Unipolar reference electrode for electrophysiological mapping catheter

Abstract

The present invention is entitled "Monopolar Reference Electrode for Electrophysiology Mapping Catheter". The present invention provides a device comprising a shaft and an end effector at the distal end of the shaft. The end effector has a distal end and a proximal end with a longitudinal midpoint between the distal end and the proximal end. The end effector is sized to fit in an anatomical passage within the cardiovascular system. The end effector comprises at least one sensor electrode and a reference electrode. The at least one sensor electrode is configured to contact cardiovascular tissue and thereby acquire an electrical potential. The reference electrode is configured to acquire an electrical potential from a fluid in contact with the reference electrode. The reference electrode is located proximal to the longitudinal midpoint of the end effector. The end effector is configured to prevent the reference electrode from contacting tissue.

Description

Background Art

[0001] Arrhythmias, such as atrial fibrillation, occur when an area of cardiac tissue conducts electrical signals abnormally. Procedures for treating arrhythmias include surgically interrupting the conduction pathways for such signals. By applying energy (e.g., radiofrequency (RF) energy) to selectively ablate cardiac tissue, it is possible to stop or alter the propagation of unwanted electrical signals from one part of the heart to another. The ablation process can provide a barrier to the unwanted electrical pathways by creating electrical insulation lesions or scar tissue.

[0002] In some procedures, a catheter with one or more RF electrodes can be used to provide ablation within the cardiovascular system. The catheter can be inserted into a major vein or artery (e.g., the femoral artery) and then advanced to position the electrode within the heart or in a cardiovascular structure adjacent to the heart (e.g., the pulmonary vein). The electrode can be placed in contact with cardiac tissue or other vascular tissue and then activated with RF energy, thereby ablating the contacted tissue. In some cases, the electrode can be bipolar. In some other cases, a monopolar electrode can be used in combination with a ground pad that contacts the patient.

[0003] Examples of ablation catheters are described in U.S. Publication 2013 / 0030426, published on January 31, 2013, entitled “Integrated Ablation System using Catheter with Multiple Irrigation Lumens,” the disclosure of which is incorporated herein by reference; U.S. Publication 2017 / 0312022, published on November 2, 2017, entitled “Irrigated Balloon Catheter with Flexible Circuit Electrode Assembly,” the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0071017, published on March 15, 2018, entitled “Ablation Catheter with a Flexible Printed Circuit Board,” the disclosure of which is incorporated herein by reference; and U.S. Publication 2018 / 0071017, published on March 1, 2018, entitled “Catheter with Bipole Electrode Spacer and and U.S. Patent No. 8,956,353, entitled “Electrode Irrigation Using Micro-Jets,” published on February 17, 2015, the disclosure of which is incorporated herein by reference; and U.S. Patent No. 8,956,353, entitled “Electrode Irrigation Using Micro-Jets,” published on October 31, 2017, the disclosure of which is incorporated herein by reference; and U.S. Patent No. 8,956,353, entitled “Electrode Irrigation Using Micro-Jets,” published on October 31, 2017, the disclosure of which is incorporated herein by reference; and U.S. Patent No. 8,956,353, entitled “Electrocardiogram Noise Reduction and Irrigation,” published on February 8, 2018, the disclosure of which is incorporated herein by reference; No. 9,801,585 for "ECG Noise Reduction," the disclosure of which is incorporated herein by reference.

[0004] Some catheter ablation procedures may be performed using electrophysiological (EP) mapping. Such EP mapping may include the use of sensing electrodes on a catheter (e.g., the same catheter used to perform the ablation). Such sensing electrodes can monitor electrical signals within the cardiovascular system to precisely determine the location of abnormally conductive tissue sites that cause arrhythmias. An example of an EP mapping system is described in U.S. Patent No. 5,738,096, entitled “Cardiac Electromechanics,” issued on April 14, 1998, the disclosure of which is incorporated herein by reference. Examples of EP mapping catheters are described in U.S. Patent 9,907,480, published on March 6, 2018, entitled “Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes,” the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0036078, published on February 8, 2018, entitled “Catheter with Soft Distal Tip for Mapping and Ablating Tubular Region,” the disclosure of which is incorporated herein by reference; and U.S. Publication 2018 / 0056038, published on March 1, 2018, entitled “Catheter with Bipole Electrode Spacer and Related Methods,” the disclosure of which is incorporated herein by reference.

[0005] In addition to using EP mapping, some catheter ablation procedures can also be performed using image-guided surgery (IGS) systems. An IGS system can enable a physician to visually track the position of a catheter within a patient relative to an image of the patient's anatomy in real time. Some systems can provide a combination of EP mapping and IGS functionality, including the CARTO® system offered by Biosense Webster, Inc. of Irvine, California. Examples of catheters configured for use with the IGS system are disclosed in U.S. Patent 9,480,416, issued on November 1, 2016, entitled “Signal Transmission Using Catheter Braid Wires,” the disclosure of which is incorporated herein by reference; and various other references cited herein.

[0006] While several surgical systems and methods have been made and used, it is believed that no one prior to the inventors has made or used the invention described in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The following drawings and detailed description are intended to be illustrative only and are not intended to limit the scope of the invention as contemplated by the inventors.

[0008] Figure 1 A schematic diagram illustrating a medical procedure for inserting a catheter of a catheter assembly into a patient;

[0009] Figure 2 Shown Figure 1 a top plan view of a catheter assembly;

[0010] Figure 3 Shown Figure 1 a perspective view of an end effector of a catheter assembly;

[0011] Figure 4 Shows contact with tissue surface Figure 3 A side view of the end effector;

[0012] Figure 5 Shown Figure 1 a perspective view of an end portion of a distal end portion of a catheter assembly with an end effector arm omitted, and wherein a schematic diagram of an end effector profile includes a cylindrical portion and a flared frusto-conical portion;

[0013] Figure 6 Shown Figure 1 a perspective view of an end portion of a distal end portion of a catheter assembly wherein an end effector arm is omitted, and wherein a schematic diagram of an end effector profile includes a cylindrical portion and a pyramidal frusto-conical portion;

[0014] Figure 7 Shown Figure 3 A partial side elevation view of an end effector of FIG, wherein one arm is in a three-segment configuration and wherein the other arms are omitted;

[0015] Figure 8 Shown can be combined with Figure 1 A side elevation view of an exemplary alternative end effector in a catheter assembly;

[0016] Figure 9 Shown Figure 8 an enlarged side view of a portion of a central shaft of an end effector;

[0017] Figure 10 Shown can be combined with Figure 1A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0018] Figure 11 Shown can be combined with Figure 1 A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0019] Figure 12 Shown can be combined with Figure 1 A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0020] Figure 13 Shown can be combined with Figure 1 A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0021] Figure 14 Shown can be combined with Figure 1 A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0022] Figure 15 Shown can be combined with Figure 1 A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0023] Figure 16 Shown can be combined with Figure 1 A side elevation view of another exemplary alternative end effector in a catheter assembly;

[0024] Figure 17 Shown can be combined with Figure 10-16 an enlarged perspective view of a tip of a catheter assembly;

[0025] Figure 18 Shown can be combined with Figure 1 A perspective view of another exemplary alternative end effector in a catheter assembly;

[0026] Figure 19 Shown can be combined with Figure 1 A perspective view of another exemplary alternative end effector in a catheter assembly of FIG; and

[0027] Figure 20 Shown can be combined with Figure 1 A perspective view of another exemplary alternative end effector in a catheter assembly. DETAILED DESCRIPTION

[0028] The following description of some examples of the present invention should not be used to limit the scope of the present invention. The accompanying drawings (not necessarily drawn to scale) illustrate selected embodiments and are not intended to limit the scope of the present invention. The detailed description illustrates the principle of the present invention by way of example and not by way of limitation. According to the following description shown by way of example, other examples, features, aspects, embodiments and advantages of the present invention will be apparent to those skilled in the art, and a best approach is envisioned for implementing the present invention. As will be appreciated, the present invention can have other different or equivalent aspects, all of which do not depart from the present invention. Therefore, the drawings and description should be considered to be illustrative and not restrictive in nature.

[0029] Any one or more of the teachings, expressions, versions, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, versions, examples, etc. described herein. Therefore, the following teachings, expressions, versions, examples, etc. should not be considered separate from one another. Various suitable ways in which the teachings herein may be combined will be apparent to those skilled in the art with reference to the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

[0030] As used herein, the term "about" or "approximately" with respect to any numerical value or range indicates an appropriate dimensional tolerance that allows the component or collection of components to function for its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of ±10% of the recited value, for example, "about 90%" can 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 systems or methods to human use, although use of the subject invention in human patients represents a preferred embodiment.

[0031] I. Exemplary Mapping Catheter Systems

[0032] A. Overview

[0033] Some EP mapping procedures may be performed using monopolar electrodes. Some conventional monopolar EP mapping techniques may include comparing the potential acquired by one monopolar electrode to the potential acquired by a remote reference electrode. An example of such a technique is the Wilson Central Terminal (WCT), which includes averaging three limb leads. Another technique may include using electrodes on a first catheter to acquire the potential at a tissue region of interest and using electrodes on a second catheter to acquire a reference potential. For example, the electrodes on the first catheter may acquire the potential at tissue in the pulmonary vein (PV), while the electrodes on the second catheter may acquire the reference potential in the inferior vena cava (IVC).

[0034] As an alternative to conventional unipolar EP mapping techniques, it may be desirable to obtain a reference potential from the blood near the tissue from which the tissue potential is acquired. In other words, it may be desirable to place a first electrode in contact with the tissue, thereby acquiring the potential from the tissue; and to place a second electrode in contact with the blood near the contacted tissue, thereby acquiring the reference potential from the blood. The second (reference) electrode may only contact the blood and not the tissue. The blood can provide an accurate reference potential for the heart. By avoiding contact with the tissue, the second (reference) electrode avoids acquiring local tissue potentials, which could otherwise compromise the reliability of the sensed reference potential. This configuration can provide similar benefits to those achieved using bipolar EP mapping devices and techniques, such as reduced noise and reduced far-field signal, due to the reference electrode being located in the same ventricle as the tissue-contacting electrode; while still maintaining the characteristics of a unipolar signal, as the direct tissue potential is acquired by only a single electrode. By way of example only, this configuration can provide a reduction in far-field signal of approximately 50% to approximately 100% compared to far-field signals acquired using conventional techniques such as WCT.

[0035] Figure 1 An exemplary medical procedure and associated components of a cardiac EP mapping catheter system that can be used to provide non-conventional unipolar EP mapping as described above are shown. Specifically, Figure 1 A physician (PH) is shown grasping the handle (110) of the catheter assembly (100) wherein the catheter (120) of the catheter assembly (100) (at Figure 2-4 Shown but not in Figure 1 The end effector (130) is positioned within a patient (PA) to perform EP mapping in or near a heart (H) of the patient (PA). Figure 2 As shown in FIG, a catheter (120) includes an elongated flexible shaft (122) with an end effector (130) disposed at a distal end (124) of the shaft (122). The end effector (130) and variations thereof will be described in more detail below. The catheter assembly (100) is coupled to the guidance and drive system (10) via a cable (30). The catheter assembly (100) is also connected to a fluid source (42) via a fluid conduit (40), but this is merely optional. A set of field generators (20) are positioned below the patient (PA) and are coupled to the guidance and drive system (10) via another cable (22). The field generators (20) are also merely optional.

[0036] The guidance and drive system (10) of this example includes a console (12) and a display (18). The console (12) includes a first driver module (14) and a second driver module (16). The first driver module (14) is coupled to the catheter assembly (100) via a cable (30). In some variations, the first driver module (14) can be operated to receive EP mapping signals obtained via electrodes (132, 146, 148, 154) of an end effector (130), as described in more detail below. The console (12) includes a processor (not shown) that processes such EP mapping signals and thereby provides EP mapping as known in the art. In addition or alternatively, the first driver module (14) can be operated to provide RF power to the electrodes (132, 146, 148) of the end effector (130), thereby ablating tissue. In some versions, first driver module (14) is further operable to receive a position-indicative signal from a position sensor (not shown) in end effector (130), as described in greater detail below. In this version, a processor of console (12) is further operable to process the position-indicative signal from the position sensor to determine the position of end effector (130) of catheter (120) within the patient (PA).

[0037] The second driver module (16) is coupled to the field generator (20) via a cable (22). The second driver module (16) is operable to activate the field generator (20) to generate an alternating magnetic field around the heart (H) of the patient (PA). For example, the field generator (20) may include a coil that generates the alternating magnetic field in a predetermined working volume that accommodates the heart (H).

