrodes, several such shapes of ablated tissue can be created.

[0117] The pulsed electric field (PEF) can be generated, for example, by electrical pulses, e.g., high-frequency electrical pulses. The electrical pulses can be generated by a pulse generator and delivered to the target tissue by electrodes positioned at the distal tip of the catheter and in electrical contact with the pulse generator. Electrical pulses can be generated by a variety of electrical pulses, ranging from monophasic (single-polarity) pulses to symmetric and / or asymmetric biphasic pulses. Pulses may be combined with extra pre-pulses or extra measurement pulses for tissue conditioning. Pulses can be single pulses or repeated in trains, where pulse parameters may vary or remain constant. Trains of pulses can also be performed in sequences. The maximum amplitude of the pulses can generate an electric field with a maximum electric field strength of, for example, 0.1 kV to 10 kV, 0.4 kV to 5 kV, or 0.5 kV to 2 kV per centimeter of the target tissue volume, depending on the target tissue, electrode size, and / or electrode distance. The pulse duration can be in the nanosecond to millisecond range, e.g., 2 ns to 10 ms, or 10 ns to 5 ms, or 10 μs to 1 ms. The pulse shape can be, for example, square, exponentially-like, rectangular, sawtooth, triangular, or sinusoidal.

[0118] Pulses can be monophasic or biphasic. Biphasic pulses can be symmetric or asymmetric. Pulses can be repeated from 1 to 100,000 times. The frequency of the high-frequency pulses can vary from 0.1 Hz to 10 Hz. The amplitude (Um) of monophasic pulses can vary from 100 V to 10 kV, and the peak-to-peak amplitude of biphasic pulses can vary from 200 V to 20 kV.

[0119] Figure 16 can serve as an example of a possible portion of a pulsed field ablation (PFA) protocol and as a clarification of terminology and expression related to PFA protocols. A PFA protocol includes a series of electrical pulses (1601) and pauses (1603, 1607, 1615). The electrical pulses (1601) can be further organized into units with specific hierarchies, such as trains (TR) and bursts (B).

[0120] The electrical pulses (1601) can be defined, for example, by their shape, amplitude (Um) at a particular voltage, and pulse length with duration (t1). The pulse amplitude (Um) can be either negative or positive in the case of monophasic pulses (pulses can have negative or positive voltages). The electrical pulses (1601) can be separated from each other by inter-pulse pauses (1603) defined by duration (t2) and voltage (Up). The voltage during the inter-pulse pauses (1603) can drop to 0 V or can have a positive or negative voltage value (Up). The absolute voltage value (Up) of the inter-pulse pause is less than the absolute voltage (amplitude (Um)) of the adjacent electrical pulse (1601), in particular up to 50% of the amplitude (Um) of the adjacent electrical pulse. In situations where the electrical pulses have a positive amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) remains positive between 0 V and the amplitude (Um) of the electrical pulse (1601), and in situations where the electrical pulses (1601) have a negative amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) remains negative between 0 V and the electrical pulse amplitude (Um). An example of an inter-pulse pause (1603) having a voltage different from 0 V is shown in Figure 17a. Biphasic pulses may be symmetric or asymmetric in at least one of time, amplitude, or energy.

[0121] An example of a biphasic electrical pulse is shown in Figure 17b. A biphasic pulse can have the same amplitude (voltage) of the positive phase (1701) and the negative phase (1703) with the same duration (t10, t12) of both phases (exemplary pulses A, D), or the amplitude and / or duration (t10) of the positive phase and the amplitude and / or duration (t12) of the negative phase can be different (exemplary pulses B, C). The resulting pulse can then have the same energy in the positive and negative phases of the pulse, or the energies of the positive and negative phases of the pulse can be different. A biphasic pulse with the same energy in both phases is sometimes called a symmetric biphasic pulse. A symmetric biphasic pulse can be balanced (if the duration and amplitude of both phases of the pulse are identical) or unbalanced (if the amplitude and / or duration are different for each phase). An asymmetric biphasic pulse has phases with different energies. Exemplary biphasic pulses A, B, and C have no pause between certain phases of the pulse (interphase pause), and exemplary pulse D is a biphasic pulse with an interphase pause (1705). The duration of the interphase pause of the pulse can be 0 μs to 50 μs, or 0 μs to 10 μs, or 0 μs to 5 μs.

