Monopolar reference electrode for electrophysiology mapping catheter

Abstract

The invention relates to a unipolar reference electrode for electrophysiology mapping catheters. An apparatus is provided that includes a shaft and an end effector at a 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 channel within the cardiovascular system. The end effector includes 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 electric potential. The reference electrode is configured to draw an electric potential from a fluid in contact with the reference electrode. The reference electrode is located proximal to a longitudinal midpoint of the end effector. The end effector is configured to prevent the reference electrode from contacting tissue.

Description

Background Art

[0001] When electrical signals are abnormally conducted in regions of heart tissue, arrhythmias such as atrial fibrillation occur. Procedures for treating arrhythmias include surgically interrupting the conduction pathways for such signals. Selectively ablating heart tissue by applying energy (e.g., radiofrequency (RF) energy) may 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 unwanted electrical pathways by creating an electrically insulating lesion or scar tissue.

[0002] In some procedures, a catheter having 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 electrodes within the heart or in cardiovascular structures adjacent to the heart (e.g., the pulmonary veins). The electrodes can be placed in contact with heart tissue or other vascular tissue and then activated with RF energy to ablate the contacted tissue. In some cases, the electrodes can be bipolar. In some other cases, monopolar electrodes 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 January 31, 2013, titled "Integrated Ablation System using Catheter with Multiple Irrigation Lumens", the disclosure of which is incorporated herein by reference; U.S. Publication 2017 / 0312022, published November 2, 2017, titled "Irrigated Balloon Catheter with Flexible Circuit Electrode Assembly", the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0071017, published March 15, 2018, titled "Ablation Catheter with a Flexible Printed Circuit Board", the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0056038, published March 1, 2018, titled "Catheter with Bipole Electrode Spacer and Related Methods", the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0036078, published February 8, 2018, titled "Catheter with Soft Distal Tip for Mapping and Ablating Tubular Region", the disclosure of which is incorporated herein by reference; U.S. Patent 8,956,353, titled "Electrode Irrigation Using Micro-Jets", published February 17, 2015, the disclosure of which is incorporated herein by reference; and U.S. Patent 9,801,585, titled "Electrocardiogram Noise Reduction", published October 31, 2017, the disclosure of which is incorporated herein by reference.

[0004] Some catheter ablation procedures may be performed using electrophysiology (EP) mapping. Such EP mapping may include using sensing electrodes on a catheter (e.g., the same catheter used to perform ablation). Such sensing electrodes may monitor electrical signals within the cardiovascular system to precisely determine the location of the arrhythmogenic abnormal conductive tissue sites. Examples of EP mapping systems are described in U.S. Patent 5,738,096, titled "Cardiac Electromechanics," published 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, titled "Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes," published on March 6, 2018, the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0036078, titled "Catheter with Soft Distal Tip for Mapping and Ablating Tubular Region," published on February 8, 2018, the disclosure of which is incorporated herein by reference; and U.S. Publication 2018 / 0056038, titled "Catheter with Bipole Electrode Spacer and Related Methods," published on March 1, 2018, the disclosure of which is incorporated herein by reference.

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

[0006] Although several surgical systems and methods have been made and used, it is believed that no one prior to the present inventor 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 merely exemplary and are not intended to limit the scope of the invention as envisioned by the present inventor.

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

[0009] Figure 2 Shows Figure 1 a top plan view of the catheter assembly of

[0010] Figure 3 Shows Figure 1 a perspective view of the end effector of the catheter assembly of

[0011] Figure 4 Shows Figure 3 a side schematic view of the end effector of

[0012] Figure 5 Shows Figure 1 a perspective view of the end of the distal end of the catheter assembly of , where the end effector arms are omitted, and where the schematic view of the end effector profile includes a cylindrical portion and a flared frustoconical portion;

[0013] Figure 6 Shows Figure 1 a perspective view of the end of the distal end of the catheter assembly of , where the end effector arms are omitted, and where the schematic view of the end effector profile includes a cylindrical portion and a pyramidal frustoconical portion;

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

[0015] Figure 8 Shows Figure 1 a side elevation view of an exemplary alternative end effector that can be incorporated into the catheter assembly of ;

[0016] Figure 9 Shows Figure 8 an enlarged side view of a portion of the central axis of the end effector of ;

[0017] Figure 10 Shows Figure 1 a side elevation view of another exemplary alternative end effector that can be incorporated into the catheter assembly of ;

[0018] Figure 11 Shows a side elevation view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0019] Figure 12 Shows a side elevation view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0020] Figure 13 Shows a side elevation view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0021] Figure 14 Shows a side elevation view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0022] Figure 15 Shows a side elevation view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0023] Figure 16 Shows a side elevation view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0024] Figure 17 Shows an enlarged perspective view of the tip of a catheter assembly that can be incorporated into a Figures 10 - 16 catheter assembly;

[0025] Figure 18 Shows a perspective view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly;

[0026] Figure 19 Shows a perspective view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly; and

[0027] Figure 20 Shows a perspective view of another exemplary alternative end effector that can be incorporated into a Figure 1 catheter assembly. DETAILED DESCRIPTION

[0028] The following description of certain examples of the invention is not intended to limit the scope of the invention. The accompanying drawings (not necessarily to scale) illustrate selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates the principles of the invention in an illustrative rather than a restrictive manner. Other examples, features, aspects, embodiments, and advantages of the invention will be apparent to those skilled in the art from the following description, which is presented by way of example. A best mode is contemplated for carrying out the invention. As will be recognized, the invention is capable of having other different or equivalent aspects, all of which do not depart from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature rather than restrictive.

[0029] Any one or more of the teachings, expressions, forms, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, forms, examples, etc. described herein. Accordingly, the following teachings, expressions, forms, examples, etc. should not be regarded as mutually separate. Various suitable ways in which the teachings herein may be combined will be apparent to those skilled in the art in view of 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” in reference to any numerical value or range means a reasonable dimensional tolerance that allows a component or collection of components to perform its intended purpose as described herein. More specifically, “about” or “approximately” can refer to a range of values of ± 10% of the recited value, e.g., “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 the system or method 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 can be performed using unipolar electrodes. Some conventional unipolar EP mapping techniques can include comparing the potential obtained by one unipolar electrode with the potential obtained by a remote reference electrode. An example of such a technique is the Wilson central terminal (WCT), which includes an average of the three limb leads. Another technique can include using an electrode on a first catheter to obtain the potential at the tissue region of interest and using an electrode on a second catheter to obtain a reference potential. For example, the electrode on the first catheter can obtain the potential at the tissue in the pulmonary vein (PV), while the electrode on the second catheter can obtain the reference potential in the inferior vena cava (IVC).

[0034] As an alternative form to conventional unipolar EP mapping techniques, it is desirable to obtain a reference potential from the blood near the tissue from which the tissue potential is acquired. In other words, it is desirable to place a first electrode in contact with the tissue to acquire a potential from the tissue; and to place a second electrode in contact with the blood near the contacted tissue to acquire a reference potential from the blood. The second (reference) electrode may contact only the blood and not the tissue. The blood may provide an accurate reference potential for the heart. By keeping the second (reference) electrode away from contact with the tissue, the second (reference) electrode can avoid acquiring local tissue potentials that could otherwise compromise the reliability of the sensed reference potential. This configuration may provide beneficial effects similar to those obtained with bipolar EP mapping devices and techniques, such as reduced noise and reduced far-field signals, since the reference electrode is located in the same ventricle as the tissue contact electrode; while still maintaining the characteristics of the unipolar signal, since the direct tissue potential is acquired by only a single electrode. By way of example only, this configuration may provide a reduction in far-field signals of from about 50% to about 100% compared to far-field signals obtained with 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 the unconventional unipolar EP mapping described above are shown. Specifically, Figure 1 a doctor (PH) is shown grasping the handle (110) of a catheter assembly (100), where the end effector (130) of the catheter (120) of the catheter assembly (100) (shown in Figures 2 - 4 but not shown in Figure 1 ) is disposed within a patient (PA) to perform EP mapping within or near the patient's (PA) heart (H). As Figure 2 shown, the catheter (120) includes an elongate flexible shaft (122), where the end effector (130) is disposed at the distal end (124) of the shaft (122). The end effector (130) and its variations will be described in more detail below. The catheter assembly (100) is coupled to a steering 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 only optional. A set of field generators (20) are positioned beneath the patient (PA) and are coupled to the steering and drive system (10) via another cable (22). The field generators (20) are also only 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 drive module (14) and a second drive module (16). The first drive module (14) is coupled to a catheter assembly (100) via a cable (30). In some variations, the first drive module (14) is operable to receive an EP mapping signal 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 drive module (14) is operable to provide RF power to the electrodes (132, 146, 148) of the end effector (130) to ablate tissue. In some configurations, the first drive module (14) is also operable to receive a position indication signal from a position sensor (not shown) in the end effector (130), as will be described in more detail below. In this type of configuration, the processor of the console (12) is also operable to process the position indication signal from the position sensor to determine the position of the end effector (130) of the catheter (120) within a patient (PA).

