Pulse field ablation apparatus and method

Abstract

An ablation device and method for pulsed field ablation includes a catheter including an expandable basket, a set of electrodes formed on the expandable basket, and a pulse generator adapted to generate electrical pulses, the pulse generator being in electrical communication with the set of electrodes. The expandable basket is formed of a braided mesh of filaments, the filaments being made of a non-conductive material, at least a portion of the filaments having a lumen, the lumen including a fusible material, and the filaments further including an electrode and a conductive wire. The conductive wire extends at least partially through the lumen of the filament and is electrically connected to the electrode.

Description

Technical Field

[0001] The present invention relates to an ablation apparatus and method, and more particularly to an apparatus and method for pulsed field ablation of a target tissue by a pulsed electric field in which one of the main principles of ablation can be irreversible electroporation of cell membranes.

Background Art

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

[0003] Catheter ablation typically involves advancing one or more flexible catheters subcutaneously into the patient's blood vessels, in the case of cardiac ablation via either the femoral vein, internal jugular vein, or subclavian vein. The catheter is then advanced towards the target treatment site on the inside or surface of the heart.

[0004] The main means of ablation treatment for arrhythmias is either to directly remove by destroying the arrhythmogenic substrate or to prevent the spread of non-physiological action potentials by linear or circular isolation. All of these approaches basically require the formation of lesions where the action potential of the myocardium does not spread. By applying energy, a small portion of the myocardium is locally destroyed and converted to non-myocardial connective tissue by natural physiological processes within a few weeks.

[0005] Common ablation methods known from the prior art are based on thermal destruction of tissue by either high or low temperatures. Such methods include, for example, heating the target tissue by a high-frequency field (RF) or laser, or freezing the tissue by cryoablation. These methods cause necrosis of the target tissue, which can add risks to the procedure.

[0006] In recent years, methods and apparatus that utilize electric fields for ablation have been employed. The aim of these methods is to induce tissue destruction by inducing irreversible electroporation of cell membranes instead of destruction by high or low temperatures, thereby reducing the shortcomings and risks of ablation procedures that are primarily based on thermal damage. However, there are still shortcomings that need to be addressed.

[0007] A common design for such a device may be a catheter having a distal tip with one or more electrodes. The catheter may, for example, have one active electrode at its tip. Irrelevant electrodes may be placed, for example, on the patient's skin. Ablation of the targeted treatment site using such a device must be performed one point at a time, which increases the duration and complexity of the procedure.

[0008] Another example of a conventional device is a catheter with electrodes arranged in a row at the distal end of a single catheter body. The distal end of such a catheter is delivered near the target treatment site and unfolded (bent) into a specific shape near the target treatment site. In such a shape, two or more electrodes can be used for treatment, and little movement at the distal end is required, but unfolding the catheter into the correct shape, properly positioning it, and further manipulating it can be very difficult. Similarly, irrelevant electrodes can 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 having a catheter terminal basket containing a single strut with electrodes are also known from the prior art. Such devices can ensure easier deployment and positioning to the target site. Typically, a catheter terminal has more electrodes, so ablation can be either unipolar, with unrelated electrodes placed, for example, on the patient's skin, or bipolar, between specific electrodes of the catheter terminal. One drawback of this solution is the limited number of struts, which means that a limited number of electrodes create a specific circular pattern in space. This drawback stems from the need for mechanical stability of specific struts so that the basket can maintain a stable shape. This means being sufficiently rigid, and the struts must maintain specific dimensions. The number of struts used is then limited by the size of the catheter. Another drawback of this solution is that such a structure cannot fully guarantee the relative distance of the struts in the deployment configuration, which means that the distance between electrodes cannot be guaranteed either. This means that the device may need to be repositioned multiple times to ensure proper ablation, which prolongs the duration of the procedure.

[0010] While there is a need to improve the quality and safety of ablation, there is also a need to reduce patient risks and treatment duration. Therefore, there is a need for improved ablation devices and methods that are less complex, have improved quality and reliability of the methods and devices themselves, and are gentler and safer for patients. [Overview of the Initiative]

[0011] This specification discloses ablation systems and methods, in particular ablation methods and apparatus for pulsed field ablation by electric field, which can address and solve the aforementioned problems, are gentler and safer for the patient, reduce time and technical complexity, and improve the quality, effectiveness and reliability of the system, method and apparatus itself. [Brief explanation of the drawing]

[0012] Exemplary aspects of the present disclosure are shown by way of example in the accompanying drawings, and like reference numerals indicate the same or similar elements.

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

[0014] [Figure 2] It is an overview of an exemplary pulsed field ablation device equipped with a catheter.

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

[0016] [Figure 3B] It is an exemplary representation of a cross-section of the shaft assembly.

[0017] [Figure 4] It is an exemplary representation of the distal tip of a catheter having a basket assembly in an extended configuration.

[0018] [Figure 5] An exemplary distal tip of a catheter having a basket assembly in a folded configuration is shown.

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

[0020] [Figure 6B] It is a detailed view of an exemplary expandable basket having filaments.

[0021] [Figure 6C] It is a detailed view of an exemplary expandable basket having filaments and conductive wires.

[0022] [Figure 7A] Front view of an exemplary distal tip of a catheter.

[0023] [Figure 7B] Side view of an exemplary distal tip of a catheter.

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

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

[0026] [Figure 10] Exemplary schematic view of the position of a basket assembly adjacent to a treatment site.

[0027] [Figure 11] Schematic view of an exemplary mode of operation of an electrode.

[0028] [Figure 12] Schematic view of another exemplary mode of operation of an electrode.

[0029] [Figure 13A] Example of a spatial pattern of electrodes at the distal tip of a catheter.

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

[0031] [Figure 14] Diagram of a possible layout of electrodes already switched to a hybrid mode of operation.

[0032] [Figure 15A] An exemplary pattern of electrodes is shown.

[0033] [Figure 15B] Another exemplary pattern of electrodes is shown.

[0034] [Figure 15C] Another exemplary pattern of electrodes is shown.

[0035] [Figure 16] A portion of an exemplary pulsed field ablation protocol is shown.

[0036] [Figure 17a] This shows an example of a pulse pause using a voltage different from 0V.

[0037] [Figure 17b] Examples of different two-phase pulses are shown.

[0038] [Figure 18] This is a diagram of an example of a terminal assembly.

[0039] [Figure 19] Another diagram of an exemplary terminal assembly is shown.

[0040] [Figure 20] An example of filaments joined together at their intersections is shown.

[0041] [Figure 21] This is a diagram of the distal portion of a basket assembly having a joint structure and a living hinge.

[0042] [Figure 22] An example of a filament produced by the molding process is shown.

[0043] [Figure 23] This is a diagram illustrating an example of a partially braided mesh containing filaments manufactured by a molding process.

[0044] [Figure 24a] This is an example of a flat braided mesh produced by a molding process.

[0045] [Figure 24b] This shows a flat, molded braided mesh bent into the shape of a tube.

[0046] [Figure 24c] This shows multiple flat-formed meshes bent into the shape of a tube.

[0047] [Figure 25a] This is a diagram illustrating an example of a molded mesh formed as a three-dimensional structure.

[0048] [Figure 25b] This is a diagram of an example of a molded, expandable basket.

[0049] [Figure 26] Two filaments fabricated by molding to create a combined structure are shown.

[0050] [Figure 27] This shows an exemplary arrangement of mold components configured for filament injection molding.

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

[0052] [Figure 29] This diagram shows an example of the inner elongated shaft ends and expandable basket before and after their mechanical mounting.

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

[0054] [Figure 30b] A detailed diagram of an exemplary projection of the internal elongated shaft is shown.

[0055] [Figure 31a] This shows a cross-section of the filament during the manufacturing process.

[0056] [Figure 31b] This shows a cross-section of the filament at another manufacturing step.

[0057] [Figure 31c] This shows another cross-section of the filament at a different manufacturing step.

[0058] [Figure 32] This is a block diagram of the pulse generator.

[0059] [Figure 33] This is a schematic diagram of the improved half-bridge.

[0060] [Figure 34] This shows the layout of electrodes imprinted on a two-dimensional plane. [Modes for carrying out the invention]

[0061] Detailed explanation Figure 1 shows an ablation system (100) for pulsed-field ablation of target tissue. The ablation system (100) described herein includes a pulsed-field ablation device (101). The ablation system (100) may include, or be connected to, other parts or devices suitable for performing or supporting the pulsed-field ablation method described herein. Other parts or devices may include, 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), an ECG electrode (125), a pacing device (131), a catheter signal interconnection circuit (119), and / or an electrophysiology (EP) display device (133), and may include an EP recording system. The EP display device may display and / or record data from one or more other devices connected to the ablation system (100). Furthermore, the ablation system (100) may include a mapping device (135), such as a three-dimensional (3D) mapping device or a real-time position measurement (RPM) device, and / or an unrelated electrode (127). The mapping device (135) records, for example, an EGM (electrocardiogram) of the location in space measured by the catheter and creates a map of the surface of the heart. This may also indicate the position and orientation of the catheter. Other possible methods for measuring the actual position of the catheter may be via a sensor within the catheter (e.g., magnetic-based position measurement), or by using, for example, impedance measurement at electrodes on the catheter, or measurement based on high frequency or a combination thereof. Advantageously, in some examples, the catheter used for position measurement is the same catheter used for ablation.

[0062] The pulsed field ablation device (101) includes a pulse generator (103) for generating short, high-voltage electrical pulses, and a catheter (105) suitable for insertion into a patient's body cavity, having a distal tip (107) suitable for performing pulsed field ablation of target tissue using a pulsed electric field with 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 electrical pulses having frequencies, for example, 0.1 Hz to 10 Hz, with the amplitude of single-phase pulses varying from 100 V to a maximum of 5 kV, and the peak-to-peak amplitude of two-phase pulses varying from 200 V to 10 kV. The pulse duration can range from nanoseconds to milliseconds. An exemplary schematic of the generator (103) is shown in Figure 32.

[0064] The generator (103) may include a power supply unit (3200) capable of generating an operating voltage at its output, for example, 100V to 5000V, 250V to 2000V, or 500V to 1000V. The power supply unit (3200) may also transmit, for example, AC current from a current source (3202) to the DC current at the output of the power supply unit (3200), for example, from a plug. The power supply unit (3200) may have an output power of 100W to 5000W, or 200W to 3000W, or 500W to 1000W. The power supply unit (3200) may include a regulator (3201) for adjusting the generation of the operating voltage. The operating voltage can be adjusted, for example, by switching it on or off according to feedback from the output of the power supply unit (3200). The power supply unit (3200) may include, for example, a switching-mode power supply (3208) configured to vary the voltage coming from a current source (3202), for example, from about 230V to about 400V, a safety transformer (3209) (e.g., an AC-DC transformer), a power factor correction circuit block (PFC) (3210), 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 configured to switch on and off according to signals from the electrical control circuit (115), for example.

[0065] The output 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, 50 μF to 1500 μF, or 80 μF to 1000 μF, or 160 μF to 750 μF. The capacitor unit (3203) may include an emergency system (3207) that can cause emergency dissipation of charge from the capacitor unit (3203) in the event of any failure or if any measured parameter is outside the safe boundary of the pulse field ablation device (101). The emergency system (3207) may include a safety discharge resistor configured to safely discharge the capacitor (3212), a thyristor protection and / or contactor configured to short-circuit the capacitor (3212) if necessary, for example. The operating speed of the emergency system (3207) may be, for example, 50 ms to 100 ms.

[0066] The generator may further include a switching unit (3204) which may include at least one switch (3205), such as a semiconductor switch. The input of the switching unit (3204) may be coupled to a capacitor unit (3203), and the output of the switching unit (3204), and therefore the switch (3205), may be coupled to at least one electrode (109), which may be configured to switch the electrode (109) between 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). A single switch (3205) may be coupled to one electrode (109) or more electrodes.

[0067] The switch (3205) may be a semiconductor switch, for example, 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 conventional half-bridge. This solves the parasitic characteristics of the conventional half-bridge, which are the closed-state leakage current and output capacitance. The improved half-bridge (3300) may include a top and a bottom. The upper transistor (3301) is coupled to a common collector. The emitter of the upper transistor (3301) is coupled to ground with an upper resistor (3302). Due to the placement of the upper resistor (3302), the voltage across the upper resistor (3302) is close to zero when the upper transistor (3301) is closed. The improved half-bridge (3300) may further include an upper diode (3303). The upper diode (3303) is coupled to the emitter of the upper transistor (3301) via its anode and to the output (OUT) of the half-bridge (3300) via its cathode. When the upper transistor (3301) is closed (high impedance state), the upper diode (3303) can ensure that current from the output of the half-bridge (3300) does not pass through the upper 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) is close to zero when the bottom transistor (3304) is closed. The bottom diode (3306) is connected in reverse; that is, the anode of the bottom diode (3306) is coupled to the output (OUT) of the improved half-bridge (3300), and the cathode is coupled to the collector of the bottom transistor (3304), preventing the output (OUT) of the improved half-bridge (3300) from having a permanent output voltage.

[0068] In cases where the switching unit (3204) is directly coupled to the capacitor unit (3203), patient or operator safety may depend on the reliability of at least one switch (3205). In the event of a switch (3205) failure, the patient or operator may face uncontrolled high capacitance dissipation of the capacitor unit (3203) for a period of 50 ms to 100 ms.

[0069] For example, to address such hazards to patients or operators, at least one DC / DC converter unit (3206) can be coupled between the capacitor unit (3203) and the switching unit (3204). The DC / DC converter unit (3206) may have an input voltage of 100V to 5000V, 250V to 2000V, or 500V to 1000V, and an output voltage of 150V to 5000V, 500V to 3000V, or 1000V to 2000V. 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 capacitance from the output capacitor (3213) and interrupt the voltage delivery from the generator (103) to the electrode (109) in the event of any fault or any of the measured parameters outside the safety boundary of the pulse field ablation device (101). 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 contactor configured to short-circuit the output capacitor (3213) if necessary, for example. The emergency dissipation of capacitance from the output capacitor (3213) and the interruption of the voltage supply from the generator (103) to the electrode (109) may occur in less than 50 ms, or less than 25 ms, or less than 15 ms, or less than 5 ms, or less than 1 ms, or less than 100 μs, or less than 10 μs.