[0122] A consecutive set or series of pulses, with or without inter-pulse pauses, may be referred to as a train (TR). Particular trains (TR) may be characterized, for example, by duration (t4) or number of pulses, and may be separated from one another by inter-train pauses (1607) having duration (t5), or inter-train pauses (1607) may separate trains with individual single pulses. A set or series of trains (TR) and inter-train pauses (1607) may be referred to as a burst (B), and may be characterized, for example, by duration (t6), number of trains (TR), number of pulses, or inter-burst pauses (1615) (having duration (t7) between particular bursts (B)).

[0123] As already mentioned above, the value of the voltage at the electrodes (Up) does not have to be reduced to 0 V between pulses, especially during the interpulse pause (1603), but can remain at a level such that the risk of generating bubbles due to electrolysis or temperature rise is nonexistent or very small, for example up to 50% of the amplitude (Um) of the adjacent electric pulse. This may also reduce unwanted relaxation of polar molecules, potentially shortening the length of at least some parts of the PFA protocol and therefore increasing the effectiveness of PEF therapy.

[0124] When pulses with amplitudes (Um) of hundreds to thousands of volts are applied, even if they are applied to the atria, there is a certain risk of depolarizing the ventricular muscle and causing undesired ventricular rhythms in the heart. Depolarization can be caused directly by an electric field or by secondary energy induction in another device, such as a catheter, placed in or near the atria or ventricles or both. Timing the active sequence (individual pulses, trains, and / or bursts) with a pause, as described below, has an effect called overdrive. The overdrive effect is commonly used in ablation catheterization procedures to reduce the risk of undesired cardiac rhythms by using an external pacemaker. An advantage of the proposed PFA protocol is that if the therapeutic (ablation) electrical pulse causes myocardial depolarization, it can also act as a pacing pulse to the heart, eliminating the need for an additional pacing device (e.g., an external pacemaker) to synchronize the pacing device pulse with the therapeutic pulse of the PFA protocol. This means that in this case, there is no need to use a pacing device to control the number of ventricular contractions per minute, detect individual ventricular contractions from the surface ECG, and then trigger ablation pulses accordingly.

[0125] The duration (t8) of one cycle (1609) of a burst (B), and the inter-burst pause (1615) between bursts, which can be between 201 ms and 800 ms, are determined by the range between the need to deliver pulses safely faster than the patient's actual heart rate (overdrive effect) and the need to maintain the heart rate at a safe level (roughly stated as 220 beats per minute minus age). The cycle duration can be fixed or variable within a prescribed range (201 ms to 800 ms) within the PFA protocol, for example, according to a sinusoidal or trigonometric function. Individual bursts (B) can have a duration (t6) of 1 ms to 200 ms, 30 ms to 180 ms, or 60 ms to 160 ms, which is a safe time for the applied burst of pulses (B) to contract the heart chambers and protect the ventricles from damage or undesirable rhythms. The burst (B) duration (t6) can also be fixed or variable in the described range (1 ms-200 ms) within the PFA protocol, for example according to a sinusoidal or trigonometric function.

[0126] This PFA protocol may have other positive effects on the ablation outcome, for example, reducing the risk of inducing undesired ventricular rhythms and / or maximizing the efficiency of PEF application.