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

[0038] As described above, some configurations of the end effector (130) include a position sensor (not shown) that is operable to generate a signal indicative of the position and orientation of the end effector (130) within a patient (PA). Each position sensor may include a coil or multiple wire coils (e.g., three orthogonal coils) that are 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, etc. By way of example only, position sensing may be provided in accordance with at least some of the teachings of U.S. Patent 9,480,416, the disclosure of which is incorporated herein by reference. Alternatively, the end effector (130) may not have a position sensor.

[0039] The display (18) is coupled to the processor of the console (12) and is operable to render an image of a patient's anatomy. Such an image may be based on a set of pre-operative or intra-operative acquired images (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 signals from a position sensor of the end effector (130). For example, when 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). Additionally, the processor of the console (12) may drive the display (18) to show the location of an abnormal conductive tissue site detected by performing EP mapping with the end effector (130). By way of example only, the processor of the console (12) may drive the display (18) to superimpose the location of the abnormal conductive tissue site on the image of the patient's anatomy, such as by overlaying an illuminated point, a crosshair, or some other form of visual indication of the abnormal conductive tissue site.

[0040] The processor of the console (12) may 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 overlaying an illuminated point, a crosshair, a graphical representation of the end effector (130), or some other form of visual indication. When the doctor moves the end effector (130) within the patient (PA), such superimposed visual indication may also move within the image of the patient's anatomy on the display (18), thereby providing real-time visual feedback to the operator 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) may effectively provide a video tracking the position of the end effector (130) within the patient (PA) without necessarily having any optical instrument (i.e., camera) for viewing the end effector (130). In the same view, the display (18) may simultaneously visually indicate the location of an abnormal conductive tissue site detected by EP mapping as described herein. The doctor (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 sites and relative to the image of adjacent anatomy within the patient (PA).

[0041] The fluid source (42) of this example includes a bag containing saline or some other suitable flushing fluid. The conduit (40) includes 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 completely omitted. In configurations including these components, the end effector (130) can be configured to deliver the flushing fluid from the fluid source (42) to a target site within a patient's body. Such flushing can be provided in accordance with the teachings of any one of the various patent references cited herein; or in any other suitable manner that would be apparent to one of ordinary skill in the art in view of the teachings herein.

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

[0043] Figures 2 - 4 The end effector (130) is shown in more detail. The end effector (130) and other aspects of the catheter assembly (100) can be configured and operated in accordance with 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) that extend distally from the distal end of the catheter shaft (122). The arms (140) generally radiate outwardly away from the central longitudinal axis (L-L) of the catheter shaft (122). In this example, the end effector (130) has five arms (140). In some other configurations, the end effector (130) has eight arms (140). Alternatively, the end effector (130) can have any other suitable number of arms (140).

[0044] Each arm (140) includes a flexible elongate body (142) having a respective set of longitudinally spaced pairs of annular electrodes (146, 148). Each arm (140) terminates distally at a respective free end. In this example, each arm (140) has four pairs of electrodes (146, 148). Alternatively, more or fewer than four pairs of electrodes (146, 148) may be provided on each arm (140). Each pair of electrodes (146, 148) is separated from one another by a corresponding gap (144). In this example, each pair of electrodes (146, 148) is configured to provide bipolar sensing of an electrocardiogram signal 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) of each pair may be used to provide unipolar sensing without using the other electrode (146, 148) of the pair. The catheter assembly (100) also enables a doctor (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 provided in pairs such that each arm (140) has only an electrode array (146) or an electrode array (148).

[0045] The end effector (130) also 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) may also be configured to cooperate in pairs to provide bipolar sensing of an electrocardiogram signal when the electrodes (132) are placed in contact with cardiovascular tissue. Alternatively, one or more of the electrodes (132) may be used to provide unipolar sensing. In some other configurations, one or all of the electrodes (132) are omitted.

[0046] The end effector (130) also includes a central shaft (150) that projects distally from the distal end (124) of the catheter shaft (122) and is proximal to 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 is in fluid communication with a lumen formed along the length of the central shaft (150). The lumen is in fluid communication with a fluid conduit (40) that is further in communication with a fluid source (42) as described above. Accordingly, the central shaft (150) is operable to dispense a flushing fluid (e.g., saline) from the fluid source (42) to a site within a patient (PA) (e.g., within a cardiovascular structure) via the distal opening (152). In some other configurations, the central shaft (150) does not have a distal opening (152) and is not otherwise capable of dispensing a flushing fluid.

[0047] The central axis (150) of this example also includes an annular 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 a patient (e.g., in a pulmonary vein, etc.), the annular electrode (154) is positioned to contact the blood. However, the arm (140) is also configured to prevent the annular electrode (154) from contacting tissue when the end effector (130) is disposed within the cardiovascular structure. Thus, during normal use, one or more electrodes (146, 148) will contact the tissue while the annular electrode (154) does not contact the tissue. For example, as Figure 4 shown, a doctor (PH) can force the end effector (130) against the tissue surface (T). This can cause one or more arms (140) to flatten generally along the tissue surface (T), thereby placing the electrodes (146, 148) in direct contact with the tissue surface (T). However, the annular electrode (154) can be spaced from the tissue surface (T) by a gap (G). Even if the doctor continues to push the end effector (130) further distally toward the tissue surface (T) and even if the arm (140) is capable of further outwardly spreading, the distal end of the central axis (150) will contact the tissue surface (T) before the annular electrode (154) contacts the tissue surface (T). Thus, during normal use of the end effector (130), the annular electrode (154) will not contact the tissue surface (T).

[0048] Although the annular electrode (154) does not contact the tissue surface (T), the annular electrode (154) will still contact the blood flowing through the cardiovascular system. For example, if the end effector (130) is positioned in a pulmonary vein, one or more electrodes (146, 148) can contact the tissue surface (T) while the annular electrode (154) contacts the blood flowing through the pulmonary vein. One or more electrodes (146, 148) that contact the tissue surface (T) can acquire a potential at the contact area of the tissue surface (T), while the annular electrode (154) acquires a reference potential from the blood in which the annular electrode (154) is disposed. A processor of the console (12) can 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, can allow the doctor (PH) to identify the most appropriate areas of cardiac tissue to ablate (e.g., with RF energy, cryoablation, etc.) to prevent or at least reduce the propagation of abnormal electrical activity across the cardiac tissue.

[0049] Figure 5 An exemplary three-dimensional profile (160) is shown that can be defined by at least the proximal portion of the arm (140). Although Figure 5The arm (140) is omitted in [description], but it should be understood that at least the proximal portion of the arm (140) is generally arranged around a boundary depicted as a three-dimensional profile (160). In some embodiments, the arm (140) is elastically biased such 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 an intermediate plane (164). The proximal plane (166) is located at the distal end (124) of the catheter axis (122). The flared frustoconical portion (170) is bounded proximally by the intermediate plane (164) and distally by a distal plane (172).

[0050] In some embodiments, the distal plane (172) is located at the free end or distal tip of the arm (140) such that the arm (140) terminates distally at the distal plane (172). In some other embodiments, the arm (140) continues to extend distally along a respective straight path 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 a respective distal straight portion and a proximal straight portion of each arm (140). In some embodiments where the arm (140) extends distally along a respective straight path at the distal plane (172), these respective straight paths are oriented obliquely away from the longitudinal axis (L-L) of the catheter axis (122). Figure 7 An example of such a configuration is shown in [description], which depicts only one arm (140) of the end effector (130), and it should be understood that the other arms (140) may be similarly configured (although arranged in an angularly spaced array).

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

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

[0053] In this example, the intermediate plane (164) represents a longitudinal position where the arms (140) transition from a generally straight direction and are parallel to each other to flare out away from each other along respective 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 intermediate 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 regions (Ap, Ai, Ad) are shown as being orthogonal to the longitudinal axis (L-L) in the exemplary drawings, since the configuration of the arms (140) is symmetric about the longitudinal axis (L-L), the flaring of the arms (140) does not necessarily have to be symmetric with respect to the longitudinal axis (L-L), and thus the proximal plane, intermediate plane, and distal plane of the respective regions (Ap, Ai, Ad) may intersect each other or otherwise be non-orthogonal with respect to the longitudinal axis (L-L).

[0054] In this example, the central axis (150) and the annular electrode (154) are configured and positioned such that the longitudinal position of the electrode (154) corresponds to the cylindrical portion (162) of the three-dimensional profile (160). Accordingly, the annular electrode (154) is positioned proximally with respect to the intermediate plane (164). Thus, the annular electrode (154) can be considered to be masked by the cylindrical portion (162) of the three-dimensional profile (160) defined by the arms (140) of the end effector (130). In some other configurations, the central axis (150) and the annular electrode (154) are configured and positioned such that the annular electrode (154) is longitudinally positioned between the distal plane (172) and the intermediate plane (164). In this type of configuration, the annular electrode (154) can be considered to be masked by the flared frustoconical portion (170) of the three-dimensional profile (160) defined by the arms (140) of the end effector (130).