[0038] As described above, some versions of the end effector (130) include a position sensor (not shown) operable to generate a signal indicating the position and orientation of the end effector (130) within the patient (PA). Each position sensor may include a coil or a plurality of wire coils (e.g., three orthogonal coils) configured to generate an electrical signal in response to the presence of an alternating electromagnetic field generated by the field generator (20). Other components and techniques that may be used to generate real-time position data associated with the end effector (130) may include wireless triangulation, acoustic tracking, optical tracking, inertial tracking, and the like. By way of example only, position sensing may be provided in accordance with at least some of the teachings of U.S. Patent No. 9,480,416, the disclosure of which is incorporated herein by reference. Alternatively, the end effector (130) may be devoid of a position sensor.

[0039] The display (18) is coupled to the processor of the console (12) and is operable to render an image of the patient's anatomy. Such images may be based on a set of images obtained before or during surgery (e.g., CT or MRI scans, 3D maps, etc.). The view of the patient's anatomy provided by the display (18) may also be dynamically changed based on a signal from a position sensor of the end effector (130). For example, as the end effector (130) of the catheter (120) moves within the patient (PA), the corresponding position data from the position sensor may cause the processor of the console (12) to update the view of the patient's anatomy in the display (18) in real time to depict the area of the patient's anatomy around the end effector (130) as the end effector (130) moves within the patient (PA). In addition, the processor of the console (12) may drive the display (18) to display the location of abnormal conductive tissue sites as detected by EP mapping using the end effector (130). By way of example only, the processor of console (12) may drive display (18) to superimpose the location of the abnormal conductive tissue site on an image of the patient's anatomy, such as by superimposing an illuminated dot, crosshairs, or some other form of visual indication of the abnormal conductive tissue site.

[0040] The processor of the console (12) can also drive the display (18) to superimpose the current position of the end effector (130) on the image of the patient's anatomy, such as by superimposing an illuminated dot, a crosshair, a graphical representation of the end effector (130), or some other form of visual indication. As the physician moves the end effector (130) within the patient (PA), such superimposed visual indication can also move within the image of the patient's anatomy on the display (18), thereby providing the operator with real-time visual feedback regarding the position of the end effector (130) within the patient (PA) as the end effector (130) moves within the patient (PA). Thus, the image provided by the display (18) can effectively provide a video tracking the position of the end effector (130) within the patient (PA) without necessarily having any optical instrument (i.e., a camera) to observe the end effector (130). In the same view, the display (18) can simultaneously visually indicate the location of abnormal conductive tissue sites detected by EP mapping as described herein. The physician (PH) may thus view the display (18) to observe the real-time positioning of the end effector (130) relative to the mapped abnormal conductive tissue site and relative to an image of adjacent anatomical structures within the patient (PA).

[0041] The fluid source (42) of this example comprises a bag containing saline or some other suitable irrigation fluid. The conduit (40) comprises a flexible tube that is also coupled to a pump (44) that is operable to selectively drive fluid from the fluid source (42) to the catheter assembly (100). In some variations, the conduit (40), fluid source (42), and pump (44) are omitted entirely. In versions that include these components, the end effector (130) can be configured to deliver irrigation fluid from the fluid source (42) to a target site within the patient's body. Such irrigation can be provided in accordance with the teachings of any of the various patent references cited herein; or in any other suitable manner that would be apparent to one skilled in the art having reference to the teachings herein.

[0042] B. Exemplary Multi-Ray End Effector with Reference Electrode on Irrigation Shaft

[0043] Figure 2-4 The end effector (130) is shown in more detail. In addition to the following, the end effector (130) and other aspects of the catheter assembly (100) can be configured and operated according to at least some of the teachings of U.S. Publication 2018 / 0056038, the disclosure of which is incorporated herein by reference. As shown, the end effector (130) of this example includes a set of ridges or arms (140) extending distally from the distal end of the catheter shaft (122). The arms (140) typically radiate outwardly away from the central longitudinal axis (LL) of the catheter shaft (122). In this example, the end effector (130) has five arms (140). In some other versions, the end effector (130) has eight arms (140). Alternatively, the end effector (130) may have any other suitable number of arms (140).

[0044] Each arm (140) includes a flexible, elongated body (142) having a corresponding set of longitudinally spaced pairs of annular electrodes (146, 148). Each arm (140) terminates distally at a corresponding free end. In the present example, each arm (140) has four pairs of electrodes (146, 148). Alternatively, more or less than four pairs of electrodes (146, 148) may be provided on each arm (140). The electrodes (146, 148) of each pair are separated from each other by corresponding gaps (144). In the present example, each pair of electrodes (146, 148) is configured to provide bipolar sensing of electrocardiogram signals when the electrodes (146, 148) are placed in contact with cardiovascular tissue. Each pair of electrodes (146, 148) may also be used to provide unipolar sensing; alternatively, only a single electrode (146, 148) in each pair may be used to provide unipolar sensing without using the other electrode (146, 148) in the pair. The catheter assembly (100) may also enable the physician (PH) to switch the end effector (130) between two or more modes, including a bipolar sensing mode and a unipolar sensing mode. In some other variations, the electrodes (146, 148) are not arranged in pairs, such that each arm (140) has only one electrode array (146) or one electrode array (148).

[0045] The end effector (130) further includes a longitudinally spaced annular electrode array (132) at the distal end of the catheter shaft (122) proximal to the arm (140). The electrodes (132) can also be configured to cooperate in pairs to provide bipolar sensing of electrocardiogram signals when the electrodes (132) are placed in contact with cardiovascular tissue. Alternatively, one or more electrodes (132) can be used to provide unipolar sensing. In some other versions, one or all of the electrodes (132) are omitted.

[0046] The end effector (130) further includes a central shaft (150) that projects distally from the distal end (124) of the catheter shaft (122), proximate the proximal end of the arm (140). The central shaft (150) is coaxially aligned with the catheter shaft (122) and defines a distal opening (152) that communicates with a lumen formed along the length of the central shaft (150). The lumen is in fluid communication with the fluid conduit (40), which is further in fluid communication with the fluid source (42) as described above. Thus, the central shaft (150) is operable to dispense an irrigation fluid (e.g., saline) from the fluid source (42) to a location within the patient (PA) (e.g., within a cardiovascular structure) via the distal opening (152). In some other versions, the central shaft (150) lacks a distal opening (152) and is not otherwise capable of dispensing irrigation fluid.

[0047] The central shaft (150) of this example also includes a ring electrode (154) configured to serve as a reference electrode as will be described in more detail below. When the end effector (130) is located within a cardiovascular structure in the patient's body (e.g., in a pulmonary vein, etc.), the ring electrode (154) is positioned to contact blood. However, the arm (140) is also configured to prevent the ring electrode (154) from contacting tissue when the end effector (130) is positioned in the cardiovascular structure. Thus, during normal use, one or more electrodes (146, 148) will contact tissue, while the ring electrode (154) will not contact tissue. For example, Figure 4 As shown in , the physician (PH) can force the end effector (130) against the tissue surface (T). This can cause one or more arms (140) to generally flatten along the tissue surface (T), thereby placing the electrodes (146, 148) in direct contact with the tissue surface (T). However, the ring electrode (154) can be separated from the tissue surface (T) by the gap (G). Even if the physician continues to push the end effector (130) further distally toward the tissue surface (T), and even if the arms (140) are able to splay further outward, the distal end of the central shaft (150) will contact the tissue surface (T) before the ring electrode (154) contacts the tissue surface (T). Therefore, during normal use of the end effector (130), the ring electrode (154) will not contact the tissue surface (T).

[0048] Although the ring electrode (154) does not contact the tissue surface (T), the ring electrode (154) will still contact the blood flowing through the cardiovascular system. For example, if the end effector (130) is positioned in the pulmonary vein, one or more electrodes (146, 148) may contact the tissue surface (T), while the ring electrode (154) contacts the blood flowing through the pulmonary vein. The one or more electrodes (146, 148) contacting the tissue surface (T) may obtain a potential at the contact area of the tissue surface (T), while the ring electrode (154) obtains a reference potential from the blood in which the ring electrode (154) is disposed. The processor of the console (12) may process the potentials from the electrodes (146, 148, 154) to provide an electrocardiogram signal. Such an electrocardiogram signal can be used to provide EP mapping to identify the location of abnormal electrical activity within the cardiac anatomy. This, in turn, may allow the physician (PH) to identify the most appropriate areas of cardiac tissue to ablate (eg, with RF energy, cryoablation, etc.), thereby preventing or at least reducing the propagation of abnormal electrical activity across the cardiac tissue.

[0049] Figure 5 An exemplary three-dimensional profile (160) is shown that may be defined by at least a proximal portion of the arm (140). Figure 5160 . The arm (140) is omitted from the illustration, but it should be understood that at least the proximal portion of the arm (140) can be generally arranged around a boundary depicted as a three-dimensional profile (160). In some versions, the arm (140) is resiliently biased so that at least the proximal portion of the arm (140) defines the three-dimensional profile (160). The three-dimensional profile (160) of this example includes a cylindrical portion (162) and a flared frustoconical portion (170). The cylindrical portion (162) is bounded proximally by a proximal plane (166) and distally by a midplane (164). The proximal plane (166) is located at the distal end (124) of the catheter shaft (122). The flared frustoconical portion (170) is bounded proximally by the midplane (164) and distally by a distal plane (172).

[0050] In some versions, the distal plane (172) is located at the free ends or distal tips of the arms (140), such that the arms (140) terminate distally at the distal plane (172). In some other versions, the arms (140) continue to extend distally along respective linear paths at the distal plane (172), such that the flared frustoconical portion (170) represents an intermediate curved portion of each arm (140) that is longitudinally interposed between respective distal and proximal linear portions of each arm (140). In some versions in which the arms (140) extend distally along respective linear paths at the distal plane (172), these respective linear paths are oriented obliquely away from the longitudinal axis (LL) of the catheter shaft (122). Figure 7 An example of such a configuration is shown in , which depicts only one arm ( 140 ) of end effector ( 130 ), with it being understood that the other arms ( 140 ) may be similarly configured (albeit arranged in an angularly spaced array).

[0051] like Figure 7 As shown in FIG, the arm (140) includes a first segment (141), a second segment (143), and a third segment (145). The first segment (141) extends from the distal end (124) of the shaft (122), from the proximal plane (166) to the mid-plane (164). The first segment (141) is substantially straight and parallel to the central longitudinal axis (LL) of the shaft (122). Therefore, the first segment (141) of the angularly spaced array of arms (140) will generally define a cylindrical portion (162) of the three-dimensional profile (160), as described above in Figure 5The second segment (143) is distal to the first segment (141) and extends from the median plane (164) to the distal plane (172). The second segment (143) extends along a curve, curving away from the central longitudinal axis (LL) of the shaft (122). Thus, the second segment (143) of the angularly spaced array of arms (140) will generally define a flared frustoconical portion (170) of the three-dimensional profile (160), as described above in Figure 5 Alternatively, the second segment (143) may extend away from the central longitudinal axis (LL) of the shaft (122) along a respective straight path oriented obliquely relative to the central longitudinal axis (LL) of the shaft (122), thereby generally defining a pyramidal frustoconical portion (190) of the three-dimensional profile (180), as described above in Figure 6 The third section (145) is distal to the second section (143) and extends distally from the distal plane (172). The third section (145) extends along a straight path that is oriented obliquely relative to the central longitudinal axis (LL) of the shaft (122). In a configuration where the second section (143) is straight rather than curved, the oblique angle defined between the third section (145) and the central longitudinal axis (LL) of the shaft (122) may be greater than the oblique angle defined between the second section (143) and the central longitudinal axis (LL) of the shaft (122).

[0052] In some other configurations, the arms (140) extend distally along respective linear paths at the distal plane (172), which are parallel to the longitudinal axis (LL) of the catheter shaft (122). By way of example only, such configurations may generally resemble Figure 16 The end effector (1130) shown in and described below. In these versions, in a manner similar to Figure 7 In the version shown in , or in other configurations, it should be understood that arm (140) may continue to extend distally beyond distal plane (172) such that distal plane (172) should not be considered to necessarily correspond to the distal end of the end effector (130).

[0053] In this example, the median plane (164) represents a longitudinal position where the arms (140) transition from being generally straight and parallel to one another to flaring outwardly away from one another along corresponding curves. The cross-sectional area (Ap) of the proximal plane (166) region of the three-dimensional profile (160) is approximately equal to the cross-sectional area (Ai) of the median plane (164) region of the three-dimensional profile (160). The cross-sectional area (Ad) of the distal end plane (172) region is greater than the cross-sectional areas of the other planes (164, 166). Although the cross-sectional areas (Ap, Ai, Ad) are shown as being orthogonal to the longitudinal axis (LL) in the exemplary figures, since the configuration of the arms (140) is symmetrical about the longitudinal axis (LL), the flaring of the arms (140) does not necessarily have to be symmetrical about the longitudinal axis (LL), and thus the proximal, median, and distal planes of the respective areas (Ap, Ai, Ad) may intersect one another or otherwise be non-orthogonal to the longitudinal axis (LL).

