Patent Description:
Procedures for treating arrhythmia include surgically disrupting the origin of the signals causing the arrhythmia, as well as disrupting the conducting pathway for such signals. More recently, it has been found that by mapping the electrical properties of the endocardium and the heart volume, and selectively ablating cardiac tissue by application of energy, it is possible to cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions.

In this two-step procedure, which includes mapping followed by ablation, electrical activity at points in the heart is typically sensed and measured by advancing a catheter containing one or more electrical sensors into the heart and acquiring data at multiple points. These data are then utilized to select the target areas at which ablation is to be performed.

For greater mapping resolution, it is desirable for a mapping catheter to provide high-density signal maps through the use of several electrodes sensing electrical activity of tissue in an area on the order of a square centimeter. For mapping within an atria or a ventricle (for example, an apex of a ventricle), it is desirable for a catheter to collect larger amounts of data signals within shorter time spans. It is also desirable for such a catheter to be adaptable to different tissue surfaces, for example, flat, curved, irregular or nonplanar surface tissue and be collapsible for atraumatic advancement and withdrawal through a patient's vasculature. In <CIT>, there is described a catheter with an end effector having densely arrayed electrodes on three loops which are arrayed in various planar configurations when the end effector is unconstrained.

Embodiments of the invention are defined by the dependent claims. Although methods are not explicit in the language of the claims, they are nevertheless useful for understanding the invention. Example apparatuses disclosed herein are generally usable with catheter-based systems to measure or provide electrical signals within the heart and surrounding vasculature. Example apparatuses generally include an end effector having loop members with electrodes thereon. The end effector can include features which provide improved and/or alternative diagnostic or treatment options compared to existing end effectors. Such features can include three loop members that are non-coplanar when expanded unconstrained that become contiguous to a planar surface when the spines are deflected against the surface, a mechanical linkage that joins three loop members of the end effector, electrodes having surface treatment to enhance surface roughness of the electrodes, twisted pair electrode wires, a bonded spine cover, and/or any combination thereof.

An example method can include one or more of the following steps presented in no particular order. A first loop member, a second loop member, and a third loop member can each respectively be shaped to each form a respective loop. A respective pair of ends of each of the first loop member, the second loop member, and the third loop member can be coupled to a distal portion of an elongated shaft. The first loop member, the second loop member, and the third loop member can be overlapped at a common distal vertex distal to the distal portion of the elongated shaft such that when the first, second, and third loop members are unconstrained, a majority of the first loop member is non-coplanar with a majority of at least one of the second loop member and the third loop member. The majority of the first loop member, the majority of the second loop member, and the majority of the third loop member can be pressed in contact with a planar surface via manipulation of the elongated shaft. The first, second and third loop members can be placed into contact with a planar surface to align the majority of the first loop member, the majority of the second loop member, and the majority of the third loop member with the planar surface.

The method can further include positioning the first loop member, second loop member, third loop member, and distal portion of the elongated shaft within an intravascular catheter (or guiding sheath) while a proximal portion of the elongated shaft extends proximally from the intravascular catheter.

The method can further include moving the first loop member, second loop member, and third loop member out of a distal end of the catheter via manipulation of the proximal portion of the elongated shaft.

The method can further include pressing the majority of the first loop member, the majority of the second loop member, and the majority of the third loop member in contact with the planar surface via manipulation of the proximal portion of the elongated shaft.

The method can further include shaping a first support frame to define a first looped path such that the first support frame comprises a cross sectional shape orthogonal to the first looped path that varies along the first looped path. The method can further include positioning the first support frame in the first loop member. The method can further include shaping a second support frame to define a second looped path such that the second support frame comprises a cross sectional shape orthogonal to the second looped path that varies along the second looped path. The method can further include positioning the second support frame in the second loop member. The method can further include shaping a third support frame to define a third looped path such that the third support frame comprises a cross sectional shape orthogonal to the third looped path that varies along the third looped path. The method can further include positioning the third support frame in the third loop member.

The method can further include affixing the first, second, and third support frames to the distal portion of the elongated shaft at each end of the respective pair of ends of the first loop member, the second loop member, and the third loop member.

The method can further include engaging a serrated edge of each of the first, second, and third support frames to the distal portion of the elongated shaft.

The method can further include positioning the first support frame, the second support frame, and the third support frame such that the first looped path defines a first plane intersecting at least one of a second plane defined by the second looped path and a third plane defined by the third looped path.

The method can further include shaping a first pair of parallel segments in the first support frame, a second pair of parallel segments in the second support frame, and a third pair of parallel segments in the third support frame. The method can further include moving a majority of a length of each segment of the first pair of parallel segments, the second pair of parallel segments, and the third pair of parallel segments into alignment parallel to the planar surface via manipulation of the elongated shaft.

The method can further include shaping a first connecting segment extending between the first pair of parallel segments, a second connecting segment extending between the second pair of parallel segments, and a third connecting segment extending between the third pair of parallel segments.

The method can further include mechanically binding the three loop members at the distal vertex.

The method can further include forming a clip having two ends and a partially wrapped shape having an opening sized to receive the first, second, and third loop members. The method can further include moving the first, second, and third loop members through the opening into the partially wrapped shape. The method can further include moving the two ends of the clip to collapse the opening. The method can further include confining the first, second, the third loop members at the distal vertex with the clip.

As an alternative to confining the first, second, and third loop members with the clip, the method can include confining the first, second, the third loop members at the distal vertex within an opening of an alternative mechanical linkage having a contiguous perimeter.

As another alternative, the method can include forming another alternative mechanical linkage having a rectangular or ovular shape having a first opening, a second opening, and a third opening. The method can further include positioning the first loop member in the first opening, the second loop member in the second opening, and the third loop member in the third opening. The method can further include linking the first, second, and third loop members at the distal vertex with the mechanical linkage. The method can further include forming the first opening to have a substantially circular shape. The method can further include forming at least one of the second opening and the third opening to have an oblong shape.

As another alternative, the method can include forming another alternative mechanical linkage having a cylindrical shape with a first passageway therethrough, a second passageway therethrough, and a third passageway therethrough. The method can further include positioning the first loop member in the first passageway, the second loop member in the second passageway, and the third loop member in the third passageway. The method can further include linking the first, second, and third loop members at the distal vertex with the mechanical linkage. The method can further include surrounding each of the first loop member, the second loop member, and the third loop member with a respective tubular housing. The method can further include positioning each of the respective tubular housings respectively through the first passageway, the second passageway, and the third passageway. As an alternative to positioning the respective tubular housings through the first, second, and third passageways, the method can include surrounding each of the first loop member, the second loop member, and the third loop member with a respective tubular housing excepting at least a respective portion of the first loop member, the second loop member, and the third loop member where the respective loop member extends through the respective passageway.

As another alternative to confining the first, second, and third loop members with the clip, the method can include confining the first, second, the third loop members at the distal vertex within an opening of a mechanical linkage including a tapered ring having an annular opening through which the first, second, the third loop members extend and a height tapering across a diameter of annular opening.

The method can further include affixing a plurality of electrodes to the three loop members. The method can further include abrading at least a portion of a surface of each electrode of the plurality of electrodes. The method can further include swaging each electrode of the plurality of electrodes.

The method can further include electrically connecting wires to electrodes carried by the first, second, and third loop members. The method can further include bundling the wires within the first, second, and third loop members.

The method can further include at least partially surrounding the first support frame in an inner tubular housing. The method can further include positioning a plurality of electrical conductors adjacent to the first support frame and outside of the inner tubular housing. The method can further include at least partially surrounding the inner tubular housing and the plurality of electrical conductors with an outer tubular housing. The method can further include bonding the outer tubular housing to the inner tubular housing.

As an alternative to the steps including the inner tubular housing and the outer tubular housing, the method can include positioning the first support frame within a first lumen of a tubular housing having at least two lumens therethrough. The method can further include positioning a plurality of electrical conductors within a second lumen of the tubular housing, the second lumen being separate from the first lumen. The method can further include positioning an irrigation tube in the second lumen.

As another alternative to the steps including the inner tubular housing and the outer tubular housing, the method can further include positioning the first support frame within a first lumen of a tubular housing having at least three lumens therethrough. The method can further include positioning a plurality of electrical conductors within a second lumen of the tubular housing, the second lumen being separate from the first lumen. The method can further include positioning an irrigation tube within a third lumen of the tubular housing, the third lumen being separate from the first lumen and the second lumen.

