Patent Description:
In some procedures, a catheter with one or more 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 a cardiovascular structure adjacent to the heart (e.g., the pulmonary vein). The electrodes can be placed in contact with cardiac tissue or other vascular tissue and then electrically activated to ablate the contacted tissue. In some cases, the electrodes can be bipolar. In some other cases, a monopolar electrode may be used in conjunction with a ground pad that is in contact with the patient.

Examples of ablation catheters are described in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>, for each of which a copy is provided in the priority <CIT>.

Some catheter ablation procedures may be performed using electrophysiology (EP) mapping. Such EP mapping may include the use of sensing electrodes on a catheter (e.g., the same catheter that is used to perform the ablation). The sensing electrodes can be the same or different electrodes as those used to perform ablation. The sensing electrodes can monitor electrical signals within the cardiovascular system to pinpoint the location of aberrant conductive tissue sites that are responsible for the arrhythmia. Examples of an EP mapping system are described in <CIT> of which a copy is provided in the priority <CIT>. Examples of EP mapping catheters are described in <CIT>; <CIT>; and <CIT>, for each of which a copy is provided in the priority <CIT>.

EP mapping procedures may include the use of a reference electrode on a mapping catheter to sense electrical potentials in fluids near tissue. An example of such reference electrode is described in <CIT>, of which a copy is provided in the priority <CIT>.

In addition to using EP mapping, some catheter ablation procedures may be performed using an image guided surgery (IGS) system. The IGS system may enable the physician to visually track the location of the catheter within the patient, in relation to images of anatomical structures within the patient, in real time. Some systems may provide a combination of EP mapping and IGS functionalities, including the CARTO system by Biosense Webster, Inc. of Irvine, Calif. Examples of catheters that are configured for use with an IGS system are disclosed in <CIT>, of which a copy is provided in the priority <CIT>; and various other references that are cited herein and attached in the Appendix in the priority <CIT>.

The invention is defined by independent apparatus claim <NUM> and independent method claim <NUM>. Further embodiments are defined by dependent claims <NUM>-<NUM> and <NUM>-<NUM>. Examples presented herein generally include systems and methods which can contact electrodes to cardiac tissue while sensing electrical potential from fluids near the tissue. The electrodes in contact with the tissue can be carried by an end effector. The end effector sensors can be configured to ablate and/or sense electrical potentials from the cardiac tissue in which they are in contact. A reference electrode can be insulated by a shaft connected to the end effector so that the reference electrode can sense the electrical potentials from the fluids near the tissue while being prevented, by the shaft geometry, from contacting the cardiac tissue. The reference electrode can further serve as an extension of an irrigation tube positioned to irrigate the treatment area.

Other examples, features, aspects, embodiments, and advantages of the invention will become apparent to those skilled in the pertinent art from the following description, which includes by way of illustration, one of the best modes contemplated for carrying out the invention. As will be realized, the invention is capable of other different or equivalent aspects, all without departing from the invention.

Teachings, expressions, versions, examples, etc. described herein may be combined with other teachings, expressions, versions, examples, etc. that are described herein, including those examples provided in the references attached in the Appendix hereto. The following-described teachings, expressions, versions, examples, etc. should therefore not be viewed in isolation relative to each other. Various suitable ways in which the teachings herein may be combined are apparent to those skilled in the pertinent art in view of the teachings herein.

As used herein, the term "non-transitory computer-readable media" includes, but is not limited to, random access memory (RAM), read-only memory (ROM), electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible, physical medium which can be used to store computer readable information.

As used herein, the terms "tubular" and "tube" are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the tubular structure or system is generally illustrated as a substantially right cylindrical structure. However, the tubular system may have a tapered or curved outer surface without departing from the scope of the present invention.

As used herein, the term "wire" can include elongated solid core and hollow core structures. When used to refer to an electrical conductor, the term wire "wire" can include insulated, non-insulated, individual, bundled, and integrated circuit conductors.

<FIG> illustrates an example apparatus <NUM> having an elongated shaft <NUM>, a distal electrode assembly or end effector <NUM>, and a deflection control handle <NUM>. The apparatus <NUM> can have several design variations while including novel aspects illustrated herein. The apparatus <NUM> is presented for illustration purposes only and is not intended to be limiting. Details of the apparatus can be understood with reference to <CIT> to which the present application claims the benefits of priority.