[0127] However, although electroporation has been described as the main trigger of cardiomyocyte death after the application of PEF, actual cell death can instead be caused, for example, by electrical disruption of cardiomyocyte, mitochondrial, or nuclear membranes; by separating individual cells / cardiomyocytes (or cell groups) of the myocardium (e.g., by damaging intercalated discs or by mechanical damage due to a direct electric field, or hypercontraction); by damage to myofibers or myofibrils; by ATP depletion and insufficient production in cardiomyocytes due to hypercontraction; by loosening of intercellular junctions of cardiomyocytes; by myolysis of myocytes; by crumpling of cardiomyocytes directly under the influence of an electric field or by mechanical damage due to hypercontraction; by irreversible damage to the calcium cycle (whether due to non-physiological function of the sarcoplasmic reticulum, ion pumps, calcium channels, or calcium-binding proteins); by calcium overload of the myocardium - mitochondrial swelling (as a result of hypercontraction or damage of the cardiomyocyte sarcolemma or non-physiological function of calcium channels); or by the formation of reactive oxygen species (ROS) and subsequent oxidation of membrane phospholipids by PEF.

[0128] The electric field can be generated between one or more electrodes located at the distal tip of the catheter and a separate electrode, for example, located remotely on the patient's skin. The separate electrode may, in some embodiments, have a surface significantly larger than the combined surface area of the active distal tip electrodes. This mode of operation is typically referred to as monopolar. Another option for generating the electric field is bipolar mode, in which the electric field is generated between two or more, usually closely spaced or adjacent, distal tip electrodes of different polarities. In this case, the combined surface area of the active electrodes with one polarity is similar to the combined surface area of the active electrodes with the second polarity.

[0129] In some embodiments, the electrodes (109) located on the distal assembly can operate in a hybrid mode between the previous two types. An example of such a configuration is shown in FIG. 11. In this mode, only the electrodes (109) located on the distal tip (107) are used for ablation. A first single electrode or group of electrodes operates in a mode with a first polarity (P1) and a second electrode or group of electrodes operates in a mode with a different polarity (P2, opposite polarity) from the operating mode of the first electrode or group of electrodes. There may be a second single electrode or group of electrodes operating in a mode having a polarity of 0.1 or 1.2 (or 0.2 or 1.3). The surface or total surface of the first electrode or first group of electrodes is significantly smaller than the surface or total surface of the second electrode or group of electrodes. For example, there may be a third group of electrodes operating in a third mode in a high impedance (HI) state, where the impedance of the electrodes in the third group is higher than, for example, 500 Ω. The electrode operating in the third mode may be adjacent to the electrode or group of electrodes operating in the first mode.

[0130] One advantage of operating the electrode in this hybrid mode is that the generated electric field has a more uniform current density compared to the bipolar mode. Another advantage of the hybrid mode of operation is that the electric field generated in this mode can, in some embodiments, reach deeper into the target tissue compared to the bipolar mode. For cardiac cavity ablation, the depth of the ablated target tissue (in one example, the target tissue may include myocardial tissue) can be up to 5 mm.

[0131] A variant of the hybrid operating mode of the electrode (109) with a group of electrodes (two or more electrodes) operating in a mode with a first polarity (P1) is shown in Figure 12. The functional principle of this operating mode is similar to the variant in which one electrode (109) operates in a mode with a first polarity (P1). For example, the total surface of the electrodes operating in a mode with a first polarity (P1) is significantly smaller than the total surface of the electrodes operating in a mode with a different polarity (P2).

[0132] An example of a group of electrodes (two or more electrodes) operating in a mode having a first polarity (P1) may be advantageous over an example of a single electrode operating in a mode having a first polarity (P1), for example, in situations where reducing the size of the electrode is advantageous. Reducing the size of the electrode may be advantageous or necessary when increasing the number of electrodes is necessary or desirable. For example, a larger number of electrodes is desirable when more precise mapping of the treatment site or more precise and / or more uniform ablation of target tissue at the treatment site is desired. Because the treatment site may be part of the human anatomy, the overall size of the pulsed field ablation device, particularly a catheter having a catheter distal tip, must be limited in accordance with the human anatomy. Therefore, if more electrodes are required for the ablation device, for a certain number of electrodes, the size of the electrodes must be limited so as to fit within the limited dimensions of the critical parts of the pulsed field ablation device, such as the catheter and / or its distal tip and / or its basket assembly. Another advantage of smaller electrode size is that such a configuration can help increase the depth of ablation.

