Basket catheter with insulated ablation electrodes

Abstract

The invention is entitled "Basket Catheter with Insulated Ablation Electrodes." A catheter is disclosed that includes a shaft for insertion into an organ of a patient and an expandable distal end assembly coupled to the shaft and an apex of the catheter and including a plurality of struts. In at least a given strut of the plurality of struts, at least sixty percent of a length of the given strut is uninsulated and configured to make contact with tissue of the organ and apply radio frequency (RF) pulses to the tissue.

Description

[0001] Cross-reference to related applications

[0002] This application relates to U.S. Patent Application No. BIO6389USNP1 / 1002-2268, filed on the same date and entitled “Basket Catheter having insulated ablation electrodes and diagnostic electrodes,” the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates generally to medical catheters, and more particularly to ablation catheters having an expandable distal end. Background Technology

[0004] Basket catheters can be used in a variety of medical applications, such as cardiology. Several types of basket catheters with multiple strips are designed to enable the detection and treatment of arrhythmias.

[0005] For example, U.S. Patent Application Publication 2014 / 0238175 describes methods, systems, and devices for delivering treatment to a target site. The system may include a guiding component, an expandable support device coupled to a distal end of the guiding component, and an actuating member disposed on the expandable support device. The expandable support device may be configured to switch between a collapsed configuration and an expanded configuration.

[0006] U.S. Patent 6,292,695 describes a method for controlling cardiac fibrillation, tachycardia, or arrhythmia using an electrophysiological catheter having a distal segment housing at least one stimulating electrode stably positioned at a selected intravascular location. The electrode is connected to a stimulation device, and stimulation is applied transvascularly across the vessel wall to the sympathetic or parasympathetic nerves innervating the heart with an intensity sufficient to depolarize nerves and achieve cardiac control.

[0007] U.S. Patent 6,421,556 describes systems and methods for diagnosing and treating tissues, wherein the systems and methods transmit electrical energy pulses that temporarily immobilize a region of tissue, thereby temporarily rendering it without an electrical response. The systems and methods sense the electrophysiological effects induced by the transmitted pulses. The systems and methods alter the electrophysiological properties of the tissue in or near the region based at least in part on the sensed electrophysiological effects. The alteration of electrophysiological properties can be achieved, for example, by tissue ablation or by the application of a drug. In one specific embodiment, radiofrequency energy is used to temporarily immobilize the tissue and ablate the tissue via a common electrode.

[0008] U.S. Patent Application Publication 2015 / 0182282 describes various systems and techniques for generating plasma and / or electric fields, alone or in combination with other therapies, and applying plasma and / or electric fields to living tissue to treat various tissue conditions and other conditions (such as tumors, bacterial infections, etc.), while limiting the generation of current within said tissue.

[0009] U.S. Patent Application Publication No. 2006 / 0100669 illustrates and describes a system for atrial fibrillation using a basket catheter. Summary of the Invention

[0010] Embodiments of the present invention described herein provide a catheter comprising an axis for insertion into a patient's organ and an expandable distal end assembly coupled to the axis and the apex of the catheter, and comprising a plurality of strips. At least one of these strips has at least 60% (60)% of its length being non-insulated and configured to contact tissue of the organ and apply radio frequency (RF) pulses to the tissue.

[0011] In some embodiments, up to forty (40) percent of the length of the given strip is insulated and positioned between the non-insulated length and the apex. In other embodiments, the insulated length is coated with an electrically insulating layer. In still other embodiments, at least the given strip comprises a nickel-titanium alloy.

[0012] In one embodiment, the vertex has a flat surface orthogonal to the axis of the shaft. In another embodiment, the flat surface is insulated. In yet another embodiment, the conduit includes a bump stop coupled to the vertex and configured to limit a minimum distance between the shaft and the vertex.

[0013] According to an embodiment of the invention, a method for manufacturing a catheter is also provided, the method comprising receiving a plurality of strips such that at least sixty (60)% of the length of at least one given strip of the plurality of strips is non-insulated and configured to contact tissue of a patient’s organ and to apply a radio frequency (RF) pulse to the tissue. The plurality of strips are assembled together for manufacturing an expandable distal end assembly, and the expandable distal end assembly is coupled to a shaft and the apex of the catheter.