Another example method can include the following steps presented in no particular order. A distal portion of an elongated shaft and an end effector extending distally from the distal portion can be moved through a catheter (or guiding sheath) to the heart. The end effector can be moved from a distal end of the catheter via manipulation of a proximal portion of the elongated shaft. The end effector can be expanded to an unconstrained configuration distal to the distal end of the catheter such that the end effector has three loop members overlapping in three layers at a common distal vertex in the unconstrained configuration. The end effector can be pressed into cardiac tissue via manipulation of the proximal portion of the elongated shaft. A majority of each of the loop members can be conformed to the cardiac tissue as a result of pressing the end effector into cardiac tissue.

The method can further include expanding the end effector in the unconstrained configuration such that the majority of each of the three loop members are non-coplanar with at least one of the other three loop members.

The method can further include bending three support frames, each extending through a respective loop member of the three loop members and affixed to the distal portion of the elongated shaft, as a result of pressing the end effector into cardiac tissue.

The method can further include positioning the three support frames such that each respective support frame has a respective pair of parallel segments. The method can further include aligning a majority of each length of each segment of each of the respective pair of parallel segments parallel to the cardiac tissue as a result of pressing the end effector into cardiac tissue. The method can further include bending the three support frames on either side of the majority of each length of each segment of each of the respective pair of parallel segments as a result of pressing the end effector into cardiac tissue.

The method can further include bending the three support frames along thinner segments of the support frame, the thinner segments having a cross sectional area measuring less than a cross sectional area of the majority of each length of each segment of each of the respective pair of parallel segments.

The method can further include positioning the three support frames such that each respective support frame includes a respective connecting segment extending between the respective pair of parallel segments and overlapping, at the distal vertex, the respective connecting segment of each of the other respective support frames.

The method can further include maintaining the overlapping of the three loop members at the distal vertex with a mechanical linkage positioned at the distal vertex.

The method can further include receiving electrical signals having signals representing noise of less than <NUM> mV from electrodes positioned on the end effector and in contact with the cardiac tissue.

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 is 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, as defined by the appended claims.

Any one or more of the teachings, expressions, versions, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, versions, examples, etc. that are described herein. 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 will be readily apparent to those skilled in the pertinent art in view of the teachings herein.

<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 shaft <NUM> is preferably a tubular member. <FIG> and illustrations of orthogonal side plan views of a variation of the apparatus <NUM> illustrated in <FIG>. The apparatus <NUM> can have several design variations to while including novel aspects illustrated herein. The apparatus <NUM> is presented for illustration purposes only and is not intended to be limiting.

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 elongated shaft <NUM> forms a tubular catheter body sized and otherwise configured to traverse vasculature. The end effector <NUM> has a plurality of loop members <NUM>, <NUM>, <NUM> that overlap at a common distal vertex and are joined at the distal vertex with a mechanical linkage <NUM>.

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 L-L. The intermediate section <NUM> can be configured to bend to deflect the distal portion 14A and end effector <NUM> from the longitudinal axis L-L.

The end effector <NUM> can be collapsed (compressed toward the longitudinal axis L-L) 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 a first loop member <NUM> are connected by a first connector 1C; spines 2A, 2B of a second loop member <NUM> are connected by a second connector 2C; and spines 3A, 3B of a third loop member <NUM> are connected by a third connector 3C. The connectors 1C, 2C, 3C are preferably arcuate members as illustrated.

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 as described in greater detail elsewhere herein, for instance in relation to <FIG>.

Each spine 1A, 1B, 2A, 2B, 3A or 3B can have a length ranging between about <NUM> and <NUM>, preferably 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 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.

A distal electrode 38D and a proximal electrode 38P are 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). 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>, of which a copy is provided in the priority <CIT>.

<FIG> illustrates 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 L-L, 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 L-L. <FIG> is an isometric view of the distal portion 14A and connector tubing <NUM> with certain components illustrated as transparent.

As illustrated in <FIG>, the catheter body <NUM> can be an elongated tubular construction having a single axial passage or central lumen <NUM>. 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. 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> and <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>. Electromagnetic location sensing technique is described in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT> 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>, 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 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, can vary as desired. Preferably the useful length ranges from about <NUM> to about <NUM>. The length of the intermediate section <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> 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>.

As illustrated in <FIG>, the distal portion 14A of the shaft <NUM> is coupled to the end effector <NUM> with a connector tubing <NUM>. The connector tubing <NUM> includes an insert for connection of loop members <NUM>, <NUM>, <NUM> to provide electrical connection through the intermediate portion <NUM> of the catheter body. The connector tubing <NUM> can be affixed to the distal portion 14A of the catheter by glue or the like.

The connector tubing <NUM> can be shaped to house various components such as an electromagnetic position sensor, a puller wire anchor, ring electrodes 38D, 38P, etc. The connector tubing <NUM> can include a central lumen <NUM> to house various components. An outer circumferential notch <NUM> (<FIG>) in the distal end of the tubing <NUM> that receives the inner surface of the proximal end of the connector tubing <NUM> can be used to attach the connector tubing <NUM> and the intermediate section <NUM> (distal portion 14A of shaft <NUM>). The intermediate section <NUM> and connector tubing <NUM> are attached by glue or the like.

The connector tubing <NUM> can house various components, including an electromagnetic position sensor <NUM>, and a distal anchor bar for a first puller wire <NUM> and another anchor bar 51B for a second puller wire <NUM>. Only the anchor 51B for second puller wire <NUM> is visible in <FIG>. The anchor bar for the first puller wire can be configured as a mirror image to the illustrated puller wire anchor bar 51B. Carried on the outer surface of the tubing <NUM> near the distal end of the intermediate deflection section <NUM> (distal portion 14A of the shaft <NUM>), a distal ring electrode 38D is connected to lead wire formed in the side wall of the tubing <NUM>. The distal end of the lead wire is welded or otherwise attached to the distal ring electrode 38D as known in the art.

<FIG> are illustrations of a front and side view of the end effector <NUM>. The three loop members <NUM>, <NUM>, <NUM> overlap at a common distal vertex <NUM> along the longitudinal axis L-L. Each of the loop members <NUM>, <NUM>, <NUM>, respectively include proximal end segments 1D, 2D, 3D, 1E, 2E, 3E affixed to the distal portion 14A of the elongated shaft <NUM> of the apparatus <NUM>.

The end effector <NUM> is in an unconstrained configuration as illustrated in <FIG>. As better visualized in the side view of <FIG>, when the end effector is unconstrained, the loop members <NUM>, <NUM>, <NUM> are not coplanar with each other. <FIG> also illustrates an orthogonal axis O-O orthogonal to the longitudinal axis L-L and approximately orthogonal to the front view of the end effector <NUM>.

<FIG> are illustrations depicting orientation of loop members of the end effector. <FIG> are cross sectional views of the end effector <NUM> and as indicated in <FIG> is a view of the end effector <NUM> looking proximally from a distal end of the end effector <NUM> as indicated in <FIG>.

<FIG> illustrates a cross sectional view through the connector <NUM>. The connector <NUM> includes a tubular insert <NUM> that has its center coinciding with the longitudinal axis L-L. Orthogonal planes P4 and P5 are in alignment with the longitudinal axis to define four quadrants in the insert <NUM>. A parallel reference plane P5 is approximately parallel to the front view of the end effector <NUM> illustrated in <FIG>. An orthogonal reference plane P4 is approximately orthogonal to the parallel reference plane P5 and approximately parallel to the orthogonal axis O-O. Apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the insert <NUM> are sized, positioned, and otherwise configured for insertion of respective end segments 1D, 2D, 3D, 1E, 2E, 3E. Openings <NUM>, <NUM> are disposed on orthogonal plane P4 for insertion of puller wires or electrical wires as well as any other components to and from the end effector <NUM>. Components which traverse the apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and openings <NUM>, <NUM> are not illustrated in <FIG> for the purposes of illustration.

