Short circuit of the electrode

Abstract

To provide a medical system.SOLUTION: In one embodiment, a medical system includes a catheter configured to be inserted into a body part of a living subject, the catheter including: a deflectable element having a distal end; an expandable distal end assembly disposed at the distal end of the deflectable element, comprising a plurality of assembly electrodes, and configured to expand from a collapsed form to an expanded deployed form; a proximal electrode disposed at the distal end of the deflectable element proximally to the expandable distal end assembly, and extending circumferentially around the deflectable element; and at least one electrical connection configured to electrically connect together at least two of the assembly electrodes to act as a combined assembly electrode. The medical system also includes an ablation power generator configured to be connected to the catheter, and apply an electrical signal between the combined assembly electrode and a selected electrode.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to medical devices, and more particularly, but not exclusively, to ablation catheters.

Background Art

[0002] A wide range of medical procedures involve placing a probe, such as a catheter, within a patient's body. To track such a probe, position sensing systems have been developed. Magnetic position sensing is one of the methods known in the art. In magnetic position sensing, a magnetic field generator is typically placed at a known position outside the patient. A magnetic field sensor within the distal end of the probe generates an electrical signal in response to these magnetic fields, and these signals are processed to determine the coordinate position of the distal end of the probe. These methods and systems are described in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, International Publication No. 1996 / 005768, and U.S. Patent Application Publication Nos. 2002 / 0065455, 2003 / 0120150, and 2004 / 0068178. Position may also be tracked using impedance or current-based systems.

[0003] One medical procedure in which these types of probes or catheters have proven to be extremely useful is in the treatment of cardiac arrhythmias. Cardiac arrhythmias, and particularly atrial fibrillation, are prevalent and dangerous medical conditions, especially in the elderly population.

[0004] The diagnosis and treatment of cardiac arrhythmias involve mapping the electrical properties of cardiac tissue, particularly the endocardium, and selectively ablating cardiac tissue by application of energy. Such ablation can stop or modify the propagation of unwanted electrical signals from one part of the heart to another. The ablation process destroys unwanted electrical pathways by forming non-conductive lesions. Various modes of energy delivery have been disclosed heretofore for the purpose of forming lesions, including the use of microwaves, lasers, and more generally radiofrequency energy to create conduction blocks along the walls of cardiac tissue. In a two-step procedure where ablation is performed after mapping, typically a catheter containing one or more electrical sensors is advanced into the interior of the heart, and the electrical activity at each point within the heart is sensed and measured by obtaining data at multiple points. These data are then utilized to select the target region of the endocardium to be ablated.

[0005] Electrode catheters have been commonly used in the medical field for many years. Electrode catheters are used to stimulate and map the electrical activity within the heart and to ablate sites where abnormal electrical activity is detected. In use, an electrode catheter is inserted into a major vein or artery, such as the femoral vein, and then guided into the cardiac chamber of interest within the heart. A typical ablation procedure involves inserting a catheter having one or more electrodes at its distal end into the cardiac chamber. A reference electrode can generally be provided by taping it to the patient's skin or by a second catheter positioned within or near the heart. An RF (radiofrequency) current is applied through the tip electrode(s) of the ablation catheter, and current flows through the medium surrounding the tip electrode(s), i.e., blood and tissue, between the tip electrode(s) and an indifferent electrode. The distribution of the current depends on the amount of electrode surface in contact with the tissue as compared to blood, which has a higher conductivity than tissue. Heating of the tissue occurs due to the electrical resistance of the tissue. When the tissue is sufficiently heated, cell destruction is caused in the cardiac tissue, and as a result, a lesion is formed within the non-conductive cardiac tissue.

[0006] Irreversible electroporation (IRE) applies short electrical pulses that generate a sufficiently high electric field (typically exceeding 450 volts per centimeter) to irreversibly damage cells. Non-thermal IRE may be used in treating different types of tumors and other unwanted tissues without causing thermal damage to surrounding tissues. Small electrodes are placed in proximity to the target tissue to apply the short electrical pulses. The pulses increase the resting transmembrane potential and form nanopores within the plasma membrane. When the electricity applied to the tissue exceeds the electric field threshold of the target tissue, the cells become permanently permeable from the formation of the nanopores. As a result, the cells are unable to repair the damage due to the lack of homeostasis and die, and the cells typically die by apoptosis.

[0007] IRE may be used for cardiac ablation as an alternative to other cardiac ablation techniques, such as radiofrequency (RF) cardiac ablation. IRE cardiac ablation is sometimes referred to as pulsed-field ablation (PFA). Since IRE is generally a low-heat technique, IRE may reduce the risk of collateral cell damage that exists with other techniques, such as that which exists in RF cardiac ablation.

[0008] U.S. Patent Application Publication No. 2020 / 0069364 (Salahieh et al.) describes a cardiac tissue ablation catheter, which includes an inflatable and flexible toroidal or spherical balloon disposed in the distal region of an elongated member, and a flexible circuit carried by the outer surface of the balloon. The flexible circuit includes a plurality of flexible dendritic portions that conform to the radially outer surface of the balloon, and each of the plurality of flexible dendritic portions includes a substrate, a conductive trace carried by the substrate, and an ablation electrode carried by the substrate. The ablation electrode is in electrical communication with the conductive trace. The catheter also includes an elongated shaft extending within the elongated member, from the proximal region of the inflatable balloon to the distal region of the inflatable balloon, and having a guidewire lumen disposed within the inflatable balloon, wherein the distal region of the elongated shaft is directly or indirectly fixed to the distal region of the inflatable balloon.

[0009] U.S. Patent No. 8,295,902 (Salahieh et al.) describes a tissue electrode assembly that includes a membrane configured to form an expandable and conformable body deployable within a patient. The assembly further includes a flexible circuit disposed on the surface of the membrane and including at least one base substrate layer, at least one insulating layer, and at least one planar conductive layer. Conductive electrodes cover at least a portion of the flexible circuit and a portion of the surface of the membrane not covered by the flexible circuit, and the conductive electrodes can be folded with the membrane into a delivery configuration having a diameter suitable for minimally invasive delivery of the assembly to the patient.

