Pulse electric field ablation device and method

Abstract

An ablation device and method for pulsed electric field ablation, the device comprising a catheter comprising an expandable basket, a set of electrodes formed on the expandable basket, and a pulse generator adapted to generate electrical pulses wherein the pulse generator is electrically connected with the set of electrodes. The expandable basket is formed from a woven mesh of filaments, where the filaments are made of a non-conductive material, where at least a portion of the filaments comprise an internal cavity, and where the internal cavity comprises a melted material, where the filaments further comprise an electrode and a wire. The wire is at least partially guided into the interior of the lumen of the filament and is electrically connected to the electrode.

Description

Technical Field

[0001] The present invention relates to ablation devices and methods, and more particularly to devices and methods for pulsed electric field ablation of target tissue by pulsed electric fields, wherein one of the main principles of ablation may be irreversible electroporation of cell membranes. Background Art

[0002] Atrial fibrillation is the most common persistent arrhythmia, affecting 10% of the population over 60 years old. In addition to drug treatment, so-called catheter ablation is an established therapy for improving disease symptoms and reducing mortality.

[0003] Catheter ablation involves advancing one or more flexible catheters subcutaneously into the patient's blood vessels, which are typically performed in the femoral vein, internal jugular vein, or subclavian vein during cardiac ablation. The catheter is then advanced towards the target treatment site within or on the heart.

[0004] The main methods of arrhythmia ablation treatment are to directly eliminate the arrhythmogenic substrate by destroying the arrhythmogenic substrate, or to prevent the propagation of non-physiological action potentials by linear or circular isolation. Both of these methods basically require the formation of lesions through which the action potential of the myocardium does not spread. By applying energy, a small portion of the myocardium is locally destroyed and transformed into non-myocardial connective tissue through natural physiological processes within a few weeks.

[0005] Common ablation methods known in the prior art are based on thermal destruction of tissue by high or low temperatures. Such methods include, for example, heating the target tissue by a radiofrequency field (RF) or laser, or freezing the tissue by cryoablation. These methods can cause necrosis of the target tissue, thereby increasing the surgical risk.

[0006] Recently, methods and devices for ablation using electric fields have been utilized. The goal of these methods is to cause tissue destruction by inducing irreversible electroporation of cell membranes rather than by high or low temperature destruction, thereby reducing the disadvantages and risks of ablation procedures mainly based on thermal damage. However, there are still disadvantages that need to be addressed.

[0007] A common design of such devices can be a catheter with a distal tip having one or more electrodes. The catheter can have, for example, an active electrode at the tip. Indifferent electrodes can be placed, for example, on the patient's skin. Ablation of the target treatment site with such a device must be performed point by point, which increases the duration and complexity of the surgery.

[0008] Another example of an existing device is a catheter with electrodes placed in a row at the distal tip of a single catheter body. The distal end of such a catheter is delivered close to the target treatment site and deployed (bent) into a specific shape near the target treatment site. Using this shape, treatment can be performed with more than one electrode and requires less distal movement, but it can be very difficult to deploy the catheter into the correct shape, position it correctly, and perform further operations using such a catheter. Irrelevant electrodes can also be placed on the patient's skin, or ablation can be performed in a bipolar manner between specific electrodes placed at the distal end of the catheter.

[0009] Devices with a catheter terminal basket are also known from the prior art, where the catheter terminal basket includes a single strut with electrodes. Such a device can ensure easier deployment and positioning relative to the target site. Since there are usually more electrodes placed on the catheter terminal, ablation can also be monopolar with, for example, an irrelevant electrode placed on the patient's skin, or bipolar between specific electrodes on the catheter terminal. One disadvantage of this solution is the limited number of struts, which means a limited number of electrodes can form a specific circular pattern in space. This disadvantage is due to the need for the mechanical stability of specific struts in order to be able to maintain the stable shape of the basket. This means that in order to be sufficiently rigid, the struts need to maintain a specific size. The number of struts used is limited by the catheter size. Another disadvantage of this solution is that this 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 either. This means that the device may need to be repositioned several times to ensure correct ablation, thus prolonging the duration of the procedure.

[0010] On the one hand, there is a need to improve the quality and safety of ablation procedures, and on the other hand, there is a need to reduce the risk to the patient and the treatment duration. Therefore, there is a need for improved ablation devices and methods that are gentler and safer for the patient, while reducing complexity and improving the quality and reliability of the method and the device itself. Summary of the Invention

[0011] Disclosed herein are a device and a method for an ablation system, in particular an ablation method and device for pulsed electric field ablation by an electric field according to the description, which can solve the above problems, are gentler and safer for the patient, reduce time and technical complexity, and improve the quality, efficacy, and reliability of the system, method, and device itself. Brief Description of the Drawings

[0012] An exemplary aspect of the present invention is illustrated by way of example in the drawings, in which like reference numerals represent like or similar elements, where:

[0013] Figure 1 Is a block diagram of an exemplary ablation system.

[0014] Figure 2 Overview of an exemplary pulsed electric field ablation device with a catheter.

[0015] Figure 3A An exemplary catheter with a shaft assembly is shown.

[0016] Figure 3B An exemplary illustration of a cross - section of the shaft assembly.

[0017] Figure 4 An exemplary illustration of the distal tip of the catheter, where the basket assembly is in an expanded configuration.

[0018] Figure 5 An exemplary distal tip of the catheter is shown, where the basket assembly is in a contracted configuration.

[0019] Figure 6A An exemplary expanded expandable basket is shown.

[0020] Figure 6B A detailed view of an exemplary expandable basket with filaments.

[0021] Figure 6C A detailed view of an exemplary expandable basket with filaments and wires.

[0022] Figure 7A A front view of an exemplary distal end of the catheter.

[0023] Figure 7B A side view of an exemplary distal end of the catheter.

[0024] Figure 8 An exemplary braided mesh with elongated electrodes is shown.

[0025] Figure 9 An exemplary braided mesh with filaments and wires located inside the lumen of the filaments is shown.

[0026] Figure 10 An exemplary schematic diagram of the position of the basket assembly adjacent to the treatment site.

[0027] Figure 11 A schematic diagram of an exemplary operating mode of the electrode.

[0028] Figure 12 A schematic diagram of another exemplary operating mode of the electrode.

[0029] Figure 13A An example of the spatial pattern of the electrodes on the distal tip of the catheter.

[0030] Figure 13B Another example of the spatial pattern of the electrodes on the distal tip of the catheter.

[0031] Figure 14Possible layout diagrams for electrodes that have been switched to the hybrid operation mode.

[0032] Figure 15A shows an exemplary pattern of the electrodes.

[0033] Figure 15B shows another exemplary pattern of the electrodes.

[0034] Figure 15C shows another exemplary pattern of the electrodes.

[0035] Figure 16 Shows a part of an exemplary pulsed electric field ablation protocol.

[0036] Figure 17a Shows an example of the pause between pulses where the voltage is different from 0V.

[0037] Figure 17b Shows examples of different biphasic pulses.

[0038] Figure 18 View of an example of a terminal assembly.

[0039] Figure 19 Shows another view of an exemplary terminal assembly.

[0040] Figure 20 Shows an example of filaments connected together at their intersections.

[0041] Figure 21 View of the distal part of a basket assembly with a merged structure and an active hinge.

[0042] Figure 22 Shows an example of filaments made by a molding process.

[0043] Figure 23 View of an example of a partially woven mesh including filaments made by a molding process.

[0044] Figure 24a Example of a planar woven mesh made by a molding process.

[0045] Figure 24b Shows a planar molded woven mesh bent into a tube.

[0046] Figure 24c Shows multiple planar molded meshes bent into tubes.

[0047] Figure 25a View of an example of a molded mesh molded into a three-dimensional structure.

[0048] Figure 25b View of an example of a molded expandable basket.

[0049] Figure 26Shows two filaments made by molding to produce a merged structure.

[0050] Figure 27 Shows an exemplary placement of components in a mold configured for injection molding of filaments.

[0051] Figure 28 Shows a cross-section of an expandable basket fixed to an internal elongated shaft.

[0052] Figure 29 Is a view of examples of the end of the internal elongated shaft and the expandable basket before and after mutual mechanical attachment.

[0053] Figure 30a Is a cross-sectional view of an expandable basket fixed to an internal elongated shaft.

[0054] Figure 30b Shows a detailed view of exemplary protrusions on an internal elongated shaft.

[0055] Figure 31a Shows a cross-section of a filament in a manufacturing step.

[0056] Figure 31b Shows a cross-section of a filament in another manufacturing step.

[0057] Figure 31c Shows another cross-section of a filament in another manufacturing step.

[0058] Figure 32 Is a block diagram of a pulse generator.

[0059] Figure 33 Is a schematic diagram of an improved half-bridge.

[0060] Figure 34 Shows the layout of electrodes imprinted in a two-dimensional plane. Detailed Description

[0061] Figure 1An ablation system (100) for pulsed electric field ablation of a target tissue is shown. The ablation system (100) described herein includes a pulsed electric field ablation device (101). The ablation system (100) may include or may be connected to other components or devices suitable for performing or supporting during the performance of the pulsed electric field ablation methods described herein. The other components 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 electrophysiology 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) may include a mapping device (135), such as, for example, a three-dimensional (3D) mapping device or a real position measurement (RPM) device, and / or an indifferent electrode (127). The mapping device (135) records, for example, an EGM (intracardiac electrogram) of positions in space measured via a catheter and forms a map of the cardiac surface. The position and orientation of the catheter may also be displayed. Other possible methods for measuring the true position of the catheter may be via sensors in the catheter (e.g., magnetically based position measurement) or, for example, using impedance measurement or radiofrequency-based measurement on the catheter electrodes or a combination thereof. Advantageously, in some examples, the catheter used for position measurement is the same as the catheter used for ablation.

[0062] The pulsed electric field ablation device (101) includes a pulse generator (103) for generating short high-voltage electric pulses and a catheter (105) suitable for insertion into a patient's body cavity, the distal tip (107) of the catheter being suitable for pulsed electric field ablation of a target tissue by a pulsed electric field of a set of electrodes (109). The catheter (105) is electrically connected to the pulse generator (103).

[0063] The generator (103) may be configured to generate high-voltage electric pulses, for example, at a frequency of 0.1 Hz to 10 Hz, with the amplitude of a single-phase pulse varying within 100 V to 5 kV and the peak-to-peak amplitude of a biphasic pulse varying within 200 V to 10 kV. The duration of the pulses may range from the nanosecond range to the millisecond range. An exemplary simplified schematic diagram of the generator (103) can be seen in Figure 32

[0064] The generator (103) may include a power supply unit (3200) that can generate an operating voltage, for example, from 100V to 5000V or from 250V to 2000V or from 500V to 1000V, at its output terminal. The power supply unit (3200) may also convert, for example, an alternating current from a current source (3202), such as from a plug, into a direct current at the output terminal of the power supply unit (3200). The power supply unit 3200 may have an output power from 100W to 5000W or from 200W to 3000W or from 500W to 1000W. The power supply unit 3200 may include a regulator 3201 that regulates the generation of the operating voltage. The operating voltage may be regulated based on feedback from the output of the power supply unit (3200), for example, turned on and off. The power supply unit (3200) may include a switched-mode power supply (3208), a safety transformer (3209) (such as a direct current to alternating current transformer), a power factor correction block (PFC) (3210), for example, the power factor correction block is configured to change the voltage from the current source (3202), for example, change the voltage from approximately 230V to approximately 400V; and / or at least one DC / DC converter (3211). The power supply unit (3200) may also be coupled to an electrical control circuit (115) and may be regulated, for example, turned on and off according to a signal from the electrical control circuit (115).

[0065] The output terminal of the power supply unit (3200) may be coupled to a capacitor unit (3203) including at least one capacitor (3212). The capacitor unit (3203) generates energy for high-voltage electrical pulses. The capacitance of the capacitor unit (3203) may be, for example, from 50μF to 1500μF, or from 80μF to 1000μF, or from 160μF to 750μF. The capacitor unit (3203) may include an emergency system (3207) that can cause the emergency dissipation of charge from the capacitor unit (3203) in the event of any failure in the pulsed electric field ablation device (101) or any measured parameter exceeding a safety boundary. The emergency system (3207) may include a safety discharge resistor configured to safely discharge the capacitor (3212), a thyristor protection, for example, configured to short-circuit the capacitor (3212) when necessary, and / or a contactor. The operating speed of the emergency system (3207) may be, for example, from 50ms to 100ms.

[0066] The generator may further include a switching unit (3204), which may include, for example, at least one switch (3205), such as a semiconductor switch. The input terminal of the switching unit (3204) may be coupled to the capacitor unit (3203), and the output terminal of the switching unit (3204) (i.e., the switch (3205)) may be coupled to at least one electrode (109) and may be configured to switch the electrode (109) to a first polarity mode, a second polarity mode, and a high impedance mode. The number of switches (3205) may depend on the number of independently switchable electrodes or groups of independently switchable electrodes (109). One switch (3205) may be coupled to one electrode (109) or more than one electrode.

[0067] The switch (3205) may be a semiconductor switch, such as an improved half-bridge (3300). A schematic diagram of the improved half-bridge (3300) can be seen in Figure 33 The improved half-bridge (3300) is an improvement over the traditional half-bridge. The improved half-bridge solves the parasitic characteristic problems of the traditional half-bridge, namely, the leakage current and output capacitance in the closed state. The improved half-bridge (3300) may include a top side and a bottom side. The top transistor (3301) is coupled with a common collector. The top resistor (3302) is coupled to the emitter of the top transistor (3301) with respect to the ground. Due to the position of the top resistor (3302), the voltage across the top resistor (3302) approaches zero in the closed state of the top transistor (3301). The improved half-bridge (3300) may further include a top diode (3303). The top diode (3303) is coupled to the emitter of the top transistor (3301) via its anode and to the output terminal (OUT) of the half-bridge (3300) via its cathode. In the case of the closed top transistor (3301) (high impedance state), the top diode (3303) can ensure that the current from the output terminal of the half-bridge (3300) does not pass through the top resistor (3302). The bottom transistor (3304) has a common emitter, and there is a bottom resistor (3305) coupled to the collector of the bottom transistor (3304). The bottom resistor (3305) is coupled to the positive power supply (+). Due to the bottom resistor (3305), the voltage across the bottom resistor (3305) approaches zero in the closed state of the bottom transistor (3304). The bottom diode (3306) is connected in reverse, that is, the anode of the bottom diode (3306) is coupled to the output terminal (OUT) of the improved half-bridge (3300), and the cathode is coupled to the collector of the bottom transistor (3304), preventing the output terminal (OUT) of the improved half-bridge (3300) from having a permanent output voltage.

