Patent Description:
Electrophysiology catheters are commonly-used for mapping electrical activity in the heart. Various electrode designs are known for different purposes. In particular, catheters having basket-shaped electrode arrays are known and described, for example, in <CIT>, <CIT><CIT>.

Basket catheters typically have an elongated catheter body and a basket-shaped electrode assembly mounted at the distal end of the catheter body. The basket assembly has proximal and distal ends and comprises a plurality of spines connected at their proximal and distal ends. Each spine comprises at least one electrode. The basket assembly has an expanded arrangement wherein the spines bow radially outwardly and a collapsed arrangement wherein the spines are arranged generally along the longitudinal axis of the catheter body.

It has been observed that there is an increased risk of thrombus formation when using catheters that change shape from a linear delivery configuration to an expanded diagnostic configuration. Thrombus formation may occur around device features that slow down the flow of blood. Catheters typically release irrigation fluid to reduce this risk. However, diagnostic catheters include only a single irrigation lumen that has a port at the distal end of the catheter. Oftentimes, this single port is not sufficient to flush the entire device from the proximal end to the distal end which may lead to thrombus formation. Therefore, it is desirable to design a catheter that has an improved irrigation system to reduce or eliminate the risk of thrombus formation. The techniques of this disclosure satisfy this and other needs as described in the following materials.

<CIT> discloses a shaft from which an expandable membrane extends. The expandable membrane incorporates an electrode assembly including longitudinally oriented distal branches. The electrode assembly is populated such that an electrode is associated with the irrigation holes. Further known electrode arrays are disclosed in <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

The present disclosure is directed to a catheter, the catheter includes an elongated catheter body having proximal and distal ends and at least one irrigation lumen therethrough and an irrigated electrode assembly at the distal end of the catheter body, the irrigated electrode assembly comprising a plurality of spines having proximal and distal ends, the plurality of spines being connected at their proximal ends, each spine having a plurality of electrodes, and at least one irrigation port adjacent a distal end of the elongated catheter body in fluid communication with the at least one irrigation lumen.

In one aspect, each spine may have a plurality of irrigation ports in fluid communication with the spine lumen.

In one aspect, at least one of the irrigation ports is a dedicated irrigation port. In addition, at least one of the irrigation ports is integrated with an electrode having a plurality of perforations. Accordingly, a combination of dedicated irrigation ports and integrated irrigation ports is employed.

In one aspect, the irrigation ports are distributed evenly across the irrigated electrode assembly.

In one aspect, the plurality of spines are connected at their distal ends to form an irrigated basket-shaped electrode assembly having an expanded arrangement wherein the spines bow radially outwardly and a collapsed arrangement wherein the plurality spines are arranged generally along a longitudinal axis of the catheter body.

In one aspect, the at least one irrigation lumen comprises a second irrigation lumen having a second irrigation port adjacent the distal ends of the plurality of spines and in fluid communication with the at least one irrigation lumen.

In one aspect, the catheter further comprises an expander having proximal and distal ends and a central lumen in fluid communication with the at least one irrigation port adjacent the proximal end of the plurality of spines and the second irrigation port adjacent the distal ends of the plurality of spines, the expander slidably disposed within the at least one irrigation lumen and aligned with the longitudinal axis of the catheter body, wherein the plurality of spines are attached at their distal ends to the expander and each spine includes a spine lumen and a least one spine irrigation port in fluid communication with the spine lumen, each spine lumen being in fluid communication with the at least one irrigation lumen.

In one aspect, the catheter comprises an elongated catheter body having proximal and distal ends and at least one irrigation lumen therethrough and an irrigated electrode assembly at the distal end of the catheter body, the irrigated electrode assembly comprising a plurality of spines connected at their proximal ends, each spine comprising a plurality of electrodes, a spine lumen and at least one irrigation port in fluid communication with the spine lumen, wherein each spine lumen is in fluid communication with the irrigation lumen.