[0014] The invention will be more fully understood through the following detailed description of embodiments thereof, taken in conjunction with the accompanying drawings, wherein: Attached Figure Description

[0015] Figure 1 A schematic diagram of a catheter-based localization-tracking and ablation system according to an embodiment of the present invention;

[0016] Figure 2 and Figure 3 A schematic illustration of the distal end assembly in the expanded position according to an embodiment of the present invention;

[0017] Figure 4 A flowchart illustrating a method for manufacturing a basket-shaped catheter with an insulated ablation electrode according to an embodiment of the present invention is shown schematically; and

[0018] Figure 5 For illustrative purposes, an embodiment of the invention is shown for use. Figure 3 The flowchart shows a method for ablating tissue using a distal end component. Detailed Implementation

[0019] Overview

[0020] The embodiments of the invention described below provide various configurations of improved distal end assemblies for use in catheters of ablation systems. In some embodiments, the catheter includes a shaft for inserting the distal end assembly into the patient's heart, and an expandable distal end assembly (such as a basket-shaped piece) coupled to the shaft and the apex of the catheter.

[0021] In some embodiments, the distal end assembly includes a plurality of strips, at least one of which is typically made entirely of solid nitinol and has at least two segments. The first segment of the strip is non-insulated, conductive, and has at least 60% of the length of the strip. The first segment is configured to contact tissue of the heart and to apply radio frequency (RF) pulses to the tissue.

[0022] In some embodiments, a second section of the strip is insulated, comprising up to 40% of the strip's length, and positioned between the non-insulated section and the apex of the conduit. The insulated section may comprise nitinol of the strip coated with an electrically insulating layer.

[0023] In some embodiments, the apex is electrically insulated from the strip and has a flat surface orthogonal to the axis of the shaft (e.g., the longitudinal axis). It should be noted that in the above configuration, the first segment is conductive and configured to ablate cardiac tissue, while the second segment and the apex are electrically insulated and configured to be electrically insulated between the non-insulated segments of the strip. In such embodiments, in an ablation catheter having a first strip and a second strip (each having a first segment and a second segment), the processor of the ablation system is configured to control a radio frequency (RF) pulse generator to apply one or more RF pulses to the first strip, without applying any RF pulses to the second strip.

[0024] Typically, intracardiac signal mapping is performed before performing an ablation procedure, for example, to define the target tissue for ablation. In some implementations, a long, non-insulated segment can be used to sense intracardiac signals. However, at least 60% of the non-insulated segment, including the long strip, may come into contact with long segments of cardiac tissue, and therefore may not be able to sense intracardiac signals with a sufficiently high lateral resolution (e.g., about 1.0 mm) for tissue mapping prior to ablation.

[0025] In some embodiments, the aforementioned basket-shaped distal end assembly may include one or more diagnostic electrodes, also referred to herein as sensing electrodes. In this example, the sensing electrodes are coupled to an electrically insulated section and / or a vertex.

[0026] In some implementations, one or more of the sensing electrodes are configured, for example, to sense a unipolar signal between the sensing electrode and a reference electrode attached to the skin or any other tissue of the patient.

[0027] In other embodiments, two or more of the sensing electrodes are disposed on the vertex and the insulating section and are configured to sense bipolar signals. For example, a first sensing electrode and a second sensing electrode may be disposed on the insulating section of a first strip, a third sensing electrode may be disposed on the insulating section of a second strip, and a fourth sensing electrode may be disposed on the vertex. In this configuration, the processor of the ablation system is configured to receive multiple bipolar signals from any pair of the four sensing electrodes. For example, (i) a first bipolar signal between the first and second electrodes, (ii) a second bipolar signal between the second and third electrodes, and (iii) a third bipolar signal between the third and fourth sensing electrodes.

[0028] The disclosed technique is particularly effective for ablation of (i) long and narrow tissues, such as when one or more RF pulses are applied to a single strip, or (ii) long and wide tissues, such as when RF pulses are applied to multiple strips. Therefore, the disclosed technique can reduce the total cycle time of an ablation procedure.

[0029] Furthermore, the disclosed technology reduces the need to attach a dedicated ablation electrode to the expandable catheter, thereby improving the mechanical flexibility of the strip and reducing the costs associated with manufacturing the expandable distal end assembly of the ablation catheter.