[0133] Smaller electrode sizes can have other advantages, for example, in instances where the same electrode is used for ablation and for measurement, the same electrode must be configured to deliver the high-voltage pulse and record the measurement. For example, in measuring ECG signals, smaller electrodes may be advantageous.

[0134] However, there are also some challenges associated with smaller electrodes. In examples involving pulsed field ablation, the electric field is generated, for example, by an electric pulse, e.g., a high-frequency electric pulse generated by a pulse generator. For effective ablation of the entire target area of the treatment site, it may be important to generate an electric field with a maximum electric field amplitude of several hundred volts to several kilovolts per centimeter for the target tissue volume. Using smaller electrodes means a smaller surface area of the electrode. If the surface area of the electrode is smaller, the voltage induced in the electrode must be higher compared to a larger electrode with a larger surface area to achieve the desired electric field density in the target tissue. Negative effects of such a configuration include a higher density electric field, a higher intensity electric field, and / or a higher voltage at the edge of the electrode. These problems may include the possibility of sparks. However, by using a group of selected electrodes (two or more electrodes) operating in a mode with a first polarity instead of a single electrode operating in a mode with a first polarity, some or all of these issues can be addressed and overcome. With a first group of well-selected electrodes operating in a mode with a first polarity, a second group of electrodes operating in a mode with a different polarity, and possibly a third group of electrodes operating in a third mode in a high-impedance state, the first group of electrodes and / or the second group of electrodes can function as virtual electrodes. That is, the electrodes of the first group can act together as one virtual electrode and / or the electrodes of the second group can act as another virtual electrode. This configuration can reduce the strength and / or density of the electric field near the electrodes. Other positive effects of this configuration can be a reduced risk of sparks and increased ablation depth, or increased depth of ablated tissue at the treatment site.

[0135] The increase in the surface area of the electrodes in the first group, and the resulting creation of virtual electrodes, can result in a reduction in the voltage that needs to be induced on the electrodes and / or the elimination of sparks primarily at the edges of the electrodes. However, the concept of disproportional surface areas of the electrodes in the first and second groups of electrodes can be preserved, meaning that the surface area or sum of the surface areas of the first electrode or first group of electrodes is significantly smaller than the surface area or sum of the surface areas of the second electrode or group of electrodes. The ratio of the surface area or sum of the surface areas of the electrodes in the first group to the sum of the surface areas of the electrodes in the second group of electrodes can be 2:3 to 1:100, or 3:5 to 1:80, or 3:5 to 1:70, or 1:2 to 1:50, or 1:2 to 1:40, or 1:2 to 1:30, or 1:2 to 1:20, or 1:3 to 1:15, or 1:3 to 1:10, or 1:4 to 1:8.

[0136] Adding an electrode to the first group of electrodes operating in a mode with a first polarity can significantly reduce the strength of the electric field near the electrode. For example, using four electrodes instead of one electrode in the first group of electrodes operating in a mode with a first polarity reduces the strength of the electric field at the electrode surface by a factor of four, while in an example where three electrodes are used, the strength of the electric field is reduced by a factor of two. This reduction in strength can allow the use of lower voltages on the electrodes compared to a solution with only one electrode operating in a mode with a first polarity. Additionally or alternatively, the reduction can be as low as 1 cm. 2 By increasing the area of the electric field at a constant voltage per cm, the depth of the ablated target tissue can be increased. 2 The voltage per unit area is, for example, 50V / cm 2 ~3000V / cm 2 , or 100V / cm 2 ~1500V / cm 2 , or 250V / cm 2 ~1000V / cm 2 may be.