[0068] In one example, when the switch unit (3204) is directly coupled to the capacitor unit (3203), the safety of the patient or the operator may depend on the reliability of at least one switch (3205). In the event of a failure of the switch (3205), the patient or the operator may be exposed to an uncontrolled dissipation of the high capacitance of the capacitor unit (3203) over a duration of 50 ms to 100 ms.

[0069] For example, to address such a risk to the patient or the operator, at least one DC / DC converter unit (3206) may be coupled between the capacitor unit (3203) and the switch unit (3204). The DC / DC converter unit (3206) may have an input voltage ranging from 100 V to 5000 V or from 250 V to 2000 V or from 500 V to 1000 V and an output voltage ranging from 150 V to 5000 V or from 500 V to 3000 V or from 1000 V to 2000 V. The DC / DC converter unit (3206) may include, for example, an output capacitor (3213) at its output.

[0070] The DC / DC converter unit (3206) may include an output capacitor emergency system (3214) that can cause an emergency dissipation of the capacitance from the output capacitor (3213) and cut off the voltage delivery from the generator (103) to the electrode (109) in the event of any failure in the pulsed electric field ablation device (101) or any measured parameter exceeding a safety boundary. The output capacitor emergency system (3214) may include a safety discharge resistor configured to safely discharge the output capacitor (3213), a thyristor protection and / or a contactor configured to short-circuit the output capacitor (3213) if necessary. The emergency dissipation of the capacitance from the output capacitor (3213) and the cut-off of the voltage delivery from the generator (103) to the electrode (109) may be shorter than 50 ms or 25 ms or 15 ms or 5 ms or 1 ms or 100 μs or 10 μs.

[0071] The capacitance of the output capacitor (3213) can be, for example, from 1 μF to 200 μF, or from 1.5 μF to 100 μF, or from 2 μF to 50 μF, or from 5 μF to 30 μF. The DC / DC converter unit (3206) can be, for example, a DC / DC converter without feedback. The DC / DC converter unit (3206) can be configured to convert the high capacitance of the capacitor unit (3203) to a lower capacitance at the output capacitor (3213). The DC / DC converter unit (3206) can also be configured for a rapid discharge of the capacitance of the output capacitor (3213). The DC / DC converter unit (3206) can, for example, also be configured to limit the leakage current from the power supply unit (3200) to the patient to a limit of, for example, below 10 μA. The leakage current can be generated, for example, by parasitic capacitance on the windings of the power supply unit (3200). The DC / DC converter unit (3206) can include two windings and can be, for example, a series resonant converter. The conversion ratio of the DC / DC converter unit (3206) can be, for example, from 1:1 to 1:6, or from 4:5 to 1:4, or from 2:3 to 1:3.

[0072] The power supply unit (3200), the capacitor unit (3203), the DC / DC converter unit (3206), the switch unit (3204) and / or the current source (3202) can be coupled to one or more electrical control circuits (115). The electrical control circuit (115) can, for example, receive data from the power supply unit (3200), the capacitor unit (3203), the DC / DC converter unit (3206), the switch unit (3204) and / or the current source (3202), and / or can send control signals to each of them. The data can include, for example, parameters measured at various locations of the pulsed electric field ablation device (101), the generator (103), the power supply unit (3200), the capacitor unit (3203), the DC / DC converter unit (3206), the switch unit (3204) and / or the current source (3202). The measured parameters can be, for example, temperature, impedance, current or voltage. The voltage can be measured, for example, at the output of the power supply unit (3200), the capacitor unit (3203), the DC / DC converter unit (3206), the current source (3202) and / or the switch unit (3204), for example, at the output of at least one switch (3205).

[0073] The electrical control circuit (115) can evaluate the received data and send control signals to the power supply unit (3200), capacitor unit (3203), DC / DC converter unit (3206), current source (3202), switch unit (3204), and / or other parts of the ablation device (101) based on the received data. In the case where at least one measured parameter exceeds a predetermined boundary, the electrical control circuit (115) can, for example, send control signals to the power supply unit (3200), capacitor unit (3203), DC / DC converter unit (3206), and switch unit (3204) to activate the safe disconnection of a specific unit or all units or a subset of units. The safe disconnection can mean, for example, cutting off the power supply unit (3200), activating the emergency system (3207) in the capacitor unit (3203) (discharging the capacitor (3212) to a safe discharge resistor and / or short-circuiting the capacitor (3212) via thyristor protection and / or contactors). In the DC / DC converter unit (3206), the safe disconnection can mean activating the output capacitor emergency system (3214) (discharging the output capacitor (3213) to a safe discharge resistor and / or short-circuiting the output capacitor (3213) via thyristor protection and / or contactors). The safe disconnection in the switch unit (3204) can mean disconnecting at least one switch (3205).

[0074] The pulsed electric field ablation device (101) can include or be connected to other components or devices suitable for performing or supporting during the performance of the pulsed electric field ablation method described herein. Other parts or devices can be, for example, a remote control unit (111), a graphical user interface (GUI) unit (113), an electrical control circuit (115), an electrocardiogram (ECG) device including an ECG trigger circuit (117), an ECG recording device (129), ECG electrodes (125), a pacing device (131), a catheter signal interconnection circuit (119), and / or an electrophysiology (EP) display device (133), which can include an EP recording system. The electrophysiology display device can display and / or record data from other devices connected to the ablation system (100). In addition, the ablation system (100) can include a mapping device (135), for example, a three-dimensional (3D) mapping device or a real position measurement (RPM) device, and / or indifferent electrodes (127). For example, the pulsed electric field ablation device (101) can be configured to be used in or on a patient's heart, for example, for the treatment of heart tissue, for example, for pulsed electric field ablation of heart tissue, for example, for pulsed electric field ablation of myocardial tissue, for example, for pulmonary vein isolation. The devices and methods disclosed herein can be used in other locations, for example, all tubular tissues, organs, or blood vessels in the body, or for example, tumor sites.

[0075] Figure 2The catheter (105) shown includes a shaft assembly (201) and a catheter distal tip (107) near the distal end of the catheter (105). The shaft assembly (201) defines a longitudinal central axis (203) of the catheter (105). The catheter (105) may also include a handle assembly (123) and a connection assembly (121). The catheter (105) may be steerable or non-steerable and may be introduced into its position, for example, via a guiding sheath (not shown) and with or without the aid of a wire (not shown).

[0076] The connection assembly (121) of the catheter (105) can be used for the interconnection of the catheter (105) with other components of the ablation system (100). The connection assembly (121) may include a single connection portion or multiple spatially separated connection portions. The connection assembly (121) may be located in the proximal portion of the catheter (105) and / or may be part of the handle assembly (123), for example. The connection assembly (121) portion may include, for example, one or more electrical connections, mechanical connections, fluid connections, and / or inputs for wires.

[0077] The connection assembly may include at least one connector, for example, an electrical connector, a fluid connector, a data connector, an optical connector, etc. The connector can be used for connecting and disconnecting the catheter (105) from other parts of the ablation system (100).

[0078] The handle assembly (123) can be mounted on the catheter shaft assembly (201) for, for example, steering and operating the catheter (105), and / or for precisely controlling the movement and deflection of the catheter (105). To allow the steering function, there may be a knob (not shown) connected to a steering wire (not shown), which can be connected near the distal portion of the catheter (105). The catheter is fed through a separate lumen and connected to the knob or steering mechanism (not shown) within the handle assembly (123). The handle assembly (123) may also include the connection assembly (121) or one or more connection portions of the connection assembly (121) and other components, for example, a handle (not shown) and / or a deployment mechanism (not shown) to deploy / retract the distal tip basket assembly (401, see Figure 4 ) and / or the expandable basket (409) by pushing / pulling the inner elongate shaft (301) and / or the outer elongate shaft (303) relative to each other. The deployment mechanism may include, for example, an actuator for actuating the inner elongate shaft 301 against the outer elongate shaft 303 in the longitudinal direction.

[0079] Figure 3A A catheter (105) having a shaft assembly (201) is shown. The shaft assembly may include an outer elongate shaft (303) and / or an inner elongate shaft (301). In Figure 3BThe cross-section of an exemplary shaft assembly (201) in the shown cross-section A-A may include two concentric tubes, with the outer tube being an outer elongate shaft (303) and the inner tube being an inner elongate shaft (301). The shafts may be translatable relative to each other in the longitudinal direction along a longitudinal central axis (203). Such translation may, for example, allow the expandable basket (409) to be deployed / retracted from a collapsed configuration to a fully expanded configuration and then returned.

[0080] The outer elongate shaft may include a proximal portion, a distal portion, and a body extending between the proximal and distal ends. The outer elongate shaft may be coupled to a handle assembly near its proximal portion and to a catheter distal tip near its distal portion.

[0081] The body of the outer elongate shaft (303) may include one or more lumens (309, 311), for example, extending along the entire length between its proximal and distal ends. The lumen may be adapted to guide a wire or a fluid, for example, a flushing fluid. One or more lumens may be configured to receive one or more inner elongate shafts. The body of the outer elongate shaft may be further defined, for example, by a proximal portion (305) and an intermediate portion (307). Compared with the proximal portion, the intermediate portion of the body may be designed with a flexible sheath to allow bending and increase the flexibility of the outer elongate shaft. The proximal portion includes, for example, a sheath of a harder material to increase the torque and stiffness of the body of the outer elongate shaft. Suitable materials for constructing the sheath include, but are not limited to, nylon, TPU, HDPE, or PEBA.

[0082] The body of the outer elongate shaft may include a wire. The wire may pass through the central lumen (309) of the outer elongate shaft, or the outer elongate shaft may include several other lumens (311), so that one or more wires may pass through one or more other lumens (311). For example, the number of other lumens may match the number of braided meshes on the catheter distal tip. For example, if 20 filaments are used in the construction of the catheter distal tip, 20 other lumens may be used.

[0083] The wire may extend from the basket assembly to a connection assembly, for example, near the handle assembly.

[0084] In some aspects, the inner elongate shaft may be configured to slide relative to the outer elongate shaft along the longitudinal central axis. Thus, one or more lumens may include, for example, a low-friction lining, such as a polytetrafluoroethylene (PTFE) lining.

[0085] Rigidity and torque are important characteristics that an external elongated shaft should possess. Thus, the external elongated shaft is laterally positioned above / around the PTEE lining. The external elongated shaft can include, for example, a braid of metal or rigid polymer wires wound around the inner layer of the body, which in some aspects is embedded within the outer sheath of the body, or can include a rigid polymer, including but not limited to polyimide, polyamide, polyetheretherketone (PEEK), or any other suitable material.

[0086] The outer layer of the external elongated shaft can contain a laminated polymer to provide a seamless, smooth, and soft surface. Note that, as previously mentioned, the outermost layers of the intermediate portion and the proximal portion can be formed of different polymers. For example, a nylon material can be used for the proximal portion, while a PEBA, which is softer compared to nylon for example, can be used for the outermost layer of the intermediate portion. However, these two portions can have the same innermost layer. The external elongated shaft can have a substantially constant outer diameter along its length.

[0087] The outer diameter (OD) dimension of the external elongated shaft can, for example, conform to the French catheter scale commonly used for catheter size standardization. The diameters in this scale are defined in Frenches (FR), where 1 mm = 3 FR. The scale typically ranges from a 3 FR catheter to a 34 FR catheter. For example, the diameter of the external elongated shaft can be between 5 FR and 20 FR, or from 7 FR to 16 FR, or from 9 FR to 15 FR. The diameter of the central lumen of the external elongated shaft can be approximately between 0.1 mm and 5 mm, or 1 mm to 4 mm, or 2 mm to 3.5 mm, or 2.5 mm to 3 mm.

[0088] The internal elongated shaft can include a proximal end, a distal end, and a body extending between the proximal and distal ends. The body of the internal elongated shaft can include one or more internal lumens (313), for example, extending along the entire length between the proximal and distal ends of the internal elongated shaft, or can be without internal lumens. One or more internal lumens (313) of the internal elongated shaft can be designed, for example, to accommodate standard wires (not shown) and / or to conduct fluids, such as irrigation fluid. The diameter of one or more internal lumens (313) can range from 0.1 mm to 3 mm, or from 0.5 mm to 1.5 mm, or from 0.9 mm to 1 mm, or from 0.94 mm to 0.99 mm. One or more internal elongated shafts can be adapted to be placed within one or more internal lumens (309, 311) of the external elongated shaft. The dimensions of the internal elongated shaft can be selected to match the diameter of the designated internal lumen of the external elongated shaft, but these two structures still need to allow for their smooth relative translation. This means that the outer dimensions of the internal elongated shaft (301) can range from 0.1 mm to 4.9 mm, or from 0.5 mm to 3.5 mm, or from 1 mm to 3 mm, or from 1.28 mm to 2.8 mm.

[0089] Because the inner elongated shaft may be adapted to receive a guide wire within its lumen, a low friction lining of the lumen may be used, such as a PTFE lining.

[0090] As described above, the inner elongated shaft can translate relative to the outer elongated shaft to deploy the basket assembly / expandable basket, so, for example, a braided socket can be braided along the length of the polytetrafluoroethylene liner to form the body of the inner elongated shaft. Another aspect can include a cut hypotube in the body of the inner elongated shaft instead of a braid to improve its flexibility and torque.