[0071] The capacitance of the output capacitor (3213) may be, for example, 1 μF to 200 μF, or 1.5 μF to 100 μF, or 2 μF to 50 μF, or 5 μF to 30 μF. The DC / DC converter unit (3206) may be, for example, a DC / DC converter without feedback. The DC / DC converter unit (3206) may be configured to convert the high capacitance of the capacitor unit (3203) to a lower capacitance in the output capacitor (3213). The DC / DC converter unit (3206) may be further configured to rapidly discharge the capacitance of the output capacitor (3213). The DC / DC converter unit (3206) may be further configured to limit the leakage current from the power supply unit (3200) to the patient to, for example, less than a limit of 10 μA. The leakage current may be generated, for example, by the parasitic capacitance of the windings of the power supply unit (3200). The DC / DC converter unit (3206) may include two windings and may be, for example, a series resonant converter. The DC / DC converter unit (3206) may have conversion ratios such as 1:1 to 1:6, or 4:5 to 1:4, or 2:3 to 1:3.

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

[0073] The electrical control circuit (115) evaluates the received data and, based on the received data, can transmit control signals to the power supply unit (3200), capacitor unit (3203), DC / DC converter unit (3206), current source (3202), switching unit (3204), and / or other parts of the ablation device (101). If at least one of the parameters being measured falls outside a predetermined boundary, the electrical control circuit (115) can transmit control signals to the power supply unit (3200), capacitor unit (3203), DC / DC converter unit (3206), and switching unit (3204), for example, to initiate a safe disconnection of a particular unit or all or a subset of units. Safe disconnection may mean, for example, turning off the power supply unit (3200) and activating the emergency system (3207) of the capacitor unit (3203) (discharging capacitor (3212) to the safety discharge resistor and / or short-circuiting capacitor (3212) via thyristor protection and / or contactor). In the DC / DC converter unit (3206), safe disconnection may mean activating the output capacitor emergency system (3214) (discharging output capacitor (3213) to the safety discharge resistor and / or short-circuiting output capacitor (3213) via thyristor protection and / or contactor). In the switching unit (3204), safe disconnection may mean disconnecting at least one switch (3205).

[0074] The pulsed-field ablation apparatus (101) may include, or be connected to, other parts or devices suitable for performing or supporting the pulsed-field ablation method described herein. These other parts or devices may include, 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), an ECG electrode (125), a pacing device (131), a catheter signal interconnection circuit (119), and / or an electrophysiological (EP) display device (133), and may include an EP recording system. The EP display device may display and / or record data from other devices connected to the ablation system (100). Furthermore, the ablation system (100) may include a mapping device (135), such as a three-dimensional (3D) mapping device or a real-time measurement (RPM) device, and / or an unrelated electrode (127). For example, the pulsed field ablation apparatus (101) may be configured for use inside or on the surface of a patient's heart, for example for the treatment of cardiac tissue, for example for pulsed field ablation of cardiac tissue, for example for pulsed field ablation of myocardial tissue, for example for pulmonary vein isolation. The apparatus and methods disclosed herein may be used in other locations, for example, in all tubular tissues, organs, or blood vessels in the body, or in sites of tumors, for example.

[0075] The catheter (105) shown in Figure 2 includes a shaft assembly (201) and a distal catheter tip (107) positioned adjacent to the distal portion of the catheter (105). The shaft assembly (201) defines the longitudinal central axis (203) of the catheter (105). The catheter (105) may further include a handle assembly (123) and a connecting assembly (121). The catheter (105) may be maneuverable or non-maneuverable and can be introduced to its position, for example, via an introducer sheath (not shown), with or without the help of a guidewire (not shown).

[0076] The connection assembly (121) of the catheter (105) may serve to interconnect the catheter (105) with other parts of the ablation system (100). The connection assembly (121) may include a single connection portion or more spatially separated connection portions. The connection assembly (121) may be located on the proximal portion of the catheter (105) and / or may be part of, for example, a handle assembly (123). The connection assembly (121) portion may include, for example, one or more electrical connections, mechanical connections, fluid connections, and / or inputs for a guidewire.

[0077] The connection assembly may include at least one connector, such as an electrical connector, a fluid connector, a data connector, or an optical connector. The connector may be used to connect and disconnect the catheter (105) to other parts of the ablation system (100).

[0078] The handle assembly (123) may be attached to the catheter shaft assembly (201) and may function, for example, for maneuvering and operating the catheter (105), and / or for precise control of the movement and flexure of the catheter (105). To enable the maneuvering function, there may be a knob (not shown) attached adjacent to the distal compartment of the catheter (105) supplied through a separate lumen and connected to a steering wire (not shown) which may be connected to a knob or steering mechanism (not shown) inside the handle assembly (123). The handle assembly (123) may further include a connecting assembly (121) or one or more connecting parts of the connecting assembly (121), and other parts, for example, a grip (not shown) and / or a deployment mechanism (not shown) for deploying / retracting the distal tip basket assembly (401, see Figure 4) and / or expandable basket (409) by pushing / pulling the inner elongated shaft (301) and / or outer elongated shaft (303) relative to each other. The deployment mechanism may include, for example, an actuator for moving the inner elongated shaft (301) longitudinally relative to the outer elongated shaft (303).

[0079] Figure 3A shows a catheter (105) having a shaft assembly (201). The shaft assembly may comprise an outer elongated shaft (303) and / or an inner elongated shaft (301). The cross-section of an exemplary shaft assembly (201) in cross-section AA shown in Figure 3B may include two concentric tubes, the outer tube being the outer elongated shaft (303) and the inner tube being the inner elongated shaft (301). The shafts can be translated longitudinally relative to each other along the longitudinal central axis (203). This translation may allow, for example, an expandable basket (409) to be unfolded / retracted from a folded configuration to a fully expanded configuration and then returned to its original position.

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

[0081] The body of the outer elongated shaft (303) may include one or more lumens (309, 311) extending along its entire length, for example, between the proximal and distal ends. The lumens may be fitted with, for example, a lead wire or a fluid, such as an irrigation fluid. One or more lumens may be configured to receive one or more inner elongated shafts. The body of the outer elongated shaft may be further defined, for example, by a proximal section (305) and a central section (307). The central section of the body may be designed with a flexible jacket compared to the proximal section to allow bending of the outer elongated shaft and to increase its flexibility. The proximal section may include a more rigid material jacket to increase the torque and stiffness of the body of the outer elongated shaft. Suitable materials for constructing the jacket include, but are not limited to, nylon, TPU, HDPE, or PEBA.

[0082] The body of the outer elongated shaft may include conductive wires. The conductive wires may pass through the central lumen (309) of the outer elongated shaft, or the outer elongated shaft may include several other lumens (311), so that one or more of the wires may pass through one or more of the other lumens (311). For example, the number of other lumens may correspond to the number of filaments in the braided mesh of the distal tip of the catheter; for example, if 20 filaments are used to construct the distal tip of the catheter, 20 other lumens may be used.

[0083] The conductive wires may extend from the basket assembly to a connecting assembly adjacent to, for example, the handle assembly.

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

[0085] Stiffness and torque are important characteristics that the outer elongated shaft should possess, and therefore the outer elongated shaft may include a braid of metal or rigid polymer wires wound laterally above / around the PTFE liner, for example, around the inner layer of the body, embedded in the outer jacket of the body in some embodiments, or may include, but not limited to, rigid polymers including polyimide, polyamide, polyetheretherketone (PEEK) or any other suitable material.

[0086] The outer layer of the outer elongated shaft may contain a laminated polymer to provide a seamless, smooth, and soft surface. As previously mentioned, the outermost layers of the central and proximal compartments may be formed from different polymers; for example, nylon material can be used for the proximal compartment, while PEBA, which is more flexible than nylon, can be used for the outermost layer of the central compartment. However, both compartments may have the same innermost layer. The outer elongated shaft may have a substantially constant outer diameter along its length.

[0087] The outer diameter (OD) dimension of the outer slender shaft may conform to, for example, the French catheter scale commonly used for standardizing catheter sizes. The diameter of this scale is defined in French units (FR), where 1 mm = 3 FR. The scale typically ranges from 3 FR catheters to 34 FR catheters. For example, the diameter of the outer slender shaft may be between 5 FR and 20 FR, or 7 FR to 16 FR, or 9 FR to 15 FR. The diameter of the central lumen of the outer slender shaft may be approximately 0.1 mm to 5 mm, or 1 mm to 4 mm, or 2 mm to 3.5 mm, or 2.5 mm to 3 mm.

[0088] The inner elongated shaft may include a proximal end, a distal end, and a body extending between the proximal and distal ends. The body of the inner elongated shaft may include, for example, one or more lumens (313) extending along the entire length of the inner elongated shaft between the proximal and distal ends, or it may not have lumens. One or more lumens (313) of the inner elongated shaft may be designed, for example, to accommodate a standard guidewire (not shown) and / or to guide a fluid, such as an irrigation fluid. The diameter of one or more lumens (313) may be 0.1 mm to 3 mm, or 0.5 mm to 1.5 mm, or 0.9 mm to 1 mm, or 0.94 mm to 0.99 mm. One or more inner elongated shafts may be suitable for placement in one or more lumens (309, 311) of the outer elongated shafts. The dimensions of the inner elongated shaft can be selected to match the diameter of the specified lumen of the outer elongated shaft, but the two structures still need to allow for their smooth relative movement. That is, the external dimensions of the inner elongated shaft (301) can be 0.1 mm to 4.9 mm, or 0.5 mm to 3.5 mm, or 1 mm to 3 mm, or 1.28 mm to 2.8 mm.

[0089] Since the inner elongated shaft may be suitable for housing the guidewire within its lumen, a low-friction liner for the inner lumen, such as a PTFE liner, can be used.

[0090] As described above, the inner elongated shaft can be translated relative to the outer elongated shaft to deploy the basket assembly / expandable basket, and thus, for example, a braided socket is woven along the length of the PTFE liner to form the body of the inner elongated shaft. In another embodiment, to improve its flexibility and torque, the body of the inner elongated shaft may include cut hypo tubing instead of braiding.

[0091] A polymer jacket can be melted / laminated laterally and above a layer having a braid or hypotube to increase the flexibility of the tube and provide a seamless surface. Various polymers can be used for the jacket, and exemplary materials may be nylon, polyether block amide (PEBA), polyether ether ketone (PEEK), or polyimide.

[0092] The distal tip (107) of the catheter in the example shown in Figure 4 further includes a basket assembly (401). The basket assembly (401) may comprise a proximal portion (403) of the basket assembly, a distal portion (405) of the basket assembly, and a basket assembly body (407) extending between the proximal and distal portions. The basket assembly body may include a central body portion (419) that occupies about one-third of the basket assembly body and extends around a plane (425) that intersects the basket assembly in the proximal and distal directions (in one of its extended configurations) where it has the largest diameter. The basket assembly body may further include a distal body portion (421) extending distally from the central body portion (419) and a proximal body portion (423) extending proximally from the central body portion (419), each of which occupies about one-third of the basket assembly body (407).

[0093] The basket assembly (401) comprises an expandable basket (409). The proximal portion (403) of the basket assembly may include an attachment of the proximal portion of the expandable basket (409) adjacent to 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 to one or more distal ends of the inner elongated shaft (301) that form the terminal assembly (411).

[0094] An example of the attachment of the distal portion of an expandable basket (409) adjacent to one or more distal ends of an internal elongated shaft (301) can be found in Figure 28. In this particular example, the distal end of the expandable basket (409) may be created with the assistance of a ring (2801) which is bent at a point (2804) where a filament (415) is fixed or fixed to a ring (2801). The distal portion of the expandable basket (409) is attached to the internal elongated shaft (301) by a mechanical locking mechanism. To lock the basket to the shaft, two projections (2802, 2803) are formed on the internal elongated shaft (301) to hold both sides (proximal and distal) of the distal end of the basket, for example, including a ring (2801) which locks the expandable basket (409) to the internal elongated shaft (301). The assembly is created, as shown in Figure 29, by pushing the prepared inner elongated shaft (301) having the first projection (2802) distally through an opening in the distal portion of the expandable basket, for example through a hole in the ring (2801), until the first projection (2802) on the shaft reaches the distal portion of the expandable basket from the proximal side. The inner elongated shaft end (2901) (the one projecting distally from the basket) is then tipped / heated in a bullet-shaped mold to form a second projection (2803) having a non-traumatic bullet-shaped end, which prevents the inner elongated shaft (301) from moving proximal to the expandable basket (409). This connection is made such that, under operating conditions, the inner elongated shaft (301) locks into the expandable basket (409), but also such that, under certain axial loads, the connection breaks and loosens if the basket cannot be unfolded and the catheter needs to be retrieved from the patient. The axial load (force) required to brake the connection may be 10N to 100N, 15N to 75N, or 20N to 50N.