This disclosure also includes a method for treatment, which is not part of the invention, that may involve providing a catheter comprising an elongated catheter body having proximal and distal ends and at least one irrigation lumen therethrough and an irrigated electrode assembly at the distal end of the catheter body, the irrigated electrode assembly comprising a plurality of spines having proximal and distal ends, the plurality of spines being connected at their proximal ends, each spine having a plurality of electrodes, and at least one irrigation port adjacent a proximal end of the irrigated electrode assembly in fluid communication with the at least one irrigation lumen, advancing the distal end of the catheter with the irrigated electrode assembly to a desired region within a patient, positioning the irrigated electrode assembly such that at least one electrode is in contact with tissue, and supplying irrigation fluid to the irrigation lumen so that the irrigation fluid perfuses through the at least one irrigation port.

In one aspect, the method for treatment may involve providing a catheter comprising an elongated catheter body having proximal and distal ends and at least one irrigation lumen therethrough and an irrigated electrode assembly at the distal end of the catheter body, the irrigated electrode assembly comprising a plurality of spines connected at their proximal ends, each spine comprising a plurality of electrodes, a spine lumen and at least one irrigation port in fluid communication with the spine lumen, wherein each spine lumen is in fluid communication with the irrigation lumen, advancing the distal end of the catheter with the irrigated electrode assembly to a desired region within a patient, positioning the irrigated electrode assembly such that at least one electrode is in contact with tissue and supplying irrigation fluid to the irrigation lumen so that the irrigation fluid perfuses through the irrigation ports.

In one aspect, electrical signals may be received from the at least one electrode in contact with tissue.

In one aspect, radio frequency energy may be delivered to the at least one electrode in contact with tissue to form a lesion.

In one aspect, the desired region may be an atrium or a ventricle of the heart.

Further features and advantages will become apparent from the following and more particular description of the preferred embodiments of the disclosure, as illustrated in the accompanying drawings, and in which like referenced characters generally refer to the same parts or elements throughout the views, and in which:.

At the outset, it is to be understood that this disclosure is not limited to particularly exemplified materials, architectures, routines, methods or structures as such may vary. Thus, although a number of such options, similar or equivalent to those described herein, can be used in the practice or embodiments of this disclosure, the preferred materials and methods are described herein.

It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of this disclosure only and is not intended to be limiting.

The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of the present disclosure and is not intended to represent the only exemplary embodiments in which the present disclosure can be practiced. The term "exemplary" used throughout this description means "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary embodiments of the specification. It will be apparent to those skilled in the art that the exemplary embodiments of the specification may be practiced without these specific details. In some instances, well known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary embodiments presented herein.

For purposes of convenience and clarity only, directional terms, such as top, bottom, left, right, up, down, over, above, below, beneath, rear, back, and front, may be used with respect to the accompanying drawings. These and similar directional terms should not be construed to limit the scope of the disclosure in any manner.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the disclosure pertains.

Finally, as used in this specification and the appended claims, the singular forms "a, "an" and "the" include plural referents unless the content clearly dictates otherwise.

Certain types of electrical activity within a heart chamber are not cyclical. Examples include arterial flutter or arterial fibrillation, and ventricular tachycardia originating in scars in the wall of the ventricle that have resulted from infarcts. Such electrical activity is random from beat to beat. To analyze or 'map' this type of electrical activity, it is desirable to obtain the 'picture' as quickly as possible, such as within one heartbeat. Typically, a basket-shaped electrode assembly having a high electrode density may be used to accurately map this electrical activity.

As discussed above, there is an increased risk of thrombus formation when using a catheter that has features that slow down blood flow. Features that slow down blood flow include, for example, surface structures that transition from a flat surface to a concave surface, puller wires, and those features that narrow the blood flow channel. Blood flow may also be reduced where a small gap is formed between two parts of a diagnostic device. It is these types of catheters that will benefit from an improved irrigation system. Consequently, the catheters discussed below include a plurality of irrigation ports to strategically supply irrigation fluid around such structures in order to eliminate thrombus formation.