The elongated shaft <NUM> has a proximal portion <NUM> in the shape of an elongated catheter body, an intermediate deflection section <NUM>, and distal portion 14A. The deflection control handle <NUM> is attached to the proximal end of the catheter body <NUM>. The distal portion 14A of the shaft is coupled to the end effector <NUM> via a connector tubing <NUM>. The connector tubing <NUM> is considered herein to be a distal extension of the elongated shaft such that the connector tubing <NUM> is considered a part of the elongated shaft <NUM>. The elongated shaft <NUM> forms a tubular catheter body sized and otherwise configured to traverse vasculature. The proximal portion <NUM> of the elongated shaft <NUM> can be manipulated (e.g. via the handle <NUM>) to position the distal portion 14A of the shaft <NUM> into a heart of a patient. The end effector <NUM> has a plurality of loop members <NUM>, <NUM>, <NUM> that overlap at a common distal vertex <NUM>. The loop members <NUM>, <NUM>, <NUM> can be joined at the distal vertex <NUM> by a mechanical linkage.

The end effector <NUM> is illustrated in an unconstrained configuration. When the device is unconstrained and aligned, the proximal portion <NUM>, intermediate section <NUM>, distal portion 14A, and end effector <NUM> are generally aligned along a longitudinal axis A-A. The elongated shaft <NUM> can define the longitudinal axis A-A of the apparatus <NUM>. The intermediate section <NUM> can be configured to bend to deflect the distal portion 14A and end effector <NUM> from the longitudinal axis A-A similar to as described in <CIT> (see <FIG> and <FIG>) incorporated by reference herein in its entirety and attached in the appendix hereto. Details of the apparatus can be understood with reference to <CIT>.

The end effector <NUM> can be collapsed (compressed toward the longitudinal axis A-A) to fit within a guiding sheath or catheter (not illustrated). The shaft <NUM> can be pushed distally to move the end effector <NUM> distally through the guiding sheath. The end effector <NUM> can be moved to exit a distal end of the guiding sheath via manipulation of the shaft <NUM> and/or control handle <NUM>. An example of a suitable guiding sheath for this purpose is the Preface Braided Guiding Sheath, commercially available from Biosense Webster, Inc. (Irvine, California, USA).

The end effector <NUM> has first, second and third loop members <NUM>, <NUM>, and <NUM>. Each loop member <NUM>, <NUM>, <NUM> has two spines 1A, 1B, 2A, 2B, 3A, 3B and a connector 1C, 2C, 3C that connects the two spines of the respective loop member <NUM>, <NUM>, <NUM>. Spines 1A, 1B of the first loop member <NUM> are connected by a first connector 1C; spines 2A, 2B of the second loop member <NUM> are connected by a second connector 2C; and spines 3A, 3B of the third loop member <NUM> are connected by a third connector 3C. Each loop member <NUM>, <NUM>, <NUM> further has a respective pair of ends affixed to the distal portion 14A of the elongated shaft <NUM> (e.g. affixed to the connector <NUM> which is an extension of the distal portion 14A of the elongated shaft <NUM>).

For each loop member <NUM>, <NUM>, <NUM> the spines 1A, 1B, 2A, 2B, 3A, 3B in the respective pair of spines can be substantially parallel to each other along a majority of their respective lengths when the end effector <NUM> is expanded in an unconstrained configuration as illustrated in <FIG>. Preferably, all spines in the end effector are parallel to each other along the majority of their respective lengths when the end effector <NUM> is in the unconstrained configuration. Even when all spines are parallel, the spines are not necessarily all coplanar. Details of the apparatus can be understood with reference to <CIT>.

Each spine 1A, 1B, 2A, 2B, 3A or 3B can have a length ranging between about <NUM> and <NUM>, preferably between about <NUM> and <NUM>, and more preferably about <NUM>. The parallel portions of each spine 1A, 1B, 2A, 2B, 3A, 3B can be spaced apart from each other by a distance ranging between about <NUM> and <NUM>, preferably between about <NUM> and <NUM>, and more preferably about <NUM>. Each spine 1A, 1A, 1B, 2A, 2B, 3A, 3B preferably carries at least eight electrodes per spine member. The end effector preferably includes six spines as illustrated. With eight electrodes on six spines, the end effector <NUM> includes forty-eight electrodes. The spine electrodes <NUM> can be positioned and otherwise configured to contact cardiovascular tissue. The spine electrodes <NUM> can be configured to receive electrical potentials from tissue that they are in contact with and/or ablate the tissue.

