Basket catheter with a mushroom-shaped distal tip

Abstract

To provide a medical probe.SOLUTION: Embodiments of the present invention include a medical probe having an insertion tube, a basket assembly, an axial electrode, and a plurality of radial electrodes. The insertion tube is configured for insertion into a body cavity of a patient. The basket assembly has a proximal end that is connected distally to the insertion tube and includes a plurality of resilient spines, which are configured to bow radially outward from an axis of the basket assembly and are conjoined at a distal end of the basket assembly. The axial electrode is disposed at the distal end of the basket assembly, having a diameter of at least 1.5 millimeters, and is configured to contact tissue in the body cavity. The radial electrodes are configured to contact the tissue in the body cavity and include radial electrodes disposed on the spines.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention generally relates to medical probes, and more particularly to a medical probe comprising a mushroom-shaped ablation electrode attached to the distal end of a basket assembly.

Background Art

[0002] Arrhythmia is typically an abnormal heartbeat rhythm caused by a small area of heart tissue that causes an irregular heartbeat. Cardiac ablation is a medical procedure that can be performed to treat arrhythmia by destroying the area of heart tissue that causes the irregular heartbeat. Some medical systems use irreversible electroporation (IRE) to ablate heart tissue. IRE is a non-thermal ablation method based on the irreversible permeabilization of cell membranes caused by high-voltage short pulses delivered to the tissue.

[0003] U.S. Patent Application No. 2016 / 0113582 to Altmann et al. describes a catheter having a distal tip with a microelectrode array that can be used for acute focal mapping. The catheter includes a basket assembly having a plurality of electrode-bearing spines. The distal tip has a non-metallic electrical insulating substrate body with a recess, and within the recess, microelectrodes are positioned to exhibit a generally smooth distal tip contour.

[0004] U.S. Patent Application No. 2012 / 0143298 to Just et al. describes an electrode assembly for a catheter. In one embodiment, the electrode assembly includes one or more positioning electrodes and one or more ablation electrodes disposed at the distal end of a shaft. In another embodiment, the electrode assembly includes a basket portion of a catheter having non-contact electrodes.

[0005] Ruppersber's U.S. Patent Application No. 2018 / 0279896 describes a system and method for analyzing electrophysiological data. The system comprises an ablation module configured to deliver RF ablation energy to an ablation electrode positioned near the distal end of a catheter. In one embodiment, the system comprises a catheter having an elongated body, including a tip electrode and a ground electrode, which are electrically insulated from each other and can be used for electroablation of body tissue.

[0006] Kordis et al., U.S. Patent Application No. 2014 / 0303469, describes a method for detecting cardiac rhythm disorders. The system uses a catheter comprising a basket assembly having spines used to guide multiple exposed electrodes configured to sense local voltages from the endocardial surface of the heart.

[0007] Govari's U.S. Patent Application No. 2018 / 0344188 describes a catheter comprising a basket assembly. The basket assembly comprises multiple spline electrodes arranged on splines of the assembly, with a far-field electrode located inside the assembly. The spline electrodes can be used to generate an intracardiac electrogram, and the far-field electrode can be used to generate a far-field electrogram.

[0008] The above description is provided as a general overview of the relevant technologies in the field and should not be construed as constituting prior art for this patent application in any way. [Overview of the Initiative] [Means for solving the problem]

[0009] According to one embodiment of the present invention, a medical probe is provided, which includes an insertion tube configured to be inserted into a patient's body cavity; a basket assembly having a proximal end distally connected to the insertion tube and including a plurality of elastic spines, wherein the elastic spines are configured to curve radially outward from the axis of the basket assembly and are coupled at the distal end of the basket assembly; an axial electrode located at the distal end of the basket assembly, having a diameter of at least 1.5 millimeters and configured to contact tissue in the body cavity; and a plurality of radial electrodes, including radial electrodes located on the spines and configured to contact tissue in the body cavity.

[0010] In one embodiment, the medical probe further includes an electrical signal generator connected to an axial electrode and a radial electrode.