With this arrangement of apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, loop members <NUM>, <NUM> and <NUM> are arrayed in a non-coplanar unconstrained arrangement, shown in the sectional view of <FIG> (as viewed from the proximal end), whereby loop <NUM> defines a plane P3 (demarcated by spines 3A and 3B with connector 3C) that intersects orthogonal plane P4 with loop <NUM> having a plane P1 (demarcated by spines 1A and 1B with connector 1C) that intersects both orthogonal planes P4 and P5 and loop <NUM> having a plane P2 (demarcated by spines 2A and 2B and connector 2C) that intersects orthogonal plane P4 and is substantially parallel to orthogonal plane P5. <FIG> is a view of the distal end of the end effector looking proximally. In particular, loop <NUM> (defined by spines 1A, 1B and connector 1C) is arrayed to define plane P1 that is contiguous to or extend through spines 1A, 1B and loop 1C whereas spines 2A, 2B and connector 2C of loop <NUM> are arrayed to define a plane P2 that intersects with plane P1. Spines 3A, 3B and connector 3C of loop <NUM> are arrayed to define a plane P3 that intersects with both planes P1 and P2. The planes P1, P2, and P3 defined by the respective loops <NUM>, <NUM> and <NUM> are configured so that the loops P1, P2 and P3 are not contiguous to or arrayed such that a common plane passes through the loops. Thus, planes P1, P2 and P3 are non-parallel and intersects each other. It is noted that the longitudinal axis L-L may be contiguous to the second plane P2. In alternative embodiment, longitudinal axis L-L may be disposed in between a region bounded by planes P1, P2 and P3.

<FIG> are one example of non-coplanar arrangement of loop members <NUM>, <NUM>, <NUM> in an end effector. There are numerous possible arrangements non-coplanar arrangements of loop members which can result in an end effector having the general appearance of the illustrated end effector <NUM>.

<FIG> is an illustration depicting electrode spacing and dimensions on the end effector. The electrodes <NUM> can include one or more pairs of closely-spaced bipolar microelectrodes 37A, 37B which are configured to pick up electrocardiogram signals from tissue. In the present example, the microelectrodes 37A, 37B of a pair has a separation space gap distance (Lg) therebetween of approximately <NUM> to <NUM> microns and preferably no greater than about <NUM> microns. Each electrode 37A, 37B has an electrode area (Ae) and electrode length (L). The electrode length can be from about <NUM> to about <NUM>. Each spine electrode <NUM> preferably has a length of <NUM> to <NUM>. The electrodes <NUM> as illustrated are cylindrical such that the electrode area is calculated as a produce of the circumference (C) and length (L) of the electrode. The spine has a diameter (D).

Additionally, or alternatively, the microelectrodes 37A, 37B need not completely circumscribe the respective loop <NUM>, <NUM>, <NUM>; in which case the microelectrodes 37A, 37B can have a rectangular shape that is rectilinear or arced having a width (W) such that the electrode area (Ae) is a produce of the electrode length (L) and width (W), the width being the arc length when the rectangular shape is arced. In examples where the electrode pair configurations are in shapes other than rectilinear, rectangular, or cylindrical, a conversion factor CF may be used to determine the appropriate gap distance between the electrodes based on the known area of either one of the pair of electrodes. The conversion factor CF may range from about <NUM> to <NUM> in the inverse of the same root dimensional unit as the planar area of an electrode. In one example, where the planar area of one electrode is about <NUM> squared-mm, the smallest gap distance (Lg) along the longitudinal axis extending through both electrodes can be determined by applying the conversion factor CF (in the inverse of the same root dimensional unit of the area or mm) to arrive at a gap distance Lg of about <NUM> microns. In another example where the area of one electrode is <NUM> squared-mm, the conversion factor CF (in the inverse of the same root dimensional unit or mm-<NUM>) can be <NUM>-<NUM> or less, giving the range of the smallest gap distance Lg from about <NUM> microns to about <NUM> microns. Regardless of the shape of the electrodes, a preferred conversion factor CF is about <NUM> (in the inverse of the same root dimensional unit for the electrode area).

<FIG> is another illustration of the end effector <NUM> including a mechanical linkage <NUM>. At least one pair of closely-spaced bipolar microelectrodes 37A, 37B is provided on each spine 1A, 2A, 3A, 1B, 2B, 3B in the present example. More particularly, each spine 1A, 2A, 3A, 1B, 2B, 3B carries four pairs of bipolar microelectrodes <NUM> corresponding to eight microelectrodes <NUM> per spine. This number may be varied as desired. <FIG> also illustrates a clip <NUM> coupling connectors 1C, 2C, 3C together in a single connection point. The clip <NUM> functions to maintain a spatially fixed arrangement between the loops <NUM>, <NUM>, <NUM> at the common distal vertex.

<FIG> are illustrations of views of the end effector pressed to a planar surface S. In the illustrated example, the loop members <NUM>, <NUM>, <NUM> can be pressed to the planar surface S via manipulation of the shaft <NUM> of the device. More specifically, when the end effector <NUM> is positioned within a patient, manipulation of the catheter body <NUM> and the control handle <NUM> can be used to position the end effector <NUM> against a surface within a wall of an internal cavity of the patient such internal walls of the heart and/or blood vessels. When the end effector <NUM> is positioned against the planar surface S, a majority of each length of each spine 1A, 2A, 3A, 1B, 2B, 3B can become contiguous and aligned to the planar surface. Further, when the end effector <NUM> is positioned against the planar surface S, a majority of each length of each spine 1A, 2A, 3A, 1B, 2B, 3B can become aligned with a majority of each length of the other spines. The surface S need not necessarily be planar in order for the spines 1A, 2A, 3A, 1B, 2B, 3B to become contiguous and aligned to the surface. The end effector <NUM> may be able to conform to a curved surface, for instance.

As illustrated in <FIG>, when the majority of each spine 1A, 2A, 3A, 1B, 2B, 3B is pressed to the surface S, the connecting segments 1C, 2C, 3C can be stacked on top of the surface S at the distal vertex at the linkage <NUM>. A first connecting segment 1C nearest to the surface S can be separated from the surface S by the linkage <NUM>. A second connecting segment 3C stacked onto the first connecting segment 1C can be separated from the surface S by the linkage <NUM> and the first connecting segment 1C. A third connecting segment 2C can be separated from the surface S by the linkage <NUM> and the first and second connecting segments 1C, 3C. Therefore, at least a portion of each connecting segment 1C, 2C, 3C can be separated from the planar surface S when the majority of each spine 1A, 2A, 3A, 1B, 2B, 3B is pressed to the planar surface. Alternatively, the linkage <NUM> can be inset into the first connecting segment 1C such that the first connecting segment is substantially contiguous to the planar surface S. In that case, only the second and third connecting segments 3C, 2C are separated from the planar surface S at the distal vertex.

Proximal segments 1D, 2D, 3D, 1E, 2E, 3E of the loop members <NUM>, <NUM>, <NUM> can be bent such that at least a portion of each of the proximal segments curves away from the surface S.

When the majority of each spine 1A, 2A, 3A, 1B, 2B, 3B is pressed to the surface S, at least some of the electrodes <NUM> on each spine can be in contact with the surface S. In some examples, every electrode <NUM> on each spine can be in contact with the surface <NUM>.

When the majority of each spine 1A, 2A, 3A, 1B, 2B, 3B is pressed to the surface S, the majority of each respective length of each loop member can become contiguous to the surface S, where the respective length of each loop member includes the length of the respective loop member's spines 1A, 2A, 3A, 1B, 2B, 3B, connectors 1C, 2C, 3C, and proximal segments 1D, 2D, 3D, 1E, 2E, 3E (distal to the connector tubing <NUM>).

<FIG> is an illustration of the intermediate section <NUM> of the shaft of the catheter deflected at approximately <NUM>°. The end effector <NUM> has a first side 100A and a second side 100B. This allows the user to place first side 100A (or 100B) against the tissue surface, with at least the intermediate section <NUM> (if not also a distal portion of the catheter body <NUM>) generally perpendicular to the tissue surface, and actuates the control handle to deflect the intermediate deflection section <NUM> to arrive at various deflections or radii of curvature (e.g., arrows D1 and D2) such that the second side 100B deflects back toward the catheter body <NUM>. Being positioned as such may allow dragging of the second side 100B of the end effector <NUM> including the loop members <NUM>, <NUM>, <NUM> across the tissue surface as the intermediate section <NUM> is deflecting. The intermediate section can be deflected via manipulation of the puller wires <NUM>, <NUM> illustrated in <FIG>. The puller wires <NUM>, <NUM> can be two separate tensile members or parts of a single tensile member. In some examples, the puller wires <NUM>, <NUM> can be actuated for bi-directional deflection of the intermediate section <NUM>. The puller wires <NUM>, <NUM> can be actuated by mechanisms in the control handle <NUM> that are responsive to a thumb control knob or a deflection control knob <NUM>. Suitable control handles are disclosed in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT> and <CIT>, of which a copy is provided in the priority <CIT>.