[0091] Laterally over the layer with the braid or hypotube, a polymer jacket may be melted / laminated to enhance the flexibility of the tube and provide a seamless surface. A variety of polymers may be used for the jacket, exemplary materials may be nylon, polyether block amide (PEBA), polyether ether ketone (PEEK), or polyimide.

[0092] Figure 4 The distal tip (107) of the illustrated example catheter further includes a basket assembly (401). The basket assembly (401) may 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 may include a central body portion (419) extending about a plane (425) that intersects the basket assembly in a portion having the highest diameter in the proximal and distal directions (in one of its expanded configurations), occupying approximately 1 / 3 of the basket assembly body. The basket assembly body may also 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 1 / 3 of the basket assembly body (407).

[0093] The basket assembly (401) includes an expandable basket (409). The basket assembly proximal portion (403) may include an attachment of the proximal portion of the expandable basket (409) adjacent the distal end of the outer elongated shaft (303). The distal portion of the basket assembly (401) may include an attachment of the distal portion of the expandable basket (409) adjacent the distal end of one or more inner elongated shafts (301), thereby forming a terminal assembly (411).

[0094] exist Figure 28Examples of attachment of the distal portion of an expandable basket (409) adjacent to the distal end of one or more internal elongate shafts (301) can be found. In this particular example, the distal end of the expandable basket (409) can be formed by means of a ring (2801) to which filaments (415) are fixed or around which the filaments (415) are bent at the location (2804) where the filaments (415) are fixed to the ring (2801). The distal portion of the expandable basket (409) is attached to the internal elongate shaft (301) by a mechanical locking mechanism. To lock the basket to the shaft, two protrusions (2802, 2803) are formed on the internal elongate shaft 301 such that the two protrusions hold either side (proximal and distal) of the basket distal end, for example including the ring 2801 that locks the expandable basket (409) to the internal elongate shaft 301. As Figure 29 shown, the assembly is formed by pushing the internal elongate shaft (301) with the first protrusion (2802) ready distally through an opening in the distal portion of the expandable basket, for example through a hole in the ring (2801), until the first protrusion (2802) on the shaft reaches the distal portion of the expandable basket from the proximal side. The internal elongate shaft end (2901) (the internal elongate shaft end protruding distally from the basket) is then tilted / heated on a bullet-shaped die to form a second protrusion (2803) with an anti-damage bullet-shaped end, which will prevent the internal elongate shaft (301) from moving proximally relative to the expandable basket (409). This connection is made in such a way that it locks the internal elongate shaft (301) to the expandable basket (409) under operating conditions, but also in such a way that in the case where the basket cannot be deployed and the catheter needs to be withdrawn from the patient's body, the connection will break and become loose under a certain axial load. The axial load (force) required to break the connection can be from 10 N to 100 N, or from 15 N to 75 N, or from 20 N to 50 N.

[0095] The protrusions (2802, 2803) can also be formed on the internal elongate shaft by other techniques. Figure 30a and Figure 30bA specific example is shown. In this example, the second protrusion (2803) may be formed by a distal attachment member (3001) coupled to the inner elongate shaft (301) (e.g., coupled to the distal end of the inner elongate shaft (2901)). The distal attachment member (3001) may have the form of, for example, an annular, cylindrical, conical, frustoconical, or hollow tubular body, e.g., having a trauma-preventing shape formed at its distal end (e.g., bullet-shaped, flanged), e.g., to ensure that the terminal assembly does not mechanically injure the patient, and may be made of, for example, plastic or metal. The distal attachment member 3001 may include a tubular structure (3002) protruding proximally from the second protrusion 2803 parallel to the inner elongate shaft. The distal attachment member (3001) and / or the tubular structure (3002) may include a cavity (3006), e.g., the cavity being adapted to receive at least a portion of the inner elongate shaft (301), e.g., the distal end of the inner elongate shaft (2901) and the wire. The cavity (3006) may have two inner diameters, a first diameter (3007) formed proximally of the distal attachment member (3001) and large enough to fit at least a portion of the inner elongate shaft (301), e.g., the distal end of the inner elongate shaft (2901), and a second diameter (3008) formed distally from the first diameter (3007) and smaller than the first diameter (3007) and smaller than the outer diameter of the inner elongate shaft (301), e.g., the inner elongate shaft being configured for the wire to pass through. With this configuration of the cavity (3006), the distal attachment member (3001) can serve as a distal stop for the inner elongate shaft (301) in the direction of the longitudinal central axis (203), while also preventing possible sharp edges of the distal end of the inner elongate shaft (2901) from being exposed distally of the distal attachment member (3001) and preventing tissue damage that may be caused upon contact. The distal attachment member 3001 may be coupled to the inner elongate shaft 301, and the coupling may include, for example, crimping, welding, screws, threads, molten plastic, or an adhesive, e.g., a hot melt adhesive or glue.

[0096] In Figure 30a and Figure 30bIn the specific example shown, the distal attachment member (3001) can be coupled to the inner elongate shaft (301) by, for example, molten plastic or an adhesive. The distal attachment member 3001 can include a cavity having a diameter larger than the outer diameter of the inner elongate shaft 301, for example, 0.1% to 50% or 0.5% to 40% or 1% to 25% larger. The inner elongate shaft can be inserted into the cavity, and the space (3003) created between the inner elongate shaft (301) and the cavity wall can be filled with an adhesive, for example, a hot melt adhesive or glue. For this purpose, the distal attachment member 3001 can include a glue opening 3004, which can serve as an entrance for the adhesive to enter the created space 3003. After filling the glue into the created space (3003), the glue opening (3004) can be closed and sealed, for example, by a plug, molten plastic, or by an adhesive, for example, by a hot melt adhesive or by glue, possibly the same adhesive used to couple the distal attachment member (3001) to the inner elongate shaft (301).

[0097] As Figure 30a and Figure 30b shown in the example of, the first protrusion (2802) can be formed, for example, by a tubular proximal attachment member (3005) coupled to the inner elongate shaft (301). The proximal attachment member (3005) can be directly coupled to the inner elongate shaft (301), or can be coupled to the inner elongate shaft (301) via, for example, the distal attachment member (3001), for example, to a tubular structure (3002). In Figure 30a and Figure 30b shown in another example, the proximal attachment member 3005 can be directly and indirectly coupled to the inner elongate shaft 301 via the distal attachment member 3001. The coupling of the proximal attachment member (3005) to the inner elongate shaft (301) and / or the distal attachment member (3001) can include, for example, crimping, welding, screws, threads, molten plastic, an adhesive (e.g., a hot melt adhesive or glue), or another fixing member (not shown) placed proximal to the inner elongate shaft (301). The first protrusion (2802) can have a form or can include, for example, a plastic tube.

[0098] The ring (2801) to which the filament (415) is fixed can be directly coupled to the inner elongate shaft (301), or can be coupled to the inner elongate shaft via, for example, the distal attachment member (3001) or the proximal attachment member (3005). Figure 30a and Figure 30b show an example of a ring 2801 coupled to the inner elongate shaft 301 via the distal attachment member 3001. In this specific example, the distal attachment member 3001 includes a tubular structure 3002 that protrudes proximally from a second protrusion 2803 parallel to the inner elongate shaft, and the ring 2801 can surround the tubular structure 3002.

[0099] The terminal assembly (411) can advantageously be designed to have no or at least a reduced structure protruding in the distal direction from the distal portion (405) of the basket assembly, for example, a cap or similar structure. This is particularly advantageous when at least part of the ablation method needs to be performed on a relatively flat treatment site.

[0100] An exemplary solution for the terminal assembly can be an overmolded structure. The filaments can be fixed to each other and / or to the distal end of the inner elongate shaft by an overmolding process to form an overmolded terminal assembly. Another fixing process (and / or terminal assembly forming process) similar to overmolding can be, for example, tipping, where the filaments are at least partially melted and pressed into a preformed mold so as to be joined together and / or joined to the inner elongate shaft. Laminating is another exemplary process for fixing the filaments at their distal ends to form a terminal assembly. The terminal assembly can also be formed 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 by, for example, a metal ring.

[0101] In another example, the terminal assembly can be formed as Figure 18The articulated mechanical structure shown. For example, one or more filaments can be located at their distal ends in the terminal assembly area fixed to the articulated element (1801), and these articulated elements include, for example, a transverse narrow portion (1803) and a distal portion (1805) wider than the transverse narrow portion (1803). The transverse narrow portion (1803) can be in the form of a pin with a square, rectangular, circular, elliptical or other suitable cross-section. The distal portion (1805) can have, for example, an elliptical or circular form, or in another example, a spherical or spherical shape. Other possible shapes of the distal portion (1805) can be cylindrical, conical, cubic or block-shaped. For example, in the case where the entire articulated element (1801) is made of a piece of sheet material (metal plate, polymer plate) or is not made of a piece of sheet material (for example, in the case of a cast or forged articulated element), it can have a size that is the same as the transverse narrow portion (1803). The articulation element 1801 can be made, for example, of a metal (e.g., nitinol) or other material (e.g., a polymer or thermoplastic). The fixation of the filament to the articulation element can be accomplished, for example, by welding, gluing, or crimping. The area of ​​the connection (1807) can, for example, be at least partially laminated to prevent possible tissue damage and seal the assembly. The articulation element is then fixed in a central bullet structure (1809). This can be, for example, a hollow structure with a cutting window (1811) suitable for accommodating the proximal portion (1803) of the articulation element (1801). In this case, the distal portion (1805) of the articulation element is placed in an inner cavity (1813) inside the hollow structure. In some examples, the size (cross-section or width) of the distal portion (1805) of the articulation element can be larger than the size of the window (1811). This prevents the distal portion (1805) of the articulated element (1801) from sliding through the window (1811), thereby retaining the articulated element and, together with them, the connection region (1807) and the distal portion of the filament attached to the central bullet structure (1809). The central bullet structure (1809) may include several parts connected together (e.g., by welding, gluing or other mechanical means, such as snaps, threads, screws, bolts...). It may also have different shapes, such as cylindrical, spherical or elliptical. The shape of the inner cavity (1813) may correspond to the outer shape or may be different. The central bullet structure may include a fixing member (1815) for fixing the distal end of the inner elongated shaft to the central bullet structure. The fixing member (1815) may have, for example, the shape of a hollow tube connected to the central bullet structure. The fixing member is suitable for accommodating and / or connecting the distal portion of the inner elongated shaft and may allow the flow and / or redirection of a fluid, such as a flushing fluid flowing out of the lumen of the inner elongated shaft. The fixing member may interfere with the lumen (1813) or may be mechanically and / or fluidically connected to the lumen. Figure 19The aperture (1901) shown introduces at least a portion of the flushing fluid into the lumen of the central bullet structure.

[0102] Such a hinge mechanism as described above can allow the filaments to move more easily radially (with respect to the longitudinal central axis of the catheter) in the terminal assembly region, which is advantageous during the operation of the expandable basket, especially during the transition (expansion / retraction) between the collapsed configuration and one or more expanded configurations.

[0103] In the case of using metal components in the design of the terminal assembly, for example, the metal components can be used as electrodes for ablation or sensing or mapping or a combination thereof.

[0104] The expandable basket can be connected to the inner elongate shaft and / or the outer elongate shaft by gluing, welding, laminating or mechanically.

[0105] For example, the expandable basket (409) can be Figure 5 transferred (expanded / retracted) between the collapsed configuration shown and one or more expanded configurations. The transfer (expansion / retraction) can be caused by the pre-stretched shape of the braided mesh (413) and / or the filaments (415) and / or by the linear displacement of the inner elongate shaft (301) along the longitudinal central axis (203) of the catheter (105) against the outer elongate shaft (303) or a combination thereof. Another possibility for expanding / retracting the expandable basket (409) can be by the tension of an additional support structure, such as an inner coil or a balloon (not shown).

[0106] The expandable basket can include filaments woven into a braided mesh or a molded mesh. In the collapsed configuration, the cross-section of the expandable basket can be equal to or dimensionally close to the cross-section of the outer elongate shaft, although in one aspect, the cross-section of the expandable basket can be smaller than the cross-section of the outer elongate shaft and can depend on the size 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, from 20 mm to 40 mm or from 22 mm to 38 mm or from 25 mm to 35 mm. Such a size of the fully expanded expandable basket can be suitable for placement in a heart cavity, for example. For larger body cavities, the expandable basket can have a larger size, for example, from 30 mm to 150 mm, or from 40 mm to 120 mm, or from 50 mm to 100 mm. In other cases, a fully expanded expandable basket with a smaller size can be suitable for smaller body cavities. Such a smaller expandable basket can have a size of, for example, from 3 mm to 25 mm, or from 5 mm to 15 mm, or from 7 mm to 10 mm in its fully expanded state.

[0107] In some aspects, the filaments (415) woven into the woven mesh (413) are not cut near the distal portion of the expandable basket (409), but the filaments (415) can be bent at the distal portion and connected near the distal portion of the inner elongate shaft to form a terminal assembly. The bent filaments can then be routed back to the expandable basket (409) or the outer elongate shaft, where the filaments can terminate. Figure 6A The expandable basket (409) with bent filaments at its distal portion (603) is shown in more detail.

[0108] The expandable basket made of a woven mesh is superior to prior art solutions with non-woven struts because the expandable basket has higher mechanical stability, even when using relatively thin filaments. More filaments in the structure can also allow for the use of more electrodes. Electrodes placed on the filaments can also be distributed more optimally, which means that, for example, the electrodes can be placed closer together or a desired pattern can be created on the expandable basket. Another advantage of the expandable basket made of a woven mesh is that the structure has higher mechanical stability, which can ensure a stable and predictable distance between the electrodes.