[0095] The projections (2802, 2803) may also be formed on the inner elongated shaft by other techniques. One particular example is shown in Figures 30a and 30b. In this example, the second projection (2803) may be formed by a distal add-on (3001) coupled to the inner elongated shaft (301), for example, the end of the inner elongated shaft (2901). The distal add-on (3001) may take the form of a toroidal, cylindrical, conical, frustoconical, or hollow tubular body, for example, by forming a non-traumatic shape (e.g., bullet shape, flange shape) at the distal end to ensure that the terminal assembly does not mechanically injure the patient, and it may be made of plastic or metal, for example. The distal add-on (3001) may include a tubular structure (3002) projecting proximal to the second projection (2803) parallel to the inner elongated shaft. The distal add-on member (3001) and / or tubular structure (3002) may include, for example, at least a portion of the inner elongated shaft (301), e.g., the inner elongated shaft end (2901), and a cavity (3006) adapted to receive a guidewire. The cavity (3006) may have two internal diameters, namely, a first diameter (3007) formed proximally of the distal add-on member (3001) that is large enough to fit at least a portion of the inner elongated shaft (301), e.g., the inner elongated shaft end (2901), and a second diameter (3008) formed distal to the first diameter (3007) that is smaller than the first diameter (3007) and smaller than the outer diameter of the inner elongated shaft (301) through which the guidewire passes. This configuration of the cavity (3006) allows the distal add-on (3001) to act as a distal stopper for the inner elongated shaft (301) in the direction of the longitudinal central axis (203), while also preventing any potentially sharp edges of the inner elongated shaft end (2901) from being exposed distal to the distal add-on (3001) and potentially causing tissue damage upon contact.The distal extension member (3001) may be joined to the inner elongated shaft (301), and the joining may include, for example, crimping, welding, screws, threads, molten plastic, or adhesives, such as hot melt adhesive or glue.

[0096] In the specific examples shown in Figures 30a and 30b, the distal add-on (3001) may be bonded to the inner elongated shaft (301) by, for example, molten plastic or adhesive. The distal add-on (3001) may include a cavity having a diameter larger than the outer diameter of the inner elongated shaft (301), for example, 0.1% to 50%, or 0.5% to 40%, or 1% to 25% larger. The inner elongated shaft may be inserted into the cavity, and the resulting space (3003) between the inner elongated shaft (301) and the cavity wall may be filled with adhesive, for example, hot melt adhesive or glue. The distal add-on (3001) may include an opening (3004) for adhesive for this purpose, which may serve to allow the adhesive into the resulting space (3003). After filling the resulting space (3003) with adhesive, the adhesive opening (3004) can be closed and sealed, for example, by a plug, molten plastic, or adhesive, for example, by hot melt adhesive or glue, possibly the same type used to bond a distal add-on member (3001) to the inner elongated shaft (301).

[0097] The first projection (2802), as illustrated in Figures 30a and 30b, may be formed, for example, by a tubular proximal appendage (3005) coupled to the inner elongated shaft (301). The proximal appendage (3005) may be directly coupled to the inner elongated shaft (301), or it may be coupled to the inner elongated shaft (301), for example, to the tubular structure (3002), via a distal appendage (3001). In another example shown in Figures 30a and 30b, the proximal appendage (3005) may be coupled to the inner elongated shaft (301) both directly and indirectly via the distal appendage (3001). The connection of the proximal add-on member (3005) to the inner elongated shaft (301) and / or to the distal add-on member (3001) may include, for example, crimping, welding, screws, threads, molten plastic, adhesives, such as hot melt adhesive or glue, or, for example, another fixing member (not shown) positioned proximal to the inner elongated shaft (301). The first projection (2802) may have a shape and may include, for example, a plastic tube.

[0098] The ring (2801) to which the filament (415) is fixed may be connected directly to the inner elongated shaft (301) or via, for example, a distal add-on (3001) or a proximal add-on (3005). An example of a ring (2801) connected to the inner elongated shaft (301) via a distal add-on (3001) is shown in Figures 30a and 30b. In this particular example, the distal add-on (3001) includes a tubular structure (3002) projecting proximally from a second projection (2803) parallel to the inner elongated shaft, and the ring (2801) may surround the tubular structure (3002).

[0099] The terminal assembly (411) can be advantageously designed without, or with at least reduced, a structure that protrudes distally from the distal portion (405) of the basket assembly, for example, a cap or similar formation. This is particularly advantageous in situations where at least part of the ablation method needs to be performed on a relatively flat treatment site.

[0100] An exemplary solution for terminal assemblies may be an overmolded structure. The filaments can be fixed to each other and / or to the distal ends of the inner elongated shafts by an overmolding process to form an overmolded terminal assembly. Another fixing procedure (and / or terminal assembly fabrication procedure) similar to overmolding may be, for example, inclination, in which the filaments are at least partially melted and pressed into a pre-formed mold, and thus connected to each other and / or to the inner elongated shafts. Lamination is another exemplary process for fixing the filaments to their distal ends to form a terminal assembly. Terminal assemblies can also be fabricated by swaging or crimping the distal ends of the filaments. The filaments are joined together in the terminal assembly area and may be swaged or crimped together by, for example, some kind of metal ring.

[0101] In another example, the terminal assembly may be fabricated as a hinged mechanical structure as shown in Figure 18. For example, one or more filaments may be at their distal end in the region of the terminal assembly fixed to an articulated element (1801) which includes, for example, a lateral narrow portion (1803) and a distal portion (1805) that is wider than the lateral narrow portion (1803). The lateral narrow portion (1803) may be in the form of a pin having, for example, a square, rectangular, circular, elliptical, or other suitable cross-section. The distal portion (1805) may have, for example, an elliptical or circular shape, or in another example, a ball or sphere shape. Other possible shapes of the distal portion (1805) may be cylindrical, conical, cubic, or block. This can be the case, for example, when the entire joint element (1801) is made from a sheet of material (metal sheet, polymer sheet), or when it is not made from a sheet (for example, when the joint element is cast or forged), it can have one of the same dimensions as the narrower lateral portion (1803). The joint element (1801) may be made from, for example, metal (e.g., nitinol) or other material, such as polymer or thermoplastic. The filament can be fixed to the multi-joint element by, for example, welding, bonding or crimping. The joint area (1807) can be at least partially laminated, for example, to prevent possible tissue damage and to seal the assembly. The joint element is then fixed within a central bullet structure (1809). This may be a hollow structure having, for example, a cutting window (1811) suitable for accommodating the proximal portion (1803) of the joint element (1801). The distal portion (1805) of the joint element is, in this case, located in a cavity (1813) inside the hollow structure. In some examples, the distal portion (1805) of the joint element may have a larger dimension (cross-section or width) than the dimensions of the window (1811). This prevents the distal portion (1805) of the joint element (1801) from slipping through the window (1811), and thus the joint element is held in place, along with the distal portion of the filament attached to the connection region (1807) and the central bullet structure (1809).The central bullet structure (1809) may comprise several parts connected to one another (e.g., by welding, bonding, or other mechanical means such as snapping, threading, screws, bolts, etc.). It may also have different external shapes, e.g., cylindrical, spherical, or elliptical. The shape of the cavity (1813) may correspond to or differ from the external shape. The central bullet structure may include a fixing part (1815) for fixing the distal end of an inner elongated shaft to the central bullet structure. The fixing part (1815) may, for example, have the shape of a hollow tube connected to the central bullet structure. The fixing part is suitable for housing and / or connecting the distal end of the inner elongated shaft and can allow the flow and / or redirection of a fluid, e.g., an irrigation fluid coming out of the lumen of the inner elongated shaft. The fixing part may interfere with the cavity (1813) or may be mechanically and / or fluidly connected. This can be adapted, for example, by an opening (1901) as shown in Figure 19, to guide at least a portion of the irrigation fluid into the cavity of the central bullet structure.

[0102] Such hinged mechanical structures as described above can allow for easier radial movement of the filament (relative to the longitudinal central axis of the catheter) in the area of ​​the terminal assembly, which can be advantageous during operations with an expandable basket, particularly in transitions (unfolding / retracting) between a folded configuration and one or more extended configurations.

[0103] When metal components are used in the design of terminal assemblies, they can be used, for example, as electrodes for ablation or sensing, mapping, or a combination thereof.

[0104] The expandable basket may be attached to the inner and / or outer elongated shafts, for example, by bonding, welding, lamination, or by mechanical means.

[0105] The expandable basket (409) is configured for transitions (unfolding / retracting) between a folded configuration, as shown in Figure 5, and one or more expanded configurations. The transition (unfolding / retracting) may be caused by the shape of the pretension of the braided mesh (413) and / or the filaments (415), and / or by the linear displacement of the inner elongated shaft (301) relative to the outer elongated shaft (303) along the longitudinal central axis (203) of the catheter (105), or a combination thereof. Another possibility for the unfolding / contraction of the expandable basket (409) may be by the tension of an additional support structure, such as an inner coil or balloon (not shown).

[0106] The expandable basket may include filaments braided into a braided mesh or molded mesh. In a folded configuration, the cross-section of the expandable basket may be equal to or close in dimension to the cross-section of the outer elongated shaft, but in one embodiment, the cross-section of the expandable basket may be smaller than the cross-section of the outer elongated shaft and may depend on the dimensions of the outer elongated shaft. In an expanded configuration, the cross-section of the expandable basket may be significantly larger than the cross-section of the outer elongated shaft. A fully expanded expandable basket may have a maximum cross-sectional diameter of, for example, 20mm to 40mm, or 22mm to 38mm, or 25mm to 35mm. Such dimensions of a fully expanded expandable basket may be suitable for, for example, placement in the cavity of the heart. For larger body cavities, for example, the expandable basket may have larger dimensions, for example, 30mm to 150mm, or 40mm to 120mm, or 50mm to 100mm. In other situations, a fully expanded expandable basket with smaller dimensions may be suitable for smaller body cavities. Such smaller expandable baskets, when fully expanded, can have dimensions of, for example, 3mm to 25mm, 5mm to 15mm, or 7mm to 10mm.

[0107] In some embodiments, instead of the braided mesh (413) filaments (415) being cut adjacent to the distal portion of the expandable basket (409), the filaments (415) can be bent at the distal portion and attached adjacent to the distal portion of the inner elongated shaft to form a terminal assembly. The bent filaments may then be turned back toward the expandable basket (409) or the outer elongated shaft, where they can be terminated. Figure 6A shows in more detail an expandable basket (409) having bent filaments at its distal portion (603).

[0108] Expandable baskets made from braided mesh have advantages over conventional solutions with unbraided struts, in that the expandable basket has higher mechanical stability while using relatively thin filaments. The greater number of filaments in the structure can also allow for the use of more electrodes. Electrodes placed on the filaments can also be more optimally distributed, meaning they can be placed closer to each other, or a desired pattern can be created in the expandable basket. Another advantage of expandable baskets made from braided mesh is the higher mechanical stability of the structure, which can ensure a stable and predictable distance between electrodes.

[0109] The braided mesh may be heat-treated to ensure the deformation of the filaments and the fixation of such deformation. Such deformed filaments then ensure that the filament intersections (points where filaments intersect each other) remain relatively stable with respect to the length of the filaments during the expansion and collapse of the basket assembly (expandable basket). This means that the filament intersections remain relatively the same over long distances of the filaments in both the folded and fully expanded states of the basket assembly (expandable basket). What is changing is the relative angle of the specific filaments forming the intersection (e.g., from about 2 degrees to 178 degrees, or vice versa). Some kind of small longitudinal movement of the intersections cannot be completely avoided by this process, but is limited to the extent that it does not impair the dimensions and / or mechanical stability of the braided mesh. This feature, then, may allow, for example, to place electrodes at the filament intersections and / or ensure the stable, predictable, and desired relative positions of the electrodes and / or their relative distances.

[0110] Further structural stability of an expandable basket made from braided mesh can be achieved, for example, by joining certain filaments (included in the braided mesh) together. The filaments can be joined together, for example, at their intersections. An exemplary solution can be seen in Figure 20. The joint (2001) may be fixed (not allowing any mutual movement of the filaments at the joint) or it may be interacting (allowing some kind of mutual movement of the filaments at the joint). Joining can be achieved, for example, by bonding, welding, lamination, adhesive, binding (e.g., with some kind of string) or melting. Another option may be to bind the filaments together by a ring structure or crimping. If the ring structure is made from a conductive material (e.g., metal), it can also function as an electrode. The same applies to crimping. Metal connectors can also function as electrodes.

[0111] Structures adapted to join two filaments may already be present on the filaments even before braiding. In an example where at least one filament (415) is produced by a molding process, such as an injection molding process, the filament (415) may include at least one region where the filament is divided, and / or at least one region where an additional loop (2201) on the filament is formed during the molding process, as can be seen in Figures 22 and 23. Such at least one divided region and / or additional loop (2201) may be created, for example, in or adjacent to at least one filament intersection region (2202), which is a region of filament that intersects with another filament at an intersection (2301) of the braided mesh. A split or loop (2201) on the first filament (415) included in the intersection (2301) may be adapted to the insertion of the second filament (415) included in the intersection (2301), and thus function to facilitate the joining (fixing) of the two filaments (415) together at the intersection (2301). Such an intersection (2301) in which the filaments (415) are fixed by the loop (2201) or split may have similar properties to an intersection joined by, for example, tying a knot, but without the tying step.

[0112] In the example, if the first filament included in the intersection includes a loop in and / or adjacent to the intersection region involved in this intersection, then the second filament included in the intersection does not include a loop in and / or adjacent to the intersection region involved in this particular intersection, meaning that there can be at most one loop in any given intersection. The length of the loop in and / or adjacent to the intersection region on the first filament of the intersection (length from the connection point with the first filament to the connection point with the second filament) can 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), for example, 0.5mm to 10mm, or 1mm to 7mm, or 2mm to 5mm. The diameter of the loop's cross-section can be, for example, 0.1mm to 1mm, or 0.15mm to 0.7mm, or 0.2mm to 0.5mm.

[0113] All intersections within the expandable basket may be joined, or only some intersections may be joined while the remaining intersections are not.

[0114] In another example, an expandable basket may be fabricated by a molding process, such as injection molding. The mesh of the expandable basket may not be braided in this example, but it can be fabricated from a molded structure. There are several options for how to create an expandable basket by molding.

