Mapping grid with high-density electrode array

Abstract

The invention is entitled "Mapping Grid with High-Density Electrode Array." The invention describes a catheter having an end effector with densely packed electrodes on three rings that are arranged in various flat configurations when the end effector is unconstrained. The end effector has first, second, and third ring members, each ring member including two ridges and a connector connecting the two ridges to define a ring extending away from a tubular member of the catheter, such that each connector of each of the first, second, and third ring members contacts only one connector of an adjacent ring member.

Description

[0001] priority

[0002] This patent application claims the benefit under the Paris Convention and 35 U.S.C. §§119 and 120 of previously filed U.S. Provisional Patent Application SN 62 / 841,154, entitled “Mapping Grid with High Density,” filed on April 30, 2019 (Attorney Docket No. BIO6150USPSP1), which is hereby incorporated by reference as if fully set forth herein. Background Art

[0003] Arrhythmias such as atrial fibrillation occur when a region of cardiac tissue abnormally conducts electrical signals to adjacent tissue, disrupting the normal cardiac cycle and causing an irregular heartbeat. A significant source of unwanted signals is located in a tissue region, such as one of the atria or one of the ventricles. Regardless of the source, the unwanted signals are conducted elsewhere through cardiac tissue, where they can initiate or perpetuate the arrhythmia.

[0004] Procedures used to treat cardiac arrhythmias involve surgically disrupting the source of the arrhythmia-causing signals and the pathways used to conduct these signals. Recently, it has been discovered that by mapping the electrical properties of the endocardium and cardiac volumes and selectively ablating cardiac tissue through the application of energy, it is possible to stop or alter the propagation of unwanted electrical signals from one part of the heart to another. Ablation methods destroy unwanted electrical pathways by creating non-conductive lesions.

[0005] In this two-step procedure (mapping followed by ablation), electrical activity at various points in the heart is sensed and measured, typically by advancing a catheter containing one or more electrical sensors into the heart and acquiring data at multiple points. This data is then used to select a target area for ablation.

[0006] In order to achieve better mapping resolution, it is desirable that a mapping catheter provide very high density signal mapping by using multiple electrodes that sense electrical activity within a small area (e.g., one square centimeter). For mapping within the atria or ventricles (e.g., the apex of the ventricle), it is desirable that the catheter collect a larger amount of data signals within a shorter time span. It is also desirable that such a catheter be adaptable to different tissue surfaces, e.g., flat, curved, regular, or non-planar surface tissue, and be collapsible for atraumatic advancement and withdrawal through the patient's vascular system. Summary of the Invention

[0007] Various embodiments described herein allow for high-density mapping and / or ablation of tissue surfaces in the heart (including the atria or ventricles) using a catheter for electrophysiology applications. The catheter includes a tubular member and an end effector. The tubular member extends from a proximal portion to a distal portion along a longitudinal axis. The end effector is coupled to the distal portion. The end effector includes a first ring member, a second ring member, and a third ring member, each ring member including two ridges and a connector connecting the two ridges, and the first ring member, the second ring member, and the third ring member are configured such that each connector of each of the first ring member, the second ring member, and the third ring member contacts only one connector of an adjacent ring member.

[0008] In another embodiment, a catheter is designed for electrophysiology applications and includes a tubular member and an end effector. The tubular member extends from a proximal portion to a distal portion along a longitudinal axis. The distal portion of the tubular member includes a cross-section arranged around the longitudinal axis. The cross-section intersects a first orthogonal plane and a second orthogonal plane extending along the longitudinal axis. The cross-section of the distal portion includes a first opening and a second opening, the first opening and the second opening intersecting the first orthogonal plane and extending along the longitudinal axis, each of the openings being configured to receive a puller wire, and six holes being provided between the first opening and the second opening, four of which intersect the second orthogonal plane. Each of the holes is configured to receive a ridge member. The end effector is coupled to the distal portion. The end effector includes three closed-loop members, each ring including two ridges, such that the six ridge members of the three closed-loop members are disposed in corresponding six holes of the distal portion of the catheter.

[0009] In another embodiment, a catheter for electrophysiology applications is provided. The catheter includes a tubular member and an end effector. The tubular member extends from a proximal portion to a distal portion along a longitudinal axis. The distal portion of the tubular member has a cross-section arranged around the longitudinal axis, wherein the cross-section intersects a first orthogonal plane and a second orthogonal plane extending along the longitudinal axis. The cross-section of the distal portion includes a first opening and a second opening, the first opening and the second opening intersecting the first orthogonal plane and extending along the longitudinal axis, each of the openings being configured to receive a pull wire, and six holes being provided between the first opening and the second opening, wherein four holes intersect the second orthogonal plane. Each of the holes is configured to receive a spine member. The end effector is coupled to the distal portion of the tubular member. The end effector includes a first closed-loop member, a second closed-loop member, and a third closed-loop member. The end effector has an unconstrained configuration, wherein: the first closed-loop member includes a first spine connected to a second spine with a first ring connector portion to define a first generally flat surface between the first spine, the first ring, and the second spine, such that the first generally flat surface intersects the first and second orthogonal planes, the second closed-loop member includes a third spine connected to a fourth spine with a ring connector portion to define a second generally flat surface between the third, the second, and the fourth spine, such that the second generally flat surface intersects the first and second orthogonal planes, and the third closed-loop member includes a fifth spine connected to a sixth spine with a third ring connector portion to define a third generally flat surface, the third generally flat surface intersecting only one of the first and second orthogonal planes.

[0010] In another embodiment, a catheter for electrophysiology applications is provided. The catheter includes a tubular member, an end effector, and a coupling block. The tubular member extends along a longitudinal axis from a proximal portion to a distal portion. The end effector is coupled to the distal portion. The end effector includes a first ring member, a second ring member, and a third ring member, each ring member including two ridges and a connector connecting the two ridges; the coupling block is connected to each connector of the first ring member, the second ring member, and the third ring member. The coupling is configured to have a channel extending through the coupling block to allow for receiving each of the corresponding connectors of the first ring member, the second ring member, and the third ring member.

[0011] In another embodiment of a catheter for electrophysiology applications, the catheter includes a tubular member, an end effector, and a coupling block. The tubular member extends along a longitudinal axis from a proximal portion to a distal portion. The end effector is coupled to the distal portion, the end effector including a first ring member and a second ring member, each ring member including two ridges and a connector connecting the ridges; the coupling block is connected to each connector of the first and second ring members. The coupling is configured with a through-channel extending through the coupling block to accommodate each of the corresponding connectors of the first and second ring members.