[0109] The woven mesh can be heat-treated, which can ensure filament deformation and fixation of this deformation. Then, these deformed filaments ensure that during expansion and contraction of the basket assembly (expandable basket), the crossing points of the filaments (the points where the filaments intersect each other) remain relatively stable in terms of filament length. This means that in the contracted state and all expanded states of the basket assembly (expandable basket), the filament crossing points remain at a relatively the same filament length distance. The mutual angle of the specific filaments creating the crossing points (e.g., from about 2 degrees to 178 degrees and vice versa) changes. This process may not completely avoid some minor longitudinal movement of the crossing points, but this movement remains within limits that do not compromise the size and / or mechanical stability of the woven mesh. This feature can then, for example, allow electrodes to be placed at the crossing points of the filaments and / or ensure a stable, predictable and desired mutual position and / or their mutual distance of the electrodes.

[0110] Further structural stability of the expandable basket made of a woven mesh can be achieved by connecting specific filaments (including those in the woven mesh) together. The filaments can be connected together, for example, at their mutual crossing points. An exemplary solution can be as Figure 20 shown. The joint (2001) can be fixed (not allowing any mutual movement of the filaments at the connection point) or interactive (some mutual movement of the filaments at the connection point is possible). This connection can be achieved, for example, by gluing, welding, laminating, bonding, tying (e.g., with some string) or melting. Another option can be, for example, to tie the filaments together by means of a loop structure or crimping. In the case where the loop structure is made of a conductive material (e.g., metal), it can also be used as an electrode. The same applies to crimping. Metal connectors can also be used as electrodes.

[0111] Even before braiding, a structure suitable for connecting two filaments may already be included on the filaments. In an example where at least one filament (415) is made by a molding process (e.g., an injection molding process), the filament (415) may include at least one region that divides the filament and / or at least one region that will create additional loops (2201) on the filament during the molding process, as Figure 22 and Figure 23 visible in. Such at least one dividing region and / or additional loop (2201) may be formed, for example, at or near at least one filament intersection region (2202), which is the region where the filament intersects with another filament at the intersection (2301) in the braided grid. A slit or loop (2201) on the first filament (415) included in the intersection (2301) may be adapted to insert into the second filament (415) included in the intersection (2301), thereby helping to connect (fix) the two filaments (415) together at the intersection (2301). Such an intersection (2301) where the filament (415) is fixed by the loop (2201) or slit may have properties similar to an intersection connected, for example, by tying a knot with a rope, but does not require a knotting step.

[0112] In one example, when the first filament included in the intersection includes a loop at and / or near the intersection region participating in the intersection, the second filament included in the intersection does not include a loop at and / or near the intersection region participating in the specific intersection, which means that there can be at most one loop in any intersection. The length of the loop (from the first connection point with the filament to the second connection point with the filament) at and / or near the intersection region on the first filament in the intersection may be selected according to the diameter of the second filament included in the intersection (the other filament must fit into the loop, but the loop should not be too loose around the other filament), and may be, for example, from 0.5 mm to 10 mm, or from 1 mm to 7 mm, or from 2 mm to 5 mm. The cross-sectional diameter of the loop may be, for example, from 0.1 mm to 1 mm, or from 0.15 mm to 0.7 mm, or from 0.2 mm to 0.5 mm.

[0113] All intersections included in the expandable basket may be connected, or only some intersections may be connected while the remaining intersections may not be connected.

[0114] In another example, the expandable basket may be made by a molding process, e.g., by an injection molding process. In this example, the mesh of the expandable basket may not be braided, but may be made of a molded structure. There may be several options for how to manufacture the expandable basket by molding.

[0115] The expandable basket can be made, for example, of at least one molded web (flat, planar molded web) (2401) in the form of a two-dimensional (flat, planar) structure, as Figure 24a shown. The at least one planar molded web (2401) is configured to be formed into a three-dimensional shape after molding. The at least one planar molded web can be removed from the mold after molding and can be bent, for example, around a central longitudinal axis (203), for example, bent into a tube as Figure 24b shown. Figure 24c is an example where more than one planar molded web is used to form the expandable basket. In this example, each molded web (2401) can be bent into a shape that independently forms only a part (circumferential part of the intended tube) of the intended tube, and when combined together, forms the entire tube. Then, the edges (2402) of the molded webs will be coupled together (e.g., by welding, crimping, gluing, knotting...), to form a tubular structure. Thereafter, the distal parts (2403) of the tubular structure can be brought together and coupled together, and may be fixed to the distal part of the internal elongate shaft, thus forming a terminal assembly, and thus forming the expandable basket. The proximal part (2404) of the tubular structure can be coupled to the distal end of the external elongate shaft.

[0116] In another example, the expandable basket can be made of a molded web that has been molded into a three-dimensional structure. Figure 25a shows an example of such a structure, which can be, for example, a tubular molded web structure (2501). In this example, the step of bending the two-dimensional planar molded web can be omitted, and the tubular molded web structure has already been made in the mold. Further steps will be similar to the previous example. The distal parts (2403) of the tubular molded web structure (2501) can be brought together and coupled together, and may be fixed to the distal part of the internal elongate shaft, thus forming a terminal assembly, and thus forming the expandable basket. The proximal part (2404) of the tubular molded web structure (2501) can be coupled to the distal end of the external elongate shaft.

[0117] In Figure 25b another example shown, the expandable basket (409) can be molded in a single step. In this particular example, the expandable basket is made directly by a molding process, where the distal parts (2502) of the expandable basket have been molded together, thus forming at least a part of the terminal assembly in a single step, while molding the rest of the expandable basket. Then, the molded distal part (2502) of the expandable basket (409) can be coupled to the distal end of the internal elongate shaft, and the proximal part (2503) can be coupled to the distal end of the external elongate shaft.

[0118] The molded web molded into a three-dimensional structure can have a shape other than tubular. For example, it can be molded into the shape of an expandable basket in an expanded state.

[0119] A molded mesh molded into a three-dimensional structure need not be molded into the entire structure, but rather several three-dimensional portions of the molded mesh may be molded and then coupled together. For example, the three-dimensional components may independently form only a part of the intended structure (e.g., a part of the circumference of a tube or basket in one of its expanded states), and when brought together and joined form the entire structure.

[0120] In an example of an expandable basket made of a molded mesh, electrodes, wires, and / or other structures (e.g., tubes for forming a lumen, reinforcing struts, etc.) may be placed in the mold prior to molding and may be overmolded during the molding of the molded mesh. These structures may be fully overmolded, which means these structures will be entirely within the molded mesh and not reach the surface of the molded mesh, and / or partially, e.g., when at least a portion of the surface of these structures is exposed on the surface of the molded mesh. For example, an electrode may be partially overmolded when at least a portion of its surface is exposed on the surface of the molded mesh. However, these structures need not be overmolded, and at least a portion of these structures may be added to the molded mesh after the molding process of the molded mesh.

[0121] The molded mesh may be made of a polymer or a thermoplastic elastomer, such as, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or, for example, silicone.

[0122] The specific openings (meshes, gaps) within the woven or molded mesh need not have uniform dimensions. Instead, the dimensions of the specific openings may vary. The dimensions may, for example, increase in the direction from the distal and proximal portions of the expandable basket (where the dimensions may be the smallest) towards the middle portion of the expandable basket (where the dimensions may be the largest). In other words, the dimensions of the openings in the central body portion of the basket assembly may be larger than the dimensions of the openings in the proximal and distal body portions of the basket assembly. The dimensions may, for example, increase linearly or exponentially. The perimeter of the openings in the proximal and distal body portions may be, for example, between 1 mm and 40 mm, while the perimeter of the openings in the central body portion may be, for example, between 5 mm and 80 mm. The number of rows of openings forming the complete woven or molded mesh of the expandable basket may be between 4 and 40.

[0123] The ratio of the perimeter of the smallest opening to the perimeter of the largest opening in the expandable basket can be from 100:101 to 1:80, or from 20:21 to 1:50, or from 10:11 to 1:40. The number of rows of openings can be counted starting from the first complete opening, which starts from the connection where the proximal part of the expandable basket is adjacent to the distal end of the external elongated shaft, until the last opening terminated by the terminal assembly in the distal part of the basket assembly. The total number of openings included in the woven or molded mesh forming the expandable basket (the total number of openings in the expandable basket) can be from 12 to 1000, or from 16 to 500, or from 24 to 259, or from 32 to 128.

[0124] Two or more filaments forming the woven or molded mesh and thus forming 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 parts of the expandable basket, as Figure 21 Schematically shown. This solution can reduce the number of filaments in the proximal and / or distal parts of the expandable basket. Reducing the number of filaments entering the relevant structures (e.g., the proximal part of the basket assembly and / or the distal part of the basket assembly) can reduce the complexity of these structures (and thus the entire basket assembly) and / or enhance the mechanical stability of these structures. The proximal part of the basket assembly can include an attachment of the proximal part of the expandable basket adjacent to the distal end of the external elongated shaft, and the distal part of the basket assembly can include a terminal assembly. Due to the reduction in the number of components in the structure with a reduced number of filaments, this even helps to reduce the risk of the ablation process. In terms of the filament length, the merged structure in the proximal or distal part of the filament can occupy 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 before, the filaments can be merged at the distal or proximal end of the filament or at both of these positions. In the case where the filaments are merged at both ends, the merged lengths can be the same or different at both ends. Relative to the length of the expandable basket in the contracted configuration, at the proximal or distal end of the basket, the merged part of the filaments can occupy 1% to 35% or 4% to 25% or 6% to 20% of the length of the contracted basket. The filaments can be merged, for example, by gluing, welding, laminating, bonding, bundling, or melting. Another option can be, for example, to connect the filaments together by means of a certain tubular structure or by crimping. The tubular structure can be, for example, a tube with an inner cavity made of metal, polymer, or thermoplastic. In this case, the ends of the filaments will pass through the inner cavity of the tube and be fixed there (e.g., by gluing, welding, laminating, bonding, bundling, melting, or swaging) and thus joined together. Another option can be to use a multi - cavity tube made of metal, polymer, or thermoplastic, where each end of each filament to be joined will pass through a separate (its own) cavity of the multi - cavity tube and be fixed there (e.g., by gluing, welding, laminating, bonding, bundling, melting, or swaging) and thus joined together.

[0125] In an example with filaments (415) made by a molding process (e.g., injection molding), at least two filaments (415) can be molded into a single filament, woven into a woven mesh, and then joined together at their proximal and / or distal ends to form a joined structure (2101). However, at least two filaments (415) can be molded at once such that at least one joined structure (2101) (proximal or distal) can already be formed during the molding process. In Figure 26 Examples of filaments (415) and joined structures (2101) made by a molding process can be seen. Then, the filaments (415) including the already molded joined structure (2101) can be woven into a woven mesh, and at least one step of joining the filaments after weaving can be avoided. After the weaving process, the ends of the filaments (415) that were not joined during the molding process can be joined together and / or joined with other different filaments.

[0126] The filaments can be made of an electrically insulating, non-conductive material such as a polymer or a thermoplastic elastomer such as nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or for example, silicone. The material can be further reinforced, for example, by glass fibers. The cross-section of the filaments can be circular, or other cross-sectional shapes are possible, such as but not limited to oval, round, semi-circular, rectangular, square, flat, or star-shaped. The filaments (415) can be formed, for example, by a tube having at least a partially hollow structure with an inner lumen (601), as Figure 6B shown. Some or all of the filaments (415) can be hollow along their entire length, or for example, the inner lumen (601) can only be present in a portion of the length of one or more filaments (415). On the other hand, a woven mesh (413) can be included that includes a first subset of filaments (415) having an inner lumen (601) and another subset of filaments (415) without an inner lumen, or all filaments have no inner lumen.

[0127] In another example, the filaments can be made by a molding process, for example, by an injection molding process. Electrodes (109), for example, wires (417) connected to the electrodes (109), and / or other components (e.g., tubes for forming the inner lumen, reinforcing struts (2702), other wires, etc.) can have been placed in the mold (2701) before molding and can be in as Figure 27Overmolding during the molding of the filaments shown. Components can be fully overmolded, which means that these components will be entirely inside the molded filaments and will not reach the surface of the filaments (will not be exposed on the surface of the filaments), and / or partially, for example when at least a part of the surface of these components is exposed on the surface of the filaments. For example, an electrode can be partially overmolded when at least a part of its surface is exposed on the surface of the molded filaments. However, these structures do not have to be overmolded, and at least a part of these structures can be added to the filaments after the molding process of the filaments, and thus added to the later woven mesh.

[0128] Filaments made of an electrically insulating tube with a hollow structure (cavity) may have drawbacks. For example, when an electrode (e.g., in the form of a tube) is placed on the filament and the wire coupled to the electrode is guided inside the inner cavity of the filament. A small opening in the filament wall is typically used for the transition of the wire through the filament wall. This small opening needs to be sealed to prevent, for example, blood or other liquids from reaching the inside of the filament. In the case where the electrode is an annular electrode placed around the filament, a seal can be made between the filament and the electrode. Typically, such a seal is achieved by placing glue in the area between the edge of the electrode and the filament on which the electrode is placed. The glue ensures the seal between the electrode and the filament. Another advantage of this solution is that the glue on the edge of the electrode increases the hardness of the filament in the immediate vicinity of the electrode, which ensures that in the case where the filament needs to be bent in the area where the electrode is placed, the bending of the filament occurs away from the edge of the electrode, preventing the exposure of the edge of the electrode. The electrode may have sharp edges, and the exposure of such sharp edges may, for example, cause harm to the patient. The drawback of the solution of placing an annular electrode on a tubular filament and sealing it with glue is that the seal adds additional material, which means that the diameter of the filament increases at the place where the glue is applied on the filament, which is a problem for catheters with a large number of filaments. Another problem with the solution of applying glue to seal the electrode to the filament is that the glue may peel off, which may cause a part of the glue to become loose and may harm the patient. These problems can be solved by, for example, filaments made by a molding process or filaments in another example.