[0010] U.S. Patent No. 10,470,682 (Deno et al.) describes a system for determining electrophysiological data. This system acquires electrophysiological signals from a plurality of electrodes of one or more catheters, selects at least one creek of the electrodes from the plurality of electrodes to determine a plurality of local E-field data points, determines the positions and orientations of the plurality of electrodes, processes the electrophysiological signals from at least one creek through the entire set of dipole sub-creeks to derive local E-field data points associated with at least one creek of the electrodes, derives at least one orientation-independent signal from at least one creek of the electrodes from the information content corresponding to the weighted portion of the potential map signal, and includes an electronic control unit configured to display or output catheter orientation-independent electrophysiological information to a user or process.

[0011] U.S. Patent Application Publication No. 2014 / 0200578 (Groff et al.) describes a medical device for ablating nerves around blood vessels, as well as methods of making and using the same. An exemplary medical device may include an expandable frame slidably disposed within a catheter shaft. The expandable frame may be configured to shift between a collapsed configuration and an expanded configuration. One or more electrodes may be disposed on the surface of the expandable frame. When the expandable frame is in the expanded configuration, the one or more electrodes may be disposed radially inwardly with respect to the maximum radial extent of the expandable frame.

[0012] U.S. Patent No. 6,004,269 (Crowley et al.) describes an acoustic imaging system for use within the heart, having a catheter, an ultrasonic device incorporated into the catheter, and electrodes mounted on the catheter. The ultrasonic device directs ultrasonic signals towards the internal structure of the heart to create an ultrasonic image, and the electrodes are arranged to make electrical contact with the internal structure. A chemical ablation device mounted on the catheter ablates at least a portion of the internal structure by delivering fluid thereto. The ablation device may include a material that vibrates in response to electrical excitation, and the ablation is at least assisted by the vibration of this material. The ablation device may alternatively be a transducer incorporated into the catheter that converts an electrical signal into radiation and is arranged to direct the radiation towards the internal structure. The electrodes may be ultrasonic structures incorporated into the catheter.

[0013] U.S. Patent Application Publication No. 2018 / 0125576 (Rubinstein et al.) describes a medical device including an elongated body and a distal portion coupled to the elongated body for use in acquiring the electrical activity of a patient's anatomical structure. The distal portion includes one or more expandable sections. Each expandable section has a plurality of electrodes disposed on one of (i) the outer surface of the one or more expandable sections, and (ii) the inner and outer surfaces of the one or more expandable sections. The one or more expandable sections, when expanded, bring a portion of the plurality of electrodes into contact with the surface of an organ and provide a path for physiological fluid to flow through the distal portion. In one embodiment, the distal portion is a tulip-shaped balloon distal portion. In another embodiment, the distal portion is an expandable distal portion having one or more concentrically wound expandable sections.

[0014] European Patent Publication No. 3576657 (A1) describes an electroporation system and method for energizing a catheter for realizing electroporation. The catheter for realizing electroporation includes a distal portion and an electrode assembly. The distal portion is configured to be disposed within a vein in the body. The vein defines a central axis. The electrode assembly is connected to the distal portion and includes a structure distributed around it and a plurality of electrodes. The structure is configured to at least partially contact the vein. Each of the electrodes is selectively energized to form a circumferential ring of energized electrodes concentric with the central axis of the vein. Summary of the Invention Means for Solving the Problems

[0015] According to an embodiment of the present invention, there is provided a medical system including a catheter configured to be inserted into a body part of a living subject, the catheter including a deflectable element having a distal end, an expandable distal end assembly disposed at the distal end of the deflectable element and including a plurality of assembly electrodes and configured to expand from a collapsed form to an expanded deployment form, a proximal electrode disposed proximal to the expandable distal end assembly at the distal end of the deflectable element and extending circumferentially around the deflectable element, and at least one electrical connection configured to electrically connect at least two of the assembly electrodes together so as to function as a composite assembly electrode. The medical system further includes an ablation power generator connected to the catheter and configured to apply an electrical signal between the composite assembly electrode and a selected electrode.

[0016] Furthermore, according to an embodiment of the present invention, the selected electrode is the proximal electrode.

[0017] Furthermore, according to an embodiment of the present invention, at least one electrical connection part permanently and electrically connects at least two assembly electrodes together so as to function as a composite assembly electrode.

[0018] In addition, according to an embodiment of the present invention, at least one electrical connection part is configured to electrically connect all of the assembly electrodes together so as to function as a composite assembly electrode.

[0019] Furthermore, according to an embodiment of the present disclosure, at least one electrical connection part permanently and electrically connects all of the assembly electrodes together so as to function as a composite assembly electrode.

[0020] Furthermore, according to an embodiment of the present disclosure, the expandable distal assembly includes at least one of an expandable basket including a plurality of splines with electrodes disposed on the splines, or an inflatable balloon with electrodes disposed on top.

[0021] Furthermore, according to an embodiment of the present disclosure, the proximal electrode includes a perfusion hole for perfusing a body part, and the catheter also includes a perfusion tube disposed within a deflectable element and configured to be in fluid communication with the perfusion hole of the proximal electrode.

[0022] In addition, according to an embodiment of the present invention, the perfusion holes are disposed radially around the proximal electrode.

[0023] Furthermore, according to an embodiment of the present invention, the perfusion holes are disposed longitudinally along the proximal electrode.

[0024] Furthermore, according to an embodiment of the present invention, the proximal electrode and the deflectable element define an annular hollow therebetween, and the perfusion tube is connected to transfer perfusate into the hollow, and the perfusion tube is in fluid communication with the perfusion holes through the hollow.

[0025] Furthermore, according to an embodiment of the present disclosure, the system includes a perfusion reservoir configured to store a perfusion fluid, and a pump connected to the perfusion reservoir and a catheter and configured to pump-transport the perfusion fluid from the perfusion reservoir through a perfusion hole and via a perfusion tube.

[0026] In addition, according to an embodiment of the present invention, the ablation power generator is configured to apply an electrical signal between the composite assembly electrode and the proximal electrode to perform electroporation of the tissue of the body part.

[0027] Furthermore, according to an embodiment of the present disclosure, the system includes a perfusion tube disposed within a deflectable element and configured to deliver a perfusion fluid into an area surrounded by an expandable distal end assembly.

[0028] Furthermore, according to an embodiment of the present invention, the proximal electrode has a maximum thickness measured perpendicular to the axis of the deflectable element of at least 0.05 mm and an inner diameter in the range of 2 mm to 6 mm.