<FIG> is illustrated as including a distal electrode 38D and a proximal electrode 38P positioned near the distal portion 14A of the shaft <NUM>. The electrodes 38D and 38P can be configured to cooperate (e.g. by masking of a portion of one electrode and masking a different portion on the other electrode) to define a referential electrode (an electrode that is not in contact with tissues). As illustrated in greater detail in <FIG>, the apparatus <NUM> can include a reference electrode <NUM> positioned within the connector tubing <NUM> so that is it is prevented from contacting tissue by the connector tubing <NUM>. The reference electrode <NUM> can be used in addition to, or in place of one or both of the distal electrode 38D and the proximal electrode 38P illustrated in <FIG>. Due to the likelihood of the electrodes 38D and 38P coming into contact with tissues, it is preferable that reference electrode <NUM> is utilized by itself.

In some unipolar EP mapping techniques, it can be desirable to obtain a reference potential from blood near the tissue at which a tissue potential is being picked up. In other words, it may be desirable to place a first electrode in contact with tissue to thereby pick up an electrical potential from the tissue; and place a second electrode in electrical communication with blood near the contacted tissue to thereby pick up a reference electrical potential from the blood. The reference electrode can be in direct contact with the blood and/or be in electrical communication with the blood via other fluids such as irrigation fluid. The second (reference) electrode can be configured such that it is prevented from contacting tissue while maintaining electrical communication with blood. By having the second (reference) electrode avoid contact with tissue, the second (reference) electrode may avoid pickup of local tissue potentials that might otherwise compromise the reliability of the sensed reference potential. This configuration can provide benefits similar to those obtained using bipolar EP mapping devices and techniques, such as reduced noise and reduced far field signals, due to the location of the reference electrode being in the same heart chamber as tissue-contacting electrodes; while still maintaining features of a unipolar signal.

Referring again to <FIG>, it is expected that when the end effector <NUM> is pressed to tissue, one side of each of the reference electrodes 38D, 38P on the outside shaft <NUM> may contact tissue while the opposite side of each of the shaft reference electrodes 38D, 38P faces away from the tissue. The electrodes 38D, 38P can be masked with an electrical insulator on opposite sides such that when an unmasked side of one of the electrodes is against tissue, an unmasked side of the other electrode is facing away from the tissue; meaning, if one of the shaft reference electrodes 38D, 38P is in electrical contact with tissue, the other of the shaft electrodes 38D, 38P is insulated from the tissue by an electrically insulating mask.

Examples presented herein include a reference electrode <NUM> that has an electrically insulated outer surface such that electrically conductive portions of the reference electrode <NUM> are prevented from ever coming into contact with tissue. This eliminates the need for two electrodes (e.g. aforementioned shaft electrodes 38D, 38P) thereby reducing wires and bulk. The end effector <NUM> can be joined to the connector tubing <NUM> such that an outer surface area of the reference electrode <NUM> is partially exposed electrically and the exposed outer surface is positioned to prohibit the possibility that the exposed outer surface touches tissue during treatment.

One or more impedance sensing electrodes 38R can be configured to allow for location sensing via impedance location sensing technique, as described in <CIT>; <CIT>; and <CIT>, for each of which a copy is provided in the priority <CIT>.

<FIG> illustrate the intermediate section <NUM> and distal portion 14A of the shaft <NUM> of the apparatus in greater detail. <FIG> is a cross-sectional view, along the longitudinal axis A-A, of the elongated shaft <NUM> at the interface between the proximal portion <NUM> and intermediate section <NUM>. <FIG> is a cross-sectional view of the intermediate section <NUM> orthogonal to the longitudinal axis A-A.

As illustrated in <FIG>, the catheter body <NUM> can be an elongated tubular construction having a single axial passage or central lumen <NUM>. The central lumen <NUM> can be sized to allow an irrigation tube <NUM> to pass therethrough. The catheter body <NUM> is flexible, i.e., bendable, but substantially non-compressible along its length. The catheter body <NUM> can be of any suitable construction and made of any suitable material. In some embodiments, the catheter body <NUM> has an outer wall <NUM> made of polyurethane or PEBAX. The outer wall <NUM> may include an imbedded braided mesh of stainless steel or the like to increase torsional stiffness of the catheter body <NUM> so that, when the control handle <NUM> is rotated, the intermediate section <NUM> will rotate in a corresponding manner.