[0115] An expandable basket can be fabricated by at least one molded mesh in the form of a two-dimensional (flat, planar) structure (planar molded mesh) (2401), for example, as shown in Figure 24a. At least one planar molded mesh (2401) is configured to be molded into a three-dimensional shape after molding. At least one planar molded mesh can be removed from the mold after molding and bent into a tubular shape, for example, around a central longitudinal axis (203), as shown in Figure 24b. Figure 24c is an example of creating an expandable basket using multiple planar molded meshes. Each of the molded meshes (2401) can be bent into a shape that, in this example, individually forms only a portion of the intended tube (a portion of the circumference of the intended tube) and forms a complete tube when assembled. The edges (2402) of the molded meshes are then joined to each other (e.g., by welding, crimping, bonding, binding, etc.) to create a tubular structure. Subsequently, the distal portions (2403) of the tubular structure can be assembled and joined together, and possibly fixed to the distal portion of the inner elongated shaft, to create a terminal assembly, and thus an expandable basket. The proximal portion (2404) of the tubular structure can be joined to the distal end of the outer elongated shaft.

[0116] In another example, the expandable basket can be fabricated from a molded mesh that has already been formed as a three-dimensional structure. Figure 25a shows an example of such a structure, which may be, for example, a tubular molded mesh structure (2501). In this example, the step of bending a two-dimensional flat molded mesh can be omitted, but the tubular molded mesh structure has already been fabricated in a mold. Further steps are the same as in the previous example. The distal portion (2403) of the tubular molded mesh structure (2501) can be paired and joined together and possibly fixed to the distal portion of an inner elongated shaft, thus creating a terminal assembly, and therefore an expandable basket. The proximal portion (2404) of the tubular molded mesh structure (2501) may be joined to the distal end of an outer elongated shaft.

[0117] In a further example, as can be seen in Figure 25b, 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 relating to the distal portion (2502) of the expandable basket, which has already been molded together, and thus creates at least a portion of the terminal assembly in a single step, with the molding of the rest of the expandable basket. The molded distal portion (2502) of the expandable basket (409) can then be coupled to the distal end of the inner elongated shaft, and the proximal portion (2503) can then be coupled to the distal end of the outer elongated shaft.

[0118] The molded mesh, formed as a three-dimensional structure, can have shapes other than tubular. For example, it can be molded into the shape of an expandable basket in one of its expanded states.

[0119] A molded mesh, formed as a three-dimensional structure, does not need to be formed as a complete structure. However, it is possible to form several three-dimensional parts of the molded mesh and then join those parts together. These three-dimensional parts can individually create only a portion of the intended structure (e.g., a part of the circumference of a single tube or basket in an expanded state), and when assembled and joined together, they can form a complete structure.

[0120] In the example of an expandable basket made from molded mesh, electrodes, conductive wires, and / or other structures (e.g., tubes for forming lumens, reinforcing struts, etc.) may be placed in the mold before molding and can be overmolded during the molding of the molded mesh. Structures can be completely overmolded, meaning they are entirely inside the molded mesh and do not reach the surface of the molded mesh, and / or partially, for example, at least a portion of their surfaces are exposed to the surface of the molded mesh. For example, electrodes can be partially overmolded when at least a portion of their surfaces are exposed to the surface of the molded mesh. However, structures do not need to be overmolded, and at least a portion of them can be added to the molded mesh after the molding process of the molded mesh.

[0121] Molded mesh can be made from, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or polymers or thermoplastic elastomers such as silicone.

[0122] The specific openings (mesh, gaps) within the braided or molded mesh do not need to be of uniform size; in fact, the sizes of specific openings can vary. The size can increase, for example, from the distal and proximal portions of the expandable basket (which may be the smallest) towards the middle portion of the expandable basket (which 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 can increase, for example, linearly or exponentially. The circumference of the openings in the proximal and distal body portions may be, for example, between 1 mm and 40 mm, while the circumference 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 braided or molded mesh of the expandable basket may be between 4 and 40.

[0123] The ratio of the circumference of the smallest opening to the circumference of the largest opening of the expandable basket may be 100:101 to 1:80, or 20:21 to 1:50, or 10:11 to 1:40. The number of rows of openings can be counted from the first complete opening from the attachment of the proximal portion of the expandable basket adjacent to the distal end of the outer elongated shaft, to the last opening of the distal portion of the basket assembly terminated by the terminal assembly. The total number of openings contained in the braid or molded mesh forming the expandable basket (the total number of openings in the expandable basket) may be 12 to 1000, or 16 to 500, or 24 to 259, or 32 to 128.

[0124] Two or more filaments forming a braided or molded mesh, and thus an expandable basket, can be joined or bonded together at their proximal and / or distal ends, as schematically shown in Figure 21, to form a joined structure (2101) in the proximal and / or distal portions of the expandable basket. Such a solution can reduce the number of filaments in the proximal and / or distal portions of the expandable basket. Reducing the number of filaments entering related structures, such as the proximal portion of the expandable basket adjacent to the distal end of the outer elongated shaft, and / or the proximal portion of the basket assembly which may include attachments in the distal portion of the basket assembly which may include a terminal assembly, can reduce the complexity of those structures, and thus the entire basket assembly, and / or increase its mechanical stability. The reduced number of filaments may even help reduce the risks of the ablation procedure because the number of components in the structure is reduced. With respect to the length of the filaments, the joined structure at the proximal or distal portion of the filaments can occupy 1% to 30%, or 3% to 20%, or 5% to 15%, of the total length of the filaments contained in the expandable basket. As mentioned above, filaments can be joined at their distal or proximal ends, or both. When filaments are joined at both ends, the length of the joined portion may be the same at both ends or may be different. With respect to the length of the expandable basket of the folded configuration, the joined portion of the filaments at either the proximal or distal end of the basket may occupy 1% to 35%, 4% to 25%, or 6% to 20% of the length of the folded basket. Filaments can be joined, for example, by bonding, welding, lamination, binding, or melting. Another option is to join the filaments together, for example, by some kind of tubular structure or by crimping. The tubular structure may be, for example, a tube made of metal or polymer, or a thermoplastic tube with a lumen. In this case, the ends of the filaments are passed through the lumen of the tube and fixed therein (for example, by bonding, welding, lamination, binding, melting, or swaging), and thus joined to each other.Another option is the use of a multi-lumen tube made of metal, polymer, or thermoplastic resin, where each end of each filament to be joined is passed through a separate (its own) lumen of the multi-lumen tube and fixed therein (e.g., by bonding, welding, lamination, bonding, binding, melting, or swaging), and thus joined together as a single unit.

[0125] In an example having filaments (415) manufactured by a molding process such as injection molding, at least two filaments (415) can be molded as a single filament, braided into a braided 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 of the joined structures (either proximal or distal) can already be formed during the molding process. An example of filaments (415) and joined structures (2101) made by a molding process can be seen in Figure 26. The filaments (415) containing the already molded joined structures (2101) can then be braided into a braided mesh, thus avoiding at least one step of joining the filaments after braiding. The ends of the filaments (415) that have not yet been joined from the molding process can be joined together and / or joined with other different filaments after the braiding process.

[0126] The filament may be made from an electrically insulating nonconductive material, such as nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or a polymer or thermoplastic elastomer such as silicon. The material may be further reinforced with, for example, glass fibers. The cross-section of the filament may be circular, or other cross-sectional shapes are possible, such as elliptical, circular, semicircular, rectangular, square, flat, or star-shaped. The filament (415) may be formed from a tube having a structure that is at least partially hollow with a lumen (601), as seen, for example, in Figure 6B. Part or all of the filament (415) may be hollow along its entire length, or, for example, the lumen (601) may be present only in part of the length of one or more filaments (415). Another embodiment may include a braided mesh (413) comprising a first subset of filaments (415) having lumens (601) and another subset of filaments (415) not having lumens, or not all of the filaments have lumens.

[0127] In another example, the filament may be manufactured by a molding process, such as injection molding. Electrodes (109), such as conductive wires (417) connected to electrodes (109), and / or other components (e.g., tubes for generating lumens, reinforcing struts (2702), other wires, etc.) may be pre-positioned in the mold (2701) before molding, or they may be overmolded during the molding of the filament, as shown in Figure 27. Components can be completely overmolded, meaning they do not reach the surface of the filament (are not exposed on the surface of the filament), are completely inside the molded filament, and / or they can be partially overmolded, for example, if at least a portion of their surfaces is exposed on the surface of the filament. For example, electrodes can be partially overmolded when at least a portion of their surfaces is exposed on the surface of the molded filament. However, structures do not need to be overmolded, and at least a portion of them can be added to the filament, and therefore later to the braided mesh, after the filament molding process.

[0128] Filaments made from electrically insulated tubes with a hollow structure (cavity) may have drawbacks, for example, when an electrode in the form of a tube is placed on the filament and a wire coupled to the electrode is guided inside the lumen of the filament. Small openings in the wall of the filament usually facilitate the movement of the wire through the wall of the filament. These small openings need to be sealed to prevent, for example, blood or other fluids from reaching the inside of the filament. If the electrode is a ring-shaped electrode placed around the filament, the sealing may be between the filament and the electrode. Usually, such sealing is done by an adhesive placed in the area between the edge of the electrode and the filament on which the electrode is placed. The adhesive ensures a seal between the electrode and the filament. Another advantage of such a solution is that the adhesive on the edge of the electrode adds rigidity to the filament immediately adjacent to the electrode, ensuring that if the filament needs to bend in the area where the electrode is placed, the filament bends further away from the edge of the electrode, preventing exposure of the electrode edge. Electrodes can have sharp edges, and exposing such sharp edges can cause harm to, for example, the patient. A drawback of the solution using a ring-shaped electrode placed on a tubular filament and sealed with adhesive is that the sealing adds an additional material, which means the diameter of the filament increases where the adhesive is applied, and this can be problematic for catheters with a large number of filaments. Another problem with the solution of applying adhesive to seal the electrode from the filament is that the adhesive may peel off, which can result in some of the adhesive becoming loose and potentially harming the patient. This problem can be solved, for example, by filaments manufactured by a molding process, or in further examples, by filaments, for example.

[0129] In another example, the filament (415) may take the form of a structure that is at least partially hollow, including a tube made of a non-conductive material such as a thermoplastic resin. Exemplary cross-sections of such a filament (415) can be seen in Figures 31a-31c. The filament (415) including an electrode (109), for example a ring electrode, may include at least two tubes (3100) that can be joined to each other at the location where the electrode (109) is placed on the filament (415). The tubes (3100) may be made of a material with a melting point, for example a material having a melting point lower than the melting point of the other structure of the filament, for example a thermoplastic. The joint of the tubes may include a molten material (3101) that can originate from at least one of the tubes (3100). The molten material (3101) can fill the lumen of the electrode (109) and seal the electrode, and / or the conductive wire (417) coupled to the electrode, or another structure leading from the lumen of the filament to the electrode (109), or any other structure leading to the lumen of the filament, ensuring the connection between the tubes. The filament may include a cord (3102) which may be arranged longitudinally inside the lumen of the filament and may allow for uninterrupted passage in the region where at least the electrode (109) is located on the filament (415) and thus the tubes (3100) are connected to each other. The cord (3102) may serve as reinforcement for the filament.

[0130] The filament manufacturing process, which includes at least two tubes as described in the previous paragraph, may include the steps shown in Figures 31a and 31c. In the first step shown in Figure 31a, the tube (3100) and electrode (109) are placed on the cord (3102), with the electrode (109) positioned between the tubes, thus creating an assembly. A conductive wire (417) coupled to the electrode (109) is led into the lumen of one of the tubes (3100). In the next step, the entire assembly is heated to at least the melting temperature of the material from which the tube (3100) is made. The tube (3100) melts, and the molten material from the end of the tube adjacent to the electrode flows into the lumen of the electrode, filling it. In the next step, the assembly is cooled to at least a temperature lower than the melting temperature of the material from which the tube (3100) is made. The result of this step can be seen in Figures 31b and / or 31c.

[0131] The exemplary filament (415) shown in Figures 31a-31c may include other structures, in particular at least one ring (3103). The ring may be made of a different material from the tube (3100), in particular the melting point of the material of the ring (3103) may be higher than that of the material of the tube (3100), and the flex point of the material of the ring (3103) may be approximately the same as that of the material of the tube (3100). The ring may be placed on the tube, in particular at the end of the tube adjacent to the electrode (109). It can function as an additional sealing element, surface smoothing element, and reinforcing element at the transition between the edge of the electrode (107) and the tube (3001). This can prevent overflow of the tube material on the electrode during the manufacturing process. The ring can also assist the bending point of the filament. If the filament is bent, it can help move the bending point away from the electrode at the sharpest angle, which can be beneficial, for example, to prevent exposure of the sharp edge of the electrode. The ring length L may be 0.1mm to 10mm, or 0.2mm to 5mm, or 0.5mm to 4mm, or 0.7mm to 2.5mm. The filament may include one ring adjacent to one side of the electrode, or it may include, for example, at least two rings adjacent to both sides of the electrode.

[0132] The inner diameter of the rings (3103) before the manufacturing process may be the same as, or larger than, the outer diameter of the tubes (3100) they have before the manufacturing process. In the first step of the manufacturing process, as shown in Figure 31a, the rings (3103) can be placed on the tubes (3100), particularly at the end of the tube adjacent to the electrode (109), and the tubes (3100) with the electrode (109) are placed on the cord (3102) so that the electrode (109) is placed between the tubes (3100) with the rings (3103) to thus form an assembly. In the next step, the entire assembly is heated to at least the melting temperature of the material from which the tubes (3100) are made and the bending temperature of the material from which the rings (3103) are made. The tubes (3100) melt, and the molten material from the end of the tube adjacent to the electrode flows into and fills the lumen of the electrode, while the rings (3103) contract. The softened ring (3103) should shrink until its outer diameter reaches the same size as the outer diameter of electrode (109), or between the same size as the outer diameter of electrode (109) and 10% of the outer diameter of electrode (109), or between 0.1% of the outer diameter of electrode (109) and 7% of the outer diameter of electrode (109), or between 0.2% of the outer diameter of electrode (109) and 5% of the outer diameter of electrode (109). Such shrinkage can prevent the material from which the ring (3103) is formed from from melting on the electrode in a subsequent step, which could lead to potential insulation problems or delamination of such molten material on the electrode during use. The result of the step can be seen in Figure 31b. In the next step, the assembly is further heated to the melting temperature of the material from which the ring (3103) is formed. As shown in Figure 31c, the material of the ring (3103) melts and bonds with the material of the tube (3100). In the next step, the assembly is cooled at least below the melting temperature of the material from which the tube (3100) is fabricated.