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

[0056] Figure 6 shows another exemplary three-dimensional profile (180), which may be defined by at least the proximal portion of the arm (140). Although Figure 6 the arm (140) is omitted therefrom, it should be understood that at least the proximal portion of the arm (140) is generally disposed around the boundary depicted as the three-dimensional profile (180). In some configurations, the arm (140) is elastically biased such that at least the proximal portion of the arm (140) defines the three-dimensional profile (180). The exemplary three-dimensional profile (180) includes a cylindrical portion (162) and a frustoconical portion (190). The cylindrical portion (162) is bounded proximally by a proximal plane (166) and distally by an intermediate plane (164). The proximal plane (166) is located at the distal end (124) of the catheter axis (122). The frustoconical portion (190) is bounded proximally by the intermediate plane (164) and distally by a distal plane (192).

[0057] In some configurations, the distal plane (192) is located at the free end or distal tip of the arm (140) such that the arm (140) terminates distally at the distal plane (192). In some other configurations, the arm (140) continues to extend distally along the respective straight path at the distal plane (192) such that the frustoconical portion (190) represents an intermediate angled portion of each arm (140) that is longitudinally interposed between the respective distal and proximal straight portions of each arm (140). In some configurations where the arm (140) extends distally along the respective straight path at the distal plane (192), these respective straight paths are oriented obliquely away from the longitudinal axis (L-L) of the catheter axis (122) (e.g., at an angle greater than the angle represented by the frustoconical portion (190)). In some other configurations where the arm (140) extends distally along the respective straight path at the distal plane (192), these respective straight paths are parallel to the longitudinal axis (L-L) of the catheter axis (122). In either case or in other configurations, it should be understood that the arm (140) may continue to extend distally beyond the distal plane (192) such that the distal plane (192) should not be considered to necessarily correspond to the distal end of the end effector (130).

[0058] In the present example, the intermediate plane (164) represents the longitudinal position where the arms (140) transition from a generally straight direction and are parallel to each other to flare outwardly away from each other along respective angled paths. The cross-sectional area of the region of the proximal plane (166) of the three-dimensional profile (180) is approximately equal to the cross-sectional area of the region of the intermediate plane (164) of the three-dimensional profile (180). The cross-sectional area of the region 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 axis (150) and the annular electrode (154) are configured and positioned such that the longitudinal position of the electrode (154) corresponds to the cylindrical portion (162) of the three-dimensional profile (180). Accordingly, the annular electrode (154) is positioned proximally relative to the intermediate plane (164). Thus, the annular electrode (154) can be considered to be masked by the cylindrical portion (162) of the three-dimensional profile (180) defined by the arm (140) of the end effector (130). In some other configurations, the central axis (150) and the annular electrode (154) are configured and positioned such that the annular electrode (154) is longitudinally positioned between the distal plane (192) and the intermediate plane (164). In this type of configuration, the annular electrode (154) can be considered to be masked by the frustoconical portion (190) of the three-dimensional profile (180) defined by the arm (140) of the end effector (130).

[0060] By having the frustoconical portion (190) or the cylindrical portion (162) of the three-dimensional profile (190) defined by the arm (140) of the end effector (130) mask the annular electrode (154), the blood flow around the annular electrode (154) can be relatively smooth, which can enable the annular electrode (154) to acquire electrical potential from the blood in a relatively reliable manner. In other words, the arrangement of the arm (140) around the annular electrode (154) can affect the blood flow around the electrode (154) such that the turbulence of the flow can be less than if the annular electrode (154) were positioned elsewhere; and acquiring electrical potential from the blood through the annular electrode (154) can be more reliable than might be the case if the annular electrode (154) were positioned elsewhere. When the annular electrode (154) is masked by the cylindrical portion (162), the reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (154) can be particularly enhanced.

[0061] C. Exemplary Basket End - Effector with a Reference Electrode on the Inner Shaft

[0062] Figure 8Shown is another exemplary end effector (200) that can be incorporated into a catheter assembly (100) to replace the end effector (130). The exemplary end effector (200) of this example includes an extensible assembly (220) formed by an array of beams (222) that are angularly spaced. Each beam (222) includes four pairs (230) of bipolar electrodes (232, 234). Each of the electrodes (232, 234) is generally rectangular and is configured to obtain electrical potentials from tissue, similar to the electrodes (146, 148) described above. The electrodes (232, 234) can be used in bipolar or monopolar fashion. In this example, the entirety of each electrode (232, 234) is confined to the outwardly presented surface of each beam (222). Thus, the beams (222) have electrodes (232, 234) only on one side of each beam (222) (i.e., the tissue contact side of each beam (222)).

[0063] The proximal ends of the beams (222) are positioned within an outer shaft (210) that can be considered similar to the catheter shaft (122) described above. The distal ends of the beams (222) are coupled to a hub member (212). The hub member (212) is fixed to a central inner shaft (250) that is coaxially positioned at the center of the extensible assembly (220). The beams (222) are configured to transition the extensible assembly (220) between a non-extended state and an extended state. The extended state is shown in Figure 8 When the extensible assembly (220) is in the non-extended state, the beams (222) are pushed inwardly to define an effective outer diameter that is less than or equal to the inner diameter of the outer shaft (210). In some configurations, the beams (222) are elastically biased to provide the extensible assembly (220) in the extended state. In some such configurations, an 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 extensible assembly (220) in the non-extended state. When the sheath (214) is in a proximal position (e.g., as shown in Figure 8 such that the distal end of the sheath (214) is proximal to the extensible assembly (220)), the beams (222) can elastically provide the extensible assembly (220) in the extended state.

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

[0065] As Figure 8 shown, the configuration of the end effector (200) can be considered in relation to three planes (264, 266, 272) that are perpendicular to the longitudinal axis (L-L) of the shafts (210, 250). The proximal plane (266) is located at the distal end of the shaft (210) and at the proximal end of the end effector (200). The intermediate plane (264) is distal to the proximal plane (266). The distal plane (272) is distal to the intermediate plane (264). The longitudinal region of the end effector (200) between the planes (264, 266) can be considered to define a cylindrical portion (262) that defines a cylindrical three-dimensional profile, very similar to the cylindrical portion (162) described above with respect to Figures 5 - 6 the cylindrical portion (162) described above. Thus, the portion of the beam (222) that extends along the cylindrical portion (262) can extend along a corresponding straight path parallel to the longitudinal axis (L-L) of the shafts (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 Figure 5The described 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 (L-L) of the axes (210, 250). The portion of the beam (222) extending distally from the distal plane (272) curves inwardly back towards the longitudinal axis (L-L) of the axes (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 a corresponding curved path to extend inwardly along a corresponding curved path.

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

[0067] Thus, the beam (222) is configured to prevent tissue from contacting the annular electrode (254). However, the beam (222) allows blood to flow through the expandable assembly (220), thereby allowing blood to contact the annular 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 the potential at the contact area of the tissue surface (T), while the annular electrode (254) acquires a reference potential from the blood in which the annular electrode (254) is disposed. The processor of the console (12) can process the potentials from the electrodes (232, 234, 254) and thereby provide the electrocardiogram signal as described above.

[0068] By masking the annular electrode (254) with the flared frustoconical portion (190) or the cylindrical portion (262) of the three-dimensional profile defined by the beam (222) of the end effector (200), the blood flow around the annular electrode (254) can be relatively smooth, which enables the annular electrode (254) to acquire electrical potential from the blood in a relatively reliable manner. In other words, the arrangement of the beam (222) around the annular electrode (254) can affect the blood flow around the electrode (254), such that the turbulence of the flow can be less than if the annular electrode (254) were positioned elsewhere; and the acquisition of electrical potential from the blood through the annular electrode (254) is more reliable than would be possible if the annular electrode (254) were positioned elsewhere. When the annular electrode (254) is masked by the cylindrical portion (262), the reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (254) can be particularly enhanced.

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

[0070] Figure 10 Another exemplary end effector (530) that can be incorporated into the catheter assembly (100) in place of the end effector (130) is shown. The exemplary end effector (530) of this example includes outer arms (540) and outer arms (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 elastic connection members (546) at the distal ends of each ring. The longitudinal intermediate 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 be laterally bent away from the central longitudinal axis (L-L) 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 laterally pressed against tissue. The arms (540, 544) can be elastically biased to return to the Figure 10 flat planar configuration shown. In some other configurations, portions of the arms (540, 544) are further offset from each other such that the arms (540, 544) are not positioned along a single flat plane.

[0072] The proximal ends of the arms (540, 544) extend along respective straight paths between a proximal plane (566) and an intermediate plane (564), the straight paths being generally parallel to each other and generally parallel to the longitudinal axis (L-L) of the catheter shaft (522). The most proximal regions of the arms (540, 544) between the planes (564, 566) together define a generally rectangular first 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 intermediate plane (564) to a distal plane (572). The arms (540, 544) thus extend outwardly along respective diverging paths through the second portion (570). As described above, distal to the distal plane (572), the arms (540, 544) extend along respective straight 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 configurations, the electrodes (542) are arranged in pairs, such as the electrodes (146, 148) described above.