Details of the construction of puller wires including anchor via T-bars 51B (see <FIG>) at the intermediate section <NUM>, as known in the art and described in, for example, <CIT> and <CIT>, of which a copy is provided in the priority <CIT>. The puller wires <NUM> and <NUM> can be made of any suitable metal, such as stainless steel or Nitinol. The puller wires <NUM>, <NUM> are preferably coated with TEFLON or the like. The coating imparts lubricity to the puller wires. The puller wires preferably have a diameter ranging from about <NUM> to about <NUM> inch (from about <NUM> to about <NUM>).

<FIG> are illustrations of a support frame assembly <NUM> of the end effector <NUM>. <FIG> and <FIG> illustrate the support frame assembly <NUM> in an unconstrained configuration. <FIG> illustrate the support frame assembly <NUM> being pressed to a surface S. When the end effector <NUM> is assembled, the loop members <NUM>, <NUM>, <NUM> each includes a respective support frame <NUM>, <NUM>, <NUM>. The support frame assembly <NUM> extends into the connector tubing <NUM> to mechanically affix the loop members <NUM>, <NUM>, <NUM> to the shaft <NUM>. The support frames <NUM>, <NUM>, <NUM> provide structural integrity for the loop members <NUM>, <NUM>, <NUM>. The support frames <NUM>, <NUM>, <NUM> can include plastic or metal cut-off sheets, plastic or metal round wire, plastic or metal square wire, or other suitable biocompatible material. In the preferred embodiments, the support frame are made from shape memory material such as, for example, nitinol. For the purposes of testing and illustration, the support frame assembly <NUM> is joined at a distal vertex with mechanical linkage <NUM>. In the assembled end effector <NUM>, the support frames <NUM>, <NUM>, <NUM> can be assembled by virtue of a mechanical linkage affixed to an outer housing of the loop members <NUM>, <NUM>, <NUM> or a direct linkage between the support frames <NUM>, <NUM>, <NUM>.

When the end effector is unconstrained, each of the respective support frames <NUM>, <NUM>, <NUM> defines a respective looped path of its respective loop member <NUM>, <NUM>, <NUM> as illustrated in <FIG>. Each support frame <NUM>, <NUM>, <NUM> includes respective parallel segments 81A, 82A, 83A, 81B, 82B, 83B that extend through corresponding spines 1A, 2A, 3A, 1B, 2B, 3B of the end effector <NUM>. Each support frame <NUM>, <NUM>, <NUM> includes respective proximal segments 81D, 82D, 83D, 81E, 82E, 83E that extend through corresponding proximal segments 1D, 2D, 3D, 1E, 2E, 3E of respective loop members <NUM>, <NUM>, <NUM>. The proximal segments 81D, 82D, 83D, 81E, 82E, 83E extend into the connector tubing <NUM> to join the end effector <NUM> to the shaft <NUM>. Each support frame <NUM>, <NUM>, <NUM> includes a respective connecting segments 81C, 82C, 83C that extends between the respective pair of parallel segments 81A, 82A, 83A, 81B, 82B, 83B and through the respective connecting segment 1C, 2C, 3C of the respective loop member <NUM>, <NUM>, <NUM>.

When the end effector is unconstrained, at least one of the parallel segments 81A, 82A, 83A, 81B, 82B, 83B is not aligned in a common plane with other parallel segments. Said another way, at least one of the looped paths is non-coplanar with one or both of the other looped paths. The pair of parallel segments 81A, 82A, 83A, 81B, 82B, 83B for each support frame <NUM>, <NUM>, <NUM> can define a plane for the pair's respective support frame <NUM>, <NUM>, <NUM>. The support members <NUM>, <NUM>, <NUM> can generally align to define three planes P3, P4, P5 as illustrated in <FIG> when the end effector <NUM> is in the unconstrained configuration.

When the loop member <NUM>, <NUM>, <NUM> is pressed to a surface S as in the sequence of illustrations of <FIG>, a majority of the respective length of each segment in each of the respective pairs of parallel segments can become approximately coplanar with a majority of the respective length of each of the other segments in each of the respective pairs of parallel segments. The support members <NUM> can become aligned with the surface S as the loop members <NUM>, <NUM>, <NUM> are pressed into the surface S as illustrated in <FIG>. When the surface S is planar, the parallel segments 81A, 82A, 83A, 81B, 82B, 83B become coplanar with each other along a majority of their respective lengths.

Each support frame <NUM>, <NUM>, <NUM> can include knuckles to promote conformance of the loop members <NUM>, <NUM>, <NUM> to the surface S. The knuckles can be spaced uniformly or non-uniformly along the looped path of a respective support member <NUM>, <NUM>, <NUM>. Knuckle features can include thinned out sections of the material of the support members <NUM>, <NUM>, <NUM>. Additionally, or alternatively, the knuckle features can include hinge mechanisms.

<FIG> are illustrations of example support frames that vary in cross section along a respective looped path of each support frame. Each of the support frames <NUM> can respectively have a cross sectional shape that varies along the individual support frame's looped path, where the cross sectional shape is taken from a cross section orthogonal to the direction of the looped path. <FIG> illustrate two different example support frame assemblies 80a, 80b. Each of the example support frame assemblies 80a, 80b having regions I-I with a cross sectional area configured to resist deflection and regions II-II configured to facilitate deflection. The regions I-I configured to resist deflection can have a larger cross sectional area compared to the regions II-II configured to facilitate deflection. Alternatively, the regions I-I configured to resist deflection can be flattened to resist deflection in the direction of long sides of the cross section while having a similar cross section to non-flattened, or less flattened regions II-II. That is, in <FIG>, the thin section are intended to promote sheath retraction (lower force for the frame to collapse) while in <FIG>, the distal II-II section is intended still for frame collapsing, but the proximal II-II section (knuckles) are intended to promote deflection with respect to the longitudinal axis L-L.

<FIG> is another illustration of an example support frame assembly 80c of the end effector <NUM>. <FIG> are illustrations of cross sectional areas of the example support frame as indicated in <FIG>. <FIG> are illustrations of example transitions schemes between wide and narrow regions.

<FIG> shows a top view (looking down onto the second plane P2) of another example support frame assembly 80c of an effector <NUM> (see <FIG> for orientation). The support frames <NUM>, <NUM>, <NUM> are annotated with Roman Numerals indicating locations having an approximate cross sectional shape as illustrated in <FIG>. Each cross section is taken orthogonal to the respective looped path of each support frame <NUM>, <NUM>, <NUM>. Each support frame <NUM>, <NUM>, <NUM> varies in cross section along its looped path. By varying the cross sections, each support frame <NUM>, <NUM>, <NUM> has variable stiffness/flexibility along its looped path.

<FIG> shows a cross section having a substantially rectangular shape and corresponding to sections of each support frame <NUM>, <NUM>, <NUM> annotated with Roman Numerals I-I. When unconstrained, the parallel segments 81A, 82A, 83A, 81B, 82B, 83B define a respective plane for each support frame <NUM>, <NUM>, <NUM>. The rectangle is long in the plane of the respective support frame. The rectangle is short in the direction orthogonal to the plane of the respective support frame <NUM>, <NUM>, <NUM>. As understood by a person skilled in the pertinent art, this shape permits greater flexibility along an axis aligned with the short edges of the shape compared to the flexibility along an axis aligned with the long edges of the shape. In some examples, the width of the long side of the rectangle is about <NUM> inches (<NUM> millimeters) and the short side of the rectangle is about <NUM> inches (<NUM> millimeters).

<FIG> shows an alternative cross section having an ovoid or oval-shaped shape and corresponding to sections of each support frame <NUM>, <NUM>, <NUM> annotated with Roman Numerals I-I. Like the rectangle illustrated in <FIG>, the oval illustrated in <FIG> is long in the plane of the respective support frame <NUM>, <NUM>, <NUM> and short orthogonal to the respective plane, affecting the relatively flexibility in each direction as understood by a person skilled in the pertinent art. In some examples, the width of the long side of the oval is about <NUM> inches (<NUM> millimeters) and the short side of the oval is about <NUM> inches (<NUM> millimeters).