[0011] In another embodiment, the electrical signal generator is configured to deliver irreversible electroporation (IRE) pulses to the axial electrode. In some embodiments, the electrical signal generator is configured to deliver IRE energy simultaneously to the axial electrode and at least one radial electrode. In other embodiments, the electrical signal generator is configured to deliver radio frequency energy to the axial electrode.

[0012] In additional embodiments, the spine has an external side and an internal side, and each given radial electrode includes a conductive material biased toward the external side of its respective spine.

[0013] In further embodiments, the axial electrode is circular in shape with a rounded surface. In some embodiments, the axial electrode has a thickness of at least 20% of its diameter. In other embodiments, the axial electrode has sides with a radius of curvature of at least 25% of its thickness. In supplemental embodiments, the axial electrode has sides with a radius of curvature of up to 50% of its thickness.

[0014] One embodiment of the present invention provides a method for manufacturing a medical probe, the method comprising: providing an insertion tube configured to be inserted into a patient's body cavity; providing a basket assembly having a proximal end distally connected to the insertion tube and comprising a plurality of elastic spines, wherein the elastic spines are configured to curve radially outward from the axis of the basket assembly and are coupled at the distal end of the basket assembly; providing an axial electrode positioned at the distal end of the basket assembly, having a diameter of at least 1.5 millimeters, and configured to contact tissue in the body cavity; and providing a plurality of radial electrodes, comprising radial electrodes positioned on the spines and configured to contact tissue in the body cavity.

[0015] According to one embodiment of the present invention, a treatment method is further provided, which includes inserting an insertion tube into a body cavity having a distal end containing a lumen through which the insertion tube penetrates; deploying a basket assembly into the body cavity from the distal end, having a proximal end distally connected to the insertion tube and including a plurality of elastic spines, wherein the elastic spines are configured to curve radially outward from the axis of the basket assembly and are coupled at the distal end of the basket assembly, and the basket assembly includes an axial electrode positioned at the distal end of the basket assembly, having a diameter of at least 1.5 millimeters and configured to contact tissue in the body cavity, and a plurality of radial electrodes configured to contact tissue in the body cavity and positioned on the spines; positioning the basket assembly so that the axial electrodes compress tissue in the body cavity; and transmitting ablation energy to the tissue via the axial electrodes. [Brief explanation of the drawing]

[0016] In this specification, the present disclosure will be described with reference to the accompanying drawings, which are provided as examples only. [Figure 1]This is a schematic drawing of a medical system 20 according to one embodiment of the present invention, which includes an axial electrode fixed to the distal end of a basket assembly. [Figure 2] This is a schematic diagram of an expanded basket assembly according to one embodiment of the present invention. [Figure 3] This is a schematic lateral view of an axial electrode according to one embodiment of the present invention. [Figure 4] This is a schematic side view of an axial electrode according to one embodiment of the present invention. [Figure 5] This is a schematic side view of a folded basket assembly according to one embodiment of the present invention. [Figure 6] This flowchart schematically illustrates a method for performing a tissue ablation medical procedure in the cardiac chamber using axial electrodes according to one embodiment of the present invention. [Figure 7] This is a schematic drawing of a basket assembly inside the cardiac chamber during a medical procedure, according to one embodiment of the present invention. [Figure 8] This is a schematic drawing of a basket assembly inside the cardiac chamber during a medical procedure, according to one embodiment of the present invention. [Modes for carrying out the invention]

[0017] overview While the distal tip of a basket catheter can be equipped with a diagnostic electrode, limitations on electrode size make it difficult to operate the electrode as an ablation electrode. In contrast to diagnostic electrodes, ablation electrodes must support the transmission of relatively large currents without damage or deformation, and must have sufficient surface area and shape to avoid high current densities that could generate localized electric arcs.