[0012] In any of the foregoing embodiments, the following features may be combined with the embodiments and with each other in various arrangements, wherein each spine may include: a slender member providing structural support for the spine, each slender member being configured to have a rectangular cross-section extending from the distal portion to define a loop; the slender member comprising a shape memory material; the shape memory material comprising Nitinol; the Nitinol comprising cold-worked Nitinol and curled during assembly into the hole in the distal portion; each spine comprising a slender structure providing support for each spine; a plurality of electrodes coupled to each elongated structure, the plurality of electrodes being spaced apart at predetermined intervals relative to adjacent electrodes on each elongated structure and relative to electrodes on adjacent elongated structures, and the plurality of electrodes comprising a total of about 30 to about 100 electrodes, wherein the number of electrodes per elongated structure comprises about 5 to about 15 electrodes, and at least one of the plurality of electrodes is radiopaque; each spine comprising providing support for each spine The invention further comprises a plurality of electrodes disposed on each spine, the plurality of electrodes being spaced apart at predetermined intervals relative to adjacent electrodes on each spine and relative to electrodes on adjacent spines, the plurality of electrodes comprising a total of about 30 to about 100 electrodes, wherein the number of electrodes per spine comprises about 5 to about 15 electrodes; each connector for each ring member comprises at least one pair of electrodes disposed on the connector member, the pair of electrodes being configured for bipolar sensing of cardiac signals; a pair of reference electrodes disposed on the distal portion; at least one magnetic sensor disposed proximate the distal portion to enable determination of the position of the distal portion under the magnetic field; at least one impedance position sensor disposed proximate the distal portion of the tubular member to enable determination of the position of the distal portion based on measured impedance within the biological subject; the magnetic sensors comprising three single-axis magnetic sensors. Each ring member is configured to function as a magnetic sensor to enable determination of the position of each ring relative to the magnetic field under the magnetic field. At least one puller wire is disposed in the tubular portion and connected to the distal portion so that the at least one puller wire deflects the distal portion relative to the longitudinal axis; the at least one puller wire includes a first puller wire and a second puller wire that are substantially parallel, the first puller wire and the second puller wire are disposed in the tubular member and connected to the distal portion so that the first puller wire and the second puller wire deflect the distal portion in two directions relative to the longitudinal axis.

[0013] In some embodiments, dragging the distal electrode matrix can include maintaining a parallel arrangement of the matrix and / or maintaining at least a portion of the matrix flat on the tissue surface. Driving the distal electrode matrix can also include maintaining a predetermined relative spacing of the electrodes on the matrix. It is noteworthy that the terms "against," "on," "placed," and "located" as used herein do not limit the relative orientation of the distal electrode matrix and the tissue surface, including, for example, whether one or the other of the matrix and the tissue surface is above, below, or adjacent to the other. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] While claims are provided at the end of the specification which particularly point out and distinctly claim the subject matter described herein, it is believed that the subject matter will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0015] Figure 1 The catheter is shown from the actuator at the distal portion of the catheter to the proximal handle;

[0016] Figure 2A 、 Figure 2B and Figure 2C Shown separately Figure 1 Three other variations of the end effector;

[0017] Figure 2D and Figure 2E A side cross-sectional view and a cross-sectional view EE of the intermediate section 14 of the catheter are shown, respectively, to illustrate the various lumens and components within the lumens;

[0018] Figure 2F Shown Figure 1 Another variation of the end effector;

[0019] Figure 3 Shows the settings Figure 1 A perspective view of various components in the intermediate section 14 of the catheter;

[0020] Figure 4A 、 Figure 4B 、 Figure 4C 、 Figure 4D and Figure 4E shows the spatial configuration of the closed-loop member of the end effector when viewed from the proximal end of the catheter;

[0021] Figure 5A 、 Figure 5B 、 Figure 5C 、 Figure 5D 、 Figure 5E 、 Figure 5FVarious couplings are shown that can be used to ensure that the ring member of the end effector can be maintained in a desired spatial configuration when the end effector is not constrained for use with a delivery sheath;

[0022] Figure 6A and 6B shows a close-up perspective view of the structural backbone of each spine extending from an insertion member located in the distal portion of member 14 and the various wires and covers for the spines and electrodes mounted on each spine;

[0023] Figure 6C 、 Figure 6D and Figure 6E The asymmetric structural backbone and necessary cross-sections of the spines of the first and third ring members are shown;

[0024] Figure 6F 、 Figure 6G and Figure 6H showing the generally symmetrical structural backbone and necessary cross-sections of the spine for the second ring member;

[0025] Figure 7A 、 Figure 7B 、 Figure 7C and Figure 7D Various "grid-like" configurations and sizes of electrodes on each spine are shown; and

[0026] Figure 8 The deflection capability of the intermediate section 14 with puller wires is shown. DETAILED DESCRIPTION

[0027] The following detailed description should be read in conjunction with the accompanying drawings, in which the same elements are numbered the same in different drawings. The accompanying drawings (not necessarily drawn to scale) illustrate selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates the principles of the invention by way of example and not by way of limitation. This description will clearly enable those skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is currently believed to be the best mode of carrying out the invention.

[0028] As used herein, the terms "about" or "approximately" for any numerical values ​​or ranges indicate suitable dimensional tolerances that allow the component or collection of elements to achieve its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​±10% of the recited value, for example, "about 90%" may refer to a range of values ​​from 81% to 99%. Additionally, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject and are not intended to limit the systems or methods to human use, although use of the subject invention in human patients represents a preferred embodiment. The terms "proximal" and "distal" are used to reference the position of various components relative to the handle, which is designated as the nearest side to the user operating the handle.

[0029] like Figure 1 As shown, the catheter 10 includes an elongated catheter body 12, an intermediate deflection section 14, a distal electrode assembly or end effector 100, and a deflection control handle 16 attached to the proximal end of the catheter body 12. According to a feature of the present invention, the end effector 100 has a plurality of ridges 1A, 1B, 2A, 2B, 3A, 3B that are generally located in a common plane similar to a broom having bristles that are generally located in a common plane. The intermediate section is in the form of a tubular member 14 that extends from the proximal portion 12 to the distal portion 14A along a longitudinal axis LL. A distal electrode 38D and a proximal electrode 38P are provided proximate to the distal portion 14A so that both electrodes 38D and 38P can be matched (by masking a portion of one electrode and masking a different portion on the other electrode) to define a reference electrode (an electrode that does not contact tissue). One or more impedance sensing electrodes 38R are also provided to allow position sensing via impedance position sensing techniques as described in US Patents 5,944,022; 5,983,126; and 6,445,864, copies of which are provided in priority US Provisional Patent Application 62 / 841,154 and incorporated herein by reference.