The outer diameter of the catheter body <NUM> is preferably no more than about <NUM> French, more preferably about <NUM> French. The thickness of the outer wall <NUM> is thin enough so that the central lumen <NUM> can accommodate at least one puller wire, one or more lead wires, and any other desired wires, cables or tubes (e.g. irrigation tube <NUM>). If desired, the inner surface of the outer wall <NUM> is lined with a stiffening tube <NUM> to provide improved torsional stability. In some embodiments, the outer wall <NUM> has an outer diameter of from about <NUM> inch to about <NUM> inch (from about <NUM> to about <NUM>) and an inner diameter of from about <NUM> inch to about <NUM> inch (from about <NUM> to about <NUM>).

As illustrated particularly in <FIG>, the intermediate section <NUM> can include a shorter section of tubing <NUM> having multiple lumens, for example, four off-axis lumens <NUM>, <NUM>, <NUM>, <NUM> and a central lumen <NUM>. The first lumen <NUM> carries a plurality of lead wires <NUM> for ring electrodes <NUM> carried on the spines 1A, 1B, 2A, 2B, 3A, 3B. The second lumen <NUM> carries a first puller wire <NUM>. The third lumen <NUM> carries a cable <NUM> for an electromagnetic position sensor <NUM> and lead wires 40D and 40P for distal and proximal ring electrodes 38D and 38P carried on the catheter proximally of the end effector <NUM> and/or the reference electrode <NUM> within the tubing <NUM>.

Electromagnetic location sensing technique is described in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>, for each of which a copy is provided in the priority <CIT>. The magnetic location sensor <NUM> can be utilized with impedance sensing electrode 38R in a hybrid magnetic and impedance position sensing technique known as ACL described in <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>, for each of which a copy is provided in the priority <CIT>.

The fourth lumen <NUM> (for example, diametrically opposite of the second lumen <NUM> as illustrated) carries a second puller wire <NUM>. The fifth, central lumen <NUM> carries the irrigation tube <NUM>.

The tubing <NUM> is made of a suitable non-toxic material that is preferably more flexible than the catheter body <NUM>. One suitable material for the tubing <NUM> is braided polyurethane, i.e., polyurethane with an embedded mesh of braided stainless steel or the like. The size of each lumen is sufficient to house the lead wires, puller wires, the cable and any other components.

The useful length of the catheter shaft <NUM>, i.e., that portion of the apparatus <NUM> that can be inserted into the body excluding the end effector <NUM>, can vary as desired. Preferably the useful length ranges from about <NUM> to about <NUM>. The length of the intermediate section <NUM> (measured from the connection to the catheter body <NUM> to the distal end of the shaft <NUM>) is a relatively smaller portion of the useful length, and preferably ranges from about <NUM> to about <NUM>, more preferably from about <NUM> to about <NUM>.

Catheter body proximal portion <NUM> can be attached to the intermediate section <NUM> similar to as shown and described in <FIG> of <CIT>, of which a copy is provided in the priority <CIT>.

If desired, a spacer (not shown) can be located within the catheter body <NUM> between the distal end of the stiffening tube (if provided) and the proximal end of the intermediate section <NUM>. The spacer can provide a transition in flexibility at the junction of the catheter body <NUM> and intermediate section <NUM>, which can allow this junction to bend smoothly without folding or kinking. A catheter having such a spacer is described in <CIT>, of which a copy is provided in the priority <CIT>.

The distal portion 14A of the shaft <NUM> can be substantially contiguous with the intermediate section <NUM> such that the intermediate section comprises the distal portion 14A; the distal portion being distinguished from the intermediate section <NUM> by the positioning of one or more (optional) ring electrodes 38R. As referred to herein, the distal portion 14A of the shaft <NUM> can therefore correspond to a distal portion of the intermediate section <NUM>. The connector tubing <NUM> can also be considered a distal extension of the shaft <NUM> so that it is understood that the connector tubing <NUM> is included in the distal portion 14A of the shaft.

<FIG> illustrate the end effector and distal portion of the shaft <NUM> (connector tubing <NUM>) in various orientations where the connector tubing is illustrated as translucent and all components within the connector tubing are made invisible with the exception of the reference electrode <NUM> and the irrigation tube <NUM> for the purposes of illustration. The connector tubing <NUM> can further house ends of support frames which extend through the loop members <NUM>, <NUM>, <NUM> to secure the loop members <NUM>, <NUM>, <NUM> to the shaft <NUM> similar to the apparatus described and illustrated in <CIT>. The connector tubing <NUM> can further house electrical conductors <NUM>, 40D, 40P, <NUM> such as those illustrated in <FIG>.