[0018] Embodiments of the present invention provide a medical probe comprising a basket assembly having an ablation electrode fixed to its distal end. As described below, the medical probe comprises an insertion tube configured to be inserted into a patient's body cavity and a basket assembly distally connected to the insertion tube, i.e., having a proximal end connected distally to the insertion tube. The basket assembly comprises a plurality of elastic spines configured to curve radially outwardly from the axis of the basket assembly and joined at the distal end of the basket assembly. The medical probe further comprises an axial electrode disposed at the distal end of the basket assembly, having a diameter of at least 1.5 millimeters (mm), and configured to contact tissue within the body cavity. In addition to the axial electrode, the medical probe further comprises a plurality of radial electrodes configured to contact tissue within the body cavity and disposed on the spines.

[0019] In some embodiments, the axial electrode is mushroom-shaped (i.e., a thick disk having a rounded surface) and has a contact area large enough to provide a lateral surface area sufficient to dissipate heat during an ablation procedure (i.e., for the at least 1.5 mm described above). In addition to increasing the surface area, the rounded surface of the axial electrode helps prevent arcing and does not damage the tissue.

[0020] Description of the System FIG. 1 is a schematic drawing of a medical system 20 including a medical probe 22 and a control console 24, according to an embodiment of the present invention. The medical system 20 can be based, for example, on the CARTO® system manufactured by Biosense Webster Inc. (31 Technology Drive, Suite 200, Irvine, CA 92618 USA). In the embodiment described below, the medical probe 22 can be used for diagnostic or therapeutic procedures, such as performing an ablation procedure on the heart 26 of a patient 28. Alternatively, the medical probe 22 can be used for other therapeutic and / or diagnostic purposes in the heart or other body organs with the necessary modifications.

[0021] The probe 22 includes a flexible insertion sheath 30 and a handle 32 coupled to the proximal end of the insertion sheath. The probe 22 also includes a flexible insertion tube 74 housed within the insertion sheath 30. During a medical procedure, a medical professional 34 can insert the probe 22 through the patient's 28 vasculature such that the distal end 36 of the insertion sheath 30 enters a body cavity, such as a chamber of the heart 26. When the distal end 36 enters a chamber of the heart 26, the medical professional 34 can deploy a basket assembly 38 attached to the distal end 73 of the insertion tube 74. The basket assembly 38 includes a set of electrodes 40, as described in the description referring to FIG. 2 below.

[0022] To initiate a medical procedure, such as an irreversible electroporation (IRE) ablation, the medical professional 34 can operate the handle 32 to position the distal end 73 such that one or more electrodes 40 engage the heart tissue at the desired location(s).

[0023] In the configuration shown in Figure 1, the control console 24 is connected to the surface electrodes by a cable 42, which typically comprises an adhesive skin patch 44 attached to the patient 28. The control console 24 includes a processor 46, which, together with a current tracking module 48, determines the position coordinates of the distal end 73 within the heart 26 based on the impedance and / or current measured between the adhesive skin patch 44 and the electrode 40 attached to the basket assembly 38. In addition to being used as a position sensor during medical procedures, the electrode 40 can perform other tasks, such as ablating tissue within the heart.

[0024] As described above, together with the current tracking module 48, the processor 46 can determine the position coordinates of the distal end 73 within the heart 26 based on the impedance and / or current measured between the adhesive skin patch 44 and the electrode 40. Such a determination is typically made after a calibration process has been performed to associate the impedance or current with a known position at the distal end 73. While the embodiments presented herein describe an electrode 40 configured to deliver IRE ablation energy to tissue within the heart 26, configuring the electrode 40 to deliver any other type of ablation energy to tissue in any body cavity is considered to be within the spirit and scope of the invention.

[0025] The processor 46 may comprise a real-time noise reduction circuit 50, typically configured as a field-programmable gate array (FPGA), followed by an analog-to-digital (A / D) signal conversion integrated circuit 52. The processor can be programmed to execute one or more algorithms disclosed herein, each of which includes steps described below. The processor uses circuits 50 and 52, as well as module features described in more detail below, to execute one or more algorithms.

[0026] The medical system shown in Figure 1 measures the position of the distal end 73 using impedance or current-based sensing, but other position tracking techniques (e.g., techniques using magnetic-based sensors) may be used. Impedance and current-based position tracking techniques are described, for example, in U.S. Patents 5,983,126, 6,456,864, and 5,944,022. The position detection methods described above are implemented in the CARTO® system described above and are described in detail in the patents cited above.