<FIG> shows a cross section corresponding to sections of each support frame <NUM>, <NUM>, <NUM>, annotated with Roman Numerals II-II. The cross section illustrated in <FIG> has a substantially rectangular shape having a width that is shorter in the plane of the respective support frame <NUM>, <NUM>, <NUM> compared to the width of the rectangular cross section illustrated in <FIG>. The height of the cross section illustrated in <FIG> orthogonal to the plane of the support frame <NUM>, <NUM>, <NUM> can be about equal to the height of the cross section of the rectangle illustrated in <FIG>. Alternatively, the height of the narrower section II-II can be greater than the height of the wider section I-I. Areas of the respective support frame <NUM>, <NUM>, <NUM> having a cross section as illustrated in <FIG> have a higher flexibility in the plane of the respective support frame compared to areas of the respective support frame having a cross section as illustrated in <FIG>. In some examples, the cross section is approximately square shaped having an edge length of about <NUM> inches (<NUM> millimeters).

A support frame <NUM>, <NUM>, <NUM> including rectangular cross sections illustrated in <FIG> can be formed by selecting a sheet having a thickness about equal to the height of the cross sectional shapes illustrated in <FIG> and cutting the sheet to the shape of each respective support frame <NUM>, <NUM>, <NUM> as illustrating in <FIG>, varying the width of each segment of each support frame <NUM>, <NUM>, <NUM> to be wider in regions indicated by the Roman Numerals I-I and narrower in regions indicated by Roman Numerals II-II. Alternatively, the support frame <NUM>, <NUM>, <NUM> can be formed by selecting square or rectangular wire, shaping the wire to form a looped path, and flattening the wire to have regions with wider cross sections I-I and narrower cross sections II-II.

<FIG> shows an alternative cross section corresponding to sections of each support frame <NUM>, <NUM>, <NUM> annotated with Roman Numerals II-II. The cross section has an ovoid or oval-shaped shape that is shorter in the plane of the respective support frame <NUM>, <NUM>, <NUM> compared to the width of the oval cross section illustrated in <FIG>. The height of the cross section illustrated in <FIG> orthogonal to the plane of the support frame <NUM>, <NUM>, <NUM> can be greater than the height of the cross section of the oval illustrated in <FIG>. Areas of the respective support frame <NUM>, <NUM>, <NUM> having a cross section as illustrated in <FIG> have a higher flexibility in the plane of the respective support frame compared to areas of the respective support frame having a cross section as illustrated in <FIG>. In some examples, the cross section is approximately circular having a diameter of about <NUM> inches (<NUM> millimeters).

A support frame <NUM>, <NUM>, <NUM> including ovoid or oval-shaped cross sections illustrated in <FIG> can be formed by selecting a round or oval wire, shaping the wire to form a looped path, and flattening the wire to have regions with wider cross sections I-I and narrower cross sections II-II.

Referring collectively to <FIG>, the end effector <NUM> can include a support frame assembly 80c having some or all of the cross sections illustrated in <FIG> in any combination. Further, each support frame <NUM>, <NUM>, <NUM> can individually include some or all of the cross sections illustrated in <FIG> in any combination. The effector <NUM> can additionally, or alternatively include cross sections not illustrated herein to achieve a difference in flexibility between regions indicated by Roman Numerals I-I and regions indicated by Roman Numerals II-II as understood by a person skilled in the pertinent art according to the teachings herein. Preferably, for the sake of manufacturability, individual support frames <NUM>, <NUM>, <NUM> can include primarily rectangular cross sectional shapes (e.g. <FIG>) or primarily ovoid shapes (e.g. <FIG>) as combining rectangular shapes with ovoid shapes in the same support frame <NUM>, <NUM>, <NUM> can increase cost and/or difficulty in manufacturing.

<FIG> are illustrations of possible transition schemes (knuckles) between regions of a support frame of the end effector. As illustrated in <FIG>, the support frame can transition asymmetrically in width from a wider cross section I-I to a narrower cross section II-II and vice versa. As illustrated in <FIG>, the support frame can transition symmetrically in width from a wider cross section I-I to a narrower cross section II-II and vice versa. The support frame can include only asymmetrical transitions in width, only symmetrical transitions in width, or a mix of asymmetrical and symmetrical transitions in width. Such transitions can be applied to any of the example support members illustrated and otherwise described herein.

<FIG> is an illustration of an asymmetrical support frame <NUM> of the end effector <NUM>. <FIG> are illustrations of cross sections of the asymmetrical support frame <NUM> as indicated in <FIG>. The asymmetrical support frame <NUM> is another example support frame that can be used in place of the outer support frames <NUM>, <NUM> illustrated and described elsewhere herein (e.g. in relation to <FIG>). <FIG> is an illustration of a symmetrical support frame <NUM> of the end effector <NUM>. The symmetrical support frame <NUM> is another example support frame that can be used in place of the central support frame <NUM> illustrated and described elsewhere herein (e.g. in relation to <FIG>). <FIG> are illustrations of cross sections of the symmetrical support frame as indicated in <FIG> is an illustration of a detailed section of the symmetrical support frame as indicated in <FIG>. In some examples, the support frame assembly <NUM> can include two asymmetrical support frames <NUM> and a single symmetrical support frame <NUM>.

<FIG> illustrates that the parallel segments 81A, 81B of the asymmetric support frame <NUM> can have a wider cross section I-I as illustrated in <FIG> compared to the narrower cross section II-II of the connecting segment 81C as illustrated in <FIG>. In some examples, the cross sectional shape of the parallel segments 81A, 81B can be substantially rectangular with a width in the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters) and a height orthogonal to the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters). In some examples, the cross sectional shape of the connecting segment 81C can be substantially rectangular or square with a width in the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters) and a height orthogonal to the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters). Further, the proximal segments 81E, 81D can have a cross section I-I of approximately the same dimensions as the parallel segments 81A, 81B.

<FIG> illustrates that a majority of the length of the parallel segments 82A, 82B of the symmetric support frame <NUM> can have a wider cross section I-I as illustrated in <FIG> compared to the narrower cross section II-II of the connecting segment 82C. The parallel segments 82A, 82B can include a tapering transition as illustrated in <FIG> and indicated in <FIG> that tapers from the wider width of the wider cross section I-I to the narrower width II-II of the narrower cross section II-II. A distal portion of each parallel segment 82A, 82B distal to the tapering transition can have the narrower cross section I-I. The proximal segments 82E, 83D can have a cross section I-I of approximately the same dimensions as the majority of the length of the parallel segments 82A, 82B. The symmetric support frame <NUM> can further include a narrower width sections 82F, <NUM> that respectively include a proximal portion of a respective parallel segment 82A, 82B and a distal portion of a respective proximal segment 82D, 82E. These narrower width sections 82F, <NUM> can have a cross section II-II as illustrated in <FIG>. These narrower width sections 82F, <NUM> can have a length of approximately <NUM> inches (<NUM> millimeters). The symmetric support frame <NUM> can have a width of approximately <NUM> inches (<NUM> millimeters) as measured between outer edges of the parallel segments 82A, 82B in the plane of the support frame <NUM> as illustrated.

As illustrated in <FIG>, in some examples, the narrower cross sectional regions II-II can have a cross sectional shape that is substantially rectangular or square with a width in the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters) and a height orthogonal to the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters).

As illustrated in <FIG>, in some examples, the wider cross sectional regions I-I can have a substantially rectangular cross sectional shape with a width in the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters) and a height orthogonal to the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters).

<FIG> is an illustration of an asymmetrical support frame <NUM> of the end effector <NUM>. <FIG> are illustrations of cross sections of the asymmetrical support frame <NUM> as indicated in <FIG>. The asymmetrical support frame <NUM> is another example support frame that can be used in place of the outer support frames <NUM>, <NUM> illustrated and described elsewhere herein (e.g. in relation to <FIG>). <FIG> are illustrations of detailed sections of the asymmetrical support frame <NUM> as indicated in <FIG>. <FIG> is an illustration of a symmetrical support frame <NUM> of the end effector <NUM>. The symmetrical support frame <NUM> is another example support frame that can be used in place of the central support frame <NUM> illustrated and described elsewhere herein (e.g. in relation to <FIG>). <FIG> are illustrations of cross sections of the symmetrical support frame as indicated in <FIG> are illustrations of a detailed section of the symmetrical support frame as indicated in <FIG>. In some examples, the support frame assembly <NUM> can include two asymmetrical support frames <NUM> and a single symmetrical support frame <NUM>.