[0137] Certain electrodes at the distal tip of the catheter can be switched to one or more modes during ablation. They can be switched during a single ablation cycle or several ablation cycles. Electrodes may be switched to one or more modes several times during a single ablation cycle or several ablation cycles. In some embodiments, it is even possible to have two or more groups of electrodes simultaneously operating in a mode with a first polarity and other groups of electrodes operating with different polarities, with or without electrodes operating in a high impedance state.

[0138] The layout or spatial pattern of the electrodes at the distal tip can be created to allow for hybrid modes of operation of the electrodes and / or for the purpose of creating virtual electrodes. Because the electrodes can be switched to one or more modes during ablation, the resulting virtual electrodes can have different spatial shapes, which means that the electric fields generated around and between the virtual electrodes can have different shapes with different configurations of magnetic fields and / or different densities and strengths of electric fields. The distal tip, specifically the expandable basket Examples of spatial patterns of electrodes can be seen in Figures 13A and 13B. Figure 13A shows a front view of a basket assembly (401) having a spatial pattern of electrodes (109) suitable for creating virtual electrodes by switching the electrodes (109) to a first polarity and different modes of operation with different polarities and / or high impedance states.

[0139] Figure 13B again shows a front view of the basket assembly (401) with a spatial pattern of electrodes suitable for creating virtual electrodes by switching the electrodes (109) to different modes, but this time the electrodes are positioned in areas where the filaments (415) cross each other (filament crossing points).

[0140] An example of a possible layout of electrodes already switched into a hybrid operating mode can be seen in Figure 14, which is also a front view of the basket assembly (401). A first group of electrodes (109) are operating in a mode having a first polarity (P1) and together form a first virtual electrode (1401). Another group of electrodes (109) are operating in a mode having a different polarity (P2) and together create a second virtual electrode (1403). In this configuration, when an electrical pulse is delivered from the pulse generator (103) to the electrodes (109), an electric field is generated between and around the virtual electrodes (1401, 1403). Some of the electrodes (109) may be operating in a third mode, e.g., in a high impedance (HI) state.

[0141] Electrodes in a high-impedance state (higher than 500 Ω) can help shape the electric field generated between and around electrodes from the first group of electrodes and the second group of electrodes, and / or between or around virtual electrodes. In one example, assigning a high-impedance state to electrodes spatially adjacent to electrodes operating in a mode with a first polarity can have a positive effect on the shape of the electric field, such that a portion of the electric field capable of causing ablation reaches deeper into the target tissue at the treatment site, compared to an operating mode without electrodes in a high-impedance state. This phenomenon can have a positive effect on the quality and uniformity of the ablation procedure. Electrodes in a high-impedance state can be spatially positioned between the first group of electrodes and the second group of electrodes.

[0142] An exemplary pattern of electrodes (109) is shown in more detail in FIG. 15A. The electrodes (109) create a repeating cross, square, or rectangular pattern on the filaments (415) of the braided mesh in one of the expandable basket's expanded configurations. From this view, perpendicular to the tangent plane (e.g., contacting the expandable basket at the intersections (1501) of four adjacent electrodes), the pattern appears two-dimensional, but is actually three-dimensional because the electrodes (109) are fixed to or are part of the filaments (415) of the braided mesh, forming the expandable basket, and therefore the pattern conforms to the curvature of the expandable basket. This pattern of electrodes is advantageous in embodiments using a group of electrodes operating in a mode having a first polarity (P1). In this example, the group of four adjacent electrodes operating in a mode having a first polarity (P1), thus creating the first virtual electrode (1401), has either a cross shape as shown in FIG. 15A, or a square or rectangle as shown in FIG. 15B. The advantage is that both virtual electrodes (1401) generated by both shapes can be combined with a second virtual electrode, possibly prompted by an electrode in a high impedance state, to generate an electric field with specific qualities (potential shape, magnitude, density, gradient) suitable for ablation of the target tissue.