[0030] System Description

[0031] Figure 1This is a schematic illustration of a catheter-based localization-tracking and ablation system 20 according to an embodiment of the present invention. In some embodiments, system 20 includes a catheter 22 (an expandable cardiac catheter in this example) and a control console 24. In the embodiments described herein, catheter 22 can be used for any suitable therapeutic and / or diagnostic purpose, such as ablation of tissue in the heart 26, and for mapping arrhythmias by sensing intracardiac electrical signals.

[0032] In some embodiments, console 24 includes processor 42 (typically a general-purpose computer) with suitable front-end and interface circuitry for receiving signals from conduit 22 and for controlling other components of system 20 as described herein. Processor 42 can be programmed in software to perform functions used by the system and is configured to store data for the software in memory 50. For example, the software can be downloaded electronically to console 24 via a network, or it can be provided on a non-transitory tangible medium such as an optical, magnetic, or electronic memory medium. Alternatively, some or all of the functions of processor 42 can be performed using application-specific integrated circuits (ASICs) or any suitable type of programmable digital hardware components.

[0033] Now refer to illustration 25. In some embodiments, the catheter 22 includes multiple strips (hereinafter referred to as...) Figure 2 and Figure 3 The distal end assembly 40 (shown in detail) and the shaft 23 for inserting the distal end assembly 40 into a target location for ablation of tissue in the heart 26. During the ablation procedure, the physician 30 inserts a catheter 22 through the vascular system of the patient 28 lying on the operating table 29. The physician 30 uses a manipulator 32 located near the proximal end of the catheter 22 to move the distal end assembly 40 to the target location in the heart 26; this manipulator is connected to the interface circuitry of the processor 42.

[0034] In some embodiments, catheter 22 includes a position sensor 39 of a position tracking system coupled to the distal end of catheter 22, such as immediately adjacent to distal end assembly 40. In this example, position sensor 39 includes a magnetic position sensor, but in other embodiments, any other suitable type of position sensor (e.g., other than magnetic) may be used.

[0035] Now see back Figure 1A general view. In some embodiments, during navigation of the distal end assembly 40 within the heart 26, the processor 42 receives signals from the magnetic position sensor 39 in response to a magnetic field from an external field generator 36, for example, to measure the position of the distal end assembly 40 within the heart 26. In some embodiments, the console 24 includes drive circuitry 34 configured to drive the magnetic field generator 36. The magnetic field generator 36 is placed at a known location outside the patient 28, for example, below the workbench 29.

[0036] In some implementations, the processor 42 is configured to, for example, display the tracking position of the distal end component 40 on an image 44 superimposed on the heart 26 on a display 46 of the console 24.

[0037] Position sensing methods using external magnetic fields have been implemented in various medical applications, such as in CARTO, manufactured by Biosense Webster Inc. (Irvine, California). TM The system is implemented and described in detail in U.S. Patents 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, PCT Patent Publication WO 96 / 05768, and U.S. Patent Application Publications 2002 / 0065455 A1, 2003 / 0120150 A1 and 2004 / 0068178 A1, the disclosures of which are incorporated herein by reference in their entirety.

[0038] Distal end assembly with insulated ablation electrode

[0039] Figure 2 This is a schematic diagram of the distal end assembly 40 in the expanded position according to an embodiment of the present invention.

[0040] In some embodiments, the distal end assembly 40 comprises a plurality of strips 55 made of a solid nickel-titanium alloy (such as solid nitinol) or any other suitable alloy or material. It should be noted that nitinol is chosen for the strips 55 because it is conductive and sufficiently flexible to conform to the tissue intended to be ablated. Therefore, any other material chosen for the strips 55 must be conductive and sufficiently flexible to conform to the aforementioned tissue.

[0041] In some embodiments, at least one given strip 55 of the distal end assembly 40 and typically each strip 55 has a conductive segment, referred to herein as segment 66, which is configured to serve as an ablation electrode for ablation of tissue at a target location in the heart 26.

[0042] In some embodiments, segment 66 comprises at least sixty (60) percent of the length of strip 55. Segment 66 is non-insulated (e.g., conductive as described above) and is configured to contact the tissue of heart 26 and to apply radio frequency (RF) pulses to the heart tissue during the ablation procedure.

[0043] In other embodiments, segment 66 may include any other suitable portion of the length of strip 55.

[0044] In some embodiments, each of the aforementioned given strips 55 and typically the distal end assembly 40 has a segment 77 that is at most forty (40)% of the length of the corresponding (e.g., given) strip 55. The segment 77 is insulated and is located between the segment 66 and the apex 88 of the conduit 22.