[0030] The distal portion 14A is coupled to Figure 1 The end effector 100 in FIG. The end effector 100 has a first closed-loop member 1, a second closed-loop member 2, and a third closed-loop member 3. Each ring member (1, 2, or 3) has two ridges (A, B) and a connector (C) connecting the two ridges (nA, nB, where n represents the ridge of one ring). Therefore, the first ring member 1, the second ring member 2, and the third ring member 3 are configured so that each connector (C) of each of the first ring member 1, the second ring member 2, and the third ring member 3 contacts only one connector (C) of the adjacent ring members 1, 2, and 3. For example, as Figure 1As shown, spine 1A is connected to spine 1B via connector ring 1C to define a first ring member 1; spine 2A is connected to spine 2B via connector ring 2C to define a second ring member 2; and spine 3A is connected to spine 3B via connector ring 3C to define a third ring member 3. Figure 2A , only one connector 3C can contact two other connectors 1C and 2C, while Figure 2B In , each connector (1C, 2C, or 3C) can contact two other connectors (1C contacts connectors 2C and 3C; 2C contacts connectors 1C and 3C; 3C contacts connectors 2C and 1C). Figure 2C In the illustrated alternative embodiment, the three rings 1, 2, and 3 can be attached via sutures 150 so that when the end effector 100 is unconstrained or fully extended, the rings maintain their spatial configuration. As will be discussed below, there are 48 electrodes 37 arranged in a grid-like configuration, with at least four additional electrodes 37R disposed on connectors 1C, 2C, and 3C, and an additional electrode 37S disposed on the proximal side of the end effector. Electrodes 37R and 37S allow for signal coverage in configurations where grid electrodes cannot reach desired spatial locations. Furthermore, the spatial configuration of the three rings allows the electrode rings 37 to define a grid (dashed lines), allowing for the highest resolution capture of electrical signals propagating in orthogonal patterns (W1 and W2) due to the grid (square or rectangular) nature of the end effector 100. Figure 2F Another embodiment is shown in which an additional electrode 37R is provided at the distal end of the end effector 100' through the entire length of the curved connector rings 1C, 2C, and 3C.

[0031] Reference Figure 2D , the catheter body 12 can be an elongated tubular construction having a uniaxial channel or central lumen 18. The catheter body 12 is flexible, i.e., bendable, but substantially incompressible along its length. The catheter body 12 can have any suitable construction and can be made of any suitable material. In some embodiments, the catheter body 12 includes an outer wall 20 made of polyurethane or PEBAX. The outer wall 20 can include an embedded braided mesh of stainless steel, etc., to increase the torsional stiffness of the catheter body 12 so that when the control handle 16 is rotated, the intermediate section 14 of the catheter 10 will rotate in a corresponding manner.

[0032] The outer diameter of the catheter body 12 is not critical, but is preferably no greater than about 8 French, more preferably about 7 French. Likewise, the thickness of the outer wall 20 is also not critical, but is thin enough so that the central lumen 18 can accommodate at least one puller wire, one or more lead wires, and any other desired wires, cables, or tubes. If desired, the inner surface of the outer wall 20 is lined with a rigid tube 22 to provide improved torsional stability. In some embodiments, the outer wall 20 has an outer diameter of about 0.090 inches to about 0.94 inches and an inner diameter of about 0.061 inches to about 0.065 inches.

[0033] like Figure 2D and Figure 2E As shown, the intermediate section 14 comprises a shorter section of a tube 19 having multiple lumens, for example, four off-axis lumens 31, 32, 33, and 34. The first lumen 31 carries a plurality of leads 40S for the ring electrodes 37 carried on the spines 1A, 1B, 2A, 2B, 3A, and 3B. The second lumen 32 carries the first puller wire 24. The third lumen 33 carries a cable 36 for an electromagnetic position sensor 42 and a plurality of leads 40D and 40P for the distal and proximal ring electrodes 38D and 38P carried on the catheter proximal to the end effector 100. Electromagnetic position sensing technology is described in U.S. Patents 5,391,199; 5,443,489; 5,558,091; 6,172,499; 6,590,963; and 6,788,967. The magnetic position sensor 42 can be used with the impedance sensing electrode 38R in a hybrid magnetic and impedance position sensing technology called ACL described in the following patents: U.S. Patents 7,536,218; 7,756,567; 7,848,787; 7,869,865; and 8,456,182, copies of which are provided in priority U.S. Provisional Patent Application 62 / 841,154 and incorporated herein by reference.

[0034] See also Figure 2D and Figure 2E , a fourth lumen 34 (e.g., diametrically opposite the second lumen 32 in the illustrated embodiment) carries the second puller wire 26. The tube 19 is made of a suitable non-toxic material that is preferably more flexible than the catheter body 12. One suitable material for the tube 19 is braided polyurethane, i.e., a polyurethane having an embedded mesh of braided stainless steel or the like. The size of each lumen is not critical but is sufficient to accommodate guide wires, puller wires, cables, and any other components.

[0035] The usable length of the catheter, i.e., the portion that can be inserted into the body excluding the end effector, can vary as needed. Preferably, the usable length is in the range of about 110 cm to about 120 cm. The length of the intermediate section 14 is a relatively small portion of the usable length and is preferably in the range of about 3.5 cm to about 10 cm, more preferably in the range of about 5 cm to about 6.5 cm.

[0036] The catheter body 12 may be attached to an intermediate section 14, as described in U.S. Patent No. 9,820,664. Figure 2A and Figure 2B As shown and described (a copy of which is provided in priority U.S. Provisional Patent Application 62 / 841,154 and is incorporated herein by reference). If desired, a spacer (not shown) can be positioned within the catheter body between the distal end of the rigid tube (if provided) and the proximal end of the intermediate section. The spacer provides a flexible transition zone at the junction of the catheter body and the intermediate section that allows this junction to bend smoothly without folding or kinking. A catheter with such a spacer is described in U.S. Patent 5,964,757, a copy of which is provided in priority U.S. Provisional Patent Application 62 / 841,154 and is incorporated herein by reference.