[0054] In this example, the central shaft (150) and the ring electrode (154) are configured and positioned so that the longitudinal position of the electrode (154) corresponds to the cylindrical portion (162) of the three-dimensional profile (160). Thus, the ring electrode (154) is positioned proximally relative to the medial plane (164). Thus, the ring electrode (154) can be considered to be obscured by the cylindrical portion (162) of the three-dimensional profile (160) defined by the arm (140) of the end effector (130). In some other versions, the central shaft (150) and the ring electrode (154) are configured and positioned so that the ring electrode (154) is longitudinally positioned between the distal plane (172) and the medial plane (164). In this type of version, the ring electrode (154) can be considered to be obscured by the flared frustoconical portion (170) of the three-dimensional profile (160) defined by the arm (140) of the end effector (130).

[0055] By having the flared frustoconical portion (170) or cylindrical portion (162) of the three-dimensional profile (160) defined by the spine or arms (140) of the end effector (130) cover the ring electrode (154), blood flow around the ring electrode (154) can be relatively smooth, which can enable the ring electrode (154) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (140) around the ring electrode (154) can affect the blood flow around the electrode (154) so that the turbulence of the flow can be less than if the ring electrode (154) is positioned elsewhere; and the acquisition of a potential from the blood by the ring electrode (154) is more reliable than would be the case if the ring electrode (154) were positioned elsewhere. When the ring electrode (154) is covered by the cylindrical portion (164), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (154) can be particularly enhanced.

[0056] Figure 6 Another exemplary three-dimensional profile (180) is shown that may be defined by at least a proximal portion of the arm (140). Figure 6 1 . The arm (140) is omitted from the illustration, but it should be understood that at least the proximal portion of the arm (140) may generally be arranged around a boundary depicted as a three-dimensional profile (180). In some versions, the arm (140) is resiliently biased such that at least the proximal portion of the arm (140) defines the three-dimensional profile (180). The three-dimensional profile (180) of this example includes a cylindrical portion (162) and a pyramidal frustoconical portion (190). The cylindrical portion (162) is bounded proximally by a proximal plane (166) and distally by a midplane (164). The proximal plane (166) is located at the distal end (124) of the catheter shaft (122). The pyramidal frustoconical portion (190) is bounded proximally by the midplane (164) and distally by a distal plane (192).

[0057] In some versions, distal plane (192) is located at the free ends or distal tips of the arms (140), such that the arms (140) terminate distally at distal plane (192). In some other versions, the arms (140) continue to extend distally along respective linear paths at distal plane (192), such that the pyramidal frustoconical portion (190) represents an intermediate angled portion of each arm (140) that is longitudinally interposed between the respective distal portion and the proximal linear portion of each arm (140). In some versions in which the arms (140) extend distally along respective linear paths at distal plane (192), these respective linear paths are oriented obliquely away from the longitudinal axis (LL) of the catheter shaft (122) (e.g., at an angle greater than the angle represented by the pyramidal frustoconical portion (190)). In some other versions, the arms (140) extend distally along respective linear paths at the distal planes (192), which are parallel to the longitudinal axis (LL) of the catheter shaft (122). In either case, or in other configurations, it should be understood that the arms (140) may continue to extend distally beyond the distal planes (192), such that the distal planes (192) should not be considered to necessarily correspond to the distal end of the end effector (130).

[0058] In this example, the mid-plane (164) represents the longitudinal position in which the arms (140) transition from being generally straight and parallel to one another to flaring outwardly away from one another along corresponding oblique paths. The cross-sectional area of the proximal plane (166) of the three-dimensional profile (180) is approximately equal to the cross-sectional area of the mid-plane (164) of the three-dimensional profile (180). The cross-sectional area of the distal end plane (192) is greater than the cross-sectional areas of the other planes (164, 166).

[0059] In this example, the central shaft (150) and the ring electrode (154) are configured and positioned so that the longitudinal position of the electrode (154) corresponds to the cylindrical portion (162) of the three-dimensional profile (180). Thus, the ring electrode (154) is positioned proximally relative to the median plane (164). Thus, the ring electrode (154) can be considered to be obscured by the cylindrical portion (162) of the three-dimensional profile (180) defined by the arm (140) of the end effector (130). In some other versions, the central shaft (150) and the ring electrode (154) are configured and positioned so that the ring electrode (154) is longitudinally positioned between the distal plane (192) and the median plane (164). In this type of version, the ring electrode (154) can be considered to be obscured by the pyramidal frustoconical portion (190) of the three-dimensional profile (180) defined by the arm (140) of the end effector (130).

[0060] By having the pyramidal frustoconical portion (190) or cylindrical portion (162) of the three-dimensional profile (190) defined by the arms (140) of the end effector (130) cover the ring electrode (154), blood flow around the ring electrode (154) can be relatively smooth, which can enable the ring electrode (154) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (140) around the ring electrode (154) can affect the blood flow around the electrode (154) so that the turbulence of the flow can be less than if the ring electrode (154) is positioned elsewhere; and the acquisition of a potential from the blood by the ring electrode (154) is more reliable than would be the case if the ring electrode (154) was positioned elsewhere. When the ring electrode (154) is covered by the cylindrical portion (162), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (154) can be particularly enhanced.

[0061] C. Example Basket End Effector with Reference Electrode on Inner Shaft

[0062] Figure 8Another exemplary end effector (200) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (200) of this example includes an extendable assembly (220) formed by an array of angularly spaced beams (222). Each beam (222) includes four pairs (230) of bipolar electrodes (232, 234). Each of the electrodes (232, 234) is generally rectangular and configured to acquire an electrical potential from tissue, just like the electrodes (146, 148) described above. The electrodes (232, 234) can be used in a bipolar or monopolar manner. In this example, the entirety of each electrode (232, 234) is confined to the outwardly present surface of each beam (222). Thus, the beam (222) has electrodes (232, 234) only on one side of each beam (222) (i.e., the tissue-contacting side of each beam (222)).

[0063] The proximal end of the beam (222) is positioned in the outer shaft (210), which can be considered similar to the catheter shaft (122) described above. The distal end of the beam (222) is coupled to the hub member (212). The hub member (212) is fixed to the central inner shaft (250), which is coaxially positioned at the center of the extendable assembly (220). The beam (222) is configured to transition the extendable assembly (220) between a non-extended state and an extended state. The extended state is Figure 8 . When the extendable assembly (220) is in the non-extended state, the beams (222) are urged inwardly to define an effective outer diameter that is less than or equal to the inner diameter of the outer shaft (210). In some versions, the beams (222) are resiliently biased to provide the extendable assembly (220) in the extended state. In some such versions, the outer sheath (214) is slidably disposed about the outer shaft (210). When the sheath (214) is in a distal position (e.g., such that the distal end of the sheath (214) is distal to the hub member (212)), the sheath (214) constrains the beams (222) inwardly, thereby maintaining the extendable assembly (220) in the non-extended state. When the sheath (214) is in a proximal position (e.g., such as Figure 8 As shown in FIG, beams (222) can elastically provide extendable assembly (220) in an extended state when the distal end of sheath (214) is proximal to extendable assembly (220).

[0064] As another merely illustrative alternative, the state of the extendable assembly (220) may be based on the relative longitudinal positioning of the inner shaft (250) and the outer shaft (210). In a configuration where the inner shaft (250) is longitudinally stationary relative to the handle (110), an actuator on the handle (110) may drive the outer shaft (210) proximally relative to the inner shaft (250) to urge the extendable assembly (220) toward the non-extended state, and drive the outer shaft (210) distally relative to the inner shaft (250) to urge the extendable assembly (220) toward the extended state. In a configuration in which the outer shaft (210) is longitudinally stationary relative to the handle (110), an actuator on the handle (110) can drive the inner shaft (250) distally relative to the outer shaft (210) to urge the extendable assembly (220) toward the extended state, and can drive the inner shaft (250) proximally relative to the inner shaft (210) to urge the extendable assembly (220) toward the extended state. Various suitable forms of input that can be provided on the handle (110) to provide such actuation, as well as various suitable ways in which the extendable assembly (220) can transition between the non-extended state and the extended state, will be apparent to those skilled in the art in view of the teachings herein.

[0065] like Figure 8 As shown in , the configuration of the end effector (200) can be considered to be related to three planes (264, 266, 272) that are perpendicular to the longitudinal axis (LL) of the shaft (210, 250). The proximal plane (266) is located at the distal end of the shaft (210) and is located at the proximal end of the end effector (200). The middle plane (264) is distal to the proximal plane (266). The distal plane (272) is distal to the middle plane (264). The longitudinal region of the end effector (200) between the planes (264, 266) can be considered to be a cylindrical portion (262) that defines a cylindrical three-dimensional profile, very similar to the above description of Figure 5-6 The cylindrical portion (162) described above. Thus, the portion of the beam (222) extending along the cylindrical portion (262) can extend along a corresponding straight path parallel to the longitudinal axis (LL) of the shaft (210, 250). The longitudinal region of the end effector (200) between the planes (264, 272) can be considered to be a flared frustoconical portion (270) that defines a flared frustoconical three-dimensional profile, very similar to the above description of Figure 5The flared frustoconical portion. In this example, the portion of the beam (222) extending along the flared frustoconical portion (270) extends along a corresponding curved path that curves outwardly away from the longitudinal axis (LL) of the shaft (210, 250). The portion of the beam (222) extending distally from the distal plane (272) curves inwardly back toward the longitudinal axis (LL) of the shaft (210, 250) and ultimately leads to the hub member (212). Thus, the distal plane (272) represents the transition portion of the beam (222) extending outwardly along the corresponding curved path to extending inwardly along the corresponding curved path.

[0066] The inner shaft (250) of this example includes an annular electrode (254) coaxially disposed around the inner shaft (250), such as Figure 9 In this example, the ring electrode (254) is longitudinally positioned between the planes (264, 266) such that the longitudinal position of the ring electrode (254) corresponds to the longitudinal position of the cylindrical portion (262), and such that the ring electrode (254) is concealed by the cylindrical portion (262). In some other versions, the ring electrode (254) is longitudinally positioned between the planes (264, 272) such that the longitudinal position of the ring electrode (254) corresponds to the longitudinal position of the flared frustoconical portion (270), and such that the ring electrode (254) is concealed by the flared frustoconical portion (270).

[0067] Thus, the beam (222) is configured to prevent tissue from contacting the ring electrode (254). However, the beam (222) allows blood to flow through the extendable assembly (220), thereby allowing blood to contact the ring electrode (254). During use of the end effector (200), one or more electrodes (232, 234) on the beam (222) can contact the tissue surface (T) and thereby acquire a potential at the contact area of the tissue surface (T), while the ring electrode (254) acquires a reference potential from the blood in which the ring electrode (254) is disposed. A processor of the console (12) can process the potentials from the electrodes (232, 234, 254) and thereby provide an electrocardiogram signal as described above.

[0068] By having the flared frustoconical portion (190) or cylindrical portion (262) of the three-dimensional profile defined by the beam (222) of the end effector (200) cover the ring electrode (254), blood flow around the ring electrode (254) can be relatively smooth, which can enable the ring electrode (254) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the beam (222) around the ring electrode (254) can affect the blood flow around the electrode (254) so that the turbulence of the flow can be less than if the ring electrode (254) is positioned elsewhere; and the acquisition of a potential from the blood by the ring electrode (254) is more reliable than would be the case if the ring electrode (254) was positioned elsewhere. When the ring electrode (254) is covered by the cylindrical portion (262), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (254) can be particularly enhanced.

[0069] D. Exemplary Multi-Arm End Effector with Integral Reference Electrode

[0070] Figure 10 Another exemplary end effector (530) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (530) of this example includes an outer arm (540) and an outer arm (544). The arms (540, 544) extend distally from the distal end (524) of the catheter shaft (522). The arm (540) defines an outer ring, while the arm (544) defines an inner ring. The outer ring and the inner ring are coupled to each other by an elastic connecting member (546) at the distal end of each ring. The longitudinal middle regions of the arms (540, 544) are parallel to each other. The proximal ends of the arms (540, 544) converge at the distal end (524) of the catheter shaft (522).

[0071] In this example, the arms (540, 544) are positioned along a single, flat plane. However, the arms (540, 544) are also flexible such that the arms (540, 544) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by the arms (540, 544), thereby deforming the plane defined by the arms (540, 544). Such bending can occur when the end effector (530) is pressed laterally against tissue. The arms (540, 544) can be resiliently biased to return to Figure 10 In some other versions, portions of arms (540, 544) are further offset from one another such that arms (540, 544) do not lie along a single, planar plane.