[0045] In some embodiments, segment 77 is configured to be electrically insulated from segments 66 of strip 55, at least at vertex 88, which is generally electrically insulated from the strip. In other embodiments, vertex 88 may comprise a conductive material and may be used as an additional ablation electrode for the distal end assembly 40.

[0046] In some implementations, vertex 88 has a flat surface 89 that is typically (but not necessarily) orthogonal to the axis of axis 23.

[0047] It should be noted that segment 66 has a typical length between approximately 10 mm and 40 mm. Therefore, when multiple strips 55 are applying pulses with predefined energy and duration, the distal end assembly 40 is configured to ablate approximately 256 mm of tissue at the target location of the heart 26. 2 The area.

[0048] In the context of this disclosure and claims, the terms “about” or “approximately” for any numerical value or range indicate a suitable dimensional tolerance that allows a portion or assembly of parts to function for the intended purpose described herein. More specifically, “about” or “approximately” may refer to a range of ±20% of the enumerated values, for example, “about 90%” may refer to a range of 71% to 99% of the values.

[0049] In some embodiments, the distal end assembly 40 includes a coupling element (a ring 54 in this example) coupled to the proximal end of the strip 55 and configured to be threaded onto the shaft 23 for coupling between the shaft 23 and the distal end assembly 40. Note that each strip 55 is electrically connected to the catheter 22, for example, via a wire (not shown) extending from the proximal end of each strip 55. Thus, the processor 42 can control the electrical connection between the console 24 and each segment 66 of the strip 55. This controlled and selective connection is important for applying RF pulses to the tissue of the heart 26 via selected strips 55, and similarly, from selected electrodes positioned to contact the tissue of the heart 26 (e.g., hereinafter). Figure 3 The segment 66 (or other electrodes) described herein receives intracardiac electrical signals.

[0050] In some implementations, when the physician 30 moves the distal end of the catheter 22 to a target location in the heart 26, the distal end assembly 40 is in a collapsed position, in which all the strips 55 are straightened. When the distal end assembly 40 is positioned at the target location in the heart 26, the physician 30 typically reduces the distance between the ring 54 and the apex 88 (e.g., by pulling the apex 88 toward the ring 54, or by pushing the ring 54 toward the apex 88, or using any other technique) to place the distal end assembly 40 in an expanded position in which the strips 55 are bent, such as... Figure 2 As shown in the image.

[0051] In some embodiments, the distal end assembly 40 includes a bump stop 91 coupled to the vertex 88 and configured to control the minimum distance between the shaft 23 and the vertex 88. That is, the bump stop 91 is fixed to a proximal position to the vertex 88 such that the bump stop 91 faces the end of the shaft 23. Figure 2 At the expanded position shown in the example, the distal end assembly 40 may have a gap distance 92 (measured along the longitudinal axis 70) between the end of shaft 23 and the bump stop 91. The gap distance 92 may be any value from about 1 mm to 13 mm, depending on the total diameter of the catheter. In a preferred embodiment, the gap distance 92 is about 3 mm, as measured along the longitudinal axis 70. In such embodiments, when the physician 30 further reduces the distance between ring 54 and apex 88, the bump stop 91 is configured to contact the end of shaft 23 such that the gap distance 92 is nonexistent (i.e., equal to zero), and thereby limits the minimum distance between shaft 23 and apex 88. In other words, the bump stop 91 acts as a hard stop configured to prevent the basket-shaped distal end assembly 40 from becoming completely flat, and thereby causing the nitinol base to buckle.

[0052] In some embodiments, the physician 30 may use the manipulator 32 to control the distance between the apex 88 and the ring 54, and thus control the amount of expansion of the distal end assembly 40. It should be noted that when an RF pulse is applied to the distal end assembly 40, segment 66 acts as an ablation electrode and applies the RF pulse to the tissue it contacts, while segment 77 is insulated and therefore does not apply an RF pulse to the tissue. Furthermore, segment 77 is electrically isolated between segments 66 of the distal end assembly 40. In this configuration, the processor 42 may control an RF pulse generator to apply one or more RF pulses to the first segment 66 of the first strip 55, and not apply any RF pulses to the second segment 66 of the second strip 55.

[0053] Diagnostic electrodes coupled to the apex of the distal end assembly

[0054] Figure 3 This is a schematic illustration of the distal end assembly 80 in an expanded position according to another embodiment of the invention. The distal end assembly 80 may be replaced, for example... Figure 1 The distal end assembly 40.

