Pulsed electric field ablation apparatus and methods

Abstract

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

Description

TECHNICAL FIELD

[0001] The present invention relates to ablation devices and methods, in particular to devices and methods for pulsed electric field ablation of a target tissue by means of a pulsed electric field, wherein one of the main principles of the ablation can be irreversible electroporation of cell membranes. BACKGROUND

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

[0003] Catheter ablation involves the advancement of one or more flexible catheters subcutaneously into a blood vessel of a patient, typically in the femoral vein, internal jugular vein or subclavian vein, in the case of cardiac ablation. The catheter is then advanced towards a target treatment site within or on the heart.

[0004] The main approach of arrhythmia ablation therapy is to directly eliminate pro-arrhythmic substrates by destroying them or to prevent the propagation of non-physiological action potentials by linear or circular isolation. Both approaches essentially require the formation of lesions through which the action potential of the myocardium does not spread. By applying energy, a small portion of the myocardium is locally destroyed and is transformed into non-myocardial connective tissue over a period of several weeks by natural physiological processes.

[0005] Common ablation methods known in the prior art are based on thermal destruction of tissue by high or low temperatures. Such methods include, for example, heating the target tissue by means of a radio frequency field (RF) or a laser, or freezing the tissue by means of cryoablation. These methods lead to necrosis of the target tissue, thereby increasing the risks of the procedure.

[0006] More recently, methods and devices for ablation using electric fields have been utilized. The goal of these methods is to cause tissue destruction by inducing irreversible electroporation of cell membranes rather than by thermal destruction by high or low temperatures, thereby reducing the disadvantages and risks of ablation procedures that are primarily based on thermal lesions, however, disadvantages remain that need to be addressed.

[0007] A common design of such devices can be a catheter with a distal tip having one or more electrodes. The catheter can have, for example, one active electrode on the tip. An indifferent electrode can be placed, for example, on the skin of the patient. Ablation of the target treatment site with such a device has to be done point by point, which increases the duration and complexity of the procedure.

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

[0009] Devices with a catheter tip basket comprising a single strut with electrodes are also known from the prior art. This device can ensure easier deployment and positioning with respect to the target site. Because there are usually more electrodes placed on the catheter tip, ablation can also be monopolar with irrelevant electrodes placed on the patient's skin, for example, or bipolar between specific electrodes on the catheter tip. One disadvantage of this solution is the limited number of struts, which means a limited number of electrodes forming a specific circular pattern in space. This disadvantage is due to the mechanical stability required for the specific struts in order to be able to maintain the stable shape of the basket. This means that the struts need to maintain a specific size in order to be sufficiently rigid. The number of struts used is limited by the size of the catheter. Another disadvantage of this solution is that this structure cannot fully guarantee the mutual distance of the struts in the deployed configuration, which means that the distance between the electrodes cannot be guaranteed either. This means that the device can require multiple repositioning to ensure correct ablation, thus prolonging the duration of the procedure.

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

[0011] Disclosed herein is a device and method of an ablation system, in particular an ablation method and device by electric field for pulsed electric field ablation according to the description, which can solve the above problems, is more gentle and safer for the patient, reduces time and technical complexity, and improves the quality, efficacy and reliability of the system, method and device itself. BRIEF DESCRIPTION OF DRAWINGS

[0012] One exemplary aspect of the present application is illustrated in the attached drawings by way of example, in which identical reference numerals indicate identical or similar elements, in which:

[0013] Figure 1 Block diagram of an exemplary ablation system.

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

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

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

[0017] Figure 4 An exemplary illustration of a catheter distal tip with a basket assembly in an expanded configuration.

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

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

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

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

[0022] Figure 7A An exemplary front view of a distal end of a catheter.

[0023] Figure 7B An exemplary side view of a distal end 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 wires inside the filament lumens is shown.

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

[0027] Figure 11 An exemplary illustration of an operating mode of the electrodes.

[0028] Figure 12 An exemplary illustration of another operating mode of the electrodes.

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

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

[0031] Figure 14Possible layout for electrodes that have switched to a hybrid mode of operation.

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

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

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

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

[0036] Figure 17a An example of an inter-pulse pause with a voltage different from 0 V is shown.

[0037] Figure 17b An example of different biphasic pulses is shown.

[0038] Figure 18 A view of one example of a terminal assembly.

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

[0040] Figure 20 An example of filaments that are connected together at their intersection points is shown.

[0041] Figure 21 A view of a distal portion of a basket assembly with a merged structure and active hinges.

[0042] Figure 22 An example of filaments made by a molding process is shown.

[0043] Figure 23 A view of an example of a partial braided mesh including filaments made by a molding process.

[0044] Figure 24a An example of a planar braided mesh made by a molding process.

[0045] Figure 24b A planar molded braided mesh bent into a tubular shape is shown.

[0046] Figure 24c A plurality of planar molded meshes bent into a tubular shape is shown.

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

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

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

[0050] Figure 27 An exemplary placement of components in a mold configured for injection molding of a filament is shown.

[0051] Figure 28 A cross section of an expandable basket secured to an inner elongated shaft is shown.

[0052] Figure 29 Is a view of an example of an inner elongated shaft end and expandable basket before and after mechanical attachment to each other.

[0053] Figure 30a Is a cross sectional view of an expandable basket secured to an inner elongated shaft.

[0054] Figure 30b A detailed view of an exemplary protrusion on an inner elongated shaft is shown.

[0055] Figure 31a A cross section of a filament in a manufacturing step is shown.

[0056] Figure 31b A cross section of a filament in another manufacturing step is shown.

[0057] Figure 31c Another cross section of a filament in another manufacturing step is shown.

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

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

[0060] Figure 34 A layout of electrodes imprinted in a two-dimensional plane is shown. DETAILED DESCRIPTION

[0061] Figure 1An ablation system (100) for pulsed electric field ablation of target tissue is illustrated. The ablation system (100) described herein includes a pulsed electric field ablation device (101). The ablation system (100) may include or be connected to other components or devices suitable for performing or supporting the pulsed electric field ablation method described herein. Other components or devices may be, for example, a control unit (111), a graphical user interface (GUI) unit (113), an electrical control circuit (115), an electrocardiogram (ECG) trigger circuit (117), an ECG recording device (129), ECG electrodes (125), a pacemaker (131), a catheter signal interconnection circuit (119), and / or an electrophysiological (EP) display device (133), which may include an EP recording system. The electrophysiological 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-position measurement (RPM) device, and / or an unrelated electrode (127). The mapping device (135) records an EGM (electrocardiogram) of the location in space, for example, measured via a catheter, and forms a mapping map of the surface of the heart. The location and orientation of the catheter may also be displayed. Other possible methods for measuring the real-position of the catheter may be via a sensor in the catheter (e.g., magnetically based position measurement) or, for example, using impedance measurement or radiofrequency-based measurement on the catheter electrodes, or a combination thereof. Advantageously, in some examples, the catheter used for position measurement is the same as the catheter used for ablation.

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

[0063] The generator (103) can be configured to generate high-voltage electrical pulses, for example, with frequencies ranging from 0.1 Hz to 10 Hz, single-phase pulse amplitudes varying from 100 V to 5 kV, and two-phase pulse peak-to-peak amplitudes varying from 200 V to 10 kV. The pulse duration can range from nanoseconds to milliseconds. Figure 32 An exemplary simplified schematic diagram of the generator (103) can be seen in the diagram.

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

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

[0066] The generator can further comprise a switching unit (3204), which can comprise, for example, at least one switch (3205), e.g. a semiconductor switch. An input of the switching unit (3204) can be coupled to the capacitor unit (3203), an output of the switching unit (3204), namely the switch (3205), can be coupled to the at least one electrode (109) and can be configured for switching the electrode (109) into the first polarity mode, the second polarity mode and the high impedance mode. The number of switches (3205) can depend on the number of individually switchable electrodes or groups of individually switchable electrodes (109). One switch (3205) can be coupled to one electrode (109) or more than one electrode.

[0067] The switch (3205) can be a semiconductor switch, e.g. an improved half bridge (3300). In Figure 33 A schematic of the improved half bridge (3300) can be seen in Fig. 33. The improved half bridge (3300) is an improvement of the conventional half bridge. The improved half bridge solves the problem of the parasitic behavior of the conventional half bridge, namely the leakage current in the closed state and the output capacitance. The improved half bridge (3300) can comprise a top side and a bottom side. The top transistor (3301) is coupled with a common collector. The top resistor (3302) is coupled to the emitter of the top transistor (3301) with ground. Due to the position of the top resistor (3302), in the closed state of the top transistor (3301) the voltage across the top resistor (3302) is close to zero. The improved half bridge (3300) can further comprise a top diode (3303). The top diode (3303) is coupled via its anode to the emitter of the top transistor (3301) and via its cathode to the output (OUT) of the half bridge (3300). In case of a closed top transistor (3301) (high impedance state) the top diode (3303) can ensure that no current from the output of the half bridge (3300) goes through the top resistor (3302). The bottom transistor (3304) has a common emitter and there is a bottom resistor (3305) coupled to the collector of the bottom transistor (3304). The bottom resistor (3305) is coupled to the positive supply (+). Due to the bottom resistor (3305), in the closed state of the bottom transistor (3304) the voltage across the bottom resistor (3305) is close to zero. The bottom diode (3306) is connected in reverse, i.e. 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 one example, when the switch unit (3204) is directly coupled to the capacitor unit (3203), the safety of the patient or the operator can depend on the reliability of the at least one switch (3205). In case of failure of the switch (3205), the patient or the operator can be exposed to the uncontrolled dissipation of the high capacitance of the capacitor unit (3203) in a duration of 50 ms to 100 ms.