[0027] The control console 24 also includes an input / output (I / O) communication interface 54 that enables the control console 24 to transmit signals to and from the electrodes 40 and the adhesive skin patch 44. In the configuration shown in Figure 1, the control console 24 further comprises an electrical signal generator 56 and a switching module 58. Although the embodiments described herein show the electrical signal generator as an IRE ablation module 56 (i.e., the electrical signal generator 56 is also referred to herein as an IRE ablation module 56), other types of electrical signal generators are considered to be within the spirit and scope of the invention. For example, the electrical signal generator 56 may be configured to generate radio frequency (RF) energy.

[0028] The IRE ablation module 56 can be configured to generate IRE pulses containing peak power in the range of tens of kilowatts. As described below, the medical system 20 performs IRE ablation by having the IRE ablation module 56 simultaneously deliver IRE pulses to pairs of electrodes 40. In some embodiments, a given pair of electrodes comprises two sets of electrodes 40, each set having at least one electrode 40. Using a switching module 58, the IRE ablation module 56 can independently deliver one or more IRE pulses to each pair of electrodes.

[0029] To dissipate heat and improve the efficiency of the ablation process, the system 20 supplies irrigation fluid (e.g., ordinary saline) to the distal end 73 through a channel (not shown) in the insertion tube 74. The control console 24 includes an irrigation module 60 for monitoring and controlling irrigation parameters such as the pressure and temperature of the irrigation fluid.

[0030] Typically, based on signals received from electrodes 40 and / or adhesive skin patches 44, the processor 46 can generate an electroanatomical map 62 showing the location of the distal end 73 within the patient's body. During the procedure, the processor 46 can present the map 62 to the medical professional 34 on a display 64 and store the data representing the electroanatomical map in memory 66. Memory 66 may comprise any suitable volatile memory and / or non-volatile memory, such as random-access memory or a hard disk drive.

[0031] In some embodiments, a medical professional 34 can interact with the map 62 using one or more input devices 68. In alternative embodiments, the display 64 may include a touchscreen that can be configured to receive input from the medical professional 34 in addition to presenting the map 62.

[0032] Figure 2 is a schematic diagram of a distal end 73 equipped with an expandable basket assembly 38 according to one embodiment of the present invention. The basket assembly 38 can adopt an expandable configuration when not constrained, for example, by advancing from the insertion sheath lumen 70 of the insertion sheath 30.

[0033] In Figure 2, the electrodes 40 can be distinguished by adding letters to their identification numbers, and as a result, the electrodes comprise electrodes 40A and 40B. In the embodiments described herein, electrode 40A may be referred to as the axial electrode 40A, and electrode 40B may be referred to as the radial electrode 40B.

[0034] For example, the basket assembly 38 includes a number of elastic spines 72 formed at the distal end 73 of the insertion tube 74. The proximal end 71 of the basket assembly 38 is connected to the distal end 73 of the insertion tube 74, and the spines 72 are joined at the distal end 80 of the basket assembly (Figure 2).

[0035] During a medical procedure, a medical professional 34 can deploy the basket assembly 38 by extending an insertion tube 74 from the distal end 36 of the insertion sheath 30. The spine 72 may have an oval (e.g., elliptical or circular) or rectangular (may appear flat) cross-section and typically contains a flexible and resilient material (e.g., a shape memory alloy such as nickel-titanium, also known as nitinol). In the expanded configuration, the basket assembly 38 has an expanded arrangement in which the spine 72 is curved radially outward 75 from the longitudinal axis 77 of the basket assembly.