[0072] The proximal ends of the arms (540, 544) extend along corresponding linear paths between the proximal plane (566) and the mid-plane (564), the linear paths being generally parallel to each other and generally parallel to the longitudinal axis (LL) of the catheter shaft (522). The proximal regions of the arms (540, 544) between the planes (564, 566) together define a first, generally rectangular portion (562) of the profile of the end effector (530). Distal to the first portion (562), the arms (540, 544) define a diverging second portion (570) of the profile of the end effector (530). The second portion (570) extends from the mid-plane (564) to the distal plane (572). The arms (540, 544) thus extend outwardly through the second portion (570) along corresponding diverging paths. As described above, distal to the distal plane (572), the arms (540, 544) extend along corresponding linear paths that are parallel to each other.

[0073] Each arm (540, 544) has an array of longitudinally spaced electrodes (542). Each electrode (542) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, the electrodes (542) are arranged in pairs, such as the electrodes (146, 148) described above.

[0074] End effector (530) further includes a central inner shaft (550) having a ring electrode (554). Ring electrode (554) is coaxially disposed about inner shaft (550). In the present example, ring electrode (554) is longitudinally positioned between planes (564, 572) such that the longitudinal position of ring electrode (554) corresponds to the longitudinal position of second portion (570) and such that ring electrode (554) is concealed by second portion (570). In some other versions, ring electrode (554) is longitudinally positioned between planes (564, 566) such that the longitudinal position of ring electrode (554) corresponds to the longitudinal position of first portion (562) and such that ring electrode (554) is concealed by first portion (562).

[0075] In the case where the ring electrode (554) is covered by the first portion (562) or the second portion (570), the arms (540, 544) generally prevent tissue from contacting the ring electrode (554). However, the arms (540, 544) allow blood to flow through the end effector (530), thereby allowing blood to contact the ring electrode (554). During use of the end effector (530), one or more electrodes (542) on the arms (540, 544) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (554) obtains a reference potential from the blood in which the ring electrode (554) is disposed. The processor of the console (12) can process the potentials from the electrodes (542, 554) to provide an electrocardiogram signal as described above.

[0076] By having the first portion (562) or the second portion (570) of the contour defined by the arms (540, 544) of the end effector (530) cover the ring electrode (554), blood flow around the ring electrode (554) can be relatively smooth, which can enable the ring electrode (554) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (540, 544) around the ring electrode (554) can affect the blood flow around the electrode (554) so that the turbulence of the flow can be less than if the ring electrode (554) were positioned elsewhere; and the acquisition of a potential from the blood by the ring electrode (554) is more reliable than would be the case if the ring electrode (554) were positioned elsewhere. When the ring electrode (554) is covered by the first portion (562), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (554) can be particularly enhanced.

[0077] Figure 11Another exemplary end effector (630) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (630) of this example includes a pair of outer arms (640) and a pair of inner arms (644). The arms (640, 644) extend distally from the distal end (624) of the catheter shaft (622) and the distal ends terminate at a joint (646). In some versions, the joint (646) is formed simply by welding, adhering, or otherwise fixing the distal ends of the arms (640, 644) together. The longitudinal mid-regions of the arms (640, 644) are parallel to each other. The proximal ends of the arms (640, 644) converge at the distal end (624) of the catheter shaft (622), while the distal ends of the arms (640, 644) typically converge at the joint (646). In this example, the arms (640, 644) are both positioned along a single, flat plane. However, the arms (640, 644) are also flexible such that the arms (640, 644) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by the arms (640, 644), thereby deforming the plane defined by the arms (640, 644). Such bending can occur when the end effector (630) is pressed laterally against tissue. The arms (640, 644) can be resiliently biased to return to Figure 11 In some other versions, portions of arms ( 640 , 644 ) are further offset from one another such that arms ( 640 , 644 ) do not lie along a single, planar plane.

[0078] The proximal ends of the arms (640, 644) extend along corresponding linear paths between the proximal plane (666) and the mid-plane (664), the linear paths being generally parallel to each other and generally parallel to the longitudinal axis (LL) of the catheter shaft (622). The proximal regions of the arms (640, 644) between the planes (664, 666) together define a first, generally rectangular portion (662) of the profile of the end effector (630). Distal to the first portion (662), the arms (640, 644) define a diverging second portion (670) of the profile of the end effector (630). The second portion (670) extends from the mid-plane (664) to the distal plane (672). The arms (640, 644) thus extend outwardly through the second portion (670) along corresponding diverging paths. As described above, distal to the distal plane (672), the arms (640, 644) extend along corresponding linear paths that are parallel to each other.

[0079] Each arm (640, 644) has an array of longitudinally spaced electrodes (642). Each electrode (642) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, the electrodes (642) are arranged in pairs, such as the electrodes (146, 148) described above.

[0080] End effector (630) further includes a central inner shaft (650) having a ring electrode (654). Ring electrode (654) is coaxially disposed about inner shaft (650). In the present example, ring electrode (654) is longitudinally positioned between planes (664, 672) such that the longitudinal position of ring electrode (654) corresponds to the longitudinal position of second portion (670) and such that ring electrode (654) is obscured by second portion (670). In some other versions, ring electrode (654) is longitudinally positioned between planes (664, 666) such that the longitudinal position of ring electrode (654) corresponds to the longitudinal position of first portion (662) and such that ring electrode (654) is obscured by first portion (662).

[0081] In the case where the ring electrode (654) is covered by the first portion (662) or the second portion (670), the arms (640, 644) generally prevent tissue from contacting the ring electrode (654). However, the arms (640, 644) allow blood to flow through the end effector (630), thereby allowing blood to contact the ring electrode (654). During use of the end effector (630), one or more electrodes (642) on the arms (640, 644) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (654) obtains a reference potential from the blood in which the ring electrode (654) is disposed. The processor of the console (12) can process the potentials from the electrodes (642, 654) to provide an electrocardiogram signal as described above.

[0082] By having the first portion (662) or the second portion (670) of the contour defined by the arms (640, 644) of the end effector (630) cover the ring electrode (654), blood flow around the ring electrode (654) can be relatively smooth, which can enable the ring electrode (654) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (640, 644) around the ring electrode (654) can affect the blood flow around the electrode (654) so that the flow is less turbulent than if the ring electrode (654) were positioned elsewhere; and the acquisition of a potential from the blood by the ring electrode (654) is more reliable than would be the case if the ring electrode (654) were positioned elsewhere. When the ring electrode (654) is covered by the first portion (662), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (654) can be particularly enhanced.

[0083] Figure 12Another exemplary end effector (730) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (730) of this example includes a pair of outer arms (740) and a pair of inner arms (744). The arms (740, 744) extend distally from the distal end (724) of the catheter shaft (722). The arm (740) terminates distally at a joint (746); while the arm (744) terminates distally at a joint (752) proximal to the joint (746). In some versions, each joint (746, 752) is formed simply by welding, adhering, or otherwise fixing the distal ends of the corresponding arms (740, 744) together. The longitudinal mid-regions of the arms (740, 744) are generally parallel to each other. The proximal ends of the arms (740, 744) converge at the distal end (724) of the catheter shaft (722), while the distal ends of the arms (740, 744) converge at respective joints (746, 752). In this example, the arms (740, 744) are both positioned along a single, flat plane. However, the arms (740, 744) are also flexible such that the arms (740, 744) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by the arms (740, 744), thereby deforming the plane defined by the arms (740, 744). Such bending can occur when the end effector (730) is pressed laterally against tissue. The arms (740, 744) can be elastically biased to return to Figure 12 In some other versions, portions of arms (740, 744) are further offset from one another such that arms (740, 744) do not lie along a single, flat plane.

[0084] The proximal ends of the arms (740, 744) extend along corresponding linear paths between the proximal plane (766) and the mid-plane (764), the linear paths being generally parallel to each other and generally parallel to the longitudinal axis (LL) of the catheter shaft (722). The proximal regions of the arms (740, 744) between the planes (764, 766) together define a first, generally rectangular portion (762) of the profile of the end effector (730). Distal to the first portion (762), the arms (740, 744) define a diverging second portion (770) of the profile of the end effector (730). The second portion (770) extends from the mid-plane (764) to the distal plane (772). The arms (740, 744) thus extend outwardly through the second portion (770) along corresponding diverging paths. As described above, distal to the distal plane (772), the arms (740, 744) extend along corresponding linear paths that are parallel to each other.

[0085] Each arm (740, 744) has an array of longitudinally spaced electrodes (742). Each electrode (742) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, the electrodes (742) are arranged in pairs, such as the electrodes (146, 148) described above.

[0086] End effector (730) further includes a central inner shaft (750) having a ring electrode (754). Ring electrode (754) is coaxially disposed about inner shaft (750). In the present example, ring electrode (754) is longitudinally positioned between planes (764, 772) such that the longitudinal position of ring electrode (754) corresponds to the longitudinal position of second portion (770) and such that ring electrode (754) is concealed by second portion (770). In some other versions, ring electrode (754) is longitudinally positioned between planes (764, 766) such that the longitudinal position of ring electrode (754) corresponds to the longitudinal position of first portion (762) and such that ring electrode (754) is concealed by first portion (762).

[0087] In the case where the ring electrode (754) is covered by the first portion (762) or the second portion (770), the arms (740, 744) generally prevent tissue from contacting the ring electrode (754). However, the arms (740, 744) allow blood to flow through the end effector (730), thereby allowing blood to contact the ring electrode (754). During use of the end effector (730), one or more electrodes (742) on the arms (740, 744) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (754) obtains a reference potential from the blood in which the ring electrode (754) is disposed. The processor of the console (12) can process the potentials from the electrodes (742, 754) to provide an electrocardiogram signal as described above.

[0088] By having the first portion (762) or the second portion (770) of the contour defined by the arms (740, 744) of the end effector (730) cover the ring electrode (754), blood flow around the ring electrode (754) can be relatively smooth, which can enable the ring electrode (754) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (740, 744) around the ring electrode (754) can affect the blood flow around the electrode (754) so that the turbulence of the flow can be less than if the ring electrode (754) is positioned elsewhere; and the acquisition of a potential from the blood by the ring electrode (754) is more reliable than would be the case if the ring electrode (754) were positioned elsewhere. When the ring electrode (754) is covered by the first portion (762), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (754) can be particularly enhanced.

[0089] Figure 13 Another exemplary end effector (830) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (830) of this example includes an outer arm (840) and an inner arm (844). The arms (840, 844) extend distally from the distal end (824) of the catheter shaft (822). The arm (840) forms a distal bend (846); and the arm (844) forms a distal bend (852) proximal to the distal bend (846). The longitudinal mid-regions of the arms (840, 844) are generally parallel to each other. The proximal ends of the arms (840, 844) converge at the distal end (824) of the catheter shaft (822). In this example, the arms (840, 844) are positioned along a single flat plane. However, the arms (840, 844) are also flexible such that the arms (840, 844) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by the arms (840, 844), thereby deforming the plane defined by the arms (840, 844). Such bending can occur when the end effector (830) is pressed laterally against tissue. The arms (840, 844) can be resiliently biased to return to Figure 13 In some other versions, portions of arms (840, 844) are further offset from one another such that arms (840, 844) do not lie along a single, flat plane.

[0090] The proximal ends of the arms (840, 844) extend along corresponding linear paths between the proximal plane (866) and the mid-plane (864), the linear paths being generally parallel to each other and generally parallel to the longitudinal axis (LL) of the catheter shaft (822). The proximal regions of the arms (840, 844) between the planes (864, 866) together define a first, generally rectangular portion (862) of the profile of the end effector (830). Distal to the first portion (862), the arms (840, 844) define a second, diverging portion (870) of the profile of the end effector (830). The second portion (870) extends from the mid-plane (864) to the distal plane (872). The arms (840, 844) thus extend outwardly through the second portion (870) along corresponding diverging paths. As described above, distal to the distal plane (872), the arms (840, 844) extend along corresponding linear paths that are parallel to each other.

[0091] Each arm (840, 844) has an array of longitudinally spaced electrodes (842). Each electrode (842) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, the electrodes (842) are arranged in pairs, such as the electrodes (146, 148) described above.

[0092] End effector (830) further includes a central inner shaft (850) having a ring electrode (854). Ring electrode (854) is coaxially disposed about inner shaft (850). In the present example, ring electrode (854) is longitudinally positioned between planes (864, 872) such that the longitudinal position of ring electrode (854) corresponds to the longitudinal position of second portion (870), and such that ring electrode (854) is obscured by second portion (870). In some other versions, ring electrode (854) is longitudinally positioned between planes (864, 866) such that the longitudinal position of ring electrode (854) corresponds to the longitudinal position of first portion (862), and such that ring electrode (854) is obscured by first portion (862).