[0029] Furthermore, according to an embodiment of the present invention, the proximal electrode and the distal end of the deflectable element define an annular region therebetween, and the catheter also includes a thermally conductive material disposed within the annular region, the thermally conductive material being formed from a material different from that of the proximal electrode.

[0030] Also, according to another embodiment of the present invention, there is provided a medical system comprising a catheter configured to be inserted into a body part of a living subject, the catheter including a deflectable element having a distal end, and an expandable distal end assembly disposed at the distal end of the deflectable element, the expandable distal end assembly including a plurality of assembly electrodes and being configured to expand from a collapsed form to an expanded deployment form, and at least one electrical connection portion that permanently electrically connects at least two of the assembly electrodes together so as to function as a composite assembly electrode. The medical system further includes an ablation power generator connected to the catheter and configured to apply an electrical signal to the composite assembly electrode to ablate tissue of the body part.

[0031] In addition, according to an embodiment of the present invention, at least one electrical connection portion permanently electrically connects all of the assembly electrodes together so as to function as a composite assembly electrode.

[0032] Furthermore, according to an embodiment of the present invention, the expandable distal end assembly includes at least one of an expandable basket including a plurality of splines with electrodes disposed on the splines, or an inflatable balloon with electrodes disposed on an upper portion thereof.

[0033] Furthermore, according to an embodiment of the present invention, the ablation power generator is configured to apply an electrical signal to the composite assembly electrode to perform electroporation of tissue of the body part. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be understood from the following detailed description in conjunction with the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0035] Overview A balloon catheter or another catheter having an expandable distal end assembly, such as a basket catheter, may include electrodes on the distal end assembly that can be used for ablation such as RF ablation or IRE ablation. To ablate a large area, the physician may need to reposition the catheter to adequately cover this area. This takes time.

[0036] Embodiments of the present invention solve the above problems by electrically connecting some or all of the electrodes of the distal end assembly of the catheter so as to function as a composite assembly electrode. An ablation power generator connected to the catheter applies an electrical signal to the composite assembly electrode to ablate (e.g., electroporate) tissue in a body part.

[0037] The return electrode can be used such that an ablation current is applied between the composite assembly electrode of the distal end assembly electrode and the return electrode. In some cases, if the return electrode is one of the electrodes on the distal end assembly or is at the center of the distal end assembly, the ablation current may avoid moving through the tissue, thereby reducing the effectiveness of the ablation current. Accordingly, in some embodiments, the catheter includes a proximal electrode disposed proximal to the distal end assembly. The ablation power generator applies an electrical signal between the composite assembly electrode and the proximal electrode to ablate (e.g., electroporate) tissue in a body part.

[0038] Placing the return electrode proximal to the expandable distal end assembly helps prevent the ablation current from moving inside the distal end assembly. However, due to the concentration of ablation energy at the proximal return electrode, the proximal return electrode may overheat or cause carbonization of the tissue.

[0039] Embodiments of the present invention solve the above problems by providing an irrigation proximal electrode disposed proximal to the distal end assembly at the distal end of the deflectable element of the catheter. The proximal electrode extends circumferentially around the deflectable element and includes irrigation holes for irrigating the body part to prevent overheating and carbonization. An irrigation tube disposed within the deflectable element is in fluid communication with the irrigation holes of the proximal electrode. The irrigation holes are generally disposed around and longitudinally along the proximal electrode.

[0040] In some embodiments, the proximal electrode and the deflectable element define an annular hollow therebetween, and the irrigation tube is connected to transfer irrigation fluid into the hollow, whereby the irrigation tube is in fluid communication with the irrigation holes through the hollow. The pump pumps the irrigation fluid from the irrigation reservoir through the irrigation tube into the hollow and out of the irrigation holes.

[0041] The ablation power generator is connected to the catheter and applies an electrical signal between the composite assembly electrode and the proximal electrode to perform radiofrequency (RF) ablation or electroporation of tissue in a body part.

[0042] In some embodiments, the expandable distal end assembly is also irrigated. A second irrigation tube is disposed within the deflectable element and can deliver irrigation fluid to the area surrounded by the expandable distal end assembly. In some embodiments, the electrodes of the expandable distal end assembly (e.g., balloon assembly) include irrigation holes that are in fluid communication with the second irrigation tube. In some embodiments, the irrigation of the expandable distal end assembly and the proximal electrode share the same irrigation tube.

[0043] In other embodiments, the proximal electrode is not irrigated. The distal end of the deflectable element and the proximal electrode define an annular region therebetween. A thermally conductive material is disposed within the annular region to dissipate heat from the tissue around the proximal electrode, thereby preventing or reducing overheating and carbonization. The thermally conductive material can be formed from a material different from that of the proximal electrode.

[0044] In other embodiments, the proximal electrode is formed from a thick piece of thermally conductive material to dissipate heat from the tissue around the proximal electrode, thereby preventing or reducing overheating and carbonization. In some embodiments, the proximal electrode has a maximum thickness of at least 0.05 mm measured perpendicular to the axis of the deflectable element and an inner diameter in the range of about 2 mm to 6 mm.

[0045] Description of the System Refer to FIG. 1, which is a schematic diagram of a medical system 20 constructed and operating in accordance with an exemplary embodiment of the present invention. The system 20 includes a catheter 40 configured to be inserted into a body part of a living subject (e.g., patient 28). Physician 30 uses a manipulator 32 near the proximal end of the catheter 40 and / or deflection from the sheath 23 to operate the elongate deflectable element 22 of the catheter 40 to direct the catheter 40 to a target location in the heart 26 of the patient 28. In the embodiment shown in the figure, physician 30 uses the catheter 40 to perform electroanatomical mapping of the heart chamber and ablation of the heart tissue.

[0046] The catheter 40 includes an expandable distal end assembly 35 (e.g., a basket assembly), which is inserted through the sheath 23 in a folded configuration and only after the catheter 40 exits the sheath 23 does the distal end assembly 35 assume its intended functional shape. By housing the distal end assembly 35 in a folded configuration, the sheath 23 also serves to minimize vascular trauma during the journey to the target location.