[0036] In the configuration shown in Figure 2, one or more electrodes 40B are inserted into each given spine 72 in order to fit the electrodes into the spines. Each spine 72 has an outer side surface 76 and an inner side surface 78. In embodiments of the present invention, for a given radial electrode 40B fitted into a given spine 72, the given spine is assumed to be planar in the given radial electrode, where the plane asymmetrically divides the given electrode, resulting in more conductive material on the outer side than on the inner side (of the plane). In the inset of Figure 2 showing a side view of electrode 40B, spine 72 extends through electrode 40B, and as a result, spine 72 is offset or "asymmetrical" with respect to the center line LL by being on one side of the center line LL. When spine 72 is offset (by being on one side of the center line LL), more of the upper surface of electrode 40B (inset of Figure 2) extends into biological tissue.

[0037] In these embodiments, each electrode 40 (i.e., when fitted to a given spine 72) includes a conductive material that, due to the asymmetry described above, is geometrically biased toward the outer surface of each spine 72. Thus, each given radial electrode 40B has a larger surface area on its outer side than on the surface area of ​​the inner side of a given electrode. By biasing the radial electrode 40B toward the outer side 76, the radial electrode delivers more ablation energy from the portion of the radial electrode on the outer side of the spine (i.e., significantly more ablation energy than that delivered from the portion of the radial electrode on the inner side of the spine).

[0038] In embodiments of the present invention, the probe 22 also comprises an axial electrode 40A positioned at the distal end 80 of the basket assembly 38. The axial electrode 40A has a circular shape and is described in Figures 3 to 5 below. The three spines 72 can be fixed to each other (e.g., welded, brazed, or bonded) at the intersection of the spines 72 at the distal end 80 of the basket 38. The electrode 40A may have an outer surface fixed (e.g., welded, brazed, or bonded) to one or more outer surfaces of the three spines that intersect at the distal end 80 of the basket 38.

[0039] In the embodiments described herein, the electrode 40 may be configured to deliver ablation energy to tissue within the heart 26. In addition to delivering ablation energy using the electrode 40, the electrode may also be used to determine the location of the basket assembly 38 and / or measure physiological properties such as local surface potential at each location on the tissue within the heart 26.

[0040] Ideal materials for forming the electrode 40 include gold, platinum, and palladium (and their respective alloys). These materials also have very high thermal conductivity, which allows the minimal heat generated on the tissue (i.e., by the ablation energy delivered to the tissue) to be conducted through the electrode to the back side of the electrode (i.e., the part of the electrode on the inner side of the spine) and then to the blood pool in the heart 26.

[0041] The probe 22 also includes a pair of wires 82 that connect the IRE ablation module 56 to the electrode 40. In some embodiments, each spine 72 includes at least one wire 82 attached to its internal side surface 78.

[0042] In some embodiments, the distal end 80 of the basket assembly 38 includes a stem 84 that extends longitudinally from the distal end 73 of the insertion tube 74. As described above, the control console 24 includes an irrigation module 60 that delivers irrigation fluid to the distal end 73. The stem 84 includes a plurality of spray ports 86, each given spray port 86 being angled to aim at delivering irrigation fluid to either a given electrode 40 or tissue within the heart 26 (i.e., by aiming at delivery between two adjacent spines 72).

[0043] Since the electrode 40 does not have a spray port for delivering the irrigation fluid, the above configuration allows heat to be transferred from the tissue (i.e., during the ablation procedure) to the portion of the electrode on the inner side of the spine, and the electrode can be cooled by directing the irrigation fluid to the portion of the electrode on the inner side of the spine via the spray port 86.

[0044] Figure 3 is a schematic lateral (i.e., top-down) view of an axial electrode 40A according to one embodiment of the present invention. In this embodiment of the present invention, the axial electrode 40A is configured to deliver ablation energy (i.e., from the IRE ablation module 56) to the tissue within the heart 26. Thus, the axial electrode 40A can have a diameter 90 (i.e., between the sides 92 of the axial electrode) of at least 1.5 millimeters (mm). Typical values ​​for the diameter 90 are 1.5, 1.75, 2.0, 2.25, 2.5 mm, and 3.0 mm. These larger diameters also provide the axial electrode 40A with sufficient lateral surface area to dissipate heat during ablation.