<FIG> illustrates that the parallel segments 81A, 81B of the asymmetric support frame <NUM> can have a wider cross section I-I as illustrated in <FIG> compared to the narrower cross section II-II of the connecting segment 81C. In some examples, the cross sectional shape of the parallel segments 81A, 81B can be substantially rectangular with a width in the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters) and a height orthogonal to the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters). In some examples, the cross sectional shape of the connecting segment 81C, at least in the area indicated by section A-A in <FIG>, can be substantially square with a width in the plane of the support frame <NUM> less than the width of the cross section of the parallel segments 81B, 81A. The cross section I-I can have a width of about <NUM> to about <NUM> inches (about <NUM> to <NUM> millimeters). The cross section I-I can have a height of about <NUM> inches (about <NUM> millimeters). Further, the proximal segments 81E, 81D can have a cross section I-I of approximately the same dimensions as the parallel segments 81A, 81B. A length L1 of the frame 81B as measured from a distal end to the proximal end (indicated as "y" in <FIG>) can be approximately <NUM> inches (or <NUM>) and a width W1 as measured from frame 81A to frame 81B is approximately <NUM> inches (or <NUM>).

<FIG> illustrates transition, on the connector segment 81C between the wider cross section I-I illustrated in <FIG> and the narrower cross section II-II illustrated in <FIG>.

<FIG> illustrates a serrated segments of the support frame <NUM> shaped to secure the two ends of the loop member to the distal portion of the shaft <NUM> or connector tubing <NUM>.

<FIG> illustrates that a majority of the length of the parallel segments 82A, 82B of the symmetric support frame <NUM> can have a wider cross section I-I as illustrated in <FIG> compared to the narrower cross section II-II of the connecting segment 82C as illustrated in <FIG>. The parallel segments 82A, 82B can include a tapering transition as illustrated in <FIG> and indicated in <FIG> that tapers from the wider width of the wider cross section I-I to the narrower width II-II of the narrower cross section II-II. <FIG> illustrates a serrated segments of the support frame <NUM> shaped to secure the two ends of the loop member to the distal portion of the shaft. We have devised a configuration of the support frame in <FIG> (as well as <FIG>) such that an aspect ratio of the length L1 to width W1 (i.e., L1/W1) may be from <NUM> to <NUM>. In the preferred embodiments, the aspect ratio (L1/W1) of the frame support of <FIG> and <FIG> is one of <NUM> or <NUM>.

As illustrated in <FIG>, in some examples, the narrower cross sectional regions II-II can have a cross sectional shape that is substantially rectangular with a width in the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters) and a height orthogonal to the plane of the support frame <NUM> of about <NUM> inches (<NUM> millimeters).

<FIG> is an illustration of crimped or serrated features <NUM> at ends of the support frames. The crimped or serrated features <NUM> can facilitate engagement of the support frames <NUM>, <NUM>, <NUM> to the distal end 14A of the shaft <NUM> (e.g. within the connector tubing <NUM>). In particular, the serrations <NUM> of each support frame can be molded together with the connector tubing <NUM> or affixed (e.g., adhesive or epoxy) with the connector tubing <NUM>. To ensure that each loop frame is structurally rigid where the loop comes out of the tubing <NUM>, each serration <NUM> of each support frame are affixed directly to the tubing <NUM> and one serration <NUM> does not engage or mate with another serration <NUM> from another support member. This ensures that forces transmitted to frame <NUM> from the loop distal end are not transmitted to itself via the serrations or to other frames <NUM> and <NUM> due to the serrations <NUM> being independently affixed to the tubing <NUM> instead of other serrations <NUM>.

<FIG> are illustrations of deformation of support frame assemblies as a result of application of various forces. Each support frame assembly <NUM> includes a first support frame <NUM>, a second support frame <NUM>, and a third support frame <NUM>. The first and third support frames <NUM>, <NUM> are outer support frames surrounding the second central support frame <NUM>. The support frame assembly <NUM> includes a mechanical linkage <NUM> joining the first, second, and third support frames <NUM>, <NUM>, <NUM> at the distal vertex.

<FIG> illustrates the first support frame <NUM> pressed into a planar surface S as an apex of a wedge W is pressed with a force F1 into the third support frame <NUM>. The support frame assembly <NUM> is aligned approximately orthogonal to the planar surface S. The force F1 is applied approximately orthogonal to, and in a direction toward the planar surface S. The force F1 is applied centrally along the length of the outer parallel segment 83B of the third support frame <NUM>. The outer parallel segment 83B of the third support frame bows toward the surface S as a result of the force F1. The support frame assembly <NUM> can be configured to resist spine-to-spine contact when the force F1 is applied. In <FIG>, the outer parallel segment 83B of the third support frame is bowed to contact the second support frame <NUM>. The force F1 sufficient to move the outer parallel segment 83B of the third support frame <NUM> into contact with the second support frame <NUM> can be a metric used to compare variations in support frame assembly design (e.g. with differing support frame cross section design) where a higher force F1 indicates a more favorable result for this test.

<FIG> illustrates the support frame assembly <NUM> compressed between two planar surfaces S1, S2 with a force F2. The planar surfaces S1, S2 are aligned approximately parallel to each other. The support frame assembly <NUM> is aligned approximately orthogonal to the planar surfaces S1, S2. An outer parallel segment 81A of the first support frame <NUM> is pressed by the first planar surface S1. The outer parallel segment 83B of the third support frame <NUM> is pressed by the second planar surface S2. As a result of the compression by the force F2 between the planar surfaces S1, S2, the outer parallel segments 81A, 83B bow toward the opposite planar surface S1, S2. The support frame assembly <NUM> can be configured to resist spine-to-spine contact when the force F2 is applied. The force F2 sufficient to move the outer parallel segment 83B of the third support frame <NUM> or the outer parallel segment 81A of the first support frame <NUM> into contact with the second support frame <NUM> can be a metric used to compare variations in support frame assembly design (e.g. with differing support frame cross section design) where a higher force F2 indicates a more favorable result for this test. In the preferred embodiments, F1 or F2 is approximately <NUM> gram-force or greater. The range of suitable force is about <NUM> gram-force to <NUM> gram-force for F1 and <NUM> gram-force to <NUM> gram-force.

<FIG> illustrates the support frame assembly <NUM> compressed by a planar surface S applying a force F3 to a distal end of the support frame assembly <NUM>. The distal portion 14A of the shaft <NUM> is held at a position in the proximal direction of the connector tubing <NUM> such that the longitudinal axis L-L defined by the shaft <NUM> is approximately orthogonal to the surface S. The force F3 is applied to the connector segments 81C, 83C of the first and third support frames <NUM>, <NUM>. As a result of the compression by the force F3 in the direction of the longitudinal axis L-L, the support frame assembly <NUM> and connector tubing <NUM> deflect out of alignment with the longitudinal axis L-L. This is to ensure the distal section 14A of shaft <NUM> and/or end effector are sufficiently flexible so that the end effector and/or distal section of the shaft buckles at a sufficiently low force when applied to a heart wall to inhibit the end effector from puncturing the heart wall.

<FIG> illustrates the support frame assembly <NUM> deflected by a force F4 applied approximately orthogonal to the support frame assembly near the mechanical linkage <NUM> at the distal vertex. The distal portion 14A of the shaft <NUM> is held near the connector tubing <NUM>. As a result of the force F4, the support frame <NUM> is deflected out of alignment with the longitudinal axis L-L. In some use cases, it can be desired to have a greater or lesser deflection as a result of Force F4 depending on the geometry of a treatment area and/or preferences of a physician regarding tactile feedback.

<FIG> are illustrations of an example rectangular or ovular mechanical linkage 50a having a closable single opening and used for joining the loop members according to aspects of the present invention. Alternative mechanical linkages 50b-h are illustrated in <FIG>. The linkages 50a-h can be used to join loop members (or other electrode carrying structures) of catheter-based devices similar to how the loop members <NUM>, <NUM>, <NUM> are joined at the distal vertex as described and illustrated herein. The mechanical linkage can serve to inhibit electrodes <NUM> on the spines 1A, 2A, 3A, 1B, 2B, 3B of the end effector <NUM> from coming into contact with each other. Loop members <NUM>, <NUM>, <NUM> are spatially affixed relative to each other by the connector tubing <NUM> near the proximal end of the end effector <NUM>. Without the mechanical linkage, the distal ends of the respective loop members <NUM>, <NUM>, <NUM> are free to move in relation to each other when acted on by a force such as the forces F1, F2, F3, F4 illustrated in <FIG>. The mechanical linkage is sized, shaped, and otherwise configured to allow the end effector <NUM> to be collapsed for delivery through a catheter or guiding sheath to a treatment site. Ease of assembly of the end effector <NUM> is also a design consideration for the mechanical linkage.