<FIG> illustrate the connector tubing in various orientations with the end effector <NUM> made invisible for the purpose of illustration.

A Cartesian x, y, z axis is illustrated in each of the <FIG> to illustrate relative orientations for each of the illustrations.

Referring collectively to <FIG>, the reference electrode <NUM> can include a tubular inner surface 5B and a tubular outer surface 5C. The inner tubular surface 5B can be electrically conductive. The inner surface 5B can be positioned and otherwise configured so that fluids near cardiovascular tissue (e.g. blood and/or irrigation fluid) are in contact with the inner surface 5B when the spine electrodes <NUM> are in contact with cardiovascular tissue. The inner surface 5B can receive electrical potentials from these fluids so that the electrical potentials received by the reference electrode act as a referential signal for the electrical potentials of the electrodes <NUM> carried by the spines 1A, 1B, 2A, 2B, 3A, 3B.

The reference electrode <NUM> can be disposed in the elongated shaft <NUM> (being disposed in the connector <NUM> which is a distal extension of the shaft <NUM>) such that the electrode does not protrude beyond the elongated shaft <NUM>. The outer surface 5C of the reference electrode <NUM> can be substantially electrically isolated from the electrical potentials of the fluids. The connector <NUM> of the shaft <NUM> can serve as an insulating cover which electrically isolates the outer surface 5C. The reference electrode <NUM> can have a distal end 5A that is approximately coaxial or coplanar with a distal end 46A of the connector <NUM> (which corresponds to a distal end of the shaft <NUM>). The term "coplanar" as used in relation to the reference electrode distal end 5A and the distal end 46A means that a plane may intersect both 5A and 46A so that both ends (5A and 46A) are on the same plane. In the example shown in <FIG>, a virtual plane (not shown) intersects surface 5C and 46A orthogonally so that both ends 5A and 46A are on the same plane. The term "coaxial" indicates that the longitudinal axis of connector <NUM> and the longitudinal axis of the reference electrode <NUM> are coincident with each other. The connector <NUM> can be capable of contacting the cardiovascular tissue while the spine electrodes are in contact with the cardiovascular tissue and while the reference electrode <NUM> is electrically insulated, by the connector, from the cardiovascular tissue as illustrated in greater detail in <FIG>.

The irrigation tube can be in fluidic communication with the inner surface 5B of the reference electrode <NUM>. Fluids can flow through the irrigation tube and out of the shaft <NUM> through the reference electrode <NUM> so that the reference electrode <NUM> serves as a distal extension of the irrigation tube <NUM>.

As illustrated in <FIG>, the end effector <NUM> can have an unconstrained configuration aligned with a longitudinal axis A-A of the apparatus <NUM> and a flattened or paddle shaped geometry in the unconstrained configuration. The end effector <NUM> can have a height H and a width W measured as indicated in <FIG>, the height H being significantly smaller than the width W. Further, compared to the dimensions of the connector <NUM>, the height H of the end effector <NUM> can be about equal to, or smaller than, a diameter D1 of a tubular outer surface of the connector <NUM>, where the diameter D1 is measured as indicated in <FIG>. The width W of the end effector <NUM> can be substantially greater than the diameter D1 of the connector <NUM>. The end effector can have a length L measured as indicated in <FIG> that is greater still than the width W.

Having the paddle shape, the spine electrodes <NUM> are all positioned in a distal direction in relation to the reference electrode <NUM>. When pressed to a surface, the spine electrodes <NUM> and references electrode <NUM> can roughly maintain their relative positions to each other compared to the unconstrained configuration. This results in the spine electrodes <NUM> being positioned to preferably be distributed in a radially asymmetric pattern on the cardiovascular tissue in relation to the reference electrode's position when the plurality of spine electrodes <NUM> are in contact with the cardiovascular tissue. In other words, the reference electrode <NUM> is positioned to one side of the collection of spine electrodes <NUM> when the electrodes <NUM>, <NUM> are in operation during a treatment. This in contrast to other end effector geometries, such as illustrated in <FIG> where spines of the end effector extend radially from the reference electrode <NUM> so that it is possible to preferably distribute spine electrodes in a radially symmetric pattern on the cardiovascular tissue in relation to the reference electrode's position. Paddle shaped end effectors such as illustrated in <FIG> also include spine electrodes positioned to be distributed in a radially asymmetric pattern on tissue in relation to the reference electrode's position.