[0133] Due to the shrinkage of the molten material of the tube (3100) and due to a portion of the tube material filling the lumen of the electrode during the manufacturing process, the outer diameter of the tube (3100) before the manufacturing process is obtained to be larger than the outer diameter of the electrode. This may be, for example, 1% to 60%, or 3% to 50%, or 5% to 40%, or 10% to 35% higher. The materials of the tube (3100) and the ring (3103) may be, for example, thermoplastic resins having two different melting temperatures, such as nylon. The materials may be selected such that the melting point of the ring (3103) material is higher than that of the tube (3100) material, and the deflection point of the ring (3103) material is approximately the same as that of the tube (3100) material.

[0134] The diameter of the filaments in the braided or molded mesh may be 0.2 mm to 1 mm, or 0.4 mm to 0.8 mm, or 0.5 mm to 0.7 mm. The number of filaments braided into the braided mesh forming the expandable basket may vary from 5 to 150, or 10 to 60, or 15 to 50, or 16 to 32. Filaments produced by the molding process may have several specific characteristics. For example, the diameter of a filament does not have to be uniform over its entire length and may vary along its length. For example, a filament may have a different (e.g., reduced) diameter in at least one intersection region compared to the rest of the filament. In a particular example of the intersection of two filaments, at least one of the filaments forming this intersection may have a reduced diameter in the intersection region and / or adjacent diameter and / or cross-sectional region involved in this intersection. In the example, if the diameter of a filament is reduced in a particular region, it may be reduced by, for example, 0.1% to 90%, or 0.5% to 75%, or 1% to 60%, compared to the diameter of the filament that is not reduced. In cases where the cross-sectional area is reduced in a specific region, the reduction may be by an amount ranging from 0.1% to 90%, 0.5% to 75%, or 1% to 60% compared to the unreduced cross-sectional area.

[0135] The reduction in the intersection area and / or adjacent filaments can help mechanically stabilize the braided mesh, and therefore the expandable basket, by providing more stable intersections, and / or help reduce the maximum diameter of the folded expandable basket. Reduced diameter filaments in the intersection area and / or adjacent filaments can ensure that the filament intersections remain relatively stable with respect to the length of the filaments while the basket assembly (expandable basket) expands and folds. This means that the filament intersections remain relatively the same over long distances of filaments in both the folded and fully expanded states of the basket assembly (expandable basket). What is changing is the relative angles of the particular filaments forming the intersection (e.g., from about 2 degrees to 178 degrees, or vice versa). Some kind of small longitudinal movement of the intersections cannot be completely avoided, but is within limits that do not impair the dimensions and / or mechanical stability of the braided mesh. This feature, then, can make it possible, for example, to place electrodes at the filament intersections and / or ensure the stable, predictable, and desired relative positions of the electrodes and / or their relative distances.

[0136] In another embodiment, filaments manufactured by a molding process may have variable cross-sectional shapes. This may be advantageous, for example, at filament intersections, where at least one different cross-sectional shape of the filaments included in the intersection may help stabilize the intersection and / or help reduce the maximum diameter of the expandable basket in a folded configuration. The cross-sectional shapes used in and / or adjacent to the intersection region of the filaments included in the filament intersection may be, for example, semicircular, rectangular, flat, elliptical or, for example, oblong, while the remaining cross-sections of the filaments may be different, for example, circular. If the cross-section of the filaments in and / or adjacent to the intersection region includes a flat or flat side, the flat or flat side may be in contact with the other filaments forming the intersection.

[0137] Combinations of variable cross-sectional area and variable diameter of the filaments are also possible. For example, the filaments may have different cross-sections and different (e.g., reduced) diameters in and / or adjacent to the intersection region, which can also facilitate the stabilization of the braided mesh, and thus the expandable basket, and the reduction of the maximum diameter of the expandable basket in the folded configuration. The maximum diameter of the expandable basket in the folded configuration may be reduced by, for example, 0.01% to 50%, or 0.05% to 30%, or 0.1% to 15%.

[0138] Variable diameter and / or variable cross-section can be used not only in and / or adjacent to the filament intersection region, but also in different regions of the filament. For example, a decrease in diameter and / or a change in cross-section can create weaker and / or stiffer regions of the filament, such as creating a living hinge during the filament molding process.

[0139] In another example, the molded filament does not need to be molded straight, but it can be pre-fabricated having at least one bend or curve (2601). The bend and / or curve (2601) may be located, for example, at at least one intersection region of the filament and / or adjacent thereto, or adjacent to, for example, the proximal or distal end of the filament. An example of such a solution is seen in Figure 26. The pre-formed curve (2601) can, for example, serve to further stabilize the braided mesh, and thus the expandable basket. The filament may be pre-formed so that thermal stabilization of the braided mesh after braiding is not required.

[0140] In a further embodiment, the filament can be molded to include at least one region in which the filament is divided, and / or at least one region in which an additional loop (2201) on the filament (415) is formed during the molding process. Such at least one divided region and / or additional loop (2201) may be formed, for example, in and / or adjacent to at least one filament intersection region (2202), and may also function, for example, as a support (fixing) at at least one intersection of two filaments (415) after the filaments (415) have been braided into a braided mesh. In a further example, the filament may include electrodes inside the division (e.g., inside the region bounded by the start and end of the filament division) and / or inside the filament loop region (2203), as seen in Figure 22.

[0141] A filament intersection region is a region in a filament that is involved in an intersection in a braided mesh structure. In some cases, at least one electrode may be located in and / or adjacent to a filament intersection region. If an electrode is located in and / or adjacent to the intersection region of a first filament included in a particular intersection, a second filament included in this intersection may not have an electrode in and / or adjacent to the intersection region of this particular intersection. This means that there may be at most one electrode at any intersection of the braided mesh, and therefore the expandable basket. In a further embodiment where an intersection includes an electrode, it may also be included in and / or adjacent to the intersection region of a filament further laterally from the longitudinal axis at this particular intersection, meaning that the electrode is located on the outer perimeter of the expandable basket.

[0142] In the example relating to a molded filament, such a molded filament may have a different diameter and / or cross-section in at least one intersection region from the rest of the filament, as already described. In one particular example, if an electrode is included in the intersection, the first filament containing the electrode may have a cross-section corresponding to the cross-section of the electrode in the intersection region (e.g., a circular cross-section), and may include the intersection region or an adjacent loop, and the second filament at this intersection may have a shorter diameter and / or a different cross-section than the rest of the filament (e.g., it may have a flat, rectangular, elliptical, or semicircular cross-section in the intersection region and a circular cross-section in another region).

[0143] However, this does not mean that a filament having electrodes in or adjacent to an intersection region cannot have a different diameter or cross-section from the rest of the filament in the intersection region. For example, electrodes included on a filament can have a different diameter or cross-section from the rest of the filament.

[0144] There are further options for increasing the mechanical stability of the filament. The use of multilayer walls can be one of them. The filament wall can, for example, include two or more layers of material. Materials with different properties can be used and combined to produce a more mechanically stable wall, and therefore a more mechanically stable filament. Such combinations can use layers made from different materials, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or polymers or thermoplastic resins from, for example, silicon. Another possible option is to use layers from the same type of material, but which may be different subgroups of materials with different properties for each layer. The material used for a particular layer can be further reinforced, for example, with glass fibers.

[0145] In another embodiment, the filament may be further mechanically reinforced, for example, by inserting a mechanical support into the lumen of the filament. Such a mechanical support may be, for example, in the form of a strut placed in the lumen of the filament. The strut may be placed inside the entire length of the filament, or inside the entire length of the lumen of the filament if the filament does not have a lumen along its entire length. Another possible option is to place the strut only in a portion of the entire length of the lumen, thus reinforcing a portion of the filament with the strut and leaving the other portion without strut reinforcement. The strut may be made of, for example, nitinol, or an electrical insulating layer, for example, polyamide (PA), polyimide (PI), or PTFE. Other possible materials suitable for the strut may be, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or polymers or thermoplastic resins from, for example, silicon.

[0146] In the 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 from a material having a higher melting point than the filament. At least one strut (2702) may be placed again along the entire length of the filament or only a portion of the length of the filament, so that a portion of the filament is reinforced with the strut and another portion is not reinforced with the strut. An example of a strut already placed in the mold can be seen in Figure 27.

[0147] Another option suitable for further reinforcing the filament is to fill at least a portion of the filament's lumen with an adhesive, molten polymer, or thermoplastic material.

[0148] Next, the braided mesh may be configured such that all of the filaments contained in the braided mesh are reinforced, or that only some of the filaments contained in the braided mesh contain the reinforcing material, while other parts of the filaments do not contain the reinforcing material.

[0149] At least one of the filaments forming the braided mesh may include at least one location where the structure of the filament is locally mechanically weaker than the rest of the filament. Such a location may form a so-called living hinge (2103), schematically shown in Figure 21. The living hinge may be useful in defining a more or less precise location where the filament contained in the braided mesh, and therefore contained in the expandable basket, bends more easily, and the bend in the filament forms a smaller radius (or direct kink) compared to a filament without such a living hinge. This may further help in defining a more predictable shape of the expandable basket when unfolded at at least one of the unfolding positions. Establishing such a living hinge in a filament may include thinning or cutting a portion of the filament. Thinning can be done, for example, by compressing or thermoforming a particular location of the filament. Thinning may be done all around the filament or only partially. Thinning in a partially asymmetrical manner may be advantageous, as it may define a particular direction in which the filament bends more easily than in other directions. In one example of an expandable basket, living hinges formed in the filaments can allow the filaments, and thus the braided mesh, to be easily bent radially from, for example, the longitudinal central axis of a catheter. For example, living hinges that create a small radius or twist in the filaments in the distal body portion (421) of the basket assembly body or in the region of the terminal assembly can help shape the expandable basket (basket assembly body) in the region located distal to the plane intersecting the basket assembly at the portion having the largest diameter (in one of its expansion configurations), so that at least a portion of the distal portion (region of the distal body portion) of the expandable basket can form a larger angle (radially from the elongated axis) compared to the proximal portion (region of the proximal body portion) of the basket.In extreme cases, the distal portion of the expandable basket (the distal body portion) forms an angle of 90° or more (radially from the elongated axis), so that at least a portion of the expandable basket containing the electrodes becomes the most distal part of the catheter in the longitudinal direction, and the expanded state can be achieved without any other portion (e.g., the terminal assembly) protruding further distally. Such a configuration may be advantageous, for example, in ablation of a relatively flat treatment site.

[0150] In examples where the expandable basket is formed from a molded mesh, or includes a filament formed by a molding process, living hinges can be formed directly during the molding of the molded mesh or filament, for example, by a reduction in the diameter of a portion of the molded mesh or filament, and at least one of a change in the cross-sectional area of ​​a portion of the molded mesh or filament.

[0151] As described in the previous paragraph, at least one living hinge may be included in at least part of the braided mesh, and the filaments are joined together (in the joined structure). In this case, the living hinge is a location on the joined structure, locally mechanically weaker than the rest of the joined structure, and can be made, for example, by thinning or cutting the joined structure after joining. In particular, if the joined structure includes polymer tubes and the filaments are joined into the lumens of the tubes or into multiple lumens of a multi-lumen tube, another option for establishing living hinges in the joined structure is to pre-thin or pre-cut the polymer tubes before inserting the filaments. Such pre-thinning of tubes can be done, for example, by compression, thermoforming, or molding, for example, injection molding.

[0152] Living hinges can be formed in the distal body portion, central body portion, and / or proximal body portion of the basket assembly body. They may be located in the proximal region, for example, 0% to 20%, 0% to 15%, or 0% to 10% of the folded basket length, if they are in the proximal body portion region. They may be located in the distal region, for example, 0% to 20%, 0% to 15%, or 0% to 10% of the folded basket length, if they are in the distal body portion region. They may also be part of the terminal assembly. If the hinge is located in the central body portion, it may be located on a plane intersecting the basket assembly, or distal to this plane or from the center of the folded basket, in the portion corresponding to the maximum diameter or -20% to +20%, -10% to +10%, or -5% to +5%.

[0153] An expandable basket may include one or more electrodes or a set of electrodes. An electrode may be configured to generate an electric field for tissue ablation, or to acquire or transmit electrical signals or other signals, such as tissue mapping, ECG monitoring, impedance measurement, and / or detection of contact with tissue, for at least one of these purposes. Another function of an electrode may be to act as an X-ray marker. Electrodes may be coupled to specific filaments of the expandable basket. Electrodes may be placed on each filament, or only on a portion of a filament. Each filament containing electrodes may include one or more electrodes, for example, 1 to 15, or 1 to 10, or 1 to 6, or 1 to 3 electrodes. Electrodes may be of one type or different types. The total number of electrodes placed on the expandable basket may be 1 to 200, or 5 to 100, or 10 to 50, or 15 to 40, or 20 to 35. The spatial distance between electrodes in the fully expanded configuration of the expandable basket may be 0.1 mm to 15 mm, or 0.5 mm to 10 mm, or 1 mm to 6 mm, or 2 mm to 4 mm.

[0154] The electrodes may operate individually, in pairs, or in groups, or some electrodes may operate individually while others operate in pairs or in groups.

[0155] In the example, electrodes may be positioned in the region where the filaments intersect each other (filament intersection). Such a position may be advantageous for its ability to maintain a more stable distance between electrodes in different configurations of the expandable basket, and such a configuration can also advantageously prevent undesirable contact between electrodes, especially when the expandable basket is not in a fully expanded configuration.