[0037] like Figure 3 As shown in the perspective view of FIG, the end effector 100 includes a connector tube 46 mounted on the distal end of the tube 19 of the intermediate section 14 with the insert 200 for connecting the spine to the tubular member 14 ( Figure 4B The connecting tube 46 has a central lumen 48 that houses the various components. The outer peripheral notch 27 ( Figure 2D ) can be used to attach the connecting tube 46 and the intermediate segment 14, the outer peripheral recess receiving the inner surface of the proximal end of the connecting tube 46. The intermediate segment 14 and the connecting tube 46 are attached by glue or the like.

[0038] Likewise Figure 3 As shown, the connecting tube 46 houses various components, including the electromagnetic position sensor 42 and a distal anchor rod 51A for the puller wire 24 and another anchor rod 51B for the wire 26 ( Figure 3 Only the anchor 51B for the wire 26 is visible. A distal ring electrode 38D carried on the outer surface of the tube 19 near the distal end of the intermediate deflection segment 14 is connected to a lead formed in the sidewall of the tube 19. The distal end of the lead is welded or otherwise attached to the distal ring electrode 38D as is known in the art.

[0039] The end effector 100 extends from the distal end of the connecting tube 46. Figure 4AAs shown, wherein the plurality of ridges 1A, 1B, 2A, 2B, 3A, 3B all extend in different planes ( Figure 4C and Figure 4D The length of each ridge 1A, 1B, 2A, 2B, 3A, or 3B may be in the range of about 5 mm to 50 mm, preferably in the range of about 10 mm to 35 mm, and more preferably about 28 mm. The parallel distal portions 17D of each ridge 1A, 1B, 2A, 2B, 3A, or 3B (1A, 1B, 2A, 2B, 3A, 3B) may be spaced apart from each other by a distance in the range of about 1 mm to 20 mm, preferably in the range of about 2 mm to 10 mm, and more preferably about 4 mm.

[0040] The configuration of the ridges 1A, 1B, 2A, 2B, 3A and 3B of the rings 1, 2 and 3 for the unconstrained configuration is worth noting. Figure 4B 、 4C , 4D and 4E. Figure 4B , which is a cross-sectional view from the proximal end of the tubular member 14, provides a tubular insert 200 whose center coincides with the longitudinal axis LL. Orthogonal planes P1 and P2 are aligned with the longitudinal axis to define four quadrants in the insert 200. Figure 4B In the illustrated insert 200, holes 202, 204, 206, 208, 210, and 212 are provided for inserting the corresponding spines 1A, 2A, 3A, 3B, 1B, and 2B. It should be noted that the spines 1A, 3A, 3B, and 2B are generally disposed on an orthogonal plane P2, while the spines 2A and 1B are offset from the orthogonal planes P1 and P2. Openings 214 and 216 are provided on the orthogonal plane P1 for inserting puller wires or electrical wires and any other components to and from the end effector 100. With this arrangement of holes 202, 204, 206, 208, 210, and 212, the ring members 1, 2, and 3 are thus arranged in a unique, unconstrained arrangement, such as Figure 4C , as shown in cross-sectional view (when viewed from the proximal end), ring 3 defines a plane P3 (defined by ridges 3A and 3B and connector 3C) that intersects orthogonal plane P1, and ring 1 has a plane P4 (defined by ridges 1A and 1B and connector 3C) that intersects both orthogonal planes P1 and P2, and ring P2 has a plane P5 (defined by ridges 2A and 2B and connector 2C) that intersects both orthogonal planes P1 and P2.

[0041] exist Figure 4D In an alternative embodiment of insert 200, shown as insert 200' in FIG, the arrangement of holes 202, 204, 206, 208, 210, and 212 is different from Figure 4BSpecifically, the ridges 1A and 1B of the ring 1 are now received in the holes 202 and 208 so that the holes 202 and 208 (and the ridges 1A and 1B) are arranged in the same plane as the orthogonal plane P2 (instead of Figure 4B Ridges 3A and 3B are received in holes 206 and 212 on orthogonal plane P2. Ridges 2A and 2B are received in holes 204 and 210 that are offset relative to orthogonal plane P2. Figure 4D The arrangement of the holes, so that rings 1, 2 and 3 are arranged in Figure 4D (when viewed from the proximal end). Figure 4D In the example, rings 1, 2, and 3 are unconstrained ( Figure 4A ) or released from the delivery sheath. In the unconstrained configuration, the third ring 3 defines a plane P3 (extending between ridges 3A and 3B) that intersects both orthogonal planes P1 and P2; the first ring 1 defines a plane P4 (extending between ridges 1A and 1B) that intersects both orthogonal planes P1 and P2; and the second ring 2 defines a fifth plane P5 (extending between ridges 2A and 2B) that intersects only orthogonal plane P1. In summary, an insert 200 (or 200') is provided near the distal portion 14D, the insert having a first opening 214 and a second opening 216 that intersect the first orthogonal plane P1 and extend along the longitudinal axis LL, such that each of the openings 214 and 216 is configured to receive a puller wire (24 or 26). The insert 200 (or 200 ′) includes six holes 202, 204, 206, 208, 210, 212 disposed between a first opening 214 and a second opening 216, wherein four holes (206, 208) intersect the second orthogonal plane P2, each of the holes being configured to receive a spine member that collectively defines an end effector 100 coupled to the distal portion 14D. The end effector 100 has three closed-loop members, wherein each ring has two spines, such that the six spine members of the three closed-loop members are disposed in the corresponding six holes of the distal portion of the catheter.

[0042] It should be noted that the rings 1, 2, and 3 provided herein and their planar orientations enable position sensing of the rings themselves, as each ring acts as a single-axis magnetic coil. Utilizing three rings arranged in three spatial configurations, the rings can be used as a three-axis magnetic sensor to sense the magnetic field generated around a patient using the Carto3 mapping system. In short, each pair of ridges A and B is conductive and connected via connector C, terminating in different planar orientations ( Figure 4C or Figure 4E3) and encloses the area defined by the loop (1, 2, or 3). It will be understood that a particular loop acts as a coil with a single turn. Therefore, when the area enclosed by the single-turn coil (one loop) is passed through by an alternating magnetic field from a radiator placed around the subject, Faraday's law of induction dictates that an induced voltage is generated at the different second terminals of the pair, and that this voltage depends on the area of ​​the enclosed area, the magnetic field strength of the area, and the orientation of the area relative to the magnetic field.