<FIG> illustrates the mechanical linkage 50a joining three loop members <NUM>, <NUM>, <NUM>. The mechanical linkage 50a includes a seam or gap <NUM>. <FIG> illustrate the mechanical linkage 50a as manufactured. The linkage 50a is initially formed as an open clip. A stiff material, preferably metal, is formed or cut into a shape resembling an open paper clip. The individual loop members <NUM>, <NUM>, <NUM> can be constructed prior to being joined by the mechanical linkage 50a. In some example methods of construction, the end effector <NUM> can be entirely contracted and affixed to the shaft <NUM> before the linkage 50a is affixed to the loop members <NUM>, <NUM>, <NUM>. The linkage 50a can include an opening <NUM> sized to allow loop members <NUM>, <NUM>, <NUM>, one at a time, to be inserted into the linkage 50a. The opening <NUM> as manufactured can be larger than respective diameters of the loop members <NUM>, <NUM>, <NUM> near the distal vertex. Once the loop members <NUM>, <NUM>, <NUM> are inserted into the linkage 50a, the opening <NUM> can be collapsed as illustrated in <FIG>. The opening <NUM> can be collapsed by crimping a free open end of the linkage 50a until it lines up with the other open end of the linkage 50a. When the opening is collapsed, a short side of the linkage 50a can be moved through an angle of about <NUM>° and the free open end on a long side of the linkage 50a can be moved through an angle of about <NUM>° as illustrated in <FIG>.

The mechanical linkage 50a illustrated in <FIG> is symmetrical. Alternatively, the mechanical linkage 50a can be asymmetrical to promote consistent collapsing geometry of the end effector for delivery through a catheter.

<FIG> are illustrations of an example rectangular or ovular mechanical linkage 50b having a single opening and used for joining the loop members <NUM>, <NUM>, <NUM>. The example mechanical linkage 50b has four contiguous sides. Compared to the example mechanical linkage 50a illustrated in <FIG>, the example mechanical linkage 50b in <FIG> lacks a gap or seam <NUM>. During assembly, loop members <NUM>, <NUM>, <NUM> can be fed through the opening <NUM> of the linkage 50b before the ends of the loop members <NUM>, <NUM>, <NUM> are affixed to the shaft <NUM>.

The mechanical linkage 50b illustrated in <FIG> is symmetrical. Alternatively, one side of the ring can be wider than the other to promote the loop members <NUM>, <NUM>, <NUM> to fold to a particular side when the end effector <NUM> is collapsed for delivery through a catheter or guiding sheath.

<FIG> are illustrations of an example rectangular or ovular mechanical linkage 50c having three openings <NUM>, <NUM>, <NUM> and used for joining the loop members <NUM>, <NUM>, <NUM>. Each opening <NUM>, <NUM>, <NUM> can be shaped and otherwise configured to receive a loop member <NUM>, <NUM>, <NUM>.

The linkage 50c can include a circular opening <NUM> to receive the central, symmetric loop member <NUM>. The central loop member <NUM> can be approximately orthogonal to the linkage 50c at the distal vertex, allowing for the respective opening <NUM> of the linkage 50c to be circular. The linkage 50c can include two oblong openings <NUM>, <NUM> each respectively shaped to receive a respective outer, asymmetrical loop member <NUM>, <NUM>. The outer loop members <NUM>, <NUM> can pass through the linkage 50c at a non-orthogonal angle. The oblong shape of the corresponding linkage openings <NUM>, <NUM> can be elongated to account for non-orthogonal trajectory of the outer loop members <NUM>, <NUM> through the linkage 50c.

Each of the loop members <NUM>, <NUM>, <NUM> can include a respective tubular housing <NUM>, <NUM>, <NUM> covering a majority of the support frame <NUM>, <NUM>, <NUM> for that loop member <NUM>, <NUM>, <NUM>. To reduce the separation of the support frames <NUM>, <NUM>, <NUM> at the distal vertex, the loop members <NUM>, <NUM>, <NUM> need not include tubular housing <NUM>, <NUM>, <NUM> near the distal vertex. The openings <NUM>, <NUM>, <NUM> of the linkage 50c can be sized to allow the support frame <NUM>, <NUM>, <NUM> of the loop members to pass through, but need not be sized to allow the tubular housings <NUM>, <NUM>, <NUM> to pass through. During assembly, the support frames <NUM>, <NUM>, <NUM> can be positioned through the openings <NUM>, <NUM>, <NUM> of the linkage 50c before the tubular housings <NUM>, <NUM>, <NUM> are added to the loop members <NUM>, <NUM>, <NUM>.

Alternatively, the openings <NUM>, <NUM>, <NUM> can be sized to allow the tubular housings <NUM>, <NUM>, <NUM> of the loop members <NUM>, <NUM>, <NUM> to pass therethrough to allow for a design where some or all of the tubular housings <NUM>, <NUM>, <NUM> cross the distal vertex and/or to allow for an assembly process where the tubular housings <NUM>, <NUM>, <NUM> are affixed to the loop members <NUM>, <NUM>, <NUM> before the mechanical linkage 50c.

<FIG> are illustrations of an example cylindrical mechanical linkage 50d having three passageways <NUM>, <NUM>, <NUM> and used for joining support members <NUM>, <NUM>, <NUM> of the loop members <NUM>, <NUM>, <NUM>. The openings <NUM>, <NUM>, <NUM> of the linkage 50d can be sized to allow the support frame <NUM>, <NUM>, <NUM> of the loop members to pass through, but need not be sized to allow the tubular housings <NUM>, <NUM>, <NUM> to pass through. During assembly, the support frames <NUM>, <NUM>, <NUM> can be positioned through the openings <NUM>, <NUM>, <NUM> of the linkage 50d before the tubular housings <NUM>, <NUM>, <NUM> are added to the loop members <NUM>, <NUM>, <NUM>.

<FIG> are illustrations of an example cylindrical mechanical linkage 50e having three passageways <NUM>, <NUM>, <NUM> and used for joining the loop members <NUM>, <NUM>, <NUM> with tubular housings <NUM>, <NUM>, <NUM> over the support members <NUM>, <NUM>, <NUM>. In some examples, the passageways <NUM>, <NUM>, <NUM> can be sized to allow for an assembly process where the tubular housings <NUM>, <NUM>, <NUM> are affixed to the loop members <NUM>, <NUM>, <NUM> before the mechanical linkage 50e.

<FIG> are illustrations of additional example mechanical linkages. <FIG> illustrates a mechanical linkage 50f including polymer shaped to closely conform to the dimensions of the loop members <NUM>, <NUM>, <NUM>. The linkage 50f can include an adhesive. The linkage 50f can be applied by hand, over molded, or by other means as understood by a person skilled in the pertinent art. <FIG> illustrates a mechanical linkage <NUM> including an adhesive. <FIG> illustrates a tapered ring linkage <NUM> having an annular opening <NUM> through which the three loop members <NUM>, <NUM>, <NUM> can extend and a height that tapers from a larger dimension H2 to a smaller dimension H1 across the diameter of the opening <NUM>. The link <NUM> has a portion on one side that is narrower on one side (H1) as compared to the portion H2 on the other side. The narrowed portion H1 encourages the loops <NUM>, <NUM> and <NUM> to bend toward the narrowed side when retracting into the sheath. This can be used to reduce forces required for sheath retraction.

<FIG> are illustrations of an example loop member <NUM> having an inner housing <NUM> and outer housing <NUM> surrounding the support frame <NUM>. The illustrated loop member <NUM> can be used in place of loop members <NUM>, <NUM>, <NUM> illustrated and otherwise disclosed herein according to the teachings herein. In particular, it can be advantageous to use the illustrated loop member in place of loop members <NUM>, <NUM>, <NUM> illustrated in <FIG> and <FIG>. The inner housing <NUM> and outer housing <NUM> can collectively function as the tubular housing <NUM>, <NUM>, <NUM> illustrated elsewhere herein.