[0045] Figure 4 is a schematic side view of an axial electrode 40A according to one embodiment of the present invention. In some embodiments, the axial electrode 40A has a minimum thickness of 100 which is at least 20% of the diameter 90 (i.e., due to the rounded surface of the axial electrode).

[0046] In embodiments of the present invention, the axial electrode 40A has a rounded surface 102, which includes a rounded distal end 104, a proximal end 106, and a side 92. Therefore, the surface 102 has no edges. In some embodiments, the side 92 is rounded to have the largest possible radius of curvature 107 without forming an edge. Therefore, the radius of curvature 107 can be between (at least) one-quarter (25%) and (up to) one-half (50%) of the thickness 100. The minimum radius of curvature of the side 92 usually occurs at the endpoint of the diameter 90, which is schematically shown in the figure by a circle 108 having a center 109 tangent to one of the endpoints of the diameter 90.

[0047] As described above, the axial electrode 40A has a mushroom-shaped (or biscuit-shaped) form, and its rounded surface 102 and thickness constraints result in (a) the axial electrode being non-traumatic to engaging tissue within the heart 26 (or tissue in any other body cavity of the patient 28), (b) preventing high current densities that could cause arc discharge during IRE ablation, (c) providing the axial electrode with sufficient surface area to dissipate heat during ablation, and (d) improving the operability of the axial electrode.

[0048] Figure 5 is a schematic side view of a basket assembly 38 in a folded configuration, arranged generally along the longitudinal axis 77, according to one embodiment of the present invention. As shown in Figure 5, the outward bias of the electrode 40 allows the spine 72 to be coplanar with the insertion tube 74 when the basket assembly 38 is folded within the insertion sheath 30.

[0049] In some embodiments, the lumen 70 has a lumen diameter 110 of 3.0 to 3.33 mm (i.e., the medical probe 22 is a 10-French catheter). In these embodiments, the diameter 90 of the axial electrode 40A is smaller than the lumen diameter 110 so that the basket assembly 38 can traverse the lumen 70.

[0050] Figure 6 is a schematic flowchart illustrating a method for performing a tissue ablation medical procedure within a ventricle 140 of the heart 26 using a medical probe 22, and Figures 7 and 8 are schematic drawings of the distal end 73 of the ventricle of the heart during a medical procedure according to one embodiment of the present invention.

[0051] In the tissue selection step 120, the medical professional 34 selects a region 142 of intracardiac tissue 144, and in the insertion step 122, the medical professional inserts the distal end 36 of the insertion sheath 30 into the ventricle 140 of the heart 26.

[0052] In deployment step 124, the medical professional deploys the basket assembly 38 from the lumen 70 into the chamber 140.

[0053] When a medical professional 34 operates the basket assembly in the room (for example, by operating the handle 32), the processor 46 determines the position of the basket assembly in the room in the position determination step 126. In some embodiments, the processor 46 can present the position of the basket assembly 38 to the medical professional 34 (i.e., on the map 62 on the display 64).

[0054] In the ablation type selection step 128, if the medical professional 34 wishes to ablate a selected area of ​​tissue 144 using only the axial electrode 40A, in the first positioning step 130, the medical professional 34 positions the basket assembly 38 so that the axial electrode 40A compresses the selected area on the intracardiac tissue 144, as shown in Figure 7.

[0055] In the first ablation step 132, in response to input from a medical professional 34, the IRE ablation module 56 transmits an IRE pulse to an axial electrode 40A, which delivers it to a selected area of ​​intracardiac tissue 144, and the method ends. In some embodiments, the IRE ablation module 56 may receive input from a given input device 68 or from an additional input device (not shown) on the handle 32.

[0056] While embodiments of this specification describe an IRE ablation module 56 delivering IRE pulses to one or more electrodes 40 to ablate intracardiac tissue 144, configuring the medical system 20 to deliver other types of ablation energy (e.g., radio frequency energy) to any of the electrodes 40 is considered to be within the spirit and scope of the invention.