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

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

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

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

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

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

[0075] Figure 2The illustrated catheter (105) includes a shaft assembly (201) and a catheter distal tip (107) located near a distal end of the catheter (105). The shaft assembly (201) defines a longitudinal center axis (203) of the catheter (105). The catheter (105) can also include a handle assembly (123) and a connection assembly (121). The catheter (105) can be steerable or non-steerable and can be introduced into its position, e.g., via a guide sheath (not shown) and with or without the help of a guide wire (not shown).

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

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

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

[0079] Figure 3A A catheter (105) with a shaft assembly (201) is shown. The shaft assembly can include an outer elongated shaft (303) and / or an inner elongated shaft (301). In Figure 3BThe cross-section of the exemplary shaft assembly (201) in the illustrated cross-section A-A can comprise 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 relative to each other in the longitudinal direction along the longitudinal center axis (203). Such translation can for example allow the expandable basket (409) to be deployed / retracted from a collapsed configuration to a fully expanded configuration and back.

[0080] The outer elongated shaft can comprise a proximal end portion, a distal end portion and a main body extending between the proximal and distal end portions. The outer elongated shaft can be coupled to the handle assembly near its proximal end portion and to the catheter distal tip near its distal end portion.

[0081] The main body of the outer elongated shaft (303) can comprise one or more lumens (309, 311), for example, extending along the entire length between its proximal and distal end portions. The lumens can for example be adapted to guide wires or fluids, for example, irrigation fluids. The one or more lumens can be configured to receive one or more inner elongated shafts. The main body of the outer elongated shaft can for example be further defined by a proximal end portion (305) and an intermediate portion (307). The intermediate portion of the main body can be designed with a flexible sheath compared to the proximal end portion to allow bending and increase the flexibility of the outer elongated shaft. The proximal end portion for example comprises a stiffer material sheath to increase the torque and stiffness of the main body of the outer elongated shaft. Suitable materials for constructing the sheath include, but are not limited to, nylon, TPU, HDPE or PEBA.

[0082] The main body of the outer elongated shaft can comprise wires. The wires can pass through the central lumen (309) of the outer elongated shaft or the outer elongated shaft can comprise several other lumens (311) and thus one or more wires can pass through one or more of the other lumens (311). For example, the number of other lumens can match the number of braided mesh on the catheter distal tip, for example, if 20 filaments are used in the construction of the catheter distal tip, 20 other lumens can be used.

[0083] The wires can extend from the basket assembly to the connection assembly, for example, near the handle assembly.

[0084] In certain aspects, the inner elongated shaft can be configured to slide along the longitudinal center axis relative to the outer elongated shaft. Thus, the one or more lumens can for example comprise a low-friction lining, for example, a polytetrafluoroethylene (PTFE) lining.

[0085] Rigidity and torque are important features that the outer elongated shaft should have, and thus, the outer elongated shaft can include, for example, a braid of metal or rigid polymer wire wrapped around the inner layer of the body, which in some aspects is embedded within the outer jacket of the body, or can include a rigid polymer, including but not limited to polyimide, polyamide, polyether ether ketone (PEEK), or any other suitable material.

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

[0087] The outer diameter (OD) of the outer elongated shaft can be, for example, in accordance with the French catheter scale commonly used for catheter sizing. The scale in this scale defines diameters in Frenches (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 elongated shaft can be between 5 FR and 20 FR, or from 7 FR to 16 FR, or from 9 FR to 15 FR. The diameter of the central lumen of the outer elongated shaft can be approximately between 0.1 mm and 5 mm, or 1 mm to 4 mm, or 2 mm to 3.5 mm, or 2.5 mm to 3 mm.

[0088] The inner elongated shaft can include a proximal end, a distal end, and a body extending between the proximal end and the distal end. The body of the inner elongated shaft can include one or more lumens (313), for example, extending along the entire length between the proximal end and the distal end of the inner elongated shaft, or can be devoid of lumens. The one or more lumens (313) of the inner elongated shaft can be designed, for example, to accommodate standard guide wires (not shown) and / or to direct fluids, for example, flushing fluids. The diameter of the one or more lumens (313) can be from 0.1 mm to 3 mm, or from 0.5 mm to 1.5 mm, or from 0.9 mm to 1 mm, or from 0.94 mm to 0.99 mm. The one or more inner elongated shafts can be adapted to be placed in the one or more lumens (309, 311) of the outer elongated shaft. The dimensions of the inner elongated shaft can be selected to match the diameter of the designated lumen of the outer elongated shaft, but both structures still need to allow for their smooth relative translation. This means that the outer dimensions of the inner elongated shaft (301) can be from 0.1 mm to 4.9 mm, or from 0.5 mm to 3.5 mm, or from 1 mm to 3 mm, or from 1.28 mm to 2.8 mm.

[0089] As the inner elongated shaft can be adapted to house a guidewire within its lumen, a low-friction lining of the lumen can be used, e.g., a PTFE lining.

[0090] As the inner elongated shaft can be translated relative to the outer elongated shaft to deploy the basket assembly / expandable basket, a braid socket can be woven along the length of the PTFE lining, for example, to form the body of the inner elongated shaft. The other side can include a cut hypotube instead of a braid in the body of the inner elongated shaft to improve its flexibility and torque.

[0091] Above the layer with the braid or hypotube, a melt / laminate polymer jacket can be fused to enhance the flexibility of the tube and provide a seamless surface. A variety of polymers can be used for the jacket, with exemplary materials being nylon, polyether block amide (PEBA), polyether ether ketone (PEEK), or polyimide.

[0092] Figure 4 The distal tip (107) of the catheter of the illustrated example also includes a basket assembly (401). The basket assembly (401) can include a basket assembly proximal portion (403), a basket assembly distal portion (405), and a basket assembly body (407) extending between the proximal and distal portions. The basket assembly body can include a central body portion (419) that unfolds about a plane (425) that intersects the basket assembly in the portion of the basket assembly having the highest diameter in the proximal and distal directions (in one of its expanded configurations) occupying about 1 / 3 of the basket assembly body. The basket assembly body can also include a distal body portion (421) extending distally from the central body portion (419) and a proximal body portion (423) extending proximally from the central body portion (419), each of which occupies about 1 / 3 of the basket assembly body (407).

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

[0094] In Figure 28Examples of attachment of the distal portion of an expandable basket (409) adjacent to the distal end of one or more internal elongated shafts (301) can be found. In this particular example, the distal end of the expandable basket (409) may be formed by means of a ring (2801) to which a filament (415) is secured, or bent around the location (2804) where the filament (415) is secured to the 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 protrusions (2802, 2803) are formed on the internal elongated shaft 301 such that these two protrusions hold either side (proximal and distal) of the distal end of the basket, for example including the ring 2801 that locks the expandable basket (409) to the internal elongated shaft 301. Figure 29 As shown, the assembly is formed by pushing an internal elongated shaft (301) with a prepared first protrusion (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 protrusion (2802) on the shaft reaches the distal portion of the expandable basket from the proximal side. The end of the internal elongated shaft (2901) (the end of the internal elongated shaft protruding distally from the basket) is then tilted / heated on a bullet-shaped mold to form a second protrusion (2803) with a damage-resistant bullet-shaped end, which will prevent the internal elongated shaft (301) from moving proximally relative to the expandable basket (409). The connection is made in a manner that locks the internal elongated shaft (301) to the expandable basket (409) under operating conditions, but also in a manner that allows the connection to break and loosen under a certain axial load if the basket cannot be expanded and the catheter needs to be withdrawn from the patient. The axial load (force) required for the braking connection can range from 10N to 100N, or from 15N to 75N, or from 20N to 50N.

[0095] Protrusions (2802, 2803) can also be formed on the internal slender shaft using other techniques. Figure 30a and Figure 30bA particular example is shown in FIG. 28. In this example, the second protrusion (2803) can be formed by a distal add-on member (3001) coupled to the inner elongated shaft (301), e.g., to the inner elongated shaft end (2901). The distal add-on member (3001) can have the form of, e.g., a ring, a cylinder, a cone, a truncated cone, or a hollow tubular body, e.g., with an atraumatic shape (e.g., bullet-shaped, flange-shaped) formed at its distal end, e.g., to ensure that the terminal assembly does not mechanically harm the patient, and can be made of, e.g., plastic or metal. The distal add-on member 3001 can comprise a tubular structure (3002) protruding proximally from the second protrusion 2803 parallel to the inner elongated shaft. The distal add-on member (3001) and / or the tubular structure (3002) can comprise a cavity (3006) adapted to receive at least a portion of the inner elongated shaft (301), e.g., the inner elongated shaft end (2901) and the lead wires. The cavity (3006) can have two inner diameters, a first diameter (3007) formed proximally of the distal add-on member (3001) 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 distally from the first diameter (3007) smaller than the first diameter (3007) and smaller than the outer diameter of the inner elongated shaft (301), e.g., configured for the lead wires to pass through. With this configuration of the cavity (3006), the distal add-on member (3001) can serve as a distal stop for the inner elongated shaft (301) in the direction of the longitudinal central axis (203), while also preventing possible sharp edges of the inner elongated shaft end (2901) from being exposed distally of the distal add-on member (3001) and possible tissue damage caused by contact. The distal add-on member 3001 can be coupled to the inner elongated shaft 301, and the coupling can comprise, e.g., crimping, welding, screws, threads, molten plastic, or an adhesive, e.g., a hot-melt adhesive or glue.

[0096] In Figure 30a and Figure 30bIn the particular example shown, the distal add-on member (3001) can be coupled to the inner elongated shaft (301), e.g. by means of a molten plastic or an adhesive. The distal add-on member 3001 can comprise a cavity with a larger diameter than the outer diameter of the inner elongated shaft 301, e.g. 0.1% to 50% or 0.5% to 40% or 1% to 25% larger. The inner elongated shaft can be inserted into the cavity and the resulting space (3003) between the inner elongated shaft (301) and the cavity wall can be filled with an adhesive, e.g. a hot-melt adhesive or a glue. For this purpose, the distal add-on member 3001 can comprise a glue opening 3004 which can serve as an inlet for the adhesive into the resulting space 3003. After filling the glue into the resulting space (3003), the glue opening (3004) can be closed and sealed, e.g. by means of a plug, a molten plastic or by means of an adhesive, e.g. by means of a hot-melt adhesive or by means of a glue, possibly the same adhesive that was used to couple the distal add-on member (3001) to the inner elongated shaft (301).