The outer housing <NUM> can include polymeric tube (e.g. thermoplastic polyurethane) having a single lumen sized to house the support frame <NUM> and wires <NUM> that provide electrical connections to the end effector electrodes <NUM>. The lumen of the outer housing <NUM> can also be sized to house an irrigation tube <NUM> having an irrigation lumen therethrough. In this configuration, the support frame is surrounded by a sleeve to isolate its edges from damaging the conductors. The support frame, sleeve and conductors are in one lumen, shown in <FIG> (whereby irrigation is optional). A small diameter tube <NUM> in <FIG> is a separate piece that is bonded to the larger tube, with the purpose of reducing the outer diameter when passing through the mechanical linkage.

The inner housing <NUM> (<FIG>) can be shaped, sized, and otherwise configured to closely surround the support frame <NUM>. The inner housing <NUM> can include a polymeric material, for example a shrink sleeve applied during a reflow process. Because neither the wires <NUM> nor the irrigation tube <NUM> need extend beyond the spines of the loop member, the outer housing <NUM> need not cover the connector segment of the loop member. The inner housing <NUM> can be dimensioned to allow less separation between the loop members <NUM>, <NUM>, <NUM> near the distal vertex compared to a loop member having a tubular housing dimensioned similar to the outer housing <NUM> crossing, or extending near, the distal vertex. Further, the distal end of the end effector <NUM> can collapse to a smaller dimension compared to an end effector having a tubular housing dimensioned similar to the outer housing <NUM> crossing, or extending near, the distal vertex.

Within the outer housing <NUM>, the inner housing <NUM> can be bonded to the outer housing <NUM>. The bond between the inner housing <NUM> and outer housing <NUM> can inhibit fluid leakage. The bond between the inner housing <NUM> and outer housing <NUM> can promote conformity of the shape of the outer housing <NUM> to that of the support frame <NUM> inhibiting shifting of the support frame <NUM> within the outer housing <NUM> when the end effector <NUM> is deformed from its unconstrained configuration.

At the distal ends of the outer housing <NUM>, the loop member <NUM> can include a joint <NUM> configured to inhibit fluid ingress into the outer housing <NUM>. The joint <NUM> can be bonded to the outer housing <NUM> and inner housing <NUM>.

<FIG> are illustrations of an alternative example loop member having a tubular housing 90a, 90b having two lumens 90a or three lumens 90b therethrough in which the support frame <NUM>, conductive wires <NUM>, and an irrigation tube <NUM> are positioned. Regardless of whether the tubular housing 90a, 90b has two or three lumens, the loop member can have an outer appearance similar to as illustrated in <FIG> illustrates a cross section of the loop member having a tubular housing 90a with two lumens. The design purpose of the embodiment in <FIG> is to isolate the support member from damaging the conductors or irrigation lines. <FIG> illustrates a cross section of the loop member having a tubular housing 90b with three lumens. The cross sections illustrated in <FIG> are viewed along a spine of the loop member as indicated in <FIG>.

<FIG> illustrates the support frame <NUM> positioned in one lumen of the dual lumen tubular housing 90a and the wires <NUM> and irrigation tube <NUM> positioned in the other lumen of the dual lumen tubular housing 90b. Separation of the support frame <NUM> from the wires <NUM> and irrigation tube <NUM> can inhibit edges of the support frame <NUM> from abating insulation the wires <NUM> or walls of the irrigation tube <NUM>. The dual lumen tubular housing 90b can be used in place of tubular housings <NUM>, <NUM>, <NUM> illustrated elsewhere herein.

<FIG> illustrates the support frame <NUM> positioned in a first lumen of the tri lumen tubular housing 90b, wires <NUM> in a second lumen of the tri lumen tubular housing 90b, and an irrigation tube <NUM> in a third lumen of the tri lumen tubular housing 90b. The tri lumen tubular housing 90c can be used in place of tubular housings <NUM>, <NUM>, <NUM> illustrated elsewhere herein. The purpose of this design in <FIG> is to isolate the irrigation line <NUM> from contact with the other materials. As an alternative to the illustration of <FIG>, the loop member <NUM> need not include an irrigation tube <NUM>, and the lumen of the tubular housing 90b in which the irrigation tube <NUM> is illustrated can be used direction for irrigation.

Spine covers <NUM>, 90a, 90b can be preferably <NUM> French to <NUM> French. In some examples, the spine cover <NUM> illustrated in <FIG>, compared to the spine covers 90a, 90b illustrated in <FIG>, can have more usable interior space for the same French sizing, allowing for a larger support frame, larger irrigation tube <NUM>, and/or increased volume of wires <NUM>.

<FIG> are illustration of example end effector electrodes <NUM> with varying degrees of surface roughness. Contact resistance between an electrode and tissue is inversely proportionate to the surface area of the electrode in contact with the tissue. In other words, electrical energy is transferred more efficiently from the electrode to the tissue and vice versa when contact area between the electrode and tissue is increased. For diagnostic measurements, more efficient electrical energy transfer from tissue to electrode results in clearer, less noisy, more accurate electrical signals (sensor measurements). Dimensions of the footprint, or perimeter, of the electrode is limited by the geometry of the vasculature through which the end effector <NUM> travels to reach a treatment site, the geometry of the treatment site, and the geometry of other components of the end effector <NUM>. Micro-roughness on the electrode surface increases effective surface area of the electrode, thereby reducing contact resistance when the electrode surface is pressed to tissue, without increasing the footprint of the electrode. However, increasing surface roughness can also promote thrombus formation on the electrode which can lead to complications during treatment.

<FIG> illustrates a control electrode <NUM> with an untreated surface. <FIG> illustrates an electrode <NUM> compacted from a swaging process. The compacted electrode is compressed to have an outer circumference that approximates the outer circumference of the tubular housing <NUM>, <NUM>, <NUM>. <FIG> illustrates a micro-blasted electrode <NUM> that is not swaged. Micro-blasting introduces surface roughness on a micrometer scale. The surface can alternatively be roughed by other suitable process such as chemical etching, sputtering, and/or other deposition method. <FIG> illustrates a micro-blasted and swaged electrode <NUM>.

The combination of roughening (e.g. micro-blasting) and swaging the electrode surface creates a controlled, shallow surface roughness. Swaging reduces the ring diameter of the electrode <NUM> and can also flatten some vertical features created from roughening, resulting in an electrode with a higher surface area and relatively flattened outer surface. The higher surface area can be effective to reduce contact resistance between an electrode and tissue.

Surface roughness can be characterized by roughness parameter Ra representing an arithmetical mean deviation of a profile of the surface. As illustrated in <FIG>, in some examples, some or all of the electrodes <NUM> of the end effector <NUM> can have a surface roughness parameter Ra measuring from about <NUM> micrometers to about <NUM> micrometers. This surface roughness can be effective to increase surface area of the electrodes <NUM> to decrease contact resistance to tissue while not significantly promoting thrombus formation. In comparison, as illustrated in <FIG>, the untreated surface can have a surface roughness parameter Ra measuring from about <NUM> micrometers to about <NUM> micrometers.

Claim 1:
An apparatus (<NUM>) for a mapping catheter comprising:
a tubular member (<NUM>) extending along a longitudinal axis (L-L);
a first loop member (<NUM>) comprising two spine members (1A, 1B) extending from the tubular member and connected to an arcuate member (1C), the first loop member arrayed on a first plane (P1);
a second loop member (<NUM>) comprising two spine members (2A, 2B) extending from the tubular member and connected to an arcuate member (2C), the second loop member arrayed on a second plane (P2) that intersects with the first plane;
a third loop member (<NUM>) comprising two spine members (3A, 3B) extending from the tubular member and connected to an arcuate member (3C), the third loop member arrayed on a third plane (P3) that intersects with the first plane and the second plane so that majority of the length each of the three loop members is non-coplanar with the majority of the length of at least one of the other three loop members in an unconstrained configuration,
each of the three loop members respectively comprising a support frame (<NUM>, <NUM>, <NUM>) extending through a respective loop member of the three loop members and affixed to a distal portion of the tubular member,
each of the respective support frames defining a respective looped path of the respective loop member, and
each of the respective support frames comprising a respective cross sectional shape orthogonal to the respective looped path, each of the respective cross sectional shapes varying along the respective looped path; and
each of the first, second and third loop members including a plurality of electrodes (<NUM>) disposed thereon each loop member.