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

[0075] When the annular electrode (554) is covered by the first portion (562) or the second portion (570), the arms (540, 544) generally prevent tissue from contacting the annular electrode (554). However, the arms (540, 544) allow blood to flow through the end effector (530), thereby allowing the blood to contact the annular 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 annular electrode (554) obtains a reference potential from the blood in which the annular electrode (554) is disposed. The processor of the console (12) can process the potentials from the electrodes (542, 554) to provide the electrocardiogram signal as described above.

[0076] By covering the annular electrode (554) with the first portion (562) or the second portion (570) of the profile defined by the arms (540, 544) of the end effector (530), the blood flow around the annular electrode (554) can be relatively smooth, which can enable the annular electrode (554) to obtain a potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (540, 544) around the annular electrode (554) can affect the blood flow around the electrode (554) such that the turbulence of the flow can be less than if the annular electrode (554) were positioned elsewhere; and the potential obtained from the blood by the annular electrode (554) is more reliable than might be the case if the annular electrode (554) were positioned elsewhere. The reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (554) can be particularly enhanced when the annular electrode (554) is covered by the first portion (562).

[0077] Figure 11Another exemplary end effector (630) is shown that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary 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 forms, the distal ends of the arms (640, 644) are simply fixed together by welding, adhesion, or otherwise to form the joint (646). The longitudinal intermediate 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) generally converge at the joint (646). In this example, the arms (640, 644) are all positioned along a single flat plane. However, the arms (640, 644) are also flexible such that the arms (640, 644) can be laterally bent away from the central longitudinal axis (L-L) 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 laterally pressed against tissue. The arms (640, 544) can be elastically biased to return to Figure 11 the flat planar configuration shown. In some other forms, portions of the arms (640, 644) are further offset from each other such that the arms (640, 644) are not positioned along a single flat plane.

[0078] The proximal ends of the arms (640, 644) extend along respective straight paths between a proximal plane (666) and an intermediate plane (664), the straight paths generally being parallel to each other and generally parallel to the longitudinal axis (L-L) of the catheter shaft (622). The most proximal regions of the arms (640, 644) between the planes (664, 666) together define a generally rectangular first 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 intermediate plane (664) to the distal plane (672). The arms (640, 644) thus extend outwardly along respective diverging paths through the second portion (670). As described above, distal to the distal plane (672), the arms (640, 644) extend along respective straight 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 forms, the electrodes (642) are arranged in pairs, such as the electrodes (146, 148) described above.

[0080] The end effector (630) further includes a central inner shaft (650) having an annular electrode (654). The annular electrode (654) is coaxially disposed around the inner shaft (650). In the present example, the annular electrode (654) is longitudinally positioned between the planes (664, 672) such that the longitudinal position of the annular electrode (654) corresponds to the longitudinal position of the second portion (670) and such that the annular electrode (654) is covered by the second portion (670). In some other configurations, the annular electrode (654) is longitudinally positioned between the planes (664, 666) such that the longitudinal position of the annular electrode (654) corresponds to the longitudinal position of the first portion (662) and such that the annular electrode (654) is covered by the first portion (662).

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

[0082] By having the first portion (662) or the second portion (670) of the profile defined by the arms (640, 644) of the end effector (630) cover the annular electrode (654), the blood flow around the annular electrode (654) can be relatively smooth, which can enable the annular 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 annular electrode (654) can affect the blood flow around the electrode (654) such that the turbulence of the flow can be less than if the annular electrode (654) were positioned elsewhere; and the acquisition of the potential from the blood by the annular electrode (654) can be more reliable than might be the case if the annular electrode (654) were positioned elsewhere. The reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (654) can be particularly enhanced when the annular electrode (654) is covered by the first portion (662).

[0083] Figure 12Another exemplary end effector (730) is shown that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary end effector (730) 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 arms (740) terminate distally at a joint (746); while the arms (744) terminate distally at a joint (752) proximal to the joint (746). In some configurations, each joint (746, 752) is simply formed by welding, adhering, or otherwise securing the distal ends of the corresponding arms (740, 744) together. The longitudinal intermediate 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), and the distal ends of the arms (740, 744) converge at the corresponding joints (746, 752). In this example, the arms (740, 744) are all positioned along a single flat plane. However, the arms (740, 744) are also flexible such that the arms (740, 744) can be laterally bent away from the central longitudinal axis (L-L) 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 laterally pressed against tissue. The arms (740, 744) can be elastically biased to return to Figure 12 the flat planar configuration shown. In some other configurations, portions of the arms (740, 744) are further offset from each other such that the arms (740, 744) are not positioned along a single flat plane.

[0084] The proximal ends of the arms (740, 744) extend along corresponding straight paths between a proximal plane (766) and an intermediate plane (764), the straight paths generally being parallel to each other and generally parallel to the longitudinal axis (L-L) of the catheter shaft (722). The most proximal regions of the arms (740, 744) between the planes (764, 766) together define a generally rectangular first 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 intermediate plane (764) to the distal plane (772). The arms (740, 744) thus extend outwardly along corresponding diverging paths through the second portion (770). As described above, distal to the distal plane (772), the arms (740, 744) extend along corresponding straight paths that are parallel to each other.

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

[0086] The end effector (730) also includes a central inner shaft (750) having a ring electrode (754). The ring electrode (754) is coaxially disposed about the inner shaft (750). In the present example, the ring electrode (754) is longitudinally positioned between planes (764, 772) such that the longitudinal position of the ring electrode (754) corresponds to the longitudinal position of the second portion (770) and such that the ring electrode (754) is covered by the second portion (770). In some other forms, the ring electrode (754) is longitudinally positioned between planes (764, 766) such that the longitudinal position of the ring electrode (754) corresponds to the longitudinal position of the first portion (762) and such that the ring electrode (754) is covered by the 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 the 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 an electrical 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 electrical 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 profile 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 obtain an electrical 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) such that the turbulence of the flow can be less than if the ring electrode (754) were positioned elsewhere; and obtaining an electrical potential from the blood through the ring electrode (754) can be more reliable than might be the case if the ring electrode (754) were positioned elsewhere. The reduction of blood flow turbulence and the increase in the sensing reliability of the ring electrode (754) can be particularly enhanced when the ring electrode (754) is covered by the first portion (762).

[0089] Figure 13 Shows another exemplary end effector (830) that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary 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); while the arm (844) forms a distal bend (852) proximal to the distal bend (846). The longitudinal intermediate 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 (L-L) 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 elastically biased to return to Figure 13 the flat planar configuration shown in. In some other configurations, portions of the arms (840, 844) are further offset from each other such that the arms (840, 844) are not positioned along a single flat plane.

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

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

[0092] The end effector (830) also includes a central inner shaft (850) having an annular electrode (854). The annular electrode (854) is coaxially disposed around the inner shaft (850). In this example, the annular electrode (854) is longitudinally positioned between planes (864, 872) such that the longitudinal position of the annular electrode (854) corresponds to the longitudinal position of the second portion (870), and such that the annular electrode (854) is masked by the second portion (870). In some other configurations, the annular electrode (854) is longitudinally positioned between planes (864, 866) such that the longitudinal position of the annular electrode (854) corresponds to the longitudinal position of the first portion (862), and such that the annular electrode (854) is masked by the first portion (862).

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

[0094] By masking the annular electrode (854) with the first portion (862) or the second portion (870) of the profile defined by the arms (840, 844) of the end effector (830), the blood flow around the annular electrode (854) can be relatively smooth, which can enable the annular electrode (854) to acquire the potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (840, 844) around the annular electrode (854) can affect the blood flow around the electrode (854) such that the turbulence of the flow can be less than if the annular electrode (854) were positioned elsewhere; and the acquisition of the potential from the blood by the annular electrode (854) can be more reliable than might be the case if the annular electrode (854) were positioned elsewhere. The reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (854) can be particularly enhanced when the annular electrode (854) is masked by the first portion (862).

[0095] Figure 14Another exemplary end effector (930) is shown that can be incorporated into a catheter assembly (100) to replace the end effector (130). The exemplary end effector (930) 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 respective distal bend (946) that is located at the same longitudinal distance from the distal end (924) of the catheter shaft (922). The arms (940, 944) overlap each other at an overlap point (980). The longitudinal intermediate regions of the arms (940, 944) 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 arm (940) is positioned along a first flat plane. In this example, the arm (944) is positioned along a second flat plane that is slightly offset from the first plane of the arm (940). The arms (940, 944) are also flexible such that the arms (940, 944) can be laterally bent away from the central longitudinal axis (L-L) along a path transverse to the plane defined by the arms (940, 944), thereby deforming the plane defined by the arms (940, 944). Such bending can occur when the end effector (930) is laterally pressed against tissue. The arms (940, 944) can be elastically biased to return to the Figure 14 flat planar configuration shown therein. In some other configurations, portions of the arms (940, 944) are further offset from each other such that the arms (940, 944) are not positioned along a single flat plane.