[0043] Single-axis sensors (SAS) with multi-turn coils are known in the art, and if they are placed in a spatially mapped alternating magnetic field, it will be understood that the voltages generated across the SAS coils can be used to find the position and orientation of the SAS coils in the magnetic field. FIG. 6 of US20180344202 (a copy of which is provided in priority US Provisional Patent Application No. 62 / 841,154 and incorporated herein by reference) describes an algorithm for finding the position and orientation of a SAS in a mapped magnetic field, and those skilled in the art will be able to use the description of this algorithm, mutatis mutandis, to find the position and orientation of a single-turn coil, such as a specific single-turn coil defined by a pair of ridges (or loops). For n conductors, where n is an integer equal to or greater than 2, there are (n|2) different possible conductor pairs that form single-turn coils that generate (n|2) corresponding voltages. Therefore, for the six conductors considered here (in their respective splines), there are at least three possible single-turn coils. The voltage across each single-turn coil gives the coil's position and orientation, which is known or can be estimated. Based on the geometric relationships, and based on the voltages generated by the various single-turn coils, the processor in the CARTO3 system can estimate the position and orientation of the end effector 100. Each pair of opposing conductive ridges typically forms a planar ellipse of a total of three planar ellipses. Since the configuration of the ridges and rings is known (as provided herein), the orientation of the three rings 1, 2, and 3 relative to each other will be known, so this orientation can be used to calculate the orientation of the overall shape of the end effector 100. Details of a single conductive member (such as a ring used as a single-axis magnetic sensing coil) in combination with other rings are provided in U.S. patent application SN15 / 971,966, which was published as US20180344202, the entire contents of which are provided in priority U.S. provisional patent application 62 / 841,154, and are incorporated herein by reference.

[0044] Figures 4A to 4D The unique planar configuration of the end effector 100 in FIG. 1 presents some challenges in maintaining a substantially constant spacing between the ridges when the end effector 100 is unconstrained. Specifically, where connectors 1C, 2C, and 3C converge, it is beneficial to connect the rings together with a separate member such as, for example, a clamp 500, which is shown here as being in FIG. Figure 5AThe clamp 500 can be used to couple connectors 1C, 2C, and 3C together in a single connection point. Figure 5B and assembled with the end effector 100. Alternatively, the clamp 500 may be in the form of a circular ring. Figure 5D In the case of the arrangement shown), the coupling block 504 can be used to ensure that the connectors 1C, 2C and 3C are arranged in a fixed spatial configuration so that the first connector 1C extends through the first channel 504A, the second connector extends through the channel 504B, and the third connector 3C extends through the third channel 504C. Figure 5E 504B is shown in an enlarged perspective view of coupling block 504. Coupling block 504 includes a longitudinal axis L1 extending through the center of block 504. Plane PA (similar to orthogonal plane P1) is oriented such that plane PA extends along longitudinal axis L1 (similar to longitudinal axis LL) and bisects second channel 504B. Another plane PB, extending along axis L1 (similar to orthogonal plane P2) and orthogonal to plane PB, is defined such that four quadrants Q1, Q2, Q3, and Q4 can be defined as follows: quadrant Q1 is an upper left sector adjacent to or to the left of plane PB and adjacent to or above plane PA; quadrant Q2 is an upper right sector adjacent to or to the right of plane PA and adjacent to or above plane PB; quadrant Q3 is a lower right sector between the right of plane PA and adjacent to or below plane PB; and quadrant Q4 is a sector to the left of plane PA and adjacent to or below plane PB. Channel 504A extends from quadrant Q2 through coupling block 504 to quadrant Q4; channel 504B extends along plane PA through plane PB, such that channel 504B extends through all quadrants; and channel 504C extends from quadrant Q1 to quadrant Q3. It should be noted that clamp 500, ring 502, or coupling block 504 can be formed from a biocompatible material such as, for example, nitinol or a polymer. Biological agents (such as, for example, heparin or a suitable blood thinner) can be added to the nitinol or polymer to elute when in an organ or artery of a biological subject.

[0045] like Figure 6A and Figure 6B1B, 2A, and 2B are shown with the covers on ridges 1B and 2B removed so that the structural members 600 of ring 1 are visible. That is, each ring having ridges (1A, 1B, 1C, 2A, 2B, 2C, 3A, 3B, 3C) has an elongated shape memory member 600 that extends through the length of the ridge to and from the insert member 200. While the preferred embodiment has all three segments of the ring formed from a single unitary material (e.g., ring 1 having segment 1A, segment 1B, and segment 1C), it is within the scope of the present invention that the three segments can be separate components attached to one another. The proximal portion of each ring structural member 602 or 604 extends into the distal end portion of the connector tube 46 and is anchored to the insert 200 in the lumen 48 ( Figure 4B and Figure 4D To ensure that the rings 1, 2, and 3 can be compressed into a very small shape for delivery into a blood vessel, we designed the first ring 1 and the third ring 3 to have Figure 6C The structural member 602 is shown as having an asymmetric configuration, while the structural member 604 of the second ring 2 has Figure 6F The structural member 602 has a first portion 602A (forming the first ridge 1A or the third ridge 3A), a second portion 602B (forming the second ridge 1B or the third ridge 3B), and a connector portion 602C (forming the connector 1C or the connector 3C) connected to the two portions 604A and 604B. Figure 6F ) has a first portion 604A (forming the spine 2A) and a second portion 604B (forming the spine 2B), and a connector portion 604C (forming the connector 2C) connecting the two portions 604A and 604B. Figure 6DAs shown, the connector portion 604C has a rectangular cross-section with an area of ​​approximately 0.41 square millimeters, while the first portion 604A and the second portion 604B have a square cross-section of approximately 0.41 square millimeters. Given that the Nitinol wire is cold formed, the cross-sectional area does not change significantly. Therefore, the area moment of inertia of the Nitinol (along the X-axis and the Y-axis) is equal at the square Nitinol portion, and the bending stiffness ratio at the cold-formed portion of the Nitinol radius is about 4:1. Therefore, it takes about four times less force to bend the Nitinol in one plane at the ring radius than to bend it in another plane. The Nitinol is compression molded from the wire to obtain a rectangular or square cross-section. The preferred compressed Nitinol radius size is about 0.127 mm (about 0.005 inches) thick by 0.33 mm (about 0.013 inches) wide. In terms of thickness, the thickness ranges from 0.101 mm to about 0.152 mm (about 0.004 inches to about 0.006 inches), and in terms of width, the width ranges from about 0.28 mm to about 0.46 mm (about 0.011 inches to about 0.019 inches). The cross-section of the preferred Nitinol wire form for forming the loop is about 0.21 mm (about 0.008 inches by 0.008 inches) square. The range of Nitinol wire that can be used to form the loop is about 0.18 mm to about 0.25 mm (about 0.007 inches to 0.010 inches) square. Round wire with a diameter in the range of 0.18 mm to about 0.25 mm (0.007 inches - 0.010 inches) can also be used to form the loop.