[0047] Catheter 40 includes a plurality of electrodes 48 disposed on an expandable distal end assembly 35 for sensing electrical activity and / or for applying ablation power to ablate tissue of a body part (insertion FIG. 25). Catheter 40 also includes a proximal electrode 21 disposed on a deflectable element 22 proximal to the expandable distal end assembly 35. Catheter 40 may incorporate a magnetic position sensor (not shown) at the distal edge of the deflectable element 22 (i.e., the proximal edge of the distal end assembly 35). Typically, but not necessarily, the magnetic sensor is a single-axis sensor (SAS). A second magnetic sensor (not shown) may be included at any suitable location on assembly 35. The second magnetic sensor may be, for example, a triaxial sensor (TAS), a dual-axis sensor (DAS), or an SAS, by way of example, taking into account size. The magnetic sensors, proximal electrode 21, and electrodes 48 disposed on assembly 35 are connected by wires extending through the deflectable element 22 to various drive circuits within console 24.

[0048] In some embodiments, system 20 includes a magnetic sensing subsystem that estimates the ellipticity and the expanded / retracted state of the basket assembly 35 of catheter 40 within a heart chamber of heart 26 by estimating the expansion of the basket assembly 35 from the distance between magnetic sensors. Patient 28 is placed within a magnetic field generated by a pad that includes one or more magnetic field generator coils 42 driven by unit 43. The magnetic field generated by coil(s) 42 transmits an alternating magnetic field to the region where the body part is located. The transmitted alternating magnetic field generates a signal within the magnetic sensors indicating position and / or orientation. The generated signal is transmitted to console 24 and serves as a corresponding electrical input to processing circuit 41.

[0049] Methods of sensing position and / or orientation using an external magnetic field and magnetic sensors are implemented in various medical applications, such as in the CARTO® system manufactured by Biosense-Webster, and are detailed in U.S. Patent Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, International Publication No. 96 / 05768, and U.S. Patent Application Publication Nos. 2002 / 0065455(A1), 2003 / 0120150(A1), and 2004 / 0068178(A1).

[0050] Typically a part of a general-purpose computer, processing circuit 41 is further connected via a suitable front-end and interface circuit 44 to receive signals from body surface electrodes 49. Processing circuit 41 is connected to body surface electrodes 49 by wires that extend through cable 39 to the chest of patient 28.

[0051] In one embodiment, processing circuit 41 renders at least a representation 31 of catheter 40 and the mapped body part on display 27 in response to the calculated position coordinates of catheter 40.

[0052] Processing circuit 41 is typically programmed with software to perform the functions described herein. The software can be downloaded electronically to the computer, for example, over a network, or alternatively or additionally, can be provided and / or stored on a non-transitory tangible medium, such as magnetic memory, optical memory, or electronic memory.

[0053] The medical system 20 may also include an ablation power generator 69 (such as an RF signal generator) configured to be connected to the catheter 40 and apply an electrical signal between one or more of the electrodes 48 and the proximal electrode 21. The medical system 20 may also include a perfusion reservoir 71 configured to store a perfusion fluid, and a pump 73 configured to be connected to the perfusion reservoir 71 and the catheter 40 and pump the perfusion fluid from the perfusion reservoir 71 through a perfusion tube and through the perfusion holes of the catheter 40, as will be described in more detail with reference to FIGS. 5A and 5B.

[0054] The illustration shown in FIG. 1 is selected merely for the purpose of making the concepts easier to understand. FIG. 1 shows only elements related to the disclosed techniques for simplicity and clarity. The system 20 typically includes additional modules and elements that are not directly related to the disclosed technology and are thus intentionally omitted from FIG. 1 and the corresponding description. The elements of the system 20 and the methods described herein may be further applied, for example, to control ablation of tissue of the heart 26.

[0055] Next, refer to FIGS. 2 and 3. FIG. 2 is a schematic diagram of the catheter 40 in a deployed configuration constructed and operating in accordance with an embodiment of the present invention. FIG. 3 is a schematic diagram of the distal end of the catheter 40 of FIG. 2 in a collapsed configuration.

[0056] Catheter 40 is configured to be inserted into a living subject's body part (e.g., heart 26 (FIG. 1)). The deflectable element 22 of catheter 40 has a distal end 33. The deflectable element 22 may be manufactured from any suitable material, such as polyurethane or polyether block amide. Assembly 35 is disposed distally of the deflectable element 22 and may be connected to the deflectable element 22 at the distal end 33 via a proximal coupling member 50. The proximal coupling member 50 typically includes a hollow tube and may be formed from any suitable material, such as, but not limited to, polycarbonate with or without a glass filler, polyetheretherketone (PEEK) with or without a glass filler, polyimide with or without a glass filler, polyamide, or polyetherimide (PEI). The coupling member 50 may be formed as an integral part of the deflectable element 22, or as part of the distal end assembly 35, or as a separate element that connects the deflectable element 22 and the distal end assembly 35.

[0057] Assembly 35, which may include a basket assembly, may include a plurality of splines, such as flexible strip 55 (only one is labeled for simplicity), and electrodes 48 are disposed on the splines. In the embodiments of FIGS. 2 and 3, each flexible strip 55 includes a single electrode 48 (only some are labeled for simplicity). Assembly 35 may include any suitable number of electrodes 48 having a plurality of electrodes 48 for each strip 55.

[0058] In the embodiments of FIGS. 2 and 3, each flexible strip 55 is formed of nitinol and is selectively coated with an insulating material (e.g., a shrink wrap (PET) of a thermoplastic polymer resin) within the distal and proximal regions 57 (only some are labeled for simplicity) of the flexible strip 55, leaving the central region 59 (only some are labeled for simplicity) of the flexible strip 55 as the electroactive region, to perform, for example, mapping and / or ablation or electroporation. The structure of the assembly 35 can be various. For example, the flexible strip 55 (or other spline) can include a flexible printed circuit board (PCB) or a shape memory alloy such as nitinol. The electroactive region of each flexible strip 55 can be larger or smaller than that shown in FIG. 2 and / or can be disposed more centrally or proximally on each flexible strip 55.

[0059] The embodiments described herein are by way of example only and mainly refer to the basket distal end assembly 35. In alternative embodiments, the disclosed techniques can be used with any other suitable type of distal end assembly.