The spine electrodes <NUM> can be positioned to form a rectangular grid when the spine electrodes <NUM> are contact with the cardiovascular tissue. Alternatively, the spine electrodes <NUM> can be positioned to form a non-rectangular grid; e.g. a circular, triangular, or other such shape.

As illustrated in greater detail in <FIG> and <FIG>, the irrigation tube <NUM> can be positioned within a lumen of the reference <NUM> electrode. The apparatus <NUM> can further include an irrigation tube cover <NUM> to act as a fluid impermeable seal between the reference electrode <NUM> and the irrigation tube <NUM>.

The distal end 5A of the electrode <NUM> is approximately co-planar with the distal end 46A of the connector <NUM> or even recessed (<FIG>) so that the electrode <NUM> does not protrude from the shaft <NUM> (e.g., <FIG>). An insulating material <NUM> can be provided between the outer surface 5C of the electrode <NUM> and the inside surface 46B of connector <NUM>. In one embodiment, material <NUM> can be a polymer such as for example, polyurethane. Configured as such, insulating material <NUM> insulates the outer surface 5C of the electrode <NUM> to prevent the outer surface 5C from coming into electrical contact with tissue during use. At the same time, however, inner surface 5C of reference electrode <NUM> is able to have electrical and physical contact with the biological fluid in the organ (e.g., blood) in order to receive or record the electrical signals propagated in the fluid. It is noted that irrigation line <NUM> can also work in reverse, by aspirating or sucking blood from the organ into the irrigation line <NUM>. This allows for the reference electrode <NUM> to receive or sense electrical signals (via wiring 5D or electrical trace) in the blood significantly better because the blood is pulled into irrigation tube <NUM> allowing immersion of the conductive inner surface 5C with the blood pulled into irrigation tube <NUM>.

As illustrated in greater detail in <FIG>, the connector <NUM> can include a collar <NUM> forming the outer surface 46A of the connector <NUM> and an insert <NUM> positioned in the collar <NUM>. The insert <NUM> can include openings <NUM> shaped to receive ends of the loop members <NUM>, <NUM>, <NUM> and a central lumen <NUM> sized to house the reference electrode <NUM>. A polymer can be flowed into the collar <NUM> and insert <NUM> to help secure the loop members <NUM>, <NUM>, <NUM> and reference electrode <NUM> in the connector <NUM>.

<FIG> are illustrations of the end effector <NUM> being pressed to a surface S. The end effector <NUM> can deflect at an angle θ relative to the longitudinal axis A-A to position the spine electrodes <NUM> to the surface S. The surface S is illustrated as planar; however, the surface can be curved. For instance, the surface S can have curvature consistent with intracardiac tissue surfaces.

<FIG> illustrates the end effector <NUM> having a portion of spine electrodes <NUM> pressed to the surface S and another portion of the spine electrodes <NUM> above the surface S, not in contact with the surface S.

<FIG> illustrates the connector <NUM> positioned above the surface S with all spine electrodes <NUM> in contact with the surface. The end effector <NUM> is deflected an angle θ relative to the longitudinal axis A-A that is nearly <NUM>°. At such an angle, were the reference electrode <NUM> positioned such that it protruded from the shaft <NUM>, depending on the length of protrusion and the distance between the distal end 46A of the connector <NUM> and the surface S, the reference electrode <NUM> may come into contact with the surface S. If the reference electrode <NUM> were to make electrical contact with the surface S, it can reduce the effectiveness of the reference electrode's ability to sense electrical potentials that can serve as reference electrical potentials. In other words, were the reference electrode <NUM> to come into electrical contact with tissue, it may not function as a reliable reference electrode. Positioning the reference electrode <NUM> so that it does not protrude from the connector <NUM> of the shaft <NUM> prevents the reference electrode <NUM> from contacting the surface S even when the end effector <NUM> is deflected at an angle of about <NUM>° from the longitudinal axis A-A of the shaft <NUM>.

<FIG> illustrates the connector <NUM> in contact with the surface S with all spine electrodes <NUM> in contact with the surface S. The end effector <NUM> is deflected at an acute angle θ relative to the longitudinal axis A-A. Having the connector <NUM> very near to the surface S and at a non-zero angle to the surface S, were the reference electrode <NUM> positioned such that it protruded from the shaft <NUM>, depending on the length of protrusion and the angle θ, the reference electrode <NUM> may come into contact with the surface S. Positioning the reference electrode <NUM> so that it does not protrude from the connector <NUM> of the shaft <NUM> prevents the reference electrode <NUM> from contacting the surface S even when the connector <NUM> is in contact with the surface S and angled toward the surface S.