[0046] Each spine 1A, 1B, 2A, 2B, 3A, or 3B1A, 1B, 2A, 2B, 3A, or 3B also has a non-conductive cover 64 covering the shape memory member 600, and each spine 1A, 1B, 2A, 2B, 3A, or 3B carries a plurality of annular electrodes 37, which may be a total of 48 to 124 electrodes. Thus, the end effector 100 carries a plurality of electrodes of about 48 to 64, preferably between about 48 and 100 electrodes, and more preferably about 48 electrodes. The surface area of ​​the end effector 100 may be about 10 cm 2 Up to 50cm 2 within a range of about 15 cm 2 and 25cm 2 and more preferably about 22.4 cm 2 In some embodiments, the electrode density is about 5 electrodes per square centimeter and the dimensions are about 0.7 mm x 0.7 mm.

[0047] With shape memory in its spines 1A, 1B, 2A, 2B, 3A, 3B, the end effector 100 can assume at least two configurations: a deployed configuration in which the spines 1A, 1B, 2A, 2B, 3A, 3B are in a deployed configuration. Figure 4B 、 4C , one of the configurations shown in 4D and 4E, and an expanded configuration, and a collapsed configuration, wherein the spines can be bundled together generally along the longitudinal axis LL.

[0048] The support member 600 is made of a material that has shape memory (i.e., it can temporarily straighten or bend from its initial shape when a force is applied and can substantially return to its initial shape after the force is no longer present or removed). One material suitable for the support member is a nickel / titanium alloy. Such alloys typically contain about 55% nickel and 45% titanium, but can also contain about 54% to about 57% nickel, with the remainder being titanium. Nickel / titanium alloy is nitinol, which has excellent shape memory as well as ductility, strength, corrosion resistance, resistivity and temperature stability. The non-conductive cover 64 can be made of any suitable material and is preferably made of a biocompatible plastic such as polyurethane or PEBAX. If desired, the support member 600 can be removed and the distal end of the non-conductive cover 64 can be preformed to have a desired curvature or configuration.

[0049] Each shape memory support member 600 extending through its corresponding non-conductive cover 64 has a proximal end connected by a suitable coupler (e.g., Figures 5A to 5F ) are received and anchored in the distal end of the connector tube 46. The leads 40S of the spine electrodes 37 extend through a protective distal polymeric tube 68D. They separate at the distal end of the connector tube 46 and extend into their respective non-conductive cover 64 of their respective spines 1A, 1B, 2A, 2B, 3A, 3B, alongside their respective shape memory members 600. Each lead 40S is connected to its respective spine ring electrode 37 through a respective opening (not shown) formed in the sidewall of the cover 64, through which the distal end of the lead reaches the exterior of the cover 64 and is welded or otherwise attached to its spine ring electrode 37, as is known in the art.

[0050] At the junction of the end effector 100 and the connector tube 46, the non-conductive cover 64 of each spine 1A, 1B, 2A, 2B, 3A, or 3B is attached at its proximal end and sealed to the tube 46 by a polyurethane adhesive or the like. If desired, the proximal end of the support member 600 may extend further proximally into the connector tube 46. Polyurethane or the like is additionally applied to the distal end of each spine to seal the distal end and provide an atraumatic dome.

[0051] As described above, the end effector 100 can assume at least two configurations: a deployed, expanded configuration ( Figure 5A ) and collapsed configurations (not shown). With the end effector 100 in the deployed expanded configuration, the proximal portion 17P of each spine is unfolded and generally extends in various planes, such as with respect to Figure 4C and Figure 4E 1B flares outward at a larger angle away from the longitudinal axis LL of the catheter, and the inner spines 3A and 1B flare outward at a smaller angle away from the longitudinal axis LL. With the end effector 100 in the collapsed configuration, the spines are bundled into a generally cylindrical form for delivery through the patient's anatomy via a suitable sheath.

[0052] The proximal ends of the leads 40S and 40D are electrically connected to a suitable connector (not shown) in the distal end of the control handle 16, which is connected to an input device for sensing electrical signals (e.g., electrocardiogram) generated in the tissue, thereby allowing the end effector to become a mapping catheter for mapping electrocardiogram signals. Alternatively, the electrode 37 can be connected to a source of ablation energy (e.g., RF energy) to perform ablation of the tissue, as is known in the art.

[0053] In the embodiment shown ( Figure 3 ), the lead wires 40S extending through the central lumen 18 of the catheter body 12 and the lumen in the deflection segment 14 can be enclosed in a protective sheath to prevent contact with other components in the catheter. The protective sheath can be made of any suitable material, preferably polyimide. As will be appreciated by those skilled in the art, the sheath can be eliminated as desired.

[0054] Ring electrodes 37 and 38D, 38P and 38R may be made of any suitable solid conductive material such as platinum or gold, preferably a combination of platinum and iridium, and may be mounted to non-conductive cover 64 and connector tube 46 using glue or the like. Alternatively, the ring electrodes may be formed by coating non-conductive cover 64 and connector tube 46 with a conductive material such as platinum, gold and / or iridium. The coating may be applied using sputtering, ion beam deposition or an equivalent technique.

[0055] The annular electrodes 37 on the ridges 1A, 1B, 2A, 2B, 3A, 3B may be spaced approximately evenly along each ridge. They may form any desired pattern, for example, a "rectangular grid" pattern ( Figure 7A 100 or Figure 7C 100") or a "square grid" pattern ( Figure 7B 100' and Figure 7D 100"'). Figure 7A In the rectangular grid, the electrodes 37 are spaced apart at intervals "i" of approximately 2 mm along the longitudinal axis LL and at intervals "t" of approximately 2.7 mm transverse to the longitudinal axis LL, while Figure 7C In the embodiment of , the spacing "i" is about 2 mm and the lateral spacing "t" is about 2.4 mm. Figure 7B In the square grid, the interval "i" is about 2.7 mm and the interval "t" is about 2.4 mm, while in Figure 7D , the interval "i" is equal to the interval "t" of about 2.4 mm.