[0097] As shown in the example in Figure 30a and Figure 30b , the first protrusion (2802) can be formed, e.g. by means of a tubular proximal add-on member (3005) which is coupled to the inner elongated shaft (301). The proximal add-on member (3005) can be directly coupled to the inner elongated shaft (301) or can be coupled to the inner elongated shaft (301), e.g. via the distal add-on member (3001), e.g. to the tubular structure (3002). In the example shown in Figure 30a and Figure 30b , the proximal add-on member 3005 can be coupled to the inner elongated shaft 301 directly and indirectly via the distal add-on member 3001. The coupling of the proximal add-on member (3005) to the inner elongated shaft (301) and / or to the distal add-on member (3001) can comprise, e.g. a crimping, a welding, a screw, a thread, a molten plastic, an adhesive (e.g. a hot-melt adhesive or a glue) or a further fixation member (not shown) which is placed, e.g. proximally of the inner elongated shaft (301). The first protrusion (2802) can have a form or can comprise, e.g. a plastic tube.

[0098] The loop (2801) to which the filaments (415) are fixed can be coupled to the inner elongated shaft (301) directly or, e.g. via the distal add-on member (3001) or the proximal add-on member (3005). Figure 30a and Figure 30b One example of a loop 2801 coupled to the inner elongated shaft 301 via the distal add-on member 3001 is shown in. In this particular example, the distal add-on member 3001 comprises a tubular structure 3002 which protrudes proximally from a second protrusion 2803 which is parallel to the inner elongated shaft and the loop 2801 can encircle the tubular structure 3002.

[0099] The terminal assembly (411) can advantageously be designed without or at least with reduced structures protruding in distal direction from the basket assembly distal portion (405), e.g. a cap or similar. This is particularly advantageous in case the at least partial ablation method needs to be performed at a relatively flat treatment site.

[0100] An exemplary solution for the terminal assembly can be an overmolded structure. The filaments can be fixed to each other and / or to the distal end of the inner elongated shaft by an overmold process, forming an overmolded terminal assembly. Another fixation process (and / or terminal assembly forming process) similar to overmolding can be e.g. flipping, where the filaments are at least partially melted and pressed into a preformed mold, thereby being connected together and / or to the inner elongated shaft. Laminating is another exemplary process to fix the filaments at their distal end to form a terminal assembly. The terminal assembly can also be formed by swaging or crimping the distal ends of the filaments. The filaments can be brought together in the terminal assembly area and swaged or crimped together by e.g. some kind of metal ring.

[0101] In another example, the terminal assembly can be formed as Figure 18The illustrated articulated mechanical structure. For example, one or more filaments may be located at their distal ends in the terminal assembly region fixed to the articulated element (1801), which includes, for example, a lateral narrow portion (1803) and a distal portion (1805) wider than the lateral narrow portion (1803). The lateral narrow portion (1803) may be in the form of a pin, for example, having a square, rectangular, circular, elliptical, or other suitable cross-section. The distal portion (1805) may be, for example, elliptical or circular, or in another example, spherical or ball-shaped. Other possible shapes of the distal portion (1805) may be cylindrical, conical, cubic, or block-shaped. For example, in cases where the entire articulated element (1801) is made of a single sheet of material (metal plate, polymer plate) or not (e.g., in the case of a cast or forged articulated element), it may have the same dimensions as the lateral narrow portion (1803). The hinge element 1801 can be made of, for example, metal (e.g., nitinol) or other materials (e.g., polymers or thermoplastics). The filament is secured to the hinge element by, for example, welding, gluing, or coiling. The area of ​​the connection (1807) can be, for example, at least partially laminated to prevent possible tissue damage and to seal the assembly. The hinge element is then secured in a central bullet structure (1809). This can be, for example, a hollow structure with a cut window (1811) adapted to accommodate the proximal portion (1803) of the hinge element (1801). In this case, the distal portion (1805) of the hinge element is placed in an inner cavity (1813) within the hollow structure. In some examples, the dimensions (cross-section or width) of the distal portion (1805) of the hinge element can be larger than the dimensions of the window (1811). This prevents the distal portion (1805) of the hinge element (1801) from sliding through the window (1811), thereby holding the hinge element together with the connecting area (1807) and the distal portion of the filament attached to the central bullet structure (1809). The central bullet structure (1809) may include several parts joined together (e.g., by welding, gluing or other mechanical means, such as snap-fit, thread, screw, bolt, etc.). It may also have different shapes, such as cylindrical, spherical or elliptical. The shape of the inner cavity (1813) may correspond to the outer shape or may be different. The central bullet structure may include a fixing member (1815) for securing the distal end of the inner elongated shaft to the central bullet structure. The fixing member (1815) may have the shape of, for example, a hollow tube connected to the central bullet structure. The fixing member is adapted to receive and / or connect the distal portion of the inner elongated shaft and may allow the flow and / or redirection of fluid, such as flushing fluid flowing out of the inner cavity of the inner elongated shaft. The fixed component may interfere with the internal cavity (1813) or may be mechanically and / or fluidly connected to the internal cavity. It may be adapted, for example, by means of... Figure 19The illustrated holes (1901) direct at least a portion of the flushing fluid into the interior lumen of the central bullet structure.

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

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

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

[0105] For example, the expandable basket (409) can be in Figure 5 The illustrated transition (deployment / retraction) between the collapsed configuration and one or more expanded configurations. The transition (deployment / retraction) can be caused by the pre-tensioned shape of the woven mesh (413) and / or the filaments (415) and / or by the linear displacement of the inner elongated shaft (301) along the longitudinal central axis (203) of the catheter (105) against the outer elongated shaft (303) or a combination thereof. Another possibility to deploy / retract the expandable basket (409) can be by tension of an additional support structure, for example, an inner coil or a balloon (not shown).

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

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

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

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

[0110] Further structural stability of an expandable basket made of a woven mesh can be achieved by connecting specific filaments (included in the woven mesh) together. The filaments can for example be connected together at their mutual intersection points. An exemplary solution can be as shown in Figure 20 The joint (2001) can be fixed (not allowing any mutual movement of the filaments in the joint point) or interactive (some mutual movement of the filaments in the joint point is possible). The connection can be achieved for example by gluing, welding, lamination, bonding, tying (for example with some kind of string) or melting. Another option can be to tie the filaments together for example by a loop structure or a crimp. In case the loop structure is made of an electrically conductive material (for example metal), it can also be used as an electrode. The same applies to the crimp. A metal connector can also be used as an electrode.

[0111] Even before weaving, structures suitable for connecting two filaments can already be included on the filaments. In an example where at least one filament (415) is made by a molding process (e.g., an injection molding process), the filament (415) can include at least one region that splits the filament and / or at least one region that will create an additional loop (2201) on the filament during the molding process, as can be seen in Figure 22 and Figure 23 Such at least one split region and / or additional loop (2201) can for example be formed at or near at least one filament intersection region (2202), which is the region where the filament intersects with another filament in a crossing point (2301) in the weaving grid. The split or loop (2201) on the first filament (415) included in the crossing point (2301) can be suitable for insertion into the second filament (415) included in the crossing point (2301), thereby serving to help connect (fix) the two filaments (415) together in the crossing point (2301). Such a crossing point (2301) where the filaments (415) are fixed by a loop (2201) or split can have similar properties as a crossing point that is connected e.g. by a knot made with a string, but without the need for a knotting step.

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

[0113] All crossing points included in the expandable basket can be connected, or only some of the crossing points can be connected, while the remaining crossing points can not be connected.

[0114] In another example, the expandable basket can be made by a molding process, e.g. by an injection molding process. In this example, the mesh of the expandable basket can not be woven, but can be made from a molded structure. There can be several options for how the expandable basket is manufactured by molding.

[0115] The expandable basket can be made for example from at least one molded net (flat molded net) in two dimensions (flat, planar) form (2401), as shown in Figure 24a The at least one flat molded net (2401) is configured to be shaped into a three-dimensional shape after molding. The at least one flat molded net can be taken out of the mold after molding and can be bent for example around a central longitudinal axis (203), for example into a tubular shape as shown in Figure 24b Figure 24c is an example where more than one flat molded net is used to form the expandable basket. In this example, each molded net (2401) can be bent into a shape that independently forms only a part of the intended tube (a circumferential part of the intended tube) and when combined together forms the entire tube. The edges (2402) of the molded nets will then be coupled together (for example by welding, crimping, gluing, knotting...) to form the tubular structure. Thereafter, the distal end portion (2403) of the tubular structure can be brought together and coupled together and possibly fixed to the distal end portion of the inner elongated shaft, thereby forming the terminal assembly and thus the expandable basket. The proximal end portion (2404) of the tubular structure can be coupled to the distal end of the outer elongated shaft.

[0116] In another example, the expandable basket can be made from a molded net that has been molded into a three-dimensional structure. Figure 25a An example of such a structure is shown, which can be for example a tubular molded net structure (2501). In this example, the step of bending the two-dimensional flat molded net can be omitted and the tubular molded net structure has been made in the mold. The further steps will be similar to the previous example. The distal end portion (2403) of the tubular molded net structure (2501) can be brought together and coupled together and possibly fixed to the distal end portion of the inner elongated shaft, thereby forming the terminal assembly and thus the expandable basket. The proximal end portion (2404) of the tubular molded net structure (2501) can be coupled to the distal end of the outer elongated shaft.