[0060] The distal end assembly 35 includes a distal portion 61 and a proximal portion 63 and is configured to expand from a collapsed configuration (shown in FIG. 3) to an expanded deployed configuration (shown in FIG. 2). The relaxed state of the distal end assembly 35 is the expanded deployed configuration shown in FIG. 2. The distal end assembly 35 is configured to collapse into a collapsed configuration when the catheter 40 is stored within the sheath 23 (FIG. 1) and to expand into an expanded deployed configuration when the catheter 40 is removed from the sheath 23. The relaxed shape of the distal end assembly 35 can be set by forming the flexible strip 55 from any suitable elastic material such as nitinol or PEI. In some embodiments, the relaxed state of the expandable distal end assembly 35 can be a collapsed configuration, and the expandable distal end assembly 35 is connected to the distal portion 61 and is expanded using a pull wire or element supplied through a lumen within the deflectable element 22.

[0061] The proximal electrode 21 is disposed proximal to an expandable distal end assembly 35 at the distal end 33 of the deflectable element 22 and generally extends circumferentially around the deflectable element 22. The proximal electrode 21 includes irrigation holes 65 (only some are labeled for simplicity) for irrigating a body part. The irrigation holes 65 are generally disposed around and / or longitudinally along the proximal electrode 21. The irrigation holes may have any suitable diameter, for example, within the range of 25 to 100 micrometers. The holes may be formed using any suitable technique, such as laser drilling or electrical discharge machining (EDM). The proximal electrode 21 may include any suitable number of holes, for example, within the range of 4 to 100. In one example, the proximal electrode 21 includes five proximally disposed holes and five distally disposed holes. An additional irrigation tube 85 is disposed within the element 22, as will be described in more detail subsequently.

[0062] An ablation power generator 69 (FIG. 1) is connected to the catheter 40 and configured to apply an electrical signal between at least one of the electrodes 48 and the proximal electrode 21. In some embodiments, the ablation power generator 69 is configured to apply an electrical signal between at least one of the electrodes 48 and the proximal electrode 21 to effect electroporation of tissue of a body part.

[0063] Referring now to FIGS. 4A and 4B. FIG. 4A is a cross-sectional view of the distal end of the catheter 40 of FIG. 2. FIG. 4B is a more detailed cross-sectional view of the distal end of the catheter 40 inside block B of FIG. 4A.

[0064] The distal ends of the flexible strips 55 (only two are labeled for simplicity) are, in some embodiments, folded over and connected to a distal connector 75 that is a tube (e.g., a polymer tube) or a slug (e.g., a polymer slug). The distal connector 75 may be formed of any suitable material, such as, but not limited to, polycarbonate with or without a glass filler, PEEK with or without a glass filler, or PEI with or without a glass filler. In some embodiments, the flexible strip 55 may be connected to the distal connector 75 without being folded such that when the distal end assembly 35 is crushed, the flexible strip 55 approaches a flat formation along its length. The proximal end of the flexible strip 55 is connected to a proximal coupling member 50. The flexible strip 55 may be connected to the distal connector 75 and the proximal coupling member 50 using a suitable adhesive such as an epoxy adhesive.

[0065] In some embodiments, the catheter 40 includes a nose cap 77 inserted into the distal connector 75. The nose cap 77 may be used to assist in fixing the flexible strip 55 to the distal connector 75. The nose cap 77 may be formed of any suitable material such as, but not limited to, polycarbonate with or without a glass filler, PEEK with or without a glass filler, or PEI with or without a glass filler. The nose cap 77 may optionally be sized to provide a press fit against the flexible strip 55 to prevent the flexible strip 55 from being pulled away from the inner surface of the distal connector 75.

[0066] In some embodiments, the thickness of the distal portion of the flexible strip 55 can be reduced (compared to the rest of the flexible strip 55) to provide a hinge 79 (one hinge 79 per flexible strip 55), allowing the flexible strip 55 to bend sufficiently between the collapsed form and the deployed and expanded form of the expandable distal end assembly 35. For simplicity purposes, only two of the hinges 79 are labeled. The hinge 79 of the flexible strip 55 may be reinforced using a flexible material such as a thread (not shown). The hinge 79 (including the thread and the coating layer) may have any suitable thickness in the range of, for example, about 10 to 140 micrometers. The thread may include any one or more of ultra-high molecular weight polyethylene threads or threads spun from liquid crystal polymers. The thread may have any suitable linear density in the range of, for example, about 25 denier to 250 denier.

[0067] Now, refer to FIGS. 5A and 5B. FIG. 5A is a cross-sectional view of the catheter 40 of FIG. 2 taken along line A:A. FIG. 5B is a cross-sectional view of the catheter of FIG. 2 taken along line B:B.

[0068] FIGS. 5A and 5B show a proximal electrode 21 extending circumferentially around the deflectable element 22. The edges of the proximal electrode 21 may be connected to the deflectable element 22 using a suitable adhesive and / or using a covering such as a shrink wrap of a thermoplastic polymer resin. FIGS. 5A and 5B show a portion of the perfusion holes 65 (only some are labeled for simplicity) within the proximal electrode 21. The proximal electrode 21 may have any suitable length in the range of, for example, about 2 to 10 mm, measured parallel to the elongation direction of the deflectable element 22.

[0069] The catheter 40 includes a perfusion tube 81 disposed within the deflectable element 22 and configured to be in fluid communication with the perfusion holes 65 of the proximal electrode 21. A pump 73 (FIG. 1) is connected to the perfusion reservoir 71 (FIG. 1) and the catheter 40 and is configured to pump perfusion fluid from the perfusion reservoir 71 through the perfusion holes 65 and via the perfusion tube 81.

[0070] The inner surface of the proximal electrode 21 and the deflectable element 22 define an annular cavity 83 therebetween. The infusion tube 81 is connected to the annular cavity 83 to transfer infusion fluid into the cavity 83. The infusion tube 81 is generally disposed at the other side of the annular cavity 83 at the infusion hole 65. Thus, the infusion tube 81 is in fluid communication with the infusion hole 65 via the cavity 83. The pump 73 (FIG. 1) is configured to pump the infusion fluid from the infusion reservoir 71 through the infusion tube 81 into the cavity 83 and out of the infusion hole 65. The collection of the infusion fluid within the annular cavity 83 acts to cool not only the portion near the infusion hole 65 but also the outer surface of the proximal electrode 21.