<FIG> are illustrations of an alternative reference electrode configuration. The figures include a z axis to provide orientation relative to <FIG>.

<FIG> is an illustration of a cross section of an alternative reference electrode configuration. Only the connector <NUM>, reference electrode <NUM>, and irrigation tube <NUM> are illustrated for the purposes of illustration. The apparatus <NUM> can include additional components not illustrated such as conductors and mechanical connection to the end effector <NUM> described elsewhere herein, including the Appendix. The irrigation tube <NUM> can be positioned around the outer surface 5C of the reference electrode <NUM>. The transition from the irrigation tube <NUM> to the reference electrode <NUM> can be sealed to cause the reference electrode <NUM> to be an extension of the irrigation tube <NUM>. In addition, or as an alternative to the outer surface 5C being electrically insulated by the connector <NUM>, the outer surface 5C of the reference electrode <NUM> can be electrically insulated by a portion of the irrigation tube <NUM> positioned over the outer surface 5C of the reference electrode <NUM>. In some configurations, such as illustrated, the irrigation tube <NUM> and reference electrode <NUM> can protrude from the elongated shaft so that the irrigation tube <NUM> prevents the outer surface 5C of the reference electrode <NUM> from coming into contact with tissue. For instance, the distal end 5A of the reference electrode <NUM> can be positioned in the irrigation tube <NUM> so that the reference electrode <NUM> does not protrude from the irrigation tube <NUM>.

<FIG> is an illustration of a cross section of another alternative reference electrode configuration. In the alternative configuration, the reference electrode does not serve as an extension to the irrigation tube <NUM> but rather has an electrically conductive distal surface at its distal end 5A that is configured to receive electrical potentials from fluids that act as a reference signal for the electrical potentials from the spine electrodes <NUM>. The electrically conductive surface at the distal end 5A of the reference electrode <NUM> is approximately coplanar or coaxial to the distal end 46A of the connector <NUM>. Only the connector <NUM> and reference electrode <NUM> are illustrated for the purposes of illustration. The apparatus <NUM> can include additional components not illustrated such as conductors and mechanical connection to the end effector <NUM> described elsewhere herein, including in the Appendix.

<FIG> is an illustration of an exemplary medical procedure and associated components of a cardiac electrophysiology (EP) mapping catheter system that may utilize the apparatus <NUM> (also referred to as a catheter assembly). A physician PH is illustrated grasping the handle <NUM> of the apparatus, with the end effector <NUM> (not shown in <FIG>) disposed in a patient PA to perform EP mapping in or near the heart H of the patient PA. The apparatus <NUM> is coupled with a guidance and drive system <NUM> via a cable <NUM>. The apparatus <NUM> can optionally be coupled with a fluid source <NUM> via a fluid conduit <NUM>. A set of field generators <NUM> are positioned underneath the patient PA and are coupled with guidance and drive system <NUM> via another cable <NUM>. Field generators <NUM> are also optional.

The guidance and drive system <NUM> can include a console <NUM> and a display <NUM>. The console <NUM> can include a first driver module <NUM> and a second driver module <NUM>. The first driver module <NUM> can be coupled with the apparatus via a cable <NUM>. In some variations, the first driver module <NUM> is operable to receive EP mapping signals obtained via spine electrodes <NUM> of end effector <NUM>. The console <NUM> can include a processor (not shown) that processes such EP mapping signals and thereby provides EP mapping. In addition, or in the alternative, the first driver module <NUM> may be operable to provide RF power to the spine electrodes <NUM> of end effector <NUM> to thereby ablate tissue. In some versions, the first driver module <NUM> is also operable to receive position indicative signals from a position sensor in end effector <NUM>. In such versions, the processor of console <NUM> is also operable to process the position indicative signals from the position sensor to thereby determine the position of the end effector <NUM> within the patient PA.

The guidance and drive system <NUM> can further include non-transitory computer readable medium with instructions thereon to case the drive system <NUM> to perform functionality described herein and/or as are known related to use of similar equipment. In some examples, the non-transitory computer readable memory can be in communication with the first driver module <NUM> (e.g. by virtue of being in communication with a processor of the first driver module <NUM> and/or the processor of the console <NUM>). The non-transitory computer readable medium can include instructions thereon that when executed by the first driver module <NUM> cause the first driver module <NUM> to receive EP mapping signals from the spine electrodes <NUM> and a reference signal from the reference electrode <NUM>.