[0156] All electrodes in the expandable basket may be placed at the filament intersection, or only some of the electrodes may be placed at the filament intersection and some of the electrodes may be placed elsewhere.

[0157] Each filament may also contain one 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 and measuring electrodes, or physically different electrodes having different shapes, sizes, designs, materials, etc., or combinations of types of electrodes having different functional and physical properties. For example, in a configuration having ring-shaped electrodes arranged on a filament, all electrodes may have the same diameter and may have different lengths, so there may be, for example, two or more groups of such electrodes, each group having a different length. The number of electrodes in each group may be the same or different. In an extreme example, each electrode in an expandable basket may have a different length. In a configuration having ring-shaped electrodes, such electrodes may have a diameter of 0.2 mm to 3 mm, or 0.4 mm to 2 mm, or 0.5 mm to 1 mm, and a length of 0.1 mm to 10 mm, or 0.2 mm to 8 mm, or 0.3 mm to 6 mm, or 0.4 mm to 4 mm.

[0158] For example, there may be a first group of 5 to 20 shorter electrodes, for example, having a length of 0.3 mm to 3 mm, and a second group of 5 to 30 electrodes, which may be longer, for example, having a length of 0.6 mm to 4 mm. Advantageously, electrodes from the first group may be used for at least one type of measurement, e.g., intracardiac ECG (EGM) measurement, or ablation, and electrodes from the second group may be used for ablation, independently or in combination with electrodes from the first group.

[0159] Electrodes can be positioned on the body of the basket assembly. For example, electrodes may be positioned on the central or distal body portion, and in some cases, even on the proximal body portion. Other electrodes may be positioned on the surface or inside the outer elongated shaft, inner elongated shaft, distal tip of the catheter, or terminal assembly. In configurations where electrodes are positioned on the elongated shaft, distal tip, or terminal assembly and ring-shaped electrodes are used, they can have diameters of 0.2mm to 10mm, or 0.5mm to 8mm, or 1mm to 6mm, or 2mm to 5mm, and lengths of 0.1mm to 20mm, or 0.2mm to 15mm, or 0.3mm to 12mm, or 0.4mm to 10mm.

[0160] The electrode layout of the expandable basket can ensure a continuous, for example, circular ablation area while the expandable basket is in the expanded position, and can create a pattern.

[0161] For example, the electrode layout of the expandable basket can ensure a continuous circular ablation region and pattern can be fabricated, even while the expandable basket is held in various expanded positions between the fully folded and fully expanded positions.

[0162] Additional electrodes, such as external elongated shafts, internal elongated shafts, or those positioned on or inside the distal tip or terminal assembly of the catheter, may be part of the pattern or may be operated independently of other electrodes. For example, electrodes in the distal tip or terminal assembly region of the catheter can be used for punctate ablation. There may be special dedicated electrodes in the distal tip or terminal assembly region, or metal components of the terminal assembly may function as electrodes, or a combination of these may be possible.

[0163] The pattern (701) generated by the electrode (109) may be, for example, a circular pattern in space around the longitudinal central axis (203) when the expandable basket (409) is in one of its expansion configurations, as can be seen in at least Figure 7A. Other two-dimensional or three-dimensional patterns generated by the electrode (109) are also possible. The pattern (701) may or may not be centered around the longitudinal central axis (203). The pattern (701) may have different shapes, including but not limited to circles, ellipses, squares, rectangles, polygons, and planes, or the arrangement of the electrodes (109) in the expandable basket may be irregular. For example, there may be one pattern (701) in one plane, or more patterns (701) in one plane, or more patterns (701) in different planes.

[0164] The pattern generated by the electrode can be positioned on the basket assembly body, particularly on the distal, central, or proximal body portions, as shown in Figure 7B. The pattern may extend to two or more of these portions. For example, for the treatment of a flat treatment site located distal to the basket assembly, the electrode pattern may be favorably positioned on the distal portion of the basket assembly. In particular, the pattern may be positioned on a portion of the basket assembly enclosed by a region that forms an angle (703) from 0° to 90° with respect to the central axis (203) at the center of a plane (425) that intersects the basket assembly at the portion with the largest diameter (in one of the extended configurations). In some configurations, the pattern may be positioned partially on the distal portion of the basket assembly body and partially on the central portion of the basket assembly body. In some configurations, the pattern may be positioned on a section of the basket assembly enclosed by a region that forms an angle (705) from 0° to 120° with respect to the central axis (203) at the center of the plane (425). Such a pattern arrangement may be particularly advantageous for the treatment of vascular openings, such as pulmonary vein ossiceps. When the treatment site has a tubular shape, the pattern may be placed in the middle portion of the basket assembly, particularly in the portion of the basket assembly bounded by a region forming an angle (707) of 45° to 135° with respect to the central axis (203) at the center of the plane (425). When a flat treatment site is placed proximal to the basket assembly, for example, the septum, the electrode pattern may be placed in the proximal body portion of the basket assembly, or partially in the proximal body portion and partially in the central body portion, particularly in the portion of the basket assembly bounded by a region forming an angle (709) of 90° to 180° with respect to the central axis (203) at the center of the plane (425). Optionally, electrodes can be placed in all portions of the basket assembly, and thus patterns can be created in all portions, allowing for the selection of only the necessary or optimal patterns to perform a particular treatment.

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

[0166] The electrodes are electrically connected to the pulse generator, for example, by conductive wires. The electrodes may be electrically or communicatively connected to other units or parts of the pulse field ablation apparatus, as well as to, for example, 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. Apart from the ring-shaped electrodes described above, the electrodes may have any of many different shapes, e.g., a tube passed around a filament, a coiled metal sheet, a square and / or rectangle, or any other shape of conductive material attached to a filament. Another possible form of the electrode (109) may be an elongated continuous electrode drawn along a portion of the surface of the filament (415) so as not to contact the intersection of the filament (415) of the braided mesh (413), as shown in Figure 8. The electrode (109) may be attached to a particular filament (415) of the expandable basket by any means, e.g., mechanical mounting, swegging, crimping, bonding, lamination, deposition and / or soldering. Electrodes can be made from any conductive material, such as copper, gold, steel, titanium, platinum, or platinum-iridium. If there is at least one filament made from a conductive material, it can also function as an electrode. If the entire conductive filament is not insulated, the entire filament may function as an electrode, or if the filament is, for example, partially electrically insulated, the bare, uninsulated portion may function as an electrode.

[0167] Conductive wires can provide an electrical connection between the electrodes and the pulse generator. Conductive wires may be part of the structure of the basket assembly (401). For example, conductive wires (417) may be at least partially arranged in the lumen (601) of the filament (415), as shown in Figure 6C or Figure 9. One or more conductive wires (417) may be coupled to each electrode, or one or more electrodes may be coupled to a single lead wire. Conductive wires (417) may be incorporated into one of the walls of the shaft assembly, for example, the wall of the outer elongated shaft. Conductive wires may also be arranged in the central lumen of the outer elongated shaft, or a separate lumen may be present in the outer elongated shaft suitable for the arrangement of conductive wires. Conductive wires may be terminated adjacent to the electrodes, or they may extend spatially further along the length of the filament beyond the electrodes. Conductive wires may be arranged along the entire length of the filament of the basket assembly, for example. Optionally, some of the conductive wires (417) can be terminated adjacent to the electrodes, others can be spatially led further along the filament beyond the electrodes, or can be arranged along the entire length of the filament in the basket assembly.

[0168] When the conductive wire is arranged along the entire length of the filament, a design solution for expandable baskets in which the filament is not cut but bent at the distal end of the expandable basket and returned to the basket is particularly advantageous. Since certain conductive wires are configured to carry electrical pulses between electrodes and pulse generators, insulating the cut filament from the internal conductive wire is extremely difficult in the terminal assembly. On the other hand, in examples with bent filaments that have a conductor inside, insulation of the terminal assembly can be easily ensured.

[0169] The material used for conductive wires may be any conductive material, such as copper, stainless steel, steel, nitrile, aluminum, gold, platinum, or silver. Conductors may or may not be insulated. Wires may be insulated using any suitable material, such as different fluoropolymers, such as polyimide, polyurethane, polyester, polyvinyl chloride (PVC), rubber, rubber-like polymers, nylon, polyethylene, polypropylene, silicone, glass fiber, ethylene propylene diene monomer (EPDM), or polytetrafluoroethylene (PTFE). Wires may be made of a single conductor or a group of conductors, but wires made of a group of conductors are sometimes called "cables." If the wire is insulated, the minimum dielectric breakdown voltage of the wire insulator should be at least 100V, or 500V, or 1000V, or 4000V, or 10000V. The diameter of a wire with insulation may be limited by the dimensions of other structures of the device, such as a filament, and the minimum voltage that must be able to be held without risk of failure. With or without insulation, typical wire diameters can be between 0.05 mm and 0.7 mm, or between 0.07 mm and 0.5 mm, or between 0.1 mm and 0.3 mm, or between 0.11 mm and 0.2 mm, or between 0.12 mm and 0.18 mm.

[0170] Constructing a braided mesh from an electrically insulating material, such as one or more conductive wires within a hollow filament as described herein, may be particularly advantageous for ablation systems based on the principle of pulsed field ablation by a pulsed electric field. As will be further described, the pulsed field ablation method requires an electric field generated around an electrode. To generate the field, an electric pulse must be carried by a specific conductive wire between the electrode and the pulse generator. If the filament is nonconductive and the conductive wire is held inside the filament as described herein, even a voltage level of several kV, e.g., 1kV to 10kV, carried by the conductive wire can ensure the electrical insulation of the specific conductive wire. However, an option of a braided mesh having at least one or more filaments made from a conductive material (e.g., nitinol, copper, stainless steel, steel, aluminum, gold, platinum, or silver) may also be possible. Such conductive filaments may be insulated, uninsulated, or only partially insulated. They can not only potentially conduct current, but can also act as electrodes (if uninsulated or only partially insulated) and / or as further mechanical supports for the braided mesh, and thus for the expandable basket.

[0171] Another advantage of braided mesh made from polymer or thermoplastic elastomer filaments is that it is easier to manufacture compared to, for example, metal braided mesh. Braided mesh can be fabricated, for example, using a three-dimensional mandrel apparatus. The specific filaments forming the braided mesh can be arranged on the mandrel in a desired pattern. The filaments may already contain conductive wires. The entire structure can then be heated, for example, near the melting point of the filament material, and then the structure can be rapidly cooled. Since filaments made from thermoplastic elastomers or polymers generally require lower temperatures to reach their melting point than most metals, the manufacturing process can be faster and more efficient, and the required energy input may be less. Another advantage of such a manufacturing process is that the conductors do not need to be heated to extreme temperatures to the point where the electrical properties of the wires may be impaired. This situation can occur, for example, when the braided mesh is made from metal wires (metal filaments) and the braided mesh wires (filaments) also function as conductive wires.

[0172] Braided mesh with inserted conductive wires can be attached to outer and inner elongated shafts to form part of an expandable basket and basket assembly. Electrodes can be attached to specific filaments of the braided mesh before or after attaching the braided mesh to the elongated shafts. The pulse generator is the part that generates the electrical signal for the catheter electrode. The pulse generator can, for example, allow setting the amplitude during activation, the shape of the electrical pulse, and / or the number of pulses. The pulse generator can also diagnose the electrical waveform to measure power. The pulse generator can enable synchronous operation with an ECG device or an ablation system or another part of the device.

[0173] Furthermore, a method of ablation using the described pulse field ablation apparatus is disclosed.

[0174] One method includes the step of positioning a catheter (105) adjacent to the patient's treatment site, for example, a cardiac chamber, via a blood vessel. The catheter (105) may be inserted percutaneously into the patient's blood vessel.

[0175] Other support structures and / or devices can be used to help navigate the distal tip of the catheter to its desired position. Examples of such devices include guidewires or sheaths. The distal tip of the catheter may be delivered proximal to the treatment site in a folded state, for example, via a sheath. In the folded state, the diameter of the basket assembly at the distal tip of the catheter may be smaller than or approximately equal to the diameter of the outer elongated shaft of the catheter. Such a configuration allows for easy access to the distal tip of the catheter proximal to the treatment site.

[0176] The treatment site may be located inside the body, for example, inside or on the surface of the heart, for example, inside the cardiac chambers, and in particular, for example, inside the left atrium of the heart. The treatment site may include, for example, the pulmonary vein opening. Other locations of the treatment site may be, for example, any tubular tissue, organ or blood vessel in the body, or for example, a tumor site.

[0177] When the distal tip of the catheter is delivered to the treatment site, the catheter's basket assembly unfolds from a folded or semi-folded configuration to one of an extended configurations. This unfolding may be caused by the shape of the pretension of the braided mesh or its filaments, or by the linear displacement of the inner elongated shaft relative to the outer elongated shaft along the longitudinal central axis of the catheter, or by the tension of additional support structures, such as an inner coil or balloon (not shown), or a combination thereof.

[0178] Next, the distal tip of the catheter (107) may be positioned adjacent to the target tissue of the treatment site (1001), for example, on at least a portion of the basket assembly (401), and / or a portion of the expandable basket (409) may be in contact with the treatment site (1001). In this position, at least a portion of the pair of electrodes (109) positioned on the basket assembly (401) may be in contact with the tissue of the treatment site (1001). A schematic diagram of an exemplary position can be seen in Figure 10. The terminal assembly (411) can improve contact between the electrodes and the treatment site by having a flat design without distally protruding structures. When the basket assembly (401), particularly the distal portion of the basket assembly (405), has no distally protruding structures, it is easier to bring the electrodes into contact with the treatment site, even when the treatment site is relatively flat.