[0071] The catheter 40 may include another infusion tube 85 that is disposed within the deflectable element 22 and configured to deliver the infusion fluid to a region 87 (FIG. 2) surrounded by the flexible strip 55 of the expandable distal end assembly 35. The infusion tube 85 typically extends within the expandable distal end assembly 35 as shown in FIGS. 2 and 3.

[0072] In some embodiments, the catheter 40 includes a position sensor 89 (such as a magnetic position sensor) disposed within the deflectable element 22. FIGS. 5A and 5B also show wires 91 disposed internally to connect the electrodes 48, the proximal electrode 21, and the position sensor 89 to the proximal end of the catheter 40.

[0073] Next, refer to FIG. 6, which is a schematic view of a deployed catheter 100 constructed and operating in accordance with an alternative embodiment of the present invention. The catheter 100 is substantially the same as the catheter 40 of FIGS. 2 and 3, except for the following differences. The catheter 100 includes a non-infused proximal electrode 106. The proximal electrode 106 may be cooled by filling it with a thermally conductive material as described with reference to the proximal electrode 106-1 in FIG. 7, or by forming the proximal electrode from a thermally conductive material having a thickness sufficient to dissipate heat as described with reference to the proximal electrode 106-2 in FIG. 8.

[0074] Now, refer to FIG. 7, which is a cross-sectional view of catheter 100 of FIG. 6 along line C:C. The proximal electrode 106-1 and the distal end of the deflectable element 22 define an annular region 102 therebetween. The catheter 100 is disposed within the annular region 102 and includes a thermally conductive material 104 that, although not essential, generally fills the annular region 102 and generally contacts at least a portion of the inner surface of the proximal electrode 106-1. The thermally conductive material 104 may be formed from a material different from that of the proximal electrode 106-1.

[0075] As used herein and in the claims, the term "thermally conductive material" is defined as a material having a thermal conductivity of 1 watt per meter kelvin (W / mK) or more at 25 degrees Celsius. The thermally conductive material 104 may be any suitable thermally conductive material such as, for example, but not limited to, platinum, palladium, gold, or a thermally conductive epoxy. In some embodiments, the thermally conductive material 104 is first wound around the outer surface of the deflectable element 22, and then the proximal electrode 106-1 is wound around the thermally conductive material 104. In other embodiments, the proximal electrode 106-1 (either as a single piece or as two halves that are later joined together integrally) is first fixed around the deflectable element 22, and then the thermally conductive material 104 is injected under the proximal electrode 106-1 through a hole (not shown) in the proximal electrode 106-1.

[0076] The wall thickness of the proximal electrode 106-1 may have any suitable value in the range of, for example, about 0.01 mm to about 0.25 mm. The thickness of the thermally conductive material 104 may have any suitable value in the range of, for example, about 0.01 mm to 0.25 mm. The proximal electrode 106-1 may have any suitable length, for example, in the range of about 2 mm to 10 mm, measured parallel to the longitudinal direction of the deflectable element 22.

[0077] Note that the irrigation tube 81 (FIGS. 5A and 5B) is not included within the deflectable element 22 shown in FIG. 7.

[0078] Referring now to FIG. 8, which is a cross-sectional view of catheter 100 of FIG. 6 taken along line C:C, constructed and operative in accordance with another alternative embodiment of the present invention. The proximal electrode 106-2 shown in FIG. 8 has a wall thickness greater than that of the proximal electrode 106-1 described with reference to FIG. 7.

[0079] The proximal electrode 106-2 may have any suitable wall thickness. In some embodiments, the proximal electrode 106-2 may have a maximum thickness measured perpendicular to the axis of the deflectable element 22 of at least 0.05 mm and an inner diameter in the range of 2 mm to 6 mm.

[0080] The proximal electrode 106-2 may have any suitable length measured parallel to the elongation direction of the deflectable element 22 of about 2 to 10 mm.

[0081] The proximal electrode 106-2 is formed from a thermally conductive material that provides dissipation of heat formed during electroporation and / or RF ablation. The thermally conductive material may be any suitable thermally conductive material, for example, but not limited to, platinum, palladium, or gold.

[0082] Each proximal electrode 106-2 may be formed as a flat electrode wound around the outer surface of the deflectable element 22 to form a ring, or as two half-rings connected together around the deflectable element 22.

[0083] Each of the proximal electrodes 106-2, 106-1 (FIG. 7), 21 (FIGS. 5A and 5B) has a non-uniform surface that bulges away from the outer surface of the deflectable element 22. The proximal electrode may have any suitable shape. For example, the proximal electrodes 21, 106-1, 106-2 may be formed as rings having a uniform outer diameter along the length of the proximal electrode 21.

[0084] Next, refer to FIG. 9, which is a schematic diagram of an inflated balloon catheter 200 constructed and operating in accordance with yet another alternative embodiment of the present invention. The catheter 200 is substantially the same as the catheter 40 of FIG. 2, except that the catheter 200 includes an inflatable distal end assembly 202 that includes an inflatable balloon 204 (only some are labeled for simplicity) with electrodes 206 disposed at the top. The catheter 200 includes an infusion tube 208 disposed within a deflectable element 22 and extending into a region 210 surrounded by the inflatable balloon 204. The electrodes 206 of the expandable distal end assembly 202 include infusion holes 212 (only some are labeled for simplicity) that are in fluid communication with the infusion tube 208. The catheter 200 includes a proximal electrode 214 that is substantially the same configuration as the proximal electrode 21 described with reference to FIGS. 5A and 5B. In some embodiments, the proximal electrode 214 may be replaced with the proximal electrode 106-1 of FIG. 7, or the proximal electrode 106-2 of FIG. 8.

[0085] Now, refer to FIG. 10, which is a schematic diagram of electrode connections in a catheter 40 of a medical system 20 constructed and operating in accordance with an exemplary embodiment of the present invention.

[0086] The catheter 40 may include one or more electrical connections 230 configured to electrically connect together at least two (and optionally all) of the assembly electrodes 48 so as to function as a composite assembly electrode 232.

[0087] In some embodiments, the electrical connection(s) 230 are configured to selectively connect the assembly electrodes 48 together so as to function as a composite assembly electrode 232, and also to allow the electrodes 48 to function as individual electrodes, for example, for detection positions, electrical activation, and performing individual ablations. In such embodiments, the electrical connection 230 may include a switching circuit (not shown) that enables selectively connecting together two or more (and optionally all) of the assembly electrodes 48.