The second driver module <NUM> is coupled with field generators <NUM> via a cable <NUM>. The second driver module <NUM> is operable to activate field generators <NUM> to generate an alternating magnetic field around the heart H of the patient PA. For instance, the field generators <NUM> may include coils that generate alternating magnetic fields in a predetermined working volume that contains the heart H.

Some versions of the apparatus <NUM> include a position sense near or within the end effector <NUM> that is operable to generate signals that are indicative of the position and orientation of end effector <NUM> within the patient PA. Each position sensor may include a wire coil or a plurality of wire coils (e.g., three orthogonal coils) that are configured to generate electrical signals in response to the presence of an alternating electromagnetic field generated by field generators <NUM>. Other components and techniques that may be used to generate real-time position data associated with end effector <NUM> may include wireless triangulation, acoustic tracking, optical tracking, inertial tracking, and the like. By way of example only, position sensing may be provided in accordance with at least some of the teachings of <CIT>, of which a copy is provided in the priority <CIT>.

Alternatively, apparatus <NUM> may lack a position sensor near the end effector <NUM>.

The display <NUM> is coupled with the processor of console <NUM> and is operable to render images of patient anatomy. Such images may be based on a set of preoperatively or intraoperatively obtained images (e.g., a CT or MRI scan, <NUM>-D map, etc.). The views of patient anatomy provided through the display <NUM> may also change dynamically based on signals from the position sensor near the end effector <NUM>.

The processor of the console <NUM> may also drive the display <NUM> to superimpose the current location of end effector <NUM> on the images of the patient's anatomy, such as by superimposing an illuminated dot, a crosshair, a graphical representation of end effector <NUM>, or some other form of visual indication.

The fluid source <NUM> can include a bag containing saline or some other suitable irrigation fluid. The conduit <NUM> can include a flexible tube that is further coupled with a pump <NUM>, which is operable to selectively drive fluid from the fluid source <NUM> to the irrigation tube <NUM> of the apparatus <NUM>. In some variations, such as including a reference electrode <NUM> as configured in <FIG>, the conduit <NUM>, fluid source <NUM>, and pump <NUM> are omitted entirely.

<FIG> are illustrations of alternative end effectors 100a-f having loop members and including an intralumenal reference electrode <NUM> described elsewhere herein. The end effectors include a reference electrode that does not protrude from the shaft <NUM> and therefore is not visible in the views of the figures. The end effectors can otherwise be configured similarly to the end effectors illustrated in <CIT> (see Figures 8A through 8F), <CIT>, and <CIT> (see Figures <NUM> through <NUM>), for each of which a copy is provided in the priority <CIT>.

<FIG> is an illustration of an alternative end effector <NUM> having a ray geometry and including an intralumenal reference electrode according to aspects of the present invention. The end effector includes a reference electrode <NUM> that does not extend beyond the shaft <NUM>. The end effector can otherwise be configured similarly to the end effectors illustrated in <CIT> (see <FIG>), <CIT> (see <FIG>), and <CIT> (see <FIG>, <NUM>, and <NUM>). It is noted that the reference electrode as described and illustrated herein can be utilized with an end effector having a basket configuration whereby each of the spines expand outward and converges towards a distal end is within the scope of the invention. One example of such basket configuration is shown exemplarily in <CIT>.

Claim 1:
An apparatus comprising:
an elongated shaft (<NUM>) comprising a proximal portion and a distal portion, the elongated shaft configured to be manipulated at the proximal portion to position the distal portion into a heart of a patient;
an end effector (<NUM>) disposed proximate the distal portion of the elongated shaft and comprising spines (1A, 1B, 2A, 2B, 3A, 3B) each carrying at least one spine electrode (<NUM>) configured to contact cardiovascular tissue and receive electrical potentials from the tissue; and
a reference electrode (<NUM>) comprising an inner surface (5B) and an outer surface (5C) disposed about a longitudinal axis (A-A) extending along the elongated shaft, the reference electrode being disposed in the elongated shaft such that the electrode does not protrude beyond the elongated shaft such that the elongated shaft prevents the reference electrode from contacting the tissue,
the inner surface of the reference electrode being configured to receive electrical potentials from fluids that act as a referential signal for the electrical potentials of the at least one spine electrode.