[0057] Returning to step 128, if the medical professional 34 wishes to use one or more pairs of electrodes 40 having axial electrodes 40A, in the second positioning step 134, the medical professional 34 positions the basket assembly 38 so that the axial electrodes 40A and one or more radial electrodes 40B press against a selected area on the intracardiac tissue 144, as shown in Figure 8.

[0058] In electrode selection step 136, the medical professional 34 selects an axial electrode and at least one radial electrode 40B that engage with the intracardiac tissue 144 (for example, using a given input device 68), and in second ablation step 138, in response to input from the medical professional 34, the IRE ablation module 56 transmits an IRE pulse to the selected electrode, which delivers it to a selected area of ​​the intracardiac tissue 144, and the method is completed.

[0059] In one embodiment, the selected electrode comprises a pair of electrodes 40. In these embodiments, the medical system 20 performs IRE ablation by delivering IRE pulses to the pair of electrodes 40. In additional embodiments, a given pair of electrodes comprises two sets of electrodes 40, each set having at least one electrode 40. The electrodes in any given pair can be fixed to a single spine 72 or multiple spines 72. Using a switching module 58, the IRE ablation module 56 can independently deliver one or more IRE pulses to each pair of electrodes.

[0060] The embodiments described above are cited as examples, and it will be understood that the present invention is not limited to those specifically shown and described above. Rather, the scope of the present invention includes both combinations and partial combinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art, which will be conceivable to those skilled in the art by reading the foregoing description.

[0061] [Implementation Method] (1) A medical probe, An insertion tube configured to be inserted into a patient's body cavity, A basket assembly having a proximal end distally connected to the insertion tube and comprising a plurality of elastic spines, wherein the elastic spines are configured to curve radially outward from the axis of the basket assembly and are joined at the distal end of the basket assembly, An axial electrode is positioned at the distal end of the basket assembly, has a diameter of at least 1.5 millimeters, and is configured to contact the tissue within the body cavity, A medical probe comprising a plurality of radial electrodes, each configured to contact the tissue within the body cavity and having a radial electrode positioned on the spine. (2) The medical probe according to Embodiment 1, further comprising an electrical signal generator connected to the axial electrode and the radial electrode. (3) The medical probe according to Embodiment 2, wherein the electrical signal generator is configured to deliver irreversible electroporation (IRE) pulses to the axial electrode. (4) The medical probe according to Embodiment 2, wherein the electrical signal generator is configured to simultaneously deliver IRE energy to the axial electrode and at least one radial electrode. (5) The medical probe according to Embodiment 2, wherein the electrical signal generator is configured to deliver radio frequency energy to the axial electrode.

[0062] (6) The medical probe according to Embodiment 1, wherein the spine has an external side and an internal side, and each given radial electrode comprises a conductive material biased toward the external side of the respective spine. (7) The medical probe according to Embodiment 1, wherein the axial electrode has a circular shape with a rounded surface. (8) The medical probe according to Embodiment 7, wherein the axial electrode has a thickness of at least 20% of the diameter. (9) The medical probe according to Embodiment 8, wherein the axial electrode has a side having a radius of curvature that is at least 25% of the thickness. (10) The medical probe according to Embodiment 8, wherein the axial electrode has a side surface having a radius of curvature of up to 50% of the thickness.

[0063] (11) A method for manufacturing a medical probe, To provide an insertion tube configured to be inserted into a patient's body cavity, To provide a basket assembly having a proximal end distally connected to the insertion tube and comprising a plurality of elastic spines, wherein the elastic spines are configured to curve radially outward from the axis of the basket assembly and are coupled at the distal end of the basket assembly. To provide an axial electrode positioned at the distal end of the basket assembly, having a diameter of at least 1.5 millimeters, and configured to contact the tissue within the body cavity, A method comprising providing a plurality of radial electrodes, each comprising radial electrodes configured to contact the tissue within the body cavity and positioned on the spine. (12) The method according to embodiment 11, further comprising providing an electrical signal generator connected to the axial electrode and the radial electrode. (13) The method according to embodiment 12, wherein the electrical signal generator is configured to deliver irreversible electroporation (IRE) pulses to the axial electrode. (14) The method according to embodiment 12, wherein the electrical signal generator is configured to simultaneously deliver IRE energy to the axial electrode and at least one radial electrode. (15) The method according to embodiment 12, wherein the electrical signal generator is configured to deliver radio frequency energy to the axial electrode.