[0096] The proximal ends of the arms (940, 944) extend along respective straight paths between a proximal plane (966) and an intermediate plane (964), the straight paths generally being parallel to each other and generally parallel to the longitudinal axis (L-L) of the catheter shaft (922). The most 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 intermediate plane (964) to the distal plane (972). The arms (940, 944) thus extend outwardly along respective diverging paths through the second portion (970). As described above, distal to the distal plane (972), the arms (940, 944) extend along respective straight paths that are parallel to each other.

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

[0098] The end effector (930) also includes a central inner shaft (950) having an annular electrode (954). The annular electrode (954) is coaxially disposed about the inner shaft (950). In the present example, the annular electrode (954) is longitudinally positioned between planes (964, 972) such that the longitudinal position of the annular electrode (954) corresponds to the longitudinal position of the second portion (970) and such that the annular electrode (954) is covered by the second portion (970). In some other forms, the annular electrode (954) is longitudinally positioned between planes (964, 966) such that the longitudinal position of the annular electrode (954) corresponds to the longitudinal position of the first portion (962) and such that the annular electrode (954) is covered by the first portion (962).

[0099] In cases where the annular electrode (954) is covered by the first portion (962) or the second portion (970), the arms (940, 944) generally prevent tissue from contacting the annular electrode (954). However, the arms (940, 944) allow blood to flow through the end effector (930), thereby allowing the blood to contact the annular 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 an electrical potential at the contact area of the tissue surface (T), while the annular electrode (954) obtains a reference potential from the blood in which the annular electrode (954) is disposed. The processor of the console (12) can process the electrical 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 profile defined by the arms (940, 944) of the end effector (930) cover the annular electrode (954), the blood flow around the annular electrode (954) can be relatively smooth, which can enable the annular electrode (954) to obtain an electrical potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (940, 944) around the annular electrode (954) can affect the blood flow around the electrode (954) such that the turbulence of the flow can be less than if the annular electrode (954) were positioned elsewhere; and obtaining an electrical potential from the blood through the annular electrode (954) can be more reliable than might be the case if the annular electrode (954) were positioned elsewhere. The reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (954) can be particularly enhanced when the annular electrode (954) is covered by the first portion (962).

[0101] Figure 15 Illustrates another exemplary end effector (1030) that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary end effector (1030) 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 respective distal bend (1046) that is located at the same longitudinal distance from 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 intermediate 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 that is slightly offset from the first plane of the arm (1040). In this example, the arm (1046) is positioned along a third flat plane that is 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 be laterally bent away from the central longitudinal axis (L-L) 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 laterally pressed against tissue. The arms (1040, 1044, 1046) can be elastically biased to return to Figure 15 the flat planar configuration shown in. In some other configurations, portions of the arms (1040, 1044, 1046) are further offset from each other such that the arms (1040, 1044, 1046) are not positioned along a single flat plane.

[0103] The proximal ends of the arms (1040, 1044, 1046) extend along respective straight paths between a proximal plane (1066) and an intermediate plane (1064), the straight paths being generally parallel to each other and generally parallel to the longitudinal axis (L-L) of the catheter shaft (1022). The most proximal 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 intermediate plane (1064) to a distal plane (1072). The arms (1040, 1044, 1046) thus extend outwardly along respective diverging paths through the second portion (1070). As described above, distal to the distal plane (1072), the arms (1040, 1044, 1046) extend along respective straight paths that are parallel to each other.

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

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

[0106] When the annular 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 annular electrode (1054). However, the arms (1040, 1044, 1046) allow blood to flow through the end effector (1030), thereby allowing the blood to contact the annular 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) to obtain the potential at the contact area of the tissue surface (T), while the annular electrode (1054) obtains a reference potential from the blood in which the annular electrode (1054) is disposed. The processor of the console (12) can process the potentials from the electrodes (1042, 1054) to provide the electrocardiogram signal as described above.

[0107] By covering the annular electrode (1054) with the first portion (1062) or the second portion (1070) of the profile defined by the arms (1040, 1044, 1046) of the end effector (1030), the blood flow around the annular electrode (1054) can be relatively smooth, which can enable the annular electrode (1054) to obtain the potential from the blood in a relatively reliable manner. In other words, the arrangement of the arms (1040, 1044, 1046) around the annular electrode (1054) can affect the blood flow around the electrode (1054) such that the turbulence of the flow can be less than if the annular electrode (1054) were positioned elsewhere; and the potential obtained from the blood by the annular electrode (1054) is more reliable than might be the case if the annular electrode (1054) were positioned elsewhere. When the annular electrode (1054) is covered by the first portion (1062), the reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (1054) can be particularly enhanced.

[0108] Figure 16Shown is another exemplary end effector (1130) that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary end effector (1130) 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 intermediate 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 be laterally bent away from the central longitudinal axis (L-L) 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 laterally pressed against tissue. The arms (1140, 1444) can be elastically biased to return to the Figure 16 flat planar configuration shown. In some other configurations, portions of the arms (1140, 1444) are further offset from each other such that the arms (1140, 1444) are not positioned along a single flat plane.

[0109] The proximal ends of the arms (1140, 1444) extend along respective paths between a proximal plane (1164) and a distal plane (1172), the respective paths diverging outwardly from each other and from the longitudinal axis (L-L) of the catheter shaft (1122). The most proximal region of the arms (1140, 1444) between the planes (1164, 1172) thus together define a diverging portion (1170) of the profile of the end effector (1130). As described above, distally of the distal plane (1172), the arms (1140, 1444) extend along respective straight paths 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 configurations, the electrodes (1142) are arranged in pairs, such as the electrodes (146, 148) described above.

[0111] The end effector (1130) also includes a central inner shaft (1150) having an annular electrode (1154). The annular electrode (1154) is disposed coaxially about the inner shaft (1150). In the present example, the annular electrode (1154) is longitudinally positioned between planes (1164, 1172) such that the longitudinal position of the annular electrode (1154) corresponds to the longitudinal position of the diverging portion (1170) and such that the annular electrode (1154) is obscured by the diverging portion (1170).

[0112] In the case where the annular electrode (1154) is obscured by the diverging portion (1170), the arms (1140, 1444) generally prevent tissue from contacting the annular electrode (1154). However, the arms (1140, 1444) allow blood to flow through the end effector (1130), thereby allowing the blood to contact the annular electrode (1154). During use of the end effector (1130), one or more electrodes (1142) on the arms (1140, 1444) may contact the tissue surface (T), thereby acquiring the potential at the contact area of the tissue surface (T), while the annular electrode (1154) acquires a reference potential from the blood in which the annular electrode (1154) is disposed. A processor of the console (12) may 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 profile defined by the arms (1140, 1444) of the end effector (1130) obscure the annular electrode (1154), the blood flow around the annular electrode (1154) can be relatively smooth, which can enable the annular 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 annular electrode (1154) can affect the blood flow around the electrode (1154) such that the turbulence of the flow can be less than if the annular electrode (1154) were positioned elsewhere; and the acquisition of the potential from the blood by the annular electrode (1154) can be more reliable than might be the case if the annular electrode (1154) were positioned elsewhere. The reduction of blood flow turbulence and the increase in the sensing reliability of the annular electrode (1154) can be particularly enhanced when the annular electrode (1154) is obscured by the diverging portion (1170).

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

[0115] E. Exemplary Flush Ablation Tip End - Effector with an Integral Reference Electrode

[0116] Figure 17 An enlarged perspective view of an end effector (1230) having a tip (1240) that can be coupled to a catheter assembly (100) is shown. As a further example only, an end effector (1230) can be provided in place of the central axis (150) for the example shown in Figures 3 - 6 or in place of that for Figures 10 - 16The central inner shafts (550, 650, 750, 850, 950, 1050, 1150) of the examples shown in. The end effector (1230) of the example includes a flush tip (1240) positioned at the distal end (1224) of the catheter shaft (1222). The flush tip (1240) defines a hollow interior space and includes a main opening (1242) positioned adjacent an end (1252) of the flush tip (1240). A flush lumen (not shown) is provided for the main opening (1242), which extends along the length of the catheter shaft (1222) and is in fluid communication with the hollow interior space (1243) of the flush tip (1240). Flush fluid communicated from the flush lumen to the hollow interior space of the flush tip (1240) will be discharged through the main opening (1242).

[0117] While the reference electrode (1260) is shown proximal to the distal end of the flush tip (1240) in Figure 17 and on the outer surface of the tip (1240), it is within the scope of the present application to have a reference electrode (1260) positioned within the hollow interior space (1243) of the flush tip (1240). Wiring (1262) for the electrode (1260) may be embedded in the extruded tip or suitably mounted to the flush lumen. In a configuration 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 flush tip (1240) such that blood can enter the hollow interior space (1243) of the flush tip (1240) through the main opening (1242) and contact the reference electrode (1260). Alternatively, saline or some other fluid may 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). The reference electrode (1260) may obtain a reference potential from blood, saline, or other fluid passing through the hollow interior space (1243) of the flush tip (1240). During use of the end effector (1230), the reference electrode (1260) obtains a reference potential (e.g., through the opening (1242) or otherwise) from blood or saline etc. entering the hollow interior space (1243) of the flush tip (1240). The processor of the console (12) may process the potentials from the flush tip (1240) and the reference electrode (1260) to provide an electrocardiogram signal as described above.