[0143] 15C shows an example of an electrode pattern in which electrodes (109) are placed at the regions where filaments (415) cross each other (filament intersections). Also shown here is a group of exemplary electrodes operating in a mode having a first polarity (P1).

[0144] The exact shape of the electrode pattern depends in part on the shape of the expandable basket. This also means that the pattern and shape of the group of electrodes forming the virtual electrodes may differ in the collapsed configuration and / or different expanded configurations of the expandable basket. In most expanded configurations of the expandable basket, the rectangles and squares formed by the electrodes as described above are tilted, forming shapes that more closely resemble diamonds or rhomboids. The same applies to the angle between the two imaginary lines forming the cross and passing through the electrodes, which is not a right angle in most expanded configurations.

[0145] When using high-voltage pulses in the human body, it may be necessary for safety reasons to synchronize pulse delivery with the cardiac cycle, for example to avoid ventricular rhythm. Pulse field ablation devices may incorporate or use means for such synchronization, including triggering pulse delivery by this synchronization means. The synchronization means may be, for example, an ECG device.

Claims

1. 1. An ablation device for pulsed field ablation, comprising: a catheter including an outer elongate shaft having a proximal end, a distal end, and a lumen extending therebetween, and an inner elongate shaft having a proximal end and a distal end; an expandable basket having a proximal end, a proximal portion, a distal end, and a distal portion, the proximal end of the expandable basket secured adjacent the distal end of the outer elongate shaft and the distal end of the expandable basket secured adjacent the distal end of the inner elongate shaft, the expandable basket having a collapsed configuration and at least one expanded configuration; a set of electrodes formed on the expandable basket; a pulse generator electrically connected to the set of electrodes, the pulse generator being adapted to generate electrical pulses; Equipped with the expandable basket is formed from a braided mesh including a plurality of filaments, the filaments being made from a non-conductive material, at least some of the filaments including a lumen, the filaments further including an electrode and a plurality of conductive wires, at least one of the conductive wires being at least partially disposed inside the lumen of at least one of the filaments and electrically connected to at least one of the electrodes.

2. The device of claim 1 , wherein the device is a pulsed field ablation device.

3. The device of claim 1 , wherein the catheter is configured for pulsed field ablation.

4. The device of claim 2 , wherein the pulsed field ablation device is configured for use in the patient's heart.

5. The device of claim 4 , wherein the pulsed field ablation device is configured for pulmonary vein isolation.

6. The device of claim 1 , wherein the filaments are made from at least one of a thermoplastic elastomer or a polymer.

7. The device of claim 6 , wherein at least one of the filaments is reinforced by a mechanical support disposed in the lumen of the filament.

8. The device of claim 7 , wherein the mechanical support is a strut.

9. The device of claim 6 , wherein at least one of the filaments includes at least one location where the structure of the filament is locally mechanically weaker than the remainder of the filament.

10. The device of claim 9 , wherein the localized weaker areas form living hinges.

11. The device of claim 1 , wherein two or more of the filaments are merged with one another in at least one of the distal or proximal portions of the expandable basket to form at least one merged structure.

12. The merged structure of the at least one of the distal or proximal portions of the filament comprises: The device of claim 11 , comprising 1% to 30% of the total length of the filament.

13. The device of claim 11 , wherein at least one of the merged structures includes at least one location where the merged structure is locally mechanically weaker than the remainder of the merged structure.