[0129] In another example, the filament (415) can take the form of at least a partially hollow structure, for example, including a tube made of a non-conductive material (e.g., thermoplastic). An exemplary cross-section of such a filament (415) can be at Figures 31a to 31cAs seen in. The filament (415) including the electrode (109) (e.g., a toroidal electrode) may include at least two tubes (3100), and the two tubes may be coupled to each other at the position where the electrode (109) is placed on the filament (415). The tubes (3100) may be made of a material having a melting point, e.g., a material having a melting point lower than that of other structures in the filament, e.g., a thermoplastic. The coupling of the tubes may include a molten material (3101), which may come from, for example, at least one of the tubes (3100). The molten material (3101) may fill the inner cavity of the electrode (109) and seal the electrode and / or the wire (417) coupled to the electrode, or another structure leading from the inner cavity of the filament to the electrode (109), or any other structure leading to the inner cavity of the filament, and may ensure the connection of the tubes to each other. The filament may include a wire (3102), which may be longitudinally placed inside the inner cavity of the filament and may be continuously guided at least in the region where the electrode (109) is placed on the filament (415). Thus, in this region, the tubes (3100) are coupled to each other. The wire (3102) may be used as a reinforcement for the filament.

[0130] The manufacturing process of the filament including at least two tubes described in the previous paragraph may include Figures 31a to 31c the steps shown. In the first step, as Figure 31a shown, the tubes (3100) and the electrode (109) are placed on the wire (3102) such that the electrode (109) is placed between the tubes, thereby forming an assembly. The wire (417) coupled to the electrode (109) leads into the inner cavity of one of the tubes (3100). In the next step, the entire assembly is heated to at least the melting temperature of the material of which the tubes (3100) are made. The tubes (3100) melt, and the molten material from the ends of the tubes adjacent to the electrode flows into and fills the inner cavity of the electrode. In the next step, the assembly is cooled to a temperature at least lower than the melting temperature of the material of which the tubes (3100) are made. The result of this step can be seen in Figure 31b and / or Figure 31c as seen.

[0131] Figures 31a to 31cThe exemplary filament (415) shown may include other structures, in particular at least one loop (3103). The loop may be made of a material different from that of the tube (3100). In particular, the melting point of the material of the loop (3103) may be higher than the melting point of the material of the tube (3100), and the flexure point of the material of the loop (3103) may be approximately the same as the melting point of the material of the tube (3100). The loop may be positioned on the tube, in particular on the tube end adjacent to the electrode (109). The loop may serve as an additional sealing element, surface smoothing element, and reinforcement element in the transition between the edge of the electrode (107) and the tube (3001). The loop may prevent the material of the tube from overflowing the electrode during the manufacturing process. The loop also contributes to the bending point of the filament. In the case of filament bending, this helps to move the bending point away from the electrode at the sharpest angle, which is beneficial for example in preventing the sharp edges of the electrode from being exposed. The length L of the loop may be from 0.1 mm to 10 mm or from 0.2 mm to 5 mm or from 0.5 mm to 4 mm or from 0.7 mm to 2.5 mm. The filament may include one loop adjacent to one side of the electrode, or may include at least two loops, for example adjacent to both sides of the electrode.

[0132] The inner diameter of the loop (3103) before the manufacturing process may be equal to or greater than the outer diameter of the tube (3100) before the manufacturing process. In the first step of the manufacturing process, the loop (3103) may be placed on the tube (3100), in particular on the tube end adjacent to the electrode (109), as Figure 31a shown, and the tube (3100) with the electrode (109) may be placed on the wire (3102) such that the electrode (109) is placed between the tubes (3100) with the loop (3103), thereby forming an assembly. In the next step, the entire assembly is heated to at least the melting temperature of the material of the tube (3100) and the flexure temperature of the material of the loop (3103). When the loop (3103) shrinks, the tube (3100) melts, and the molten material from the tube end adjacent to the electrode flows into the inner cavity of the electrode and fills it. The softened loop (3103) should shrink until its outer diameter reaches the same size as the outer diameter of the electrode (109), or between the same size as the outer diameter of the electrode (109) and the outer diameter of the electrode (109) minus 10%, or between the outer diameter of the electrode (109) minus 0.1% and the outer diameter of the electrode (109) minus 7%, or between the outer diameter of the electrode (109) minus 0.2% and the outer diameter of the electrode (109) minus 5%. This amount of shrinkage can prevent the material of the loop (3103) from melting on the electrode in the next step, which may lead to potential insulation problems or the peeling of this molten material on the electrode during use. The result of this step can be seen in Figure 31b In the next step, the assembly is further heated to the melting temperature of the material of the loop (3103). As Figure 31cAs shown, the material of the ring (3103) melts and bonds itself to the material of the tube (3100). In the next step, the assembly is cooled at least at the melting temperature of the material of which the tube (3100) is made.

[0133] Due to the shrinkage of the molten material of the tube (3100) and due to some of the material of the tube filling the inner cavity of the electrode during the manufacturing process, the outer diameter of the tube (3100) may be higher than the outer diameter of the electrode before the manufacturing process. This outer diameter can be, for example, 1% to 60% higher, or 3% to 50% higher, or 5% to 40% higher, or 10% to 35% higher. The materials of the tube (3100) and the ring (3103) can be, for example, thermoplastics with two different melting temperatures, such as, for example, nylon. The materials can be selected such that the melting point of the material of the ring (3103) can be higher than the melting point of the material of the tube (3100), and the flexure point of the material of the ring (3103) can be approximately the same as the melting point of the material of the tube (3100).

[0134] The diameter of the filaments of the braided or molded mesh can range from 0.2 mm to 1 mm or from 0.4 mm to 0.8 mm or from 0.5 mm to 0.7 mm. The number of filaments woven into the braided mesh to form the expandable basket can vary in the range from 5 to 150 or from 10 to 60 or from 15 to 50 or from 16 to 32. The filaments made by the molding process can have some specific aspects. For example, the diameter of the filament does not have to be consistent over its entire length, but can vary along its length. For example, the filament can have a different (e.g., reduced) diameter in at least one intersection area compared to the rest of the filament. In a specific example of the intersection of two filaments, at least one of the filaments forming the intersection can have a reduced diameter and / or cross-sectional area at and / or near the intersection area participating in the intersection. In one example, when the diameter of the filament is reduced in a specific area, the reduced filament diameter can be reduced by an amount, for example, 0.1% to 90%, or 0.5% to 75%, or 1% to 60% compared to the non-reduced filament diameter. In one example, when the cross-sectional area in a specific area is reduced, the reduced cross-sectional area can be reduced by an amount of 0.1% to 90%, or 0.5% to 75%, or 1% to 60% compared to the non-reduced cross-sectional area.

[0135] Reducing the filaments at and / or near the intersection regions may help to mechanically stabilize the braided mesh, and thus the expandable basket, by providing more stable intersections, and / or may help to reduce the maximum diameter of the folded expandable basket. Having filaments with reduced diameter at and / or near the intersection regions can ensure that during expansion and contraction of the basket assembly (expandable basket), the intersections of the filaments remain relatively stable in terms of filament length. This means that in the contracted state of the basket assembly (expandable basket) as well as all expanded states, the filament intersections maintain a relatively same filament length distance. The mutual angle of the specific filaments creating the intersections changes (e.g., from about 2 degrees to 178 degrees and vice versa). Some minor longitudinal movement of the intersections may not be completely avoidable, but remains within limits that do not compromise the dimensional and / or mechanical stability of the braided mesh. Then, this feature can, for example, allow placement of electrodes at the intersections of the filaments and / or ensure a stable, predictable desired mutual position and / or their mutual distance of the electrodes.

[0136] On the other hand, filaments made by a molding process may have a variable cross-sectional shape. For example, it may be advantageous in the intersections of the filaments, where different cross-sectional shapes of at least one of the filaments included in the intersection can help to stabilize the intersection and / or can help to reduce the maximum diameter of the expandable basket in its contracted configuration. The cross-sectional shape used at and / or near the intersection region of the filaments included in the filament intersection can be, for example, semi-circular, rectangular, flat, oval or, for example, egg-shaped, while the cross-section of the rest of the filament can be different, for example, circular. In cases where the cross-section of the filaments at and / or near the intersection region includes flat or flattened sides, the flat or flattened sides can be the sides in contact with another filament forming the intersection.

[0137] A combination of variable cross-section and variable diameter of the filaments is also possible. For example, the filaments can have different cross-sections and different (e.g., reduced) diameters at and / or near the intersection regions, which can again contribute to stabilizing the braided mesh and thus to the expandable basket and reducing the maximum diameter of the expandable basket in its contracted configuration. The maximum diameter of the expandable basket in its contracted configuration can be reduced, for example, by 0.01% to 50%, or by 0.05% to 30%, or by 0.1% to 15%.

[0138] Variable diameter and / or variable cross-section can be used not only at and / or near the filament intersection regions, but also in different regions of the filaments. For example, diameter reduction and / or cross-section change can allow formation of weaker and / or more rigid regions on the filaments, such as forming living hinges during the filament molding process.

[0139] In another example, the molded filaments need not be molded straight, but may already be formed with at least one bend or curvature (2601). The bend and / or curvature (2601) may be located, for example, at and / or adjacent to at least one intersection region of the filaments, or, for example, adjacent to the proximal or distal end of the filaments. An example of such a solution can be seen in Figure 26 In the preformed curvature (2601) can be used, for example, for further stabilization of the braided mesh and thus for further stabilization of the expandable basket. The filaments can be preformed in such a way that thermal stabilization after braiding the braided mesh may not be necessary.

[0140] On the other hand, the filaments can be molded to include at least one region where the filaments are split during the molding process and / or at least one region where additional loops (2201) are formed on the filaments (415). Such at least one split region and / or additional loop (2201) can be formed, for example, at and / or near at least one filament intersection region (2202) and can be used, for example, as a support (fixation) at at least one intersection of two filaments (415) after the filaments (415) are braided into a braided mesh. In another example, the filaments can include electrodes within the slit (e.g., within the region defined by the start and end of the filament slit) and / or within the filament loop region (2203) defined by the first connection point (2204) of the loop (2201) with the filament (415) and the second connection point (2204) of the loop (2201) with the filament (415), which can be seen in Figure 22 In

[0141] The intersection region of the filaments is the region on the filaments that participates in the intersection in the braided mesh structure. In some cases, at least one electrode can be placed at and / or near the intersection region on the filaments. In the case where the electrode is located at and / or adjacent to the intersection region of the first filament included in a particular intersection, the second filament included in that intersection may not include an electrode located at and / or adjacent to the intersection region of that particular intersection. This means that there may be at most one electrode at any intersection of the braided mesh and the expandable basket. On the other hand, in the case where the intersection includes an electrode, it can be included at and / or near the intersection region of the filaments that has a greater lateral distance from the longitudinal axis in that particular intersection, which means that the electrode is placed on the outer periphery of the expandable basket.

[0142] In an example with a molded filament, as described above, such a molded filament may have a different diameter and / or cross-section in at least one crossover region compared to the rest of the filament. In a particular example, where an electrode is included in the crossover, the first filament including the electrode may have a cross-section corresponding to the cross-section of the electrode in the crossover region (e.g., a circular cross-section), and may include a loop at or near the crossover region. The second filament in the crossover may have, for example, a smaller diameter and / or a different cross-section compared to the rest of the filament (e.g., may have a flat, rectangular, oval, or semi-circular cross-section in the crossover region and a circular cross-section in other regions).

[0143] However, this does not mean that the filament including the electrode at or near the crossover region cannot have a different diameter or a different cross-section in the crossover region. For example, the electrode included on the filament may have a different diameter or a different cross-section compared to the rest of the filament.

[0144] A further option is to enhance the mechanical stability of the filament. Using a multi-layer wall may be one of the options. The wall of the filament may include, for example, more than one layer of material. Materials with different properties can be used, and the combination of these materials can result in a more mechanically stable wall and thus a more mechanically stable filament. Such a combination can use layers made of different materials from a group of polymers or thermoplastics, e.g., nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or, for example, silicon. Another possible option is to use layers of the same material, but different subgroups of each layer of material have different properties. The material used in a particular layer can be further enhanced, for example, by glass fibers.

[0145] On the other hand, for example, the filament can be further mechanically strengthened by inserting a mechanical support into the lumen of the filament. Such a mechanical support can, for example, have the form of struts placed in the lumen of the filament. The struts can be placed along the entire length of the filament, or, in the case where the filament does not have a lumen along its entire length, along the entire length of the lumen of the filament. Another possible option is to place the struts only in a part of the length of the lumen, thus leaving a part of the filament strengthened with struts and another part without strut strengthening. The struts can be made of, for example, nitinol, for example, having an electrically insulating layer, for example, made of polyamide (PA), polyimide (PI) or PTFE. Other possible materials suitable for the struts can be polymers or thermoplastics, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET) or, for example, silicon.

[0146] In an example with a molded filament, at least one reinforcing strut (2702) can be placed in the mold (2701) and overmolded. In this example, the strut (2702) must be made of a material with a melting point higher than that of the filament. The at least one strut (2702) can again be placed along the entire length of the filament or only in a part of the length of the filament, thus leaving a part of the filament strengthened with struts and another part without strut strengthening. Examples of struts that have been placed in the mold can be seen in Figure 27 in.

[0147] Another option for further strengthening the filament is to fill at least part of the lumen of the filament with glue or a molten polymer or thermoplastic material.

[0148] The braided mesh can be constructed such that all filaments contained within the braided mesh can be strengthened, or only a part of the filaments contained within the braided mesh can contain a reinforcing material while the other part of the filaments can be without a reinforcing material.