[0093] In the case where the ring electrode (854) is covered by the first portion (862) or the second portion (870), the arms (840, 844) generally prevent tissue from contacting the ring electrode (854). However, the arms (840, 844) allow blood to flow through the end effector (830), thereby allowing blood to contact the ring electrode (854). During use of the end effector (830), one or more electrodes (842) on the arms (840, 844) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (854) obtains a reference potential from the blood in which the ring electrode (854) is disposed. The processor of the console (12) can process the potentials from the electrodes (842, 854) to provide an electrocardiogram signal as described above.

[0094] By having the first portion (862) or the second portion (870) of the contour defined by the arms (840, 844) of the end effector (830) cover the ring electrode (854), blood flow around the ring electrode (854) can be relatively smooth, which can enable the ring electrode (854) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (840, 844) around the ring electrode (854) can affect the blood flow around the electrode (854) so that the flow is less turbulent than if the ring electrode (854) were positioned elsewhere, and the acquisition of a potential from the blood by the ring electrode (854) is more reliable than would be the case if the ring electrode (854) were positioned elsewhere. When the ring electrode (854) is covered by the first portion (862), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (854) can be particularly enhanced.

[0095] Figure 14Another exemplary end effector (930) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (930) of this example includes a first arm (940) and a second arm (944). The arms (940, 944) extend distally from the distal end (924) of the catheter shaft (922). Each arm (940) forms a corresponding distal bend (946), which is located at the same longitudinal distance as the distal end (924) of the catheter shaft (922). The arms (940, 944) overlap each other at an overlap point (980). The longitudinal mid-regions (940, 944) of the arms are generally parallel to each other. The proximal ends of the arms (940, 944) converge at the distal end (924) of the catheter shaft (922). In this example, the arms (940) are positioned along a first flat plane. In this example, arms (944) are positioned along a second, planar plane that is slightly offset from the first plane of arms (940). Arms (940, 944) are also flexible such that arms (940, 944) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by arms (940, 944), thereby deforming the plane defined by arms (940, 944). Such bending can occur when end effector (930) is pressed laterally against tissue. Arms (940, 944) can be resiliently biased to return to Figure 14 In some other versions, portions of arms (940, 944) are further offset from one another such that arms (940, 944) do not lie along a single, planar plane.

[0096] The proximal ends of the arms (940, 944) extend along respective linear paths between the proximal plane (966) and the mid-plane (964), the linear paths being generally parallel to each other and generally parallel to the longitudinal axis (LL) of the catheter shaft (922). The proximal regions of the arms (840, 844) between the planes (940, 944) together define a generally rectangular first portion (962) of the profile of the end effector (930). Distal to the first portion (962), the arms (940, 944) define a diverging second portion (970) of the profile of the end effector (930). The second portion (970) extends from the mid-plane (964) to the distal plane (972). The arms (940, 944) thus extend outwardly through the second portion (970) along respective diverging paths. As described above, distal to the distal plane (972), the arms (940, 944) extend along respective linear paths that are parallel to each other.

[0097] Each arm (940, 944) has an array of longitudinally spaced electrodes (942). Each electrode (942) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, the electrodes (942) are arranged in pairs, such as the electrodes (146, 148) described above.

[0098] End effector (930) further includes a central inner shaft (950) having a ring electrode (954). Ring electrode (954) is coaxially disposed about inner shaft (950). In the present example, ring electrode (954) is longitudinally positioned between planes (964, 972) such that the longitudinal position of ring electrode (954) corresponds to the longitudinal position of second portion (970) and such that ring electrode (954) is concealed by second portion (970). In some other versions, ring electrode (954) is longitudinally positioned between planes (964, 966) such that the longitudinal position of ring electrode (954) corresponds to the longitudinal position of first portion (962) and such that ring electrode (954) is concealed by first portion (962).

[0099] In the case where the ring electrode (954) is covered by the first portion (962) or the second portion (970), the arms (940, 944) generally prevent tissue from contacting the ring electrode (954). However, the arms (940, 944) allow blood to flow through the end effector (930), thereby allowing blood to contact the ring electrode (954). During use of the end effector (930), one or more electrodes (942) on the arms (940, 944) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (954) obtains a reference potential from the blood in which the ring electrode (954) is disposed. The processor of the console (12) can process the potentials from the electrodes (942, 954) to provide an electrocardiogram signal as described above.

[0100] By having the first portion (962) or the second portion (970) of the contour defined by the arms (940, 944) of the end effector (930) cover the ring electrode (954), blood flow around the ring electrode (954) can be relatively smooth, which can enable the ring electrode (954) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (940, 944) around the ring electrode (954) can affect the blood flow around the electrode (954) so that the flow is less turbulent than if the ring electrode (954) were positioned elsewhere, and the acquisition of a potential from the blood by the ring electrode (954) is more reliable than would be the case if the ring electrode (954) were positioned elsewhere. When the ring electrode (954) is covered by the first portion (962), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (954) can be particularly enhanced.

[0101] Figure 15 Another exemplary end effector (1030) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (1030) of this example includes a first arm (1040), a second arm (1044), and a third arm (1046). The arms (1040, 1044, 1046) extend distally from the distal end (1024) of the catheter shaft (1022). Each arm (1040) forms a corresponding distal bend (1046), which is located at the same longitudinal distance as the distal end (1024) of the catheter shaft (1022). The arms (1040, 1044) overlap each other at an overlap point (1080). The arms (1040, 1046) overlap each other at an overlap point (1084). The arms (1044, 1046) overlap each other at an overlap point (1082). The longitudinal mid-regions of the arms (1040, 1044, 1046) are generally parallel to each other. The proximal ends of the arms (1040, 1044, 1046) converge at the distal end (1024) of the catheter shaft (1022). In this example, the arm (1040) is positioned along a first flat plane. In this example, the arm (1044) is positioned along a second flat plane slightly offset from the first plane of the arm (1040). In this example, the arm (1046) is positioned along a third flat plane slightly offset from the first and second planes of the arms (1040, 1044).

[0102] The arms (1040, 1044, 1046) are also flexible such that the arms (1040, 1044, 1046) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by the arms (1040, 1044, 1046), thereby deforming the plane defined by the arms (1040, 1044, 1046). Such bending can occur when the end effector (1030) is pressed laterally against tissue. The arms (1040, 1044, 1046) can be resiliently biased to return to Figure 15 In some other versions, arm portions (1040, 1044, 1046) are further offset from one another such that arms (1040, 1044, 1046) do not lie along a single, flat plane.

[0103] The proximal ends of the arms (1040, 1044, 1046) extend along respective linear paths between a proximal plane (1066) and a mid-plane (1064), the linear paths being generally parallel to each other and generally parallel to the longitudinal axis (LL) of the catheter shaft (1022). The proximal-most regions of the arms (1040, 1044, 1046) between the planes (1064, 1066) together define a generally rectangular first portion (1062) of the profile of the end effector (1030). Distal to the first portion (1062), the arms (1040, 1044, 1046) define a diverging second portion (1070) of the profile of the end effector (1030). The second portion (1070) extends from the mid-plane (1064) to the distal plane (1072). Arms (1040, 1044, 1046) thus extend outwardly through second portion (1070) along respective diverging paths.As described above, distally of distal plane (1072), arms (1040, 1044, 1046) extend along respective linear paths that are parallel to one another.

[0104] Each arm (1040, 1044, 1046) has an array of longitudinally spaced electrodes (1042). Each electrode (1042) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, electrodes (1042) are provided in pairs, such as electrodes (146, 148) described above.

[0105] End effector (1030) further includes a central inner shaft (1050) having a ring electrode (1054). Ring electrode (1054) is coaxially disposed about inner shaft (1050). In the present example, ring electrode (1054) is longitudinally positioned between planes (1064, 1072) such that the longitudinal position of ring electrode (1054) corresponds to the longitudinal position of second portion (1070), and such that ring electrode (1054) is concealed by second portion (1070). In some other versions, ring electrode (1054) is longitudinally positioned between planes (1064, 1066) such that the longitudinal position of ring electrode (1054) corresponds to the longitudinal position of first portion (1062), and such that ring electrode (1054) is concealed by first portion (1062).

[0106] In the case where the ring electrode (1054) is covered by the first portion (1062) or the second portion (1070), the arms (1040, 1044, 1046) generally prevent tissue from contacting the ring electrode (1054). However, the arms (1040, 1044, 1046) allow blood to flow through the end effector (1030), thereby allowing blood to contact the ring electrode (1054). During use of the end effector (1030), one or more electrodes (1042) on the arms (1040, 1044, 1046) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (1054) obtains a reference potential from the blood in which the ring electrode (1054) is disposed. The processor of the console (12) can process the potentials from the electrodes (1042, 1054) to provide an electrocardiogram signal as described above.

[0107] By having the first portion (1062) or the second portion (1070) of the contour defined by the arms (1040, 1044, 1046) of the end effector (1030) cover the ring electrode (1054), blood flow around the ring electrode (1054) can be relatively smooth, which can enable the ring electrode (1054) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (1040, 1044, 1046) around the ring electrode (1054) can affect the blood flow around the electrode (1054) so that the flow is less turbulent than if the ring electrode (1054) were positioned elsewhere, and the acquisition of a potential from the blood by the ring electrode (1054) is more reliable than would be the case if the ring electrode (1054) were positioned elsewhere. The reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (1054) can be particularly enhanced when the ring electrode (1054) is covered by the first portion (1062).

[0108] Figure 16Another exemplary end effector (1130) that can be incorporated into a catheter assembly (100) in place of the end effector (130) is shown. The end effector (1130) of this example includes a pair of outer arms (1140) and a pair of outer arms (1144). The arms (1140, 1444) extend distally from the distal end (1124) of the catheter shaft (1122). Each arm (1140) terminates distally at a free end (1146). The longitudinal middle and distal regions of the arms (1140, 1444) are generally parallel to each other. The proximal ends of the arms (1140, 1444) converge at the distal end (1124) of the catheter shaft (1122). In this example, the arms (1140, 1444) are positioned along a single flat plane. However, the arms (1140, 1444) are also flexible such that the arms (1140, 1444) can bend laterally away from the central longitudinal axis (LL) along a path transverse to the plane defined by the arms (1140, 1444), thereby deforming the plane defined by the arms (1140, 1444). Such bending can occur when the end effector (1130) is pressed laterally against tissue. The arms (1140, 1444) can be resiliently biased to return to Figure 16 In some other versions, arm portions ( 1140 , 1444 ) are further offset from one another such that arms ( 1140 , 1444 ) do not lie along a single, flat plane.

[0109] The proximal ends of the arms (1140, 1444) extend between the proximal plane (1164) and the distal plane (1172) along respective paths that diverge outwardly away from each other and away from the longitudinal axis (LL) of the catheter shaft (1122). The proximal-most regions of the arms (1140, 1444) between the planes (1164, 1172) thus collectively define a diverging portion (1170) of the profile of the end effector (1130). As described above, distal to the distal plane (1172), the arms (1140, 1444) extend along respective straight paths that are parallel to each other.

[0110] Each arm (1140, 1444) has an array of longitudinally spaced electrodes (1142). Each electrode (1142) is configured to contact tissue and thereby acquire an electrical potential from the contacted tissue. In some versions, the electrodes (1142) are arranged in pairs, such as the electrodes (146, 148) described above.

[0111] End effector (1130) further includes a central inner shaft (1150) having a ring electrode (1154). Ring electrode (1154) is coaxially disposed about inner shaft (1150). In this example, ring electrode (1154) is longitudinally positioned between planes (1164, 1172) such that the longitudinal position of ring electrode (1154) corresponds to the longitudinal position of diverging portion (1170) and such that ring electrode (1154) is concealed by diverging portion (1170).

[0112] In the case where the ring electrode (1154) is covered by the diverging portion (1170), the arms (1140, 1444) generally prevent tissue from contacting the ring electrode (1154). However, the arms (1140, 1444) allow blood to flow through the end effector (1130), thereby allowing blood to contact the ring electrode (1154). During use of the end effector (1130), one or more electrodes (1142) on the arms (1140, 1444) can contact the tissue surface (T), thereby obtaining the potential at the contact area of the tissue surface (T), while the ring electrode (1154) obtains a reference potential from the blood in which the ring electrode (1154) is disposed. The processor of the console (12) can process the potentials from the electrodes (1142, 1154) to provide an electrocardiogram signal as described above.

[0113] By having the diverging portion (1170) of the outline defined by the arms (1140, 1444) of the end effector (1130) cover the ring electrode (1154), blood flow around the ring electrode (1154) can be relatively smooth, which can enable the ring electrode (1154) to acquire a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (1140, 1444) around the ring electrode (1154) can affect the blood flow around the electrode (1154) so that the flow is less turbulent than if the ring electrode (1154) were positioned elsewhere, and the acquisition of a potential from the blood by the ring electrode (1154) is more reliable than would be the case if the ring electrode (1154) were positioned elsewhere. When the ring electrode (1154) is covered by the diverging portion (1170), the reduction in blood flow turbulence and the increase in sensing reliability of the ring electrode (1154) can be particularly enhanced.