[0088] In other embodiments, the electrical connection(s) 230 permanently electrically connect(s) at least two (and optionally all) of the assembly electrodes 48 together to function as a composite assembly electrode 232.

[0089] The ablation power generator 69 is connected to the catheter 40 and configured to apply an electrical signal (arrow 234) to the composite assembly electrode 232 to ablate tissue of a body part. In some embodiments, the ablation power generator 69 is configured to apply the electrical signal 234 to the composite assembly electrode 48 to perform electroporation of the tissue of the body part.

[0090] The electrical signal 234 is generally applied between the composite assembly electrode 232 and a return electrode. The return electrode may be disposed at any suitable location, such as on the catheter 40, as an indifferent electrode attached to the patient's skin, or on another catheter. In some embodiments, the proximal electrode 21 functions as the return electrode.

[0091] Thus, in some embodiments, the ablation power generator 69 is configured to apply an electrical signal between the composite assembly electrode 232 and the proximal electrode 21. In some embodiments, the ablation power generator 69 is configured to apply an electrical signal between the composite assembly electrode 232 and the proximal electrode 21 to perform electroporation of the tissue of the body part.

[0092] As described above, ablation can cause excessive heating within the region of the proximal electrode 21. Thus, the proximal electrode 21 may apply cooling to the surrounding tissue using perfusion as described above with reference to FIGS. 2, 5A, and 5B.

[0093] The electrical connection 230 may be implemented using another catheter for connecting the assembly electrodes together to form the composite assembly electrode.

[0094] In some embodiments, two or more (and optionally all) of the assembly electrodes 48 (FIG. 6) of the catheter 100 may be (optionally or permanently) connected using the electrical connection 230. The proximal electrode 106 (FIG. 6) or any other suitable electrode may function as a return electrode. The proximal electrode 106 can provide cooling using the thermally conductive material 104 disposed within the annular region 102 (FIG. 7) of the proximal electrode 106, as described in more detail above with reference to FIG. 7. Alternatively, the proximal electrode 106 may provide cooling by forming the proximal electrode 106 (FIG. 8) from a thermally conductive material having a maximum thickness, measured perpendicular to the axis of the deflectable element, of at least 0.05 mm and an inner diameter in the range of 2 mm to 6 mm, as described in more detail above with reference to FIG. 8.

[0095] In some embodiments, two or more (and optionally all) of the electrodes 206 of the expandable distal end assembly 202 of the catheter 200 of FIG. 9 may be (optionally or permanently) connected using the electrical connection 230. The proximal electrode 214 (FIG. 9) or any other suitable electrode may function as a return electrode.

[0096] As used herein, the terms “about” or “approximately” with respect to any numerical value or range of numerical values indicate a tolerable error in dimensions suitable to enable a component part or collection of components to function in accordance with its intended purpose as described herein. More specifically, “about” or “approximately” can refer to a range of values that are ±20% of the recited value, for example, “about 90%” can refer to a range of values from 72% to 108%.

[0097] Although the various features of the present invention are described in the context of separate embodiments for clarity, these may also be provided in combination in a single embodiment. Conversely, the various features of the present invention described in the context of a single embodiment for brevity may be provided separately or in any suitable partial combination.

[0098] The above embodiments are cited as examples, and the present invention is not limited to those specifically illustrated and described in the above specification. Rather, the scope of the present invention includes both the combinations of various features described in the above specification and their partial combinations, as well as those modifications and variations that are not disclosed in the prior art and would be conceived by those skilled in the art upon reading the above description.

[0099] 〔Embodiment〕 (1) A medical system, A catheter configured to be inserted into a body part of a living subject, A deflectable element having a distal end, An expandable distal end assembly disposed at the distal end of the deflectable element, including a plurality of assembly electrodes and configured to expand from a collapsed form to an expanded deployment form, A proximal electrode disposed proximal to the expandable distal end assembly at the distal end of the deflectable element and extending circumferentially around the deflectable element, At least one electrical connection portion configured to electrically connect at least two of the assembly electrodes together so as to function as a composite assembly electrode, and a catheter including the same, An ablation power generator connected to the catheter and configured to apply an electrical signal between the composite assembly electrode and a selected electrode. A medical system comprising the same. (2) The system according to Embodiment 1, wherein the selected electrode is the proximal electrode. (3) The system according to Embodiment 1, wherein the at least one electrical connection portion permanently electrically connects the at least two assembly electrodes together so as to function as the composite assembly electrode. (4) The system according to Embodiment 1, wherein the at least one electrical connection portion is configured to electrically connect all of the assembly electrodes together so as to function as the composite assembly electrode. (5) The system according to embodiment 4, wherein the at least one electrical connection portion permanently and electrically connects all of the assembly electrodes together so as to function as the composite assembly electrode.

[0100] (6) The system according to embodiment 1, wherein the expandable distal assembly includes at least one of an expandable basket having a plurality of splines with the electrodes disposed on the splines, or an inflatable balloon having the electrodes disposed thereon. (7) The system according to embodiment 1, wherein the proximal electrode includes a perfusion hole for perfusing the body part, and the catheter further includes a perfusion tube disposed within the deflectable element and configured to be in fluid communication with the perfusion hole of the proximal electrode. (8) The system according to embodiment 7, wherein the perfusion holes are disposed radially around the proximal electrode. (9) The system according to embodiment 8, wherein the perfusion holes are disposed longitudinally along the proximal electrode. (10) The system according to embodiment 7, wherein the proximal electrode and the deflectable element define an annular hollow therebetween, and the perfusion tube is connected to transfer perfusate into the hollow and is in fluid communication with the perfusion hole through the hollow.

[0101] (11) A perfusion reservoir configured to store perfusate, and a pump connected to the perfusion reservoir and the catheter and configured to pump the perfusate from the perfusion reservoir through the perfusion hole and via the perfusion tube. The system according to embodiment 7 further includes the pump. (12) The system according to embodiment 1, wherein the ablation power generator is configured to apply the electrical signal between the composite assembly electrode and the proximal electrode to effect electroporation of tissue of the body part. The system according to embodiment 1, further comprising an irrigation tube disposed within the deflectable element and configured to deliver irrigation fluid into an area surrounded by the expandable distal end assembly. (14) The system according to embodiment 1, wherein the proximal electrode has a maximum thickness measured perpendicular to the axis of the deflectable element of at least 0.05 mm and an inner diameter in the range of 2 mm to 6 mm. (15) The distal end of the proximal electrode and the deflectable element define an annular region therebetween, and the catheter also includes a thermally conductive material disposed within the annular region, the thermally conductive material being formed from a material different from that of the proximal electrode. The system according to embodiment 1.