[0117] In Figure 25b another example shown in

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

[0119] The molded mesh molded into a three-dimensional structure does not have to be molded into the entire structure, but several three-dimensional parts of the molded mesh can be molded and then coupled together. For example, the three-dimensional parts can be formed independently only a part of the intended structure (e.g., a part of the circumference of a tube or basket in one of its expanded states), and form the entire structure when brought together and connected together.

[0120] In the example of the expandable basket made of a molded mesh, electrodes, wires and / or other structures (e.g., tubes for forming lumens, reinforcing struts, etc.) can be placed in the mold prior to molding and can be overmolded during the molding of the molded mesh. These structures can be fully overmolded, which means that these structures will be entirely inside the molded mesh without reaching the surface of the molded mesh, and / or partially, e.g., when at least a part of the surface of these structures is exposed on the surface of the molded mesh. For example, an electrode can be partially overmolded when at least a part of the surface of the electrode is exposed on the surface of the molded mesh. However, these structures do not have to be overmolded and at least a part of these structures can be added to the molded mesh after the molding process of the molded mesh.

[0121] The molded mesh can be made of a polymer or a thermoplastic elastomer, e.g., nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET) or e.g., silicon.

[0122] The specific openings (mesh, gaps) within the braided or molded mesh do not have to have a uniform size, but rather the size of the specific openings can vary. The size can for example increase from the distal and proximal portions of the expandable basket (where the size can be the smallest) towards the middle portion of the expandable basket (where the size can be the largest). In other words, the size of the openings in the central body portion of the basket assembly can be larger than the size of the openings in the proximal and distal body portions of the basket assembly. The size can for example increase linearly or exponentially. The circumference of the openings in the proximal and distal body portions can for example be between 1 mm and 40 mm, while the circumference of the openings in the central body portion can for example be between 5 mm and 80 mm. The number of rows of openings forming the complete braided or molded mesh of the expandable basket can be between 4 and 40.

[0123] The ratio of the circumference of the smallest opening to the circumference of the largest opening in the expandable basket can 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 full opening, which is counted from the connection of the proximal portion of the expandable basket adjacent to the distal end of the outer elongated shaft, to the last opening in the distal portion of the basket assembly terminated by the terminal assembly. The total number of openings included in the braided or molded mesh forming the expandable basket (total number of openings in the expandable basket) can be from 12 to 1000, or from 16 to 500, or from 24 to 259, or from 32 to 128.

[0124] The two or more filaments forming the braided or molded mesh and thus the expandable basket can be merged or connected together at their proximal and / or distal ends to form a merged structure (2101) in the proximal and / or distal portion of the expandable basket, as Figure 21 This solution can reduce the number of filaments in the proximal and / or distal portion of the expandable basket. Reducing the number of filaments entering the relevant structures (e.g., the proximal portion of the basket assembly and / or the distal portion of the basket assembly) can reduce the complexity and / or enhance the mechanical stability of these structures (and thus of the entire basket assembly), the proximal portion of the basket assembly can include the attachment of the proximal portion of the expandable basket adjacent to the distal end of the outer elongated shaft, and the distal portion of the basket assembly can include the terminal assembly. This can even help reduce the risk of the ablation procedure due to the reduction in the number of components in the structures with reduced number of filaments. In terms of filament length, the merged structure in the proximal or distal portion of the filament can occupy 1% to 30% or 3% to 20% or 5% to 15% of the total length of the filaments included in the expandable basket. As mentioned before, the filaments can be merged at the distal or proximal end of the filament or at both locations. In case the filaments are merged at both ends, the merged length can be the same or different at these two ends. Relative to the length of the expandable basket in the collapsed configuration, the merged portion of the filaments can occupy 1% to 35% or 4% to 25% or 6% to 20% of the length of the collapsed basket at the proximal or distal end of the basket. The filaments can be merged, for example, by gluing, welding, lamination, bonding, binding, or melting. Another option can be to connect the filaments together, for example, by some kind of tubular structure or by crimping. The tubular structure can be, for example, a tube made of metal or polymer or thermoplastic with an inner lumen. In this case, the ends of the filaments will pass through the inner lumen of the tube, be fixed there (e.g., by gluing, welding, lamination, bonding, binding, melting, or swaging) and thus be connected together. Another option can be to use a multi-lumen tube made of metal or polymer or thermoplastic, where each end of each filament to be connected will pass through a separate (its own) lumen of the multi-lumen tube, be fixed there (e.g., by gluing, welding, lamination, bonding, binding, melting, or swaging) and thus be connected together.

[0125] In an example having filaments (415) formed by a molding process (e.g., injection molding), at least two filaments (415) can be molded into single filaments, woven into a web, and then joined together at their proximal and / or distal ends to form a merged structure (2101). However, at least two filaments (415) can be molded at once, such that at least one merged structure (2101) (proximal or distal end) can already be formed in the molding process. Figure 26 An example of filaments (415) and merging structures (2101) produced by a molding process can be seen. The filaments (415), including the molded merging structure (2101), can then be woven into a web, avoiding at least one step of filament merging after weaving. After the weaving process, the ends of filaments (415) that were not merged in the molding process can be merged together and / or merged with other different filaments.

[0126] The filament may be made of an electrically insulating, non-conductive material, such as a polymer or thermoplastic elastomer, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET), or, for example, silicone. The material may be further reinforced, for example, by glass fiber. The cross-section of the filament may be circular, or other cross-sectional shapes are possible, such as, but not limited to, elliptical, circular, semi-circular, rectangular, square, flat, or star-shaped. The filament (415) may, for example, be formed of a tube having at least a partially hollow structure having an inner cavity (601), such as... Figure 6B As shown. Some or all of the filaments (415) may be hollow along their entire length, or, for example, a cavity (601) may exist only in a portion of the length of one or more filaments (415). Alternatively, a woven web (413) may be included, comprising a first subset of filaments (415) having a cavity (601) and another subset of filaments (415) without a cavity, or all filaments without a cavity.

[0127] In another example, the filament can be made by a molding process, such as injection molding. The electrode (109), for example, the wire (417) connected to the electrode (109), and / or other components (e.g., tubes for forming the cavity, reinforcing struts (2702), other wires, etc.) can be placed in the mold (2701) before molding and can be molded as follows: Figure 27The filament shown is overmolded during molding. Components can be completely overmolded, meaning they will be entirely within the molded filament, not reaching the surface of the filament (not exposed on the surface of the filament), and / or partially, for example, when at least a portion of the surface of these components is exposed on the surface of the filament. For example, an electrode can be partially overmolded when at least a portion of its surface is exposed on the surface of the molded filament. However, these structures do not necessarily need to be overmolded, and at least a portion of these structures can be added to the filament after the molding process, and thus added to a subsequent braided web.

[0128] A filament made of an electrically insulating tube with a hollow structure (cavity) can have disadvantages, for example, when an electrode (e.g., in the form of a tube) is placed on the filament and a wire coupled to the electrode is guided inside the cavity of the filament. A small opening in the filament wall is typically used for the transition of the wire through the filament wall. This small opening needs to be sealed to prevent, for example, blood or other liquids from reaching the interior of the filament. In the case where the electrode is a ring electrode placed around the filament, a seal can be made between the filament and the electrode. Typically, this seal is achieved by applying adhesive to the area between the electrode edge and the filament on which the electrode is placed. The adhesive ensures a seal between the electrode and the filament. Another advantage of this solution is that the adhesive on the electrode edge increases the stiffness of the filament immediately adjacent to the electrode, which ensures that if the filament needs to bend in the area where the electrode is placed, the bending of the filament occurs away from the electrode edge, preventing the electrode edge from being exposed. Electrodes may have sharp edges, and exposing such sharp edges can, for example, cause injury to the patient. The drawback of placing a ring electrode on a tubular filament and sealing it with glue is that the seal adds extra material, meaning the diameter of the filament increases where glue is applied, which is problematic for catheters with numerous filaments. Another issue with sealing the electrode to the filament with glue is that the glue may peel off, potentially causing some of the glue to loosen and injure the patient. These problems can be addressed, for example, by using filaments manufactured using a molding process or, for example, by using filaments as described in another example.

[0129] In another example, the filament (415) may take the form of at least a partially hollow structure, for example, comprising a tube made of a non-conductive material (e.g., thermoplastic). An exemplary cross-section of such a filament (415) can be... Figure 31a to Figure 31cThe filament (415) comprising the electrode (109) (e.g. a ring electrode) can comprise at least two tubes (3100) which can be coupled to each other at the location where the electrode (109) is placed on the filament (415). The tubes (3100) can be made of a material having a melting point, for example a material having a melting point lower than the melting point of other structures in the filament, for example a thermoplastic. The coupling of the tubes can comprise a melted material (3101) which can be from, for example, at least one of the tubes (3100). The melted material (3101) can fill the inner cavity of the electrode (109) and seal the electrode and / or a wire (417) coupled to the electrode, or another structure leading from the filament inner cavity to the electrode (109), or any other structure leading to the filament inner cavity, and can ensure that the tubes are connected to each other. The filament can comprise a wire (3102) which can be placed inside the inner cavity of the filament longitudinally and can be led uninterruptedly at least in the area where the electrode (109) is placed on the filament (415), thus, in this area, the tubes (3100) are coupled to each other. The wire (3102) can serve as a reinforcement of the filament.

[0130] The manufacturing process of the filament comprising at least two tubes described in the preceding paragraph can comprise Figure 31a to Figure 31c the steps shown. In the first step, as Figure 31a shown, the tubes (3100) and the electrode (109) are placed on the wire (3102) so that the electrode (109) is placed between the tubes, thus forming an assembly. The wire (417) coupled to the electrode (109) leads into the inner cavity of one of the tubes (3100). In the next step, the whole assembly is heated at least to the melting temperature of the material from which the tubes (3100) are made. The tubes (3100) melt and the melted material from the tube ends adjacent to the electrode flows into the inner cavity of the electrode and fills it up. In the next step, the assembly is cooled down to a temperature which is at least lower than the melting temperature of the material from which the tubes (3100) are made. The result of this step can be seen in Figure 31b and / or Figure 31c .