[0114] By way of further example only, in addition to having the features and functionality described above, any of the foregoing end effectors (130, 200, 530, 630, 530, 730, 830, 930, 1030, 1130) may be constructed and operated in accordance with at least some of the teachings of: U.S. Publication 2016 / 0374753, published on December 29, 2016, entitled “Catheter Having Closed Loop Array with In-Plane Linear Electrode Portion,” the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0056038, published on March 1, 2018, entitled “Catheter with Bipole Electrode Spacer and Related Methods,” the disclosure of which is incorporated herein by reference; and U.S. Publication 2018 / 0056038, published on March 6, 2018, entitled “Catheter Spine Assembly with U.S. Patent 9,907,480, entitled “Closely-Spaced Bipole Microelectrodes,” the disclosure of which is incorporated herein by reference; U.S. Patent 9,949,656, entitled “Catheter with Stacked Spine Electrode Assembly,” issued on April 24, 2018, the disclosure of which is incorporated herein by reference; or U.S. Patent 9,820,664, entitled “Catheter with High Density Electrode Spine Array,” issued on November 21, 2017, the disclosure of which is incorporated herein by reference.

[0115] E. Exemplary Irrigated Ablation Tip End Effector with Integral Reference Electrode

[0116] Figure 17 An enlarged perspective view of an end effector (1230) having a tip (1240) that can be incorporated into a catheter assembly (100) is shown. By way of further example only, an end effector (1230) can be provided in lieu of a Figure 3-6 The central axis (150) of the example shown in FIG, or instead of Figure 10-16The example shown in FIG. 1 shows a central inner shaft (550, 650, 750, 850, 950, 1050, 1150) of the catheter shaft (1222). The end effector (1230) of this example includes an irrigation tip (1240) positioned at the distal end (1224) of the catheter shaft (1222). The irrigation tip (1240) defines a hollow interior space and includes a main opening (1242) positioned adjacent to the end (1252) of the irrigation tip (1240). The main opening (1242) is provided with an irrigation lumen (not shown) that extends along the length of the catheter shaft (1222) and is in fluid communication with the hollow interior space (1243) of the irrigation tip (1240). Irrigation fluid communicated from the irrigation lumen to the hollow interior space of the irrigation tip (1240) will be discharged through the main opening (1242).

[0117] Although the reference electrode (1260) is shown as Figure 17 The reference electrode (1260) is located proximal to the distal end of the irrigation tip (1240) and on the outer surface of the tip (1240), but it is within the scope of the present application to have a reference electrode (1260) positioned in the hollow interior space (1243) of the irrigation tip (1240). The wiring (1262) for the electrode (1260) can be embedded in the extruded tip or appropriately mounted to the irrigation lumen. In the version where the reference electrode (1260) is recessed into the hollow interior space (1243), the reference electrode (1260) remains exposed within the hollow interior space (1243) of the irrigation tip (1240), so that blood can enter the hollow interior space (1243) of the irrigation tip (1240) through the main opening (1242) and contact the reference electrode (1260). Alternatively, saline or some other fluid can contact the reference electrode (1260) and thereby provide a reference potential for the reference electrode (1260). As contemplated herein, the reference electrode cannot contact tissue (T). Reference electrode (1260) can acquire a reference potential from blood, saline, or other fluid that passes through the hollow interior space (1243) of irrigation tip (1240). During use of end effector (1230), reference electrode (1260) acquires a reference potential from blood, saline, or the like that enters the hollow interior space (1243) of irrigation tip (1240) (e.g., through opening (1242) or otherwise). A processor of console (12) can process the potentials from irrigation tip (1240) and reference electrode (1260) to provide an electrocardiogram signal as described above.

[0118] When the reference electrode (1260) is used to acquire a reference potential from blood or saline entering the hollow interior space (1243) of the irrigation tip (1240) through the opening (1242), the operator can stop communicating the irrigation fluid to the irrigation tip (1240), thereby allowing blood to enter the tip opening (1242). In some versions, suction is briefly delivered to the irrigation tip (1240) to draw blood into the hollow interior space (1243) of the irrigation tip (1240) through the lateral opening (1242). By way of example only, a separate suction lumen (not shown) may extend along the catheter shaft (1222). Alternatively, the irrigation lumen may be operable to alternate between a state in which irrigation fluid is delivered to the irrigation tip (1240) and a state in which suction is delivered to the irrigation tip (1240). In versions in which suction is provided by irrigation tip (1240), such suction may be very brief—only long enough to draw a sufficient amount of blood into the hollow interior of irrigation tip (1240) through lateral opening (1242) to contact reference electrode (1260) for a sufficient duration to acquire a reference potential from the blood. Various ways in which suction may be incorporated into end effector (1230) will be apparent to those skilled in the art in view of the teachings herein. Alternatively, end effector (1230) may lack suction capabilities altogether.

[0119] F. Exemplary Lasso Tip End Effector with Extendable Ablation Element and Integral Reference Electrode

[0120] Figure 18 Another exemplary end effector (1330) is shown that can be incorporated into the catheter assembly (100) in place of the end effector (130). The end effector (1330) of this example includes an extendable assembly (1380) and a lasso catheter (1332). The extendable assembly (1380) is positioned at the distal end (1324) of the catheter shaft (1322). The extendable assembly (1380) includes an expandable balloon (1382) (at Figure 18 1382) and an array of angularly spaced flexible circuit assemblies (1390). Each flexible circuit assembly (1390) includes a flexible substrate (1392) secured to the balloon (1382). Each flexible circuit assembly (1390) also includes an electrode (1394) secured to the corresponding flexible substrate (1392). The electrodes (1394) are operable to apply RF energy to tissue, thereby ablating the tissue. A hub member (1384) is secured to the distal end of the balloon (1382). The flexible circuit assembly (1390) terminates distally at the hub member (1384).

[0121] The lasso catheter (1332) is coaxially disposed within the catheter shaft (1322) and the extendable assembly (1380) and extends distally through a central opening (1386) formed in a hub member (1384) of the extendable assembly (1380). In some versions, the lasso catheter (1332) is translatable relative to the extendable assembly (1380) to enable selective proximal retraction and distal extension of the lasso catheter (1332) relative to the extendable assembly. The lasso catheter (1332) includes a flexible body (1340) terminating distally in a tip (1350). The body (1340) is resiliently biased to present a Figure 18 The coiled configuration shown in FIG. A plurality of electrodes (1342) are longitudinally spaced apart from one another along the coiled portion of the body (1340). The electrodes (1342) are operable to contact tissue (T) to thereby acquire an electrical potential from the contacted tissue (T).

[0122] The ring electrode (1360) is positioned on the hub member (1384) of the extendable assembly (1380). Although the ring electrode (1360) is shown as being positioned on the distal-most portion of the hub member (1384), the ring electrode (1360) may alternatively be positioned at the proximal or longitudinally intermediate portion of the hub member (1384). The ring electrode (1360) is configured to contact the blood surrounding the end effector (1330), thereby obtaining a reference potential from the blood. The ring electrode (1360) is further positioned and configured to avoid contact with tissue (T) during normal use of the end effector (1330). In some other variations, the ring electrode (1360) is positioned within an interior region of the extendable assembly (1380). In this type of configuration, blood can enter the interior region of the extendable assembly (1380) through the central opening (1386) of the hub member (1384), thereby contacting the electrode (1360). In this version (and other versions), annular electrode (1360) need not necessarily be formed as a ring, but may take any other suitable form.

[0123] During normal use of end effector (1330), one or more electrodes (1342) of lasso catheter (1332) may contact a tissue surface (T), thereby acquiring a potential at the contact area of the tissue surface (T), while ring electrode (1360) acquires a reference potential from blood contacting ring electrode (1360). A processor of console (12) may process the potentials from electrodes (1342, 1360) to provide an electrocardiogram signal as described above.

[0124] By way of further example only, in addition to having the features and functionality described above, the end effector (1330) may be constructed and operated in accordance with at least some of the teachings of U.S. Publication 2017 / 0312022, entitled “Irrigated Balloon Catheter with Flexible Circuit Electrode Assembly,” published on November 2, 2017, the disclosure of which is incorporated herein by reference.

[0125] G. Exemplary Multi-Ray End Effector with Recessed Proximal Reference Electrode

[0126] Figure 19 Another exemplary end effector (330) is shown that can be incorporated into the catheter assembly (100) in place of the end effector (130). The end effector (330) of this example is configured and operable substantially similarly to the end effector (130) described above, such that the same components will not be described in further detail herein. Similar to the end effector (130), the end effector (330) of this example includes a central shaft (350) having a distal opening (352) operable to dispense an irrigation fluid. However, unlike the central shaft (150), the central shaft (350) of this example does not have a ring electrode (154). Instead, a reference electrode (362) is positioned proximal to the arm (140) and the ring electrode (132) on the catheter shaft (122). The reference electrode (362) is positioned in a window (360) formed through the catheter shaft (122) such that the reference electrode (362) is recessed relative to the outer surface of the catheter shaft (122). This recessed positioning prevents the reference electrode (362) from contacting tissue. However, blood can reach the reference electrode (362) through the window (360), so that the reference electrode (362) can obtain a reference potential from the blood contacting the reference electrode (362) through the window (360).

[0127] During use of the end effector (330), one or more electrodes (146, 148) contacting the tissue surface (T) may acquire a potential at the contact area of the tissue surface (T), while the reference electrode (362) acquires a reference potential (362) from the blood contacting the reference electrode. The processor of the console (12) may process the potentials from the electrodes (146, 148, 362) and thereby provide an electrocardiogram signal as described above.

[0128] By way of further example only, in addition to having the features and functionality described above, end effector (330) may be constructed and operated in accordance with at least some of the teachings of U.S. Publication 2016 / 0374753, entitled “Catheter Having Closed Loop Array with In-Plane Linear Electrode Portion,” published on December 29, 2016, the disclosure of which is incorporated herein by reference. U.S. Publication No. 2018 / 0056038, entitled “Catheter with Bipole Electrode Spacer and Related Methods,” published on March 1, 2018, the disclosure of which is incorporated herein by reference; U.S. Patent No. 9,907,480, entitled “Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes,” published on March 6, 2018, the disclosure of which is incorporated herein by reference; U.S. Patent No. 9,949,656, entitled “Catheter with Stacked Spine Electrode Assembly,” published on April 24, 2018, the disclosure of which is incorporated herein by reference; or U.S. Patent No. 9,949,656, entitled “Catheter with Stacked Spine Electrode Assembly,” published on November 21, 2017, the disclosure of which is incorporated herein by reference; Array" (Catheter with a High-Density Electrode Spine Array), the disclosure of which is incorporated herein by reference.

[0129] Furthermore, any of the other aforementioned catheter shafts (210, 522, 622, 722, 822, 922, 1022, 1122, 1222, 1322) may be similar to those described above with reference to Figure 19 The catheter shaft (122) is configured to incorporate a recessed reference electrode (362). Such modifications may be provided in addition to or in lieu of providing the electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) described above.

[0130] H. Exemplary Multi-Ray End Effector with Covered Proximal Reference Electrode

[0131] Figure 20 Another exemplary end effector (430) is shown that can be incorporated into the catheter assembly (100) in place of the end effector (130). The end effector (430) of this example is configured and operable substantially similarly to the end effector (130) described above, such that the same components will not be described in further detail herein. Similar to the end effector (130), the end effector (430) of this example includes a central shaft (450) having a distal opening (452) operable to dispense irrigation fluid. However, unlike the central shaft (150), the central shaft (450) of this example does not have a ring electrode (154). Instead, a reference electrode (462) is positioned proximal to the arm (140) and the ring electrode (132) on the catheter shaft (122). The reference electrode (462) is positioned below the cap member or tissue guard (460). Tissue guard (460) completely surrounds reference electrode (462) and is configured to allow blood to contact reference electrode (462) while preventing tissue from contacting reference electrode (462). Tissue guard (460) is not electrically conductive. By way of example only, tissue guard (460) may be formed from a mesh material, a porous structure, a band having a plurality of openings formed therein, or any other suitable type of construction apparent to one of ordinary skill in the art in view of the teachings herein. Reference electrode (462) is operable to acquire a reference potential from blood contacting reference electrode (462) via tissue guard (460).

[0132] During use of the end effector (430), one or more electrodes (146, 148) contacting the tissue surface (T) may acquire a potential at the contact area of the tissue surface (T), while the reference electrode (462) acquires a reference potential (462) from the blood contacting the reference electrode. The processor of the console (12) may process the potentials from the electrodes (146, 148, 462) and thereby provide an electrocardiogram signal as described above.