[0179] After positioning the distal tip of the catheter adjacent to the treatment site, any measurement steps can be performed with or without the catheter. For example, various types of measurements can be performed for the purpose of diagnosing the type or quality of tissue in or around the treatment site, determining the spatial position of the distal tip of the catheter, particularly its spatial position relative to the treatment site, determining contact between the distal tip of the catheter and / or a specific electrode and the target tissue at the treatment site, or understanding the electrophysiological processes of tissue adjacent to the electrode. For example, the electrode can also be used to measure contact with the target tissue and can be placed in an expandable basket, such as a braided mesh filament. The measurement electrode may be a different electrode from the ablation electrode, or the ablation electrode may be used for measurement. It is also possible to combine a separate measurement electrode with an ablation electrode having measurement capabilities at one of the distal tips of the catheter. To perform the measurement step, separate measuring devices can be used, such as a separate measuring catheter (not shown), an ECG device including an ECG trigger circuit, an ECG recording device, an ECG electrode, an intracardiac ECG (EGM), an intracardiac echocardiogram, an esophageal temperature measuring device, a fluoroscopy device, an RTG device, an MR device, etc. The measurement step may be performed once or may be repeated several times during the ablation procedure.

[0180] Ablation of the target tissue at the treatment site (1001) is performed using, for example, the principle of pulsed field ablation, which is induced by a pulsed electric field of appropriate parameters. The terms “electric field” or “pulsed electric field” are used herein, but the electric field as intended herein may further include a magnetic component.

[0181] The procedures for unfolding, measuring, and ablating the basket assembly can be carried out in several stages. For example, the expandable basket may be delivered adjacent to the treatment site in a fully folded configuration. After delivery, it can be unfolded into a first expanded configuration. For example, the pretension shape of the braided mesh and / or filaments can cause this first transition. In this configuration, further manipulation of the basket assembly, as well as measurement and / or ablation, can be performed. Further repositioning, measurement, and / or ablation can also be performed at this location in any order.

[0182] Next, the basket assembly can be deployed into a second extended configuration. This second extended configuration can be achieved, for example, by linear displacement of the inner elongated shaft relative to the outer elongated shaft along the longitudinal central axis of the catheter. In this configuration, for example, further manipulation of the basket assembly, as well as measurement and / or ablation, can be performed. Further repositioning, measurement, and / or ablation can also be performed in any order at this position.

[0183] The basket assembly can be deployed to several different expanded positions, for example, during which further repositioning, measurement, and / or ablation can be performed.

[0184] In pulmonary vein isolation ablation, a set of electrodes can create a circular shape around the pulmonary vein orifice. After ablation, the shape of the ablated tissue may have a circular shape around the pulmonary vein orifice. Several such shapes of ablated tissue can be created by rearranging the basket assembly or by switching between different electrodes.

[0185] A pulsed electric field (PEF) is generated, for example, by an electrical pulse, such as a high-frequency electrical pulse. The electrical pulse can be generated by a pulse generator and delivered to the target tissue in the form of a pulsed electric field (PEF) by an electrode that can be placed at the distal tip of a catheter and electrically contact the pulse generator. Electrical pulses can be generated by a wide variety of pulses, ranging from single-phase (single-polarity) pulses to symmetrical and / or asymmetrical two-phase pulses. The pulse may be combined with an extra pre-pulse or extra measurement pulse for tissue conditioning. The pulse may be a single pulse or may be repeated in a sequence, remaining constant even as the pulse parameters change. A sequence of pulses can also be executed in sequence. The maximum amplitude of the pulse depends on the target tissue, electrode size, and / or electrode distance, for example, to generate an electric field with a maximum electric field intensity of 0.1kV to 10kV or 0.4kV to 5kV or 0.5kV to 2kV per centimeter of target tissue volume. The pulse duration can range from nanoseconds to milliseconds, for example, 2ns to 10ms, or 10ns to 5ms, or 10μs to 1ms. The pulse shape may be, for example, a square, a curve similar to exponential discharge, a rectangle, a sawtooth, a triangle, or a sinusoidal waveform.

[0186] A pulse can be monophase or biphase. A biphase pulse can be symmetrical or asymmetrical. A pulse can be repeated from 1 to 100,000 times. The frequency of a high-frequency pulse can vary from 0.1 Hz to 10 Hz. The amplitude (Um) of a single-phase pulse can vary from 100 V to 10 kV, and the peak-to-peak amplitude of a biphase pulse can vary from 200 V to 20 kV.

[0187] Figure 16 can serve as an example of possible parts of a pulsed field ablation (PFA) protocol and as a clarification of terminology and expressions related to 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 specific hierarchies, such as sequences (TR) and bursts (B).

[0188] An electrical pulse (1601) can be defined, for example, by its shape, amplitude (Um) at a particular voltage, and pulse length at a duration (t1). The pulse amplitude (Um) can be either negative or positive in the case of a single-phase pulse (a pulse can have a negative or positive voltage). Electrical pulses (1601) can be separated from each other by inter-pulse pauses (1603) defined by their duration (t2) and voltage (Up). The voltage during the inter-pulse pause (1603) may drop to 0V or may have a positive or negative voltage value (Up). The absolute voltage value (Up) of the inter-pulse pause is smaller than the absolute voltage (amplitude (Um)) of the adjacent electrical pulse (1601), and in particular, up to 50% of the amplitude (Um) of the adjacent electrical pulse. When the electrical pulse has a positive amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) remains positive between 0V and the amplitude (Um) of the electrical pulse (1601). When the electrical pulse (1601) has a negative amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) remains negative between 0V and the amplitude (Um) of the electrical pulse. An example of an inter-pulse pause (1603) with a voltage different from 0V is shown in Figure 17a. The two-phase pulse may be symmetrical or asymmetrical in at least one of time, amplitude, or energy.

[0189] An example of a two-phase electrical pulse is shown in Figure 17b. A two-phase pulse can have the same amplitude (voltage) for both the positive phase (1701) and the negative phase (1703) with the same duration (t10, t12) for both phases (exemplary pulses A, D), or the amplitude and / or duration (t10) of the positive phase and the amplitude and / or duration (t12) of the negative phase may differ (exemplary pulses B, C). The resulting pulse may then have the same energy in the positive and negative phases of the pulse, or the energies of the positive and negative phases of the pulse may differ. A two-phase pulse with the same energy in both phases is sometimes called a symmetric two-phase pulse. A symmetric two-phase pulse may be balanced (if the duration and amplitude of both phases of the pulse are the same) or unbalanced (if the amplitude and / or duration differ in each phase). An asymmetric two-phase pulse has phases with different energies. Exemplary two-phase pulses A, B, and C have no pauses between specific phases of the pulse (interphase pauses), while exemplary pulse D is a two-phase pulse with an interphase pause (1705). The duration of the interphase pause in the pulse can be 0 μs to 50 μs, or 0 μs to 10 μs, or 0 μs to 5 μs.

[0190] A set or series of consecutive pulses, with or without inter-pulse pauses, may be called a column (TR). A particular column (TR) may be characterized, for example, by duration (t4) or number of pulses, separated from each other by inter-column pauses (1607) having duration (t5), or inter-column pauses (1607) may separate columns having individual single pulses. A set or series of columns (TR) and inter-column pauses (1607) may be called a burst (B), which may be characterized, for example, by duration (t6), number of columns (TR), number of pulses, or inter-burst pauses (1615) (having a duration (t7) between a particular burst (B)).

[0191] As already mentioned above, the voltage value (Up) at the electrodes does not necessarily have to decrease to 0V between pulses, especially during interpulse pauses (1603), but may remain at a level of up to 50% of the amplitude (Um) of the adjacent electrical pulse, for example, where there is no or very little risk of generating bubbles due to electrolysis or temperature rise. This may also reduce the undesirable relaxation of polar molecules, potentially shortening the length of at least some parts of the PFA protocol and thus potentially increasing the effectiveness of PEF therapy.

[0192] When pulses with amplitudes (Um) of several hundred to several thousand volts are applied, even if applied to the atria, there is a certain risk of causing ventricular muscle depolarization and undesirable ventricular rhythms in the heart. Depolarization can be caused by the electric field or directly by another device placed in or near the atria, ventricles, or both, such as secondary energy leads in a catheter. Setting the timing of the active sequence (individual pulses, columns, and / or bursts) with pauses, as described below, has an effect called overdrive. The overdrive effect is commonly used in ablation catheterization to mitigate the risk of undesirable rhythms by using an external pacemaker. The advantage of the proposed PFA protocol is that, since the therapeutic (ablation) electrical pulses can also act as pace-stimulating pulses to the heart if they cause myocardial depolarization, there is no need to use an additional pacing device (e.g., an external pacemaker) to synchronize the pacing device pulses with the therapeutic pulses of the PFA protocol. This means that, in this case, it is not necessary to use a pacing device to control the number of ventricular contractions per minute, detect individual ventricular contractions from a surface ECG, and then trigger pulses for ablation accordingly.

[0193] The duration (t8) of one cycle (1609) of a burst (B), and the inter-burst pause (1615) between bursts, which is between 201 ms and 800 ms, are given by the range between the need to deliver pulses safely faster than the patient's actual heart rate (overdrive effect) and the need to maintain the heart rate at a safe level (generally stated to be 220 beats / min minus age). The cycle duration may be fixed or variable within the specified range (201 ms to 800 ms) in the PFA protocol, for example, according to a sine or trigonometric function. Individual bursts (B) may have a duration (t6) of 1 ms to 200 ms, or 30 ms to 180 ms, or 60 ms to 160 ms, which is a safe time for the burst (B) of the applied pulse to contract the cardiac chambers and protect the ventricles from damage or undesirable rhythms. The burst (B) duration (t6) can also be fixed or variable within the range specified in the PFA protocol (1ms to 200ms), for example, according to a sine or trigonometric function.

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

[0195] However, while electroporation is described as the primary trigger for cardiomyocyte death after PEF application, actual cell death may instead be caused by, for example, electrical disruption of the membranes of cardiomyocytes, mitochondria, or the nucleus; by separating individual cardiomyocytes / cardiomyomyocytes (or groups of cells) of the cardiomyocyte (e.g., by direct electric field or mechanical damage due to hypercontraction, by damaging or destroying the intercalated disk); by damage to myofibromas or myofibrils of muscle fibers; by ATP depletion and insufficient production in cardiomyocytes due to hypercontraction; by loosening the intercellular junctions of cardiomyocytes; by myolysis of muscle cells; by directly wrinkling cardiomyocytes under the influence of an electric field or by mechanical damage due to hypercontraction; by irreversible damage to the calcium cycle (whether due to the sarcoplasmic reticulum or ion pumps or calcium channels or calcium-binding proteins); by calcium overload of the cardiomyocytes - mitochondrial swelling (as a result of hypercontraction or damage to the cardiomyocyte fascia or nonphysiological 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 generated between one or more electrodes positioned at the distal tip of the catheter and a single unrelated electrode positioned at a distance, for example, on the patient's skin. In some embodiments, the unrelated electrode may have a surface area significantly larger than the sum of the surfaces of the active distal tip electrodes. This mode of operation is usually called unipolar. Another option for generating an electric field is the bipolar mode. In this mode, an electric field is generated between two or more distal tip electrodes, usually positioned close together or adjacent, that have different polarities. In this case, the sum of the surfaces of the active electrodes with the first polarity is equal to the sum of the surfaces of the active electrodes with the second polarity.

[0197] In some embodiments, the electrode (109) positioned in the distal assembly can operate in a hybrid mode of the two preceding types. An example of such an embodiment is shown in Figure 11. In this mode, only the electrode (109) positioned at the distal tip (107) is used for ablation. There exists a first single electrode, or a group of electrodes operating in a mode having a first polarity (P1), and a second single electrode, or a group of electrodes operating in a mode having a polarity different from the operating mode of the first electrode, or group of electrodes (P2, which may be the opposite polarity). The surface or total surface area of ​​the first electrode, or the first group of electrodes, is significantly smaller than the surface or total surface area of ​​the second electrode, or group of electrodes. For example, there may be a third group of electrodes operating in a third mode under high impedance (HI) conditions, where the impedance of the third group of electrodes is, for example, higher than 500 Ω. The electrode operating in the third mode may be adjacent to the electrode, or group of electrodes operating in the first mode.

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

[0199] Figure 12 shows a modified example of a hybrid operating mode for an electrode (109) having a group of electrodes (two or more electrodes) operating in a mode having a first polarity (P1). The functional principle of this operating mode is similar to that of the modified example in which one electrode (109) operates in a mode having the first polarity (P1). For example, the total surface area of ​​the electrodes operating in a mode having the first polarity (P1) is significantly smaller than the total surface area of ​​the electrodes operating in a mode having a different polarity (P2).

[0200] An example of a group of electrodes (two or more electrodes) operating in a mode with a first polarity (P1) may be more advantageous than an example of a single electrode operating in a mode with a first polarity (P1), for example, in situations where reducing the size of the electrodes is advantageous. Reducing the size of the electrodes may be advantageous or necessary when increasing the number of electrodes is necessary or desirable. For example, a larger number of electrodes is desirable when more accurate mapping of the treatment site or more accurate and / or uniform ablation of the target tissue at the treatment site is desired. Since the treatment site may be part of the human anatomical structure, the overall size of the pulsed-field ablation device, especially the catheter with a distal tip, must be limited according to the human anatomical structure. Therefore, if more electrodes are needed in the ablation device, for a given number of electrodes, the size of the electrodes must be limited so as to fit the limited dimensions of the important parts of the pulsed-field ablation device, e.g., the catheter and / or its distal tip, and / or its basket assembly. Another advantage of smaller electrode sizes is that such a configuration may help increase the depth of ablation.

[0201] Smaller electrodes can offer other advantages; for example, in cases where the same electrode is used for ablation and measurement, it means the same electrode must be configured to deliver high-voltage pulses and record measurements. For instance, smaller electrodes may be advantageous in measuring ECG signals.