[0118] When a reference electrode (1260) is used to obtain a reference potential from blood or saline that enters the hollow interior space (1243) of the irrigation tip (1240) through the opening (1242), the operator may stop communicating the irrigation fluid to the irrigation tip (1240), thereby allowing blood to enter the tip opening (1242). In some configurations, suction is briefly applied to the irrigation tip (1240) to draw blood through the side opening (1242) into the hollow interior space (1243) of the irrigation tip (1240). 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 communicated to the irrigation tip (1240) and a state in which suction is applied to the irrigation tip (1240). In configurations in which suction is provided through the irrigation tip (1240), such suction may be very brief - only long enough to draw a sufficient amount of blood through the side opening (1242) into the hollow interior space of the irrigation tip to contact the reference electrode (1260) for a sufficient duration to obtain a reference potential from the blood. With reference to the teachings herein, the various ways in which suction may be incorporated into the end effector (1230) will be apparent to those skilled in the art. Alternatively, the end effector (1230) may be entirely without suction capabilities.

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

[0120] Figure 18 Another exemplary end effector (1330) that may be incorporated into the catheter assembly (100) in place of the end effector (130) is shown. The exemplary end effector (1330) of this example includes an expandable assembly (1380) and a snare catheter (1332). The expandable assembly (1380) is positioned at the distal end (1324) of the catheter shaft (1322). The expandable assembly (1380) includes an expandable balloon (1382) (shown in an expanded state in Figure 18 and an array of angled-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 electrode (1394) is operable to apply RF energy to tissue to ablate the tissue. A hub member (1384) is secured to the distal end of the balloon (1382). The flexible circuit assemblies (1390) terminate distally at the hub member (1384).

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

[0122] An annular electrode (1360) is positioned on the hub member (1384) of the extensible assembly (1380). Although the annular electrode (1360) is shown positioned on the most distal portion of the hub member (1384), the annular electrode (1360) may alternatively be positioned at a proximal or longitudinally intermediate portion of the hub member (1384). The annular electrode (1360) is configured to contact blood surrounding the end effector (1330), thereby obtaining a reference potential from the blood. The annular 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 annular electrode (1360) is positioned within an interior region of the extensible assembly (1380). In this type of configuration, blood may enter the interior region of the extensible assembly (1380) through the central opening (1386) of the hub member (1384), thereby contacting the electrode (1360). In this type of configuration (and others), the annular electrode (1360) does not necessarily need to be formed as a ring, but may take any other suitable form.

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

[0124] As a further example only, in addition to having the above-described features and functions, the end effector (1330) can be constructed and operated in accordance with at least some of the teachings of U.S. Publication 2017 / 0312022, titled "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 a Depressed Proximal Reference Electrode

[0126] Figure 19 Another exemplary end effector (330) is shown that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary end effector (330) is configured and operable substantially similar to the above-described end effector (130) such that like components will not be described in further detail herein. Similar to the end effector (130), the exemplary end effector (330) includes a central shaft (350) having a distal opening (352) that is operable to dispense irrigation fluid. However, unlike the central shaft (150), the central shaft (350) of this example does not have an annular electrode (154). Instead, a reference electrode (362) is positioned at a location proximal to the arm (140) and the annular electrode (132) on the catheter shaft (122). The reference electrode (362) is positioned within 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) via the window (360) such that the reference electrode (362) can obtain a reference potential from the blood that contacts the reference electrode (362) via the window (360).

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

[0128] As a further example only, in addition to having the above-described features and functions, the end effector (330) can be constructed and operated in accordance with at least some of the teachings of: U.S. Publication 2016 / 0374753, titled "Catheter Having Closed Loop Array with In-Plane Linear Electrode Portion," published December 29, 2016, the disclosure of which is incorporated herein by reference; U.S. Publication 2018 / 0056038, titled "Catheter with Bipole Electrode Spacer and Related Methods," published March 1, 2018, the disclosure of which is incorporated herein by reference; U.S. Patent 9,907,480, titled "Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes," published March 6, 2018, the disclosure of which is incorporated herein by reference; U.S. Patent 9,949,656, titled "Catheter with Stacked Spine Electrode Assembly," published April 24, 2018, the disclosure of which is incorporated herein by reference; or U.S. Patent 9,820,664, titled "Catheter with High Density Electrode Spine Array," published November 21, 2017, the disclosure of which is incorporated herein by reference.

[0129] In addition, any of the other above-described catheter shafts (210, 522, 622, 722, 822, 922, 1022, 1122, 1222, 1322) can incorporate a recessed reference electrode (362) in a manner similar to that of the catheter shaft (122) described above with reference to Figure 19 the catheter shaft (122).

[0130] Such modifications can 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.

[0131] H. Exemplary Multi - Ray End - Effector with a Covered Proximal Reference Electrode

[0132] Figure 20 Another exemplary end effector (430) is shown that can be incorporated into the catheter assembly (100) to replace the end effector (130). The exemplary end effector (430) is configured and operable substantially similar to the above-described end effector (130) such that the same components will not be described in further detail herein. Similar to the end effector (130), the exemplary end effector (430) includes a central shaft (450) having a distal opening (452), and the distal opening (352) is operable to dispense irrigation fluid. However, unlike the central shaft (150), the central shaft (450) of this example does not have an annular electrode (154). Instead, a reference electrode (462) is positioned at a location proximal to the arm (140) and the annular electrode (132) on the catheter shaft (122). The reference electrode (462) is positioned below a cap-like member or tissue guard (460). The tissue guard (460) completely surrounds the reference electrode (462) and is configured to allow blood to contact the reference electrode (462) while preventing tissue from contacting the reference electrode (462). The tissue guard (460) is not conductive. By way of example only, the tissue guard (460) may be formed of a mesh material, a porous structure, a strip having a number of openings formed therein, or any other suitable type of construction that would be apparent to one of ordinary skill in the art in light of the teachings herein. The reference electrode (462) is operable to obtain a reference potential from the blood that contacts the reference electrode via the tissue guard (460).

[0133] During use of the end effector (430), one or more electrodes (146, 148) that contact the tissue surface (T) may obtain a potential at the contact area of the tissue surface (T), while the reference electrode (462) obtains a reference potential from the blood that contacts the reference electrode (462). 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.

[0134] As a further example, in addition to having the above-described features and functions, the end effector (430) can be constructed and operated in accordance with at least some of the teachings of: U.S. Publication 2016 / 0374753, published December 29, 2016, titled "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 March 1, 2018, titled "Catheter with Bipole Electrode Spacer and Related Methods", the disclosure of which is incorporated herein by reference; U.S. Patent 9,907,480, issued March 6, 2018, titled "Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes", the disclosure of which is incorporated herein by reference; U.S. Patent 9,949,656, issued April 24, 2018, titled "Catheter with Stacked Spine Electrode Assembly", the disclosure of which is incorporated herein by reference; or U.S. Patent 9,820,664, issued November 21, 2017, titled "Catheter with High Density Electrode Spine Array", the disclosure of which is incorporated herein by reference.

[0135] In addition, any of the other above-described catheter shafts (210, 522, 622, 722, 822, 922, 1022, 1122, 1222, 1322) can incorporate a reference electrode (462) with a tissue guard (460) in a manner similar to that of the catheter shaft (122) described above. Such modifications can be provided in addition to or in lieu of providing the electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) as described above. Figure 20

[0136] I. Dynamic Allocation of Reference Electrodes ​

[0137] 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 end effectors (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) can contact tissue, at least one other electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) may not contact the tissue. However, such non-tissue contact electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) can contact blood. Such non-tissue contact electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) can thus be used as reference electrodes, just like the electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) described above. In the example, the electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) can be omitted.

[0138] In some cases where an electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) is used as a reference electrode, a doctor (PH) may observe the signals acquired by the electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) to identify the electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) that are not in contact with tissue. Such observations can be made based on the signal readings presented on the 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 in contact with tissue, the doctor (PH) may mark the non-tissue contact electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) as reference electrodes. In some cases, the doctor (PH) may also mark specific tissue contact electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) for comparison with the reference electrode identified by the user. Then, the processor of the console (12) may process the potentials from the reference electrode identified by the user (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) and from the tissue contact electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342), and thereby provide the electrocardiogram signal as described above.

[0139] As an alternative to having a doctor (PH) identify the non-tissue contacting reference electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342), the processor (12) of the console can automatically identify the non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) and label the non-tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) as reference electrodes. By way of example only, the processor of the console (12) can 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) can have a lower impedance than the tissue contacting electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342).