[0056] In another embodiment, each spine may have a "paired" electrode consisting of a closely spaced pair of ring electrodes. As used herein, the term "ring electrode pair" refers to a pair of ring electrodes that are closer together than to other adjacent ring electrodes. In some embodiments, the distance between the two electrodes of an electrode pair is less than about 3 mm, more preferably less than about 2 mm, and even more preferably from about 0.5 mm to about 1.5 mm. The number of electrode pairs can vary as desired and preferably ranges from 3 to 36 pairs, more preferably 24 pairs.

[0057] The end effector 100 can carry, for example, 24 pairs ( Figure 1 、 2A , 2B, 2C or 2D), with the spacing between the two electrodes of each pair being about 1 mm to about 2 mm. Preferably, each ring electrode 37 is relatively short, having a length 37L in the range of about 0.4 mm to about 0.75 mm. Regardless of the size and number of the ring electrodes 37, the electrode pairs are approximately evenly spaced along the end effector 100. The closely spaced electrode pairs allow for more accurate detection of the near-field pulmonary vein potential relative to the far-field atrial signal, which is very important when attempting to treat atrial fibrillation. Specifically, the near-field pulmonary vein potential is a very small signal, while the atria, located in close proximity to the pulmonary veins, provide a much larger signal. Therefore, even when the mapping array is placed in the pulmonary vein area, it may be difficult for the physician to determine whether the signal is a small near potential (from the pulmonary veins) or a larger more distal potential (from the atria). The closely spaced bipoles allow the physician to more accurately determine whether he is looking at a near signal or a distal signal. Therefore, by having closely spaced electrodes, it is possible to precisely target the location of cardiac tissue with pulmonary vein potential, thereby allowing clinicians to deliver therapy to specific tissue. In addition, closely spaced electrodes allow physicians to determine the precise anatomical location of the heart's ostium through electrical signals.

[0058] The electromagnetic position sensor 42 is housed in the lumen of the non-conductive cover 46 ( Figure 3 ). A sensor cable 36 extends from the proximal end of the position sensor 42 and passes through the central lumen 18 of the catheter body 12. The cable 36 is attached to a printed circuit board in the control handle 16 as is known in the art.

[0059] Puller wires 24 and 26 (whether as two separate tensile members or components of a single tensile member) are provided to achieve bidirectional deflection of the intermediate section 14. Puller wire 24 ( Figure 6A ) and 26( Figure 3) is actuated by a mechanism in the control handle 16 that is responsive to the thumb control knob or deflection control knob 11. Suitable control handles are disclosed in the following patents: U.S. Patents 6,123,699; 6,171,277; 6,183,435; 6,183,463; 6,198,974; 6,210,407; and 6,267,746, the entire disclosures of which are provided in priority U.S. Provisional Patent Application 62 / 841,154 and are incorporated herein by reference.

[0060] The details of the construction of the puller wire (comprising the anchoring member of the T-bar via the intermediate section 14) are as known in the art and are described in, for example, U.S. Patents 8,603,069 and 9,820,664, the entire contents of which are incorporated herein by reference. In either case, the puller wires 24 and 26 are all made of any suitable metal, such as stainless steel or nitinol, and are each preferably coated with Teflon etc. The coating imparts lubricity to the puller wire. The diameter of the puller wire is preferably in the range of approximately 0.006 inch to approximately 0.010 inch.

[0061] In use, a suitable guide sheath (not shown) is inserted into the patient's body, with the distal end of the guide sheath positioned at or near a desired tissue location for diagnosis, such as mapping, and / or treatment, such as ablation. An example of a suitable guide sheath that may be used in connection with the present invention is the Preface Braided Guiding Sheath, which is commercially available from Biosense Webster, Inc. (Irvine, Calif.). The catheter 10 is passed through the guide sheath and advanced therethrough to the desired tissue location. Specifically, the spines 1A, 1B, 2A, 2B, 3A, 3B of the end effector 100 are collapsed and straightened and fed into the proximal end of the guide sheath. After the end effector 100 has reached the desired tissue location, the guide sheath is pulled proximally as needed to expose at least the spines 1A, 1B, 2A, 2B, 3A, 3B (if not also the deflectable intermediate stage 14). Outside of the guide sheath 36, the spines 1A, 1B, 2A, 2B, 3A, 3B assume a deployed configuration in which each spine is expanded and positioned approximately Figure 4C and Figure 4D The end effector 100 has a first side 100A and a second side 100B ( Figure 4C 、 Figure 4D and Figure 8 This allows the user to place the first side 100A (or 100B) against a tissue surface with at least the intermediate section 14 (if not also the distal portion of the catheter body 12) generally perpendicular to the tissue surface, and actuate the control handle to deflect the intermediate deflection section 14 to obtain various deflections or radii of curvature (e.g., Figure 8 ), causing the second side 100B to deflect back toward the catheter, which may allow the second side 100B of the end effector 100, including loops 1, 2, and 3, to be dragged across the tissue surface as the segment 14 deflects.

[0062] In use, the spine electrodes 37 contact the tissue surface, thereby maintaining a generally consistent separation spacing from one another within the distal electrode matrix as the spines are dragged across the tissue surface for high-density electrode sensing and uniform and predictable mapping. In accordance with a feature of the present invention, the end effector 100 has an "n×m" electrode layout or arrangement, for example, four spines with eight electrodes on each spine for a total of 48 closely spaced spine electrodes for mapping.

[0063] In some embodiments, the distal ring electrode 38D and the proximal ring electrode 38P are used as reference electrodes for visualization of the catheter on a 3-D mapping system, such as CARTO. The 3SYSTEM, available from Biosense Webster, Inc., automatically positions the electromagnetic sensor 42, processes the reference position values ​​from the electrodes 38D and 38P, which are in a constant position relative to the electromagnetic sensor 42, and determines the position of the spine electrode 37 and visualizes the rest of the electrode end effector 100.

[0064] The foregoing description has been presented with reference to the presently preferred embodiments of the invention. Those skilled in the art to which the invention pertains will appreciate that changes and modifications may be made to the structures described without intentionally departing from the principles, spirit and scope of the invention. As will be appreciated by those skilled in the art, the drawings are not necessarily drawn to scale. In addition, the different features of the different embodiments may be combined as desired or appropriate. Furthermore, the catheters described herein may be configured to apply various forms of energy, including microwaves, lasers, radiofrequency and / or cryogens. Therefore, the foregoing specific embodiments should not be interpreted as being suitable only for the precise structures described and shown in the accompanying drawings, but rather should be interpreted as being consistent with and supporting the following claims, which have the full and fair scope of the invention.