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

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

[0133] Due to the shrinkage of the melted material of the tube (3100) and due to some material of the tube filling the inner cavity of the electrode during the manufacturing process, the outer diameter of the tube (3100) can be higher than the outer diameter of the electrode prior to the manufacturing process. The outer diameter can be, for example, 1% to 60%, or 3% to 50%, or 5% to 40%, or 10% to 35% higher. The material of the tube (3100) and the ring (3103) can be, for example, thermoplastic, such as nylon, having two different melting temperatures. The materials can be chosen such that the melting point of the material of the ring (3103) can be higher than the melting point of the material of the tube (3100), and the flex point of the material of the ring (3103) can be about the same as the melting point of the material of the tube (3100).

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

[0135] Reducing the filaments at and / or near the intersection region can help to stabilize the woven mesh mechanically by providing more stable intersections, thus stabilizing the expandable basket mechanically, and / or can help to reduce the maximum diameter of the collapsed expandable basket. Having filaments with a reduced diameter at and / or near the intersection region can ensure that the intersection of the filaments remains relatively stable in terms of filament length during expansion and collapse of the basket assembly (expandable basket). This means that the intersection of the filaments remains at a relatively same filament length distance in the collapsed state of the basket assembly (expandable basket) as well as in all expanded states. The mutual angle of the specific filaments that create the intersection changes (e.g. from approximately 2 degrees to 178 degrees and vice versa). Some minor longitudinal movement of the intersection can not be completely avoidable, but is kept within limits that do not harm the dimensions and / or mechanical stability of the woven mesh. This feature can then for example allow to place electrodes at the intersection of the filaments and / or to ensure a stable, predictable desired mutual position of the electrodes and / or their mutual distance.

[0136] On the other hand, the filaments made by the molding process can have a variable cross-sectional shape. This can for example be advantageous in the intersection of the filaments, wherein a different cross-sectional shape of at least one of the filaments included in the intersection can help to stabilize the intersection and / or can help to reduce the maximum diameter of the expandable basket in its collapsed configuration. The cross-sectional shape used at and / or near the intersection region of the intersection of the filaments included in the intersection can for example be semi-circular, rectangular, flat, oval or for example ovoid, while the cross-section of the rest of the filament can be different, for example circular. In case the cross-section of the filament at and / or near the intersection region includes a flat or flat side, this flat or flat side can be the side that is in contact with the other filament that forms the intersection.

[0137] A combination of variable cross-section and variable diameter of the filaments is also possible. For example, the filaments can have a different cross-section and a different (e.g. reduced) diameter at and / or near the intersection region, which can again help to stabilize the woven mesh and thus the expandable basket and reduce the maximum diameter of the expandable basket in the collapsed configuration. The maximum diameter of the expandable basket in the collapsed configuration can for example be reduced by 0.01% to 50%, or by 0.05% to 30%, or by 0.1% to 15%.

[0138] Variable diameter and / or variable cross-section can not only be used at and / or near the intersection region of the filaments, but also at different regions of the filaments. For example, a reduction of the diameter and / or a change of the cross-section can allow to form weaker and / or stiffer regions on the filament, for example to form living hinges during the molding process of the filament.

[0139] In another example, the molded filaments need not be molded straight, but can have been made with at least one bend or curvature (2601). The bend and / or curvature (2601) can for example be located and / or adjacent at least one intersection region of the filaments, or for example adjacent the proximal or distal end of the filaments. One example of such a solution can be seen in Figure 26 . The preformed curvature (2601) can be used for example for further stabilization of the woven mesh, and thus, for further stabilization of the expandable basket. The filaments can be preformed in such a way that heat stabilization of the woven mesh after weaving can not be necessary.

[0140] In another aspect, the filaments can be molded including at least one region of the filaments being split during the molding process and / or at least one region of additional loops (2201) being formed on the filaments (415). Such at least one split region and / or additional loops (2201) can for example be formed at and / or adjacent at least one intersection region (2202) of the filaments, and can for example be used as a support (fixation) at at least one intersection of two filaments (415) after the filaments (415) have been woven into a woven mesh. In another example, the filaments can include electrodes within the split (for example within a region bounded by the beginning and end of the split of the filament) and / or within a loop region (2203) of the filament bounded by a first connection point (2204) of the loop (2201) to the filament (415) and a second connection point (2204) of the loop (2201) to the filament (415), which can be seen in Figure 22 .

[0141] An intersection region of a filament is a region on the filament that participates in an intersection in the woven mesh structure. In some cases, at least one electrode can be placed at and / or adjacent an intersection region on a filament. In case the electrode is located at and / or adjacent an intersection region of a first filament included in a particular intersection, a second filament included in that intersection can not include an electrode located at and / or adjacent the intersection region of that particular intersection. This means that there can be at most one electrode on any intersection of the woven mesh and the expandable basket. In another aspect, in case an electrode is included in an intersection, it can be included at and / or adjacent a region of the filament that is further laterally distanced from the longitudinal axis in that particular intersection, which means that the electrode is placed on the outer circumference of the expandable basket.

[0142] In examples with molded filaments, as mentioned above, such molded filaments can have a different diameter and / or cross-section in at least one intersection area than the rest of the filament. In one particular example, where the electrode is included in the intersection, the first filament including the electrode can have a cross-section corresponding to the cross-section of the electrode in the intersection area (e.g. a circular cross-section), and can include a loop at or near the intersection area, the second filament in the intersection can have e.g. a smaller diameter and / or a different cross-section than the rest of the filament (e.g. can have a flattened, rectangular, elliptical or semi-circular cross-section in the intersection area, while having a circular cross-section in other areas).

[0143] However, this does not mean that a filament including an electrode at or near an intersection area cannot have a different diameter or a different cross-section in the intersection area than the rest of the filament. For example, an electrode included on a filament can have a different diameter or a different cross-section than the rest of the filament.

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

[0145] In another aspect, the filament can be further mechanically reinforced, for example, by inserting a mechanical support into the inner lumen of the filament. Such a mechanical support can, for example, be in the form of a strut placed in the inner lumen of the filament. The strut can be placed over the entire length of the filament, or, in the case of a filament that does not have an inner lumen over its entire length, over the entire length of the inner lumen of the filament. Another possible option is to place the strut only in a part of the length of the inner lumen, thereby leaving a part of the filament reinforced with the strut and another part not reinforced with the strut. The strut can, for example, be made of Nitinol, for example, with an electrically insulating layer, for example, made of polyamide (PA), polyimide (PI) or PTFE. Other possible materials suitable for the strut can be polymers or thermoplastics, for example, nylon, fluorinated ethylene propylene (FEP), polyethylene (PE), PEBA, PEEK, polyimide (PI), polypropylene (PP), PTFE, polyurethane (PU), polyethylene terephthalate (PET) or, for example, silicon.

[0146] In an example with a molded filament, at least one reinforcing strut (2702) can be placed in the mold (2701) and can be overmolded. In this example, the strut (2702) has to be made of a material with a higher melting point than the filament. The at least one strut (2702) can again be placed in the entire length of the filament or only in a part of the length of the filament, thereby leaving a part of the filament reinforced with the strut and another part not reinforced with the strut. An example of a strut that has been placed in a mold can be seen in Figure 27 .

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

[0148] The braided mesh can be constructed in such a way that all filaments contained within the braided mesh can be reinforced, or only a part of the filaments contained within the braided mesh can contain a reinforcing material, while another part of the filaments can not contain a reinforcing material.

[0149] At least one filament forming the braided mesh can include at least one location in which the local mechanical strength of the filament structure is weaker than that of the rest of the filament. Such a location can form a so-called living hinge (2103), as Figure 21The living hinges can be used to define more or less precise positions at which the filaments included in the woven mesh are more easily bent, and thus the filaments within the expandable basket are more easily bent, and the bends on the filaments form smaller radii (or direct kinks) compared to filaments without such living hinges. This can further help to define a more predictable shape of the expanded expandable basket in at least one expanded position. Establishing such living hinges on the filaments can include thinning or cutting a portion of the filaments. Thinning can be done, for example, by pressing or heat forming a specific location of the filaments. Thinning can be done around the entire circumference of the filaments, or only partially. Partially asymmetric thinning can be advantageous, as the hinge thus formed can define a specific direction in which the filaments are more easily bent than in other directions. In one example of an expandable basket, the living hinges formed on the filaments can allow the filaments to be more easily bent, and thus the woven mesh to be more easily bent, for example, in a radial direction from the longitudinal central axis of the catheter. For example, living hinges forming smaller radii or kinks on the filaments in the distal body portion (421) of the basket assembly body, or in the terminal assembly region, can help the expandable basket (basket assembly body) to shape (in one of its expanded configurations) in a region located distally of a plane intersecting the basket assembly in the portion having the highest diameter, such that at least some distal portion of the expandable basket (in the region of the distal body portion) can form a larger angle (radially from the elongated axis) compared to the proximal portion of the basket (in the region of the proximal body portion). In an extreme case, the distal portion of the expandable basket (in the region of the distal body portion) can form an angle of 90° or more (radially from the elongated axis) to achieve an expanded state in which at least a portion of the expandable basket including the electrodes becomes the longitudinally most distal portion of the catheter, without any other portion protruding more distally (e.g., the terminal assembly). Such a configuration can be advantageous, for example, in ablation of a relatively flat treatment site.

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

[0151] At least one of the active hinges described in the preceding section can be included on at least a portion of the woven mesh, wherein the filaments are merged together (on a merged structure). In this case, the active hinge is a location on the merged structure that is locally mechanically weaker than the rest of the merged structure, and can be formed by, for example, thinning or cutting the merged structure after merging. Another option for creating an active hinge on a merged structure is to pre-thin or pre-cut the polymer tube prior to inserting the filaments, particularly in cases where the merged structure comprises a polymer tube and the filaments are merged in the inner lumen of the tube or in multiple inner lumens of a multi-lumen tube. Such pre-thinning of the tube can be accomplished, for example, by extrusion, thermoforming, or by molding (e.g., injection molding).