[0149] At least one filament forming the braided mesh can include at least one location where the local mechanical strength of the filament structure is weaker than that of the remaining filaments. Such a location can form a so-called active hinge (2103), as Figure 21As shown schematically. The active hinge can be used to define more or less precise positions at which the filaments, including those within the braided mesh, are more likely to bend, and thus the filaments within the expandable basket are more likely to bend, and form a smaller radius of curvature (or a direct kink) on the filaments compared to filaments without such an active hinge. This can further contribute to defining a more predictable shape of the expanded expandable basket in at least one deployed position. Creating such an active hinge on the filaments can include thinning or cutting a portion of the filaments. Thinning can be done, for example, by squeezing or thermoforming a specific location of the filaments. The thinning can be done around the entire circumference of the filaments or only partially. Partially asymmetric thinning may be advantageous because the hinge formed in this way can define a specific direction in which the filaments are more likely to bend than in other directions. In an example of an expandable basket, the active hinge formed on the filaments can allow the filaments to bend more easily, and thus the braided mesh to bend more easily, for example, in a radial direction from the longitudinal central axis of the catheter. For example, creating an active hinge with a smaller radius of curvature or a kink on the filaments in the distal body portion (421) of the basket assembly body or in the terminal assembly region can contribute to shaping the expandable basket (the basket assembly body) in a region located distally of the plane intersecting the portion of the basket with the highest diameter (in one of its expanded configurations), such that at least some of the distal portions of the expandable basket (in the region of the distal body portion) can form a larger angle (radially from the elongate axis) compared to the proximal portion of the basket (in the region of the proximal body portion). In an extreme case, the distal portion of the expandable basket (in the region of the distal body portion) can form an angle of 90° or greater (radially from the elongate axis) to achieve an expanded state in which at least a portion of the expandable basket, including the electrodes, becomes the most distal portion of the catheter longitudinally, without any other portion protruding further distally (e.g., the terminal assembly). Such a configuration may be advantageous, for example, in ablation of relatively flat treatment sites.

[0150] In an example where the expandable basket is made of a molded mesh, or in an example where the expandable basket includes filaments made by a molding process, the active hinge can be made directly during the molding of the molded mesh or the molded filaments, for example, by reducing the diameter of a portion of the molded mesh or filaments and by changing at least one aspect of the cross-section of a portion of the molded mesh or filaments.

[0151] At least one of the aforementioned active hinges may be included on at least a portion of the braided mesh, where the filaments are merged together (in the merged structure). In this case, the active hinge is a location on the merged structure where its local mechanical strength is weaker than the rest of the merged structure and can be formed, for example, by thinning or cutting the merged structure after merging. Another option for establishing an active hinge on the merged structure is to pre-thin or pre-cut the polymer tube before inserting the filaments, especially in the case where the merged structure includes a polymer tube and the filaments are merged in the inner lumen of the tube or in multiple inner lumens of a multi-lumen tube. Such pre-thinning of the tube can be accomplished, for example, by extrusion, thermoforming, or by molding (e.g., injection molding).

[0152] The active hinge may be formed within the region of the distal body portion, the central body portion, and / or the proximal body portion of the basket assembly body. In the case where the active hinge is located in the region of the proximal body portion, the active hinge can be placed, for example, in the proximal region of 0% to 20% or 0% to 15% or 0% to 10% of the contracted basket length. In the case where the active hinge is located in the region of the distal body portion, the active hinge can be placed in the distal region of 0% to 20% or 0% to 15% or 0% to 10% of the contracted basket length. The active hinge can also be part of the terminal assembly. In the case where the active hinge is placed in the central body portion, the hinge can be placed on a plane intersecting the basket assembly at the portion with the highest diameter, or at a distance from -20% to +20% or from -10% to +10% or from -5% to +5% from the plane or the center of the folded basket.

[0153] The expandable basket may include one or more electrodes or a set of electrodes. The electrodes can be configured to generate an electric field for ablating tissue, or to obtain or transmit at least one of an electrical signal or other signals, for example, for tissue mapping, ECG monitoring, impedance measurement, and / or detecting signals in contact with tissue. Another function of the electrodes can be used as a marker for X-rays. The electrodes can be coupled to specific filaments of the expandable basket. The electrodes can be placed on each filament or only on some filaments. Each filament including an electrode can include one or more electrodes, for example, 1 to 15, or 1 to 10, or 1 to 6, or 1 to 3 electrodes. The electrodes can be of one type or different types. The total number of electrodes placed on the expandable basket can range from 1 to 200, or from 5 to 100, or from 10 to 50, or from 15 to 40, or from 20 to 35. In the fully expanded configuration of the expandable basket, the spatial distance between the electrodes can range from 0.1 mm to 15 mm, or from 0.5 mm to 10 mm, or from 1 mm to 6 mm, or from 2 mm to 4 mm.

[0154] The electrodes can operate individually or in pairs or in groups, or some of the electrodes can operate individually and some can operate in pairs or in groups.

[0155] In one example, the electrodes may be placed in the region where the filaments cross (filament cross-point). Such a location may be advantageous because it is possible to maintain a more stable distance between the electrodes during different configurations of the expandable basket, and such a configuration can also advantageously prevent unwanted contact between the electrodes, especially when the expandable basket is not in a fully expanded configuration.

[0156] All the electrodes included in the expandable basket may be located at the filament cross-points, or only some of the electrodes may be located at the filament cross-points and some of the electrodes may be located elsewhere.

[0157] Each filament may also include one type or different types of electrodes, or different filaments may accommodate different types of electrodes. Different types of electrodes can be understood as electrodes having different functions, such as ablation electrodes, measurement electrodes, etc., or physically different electrodes having, for example, different shapes, sizes, designs, materials, etc., or a combination of electrode types having different functions and physical characteristics. For example, in a configuration where ring electrodes are placed on the filaments, all the electrodes may have the same diameter and may have different lengths, so there may be, for example, two or more sets of such electrodes, each set having a different length. The number of electrodes in each set may be the same or different. In an extreme example, each electrode on the expandable basket may have a different length. In a configuration 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 may have 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.

[0158] In one example, there may be a first set of 5 to 20 shorter electrodes, with a length of, for example, 0.3 mm to 3 mm, and a second set of 5 to 30 longer electrodes, for example, with a length of 0.6 mm to 4 mm. Advantageously, the electrodes from the first set can be used for at least one type of measurement, such as for intracardiac electrogram (EGM) measurement or ablation, and the electrodes from the second set can be used for ablation independently or in combination with the electrodes from the first set.

[0159] The electrodes can be placed on the body of the basket assembly. For example, the electrodes can be placed on the central or distal body portion, and in some cases, the electrodes can even be placed on the proximal body portion. Other electrodes can be placed on or within the outer elongate shaft, inner elongate shaft, catheter distal tip, or terminal assembly. In configurations where the electrodes are placed on the elongate shaft, distal tip, or terminal assembly and annular electrodes are used, the electrodes 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 can have a diameter 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.

[0160] The electrode layout on the expandable basket can ensure a continuous circular ablation zone while the expandable basket is in the expanded position and can form a pattern.

[0161] For example, the electrode layout on the expandable basket can ensure a continuous circular ablation zone and can form a pattern even when the expandable basket is maintained at various expanded positions between the fully contracted and fully expanded positions.

[0162] Additional electrodes (e.g., electrodes placed on or within the outer elongate shaft, inner elongate shaft, catheter distal tip, or terminal assembly) can be part of the pattern or can operate independently of the other electrodes. For example, the electrodes in the catheter distal tip or terminal assembly region can be used for spot ablation. There can be special dedicated electrodes in the region of the distal tip or terminal assembly, or for example, the metal portion of the terminal assembly can be used as an electrode, or a combination thereof is also possible.

[0163] The pattern (701) formed by the electrodes (109) can be, for example, a circular pattern in the space around the longitudinal central axis (203), at least when the expandable basket (409) is in one of its expanded configurations, as Figure 7A shown. Other two-dimensional or three-dimensional patterns formed by the electrodes (109) are possible. The pattern (701) can be centered around the longitudinal central axis (203) or can be not centered around the longitudinal central axis. The pattern (701) can have different shapes, including but not limited to circular, oval, square, rectangular, polygonal, planar, or other shapes, or the placement of the electrodes (109) on the expandable basket can be irregular. For example, there can be one pattern (701) in a plane, or multiple patterns (701) in a plane, or multiple patterns (701) in different planes.

[0164] The pattern formed by the electrodes can be located on the body of the basket assembly, particularly on the distal body portion, central body portion, or proximal body portion, as Figure 7BAs shown. The pattern can even extend to more than one of these parts. For example, for the treatment of a flat treatment site located away from the basket assembly, the electrode pattern can advantageously be positioned on the distal part of the basket assembly. In particular, the pattern can be positioned in a cross-section of the basket assembly that is defined by a region at an angle (703) of 0 to 90° with respect to the central axis (203) and the center of the plane (425), which plane intersects the basket assembly in the part with the highest diameter (in one of its expanded configurations). In some configurations, the pattern can be partially positioned on the distal part of the basket assembly body and partially on the central part of the basket assembly body. In some configurations, the pattern can be positioned in a cross-section of the basket assembly that is defined by a region at an angle (705) of 0° to 120° with respect to the central axis (203) and the center of the plane (425). This placement of the pattern can be particularly advantageous for the treatment of ostium, such as, for example, the pulmonary vein ostium. In the case where the treatment site has a tubular shape, the pattern can be placed in the middle part of the basket assembly, in particular in a cross-section of the basket assembly that is defined by a region at an angle (707) of 45° to 135° with respect to the central axis (203) and the center of the plane (425). If the flat treatment site is located at the proximal end of the basket assembly, such as, for example, the septum, the electrode pattern can be located on the proximal body part of the basket assembly, or partially on the proximal body part and partially on the central body part, in particular in a cross-section of the basket assembly that is defined by a region at an angle (709) of 90° to 180° with respect to the central axis (203) and the center of the plane (425). Optionally, the electrodes can be placed in all parts of the basket assembly, thereby forming a pattern in all parts, and only the pattern that is necessary or optimal for performing a specific treatment can be selected to perform the treatment.

[0165] A particular pattern can be formed by all or only some of the electrodes placed on the expandable basket. At various expanded positions between the fully folded and fully expanded positions of the expandable basket, the pattern can have a different number of electrodes. The distance between adjacent electrodes in the pattern can be, for example, from 0.1 mm to 15 mm, or from 0.5 mm to 10 mm, or from 1 mm to 6 mm or from 2 mm to 4 mm.

[0166] The electrode is electrically connected to the pulse generator, for example, through a wire. The electrode can be electrically or communicatively connected to other units or components of the pulsed electric field ablation device, and is, for example, electrically or communicatively connected to a mapping device, an EP display device, a pacing device, an ECG recording device, a catheter signal interconnection circuit, an ECG trigger circuit, an electrical control circuit, a GUI unit, or a remote control unit. In addition to the annular electrode mentioned above, the electrode can have any of many different shapes, for example, a tube wound around a filament, a coiled metal sheet, a square and / or rectangular or other shaped conductive material attached to a filament. Other possible forms of the electrode (109) can be an elongated continuous electrode stretched along the surface of a part of the filament (415) such that the electrode does not contact the intersection of the filaments (415) in the braided mesh (413), as Figure 8 shown. The electrode (109) can be attached to a specific filament (415) of the expandable basket in any way, for example, by mechanical attachment, swaging, curling, gluing, laminating, depositing, and / or welding. The electrode can be made of any conductive material, for example, copper, gold, steel, titanium, platinum, platinum-iridium, etc. In the case where at least one filament is made of a conductive material, the filament can also be used as an electrode. In the case where the entire conductive filament is not insulated, the entire filament can be used as an electrode, and in the case where the filament is, for example, partially electrically insulated, the exposed non-insulated part can be used as an electrode.

[0167] The wire can provide an electrical connection between the electrode and the pulse generator. The wire can be a part of the structure of the basket assembly (401). For example, as Figure 6C or Figure 9 shown, the wire (417) can be at least partially located in the lumen (601) of the filament (415). There can be one or more wires (417) coupled to each electrode, or one or more electrodes can be coupled to a single wire. The wire (417) can be incorporated into a wall of the shaft assembly, for example, incorporated into the wall of an outer elongated shaft. The wire can also be located in the central lumen of the outer elongated shaft, or there can be a separate lumen in the outer elongated shaft suitable for placing the wire. The wire can terminate near the electrode, or can spatially pass further along the length of the filament through the electrode. The wire can be located, for example, along the entire length of the filament of the basket assembly. Optionally, some wires (417) can terminate near the electrode, while other wires can spatially pass further along the filament through the electrode, or can be located along the entire length of the filament of the basket assembly.

[0168] The design of the expandable basket is particularly advantageous when the wire is positioned along the entire length of the filament, where the filament is bent and returned to the expandable basket rather than cut at the distal end of the expandable basket. Since a particular wire is configured to conduct electrical pulses between the electrode and the pulse generator, insulation of the cutting filament with the wire inside would be very challenging in the terminal assembly. On the other hand, in an example including a bent filament with a wire inside, insulation of the terminal assembly can be easily ensured.

[0169] The material for the wire can be any conductive material, for example, copper, stainless steel, steel, nitinol, aluminum, gold, platinum, silver, etc. The wire can be insulated or uninsulated. The wire can be insulated with any suitable material, for example, polyimide, polyurethane, polyester, polyvinyl chloride (PVC), rubber, rubber-like polymers, nylon, polyethylene, polypropylene, silicone, fiberglass, ethylene propylene diene monomer (EPDM), different fluoropolymers (e.g., polytetrafluoroethylene (PTFE)), etc. The wire can be made of a single conductor or a group of conductors, and a wire made of a group of conductors is sometimes referred to as a "cable". If the wire is insulated, the minimum breakdown voltage of the wire insulation should be at least 100V, 500V, 1000V, 4000V, or 10000V. The diameter of the wire with insulation may be limited by the dimensions of other structures of the device, for example, the filament and the minimum voltage that the filament must be able to carry without a breakdown risk. The typical diameter of the wire with or without insulation can be between 0.05mm and 0.7mm, or between 0.07mm and 0.5mm, or between 0.1mm and 0.3mm, or between 0.11mm and 0.2mm, or between 0.12mm and 0.18mm.