[0140] As another merely illustrative example, the processor of the console (12) can examine the impedance between each of the dedicated reference electrodes (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) to identify which of the sensor electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) are contacting tissue and which of the sensor electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) are not contacting 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.

[0141] Based on the foregoing, each end effector (130, 200, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1330) described herein has at least one tissue contact electrode (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1240, 1342) and at least one non-tissue contact 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 the electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360), the non-tissue contact electrodes (154, 254, 554, 654, 754, 854, 954, 1054, 1154, 1260, 1360) can 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 the electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342), the non-tissue contact electrodes (146, 148, 232, 234, 542, 642, 742, 842, 942, 1042, 1142, 1342) accidentally do not contact tissue during a specific stage of the EP mapping procedure.

[0142] II. Exemplary Combinations

[0143] The following embodiments relate to various non-exhaustive ways in which the teachings herein can be combined or applied. It should be understood that the following embodiments are not intended to limit the scope of any claims that may be provided at any time in this patent application or subsequent filings of this patent application. No disclaimer is intended. The following embodiments are provided merely for illustrative purposes. It is contemplated that the various teachings herein can be arranged and applied in many other ways. It is also contemplated that some variations may omit certain features mentioned in the following embodiments. Accordingly, none of the aspects or features mentioned below should be considered decisive, unless otherwise specifically indicated as such by the inventors or their successors in interest at a later date. If any claims presented in this patent application or subsequent filings related to this patent application include additional features other than those mentioned below, these additional features should not be assumed to have been added for any reason related to patentability.

[0144] Example 1

[0145] An apparatus, 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 therebetween, the end effector sized to fit within an anatomical passageway in the cardiovascular system, the end effector including: (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 located proximal to the longitudinal midpoint of the end effector, the end effector configured to prevent the reference electrode from contacting tissue.

[0146] Example 2

[0147] The apparatus of claim 1, 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 middle 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.

[0148] Example 3

[0149] The apparatus of embodiment 2, wherein the reference electrode is positioned within the first portion of the profile.

[0150] Example 4

[0151] The apparatus of embodiment 2, wherein the first portion of the profile is generally cylindrical.

[0152] Example 5

[0153] The apparatus of embodiment 2, wherein the first portion of the profile is generally polygonal.

[0154] Example 6

[0155] The device according to any one or more of embodiments 2 to 5, the profile is generally substantially frustoconical.

[0156] Example 7

[0157] The device according to embodiment 6, the second profile is generally flared.

[0158] Example 8

[0159] The device according to embodiment 6, the second profile is generally pyramidal.

[0160] Example 9

[0161] The device according to any one or more of embodiments 2 to 8, the second profile diverges outward from the intermediate plane to the distal plane.

[0162] Example 10

[0163] The device according to any one or more of embodiments 1 to 9, the end effector is sized to fit within an anatomical passage in the human cardiovascular system.

[0164] Example 11

[0165] The device according to any one or more of embodiments 1 to 10, the end effector further includes a plurality of elongated ridges and a plurality of the sensor electrodes, the sensor electrodes being fixed to the ridges.

[0166] Example 12

[0167] The device according to embodiment 11, the ridges are configured to prevent tissue from contacting the reference electrode.

[0168] Example 13

[0169] The device according to any one or more of embodiments 11 to 12, the ridges are arranged parallel to each other and connected in the proximal region of the ridges to define a generally planar configuration.

[0170] Example 14

[0171] The device according to any one or more of embodiments 11 to 12, a first pair of ridges are connected in the proximal region to define a first plane, and a second pair of ridges are connected in the proximal region to define a second plane different from the first plane.

[0172] Example 15

[0173] The device according to any one or more of embodiments 11 to 14, wherein the shaft defines a longitudinal axis, and a portion of each of the ridges extends outwardly away from the longitudinal axis.

[0174] Example 16

[0175] The device according to any one or more of embodiments 11 to 15, wherein the shaft defines a longitudinal axis, and each of the ridges includes a respective free end oriented away from the longitudinal axis.

[0176] Example 17

[0177] The device according to any one or more of embodiments 11 to 16, wherein the shaft defines a longitudinal axis, and the end effector further includes a central axis extending along the longitudinal axis, the central axis being shorter than the ridges such that the reference electrode is positioned on the central axis and is partially covered by the ridges.

[0178] Example 18

[0179] The device according to embodiment 17, wherein the central axis of the end effector is further configured to dispense a flushing fluid.

[0180] Example 19

[0181] The device according to any one or more of embodiments 11 to 18, wherein the shaft defines a longitudinal axis, and the ridges are configured to bow outwardly and converge distally relative to the longitudinal axis to form a basket configuration.

[0182] Example 20

[0183] The device according to embodiment 19, wherein the reference electrode is positioned in an interior region of the basket configuration.

[0184] Example 21

[0185] The device according to any one or more of embodiments 1 to 20, wherein the shaft defines a longitudinal axis, and the reference electrode includes a ring coaxially positioned about the longitudinal axis.

[0186] Example 22

[0187] The device according to any one or more of embodiments 1 to 21, wherein the reference electrode is positioned proximally relative to the at least one sensor electrode.

[0188] Example 23

[0189] An apparatus, comprising: (a) a shaft extending along a longitudinal axis; (b) an end effector at a distal end of the shaft, the end effector sized to fit within an anatomical passage in the 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 including: (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 positioned within the cylindrical portion of the profile, the end effector configured to prevent the non-tissue contacting electrode from contacting tissue.

[0190] Example 24

[0191] The apparatus according to embodiment 23, wherein the apparatus can be reprocessed into a reusable apparatus for subsequent reuse.

[0192] Example 25

[0193] The apparatus according to embodiment 24, wherein the reprocessed apparatus is cleaned and disinfected with a solution for reuse in a subject.

[0194] Example 26

[0195] The apparatus according to embodiment 25, wherein the solution comprises a chemical selected from the group consisting of: peracetic acid at 3300 - 3800 ppm; glutaraldehyde at 2.65%; glutaraldehyde at 3.4% and isopropyl alcohol at 26%; glutaraldehyde at 3.5%; ortho-phthalaldehyde at 5.75%; ortho-phthalaldehyde at 0.55%; hypochlorite and hypochlorous acid at 650 - 675 ppm active free chlorine; glutaraldehyde at 1.12% and phenol / phenate at 1.93%; glutaraldehyde at 2.5%; glutaraldehyde at 3.2%; glutaraldehyde at 3%; hydrogen peroxide at 7.35% and peracetic acid at 0.23%; hydrogen peroxide at 1.0% and peracetic acid at 0.08%; glutaraldehyde at 2.4%; glutaraldehyde at 3.4%; hydrogen peroxide at 2.0%; ortho-phthalaldehyde at 0.60%; hypochlorous acid / hypochlorite with active free chlorine at 400 - 450 ppm; and combinations thereof.

[0196] Example 27

[0197] A method, comprising: (a) placing a first sensor electrode in contact with tissue in a patient's cardiovascular system; (b) positioning a reference electrode in contact with fluid in the patient's cardiovascular system without contacting 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) providing fluid communication through a lumen, the reference electrode being coaxially positioned around the lumen.

[0198] Example 28

[0199] The method according to embodiment 27, wherein the positioning step comprises preventing the reference electrode from contacting tissue with at least one flexible arm extending away from the longitudinal axis of the reference electrode.

[0200] Example 29

[0201] The method according to any one or more of embodiments 27 to 28, wherein the first sensor electrode is positioned on a flexible arm extending outward from the central longitudinal axis of the shaft, and the reference electrode is positioned around the central longitudinal axis of the shaft.

[0202] Example 30

[0203] The method according to any one or more of embodiments 27 to 29, further comprising: (a) placing a second sensor electrode in the patient's cardiovascular system 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 impedances, that the first sensor electrode is in contact with tissue and the second sensor electrode is not in contact with tissue.

[0204] Example 31

[0205] The method according to embodiment 30, wherein 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 tissue and the second sensor electrode is not in contact with tissue comprises 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.

[0206] Example 32

[0207] The method according to any one or more of embodiments 27 to 31, wherein the plotting step includes displaying a unipolar signal waveform having a reduction of the far-field signal in the range of 50% to 100% compared to a Wilson Central Terminal (WCT) reference signal.

[0208] Example 33

[0209] 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 a pair of ridges extending longitudinally from the distal end of the shaft to define a virtual volume around the tip member; and (d) a non-tissue contact electrode positioned adjacent to the opening of the tip member, the non-tissue contact electrode being configured to acquire a reference potential, and the tip member being configured to prevent the non-tissue contact electrode from contacting tissue.

[0210] Example 34

[0211] The device according to embodiment 33, wherein the non-tissue contact electrode is disposed inside the hollow interior space.

[0212] Example 35

[0213] The device according to embodiment 33, wherein the non-tissue contact electrode is disposed outside the hollow interior space.