[0055] In some embodiments, the distal end assembly 80 includes a plurality of strips 56, such as strips 56A, 56D, 56E and 56F, which are similar to those described above. Figure 2 Each strip 55 has an insulating section 77A, 77D, 77E, and 77F. Each strip 56 of the distal end assembly 80 includes a non-insulating section 66 having the aforementioned insulating sections. Figure 2 The dimensions, mechanical properties, and electrical properties described herein.

[0056] In some embodiments, the distal end assembly 80 includes one or more diagnostic electrodes, referred to herein as electrodes 99. In this example, electrodes 99 include (i) electrodes 99A and 99B coupled to segment 77A, (ii) electrodes 99C coupled to surface 89 of vertex 88, (iii) electrodes 99D coupled to segment 77D, (iv) electrodes 99E coupled to segment 77E, and (v) electrodes 99F coupled to segment 77F. In other embodiments, the distal end assembly 80 may include an additional suitable number of electrodes 99 disposed on any segment 77 and / or vertex 88 using any suitable configuration.

[0057] In some embodiments, when placed in contact with tissue of the heart 26, electrode 99 is configured to sense electrical signals in the tissue. In the context of this disclosure and the claims, the terms “sensing,” “mapping,” and “diagnosing” are used interchangeably, wherein a sensing electrode (e.g., electrode 99) configured to sense intracardiac signals generates signals for mapping and diagnosing the tissue of consideration of the heart 26. In such embodiments, processor 42 is configured to generate an electrophysiological mapping of the tissue of consideration of the heart 26 based on intracardiac signals received from electrode 99.

[0058] In some implementations, electrodes 99A and 99B are attached to segment 77A of strip 56A and configured to sense a bipolar signal therebetween.

[0059] In some embodiments, a bipolar signal can be sensed between electrodes 99E and 99F, which are respectively coupled to segments 77E and 77F of strips 56E and 56F. Alternatively, a bipolar signal can be sensed between electrode 99C coupled to surface 89 and electrode 99D coupled to segment 77D of strip 56D. In other words, a bipolar signal can be sensed between: (i) a pair of electrodes disposed on a single strip, and / or (ii) a pair of electrodes disposed on two different strips, and / or (iii) an electrode coupled to vertex 88 and an electrode coupled to a strip, and / or (iv) a pair of electrodes (not shown) coupled to vertex 88 at a predetermined distance from each other, such as on segment 77A of strip 56a.

[0060] In other embodiments, at least one of the electrodes 99 is configured to sense a monopolar signal, for example, relative to a reference electrode (not shown), which is positioned to contact or be attached to the skin (not shown) of the patient 28.

[0061] In some implementations, electrode 99 is coupled to the corresponding segment 77 using any suitable technique (such as crimping).

[0062] In some embodiments, the distal end assembly 80 may include wires and / or traces (not shown) configured to electrically connect each electrode 99 and the processor 42. The wires may be grouped into a braid extending between the console 24 and the shaft 23, and at the distal end of the shaft 23, each wire is routed to a corresponding electrode 99.

[0063] In some embodiments, when the distal end assembly 80 is positioned to contact the tissue of the heart 26, one or more of the electrodes 99 are configured to generate a potential gradient signal in response to a sensed potential in the tissue of the heart 26. A position sensor 39 is configured to generate a position signal in response to a sensed external magnetic field, and the position sensor is fixed at the distal end of the catheter 22 at a known distance from each electrode 99.

[0064] In some implementations, based on (i) a position signal received from position sensor 39 and (ii) a signal received from one or more electrodes 99, processor 42 is configured to, for example, display on display 46 an electrophysiological mapping of the potential sensed by the electrodes 99 at the corresponding locations in the tissue of heart 26.

[0065] In some implementations, based on electrophysiological mapping of the tissue of the heart 26, the physician 30 can position a selected strip 56 to contact the tissue to be ablated within the heart 26. Subsequently, the physician 30 and / or the processor 42 can control the system 20 to apply RF pulses to ablate the tissue of the heart 26.

[0066] This particular configuration of system 20 and the distal end assemblies 40 and 80 are illustrated by way of example to illustrate certain problems addressed by embodiments of the invention and to demonstrate the application of these embodiments in enhancing the performance of such ablation systems. However, embodiments of the invention are by no means limited to this specific type of exemplary system, and the principles described herein can be similarly applied to other types of medical systems, such as, but not limited to, electrosurgical systems and irreversible electroporation (IRE) ablation systems.