[0152] The active hinge can be formed within a region of the distal body portion, the central body portion, and / or the proximal body portion of the basket assembly body. In cases where the active hinge is located in a region of the proximal body portion, the active hinge can be placed in a proximal region of, for example, 0% to 20% or 0% to 15% or 0% to 10% of the collapsed basket length. In cases where the active hinge is located in a region of the distal body portion, the active hinge can be placed in a distal region of 0% to 20% or 0% to 15% or 0% to 10% of the collapsed basket length. The active hinge can also be part of the end fitting assembly. In cases where the active hinge is placed in the central body portion, the hinge can be placed on a plane that intersects the basket assembly at a portion having the highest diameter, or from -20% to +20% or from -10% to +10% or from -5% to +5% away from this plane or the center of the collapsed basket.

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

[0154] The electrodes can be operated individually or in pairs or groups, or a portion of the electrodes can be operated individually and a portion of the electrodes can be operated in pairs or groups.

[0155] In one example, electrodes can be placed at areas where filaments cross each other (filament crossing points). Such locations can be advantageous because a more stable distance between electrodes can be maintained during different configurations of the expandable basket, and such configurations can also advantageously prevent unwanted contact between electrodes, especially when the expandable basket is not in a fully expanded configuration.

[0156] All electrodes included in the expandable basket can be located at filament crossing points, or only some electrodes can be located at filament crossing points, and some electrodes can be located elsewhere.

[0157] Each filament can also include one type or different types of electrodes, or different filaments can accommodate different types of electrodes. Different types of electrodes can be understood as electrodes having different functions, e.g., ablation electrodes, measurement electrodes, etc., or physically different electrodes having, e.g., different shapes, sizes, designs, materials, etc., or a combination of electrode types having different functions and physical properties. For example, in a configuration where ring-shaped electrodes are placed on the filaments, all electrodes can have the same diameter and can have different lengths, so there can be, e.g., two or more groups of such electrodes, each group having a different length. The number of electrodes in each group can be the same or different. In an extreme example, each electrode on the expandable basket can have a different length. In a configuration with ring-shaped electrodes, such electrodes can 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 can have a length of 0.1 mm to 10 mm, or 0.2 mm to 8 mm, or 0.3 mm to 6 mm, or 0.4 mm to 4 mm.

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

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

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

[0161] For example, the electrode layout on the expandable basket can ensure a continuous circular ablation zone and can form a pattern even if the expandable basket is held in various expansion positions between the fully collapsed and the fully expanded position.

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

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

[0164] The pattern formed by the electrodes can be located on the main body of the basket assembly, in particular on the distal main body portion, the central main body portion or the proximal main body portion, as shown in Figure 7BThe pattern can even extend into more than one of these sections. For example, for treatment of a flat treatment site located distally from the basket assembly, the electrode pattern can advantageously be located on the distal portion of the basket assembly. In particular, the pattern can be located in a cross-section of the basket assembly that is bounded by an area that is at an angle (703) of 0 to 90° of the central axis (203) from the center of the plane (425) that intersects the basket assembly in the section with the highest diameter (in one of its expanded configurations). In some configurations, the pattern can be located partially on the distal portion of the basket assembly body, partially on the central portion of the basket assembly body. In some configurations, the pattern can be located in a cross-section of the basket assembly that is bounded by an area that is at an angle (705) of 0 to 120° of the central axis (203) from the center of the plane (425). This placement of the pattern can be particularly advantageous for treatment of ostia of vessels, for example, ostia of pulmonary veins. In case the treatment site has a tubular shape, the pattern can be placed on the middle portion of the basket assembly, in particular in a cross-section of the basket assembly that is bounded by an area that is at an angle (707) of 45° to 135° of the central axis (203) from the center of the plane (425). If the flat treatment site is located proximally from the basket assembly, for example, a septum, the electrode pattern can be located on the proximal body portion of the basket assembly, or partially on the proximal body portion and partially on the central body portion, in particular in a cross-section of the basket assembly that is bounded by an area that is at an angle (709) of 90° to 180° of the central axis (203) from the center of the plane (425). Alternatively, the electrodes can be placed in all portions of the expandable basket, forming a pattern in all portions, and only the pattern that is necessary or optimal for performing a particular treatment can be selected to perform the treatment.

[0165] The particular pattern can be formed by all electrodes or only some electrodes placed on the expandable basket. The pattern can have a different number of electrodes in various expanded positions between the fully collapsed and fully expanded positions of the expandable basket. The distance between adjacent electrodes in the pattern can be, 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 wires. The electrodes can be electrically or communicatively connected to other units or components of the pulse electric field ablation device, and for example, to a mapping device, an EP display device, a pacing device, an ECG recording device, a catheter signal interconnection circuit, an ECG triggering circuit, an electrical control circuit, a GUI unit, or a remote control unit. In addition to the previously mentioned ring electrodes, the electrodes can have any of a number of different shapes, for example, a tube wrapped around a filament, a coiled metal sheet, a square and / or rectangular or other shaped electrically conductive material attached to a filament. Other possible forms of electrodes (109) can be an elongated continuous electrode stretched along the surface of a portion of the filaments (415) such that the electrode does not contact the intersection points of the filaments (415) in the woven mesh (413), as shown in Figure 8 The electrodes (109) can be attached to the specific filaments (415) of the expandable basket by any means, for example, by mechanical attachment, swaging, crimping, gluing, lamination, deposition, and / or welding. The electrodes can be made of any electrically conductive material, for example, copper, gold, steel, titanium, platinum, platinum iridium, and the like. In cases where at least one of the filaments is made of an electrically conductive material, the filament can also serve as an electrode. In cases where the entire electrically conductive filament is not insulated, the entire filament can serve as an electrode, and in cases where the filament is electrically insulated, for example, partially, the exposed uninsulated portion can serve as an electrode.

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

[0168] The design of the expandable basket is particularly advantageous in cases where the wire is positioned along the entire length of the filament, wherein the filament is bent and returned to the expandable basket, rather than being cut at the distal end of the expandable basket. Because the specific wire is configured to carry electrical pulses between the electrode and the pulse generator, the insulation of the cut filament with the wire inside would be very challenging in the terminal assembly. On the other hand, in examples comprising a bent filament with the wire inside, the insulation of the terminal assembly can be easily ensured.

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

[0170] The construction of the braided mesh made of electrically insulating material (with one or more wires inside the hollow filament, as described above) can be particularly advantageous for ablation systems based on the principle of pulsed electric field ablation, based on pulsed electric fields. The further described method of pulsed electric field ablation requires the generation of an electric field around the electrode. In order to generate the electric field, the electrical pulses must be carried by the specific wire between the electrode and the pulse generator. When the filament is not electrically conductive and the wire is kept inside the filament as described herein, the electrical insulation of the specific wire can be ensured even at voltage levels of several thousand volts (e.g., from 1 kv to 10 kv) carried by the wire. However, it is also possible to select a braided mesh with at least one or more filaments made of an electrically conductive material (e.g., nitinol, copper, stainless steel, steel, aluminum, gold, platinum, or silver). Such electrically conductive filaments can be insulated or uninsulated, or just partially insulated. The filaments can not only guide the electric current, but also act as electrodes (when uninsulated or only partially insulated) and / or as a further mechanical support of the braided mesh, thus as an expandable basket.

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

[0172] The woven mesh into which the conductive wires are inserted can be connected to the outer elongated shaft and the inner elongated shaft, forming part of the expandable basket and basket assembly. Before or after connecting the woven mesh to the elongated shafts, electrodes can be connected to specific filaments of the woven mesh. The pulse generator is a component that generates electrical signals for the catheter electrodes. The pulse generator can allow setting, for example, the amplitude, shape and / or number of pulses during activation of the electrical pulses. The pulse generator can also diagnose the electrical waveform to measure the power. The pulse generator can operate in synchronization with an ECG device or another part of the ablation system or device.

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

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

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

[0176] The treatment site can be located in the body, for example, in or on the heart, for example, in a heart chamber, in particular, for example, in the left atrium of the heart. The treatment site can comprise, for example, a pulmonary vein ostium. Other locations of the treatment site can be, for example, all tubular tissues, organs or blood vessels in the body, or, for example, a tumor site.

[0177] As the distal end of the catheter is delivered to the treatment site, the basket assembly of the catheter unfolds from a constricted or semi-constricted configuration to an expanded configuration. This unfolding can be caused by the pre-stretched shape of the braided mesh or its filaments, or by the linear displacement of the inner elongated axis against the outer elongated axis along the longitudinal central axis of the catheter, by the tension of additional support structures (e.g., internal coils or balloons (not shown)), or by a combination thereof.

[0178] The distal tip (107) of the catheter can then be positioned near the target tissue at the treatment site (1001), for example, 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 a set of electrodes (109) placed on the basket assembly (401) may be in contact with the tissue at the treatment site (1001). Figure 10 A schematic diagram of the example location can be seen in the diagram. The terminal assembly (411) can improve the contact between the electrode and the treatment site through its flat design without distal protrusions. When there are no distal protrusions on the basket assembly (401), especially on the distal portion (405) of the basket assembly, it is easier to make contact between the electrode and the treatment site, even when the treatment site is relatively flat.