[0170] The construction of a braided mesh made of an electrically insulating material (as described above, with one or more wires inside the hollow filament) may be particularly advantageous for an ablation system based on the pulsed electric field ablation principle. The pulsed electric field ablation method further described requires generating an electric field around the electrode. To generate the electric field, electrical pulses must be conducted by a particular wire between the electrode and the pulse generator. When the filament is non-conductive and the wire is kept inside the filament as described herein, electrical insulation of the particular wire can be ensured even at a voltage level of several kilovolts (e.g., from 1 kV to 10 kV) carried by the wire. However, a braided mesh with at least one or more filaments made of a conductive material (e.g., nitinol, copper, stainless steel, steel, aluminum, gold, platinum, or silver) can also be selected. Such conductive filaments can be insulated or uninsulated, or only partially insulated. The filaments can not only conduct current but also act as electrodes (when uninsulated or only partially insulated) and / or as a further mechanical support for the braided mesh, thus acting as an expandable basket.

[0171] Another advantage of the braided mesh made of polymer or thermoplastic elastomer filaments is that it is easy to manufacture compared to metal braided meshes. The braided mesh can be made, for example, with the aid of a three-dimensional mandrel device. The specific filaments forming the braided mesh can be placed on the mandrel in a desired pattern. The filaments may already include electrical wires. The entire structure can then be heated, for example, close to the melting point of the filament material, and then the structure can be rapidly cooled. Compared to most metals, filaments made of thermoplastic elastomers or polymers generally require lower temperatures to reach the melting point, so the manufacturing process can be faster, more efficient and can require less energy input. Another advantage of this manufacturing process is that the electrical wires do not need to be heated to extreme temperatures that may damage the electrical properties of the wires. This can occur, for example, when the braided mesh is made of metal wires (metal filaments), where the braided mesh wires (filaments) also serve as conductive metal wires.

[0172] The braided mesh with inserted electrical wires can be connected to an external elongate shaft and an internal elongate shaft to form part of an expandable basket and basket assembly. Before or after connecting the braided mesh to the elongate shaft, electrodes can be connected to specific filaments of the braided mesh. The pulse generator is the component that generates electrical signals for the catheter electrodes. The pulse generator can allow setting, for example, the amplitude, shape and / or the number of pulses during activation of the electrical pulses. The pulse generator can also diagnose the electrical waveform to measure power. The pulse generator can operate synchronously with an ECG device or another part of the ablation system or device.

[0173] Furthermore, a method of ablation using the pulsed electric field ablation device is disclosed.

[0174] One method includes the step of placing a catheter (105) through a blood vessel near a treatment site (e.g., a heart chamber) in a patient's body. The catheter (105) can be inserted percutaneously into the patient's blood vessel.

[0175] Other support structures and / or devices can be used to help guide the distal end of the catheter to its desired location. Examples of such devices include wires or sheaths. The distal tip of the catheter can be advanced proximally in a contracted state to the treatment site, for example, through a sheath. In the contracted state, the diameter of the basket assembly at the distal tip of the catheter can be less than or approximately equal to the diameter of the external elongate shaft of the catheter. This configuration allows easy access to the distal tip of the catheter near the treatment site.

[0176] The treatment site can be located in the body, for example, within or on the heart, for example, within a heart chamber, particularly, for example, within the left atrium of the heart. The treatment site can include, for example, the ostia of the pulmonary veins. Other locations of the treatment site can be, for example, all tubular tissues, organs or blood vessels within the body, or, for example, a tumor site.

[0177] When the distal end of the catheter is delivered to the treatment site, the basket assembly of the catheter unfolds from a contracted or semi - contracted configuration to an expanded configuration. This unfolding can be caused by the pre - stretched shape of the braided mesh or its filaments, or by the linear displacement of an inner elongate shaft along the longitudinal central axis of the catheter against an outer elongate shaft, by the tension of an additional support structure (e.g., an inner coil or an inflatable balloon (not shown)), or by a combination thereof.

[0178] Then, the distal tip (107) of the catheter can be positioned near the target tissue of the treatment site (1001). For example, at least a portion of the basket assembly (401) and / or a portion of the expandable basket (409) is in contact with the treatment site (1001). At this position, at least a portion of a set of electrodes (109) placed on the basket assembly (401) can be in contact with the tissue of the treatment site (1001). In Figure 10 a schematic diagram of an example position can be seen. The terminal assembly (411) can improve the contact between the electrode and the treatment site through its flat design without a distal protruding structure. When there is no distal protruding structure on the basket assembly (401), especially on the distal part (405) of the basket assembly, it is easier to make the electrode contact the treatment site even when the treatment site is relatively flat.

[0179] After positioning the distal end of the catheter near the treatment site, an optional measurement step can be performed with or without the catheter. Different types of measurements can be carried out, for the purpose of, for example, diagnosing the type or quality of the tissue at or around the treatment site, the spatial position of the distal tip of the catheter, especially, for example, the spatial position of the distal tip of the catheter against the treatment site, the contact of the distal tip of the catheter and / or a specific electrode with the target tissue of the treatment site, or for the purpose of understanding the electrophysiological processes of the tissue adjacent to the electrode. For example, the electrode can also be used to measure the contact with the target tissue and can be placed on the expandable basket, for example, on the filaments of the braided mesh. The measurement electrode can be a different electrode from the ablation electrode, or the ablation electrode can be used for measurement. A separate measurement electrode can also be combined with an ablation electrode having a measurement function on a distal tip of a catheter. Separate measuring devices can be used to perform the measurement step, such as a separate measuring catheter (not shown), an ECG device including an ECG triggering circuit, an ECG recording device, an ECG electrode, an intracardiac ECG (EGM), an intracardiac echo device, an esophageal temperature measuring device, a fluoroscopy device, an RTG device, an MR device, etc. During the ablation process, the measurement step can be performed once, or can be repeated several times.

[0180] Ablation of the target tissue of the treatment site (1001) uses, for example, the principle of pulsed - electric - field ablation caused by pulsed electric fields with appropriate parameters. Although the terms "electric field" or "pulsed electric field" are mentioned herein, the electric fields considered herein can also include magnetic components.

[0181] The processes of basket assembly deployment, measurement, and ablation can be carried out in several stages. For example, an expandable basket can be delivered near the treatment site in a fully collapsed configuration. After delivery, it can be expanded to its first expanded configuration. For example, a pre-stretched shape of a braided mesh and / or filaments can cause this first transformation. In this configuration, for example, further operations on the basket assembly, as well as measurement and / or ablation, can be performed. Further repositioning, measurement, and / or ablation can also be carried out in any order at this location.

[0182] Then, the basket assembly can be expanded into a second expanded configuration. The second expanded configuration can be achieved, for example, by the linear displacement of an internal elongate shaft along the longitudinal central axis of the catheter against an external elongate shaft. In this configuration, for example, further operations on the basket assembly, as well as measurement and / or ablation, can be performed. Further repositioning, measurement, and / or ablation can also be carried out in any order at this location.

[0183] For example, the basket assembly can be expanded to several different deployed positions during which further repositioning, measurement, and / or ablation can be carried out.

[0184] In the case of pulmonary vein isolation ablation, the set of electrodes can form a circle around the pulmonary vein ostium. After ablation, the shape of the ablated tissue can also be a circle around the pulmonary vein ostium. By repositioning the basket assembly or by switching between different electrodes, several shapes of ablated tissue can be formed.

[0185] Pulsed electric fields (PEFs) are formed, for example, by electrical pulses, such as high-frequency electrical pulses. The electrical pulses can be generated by a pulse generator and can be delivered to the target tissue in the form of pulsed electric fields (PEFs) through electrodes that can be placed at the distal tip of the catheter and can be in electrical contact with the pulse generator. The electrical pulses can be formed by a variety of electrical pulses ranging from single-phase (unipolar) pulses to symmetric and / or asymmetric biphasic pulses. The pulses can also be combined with additional pre-pulses or additional measurement pulses for tissue conditioning. The pulses can be individual pulses or can be repeated in bursts, where the parameters of the pulses can vary or remain constant. The pulse bursts can also be run in sequence. The maximum amplitude of the pulses can depend on the target tissue, the size of the electrodes, and / or the distance between the electrodes in order to form an electric field with a maximum electric field amplitude, for example, between 0.1 kV and 10 kV or between 0.4 kV and 5 kV or between 0.5 kV and 2 kV per centimeter in the target tissue volume. The duration of the pulses can range from the nanosecond range to the millisecond range, for example, from 2 ns to 10 ms, or from 10 ns to 5 ms, or from 10 μs to 1 ms. The shape of the pulses can be, for example, square, a curve similar to exponential discharge, rectangular, sawtooth, triangular, or sinusoidal.

[0186] The pulses can be single-phase or biphasic. The biphasic pulses can be symmetric or asymmetric. The pulses can repeat from 1x to 100,000x. The frequency of the high-frequency pulses can vary from 0.1 Hz to 10 Hz. The amplitude (Um) of the single-phase pulses can vary from 100 V to 10 kV, while the peak-to-peak amplitude of the biphasic pulses can vary from 200 V to 20 kV.

[0187] Figure 16 It can be an example of a possible part of a pulsed electric field ablation (PFA) protocol and an illustration of terms and expressions regarding the PFA protocol. The 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 a certain hierarchy, for example, trains (TR) and bursts (B).

[0188] The electrical pulses (1601) can be defined by, for example, the shape, amplitude (Um) with a specific voltage, and the pulse length with a duration (t1). In the case of single-phase pulses, the pulse amplitude (Um) can be negative or positive (the pulse can have a negative voltage or a positive voltage). The electrical pulses (1601) can be separated from each other by inter-pulse pauses (1603), which are defined by a duration (t2) and a voltage (Up). The voltage during the inter-pulse pause (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 pulses (1601), especially up to 50% of the amplitude (Um) of the adjacent electrical pulses. In the case where the electrical pulse has a positive amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) will remain positive between 0 V and the amplitude (Um) of the electrical pulse (1601), and in the case where the electrical pulse (1601) has a negative amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) will remain negative between 0 V and the amplitude of the electrical pulse (Um). Figure 17a An example of an inter-pulse pause (1603) with a voltage different from 0 V is shown. The biphasic pulses can be symmetric or asymmetric in at least one of time, amplitude, or energy.

[0189] Figure 17bAn example of a biphasic electrical pulse is shown. The biphasic pulse can have a positive phase (1701) of the same amplitude (voltage) and a negative phase (1703) of the same duration (t10, t12) (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). Then, the resulting pulse can have the same energy in the positive and negative phases of the pulse, or the energy in the positive and negative phases of the pulse can be different. A biphasic pulse having the same energy in both phases can be referred to as a symmetric biphasic pulse. The symmetric biphasic pulse can be balanced (when the duration and amplitude of the two phases of the pulse are the same), or unbalanced (when the amplitude and / or duration of each phase is different). An asymmetric biphasic pulse has phases with different energies. Exemplary biphasic pulses A, B, C do not have a pause (inter-phase pause) between specific phases of the pulse, and exemplary pulse D is a biphasic pulse having an inter-phase pause (1705). The duration of the inter-phase pause of the pulse can range from 0 μs to 50 μs or from 0 μs to 10 μs or from 0 μs to 5 μs.

[0190] A series or sequence of pulses in a row, with or without an inter-pulse pause, can be referred to as a train (TR). A particular train (TR) can be characterized, for example, by a duration (t4) or the number of pulses, and can be separated from each other by an inter-train pause (1607) having a duration (t5), or the inter-train pause (1607) can separate the trains with individual single pulses. A series or sequence of trains (TR) and inter-train pauses (1607) can be referred to as a pulse train (B), and can be characterized, for example, by a duration (t6), the number of trains (TR), the number of pulses, or an inter-pulse-train pause (1615) (having a duration (t7) between specific pulse trains (B)).

[0191] As described above, the voltage value (Up) at the electrode may not drop to 0 V between pulses, especially during the inter-pulse pause (1603), but may remain at a level at which the risk of electrolysis or bubble generation due to temperature rise is absent or very small, for example, up to 50% of the amplitude (Um) of the adjacent electrical pulse. This can also reduce the unwanted relaxation of polar molecules, which can result in a shorter length of at least some parts of the PFA protocol and thus increase the efficacy of the PEF therapy.

[0192] When applying pulses with an amplitude (Um) of several hundred volts to several thousand volts, there is a certain risk of causing ventricular muscle depolarization and unwanted ventricular rhythms in the heart, even when applied in the atrium. Depolarization can be caused directly by the electric field or by secondary energy induction in another device, such as a catheter placed in or near the atrium or ventricle or both. Timing the active sequence (individual pulses, trains, and / or bursts) with the following pauses creates an effect called overdrive. The overdrive effect is commonly used in ablation catheterization to suppress the risk of adverse cardiac rhythms by using an external pacemaker. The advantage of the proposed PFA protocol is that, in the case where the therapeutic (ablative) electrical pulse causes myocardial depolarization, it can also act as a pacing stimulus pulse for the heart, so there is no need to use an additional pacing device (e.g., an external pacemaker) to synchronize the pulses of the pacing device with the therapeutic pulses of the PFA protocol. This in turn means that, in such cases, 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 the ablation pulses accordingly.

[0193] The duration (t8) of one cycle (1609) of the burst (B) and the inter-burst pause (1615) between bursts is between 201 ms and 800 ms, given by the range between the need to safely deliver pulses faster than the patient's actual heart rate (overdrive effect) and the need to keep the heart rate at a safe level (allegedly about 220 beats per minute minus age). In the PFA protocol, the cycle duration can be fixed or variable within a specified range (201 ms to 800 ms), e.g., according to a sine or trigonometric function. An individual burst (B) can have a duration (t6) ranging from 1 ms to 200 ms, or 30 ms to 180 ms, or 60 ms to 160 ms, which is the safe time to contract the ventricle by applying the burst (B), protecting the ventricle from damage or unwanted rhythms. The burst (B) duration (t6) can also be fixed or variable within a specified range (1 ms to 200 ms) within the PFA protocol, e.g., according to a sine or trigonometric function.