[0067] Manufacturing basket-shaped distal end assembly

[0068] Figure 4 This is a flowchart schematically illustrating a method for manufacturing distal end assemblies 40 and 80 according to an embodiment of the invention. The method begins at strip receiving step 100, wherein a plurality of strips 55 made of nitinol or any suitable nickel-titanium alloy, or any other alloy suitable for use as ablation electrodes, are received, as described above. Figure 2 and Figure 3 As described in [the text].

[0069] At coating step 102, at least one, and typically all, segments 77 of strip 55 are coated with an electrical insulating layer. At distal end assembly manufacturing step 104, distal end assemblies 40 and 80 are manufactured by (i) coupling the proximal ends of all strips 55 to ring 54, and (ii) coupling the segments 77 located at the distal ends of all strips 55 to conduit apex 88.

[0070] In other embodiments, at the strip receiving step 100, one or more of the strips 55 may have been coated with the aforementioned electrical insulating layer, making step 102 redundant and thus excluded from the method.

[0071] At electrode coupling step 106, which is performed only in the fabrication of the distal end assembly 80, one or more electrodes 99 are coupled to the vertex 88 and / or to one or more segments 77 of the strip 55, and connected to wires for conducting signals between one or more (typically all) electrodes 99 and the processor 42, as described above. Figure 3 As described above. Note that step 106 is not performed during the manufacture of the distal end assembly 40.

[0072] At the distal end assembly coupling step 108, which concludes the method, distal end assembly 40 or distal end assembly 80 is coupled to shaft 23 along axis 70, as described above. Figure 2 and Figure 3 As described above. It should be noted that in the manufacturing of the distal end assembly 40, after performing step 104, the method proceeds directly to step 108 without performing step 106, which is performed only in the manufacturing of the distal end assembly 80.

[0073] In summary, steps 100, 102, 104 and 108 are for manufacturing the distal end assembly 40, and all steps 100, 102, 104, 106 and 108 are for manufacturing the distal end assembly 80.

[0074] Provided by example Figure 4 This particular method for manufacturing distal end assemblies 40 and 80 is provided to illustrate certain problems addressed by embodiments of the invention and to demonstrate the application of these embodiments in manufacturing distal end assemblies 40 and 80 to enhance the performance of system 20. However, embodiments of the invention are by no means limited to this particular type of exemplary manufacturing process, and the principles described herein can be similarly applied to other types of distal end assemblies used in system 20 or other types of medical systems, such as, but not limited to, electrosurgical systems and irreversible electroporation (IRE) ablation systems.

[0075] Ablation procedures were performed using a basket-shaped distal end assembly.

[0076] Figure 5 This is a flowchart schematically illustrating a method for ablating tissue using a distal end assembly 80 according to an embodiment of the present invention. The method begins at catheter insertion step 200, wherein the following will be... Figure 3The distal end assembly 80, described in detail above, is inserted into the heart 26. Essentially, one or more strips 56 of the distal end assembly 80 have: (i) segments 66 configured for ablation of tissue of the heart 26, and (ii) one or more electrodes configured for sensing intracardiac electrical signals within the tissue of the heart 26, such as those described above. Figure 3 Electrodes 99A-99F are shown.

[0077] At sensing step 202, after the distal end assembly 80 is positioned adjacent to the target location within the heart 26, the physician 30 controls the expansion of the distal end assembly 80 to an expanded position. Expansion can be achieved, for example, by reducing the distance between the ring 54 and the apex 88. It should be noted that the minimum distance between the ring 54 and the apex 88 is limited by the bump stop 91, as described above. Figure 1 As described in the text. In some embodiments, at sensing step 202, at least one of vertex 88 and segment 77 (e.g., segments 77A, 77D, 77E, and 77F), and typically both, are coupled to tissue for sensing intracardiac electrical signals.

[0078] At ablation step 204, based on the signals sensed in step 202, physician 30 manipulates the distal end assembly 80 and couples segments 66 of one or more strips 56 (e.g., strips 56A, 56D, 56E, and 56F) to the tissue for performing RF ablation. Note that in step 202, the distal end assembly 80 is positioned such that axis 70 is substantially orthogonal to the tissue to position the surface 89 of vertex 88 in contact with the tissue for sensing. Furthermore, in step 204, the distal end assembly 80 is positioned such that axis 70 is substantially parallel to the tissue, such that one or more segments 66 are positioned in contact with the tissue and thereby ablate the tissue.