[0179] After positioning the distal catheter near the treatment site, optional measurement steps can be performed with or without the catheter. Different types of measurements can be performed for purposes such as diagnosing the type or quality of tissue at or around the treatment site, the spatial position of the distal catheter tip, particularly the spatial position of the distal catheter tip against the treatment site, contact between the distal catheter tip and / or a specific electrode and the target tissue at the treatment site, or to understand 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 on an expandable basket, for example, on filaments of a braided mesh. The measuring electrode can be a different electrode from the ablation electrode, or the ablation electrode can be used for measurement. A separate measuring electrode can also be combined with an ablation electrode that has a measuring function on a single distal catheter tip. Measurement steps can be performed using separate measuring devices, 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 echo device, an esophageal temperature measurement device, a fluoroscopy device, an RTG device, an MR device, etc. During the ablation process, the measurement steps can be performed once or repeated several times.

[0180] The ablation of the target tissue at the treatment site (1001) is performed, for example, using the principle of pulsed electric field ablation induced by a pulsed electric field with appropriate parameters. Although the terms "electric field" or "pulsed electric field" are used herein, the electric field considered herein may also include magnetic components.

[0181] The process of basket assembly deployment, measurement and ablation can be performed in several stages. For example, the expandable basket can be delivered to the vicinity of the treatment site in a fully collapsed configuration. After delivery, it can be expanded to its first expanded configuration. For example, the pre-stretched shape of the braided mesh and / or filaments can cause this first transition. 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 this location in any order.

[0182] The basket assembly can then be expanded to a second expanded configuration. The second expanded configuration can be achieved, for example, by a linear displacement of the inner elongated shaft along the longitudinal center axis of the catheter against the outer elongated shaft. In this configuration, for example, further manipulation of the basket assembly as well as measurement and / or ablation can be performed. Further repositioning, measurement and / or ablation can also be performed in this location in any order.

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

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

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

[0186] The pulses can be monophasic or biphasic. Biphasic pulses can be symmetric or asymmetric. The pulses can be repeated from 1x to 100000x. The frequency of the high frequency pulses can vary from 0.1 Hz to 10 Hz. The amplitude of the monophasic pulses (Um) can vary from 100 V to 10 kv, while the peak-to-peak amplitude of the biphasic pulses can vary from 200 V to 20 kV.

[0187] Figure 16 Examples of what can be part of a protocol of pulsed electric field ablation (PFA) and as an illustration of terms and expressions in relation to PFA protocols. A PFA protocol comprises a series of electric pulses (1601) and pauses (1603, 1607, 1615). The electric pulses (1601) can further be organized into units with some hierarchy, e.g. trains (TR) and bursts (B).

[0188] The electric pulses (1601) can be defined by e.g. a shape with a certain voltage, an amplitude (Um) and a pulse length with a duration (tl). In the case of monophasic pulses, the pulse amplitude (Um) can be negative or positive (the pulse can have a negative or positive voltage). The electric pulses (1601) can be separated from each other by an inter-pulse pause (1603) defined by a duration (t2) and a voltage (Up). The voltage during the inter-pulse pause (1603) can drop to 0 V, or can have a positive or negative voltage value (Up). The absolute voltage value (Up) of the inter-pulse pause is less than the absolute voltage (amplitude (Um)) of the adjacent electric pulse (1601), in particular up to 50% of the adjacent electric pulse amplitude (Um). In the case of electric pulses with a positive amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) will remain positive between 0 V and the electric pulse (1601) amplitude (Um), and in the case of electric pulses (1601) with a negative amplitude (Um), the voltage value (Up) of the inter-pulse pause (1603) will remain negative between 0 V and the electric pulse amplitude (Um). Figure 17a Examples of inter-pulse pauses (1603) with a voltage different from 0 V are shown in the middle. Biphasic pulses can be symmetric or asymmetric in at least one of time, amplitude or energy.

[0189] Figure 17bExamples of biphasic electrical pulses are shown. Biphasic pulses can have a positive phase (1701) with the same amplitude (voltage) and a negative phase (1703) with the same duration (tlO, tl2) (exemplary pulses A, D), or the amplitude and / or duration (tlO) of the positive phase and the amplitude and / or duration (tl2) of the negative phase can be different (exemplary pulses B, C). The resulting pulse can then have the same energy in the positive and negative phases of the pulse, or the energy in the positive and negative phases of the pulse can be different. Biphasic pulses with the same energy in both phases can be referred to as symmetric biphasic pulses. Symmetric biphasic pulses can be balanced (in the case of the same duration and amplitude of the two phases of the pulse), or unbalanced (in the case of different amplitude and / or duration of each phase). Unbalanced biphasic pulses have phases with different energies. Exemplary biphasic pulses A, B, C have no pause between the specific phases of the pulse (inter-phase pause), exemplary pulse D is a biphasic pulse with an inter-phase pause (1705). The duration of the inter-phase pause of the pulse can be from 0 to 50 ps or from 0 to 10 ps or from 0 to 5 ps.

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

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

[0192] When pulses of amplitudes (Um) in the range of hundreds to thousands of volts are applied, there is a certain risk of causing depolarization of the ventricular muscle and unwanted ventricular rhythms in the heart, even when applied in the atrium. The depolarization can be caused directly by the electric field or by a secondary energy induction in another device, e.g. a catheter placed in or near the atrium or ventricle or both. The time in which the active sequence (individual pulses, trains and / or bursts) is suspended with the following described can create an effect called overdrive. The overdrive effect is commonly used in ablation catheterization procedures to suppress the risk of adverse heart rhythms by using an external pacemaker. The proposed PFA protocol has the advantage that, in case the treatment (ablation) electric pulses cause depolarization of the heart muscle, it can also act as a pacing stimulation pulse for the heart, so that no additional pacing device (e.g. an external pacemaker) is needed to synchronize the pacing device’s pulses with the treatment pulses of the PFA protocol. This in turn means that, in this case, no pacing device is needed to control the number of ventricular contractions per minute, to detect each ventricular contraction from the surface ECG and then to trigger the ablation pulses accordingly.

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

[0194] The PFA protocol can have other positive effects on the ablation outcome, e.g. reducing the risk of causing adverse ventricular rhythms and / or maximizing the PEF application efficiency.

[0195] However, while electroporation is described as a major trigger for cardiomyocyte death following PEF application, actual cell death can also be caused by, for example, electrical breakdown of the cardiomyocyte membrane, mitochondria, or nucleus; by tearing individual / groups of cardiomyocytes (or cell populations) (e.g., by disrupting intercalated discs, directly through an electric field or by mechanical damage through hypercontraction); by damaging the myofibrils or myofibrils; by excessive contraction leading to insufficient ATP consumption and production in cardiomyocytes; by relaxing intercellular junctions in cardiomyocytes; by myolysis of muscle cells; by wrinkling of cardiomyocytes directly under the influence of an electric field or by mechanical damage through hypercontraction; by irreversible damage to the calcium cycle (whether it be the sarcoplasmic reticulum, ion pumps, calcium channels, or non-physiological function of calcium-binding proteins); by myocardial calcium overload-mitochondrial swelling (due to excessive contraction or damage to the cardiomyocyte membrane or non-physiological function of calcium channels); or by the formation of reactive oxygen species (ROS) and subsequent oxidation of membrane phospholipids by PEF.

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

[0197] In some respects, the electrode (109) placed on the distal component can operate in a hybrid mode of the previous two types. An example of this mode is... Figure 11 As shown. In this mode, only the electrode 109 placed on the distal tip 107 is used for ablation. There is a first single electrode or group of electrodes operating in a mode having a first polarity (P1) and a second single electrode or group of electrodes operating in a polarity (P2) different from the operating mode of the first electrode or group of electrodes (which may be opposite polarities). The surface area or the sum of the surface areas of the first electrode or the first group of electrodes is significantly smaller than the surface area or the sum of the surface areas of the second electrode or the first group of electrodes. For example, a third group of electrodes may be present, operating in a third mode under high impedance (HI) conditions, wherein 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 the electrode operation in this hybrid mode is that the generated electric field can have a more uniform current density compared to the bipolar mode. Another advantage of the hybrid mode of operation is that the electric field formed in this mode can reach deeper into the target tissue in some aspects compared to the bipolar mode. In the case of ablation of a heart chamber, the depth of the ablation of the target tissue (which in one example can include cardiac muscle tissue) can reach 5 mm.

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

[0200] For example, in cases where it is advantageous to reduce the size of the electrodes, the example of a group of electrodes (more than one electrode) operated in a mode with a first polarity (P1) is more advantageous than the example of a single electrode operated in a mode with a first polarity (P1). In cases where it is necessary or desirable to increase the number of electrodes, it can be advantageous or necessary to reduce the size of the electrodes. For example, in cases where it is necessary to perform a more precise mapping of the treatment site or a more precise and / or uniform ablation of the target tissue of the treatment site, a greater number of electrodes is required. Since the treatment site can be part of the human anatomy, the overall size of the pulsed electric field ablation device (especially a catheter with a distal tip of the catheter) must be limited according to the human anatomy. It follows from this that if the ablation device requires more electrodes, the size of the electrodes must be limited to a size that can fit into the limited size of the key components of the pulsed electric field ablation device, for example, the catheter and / or its distal tip, and / or its basket assembly, for a certain number of electrodes. Another advantage of smaller sized electrodes is that such an arrangement contributes to an increase in the depth of ablation.

[0201] Smaller sized electrodes can have other advantages, for example, in examples in which the same electrode is used for ablation and measurement, which means that the same electrode must be configured to deliver high voltage pulses and record measurements. For example, in the measurement of ECG signals, smaller electrodes can be advantageous.