[0194] The PFA protocol may have other positive effects on ablation results, such as reducing the risk of causing adverse ventricular rhythms and / or maximizing the efficiency of PEF application.

[0195] However, electroporation has been described as the main trigger for cardiomyocyte death following the application of PEF, but actual cell death can also be caused by, for example, the electrical breakdown of the cardiomyocyte membrane, mitochondria, or nucleus; by tearing individual cardiomyocytes / cardiomyocytes (or cell populations) of the myocardium (e.g., by disrupting intercalated discs, directly by the electric field or by mechanical disruption through supercontraction); by damaging the sarcolemma or myofibrils of muscle fibers; due to the depletion and insufficient production of ATP in cardiomyocytes caused by overcontraction; by relaxing the intercellular junctions of cardiomyocytes; by muscle cell myolysis; by wrinkling of cardiomyocytes either directly under the influence of the electric field or by mechanical damage through supercontraction; by irreversible damage to calcium cycling (whether it is the non - physiological function of the sarcoplasmic reticulum or ion pumps or calcium channels or calcium - binding proteins); by calcium overload - mitochondrial swelling in cardiomyocytes (due to overcontraction 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.

[0196] An electric field can be formed between one or more electrodes placed at the distal tip of a catheter and a reference electrode placed at a distance, e.g., on the patient's skin. In some aspects, the reference electrode can have a surface area much larger than the sum of the surfaces of the active distal tip electrodes. This mode of action is generally referred to as monopolar. Another option for forming an electric field is the bipolar mode. In this mode, the electric field appears between two or more distal electrodes of different polarities that are typically placed close together or adjacent to each other. In this case, the sum of the surfaces of the active electrodes with the first polarity is similar to the sum of the surfaces of the active electrodes with the second polarity.

[0197] In some aspects, the electrodes (109) placed on the distal assembly can operate in a hybrid mode of the two previous types. An example of this mode is Figure 11 shown. In this mode, only the electrodes 109 placed on the distal tip 107 are used for ablation. There is a first single electrode or a group of electrodes operating in a mode with a first polarity (P1) and a second single electrode or a group of electrodes operating in a polarity (P2) (which can be the opposite polarity) different from the operating mode of the first electrode or group of electrodes. The surface or the sum of the surfaces of the first electrode or the first group of electrodes is significantly smaller than the surface or the sum of the surfaces of the second electrode or the first group of electrodes. For example, there can be a third group of electrodes operating in a third mode in a high - impedance (HI) state, where the impedance of the third group of electrodes is, for example, higher than 500 Ω. The electrodes operating in the third mode can be adjacent to the first electrode or group of electrodes operating in the first mode.

[0198] One advantage of electrode operation in this hybrid mode is that, compared to the bipolar mode, the generated electric field can have a more uniform current density. Another advantage of the hybrid operation mode is that, compared to the bipolar mode, the electric field formed in this mode can reach deeper into the target tissue in some respects. In the case of ablating a cardiac chamber, the depth of the ablated target tissue (in one example, the target tissue may include myocardial tissue) can reach 5 mm.

[0199] Figure 12 A variant of the hybrid operation mode of the electrode (109) is shown, in which a group of electrodes (more than one electrode) operates in a mode with a first polarity (P1). The functional principle of this operation mode is similar to the variant in which one electrode (109) operates in a mode with a first polarity (P1). For example, the sum of the surfaces of the electrodes operating in a mode with a first polarity (P1) is significantly smaller than the sum of the surfaces of the electrodes operating in a mode with a different polarity (P2).

[0200] For example, in cases where reducing the electrode size is advantageous, an example where a group of electrodes (more than one electrode) operates in a mode with a first polarity (P1) is more advantageous than an example where a single electrode operates in a mode with a first polarity (P1). Reducing the size of the electrodes may be advantageous or necessary in cases where an increase in the number of electrodes is needed or desired. For example, in cases where more precise mapping of the treatment site or more precise and / or uniform ablation of the target tissue at the treatment site is needed, a larger number of electrodes is required. Since the treatment site can be part of the human anatomy, the overall size of the pulsed electric field ablation device (especially a catheter with a distal tip of the catheter) must be limited according to the human anatomy. It follows that if the ablation device requires more electrodes, for a certain number of electrodes, the size of the electrodes must be limited to fit within the limited size of the critical components of the pulsed electric 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 this arrangement helps to increase the ablation depth.

[0201] Smaller-sized electrodes can have other advantages. For example, in an example where the same electrode is used for ablation and measurement, this means that the same electrode must be configured to deliver high-voltage pulses and record measurement values. For example, in the measurement of an ECG signal, smaller electrodes may be advantageous.

[0202] However, there are also some challenges with smaller electrodes. In an example including pulsed electric field ablation, an electric field is formed between the electrodes, for example, by an electrical pulse, such as a high-frequency electrical pulse generated by a pulse generator. To effectively ablate the entire target area of the treatment site, it may be important to form an electric field with a maximum electric field amplitude of several hundred volts to several thousand volts per centimeter in the target tissue volume. Using smaller electrodes means a smaller surface area of the electrodes. Compared with larger electrodes having a larger surface area, electrodes with a smaller surface area must have a higher induced voltage on the electrodes to achieve the desired electric field density in the target tissue. The adverse effects of such a configuration may include a higher electric field density, a higher electric field strength, and / or possible sparks at the edges of the electrodes. However, using a selected set of electrodes (more than one electrode) operating in a mode with a first polarity instead of a single electrode operating in a mode with a first polarity can address and overcome some or all of these problems. When a carefully selected first set of electrodes operates in a mode with a first polarity, a second set of electrodes operates in a mode with a different polarity, and a third set of electrodes may operate in a third mode in a high-impedance state, the first set of electrodes and / or the second set of electrodes can act as virtual electrodes. This means that the electrodes in the first set can act together as one virtual electrode, and / or the electrodes in the second set can act as another virtual electrode. With such a configuration, the electric field strength and / or density near the electrodes can be reduced. Other positive effects of such a configuration can be reducing the risk of sparks and increasing the ablation depth, or increasing the depth of the ablated tissue at the treatment site.

[0203] The enlargement of the surface area of the electrodes in the first set and the resulting formation of the virtual electrode can lead to a reduction in the voltage required to be induced in the electrodes and / or the elimination of sparks, mainly at the edges of the electrodes. However, the concept of the disproportionate surface areas of the electrodes in the first and second sets can be retained, which means that the surface area or the sum of the surface areas of the first electrode or the first set of electrodes is significantly smaller than the surface area or the sum of the surface areas of the second electrode or the second set of electrodes. The ratio of the surface area or the sum of the surface areas of the first set of electrodes to the sum of the surface areas of the second set of electrodes can be between 2:3 and 1:100, or 3:5 and 1:80, or 3:5 and 1:70, or 1:2 and 1:50, or 1:2 and 1:40, or 1:2 and 1:30, or 1:2 and 1:20, or 1:3 and 1:15, or 1:3 and 1:10, or 1:4 and 1:8.

[0204] Adding electrodes to a first set of electrodes operating in a mode with a first polarity can significantly reduce the electric field strength near the electrodes. For example, using four electrodes instead of one in a first set of electrodes operating in a mode with a first polarity, the electric field strength at the electrode surface is reduced by a quarter, while in an example using three electrodes, the electric field strength is reduced by half. This reduction in strength can allow for the use of a lower voltage on the electrodes compared to a solution where only one electrode operates in a mode with a first polarity. By increasing the area of the electric field at a certain voltage per centimeter, this reduction can additionally or alternatively increase the depth of ablation of the target tissue. The voltage value per centimeter in the electric field region can be, for example, from 50 V / cm to 3000 V / cm, or from 100 V / cm to 1500 V / cm, or from 250 V / cm to 1000 V / cm.

[0205] Specific electrodes on the distal tip of the catheter can be switched to one or more modes during ablation. The specific electrodes can be switched during one ablation cycle or several ablation cycles. During one ablation cycle or several ablation cycles, the electrodes can be switched to one or more modes several times. In some aspects, it is even possible to have two or more sets of electrodes operating simultaneously in a mode with a first polarity, while one set of electrodes operates with a different polarity, with or without electrodes operating in a high impedance state.

[0206] A specific electrode can be switched to one of the modes, for example, before or after each pulse, before or after several consecutive pulses in a train of pulses, before or after one or several trains of pulses in a burst of pulses, or for example, before or after a burst of pulses or several bursts of pulses.

[0207] Taking into account the hybrid operating modes of the electrodes and / or the goal of forming virtual electrodes, an electrode layout or spatial pattern on the distal tip can be formed. Since the electrodes can be switched to one or more modes during ablation, it is possible that the resulting virtual electrodes can have different spatial shapes, which means that the electric fields formed around and between the virtual electrodes can have different shapes, with different magnetic field structures and / or different electric field densities and intensities. Examples of the spatial pattern of the electrodes on the distal tip, especially on an expandable basket, can be seen in Figure 13A and Figure 13B A front view of a basket assembly (401) with a spatial pattern of electrodes (109) is shown, the electrodes being adapted to form virtual electrodes by switching the electrodes (109) to different operating modes with a first polarity and with a different polarity and / or with a high impedance state. Figure 13A

[0208] Figure 13B ​A front view of the basket assembly (401) is again shown, which has an electrode spatial pattern adapted to form virtual electrodes by switching the electrodes (109) to different modes. However, this time, the electrodes are placed in the regions (filament intersections) where the filaments (415) cross each other.

[0209] A possible layout of the electrodes switched to the hybrid operation mode can be seen Figure 14 , which is also a front view of the basket assembly (401). The first group of electrodes (109) operates in a mode with a first polarity (P1) and together forms a first virtual electrode (1401). Another group of electrodes (109) operates in a mode with a different polarity (P2) and together forms a second virtual electrode (1403). In this configuration, when an electrical pulse is transmitted from the pulse generator (103) to the electrodes (109), an electric field will be formed between and around the virtual electrodes (1401, 1403). Some electrodes (109) can operate in a third mode, for example, in a high impedance (HI) state.

[0210] The electrodes in the high impedance (above 500 Ω) state can help shape the electric field formed between and around the electrodes in the first and second groups of electrodes and / or between or around the virtual electrodes. In one example, assigning the high impedance state to the electrodes that are spatially adjacent to the electrodes operating in the mode with the first polarity can have a positive impact on the shape of the electric field compared to the operation mode of the electrodes not in the high impedance state, such that a part of the electric field capable of causing ablation reaches deeper into the target tissue of the treatment site. This phenomenon may have a positive impact on the quality and uniformity of the ablation process. The electrodes in the high impedance state can be placed spatially between the first and second groups of electrodes.

[0211] An exemplary pattern of the electrode (109) is shown in more detail in FIG. 15A. The electrode (109) forms a repeating cross or square or rectangular pattern on the filaments (415) of the woven mesh in an expanded configuration of the expandable basket. Viewed from this view perpendicular to the cross-section (e.g., contacting the expandable basket at the intersection (1501) of four adjacent electrodes), the pattern appears two-dimensional, but is actually three-dimensional because the electrode (109) is fixed to the filaments (415) of the woven mesh or is part of the filaments of the woven mesh, which forms the expandable basket, so the pattern conforms to the curvature of the expandable basket. In an embodiment using a set of electrodes operating in a mode with a first polarity (P1), such a pattern of the electrodes is advantageous. In this example, a set of four adjacent electrodes operating in a mode with a first polarity (P1) and thus forming a first virtual electrode (1401) will have a cross shape as shown in FIG. 15A, or a square or rectangle as shown in FIG. 15B. The advantage is that the two virtual electrodes (1401) formed by the two shapes, in combination with the second virtual electrode, and possibly with the help of electrodes in a high impedance state, can form an electric field having a specific quality (shape, amplitude, density, potential gradient) suitable for ablation of the target tissue.

[0212] FIG. 15C shows an example of an electrode pattern, where the electrode (109) is located in the region where the filaments (415) cross each other (filament cross-point). Also shown herein is an exemplary set of electrodes operating in a mode with a first polarity (P1).

[0213] 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 a set of electrodes forming a virtual electrode can be different in a contracted configuration and / or different expanded configurations of the expandable basket. For most expanded configurations of the expandable basket, the rectangles and squares formed by the above electrodes will be tilted and will form a shape closer to a rhombus or rhomboid. The same applies to the angles between the two dashed lines forming the cross and passing through the electrodes, which are not right angles in most deployed configurations.

[0214] Figure 34 A layout of an exemplary pattern of the electrode (109) included on the expandable basket is shown imprinted in a flat two-dimensional plane. The electrodes are placed in such a pattern that in all expanded configurations of the expandable basket, the distance (3401) (measured perpendicular to the central axis (203) at ±45°) between the closest points of electrodes (109) longitudinally adjacent to each other in the direction of the central axis (203) ±45° is less than 2 mm. An example of such a pair of electrodes (109) longitudinally adjacent to each other in the direction of the central axis (203) ±45° can be seen in Figure 34 An example of such a pair of electrodes (109) longitudinally adjacent to each other in the direction of the central axis (203) ±45° can be seen.

[0215] When using high-voltage pulses in the human body, for safety reasons, it may be necessary to synchronize the delivery of the pulses with the cardiac cycle, for example, in order to avoid ventricular arrhythmias. The pulsed electric field ablation device may incorporate or use means for such synchronization, including triggering the pulse delivery through such synchronization means. The synchronization means may be, for example, an ECG device.

Claims

1. An ablation device for tissue pulsed field ablation, the device comprising at least one pulse generator and a catheter.

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