[0079] At the catheter retrieval step 206, which terminates the method, after the ablation is completed, the physician 30 controls the catheter 22 to cause the distal end assembly 80 to collapse (e.g., by increasing the distance between the ring 54 and the apex 88), and then removes the catheter 22 from the body of the patient 28.

[0080] In other embodiments, processor 42 may maintain electrophysiological mapping of the tissue before or at least before step 202 of the ablation procedure. In such embodiments, ablation step 204 is performed based on mapping following catheter insertion step 200, and sensing step 202 may be performed after step 204 to check whether an additional RF pulse is required to terminate the ablation procedure after step 204. If an additional RF pulse is required, the method loops back to ablation step 204, followed by sensing step 202, which continues one or more iterations until the ablation is terminated.

[0081] In an alternative embodiment, the sensing step 202 may be performed before and after the ablation step 204 in order to sense intracardiac electrical signals used to control the ablation process as described above.

[0082] While the implementation described herein primarily relates to basket catheters, the techniques described herein can also be used with any other suitable medical probe having a strip for applying energy to tissue.

[0083] It should be understood that the above embodiments are cited by way of example, and the invention is not limited to what has been specifically shown and described above. Rather, the scope of the invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which will occur to those skilled in the art upon reading the above description and which are not disclosed in the prior art. Documents incorporated herein by reference are considered an integral part of this application, except that if any terminology defined in such incorporated documents conflicts with the definitions expressly or implicitly given in this specification, only the definitions in this specification shall be considered.

Claims

1. A catheter, comprising: A shaft for insertion into a patient's organ, the shaft extending along a longitudinal axis; as well as An expandable distal end assembly coupled to the apex of the shaft and the conduit, and comprising a plurality of strips, wherein at least 60% of the length of at least one of the plurality of strips is non-insulated and configured to contact the tissue of the organ and apply a radio frequency (RF) pulse to the tissue; as well as A bump stop is coupled to the vertex and configured to limit a non-zero minimum distance between the shaft and the vertex along the longitudinal axis. The bump stop is separated from the end of the shaft, wherein there is an axial clearance between the end and the bump stop. The bump stop is configured to contact the end of the shaft to maintain the non-zero minimum distance when the axial clearance is zero.

2. The conduit of claim 1, wherein up to 40% of the length of the given strip is insulated and positioned between the non-insulated length and the apex.

3. The conduit according to claim 2, wherein the insulating length is coated with an electrically insulating layer.

4. The conduit of claim 1, wherein at least the given strip comprises a nickel-titanium alloy.

5. The conduit according to claim 1, wherein the apex has a flat surface orthogonal to the axis of the shaft.

6. The conduit of claim 5, wherein the flat surface is insulated.

7. A method for manufacturing a catheter, the method comprising: Receive a plurality of strips, wherein at least 60% of the length of at least one of the plurality of strips is non-insulated and configured to contact tissue of a patient’s organ and apply a radio frequency (RF) pulse to the tissue; The plurality of strips are assembled together for use in manufacturing an expandable distal end assembly; as well as The expandable distal end assembly is coupled to the apex of the shaft and the conduit, wherein a bump stop is disposed between the shaft and the apex to ensure a clearance between the shaft and the apex. Coupling the expandable distal end assembly includes coupling the bump stop to the apex, the bump stop being used to limit a non-zero minimum distance between the shaft and the apex. The bump stop is separated from the end of the shaft, wherein there is an axial clearance between the end and the bump stop, such that the bump stop is configured to contact the end of the shaft to maintain the non-zero minimum distance when the axial clearance is zero.

8. The method of claim 7, wherein up to 40% of the length of the given strip is insulated, and wherein coupling the expandable distal end assembly comprises coupling the insulated length to the apex.

9. The method of claim 8, further comprising coating the insulation length with an electrical insulating layer.

10. The method of claim 7, wherein at least the given strip comprises a nickel-titanium alloy.

11. The method of claim 8, wherein coupling the expandable distal end assembly to the vertex comprises coupling an insulating section of the strip to a flat surface of the vertex, the flat surface being orthogonal to the axis of the shaft.

12. The method of claim 11, wherein the flat surface is insulating.

Images