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

[0203] The enlargement of the electrode surface area in the first set and the resulting formation of virtual electrodes can result in a reduced voltage that needs to be induced in the electrodes and / or the elimination of sparking, mainly at the edges of the electrodes. However, the concept of a disproportionate surface area of the electrodes in the first and second set can be preserved, which means that the surface area or the sum of the surface areas of the first electrode or the first set of electrodes is significantly smaller than the surface area or the sum of the surface areas of the second electrode or the second set of electrodes. The ratio of the surface area of the electrodes or the sum of the surface areas of the first set of electrodes to the sum of the surface areas of the second set of electrodes can be between 2:3 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 the first set of electrodes operating in the mode with the first polarity can significantly reduce the electric field strength in the vicinity of the electrodes. For example, using four electrodes instead of one in the first set of electrodes operating in the mode with the first polarity reduces the electric field strength at the surface of the electrodes by a factor of four, while in the example using three electrodes the electric field strength is reduced by a factor of two. This reduction in strength can allow for using lower voltages on the electrodes compared to a solution where only one electrode is operated in the mode with the first polarity. This reduction can additionally or alternatively increase the depth of the ablation of the target tissue by increasing the area of the electric field per centimeter at a certain voltage. The value of the voltage per centimeter in the electric field region can be, for example, from 50 V / cm to 3000 V / cm, or from 100 V / cm to 1500 V / cm, or from 250 V / cm to 1000 V / cm.

[0205] A particular electrode on the distal tip of the catheter can be switched to one or more modes during ablation. The particular electrode can be switched during one ablation cycle or several ablation cycles. The electrode can be switched to one or more modes several times during one ablation cycle or several ablation cycles. In certain aspects, it is even possible to have two or more sets of electrodes operating in the mode with the first polarity at the same time while one set of electrodes is operated with a different polarity, with or without electrodes operated in the high impedance state.

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

[0207] Considering the mixed mode of operation of the electrodes and / or the target to form a virtual electrode, an electrode layout or spatial pattern on the distal tip can be formed. Because the electrodes can be switched to one or more modes during ablation, it is possible that the resulting virtual electrode can have different spatial shapes, which means that the electric field formed around and between the virtual electrodes can have different shapes, have different magnetic field structures and / or different electric field density and strength. In Figure 13A and Figure 13B Examples of spatial patterns of electrodes on the distal tip, in particular on the expandable basket, can be seen in Figure 13A A front view of a basket assembly (401) with a spatial pattern of electrodes (109) adapted to form a virtual electrode by switching the electrodes (109) to different modes of operation with a first polarity and with a different polarity and / or with a high impedance state is shown.

[0208] Figure 13BAgain, a front view of the basket assembly (401) is shown, this time with an electrode spatial pattern adapted to form virtual electrodes by switching the electrodes (109) to different modes, however this time, the electrodes are placed in areas where the filaments (415) cross each other (filament crossing points).

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

[0210] Electrodes in a high impedance (higher than 500 Ω) state can help shape the electric field formed between and around the electrodes in the first and second groups and / or between or around the virtual electrodes. In one example, assigning a high impedance state to electrodes that are spatially adjacent to electrodes operated in a mode with a first polarity can have a positive effect on the shape of the electric field compared to the mode of operation of electrodes that are not in a high impedance state, enabling a part of the electric field that can cause ablation to reach deeper into the target tissue at the treatment site. This phenomenon can have a positive effect on the quality and uniformity of the ablation process. Electrodes in a high impedance state can be placed spatially between the first group of electrodes and the second group of electrodes.

[0211] Figure 15A shows an exemplary pattern of the electrode (109) in more detail. The electrode (109) forms a repeating cross, square, or rectangular pattern on the filaments (415) of a braided mesh in one extended configuration of the expandable basket. From this view perpendicular to the cross-section (e.g., contacting the expandable basket at the intersection (1501) of four adjacent electrodes), the pattern appears two-dimensional but is actually three-dimensional because the electrode (109) is attached to, or a portion of, the filaments of the braided mesh, which forms the expandable basket, and thus the pattern adapts to the curvature of the expandable basket. This pattern of electrodes is advantageous in embodiments using a set of electrodes operating in a mode with a first polarity (P1). In this example, a set of four adjacent electrodes operating in a mode with the first polarity (P1) and thus forming a first dummy electrode (1401) would have a cross shape as shown in Figure 15A, or a square or rectangle as shown in Figure 15B. The advantage is that the two virtual electrodes (1401) formed by the two shapes are combined with the second virtual electrode, and with the help of the electrode in a high impedance state, it is possible to form an electric field with specific quality (shape, amplitude, density, potential gradient) suitable for the ablation of the target tissue.

[0212] Figure 15C shows an example of an electrode pattern in which the electrode (109) is located in the region where the filaments (415) intersect each other (filament intersection). An exemplary set of electrodes operating in a mode having a first polarity (P1) is also shown herein.

[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 set of electrodes forming the virtual electrodes can differ in the contracted configuration and / or different expanded configurations of the expandable basket. For most expanded configurations of the expandable basket, the rectangles and squares formed by the electrodes described above will be angled and will form a shape closer to a rhombus or a long oblique rectangle. The same applies to the angles forming the cross and passing through the two dashed lines of the electrodes; in most expanded configurations, these angles are not right angles.

[0214] Figure 34 An exemplary pattern of electrodes (109) embossed on a flat two-dimensional plane and mounted on an expandable basket is shown. The electrodes are positioned such that, in all expansion configurations of the expandable basket, the distance (3401) between the nearest points of the electrodes (109) longitudinally adjacent to each other in a direction perpendicular to the central axis (203) ±45° is less than 2 mm. Figure 34 An example of such a pair of electrodes (109) can be seen in the direction of the central axis (203) ±45°, which are longitudinally adjacent to each other.

[0215] When high-voltage pulses are used in the human body, for safety reasons it can be desirable to synchronize the delivery of the pulses with the cardiac cycle, for example, in order to avoid ventricular rhythm. The pulsed electric field ablation device can include or use a device for such synchronization, including triggering the pulse delivery by such a synchronization device. The synchronization device can be, for example, an ECG device.

Claims

1. An ablation device comprising a generator configured to generate electrical pulses having an amplitude of 100 V to 5000 V and coupled to at least one electrode, the generator comprising: a power supply unit; a capacitor unit; and a DC / DC converter unit coupled between the capacitor unit and the electrodes; and wherein the DC / DC converter unit is configured to electrically disconnect the generator from the electrodes in less than 50 ms.

2. The ablation device of claim 1, wherein, The DC / DC converter unit comprises an output capacitor and a safety discharge resistor configured to discharge the output capacitor in less than 50 ms.

3. The ablation device of claim 2, wherein, The DC / DC converter unit comprises one of a thyristor or a contactor, wherein the thyristor or the contactor is configured to short-circuit the output capacitor.

4. The ablation device of claim 1, further comprising an electrical control circuit configured to receive and evaluate data comprising at least one measured parameter from the ablation device, and further configured to activate the DC / DC converter unit to electrically disconnect the generator from the electrodes when at least one of the measured parameters exceeds a predetermined boundary.

5. The ablation device of claim 4, wherein, The measured parameter is one of temperature, impedance, current or voltage.

6. An ablation device for pulsed electric field ablation, the ablation device comprising a generator configured to generate electrical pulses and coupled to at least one electrode, the generator comprising: a power supply unit; a capacitor unit; and a DC / DC converter unit coupled between the capacitor unit and the electrodes; and an output capacitor emergency system; wherein the output capacitor emergency system, when activated, is configured to discharge the output capacitor and to electrically disconnect the generator from the electrodes.

7. The ablation device of claim 6, wherein, The output capacitor emergency system comprises a safety discharge resistor configured to discharge the output capacitor.

8. The ablation device of claim 6, wherein, The output capacitor emergency system comprises one of a thyristor or a contactor, wherein the thyristor or the contactor is configured to short-circuit the output capacitor.

9. The ablation device of claim 6, wherein, The output capacitor emergency system is configured to discharge the output capacitor and to electrically disconnect the generator from the electrodes in less than 50 ms.

10. The ablation device of claim 6, further comprising a switch unit, wherein, The DC / DC converter unit is coupled between the capacitor unit and the switch unit.

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

12. A generator for an ablation device, the generator configured to generate electrical pulses and coupled to at least one electrode, the generator comprising: a power supply unit; a capacitor unit; and a DC / DC converter unit comprising an output capacitor; and wherein the DC / DC converter unit is configured to discharge the output capacitor and to electrically disconnect the generator from the electrodes.

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

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

15. The generator of claim 12, wherein, The DC / DC converter unit is configured to discharge the output capacitor and electrically disconnect the generator from the electrode in less than 50 ms.

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

17. The generator of claim 12, wherein, The DC / DC converter unit comprises a DC / DC converter without feedback.

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

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

20. The generator of claim 12, wherein, The DC / DC converter unit comprises a two winding and a series resonant converter.

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

6.

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

23. The generator of claim 12, wherein, The DC / DC converter unit has an input voltage from 100 V to 5000 V.

24. The generator of claim 12, wherein, The DC / DC converter unit has an output voltage from 150 V to 5000 V.

25. A method of controlling an ablation device for pulsed electric field ablation, the method comprising: A generator and at least one electrode coupled to the generator are provided, the generator comprising: a power supply unit; a capacitor unit; and a DC / DC converter unit comprising an output capacitor and an output capacitor emergency system; providing an electrical control circuit coupled to the output capacitor emergency system and at least one other part of the ablation device; receiving data from the electrical control circuit, the data comprising at least one measured parameter from the at least one other part of the ablation device; evaluating the data with the electrical control circuit; activating the output capacitor emergency system; and discharging the output capacitor and electrically disconnecting the generator from the electrode when the measured parameter exceeds a predetermined boundary.

26. The method of claim 25, further comprising the steps of: A safety discharge resistor is provided in the DC / DC converter unit; and discharging the output capacitor to the safety discharge resistor.

27. The method of claim 25, further comprising the steps of: At least one of a thyristor or a contactor is provided in the DC / DC converter unit; and short-circuiting the output capacitor via one of the thyristor or the contactor.

28. The method of claim 25, wherein, The measured parameter is one of a temperature, an impedance, a current or a voltage.

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

30. The method of claim 25, wherein, The measured parameter is a voltage and the method further comprises the steps of: providing a switching unit in the generator, the switching unit comprising at least one switch; and measuring a voltage at an output of at least one of the switching unit or the switch.

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