Claims

1. A catheter for electrophysiology applications, comprising: a tubular member extending along a longitudinal axis from a proximal portion to a distal portion; as well as An end actuator is connected to the distal portion, the end actuator comprising a first ring member, a second ring member and a third ring member, each ring member comprising two ridges and a connector connecting the two ridges, wherein each ring member is configured to function as a magnetic sensor so that the position of each ring member relative to the magnetic field can be determined under a magnetic field, and the first ring member, the second ring member and the third ring member are configured so that only one connector of the first ring member, the second ring member and the third ring member contacts the other two connectors.

2. The catheter of claim 1 , wherein the distal portion has a cross-section disposed about the longitudinal axis, the cross-section intersecting a first orthogonal plane and a second orthogonal plane extending along the longitudinal axis, the cross-section of the distal portion comprising a first opening and a second opening intersecting the first orthogonal plane and extending along the longitudinal axis, each of the openings being configured to receive a puller wire; six apertures disposed between the first opening and the second opening, wherein four apertures intersect the second orthogonal plane, each of the apertures being configured to receive a spine member; The first ring member is a first closed-loop member, the second ring member is a second closed-loop member, and the third ring member is a third closed-loop member, wherein the six spine members of the first closed-loop member, the second closed-loop member and the third closed-loop member are disposed in corresponding six holes of the distal portion of the catheter.

3. The catheter of claim 1 , wherein the distal portion has a cross-section disposed about the longitudinal axis, the cross-section intersecting a first orthogonal plane and a second orthogonal plane extending along the longitudinal axis, the cross-section of the distal portion comprising a first opening and a second opening intersecting the first orthogonal plane and extending along the longitudinal axis, each of the openings being configured to receive a puller wire; six apertures disposed between the first opening and the second opening, wherein four apertures intersect the second orthogonal plane, each of the apertures being configured to receive a spine member; wherein the first ring member is a first closed-loop member, the second ring member is a second closed-loop member, and the third ring member is a third closed-loop member, the end effector having an unconstrained configuration, wherein: the first closed-loop member comprising a first spine connected to a second spine with a first ring connector portion to define a first generally planar surface between the first spine, the first ring connector portion, and the second spine, such that the first generally planar surface intersects the first and second orthogonal planes, the second closed-loop member includes a third spine connected to a fourth spine with a second ring connector portion to define a second generally planar surface between the third spine, the second ring connector portion, and the fourth spine, such that the second generally planar surface intersects the first and second orthogonal planes, and The third closed-loop member includes a fifth ridge connected to a sixth ridge with a third loop connector portion to define a third generally planar surface that intersects only one of the first and second orthogonal planes.

4. The catheter of claim 1 , further comprising a coupling block connected to each connector of the first, second, and third ring members, the coupling block being configured to have a channel extending therethrough to permit receipt of each of the corresponding connectors of the first, second, and third ring members.

5. The catheter of claim 1 , wherein each ridge comprises: Elongated members provide structural support to the spine, each elongated member being configured to have a rectangular cross-section extending from the distal portion to define a loop. The catheter of claim 5 , wherein the elongated member comprises a shape memory material. The catheter of claim 6 , wherein the shape memory material comprises Nitinol.

8. The catheter of claim 7, wherein the nitinol comprises cold worked nitinol and is crimped during assembly into the bore of the distal portion.

9. The catheter of claim 1 , wherein each ridge comprises: an elongated structure providing support for each ridge; a plurality of electrodes coupled to each elongated structure, the plurality of electrodes being spaced apart at predetermined intervals relative to adjacent electrodes on each elongated structure and relative to electrodes on adjacent elongated structures, and the plurality of electrodes comprising a total of 30 to 100 electrodes, wherein the number of electrodes per elongated structure is 5 to 15; and At least one electrode of the plurality of electrodes is radiopaque.

10. The catheter of claim 1 , wherein each ridge comprises: an elongated structure providing support for each ridge; A plurality of electrodes are disposed on each ridge, the plurality of electrodes being spaced apart at predetermined intervals relative to adjacent electrodes on each ridge and relative to electrodes on adjacent ridges, and the plurality of electrodes comprising a total of 30 to 100 electrodes, wherein the number of electrodes per ridge is 5 to 15.

11. The catheter of claim 10, wherein each connector for each ring member comprises: At least one pair of electrodes is disposed on the connector member, the pair of electrodes being configured for bipolar sensing of cardiac signals.

12. The catheter of claim 11, wherein at least one pair of electrodes comprises at least two pairs of electrodes on each connector member connecting the two spines of each ring.

13. The catheter of claim 10, further comprising a pair of reference electrodes disposed on the distal portion.

14. The catheter of claim 1, further comprising at least one magnetic sensor disposed proximate to the distal portion such that a position of the distal portion can be determined under a magnetic field.

15. The catheter of claim 1, 2, 3, 4 or 13, further comprising at least one impedance position sensor disposed proximate the distal portion of the tubular member to allow determination of the position of the distal portion based on measured impedance within the biological subject.

16. The catheter of claim 14, wherein the magnetic sensor comprises three single-axis magnetic sensors.

17. The catheter of claim 1, further comprising at least one puller wire disposed in the tubular portion and connected to the distal portion such that the at least one puller wire deflects the distal portion relative to the longitudinal axis.

18. The catheter of claim 17, wherein the at least one puller wire comprises a first puller wire and a second puller wire that are substantially parallel, the first puller wire and the second puller wire being disposed in the tubular member and connected to the distal portion such that the first puller wire and the second puller wire deflect the distal portion in two directions relative to the longitudinal axis.

19. The catheter of claim 18, wherein the first puller wire deflects the distal portion relative to the longitudinal axis to define a first radius of curvature, and the second puller wire deflects the distal portion relative to the longitudinal axis to define a second radius of curvature that is smaller than the first radius of curvature.

20. A catheter for electrophysiology applications, the catheter comprising: a tubular member extending along a longitudinal axis from a proximal portion to a distal portion; an end effector coupled to the distal portion, the end effector comprising a first ring member and a second ring member, each ring member comprising two spines and a connector connecting the two spines, wherein each ring member is configured to function as a magnetic sensor such that a position of each ring member relative to a magnetic field can be determined under a magnetic field; as well as A coupling block is connected to each connector of the first and second ring members, the coupling block being configured with a through passage extending therethrough to permit receipt of each of the corresponding connectors of the first and second ring members.

21. The catheter of claim 20, further comprising at least one impedance position sensor disposed proximate the distal portion of the tubular member to allow determination of the position of the distal portion based on measured impedance within the biological subject.

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