14. The device of claim 13 , wherein the localized weaker areas form living hinges.

15. 1. A catheter for pulsed field ablation, comprising: an outer elongate shaft having a proximal end, a distal end, and a lumen extending therebetween; and an inner elongate shaft having a proximal end and a distal end; an expandable basket having a proximal end, a proximal portion, and a distal end and a distal portion, the proximal end of the expandable basket secured adjacent the distal end of the outer elongate shaft and the distal end of the expandable basket secured adjacent the distal end of the inner elongate shaft, the expandable basket having a collapsed configuration and at least one expanded configuration; a set of electrodes formed in an expandable basket; a pulse generator adapted to generate electrical pulses, said pulse generator electrically connected to said set of electrodes; a catheter, wherein the expandable basket is formed from a braided mesh including a plurality of filaments, the plurality of filaments being made from a non-conductive material, at least a portion of each filament of the plurality of filaments including a lumen, the plurality of filaments further including an electrode and a plurality of conductive wires, the plurality of conductive wires being at least partially disposed inside the lumens of the plurality of filaments and electrically connected to the electrode.

16. The catheter of claim 15 , wherein the catheter is configured for use in a patient's heart.

17. The catheter of claim 16, wherein the catheter is configured for pulmonary vein isolation.

18. The catheter of claim 15, wherein the catheter is configured to deliver radiofrequency electrical pulses.

19. The catheter of claim 15, wherein the plurality of filaments are made from at least one of a thermoplastic elastomer or a polymer.

20. 20. The catheter of claim 19, wherein at least one filament of the plurality of filaments is reinforced by a mechanical support disposed within the lumen of the filament.

21. The catheter of claim 20 , wherein the mechanical supports are struts.

22. 20. The catheter of claim 19, wherein at least one filament of the plurality of filaments includes at least one location where the structure of the filament is locally mechanically weaker than the remainder of the filament.

23. 23. The catheter of claim 22, wherein the localized weaker areas form living hinges.

24. Two or more filaments of the plurality of filaments are merged together in at least one of the distal or proximal portion of the expandable basket, and at least one The catheter of claim 15 , which forms a merging structure.

25. 25. The catheter of claim 24, wherein at least one of the merging structures of the at least one of the distal or proximal portions of the expandable basket comprises between 1% and 30% of the total length of the two or more filaments.

26. 25. The catheter of claim 24, wherein at least one of the merging structures includes at least one location where the merging structure is locally mechanically weaker than the remainder of the merging structure.

27. 27. The catheter of claim 26, wherein the localized weaker areas form living hinges.

28. 1. A method of ablation, comprising: a catheter including an outer elongate shaft having a proximal end, a distal end, and a lumen extending therebetween, and an inner elongate shaft having a proximal end and a distal end; an expandable basket having a proximal end, a proximal portion, a distal end, and a distal portion, wherein the proximal end of the expandable basket is secured adjacent to the distal end of the outer elongate shaft and the distal end of the expandable basket is secured adjacent to the distal end of the inner elongate shaft, the expandable basket having a collapsed configuration and at least one expanded configuration; and a set of electrodes formed on the expandable basket. providing a pulsed field ablation device comprising: a pulse generator adapted to generate electrical pulses, the pulse generator electrically connected to the set of electrodes, the expandable basket formed from a braided mesh including a plurality of filaments, the filaments made from a non-conductive material, at least a portion of each filament of the plurality of filaments including a lumen, the plurality of filaments further including an electrode and a plurality of conductive wires, the conductive wires being at least partially disposed inside the lumen of the plurality of filaments and electrically connected to the electrodes; delivering the catheter basket assembly adjacent to a treatment site; deploying the expandable basket from a collapsed configuration to at least one expanded configuration; positioning the basket assembly of the expanded expandable basket adjacent to target tissue at the treatment site; ablating the target tissue at the treatment site; A method comprising:

29. 29. The method of claim 28, wherein the treatment site is in the left atrium of the heart.

30. 30. The method of claim 29, wherein the treatment site comprises an ostium of a pulmonary vein.

31. 30. The method of claim 28, wherein the ablation of the target tissue at the treatment site uses a method of pulsed field ablation caused by a pulsed electromagnetic field.

32. 30. The method of claim 28, wherein at least a portion of the set of electrodes disposed on the basket assembly is adjacent the treatment site.

Images