[0102] (16) A medical system, A catheter configured to be inserted into a body part of a living subject, A deflectable element having a distal end, An expandable distal end assembly disposed at the distal end of the deflectable element, including a plurality of assembly electrodes and configured to expand from a collapsed form to an expanded deployed form, At least one electrical connection that permanently electrically connects at least two of the assembly electrodes together to function as a composite assembly electrode. A catheter comprising, An ablation power generator connected to the catheter and configured to apply an electrical signal to the composite assembly electrode to ablate tissue of the body part. A medical system comprising. (17) The system according to embodiment 16, wherein the at least one electrical connection permanently electrically connects all of the assembly electrodes together to function as the composite assembly electrode. (18) The system according to embodiment 16, wherein the expandable distal assembly includes at least one of: an expandable basket having a plurality of splines with the electrodes disposed on the splines; or an inflatable balloon having the electrodes disposed thereon. (19) The system according to embodiment 16, wherein the ablation power generator is configured to apply the electrical signal to the composite assembly electrode to effect electroporation of tissue of the body part.

Claims

1. A medical system, a catheter configured to be inserted into a body part of a living subject, a deflectable element having a distal end, an expandable distal end assembly disposed at the distal end of the deflectable element, including a plurality of assembly electrodes and configured to expand from a collapsed form to an expanded deployment form, a proximal electrode disposed proximal to the expandable distal end assembly on the deflectable element and extending circumferentially around the deflectable element, at least one electrical connection configured to electrically connect at least two of the assembly electrodes together so as to function as a composite assembly electrode, and a catheter including the same, an ablation power generator connected to the catheter and configured to apply a current between the composite assembly electrode and a selected electrode, wherein the selected electrode is the proximal electrode, the proximal electrode and the deflectable element define an annular region therebetween, and the catheter includes a thermally conductive material disposed within the annular region, the thermally conductive material being formed from a material different from that of the proximal electrode, the thermally conductive material is a material having a thermal conductivity of 1 watt per meter kelvin (W / mK) or more at 25 degrees Celsius. A system.

2. The system according to claim 1, wherein the thermally conductive material is platinum, palladium, gold, a thermally conductive epoxy, or any combination thereof.

3. The system according to claim 1, wherein the at least one electrical connection electrically connects the at least two assembly electrodes together so as to function as a composite assembly electrode.

4. The system according to claim 1, wherein the at least one electrical connection is configured to electrically connect all of the assembly electrodes together so as to function as a composite assembly electrode.

5. The system according to claim 4, wherein the at least one electrical connection electrically connects all of the assembly electrodes together so as to function as a composite assembly electrode.

6. The system of claim 1, wherein the expandable distal assembly comprises at least one of an expandable basket having a plurality of splines with the assembly electrodes disposed on the splines, or an inflatable balloon having the assembly electrodes disposed thereon.

7. The system of claim 1, wherein the proximal electrode includes irrigation holes for irrigating the body part, and the catheter further includes an irrigation tube disposed within the deflectable element and configured to be in fluid communication with the irrigation holes of the proximal electrode.

8. The system of claim 7, wherein the irrigation holes are disposed radially around the proximal electrode.

9. The system of claim 8, wherein the irrigation holes are disposed longitudinally along the proximal electrode.

10. The system of claim 7, wherein the proximal electrode and the deflectable element define an annular hollow therebetween, and the irrigation tube is connected to transfer irrigation fluid into the annular hollow and is in fluid communication with the irrigation holes through the annular hollow.

11. An irrigation reservoir configured to store irrigation fluid, The system of claim 7, further comprising a pump connected to the irrigation reservoir and the catheter and configured to pump the irrigation fluid from the irrigation reservoir through the irrigation holes via the irrigation tube.

12. The system of claim 1, wherein the ablation power generator is configured to apply the current between the composite assembly electrode and the proximal electrode to perform electroporation of the tissue of the body part.

13. The system of claim 1, further comprising an irrigation tube disposed within the deflectable element and configured to deliver irrigation fluid into an area surrounded by the expandable distal assembly.

14. The system of claim 1, wherein the proximal electrode has a maximum thickness of at least 0.05 mm measured perpendicular to the axis of the deflectable element and an inner diameter in the range of 2 mm to 6 mm.

15. A medical system, A catheter configured to be inserted into a body part of a living subject, A deflectable element having a distal end, An expandable distal end assembly disposed at the distal end of the deflectable element, including a plurality of assembly electrodes and configured to expand from a collapsed form to an expanded form. A proximal electrode disposed proximally to the expandable distal end assembly on the deflectable element and extending circumferentially around the deflectable element. At least one electrical connection portion for electrically connecting at least two of the assembly electrodes together so as to function as a composite assembly electrode, and a catheter. An ablation power generator connected to the catheter and configured to apply a current to the composite assembly electrode to ablate the tissue of the body part. The proximal electrode and the deflectable element define an annular region therebetween, and the catheter includes a thermally conductive material disposed within the annular region, the thermally conductive material being formed from a material different from that of the proximal electrode. The system wherein the thermally conductive material is a material having a thermal conductivity of 1 watt per meter kelvin (W / mK) or more at 25 degrees Celsius.

16. The system according to claim 15, wherein the thermally conductive material is platinum, palladium, gold, a thermally conductive epoxy, or any combination thereof.

17. The system according to claim 15, wherein the at least one electrical connection portion electrically connects all of the assembly electrodes together so as to function as the composite assembly electrode.

18. The system according to claim 15, wherein the expandable distal end assembly includes at least one of an expandable basket having a plurality of splines, the assembly electrodes being disposed on the splines, or an inflatable balloon having the assembly electrodes disposed thereon.

19. The system according to claim 15, wherein the ablation power generator is configured to apply the current to the composite assembly electrode to perform electroporation of the tissue of the body part.

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