[0133] By way of further example only, in addition to having the features and functionality described above, end effector (430) may be constructed and operated in accordance with at least some of the teachings of U.S. Publication 2016 / 0374753, entitled “Catheter Having Closed Loop Array with In-Plane Linear Electrode Portion,” published on December 29, 2016, the disclosure of which is incorporated herein by reference. U.S. Publication No. 2018 / 0056038, entitled “Catheter with Bipole Electrode Spacer and Related Methods,” published on March 1, 2018, the disclosure of which is incorporated herein by reference; U.S. Patent No. 9,907,480, entitled “Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes,” published on March 6, 2018, the disclosure of which is incorporated herein by reference; U.S. Patent No. 9,949,656, entitled “Catheter with Stacked Spine Electrode Assembly,” published on April 24, 2018, the disclosure of which is incorporated herein by reference; or U.S. Patent No. 9,949,656, entitled “Catheter with Stacked Spine Electrode Assembly,” published on November 21, 2017, the disclosure of which is incorporated herein by reference; Array" (Catheter with a High-Density Electrode Spine Array), the disclosure of which is incorporated herein by reference.

[0134] Furthermore, any of the other aforementioned catheter shafts (210, 522, 622, 722, 822, 922, 1022, 1122, 1222, 1322) may be similar to those described above with reference to Figure 20 The described arrangement of the catheter shaft (122) incorporates a reference electrode (462) having a tissue guard (460). Such modifications may be provided in addition to or in lieu of providing electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) as described above.

[0135] I. Dynamic Allocation of Reference Electrodes

[0136] The various end effectors (130, 200, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1330) described above have electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) configured to contact tissue. During normal use of such an end effector (130, 200, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1330), when at least one electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) may be in contact with tissue, at least one other electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) may not be in contact with tissue. However, such non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) may come into contact with blood. Such non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) may therefore be used as reference electrodes, just as the aforementioned electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360). In such examples, electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) may be omitted.

[0137] In some cases where one electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) is used as a reference electrode, a physician (PH) may observe the signals acquired by the electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) to identify electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) that are not in contact with tissue. Such observation may be made based on signal readings presented by a display (18) of the guidance and drive system (10). After identifying the electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) that are not contacting tissue, the physician (PH) may mark the non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) as reference electrodes. In some cases, the physician (PH) may also mark specific tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) for comparison with the user-identified reference electrodes. A processor of console (12) may then process the potentials from the user-identified reference electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) and from the tissue-contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) and thereby provide an electrocardiogram signal as described above.

[0138] As an alternative to having a physician (PH) identify the non-tissue contacting reference electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342), the console's processor (12) may automatically identify the non-tissue contacting electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) and mark the non-tissue contacting electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) as the reference electrode. By way of example only, a processor of console (12) may identify which electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) are contacting tissue and which electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) are not contacting tissue based on the impedance at the electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342). The non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) may have a lower impedance than the tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342).

[0139] As another merely illustrative example, the processor of the console (12) may check the dedicated reference electrode (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) and each of the sensor electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) The impedance between the electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) to identify which sensor electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) are in contact with the tissue and which sensor electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) are not in contact with the tissue. The processor of the console (12) can use this information in any suitable manner, which will be apparent to those skilled in the art in view of the teachings herein.

[0140] In accordance with the foregoing, each end effector (130, 200, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1330) described herein has at least one tissue-contacting electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1240, 1342) and at least one non-tissue-contacting electrode (146, 148, 154, 232, 234, 254, 542, 554, 642, 654, 742, 754, 842, 854, 942, 954, 1042, 1054, 1142, 1154, 1260, 1342, 1360). In the case of electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360), the non-tissue contacting electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) may physically prevent other structures of the end effector (130, 200, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1330) from contacting tissue. In the case of electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342), the non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) occasionally do not contact tissue during certain stages of the EP mapping protocol.

[0141] II. Exemplary Combinations

[0142] The following examples relate to various non-exhaustive ways in which the teachings herein may be combined or applied. It should be understood that the following examples are not intended to limit the coverage of any claims that may be provided at any time in this patent application or subsequent submissions of this patent application. It is not intended to make a disclaimer. The following examples are provided solely for illustrative purposes. It is contemplated that the various teachings herein may be arranged and applied in a variety of other ways. It is also contemplated that some variations may omit certain features mentioned in the following examples. Therefore, any of the aspects or features mentioned below should not be considered decisive unless otherwise expressly indicated as such by the inventor or the inventor's successor at a later date, for example. If any claim set forth in this patent application or subsequent submissions related to this patent application includes additional features other than those mentioned below, these additional features should not be assumed to be added for any reason related to patentability.

[0143] Example 1

[0144] A device comprising: (a) a shaft; and (b) an end effector at a distal end of the shaft, the end effector having a distal end and a proximal end with a longitudinal midpoint between the distal end and the proximal end, the end effector being sized to fit within an anatomical passage within a cardiovascular system, the end effector comprising: (i) at least one sensor electrode configured to contact cardiovascular tissue and thereby acquire an electrical potential, and (ii) a reference electrode configured to acquire an electrical potential from a fluid in contact with the reference electrode, the reference electrode being located proximal to the longitudinal midpoint of the end effector, the end effector being configured to prevent the reference electrode from contacting tissue.

[0145] Example 2

[0146] According to the device described in Example 1, the end actuator defines a profile, the profile having a first portion proximal to the longitudinal midpoint and a second portion proximal to the longitudinal midpoint, the first portion of the profile being proximal to the second portion of the profile, the profile of the end actuator having: (A) a first cross-sectional area at a proximal plane located at the proximal end of the end actuator, the proximal plane defining the proximal boundary of the first portion of the profile, (B) a second cross-sectional area at a midplane, the second cross-sectional area defining the boundary between the first portion and the second portion of the profile, the second cross-sectional area being substantially equal to the first cross-sectional area, and (C) a third cross-sectional area at a distal plane, the third cross-sectional area defining the distal boundary of the second portion of the profile.

[0147] Example 3

[0148] According to the device of embodiment 2, the reference electrode is positioned in the first portion of the contour.

[0149] Example 4

[0150] In the apparatus of embodiment 2, the first portion of the profile is generally cylindrical.

[0151] Example 5

[0152]

[0014] According to the apparatus of embodiment 2, the first portion of the profile is generally polygonal.

[0153] Example 6

[0154] According to the apparatus of any one or more of embodiments 2 to 5, the profile is generally substantially frustoconical.

[0155] Example 7

[0156] According to the apparatus of embodiment 6, the second profile is generally bell-mouth shaped.

[0157] Example 8

[0158] According to the apparatus of embodiment 6, the second profile is generally pyramidal.

[0159] Example 9

[0160] According to the device of any one or more of embodiments 2 to 8, the second profile diverges outwardly from the medial plane to the distal plane.

[0161] Example 10

[0162] In accordance with the apparatus of any one or more of Examples 1-9, the end effector is sized to fit within an anatomical passage within a human cardiovascular system.

[0163] Example 11

[0164] In the apparatus of any one or more of Examples 1 to 10, the end effector further comprises a plurality of elongated spines and a plurality of said sensor electrodes, said sensor electrodes being secured to said spines.

[0165] Example 12

[0166] In the device of embodiment 11, the ridge is configured to prevent tissue from contacting the reference electrode.

[0167] Example 13

[0168] In accordance with the apparatus of any one or more of Examples 11-12, the spines are arranged parallel to one another and connected at a proximal region of the spines to define a generally planar configuration.

[0169] Example 14

[0170] In accordance with the device of any one or more of Examples 11-12, a first pair of ridges are connected at the proximal region to define a first plane, and a second pair of ridges are connected at the proximal region to define a second plane different from the first plane.

[0171] Example 15

[0172]

[00115] The apparatus of any one or more of Examples 11-14, wherein the shaft defines a longitudinal axis, and wherein a portion of each of the ridges extends outwardly away from the longitudinal axis.

[0173] Example 16

[0174]

[00146] In the apparatus of any one or more of Examples 11 to 15, the shaft defines a longitudinal axis, and each of the spines includes a respective free end oriented away from the longitudinal axis.

[0175] Example 17

[0176] In the device of any one or more of Examples 11 to 16, the shaft defines a longitudinal axis, and the end actuator further includes a central axis extending along the longitudinal axis, the central axis being shorter than the spine, such that the reference electrode is positioned on the central axis and is partially obscured by the spine.

[0177] Example 18

[0178] In the apparatus of Example 17, the central shaft of the end effector is further configured to dispense irrigation fluid.

[0179] Example 19

[0180] In accordance with the apparatus of any one or more of Examples 11-18, the shaft defines a longitudinal axis, the spines being configured to arc outwardly and converge distally relative to the longitudinal axis to form a basket-shaped configuration.

[0181] Example 20

[0182] According to the apparatus of embodiment 19, the reference electrode is positioned in an interior region of the basket configuration.

[0183] Example 21

[0184] According to the apparatus of any one or more of Examples 1-20, the shaft defines a longitudinal axis, and the reference electrode comprises a ring coaxially positioned about the longitudinal axis.

[0185] Example 22

[0186] According to the device of any one or more of embodiments 1 to 21, the reference electrode is positioned proximally relative to the at least one sensor electrode.

[0187] Example 23

[0188] A device comprising: (a) a shaft extending along a longitudinal axis; and (b) an end effector at a distal end of the shaft, the end effector being sized to fit within an anatomical passage within a cardiovascular system, the end effector defining a profile oriented relative to the longitudinal axis, the profile creating a frustoconical portion about the longitudinal axis and a cylindrical portion proximal to the frustoconical portion, the end effector comprising: (i) at least one tissue-contacting electrode configured to contact cardiovascular tissue and thereby acquire an electrical potential, and (ii) a non-tissue-contacting electrode configured to acquire a reference potential from a fluid in contact with the non-tissue-contacting electrode, the non-tissue-contacting electrode being positioned in the cylindrical portion of the profile, the end effector being configured to prevent the non-tissue-contacting electrode from contacting tissue.

[0189] Example 24

[0190] 24. The device of embodiment 23, wherein the device is capable of being reprocessed into a reusable device for subsequent reuse.

[0191] Example 25

[0192] 24. The device of embodiment 24, wherein the reprocessed device is cleaned and sterilized with a solution for reuse in a subject.

[0193] Example 26

[0194] 25. The apparatus of embodiment 25, wherein the solution comprises chemicals selected from the group consisting of: 3300-3800 ppm peracetic acid; 2.65% glutaraldehyde; 3.4% glutaraldehyde with 26% isopropyl alcohol; 3.5% glutaraldehyde; 5.75% o-phthalaldehyde; 0.55% o-phthalaldehyde; hypochlorite with 650-675 ppm active free chlorine of hypochlorous acid; 1.12% glutaraldehyde with 1.93% phenol / phenolate; 2.5% glutaraldehyde; 3.2% glutaraldehyde; 3% glutaraldehyde; 7.35% hydrogen peroxide with 0.23% peracetic acid; 1.0% hydrogen peroxide with 0.08% peracetic acid; 2.4% glutaraldehyde; 3.4% glutaraldehyde; 2.0% hydrogen peroxide; 0.60% o-phthalaldehyde; 400-450 ppm hypochlorous acid / hypochlorite with active free chlorine; and combinations thereof.

[0195] Example 27

[0196] A method comprising: (a) placing a first sensor electrode in contact with tissue in the cardiovascular system of a patient; (b) positioning a reference electrode in contact with fluid in the patient's cardiovascular system and not in contact with tissue in the patient's cardiovascular system; (c) processing electrical signals from the first sensor electrode and the reference electrode; (d) plotting an electrocardiogram signal based on the processed electrical signals; and (e) communicating fluid through a lumen, the reference electrode being coaxially positioned around the lumen.

[0197] Example 28

[0198] The method of Example 27, wherein the positioning step includes preventing the reference electrode from contacting tissue with at least one flexible arm extending away from a longitudinal axis of the reference electrode.

[0199] Example 29

[0200] The method of any one or more of Examples 27-28, wherein the first sensor electrode is positioned on a flexible arm extending outwardly from a central longitudinal axis of the shaft, and the reference electrode is positioned about the central longitudinal axis of the shaft.

[0201] Example 30

[0202] The method according to any one or more of Examples 27 to 29 further includes: (a) placing a second sensor electrode in the cardiovascular system of a patient without placing the second sensor electrode in contact with tissue in the patient's cardiovascular system; (b) measuring the impedance between the reference electrode and the first sensor electrode; (c) measuring the impedance between the reference electrode and the second sensor electrode; and (d) determining, based on the measured impedance, that the first sensor electrode is in contact with tissue and the second sensor electrode is not in contact with tissue.