[0202] However, there are also some challenges associated with smaller electrodes. In examples involving pulsed field ablation, the electric field is generated between electrodes, for example, by an electrical pulse, such as a high-frequency electrical pulse generated by a pulse generator. For effective ablation of the entire target area of ​​the treatment site, it may be important to generate an electric field with a maximum amplitude of several hundred to several kilovolts per centimeter with respect to the target tissue volume. Using smaller electrodes means a smaller electrode surface area. When the electrode surface area is smaller, the voltage induced on the electrode must be higher compared to a larger electrode with a larger surface area in order to achieve the desired electric field density in the target tissue. Adverse effects of such a configuration may include a higher density electric field, a higher intensity electric field, and / or the possibility of sparks occurring at the edges of the electrodes. However, some or all of these problems can be addressed and overcome by using a group of selected electrodes (two or more electrodes) operating in a first polarity mode instead of a single electrode operating in a first polarity mode. With respect to a first group of well-selected electrodes operating in a mode with a first polarity, a second group of electrodes operating in a mode with a different polarity, and a third group of electrodes operating in a third mode, possibly in a high-impedance state, the first group of electrodes and / or the second group of electrodes can function as virtual electrodes. That is, the electrodes of the first group can act together as one virtual electrode, and / or the electrodes of the second group can act as another virtual electrode. Such a configuration can reduce the intensity and / or density of the electric field near the electrodes. Other positive effects of this configuration may include a reduced risk of sparking and an increased depth of ablation, or an increased depth of ablated tissue at the treatment site.

[0203] An increase in the surface area of ​​the first group of electrodes, and the resulting creation of a virtual electrode, can lead to a decrease in the voltage that needs to be induced in the electrode, and / or the elimination of sparks, primarily at the edges of the electrode. However, the concept of disproportionate surface areas of the electrodes in the first and second groups of electrodes can be preserved, meaning that the surface area or total surface area of ​​the first electrode or the first group of electrodes is significantly smaller than the surface area or total surface area of ​​the second electrode or the group of electrodes. The ratio of the surface area of ​​the first group of electrodes or the total surface area of ​​the electrodes to the total surface area of ​​the second group of electrodes can be 2:3 to 1:100, or 3:5 to 1:80, or 3:5 to 1:70, or 1:2 to 1:50, or 1:2 to 1:40, or 1:2 to 1:30, or 1:2 to 1:20, or 1:3 to 1:15, or 1:3 to 1:10, or 1:4 to 1:8.

[0204] Adding electrodes to a first group of electrodes operating in a first polarity mode can significantly reduce the electric field strength near the electrodes. For example, using four electrodes instead of one in a first group of electrodes operating in a first polarity mode reduces the electric field strength at the electrode surface by a quarter, while using three electrodes reduces the electric field strength by half. This reduction in strength may allow the use of lower voltages for the electrodes compared to a solution with only one electrode operating in a first polarity mode. In addition to this, or instead, the reduction can increase the depth of the ablated target tissue by increasing the area of ​​the electric field at a constant voltage per centimeter. The voltage values ​​per centimeter in the area of ​​the electric field can be, for example, 50 V / cm to 3000 V / cm, or 100 V / cm to 1500 V / cm, or 250 V / cm to 1000 V / cm.

[0205] Specific electrodes at the distal tip of the catheter can be switched to one or more modes during ablation. They can be switched during a single ablation cycle or during several ablation cycles. The electrodes may be switched to one or more modes several times during a single ablation cycle or during several ablation cycles. In some embodiments, it is even possible to have a group of two or more electrodes operating simultaneously in a mode having a first polarity, and a group of electrodes operating in different polarities, with or without an electrode 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 pulse train, before or after one or more pulse trains in a pulse train, or before or after one or more bursts of pulses.

[0207] The electrode layout or spatial pattern at the distal tip can be fabricated to take into account the hybrid operating modes of the electrode and / or for the purpose of fabricating a virtual electrode. Since the electrode can be switched to one or more modes during ablation, the resulting virtual electrode can have different spatial shapes, which means that the electric fields generated around and between the virtual electrode can have different shapes with magnetic fields of different structures and / or electric fields of different densities and intensities. Examples of electrode spatial patterns at the distal tip, specifically in an expandable basket, can be seen in Figures 13A and 13B. Figure 13A shows a front view of a basket assembly (401) having an electrode (109) spatial pattern suitable for fabricating a virtual electrode by switching the electrode (109) to different operating modes in a first polarity and different polarities and / or high impedance states.

[0208] Figure 13B again shows a front view of a basket assembly (401) having an electrode spatial pattern suitable for fabricating a virtual electrode by switching the electrode (109) to a different mode, but this time the electrode is positioned in the region where the filaments (415) intersect each other (filament intersection).

[0209] An example of a possible electrode layout already switched to hybrid operating mode is shown in Figure 14, also a front view of the basket assembly (401). A first group of electrodes (109) are operating in a mode with a first polarity (P1) and together form a first virtual electrode (1401). Another group of electrodes (109) are operating in a mode with a different polarity (P2) and together form a second virtual electrode (1403). In this configuration, when an electrical pulse is delivered from the pulse generator (103) to the electrodes (109), an electric field is generated between and around the virtual electrodes (1401, 1403). Some of the electrodes (109) may be operating in a third mode, for example, in a high impedance (HI) state.

[0210] Electrodes in a high impedance state (higher than 500 Ω) can help shape the electric field generated between and around electrodes from a first group of electrodes and a second group of electrodes, and / or between or around virtual electrodes. For example, assigning a high impedance state to an electrode spatially adjacent to an electrode operating in a first polarity mode can have a positive effect on the shape of the electric field, allowing a portion of the electric field capable of causing ablation to reach deeper into the target tissue at the treatment site, compared to an operating mode without an electrode in the high impedance state. This phenomenon can have a positive effect on the quality and uniformity of the ablation procedure. Electrodes in a high impedance state can be spatially positioned between the first group of electrodes and the second group of electrodes.

[0211] An exemplary pattern of electrode (109) is shown in more detail in Figure 15A. Electrode (109) creates a repeating cross, square, or rectangular pattern on the filament (415) of the braided mesh in one of the expansion configurations of the expandable basket. From this figure perpendicular to the tangent plane (for example, in contact with the expandable basket at the intersection (1501) of four adjacent electrodes), the pattern appears two-dimensional, but is actually three-dimensional because electrode (109) is fixed to or part of the filament (415) of the braided mesh, forming the expandable basket, and therefore the pattern conforms to the curvature of the expandable basket. This pattern of electrodes is advantageous in embodiments using a group of electrodes operating in a mode having a first polarity (P1). In this example, the group of four adjacent electrodes operating in a mode having a first polarity (P1) and thus creating a first virtual electrode (1401) has either a cross shape as shown in Figure 15A, or a square or rectangle as shown in Figure 15B. The advantage is that both virtual electrodes (1401) generated by both shapes, when combined with a second virtual electrode, can, in some cases, be prompted by the electrode being in a high-impedance state, generate an electric field with specific qualities (potential shape, magnitude, density, gradient) suitable for ablation of target tissue.

[0212] Figure 15C shows an example of an electrode pattern in which electrodes (109) are positioned in regions where filaments (415) intersect with each other (filament intersections). A group of exemplary electrodes operating in a mode having a first polarity (P1) is also shown here.

[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 the group of electrodes forming the virtual electrode may differ in the folded configuration and / or different expanded configurations of the expandable basket. In most expanded configurations of the expandable basket, the rectangles and squares formed by the electrodes as described above are tilted to form shapes closer to rhombuses or oblong rectangles. The same is true for the angle between the two virtual lines that form a cross and pass through the electrodes, which is not a right angle in most expanded configurations.

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

[0215] When using high-voltage pulses in the human body, for safety reasons, such as to avoid ventricular rhythms, it may be necessary to synchronize the pulse delivery with the cardiac cycle. Pulse field ablation devices may incorporate or use means for such synchronization, including a trigger for pulse delivery by this synchronization means. The synchronization means may be, for example, an ECG device.

Claims

1. An ablation apparatus comprising a generator configured to generate electrical pulses having an amplitude of 100V to 5000V and coupled to at least one electrode, wherein the generator is Power supply unit, Capacitor unit, and The capacitor unit and the electrode are connected to a DC / DC converter unit, The DC / DC converter unit comprises an output capacitor and an output capacitor emergency system, wherein the output capacitor emergency system is configured to discharge the output capacitor when activated and to cut off voltage delivery from the generator to the electrode within 50 ms after activation, in an ablation device.

2. The ablation apparatus according to claim 1, wherein the output capacitor emergency system comprises a safety discharge resistor configured to discharge the output capacitor within 50 ms after startup.

3. The ablation apparatus according to claim 2, wherein the output capacitor emergency system includes one of a thyristor or a contactor, the thyristor or the contactor being configured to short-circuit the output capacitor.

4. The ablation apparatus according to claim 1, further comprising an electrical control circuit configured to receive and evaluate data from the ablation apparatus including at least one parameter to be measured, and to activate the output capacitor emergency system to discharge the output capacitor and interrupt voltage delivery from the generator to the electrode when at least one of the parameters to be measured is outside a predetermined boundary.

5. The ablation apparatus according to claim 4, wherein the parameter to be measured is one of temperature, impedance, current, or voltage.

6. An ablation apparatus for pulsed field ablation, wherein the ablation apparatus includes a generator configured to generate electrical pulses and coupled to at least one electrode, the generator is Power supply unit, Capacitor unit, and A DC / DC converter unit including an output capacitor, wherein the DC / DC converter unit is coupled between the capacitor unit and the electrode, and Equipped with an output capacitor emergency system, The output capacitor emergency system is configured, when activated, to discharge the output capacitor and interrupt voltage delivery from the generator to the electrode, an ablation device.

7. The ablation apparatus according to claim 6, wherein the output capacitor emergency system includes a safety discharge resistor configured to discharge the output capacitor.

8. The ablation apparatus according to claim 6, wherein the output capacitor emergency system includes one of a thyristor or a contactor, the thyristor or the contactor being configured to short-circuit the output capacitor.

9. The ablation apparatus according to claim 6, wherein the output capacitor emergency system is configured to discharge the output capacitor and to interrupt voltage delivery from the generator to the electrode within 50 ms after activation of the output capacitor emergency system.

10. The ablation apparatus according to claim 6, further comprising a switching unit, wherein the DC / DC converter unit is coupled between the capacitor unit and the switching unit.

11. The ablation apparatus according to claim 6, further comprising an electrical control circuit configured to receive and evaluate data including at least one parameter to be measured from the ablation apparatus, and further configured to activate the output capacitor emergency system when at least one of the parameters to be measured is outside a predetermined boundary.

12. A generator for an ablation apparatus configured to generate electrical pulses and coupled to at least one electrode, wherein the generator is Power supply unit, Capacitor unit, and Equipped with a DC / DC converter unit, The DC / DC converter unit comprises an output capacitor and an output capacitor emergency system, wherein the output capacitor emergency system is configured to discharge the output capacitor and interrupt voltage delivery from the generator to the electrodes when activated.

13. The generator according to claim 12, wherein the DC / DC converter unit includes a safety discharge resistor configured to discharge the output capacitor.

14. The generator according to claim 12, wherein the DC / DC converter unit includes one of a thyristor or a contactor, the thyristor or the contactor is configured to short-circuit the output capacitor.

15. The generator according to claim 12, wherein the output capacitor emergency system is configured to discharge the output capacitor when activated and to cut off the voltage delivery from the generator to the electrode within 50 ms after activation.

16. The generator according to claim 12, wherein the output capacitor has a capacitance of 1 μF to 200 μF.

17. The generator according to claim 12, wherein the DC / DC converter unit includes a DC / DC converter without feedback.

18. The generator according to claim 12, wherein the DC / DC converter unit is configured to convert the high capacitance of the capacitor unit to a lower capacitance with the output capacitor.

19. The generator according to claim 12, wherein the DC / DC converter unit is configured to limit the leakage current from the power supply unit to the patient to less than 10 μA.

20. The generator according to claim 12, wherein the DC / DC converter unit includes two windings and a series resonant converter.

21. The generator according to claim 12, wherein the DC / DC converter unit has a conversion ratio of 1:1 to 1:

6.

22. The generator according to claim 12, wherein the generator includes a switching unit, and the DC / DC converter unit is coupled between the capacitor unit and the switching unit.

23. The DC / DC converter unit has an input voltage of 100V to 5000V, as described in claim 12.

24. The DC / DC converter unit has an output voltage of 150V to 5000V, as described in claim 12.

25. A control method for an ablation apparatus for pulsed field ablation, wherein the method is (a) Providing an ablation apparatus comprising a generator and at least one electrode coupled to the generator, wherein the generator comprises a DC / DC converter unit comprising a power supply unit, a capacitor unit, an output capacitor and an output capacitor emergency system. (b) One or more electrical control circuits are provided coupled to at least one of the power supply unit, the capacitor unit, the DC / DC converter unit, the switching unit, and / or the current supply source. (c) Receiving data comprising at least one parameter to be measured via the one or more electrical control circuits, (d) Evaluating the data, (e) If the parameter to be measured is outside a predetermined boundary, activate the output capacitor emergency system to discharge the output capacitor and interrupt the voltage delivery from the generator to the electrode. A method that includes this.

26. The output capacitor emergency system includes a safety discharge resistor configured to discharge the output capacitor, The method according to claim 25, wherein activating the output capacitor emergency system includes discharging the output capacitor to the safety discharge resistor.

27. ​​The output capacitor emergency system includes at least one of a thyristor or a contactor configured to short-circuit the output capacitor, The method according to claim 25, wherein activating the output capacitor emergency system includes short-circuiting the output capacitor.

28. The method according to claim 25, wherein the parameter to be measured is one of temperature, impedance, current, or voltage.

29. The method according to claim 25, wherein the parameter to be measured is voltage, and the method further comprises the step of measuring the voltage at at least one output of the power supply unit, the capacitor unit, or the DC / DC converter unit.

30. The parameter being measured is voltage. A switching unit is provided in the generator, wherein the switching unit includes at least one switch, and The method according to claim 25, further comprising the step of measuring the voltage of at least one output of the switching unit or the switch.

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