[0064] (16) The method according to Embodiment 11, wherein the spines each have an outer surface and an inner surface, and each given radial electrode comprises a conductive material biased toward the outer surface of each spine. (17) The method according to embodiment 11, wherein the axial electrode has a circular shape with a rounded surface. (18) The method according to embodiment 17, wherein the axial electrode has a thickness of at least 20% of the diameter. (19) The method according to embodiment 18, wherein the axial electrode has a side surface having a radius of curvature that is at least 25% of the thickness. (20) The method according to embodiment 18, wherein the axial electrode has a side surface having a radius of curvature that is up to 50% of the thickness.

[0065] (21) A treatment method, Inserting the insertion tube, which has a distal end containing a lumen through which the insertion tube penetrates, into a body cavity, A basket assembly having a proximal end distally connected to the insertion tube and comprising a plurality of elastic spines is deployed into the body cavity from the distal end, wherein the elastic spines are configured to curve radially outward from the axis of the basket assembly and are coupled at the distal end of the basket assembly, and the basket assembly is An axial electrode is positioned at the distal end of the basket assembly, has a diameter of at least 1.5 millimeters, and is configured to contact the tissue within the body cavity, A plurality of radial electrodes, each configured to contact the tissue within the body cavity and positioned on the spine, are provided for deployment. Positioning the basket assembly such that the axial electrode compresses the tissue within the body cavity, A treatment method comprising transmitting ablation energy to the tissue via the axial electrode.

Claims

1. A medical probe, An insertion tube configured to be inserted into a patient's body cavity, A basket assembly having a proximal end distally connected to the insertion tube and comprising a plurality of elastic spines, wherein the plurality of elastic spines are configured to curve radially outward from the axis of the basket assembly and are joined at the distal end of the basket assembly, An axial electrode, attached to the plurality of elastic spines and positioned at the distal end of the basket assembly, The axial electrode has a diameter of at least 1.5 millimeters and a thickness of at least 20% of the diameter. The axial electrode has a circular shape with a rounded surface. The axial electrode is configured to be in contact with the tissue within the body cavity. The axial electrode has a side surface having a radius of curvature that is at least 25% of the thickness and at most 50% of the thickness, A medical probe comprising a plurality of radial electrodes, each configured to contact the tissue within the body cavity and having radial electrodes arranged on a plurality of elastic spines.

2. The medical probe according to claim 1, further comprising an electrical signal generator connected to the axial electrode and the radial electrode.

3. The medical probe according to claim 2, wherein the electrical signal generator is configured to deliver irreversible electroporation (IRE) pulses to the axial electrode.

4. The medical probe according to claim 2, wherein the electrical signal generator is configured to simultaneously deliver IRE energy to at least one of the axial electrode and the radial electrode.

5. The medical probe according to claim 2, wherein the electrical signal generator is configured to deliver radio frequency energy to the axial electrode.

6. The medical probe according to claim 1, wherein the plurality of elastic spines each have an external side and an internal side, and each given radial electrode comprises a conductive material biased toward the external side of each elastic spine.

7. The medical probe according to claim 1, wherein the circular shape comprises a distal end, a proximal end, and a side surface that are all rounded.

8. The medical probe according to claim 1, further comprising a stem extending longitudinally from the distal end of the insertion tube, wherein the distal end of the stem is located within the internal space of the basket assembly and spaced apart from the axial electrode.

9. The medical probe according to claim 8, wherein the stem comprises a plurality of spray ports for delivering an irrigation fluid to at least one of the axial electrode, the radial electrode, and the tissue within the body cavity.

10. The medical probe according to claim 1, wherein the plurality of elastic spines each have an external side surface and an internal side surface, and each given radial electrode includes a conductive material extending radially outward from the external side surface of each elastic spine.

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