[0203] Example 31

[0204] According to the method described in Example 30, the measured impedance between the reference electrode and the first sensor electrode is greater than the measured impedance between the reference electrode and the second sensor electrode, and the step of determining that the first sensor electrode is in contact with the tissue and the second sensor electrode is not in contact with the tissue includes determining that the measured impedance between the reference electrode and the first sensor electrode is greater than the measured impedance between the reference electrode and the second sensor electrode.

[0205] Example 32

[0206] The method of any one or more of embodiments 27 to 31, wherein the drawing step includes displaying a unipolar signal waveform having a reduction in far-field signal in the range of 50% to 100% compared to a Wilson Center Terminal (WCT) reference signal.

[0207] Example 33

[0208] A device comprising: (a) a shaft; and (b) a tip member positioned at a distal end of the shaft, the tip member defining a hollow interior space and an opening in fluid communication with the hollow interior space; (c) at least one pair of ridges extending from the distal end of the shaft along a longitudinal axis to define a virtual volume surrounding the tip member; and (d) a non-tissue contacting electrode positioned proximate the opening of the tip member, the non-tissue contacting electrode being configured to acquire a reference potential, and the tip member being configured to prevent the non-tissue contacting electrode from contacting tissue.

[0209] Example 34

[0210] Embodiment 33: The apparatus of embodiment 33 wherein the non-tissue contacting electrode is disposed within the interior of the hollow interior space.

[0211] Example 35

[0212] Embodiment 33: The apparatus of embodiment 33 wherein the non-tissue contacting electrode is disposed outside of the hollow interior space.

[0213] Example 36

[0214] A device comprising: (a) a shaft comprising an outer surface defining a lateral window; and (b) an end effector at a distal end of the shaft, the end effector being sized to fit within an anatomical passage within the cardiovascular system, the end effector comprising: (i) at least one sensor electrode configured to contact cardiovascular tissue and thereby acquire an electrical potential, and (ii) a reference electrode configured to acquire an electrical potential from a fluid in contact with the electrode, the reference electrode being accessible through the lateral window, the shaft being configured to prevent tissue from contacting the reference electrode.

[0215] Example 37

[0216] According to the apparatus of embodiment 36, the reference electrode is recessed relative to the outer surface of the shaft.

[0217] Example 38

[0218] A device comprising: (a) a shaft; (b) an end effector at a distal end of the shaft, the end effector being sized to fit within an anatomical passage within the cardiovascular system, the end effector including at least one sensor electrode configured to contact cardiovascular tissue and thereby acquire a potential; (c) an electrode covering member disposed on the shaft; and (d) a reference electrode configured to acquire a potential from a fluid in contact with the reference electrode, the reference electrode being positioned below the electrode covering member, the electrode covering member being configured to allow blood to contact the reference electrode while preventing tissue from contacting the reference electrode.

[0219] Example 39

[0220] According to the apparatus of Example 38, the electrode cover member is porous.

[0221] Example 40

[0222] According to the apparatus of any one or more of Examples 38 to 39, the shaft defines a longitudinal axis and the electrode covering member is coaxially positioned about the longitudinal axis.

[0223] III. Miscellaneous

[0224] Any of the instruments described herein can be cleaned and sterilized before and / or after surgery. In one sterilization technique, the device is placed in a closed and sealed container such as a plastic bag or a TYVEK bag. The container and device can then be placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation can kill bacteria on the device and in the container. The sterilized device can then be stored in a sterile container for later use. The device can also be sterilized using any other technique known in the art, including but not limited to beta or gamma radiation, ethylene oxide, hydrogen peroxide, peracetic acid, and vapor phase sterilization (with or without gas plasma or steam).

[0225] By way of example only, when one of the instruments described herein is cleaned and sterilized before and / or after surgery, the solution may be used for such cleaning and reprocessing. By way of further example only, such a solution may comprise chemicals selected from the group consisting of: 3300-3800 ppm peracetic acid; 2.65% glutaraldehyde; 3.4% glutaraldehyde with 26% isopropyl alcohol; 3.5% glutaraldehyde; 5.75% o-phthalaldehyde; 0.55% o-phthalaldehyde; hypochlorite with 650-675 ppm active free chlorine in hypochlorous acid; 1.12% glutaraldehyde with 1.93% phenol / phenolate; 2.5% glutaraldehyde; 3.2% glutaraldehyde; 3% glutaraldehyde; 7.35% hydrogen peroxide with 0.23% peracetic acid; 1.0% hydrogen peroxide with 0.08% peracetic acid; 2.4% glutaraldehyde; 3.4% glutaraldehyde; 2.0% hydrogen peroxide; 0.60% o-phthalaldehyde; 400-450 ppm hypochlorous acid / hypochlorite with active free chlorine; and combinations thereof. As another merely illustrative example, such a solution may include chemicals selected from the group consisting of: 3100-3400 ppm peracetic acid; 3.4% glutaraldehyde with 20.1% isopropyl alcohol; 2.0% hydrogen peroxide; at least 1820 mg / L peracetic acid; 0.575% o-phthalaldehyde; 0.60% o-phthalaldehyde; hypochlorite and hypochlorous acid with 650-675 ppm active free chlorine; 0.55% o-phthalaldehyde; 7.5% hydrogen peroxide; 2.6% glutaraldehyde; hypochlorite and hypochlorous acid with 400-450 ppm active free chlorine; 0.55% o-phthalaldehyde; and combinations thereof. Cleaning and / or disinfection procedures may be performed in accordance with the U.S. Food and Drug Administration guidance published at https: / / www.fda.gov / medical-devices / reprocessing-reusable-medical-devices-information-manufacturers / fda-cleared-sterilants-and-high-level-disinfectants-general-claims-processing-reusable-medical-and, the disclosure of which is incorporated herein by reference in its entirety.

[0226] By way of example only, when one of the instruments described herein is cleaned and sterilized before and / or after a procedure, such cleaning and reprocessing may be performed using a sterilization system such as those described in U.S. Patent No. 6,939,519, entitled “Power System for Sterilization Systems Employing Low Frequency Plasma,” issued September 6, 2005, the disclosure of which is incorporated herein by reference in its entirety; U.S. Patent No. 6,852,279, entitled “Sterilization with Temperature-Controlled-Led Diffusion Path,” issued February 8, 2005, the disclosure of which is incorporated herein by reference; and U.S. Patent No. 6,852,279, entitled “Sterilization System Employing a Switching Module Adapter to Pulsate the Low Frequency Power Applied to a Sterilization System,” issued February 8, 2005, the disclosure of which is incorporated herein by reference. and U.S. Patent No. 2017 / 0252474, entitled “Method of Sterilizing Medical Devices, Analyzing Biological Indicators, and Linking Medical Device Sterilization Equipment,” published on September 7, 2017, the disclosure of which is incorporated herein by reference in its entirety. Some sterilization systems may use vaporized chemical sterilants or chemical gases such as hydrogen peroxide, peracetic acid, ozone, chlorine dioxide, nitrogen dioxide, etc. to sterilize medical devices.Examples of such systems are described in the following patents: U.S. Patent No. 6,365,102, entitled “Method of Enhanced Sterilization with Improved Material Compatibility,” issued April 2, 2002, the disclosure of which is incorporated herein by reference in its entirety; and U.S. Patent No. 6,325,972, entitled “Apparatus and Process for Concentrating a Liquid Sterilant and Sterilizing Articles Therewith,” issued December 4, 2001, the disclosure of which is incorporated herein by reference in its entirety.

[0227] It should be understood that any examples described herein may also include various other features in addition to or as an alternative to those described above. By way of example only, any examples described herein may also include one or more of the various features disclosed in any one of the various references incorporated herein by reference.

[0228] It should be understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. described herein. Therefore, the above teachings, expressions, embodiments, examples, etc. should not be considered in isolation from each other. Various suitable ways in which the teachings herein can be combined will be apparent to those skilled in the art with reference to the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

[0229] It should be understood that any patent, patent publication, or other public material, whether in whole or in part, allegedly incorporated herein by reference is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other public materials set forth in this disclosure. Accordingly, and to the extent necessary, the disclosure expressly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, allegedly incorporated herein that conflicts with existing definitions, statements, or other public materials set forth herein will be incorporated only to the extent that no conflict arises between the incorporated material and the existing public materials.

[0230] While various versions of the present invention have been shown and described, further improvements to the methods and systems described herein may be achieved by appropriate modifications by one of ordinary skill in the art without departing from the scope of the invention. Several such possible modifications have been mentioned, and other modifications will be apparent to those skilled in the art. For example, the examples, versions, geometries, materials, dimensions, ratios, steps, etc. discussed above are exemplary and not required. Accordingly, the scope of the present invention should be considered in light of the appended claims and should be understood not to be limited to the details of structure and operation shown and described in the specification and drawings.

Claims

1. An electrophysiological mapping device, comprising: (a) First axis; as well as (b) an end effector at the distal end of the first shaft, the end effector having a distal end and a proximal end with a longitudinal midpoint between the distal and proximal ends of the end effector, the end effector being sized to fit within an anatomical passage within the cardiovascular system, the end effector comprising: (i) a plurality of elongated spines having proximal ends at the distal end of the first shaft, the plurality of elongated spines extending distally from the distal end of the first shaft, each elongated spine carrying at least one sensor electrode, the at least one sensor electrode configured to contact cardiovascular tissue and thereby acquire an electrical potential, and (ii) a central end effector shaft extending distally from the distal end of the first shaft, the central end effector shaft being shorter than the plurality of elongated spines and terminating at its distal end, the distal end of the central end effector shaft being proximal to the distal end of the end effector and adjacent to the proximal ends of the plurality of elongated spines, the central end effector shaft carrying a reference electrode configured to acquire an electrical potential from a fluid in contact with the reference electrode, the central end effector shaft carrying the reference electrode at a location proximal to the longitudinal midpoint of the end effector and adjacent to the proximal ends of the plurality of elongated spines, the plurality of elongated ridges being configured to prevent the reference electrode from contacting tissue; wherein the end effector defines a profile having a first portion proximal to the longitudinal midpoint and a second portion proximal to the longitudinal midpoint, the first portion of the profile being proximal to the second portion of the profile, the profile of the end effector having: (A) a first cross-sectional area at a proximal plane located at the proximal end of the end effector, the proximal plane defining a proximal boundary of the first portion of the profile, (B) a second cross-sectional area at a mid-plane, the second cross-sectional area defining a boundary between the first portion and the second portion of the profile, the second cross-sectional area being substantially equal to the first cross-sectional area, and (C) a third cross-sectional area at a distal plane, the third cross-sectional area defining a distal boundary of the second portion of the profile; Wherein, the reference electrode is positioned in the first portion of the contour.

2. The apparatus of claim 1, the first portion of the profile being generally cylindrical. The apparatus of claim 1 , wherein the first portion of the profile is generally polygonal.

4. The apparatus of claim 1, the second portion of the profile being generally frustoconical.

5. The apparatus of claim 1, the second portion of the profile being generally bell-mouth shaped. The apparatus of claim 1 , wherein the second portion of the profile is generally pyramidal.

7. The apparatus of claim 1, the second portion of the profile diverging outwardly from the medial plane to the distal plane.

8. The apparatus of claim 1, the end effector being sized to fit within an anatomical passage within the human cardiovascular system.

9. The apparatus of claim 1, the at least one sensor electrode comprising a plurality of sensor electrodes carried on respective ones of the plurality of elongated ridges.

10. The apparatus of claim 1, the elongated spines disposed parallel to one another and connected at proximal regions of the elongated spines to define a generally planar configuration.

11. The apparatus of claim 1 , a first pair of elongated spines connected at a proximal region to define a first plane, and a second pair of elongated spines connected at a proximal region to define a second plane different from the first plane.

12. The apparatus of claim 1, the first shaft defining a longitudinal axis, a portion of each of the elongated spines extending outwardly away from the longitudinal axis.

13. The apparatus of claim 1, the first shaft defining a longitudinal axis, each of the elongated spines including a respective free end oriented away from the longitudinal axis.

14. The apparatus of claim 1 , wherein the first shaft defines a longitudinal axis, the central end effector shaft extending from a distal end of the first shaft along the longitudinal axis of the first shaft such that the reference electrode is positioned on the central end effector shaft and partially obscured by the elongated spine.

15. The apparatus of claim 14, the central end effector shaft of the end effector further configured to dispense irrigation fluid.

16. The apparatus of claim 1, the first shaft defining a longitudinal axis, the elongated spines being configured to arc outwardly and converge distally relative to the longitudinal axis to form a basket-shaped configuration.

17. The apparatus of claim 16, the central end effector shaft carrying the reference electrode such that it is positioned within an interior region of the basket configuration.

18. The apparatus of claim 1, the first shaft defining a longitudinal axis, the reference electrode comprising a ring coaxially positioned about the longitudinal axis.

19. The apparatus of claim 1, the reference electrode positioned proximally relative to the at least one sensor electrode.

Images