[0214] Example 36

[0215] A device comprising: (a) a shaft having an outer surface defining a lateral window; and (b) an end effector at a distal end of the shaft, the end effector sized to fit within an anatomical passage in the cardiovascular system, the end effector including: (i) at least one sensor electrode configured to contact cardiovascular tissue and thereby acquire a potential, and (ii) a reference electrode configured to acquire a 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.

[0216] Example 37

[0217] The device according to embodiment 36, wherein the reference electrode is recessed relative to the outer surface of the shaft.

[0218] Example 38

[0219] An apparatus, comprising: (a) a shaft; (b) an end effector at a distal end of the shaft, the end effector sized to fit within an anatomical passage in the cardiovascular system, the end effector including at least one sensor electrode configured to contact cardiovascular tissue and thereby acquire an electrical potential; (c) an electrode covering member disposed on the shaft; and (d) a reference electrode configured to acquire an electrical potential from a fluid in contact with the reference electrode, the reference electrode positioned below the electrode covering member, the electrode covering member configured to allow blood to contact the reference electrode while preventing tissue from contacting the reference electrode.

[0220] Example 39

[0221] The apparatus according to embodiment 38, wherein the electrode covering member is porous.

[0222] Example 40

[0223] The apparatus according to any one or more of embodiments 38 to 39, wherein the shaft defines a longitudinal axis and the electrode covering member is coaxially positioned about the longitudinal axis.

[0224] III. Miscellaneous

[0225] 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 the device can then be placed in a radiation field that penetrates 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. Any other technique known in the art can also be used to sterilize the device, including but not limited to beta or gamma radiation, ethylene oxide, hydrogen peroxide, peracetic acid, and gas-phase sterilization (with or without gas plasma or vapor).

[0226] By way of example only, when one of the devices described herein is cleaned and disinfected before and / or after surgery, such cleaning and reprocessing can be carried out using a solution. As a further example only, such a solution can contain chemicals selected from the group consisting of: peracetic acid at 3300 - 3800 ppm; glutaraldehyde at 2.65%; glutaraldehyde at 3.4% with isopropyl alcohol at 26%; glutaraldehyde at 3.5%; ortho-phthalaldehyde at 5.75%; ortho-phthalaldehyde at 0.55%; hypochlorite and hypochlorous acid with 650 - 675 ppm of active free chlorine; glutaraldehyde at 1.12% with phenol / phenolate at 1.93%; glutaraldehyde at 2.5%; glutaraldehyde at 3.2%; glutaraldehyde at 3%; hydrogen peroxide at 7.35% with peracetic acid at 0.23%; hydrogen peroxide at 1.0% with peracetic acid at 0.08%; glutaraldehyde at 2.4%; glutaraldehyde at 3.4%; hydrogen peroxide at 2.0%; ortho-phthalaldehyde at 0.60%; hypochlorous acid / hypochlorite with active free chlorine at 400 - 450 ppm; and combinations thereof. As another exemplary example only, such a solution can contain chemicals selected from the group consisting of: peracetic acid at 3100 - 3400 ppm; glutaraldehyde at 3.4% with isopropyl alcohol at 20.1%; hydrogen peroxide at 2.0%; peracetic acid at at least 1820 mg / L; ortho-phthalaldehyde at 0.575%; ortho-phthalaldehyde at 0.60%; hypochlorite and hypochlorous acid with 650 - 675 ppm of active free chlorine; ortho-phthalaldehyde at 0.55%; hydrogen peroxide at 7.5%; glutaraldehyde at 2.6%; hypochlorite and hypochlorous acid with 400 - 450 ppm of active free chlorine; ortho-phthalaldehyde at 0.55%; and combinations thereof. The cleaning and / or disinfection procedures can be carried out in accordance with the United States Food and Drug Administration guidelines 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 entire disclosure of which is incorporated herein by reference.

[0227] By way of example only, when cleaning and disinfecting one of the devices described herein before and / or after a procedure, a disinfection system can be used for such cleaning and reprocessing, such as those described in the following patents: U.S. Patent No. 6,939,519, titled "Power System for Sterilization Systems Employing Low Frequency Plasma," published September 6, 2005, the disclosure of which is incorporated herein by reference in its entirety; U.S. Patent No. 6,852,279, titled "Sterilization with Temperature-ControL-Led Diffusion Path," published February 8, 2005, the disclosure of which is incorporated herein by reference; U.S. Patent No. 6,852,277, titled "Sterilization System Employing a Switching Module Adapter to Pulsate the Low Frequency Power Applied to a Plasma," published February 8, 2005, the disclosure of which is incorporated herein by reference; U.S. Patent No. 6,447,719, titled "Power System for Sterilization Systems Employing Low Frequency Plasma," published September 10, 2002, the disclosure of which is incorporated herein by reference. And U.S. Publication 2017 / 0252474, titled "Method of Sterilizing Medical Devices, Analyzing Biological Indicators, and Linking Medical Device Sterilization Equipment," published September 7, 2017, the entire disclosure of which is incorporated herein by reference. Some disinfection systems can use evaporated chemical disinfectants or chemical gases such as hydrogen peroxide, peracetic acid, ozone, chlorine dioxide, nitrogen dioxide, etc. to disinfect medical devices.Examples of such systems are described in the following patents: U.S. Patent No. 6,365,102, titled "Method of Enhanced Sterilization with Improved Material Compatibility," published on April 2, 2002, the entire disclosure of which is incorporated herein by reference; and U.S. Patent No. 6,325,972, titled "Apparatus and Process for Concentrating a Liquid Sterilant and Sterilizing Articles Therewith," published on December 4, 2001, the entire disclosure of which is incorporated herein by reference.

[0228] It should be understood that any example 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 example described herein may also include one or more of the various features disclosed in any one of the various references incorporated herein by reference.

[0229] 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. Accordingly, the above teachings, expressions, embodiments, examples, etc. should not be regarded as being isolated from one another. With reference to the teachings herein, various suitable ways in which the teachings herein may be combined will be apparent to those of ordinary skill in the art. Such modifications and variations are intended to be included within the scope of the claims.

[0230] It should be understood that any patent, patent publication, or other published material purported to be incorporated herein by reference, whether in its entirety or in part, is incorporated herein only to the extent that the incorporated material does not conflict with the existing definitions, statements, or other published material set forth in this disclosure. Accordingly, and to the extent necessary, the disclosure set forth herein explicitly supersedes any conflicting material incorporated herein by reference. Any material or portion thereof that is purported to be incorporated herein by reference but conflicts with the existing definitions, statements, or other published material set forth herein will be incorporated only to the extent that there is no conflict between the incorporated material and the existing published material.

[0231] In the case where various forms of the present invention have been shown and described, further improvements to the methods and systems described herein are achieved by appropriate modifications made by those of ordinary skill in the art without departing from the scope of the present invention. Several such possible modifications have been mentioned, and other modifications will be obvious to those skilled in the art. For example, the examples, forms, geometries, materials, dimensions, ratios, steps, etc. discussed above are exemplary and not necessary. Therefore, the scope of the present invention should be considered in light of the following claims and should be understood to be not limited to the details of the structures and operations shown and described in the specification and drawings.

Claims

1. An apparatus, 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 therebetween, the end effector sized to fit within an anatomical passageway in the cardiovascular system, the end effector comprising: (i) an expandable assembly formed by an array of angularly spaced ridges configured to transition the expandable assembly between a non-expanded state and an expanded state, and the ridges including 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 proximal to the longitudinal midpoint of the end effector, the end effector 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 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 an intermediate 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 within and masked by the second portion of the profile, the second portion being a flared frustoconical portion.

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

3. The apparatus of claim 1, wherein the second portion of the profile diverges outwardly from the intermediate plane to the distal plane.

4. The apparatus of claim 1, wherein the end effector is sized to fit within an anatomical passageway in the human cardiovascular system.

5. The apparatus of claim 1, wherein the ridges are configured to prevent tissue from contacting the reference electrode.

6. The apparatus of claim 1, wherein the shaft defines a longitudinal axis and a portion of each of the ridges extends outwardly away from the longitudinal axis.

7. The apparatus of claim 1, wherein the shaft defines a longitudinal axis and the end effector further includes a central axis extending along the longitudinal axis, the central axis being shorter than the ridges such that the reference electrode is positioned on the central axis and is partially masked by the ridges.

8. The apparatus of claim 7, wherein the central axis of the end effector is further configured to dispense a flushing fluid.

9. The device according to claim 1, wherein the shaft defines a longitudinal axis, and the ridges are configured to bend outwardly in an arcuate shape and converge distally relative to the longitudinal axis to form a basket configuration.

10. The device according to claim 9, wherein the reference electrode is positioned in an inner region of the basket configuration.

11. The device according to claim 1, wherein the shaft defines a longitudinal axis, and the reference electrode includes a ring positioned coaxially about the longitudinal axis.

12. The device according to claim 1, wherein the reference electrode is positioned proximally relative to the at least one sensor electrode.

13. The device according to claim 1, wherein the shaft includes an outer shaft, and a proximal end of the ridge is positioned in the outer shaft.

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