Referring now to <FIG>, catheter <NUM> comprises an elongated catheter body <NUM> having proximal and distal ends and a control handle <NUM> at the proximal end of the catheter body, with a basket-shaped electrode assembly <NUM> having a plurality of spines <NUM>, each carrying multiple electrodes <NUM>, mounted at the distal end of the catheter body <NUM>. The catheter body <NUM> comprises an elongated tubular construction having a single, axial or central lumen (not shown), but can optionally have multiple lumens if desired. To enable accurate mapping of electrical signals, for example to detect most or substantially all of the electrical function of the right or left atrium in as little as a single heartbeat, it may be desirable to provide an array of electrodes with a relatively high density. As such, the numbers of spines <NUM> employed may be six, eight, ten, twelve or any other suitable number. Spines <NUM> may be evenly or unevenly distributed radially. Further, each spine <NUM> may include multiple electrodes <NUM>, such as at least eight, ten, twelve, fourteen and sixteen electrodes per spine. Similarly, the electrodes may be evenly distributed along the spine or may be skewed proximally, centrally or distally to facilitate analysis of the measured electrical signals.

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. One construction comprises an outer wall made of polyurethane or PEBAX® (polyether block amide). The outer wall comprises 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 distal end of the catheter body will rotate in a corresponding manner. The outer diameter of the catheter body <NUM> is not critical, but generally should be as small as possible and may be no more than about <NUM> french depending on the desired application. In one aspect, the overall diameter of the catheter body <NUM> may relate to the number of electrodes <NUM> implemented by basket-shaped electrode assembly <NUM> in order to accommodate the associated electrical leads. For example, a twelve-spine design with each spine carrying sixteen electrodes for a total of <NUM> electrodes, a ten-spine design with each spine carrying sixteen electrodes for a total of <NUM> electrodes and an eight-spine design with each spine carrying sixteen electrodes for a total of <NUM> electrodes may utilize up to a <NUM> french catheter body. Likewise the thickness of the outer wall is not critical, but may be thin enough so that the central lumen can accommodate a puller wire, lead wires, sensor cables and any other wires, cables or tubes. If desired, the inner surface of the outer wall is lined with a stiffening tube (not shown) to provide improved torsional stability. An example of a catheter body construction suitable for use in connection with the present invention is described and depicted in <CIT>.

The basket-shaped electrode assembly <NUM> may also include an expander <NUM> that is generally coaxial with the catheter body <NUM> and extends from the proximal end of catheter body <NUM> through the central lumen and is attached, directly or indirectly, to the distal ends of spines <NUM>. The expander <NUM> is afforded longitudinal movement relative to the catheter body so that it can move the distal ends of the spines <NUM> proximally or distally relative to the catheter body <NUM> to radially expand and contract, respectively, the electrode assembly. Since the proximal ends of spines <NUM> are secured to the catheter body <NUM>, relative movement of expander <NUM> in the proximal direction shortens the distance between the distal and proximal ends of spines <NUM>, causing them to bow outwards into an expanded arrangement. The expander <NUM> comprises a material sufficiently rigid to achieve this function. Alternatively or in addition, spines <NUM> may include a material as described below that facilitates assuming the expanded arrangement, such as a shape memory material, so that expander <NUM> may be omitted or may be used to aid the transition between the expanded and collapsed arrangements. In an embodiment, the expander <NUM> may comprise a wire or hypotube formed from a suitable shape memory material, such as a nickel titanium alloy as described below. As will be appreciated, different relative amounts of movement of the expander <NUM> along the longitudinal axis may affect the degree of bowing, such as to enable the spines <NUM> to exert greater pressure on the atrial tissue for better contact between the tissue and the electrodes on the spines. Thus, a user can change the shape of the electrode assembly by adjusting the longitudinal extension or withdrawal of the expander.

Referring now to <FIG> and <FIG>, catheter body <NUM> further comprises irrigation ports <NUM> and <NUM> configured to supply a suitable irrigation fluid, such as heparinized saline, to electrode assembly <NUM>. Irrigation port <NUM> receives irrigation fluid via irrigation lumen <NUM>. Lumen <NUM> extends from handle <NUM> and terminates at the distal end of catheter body <NUM>. In this embodiment, port <NUM> supplies irrigation fluid to the proximal end of irrigated electrode assembly <NUM>. At this location, the proximal ends of spines <NUM> are slightly separated leaving small gaps between each pair when the device is deployed. Fluid exiting port <NUM> flushes this area to reduce thrombus formation.

Irrigation port <NUM> receives irrigation fluid from irrigation lumen <NUM>. In this embodiment, expander <NUM> includes a central lumen that is in fluid communication with an irrigation fluid supply in handle <NUM> and a distal end that terminates at irrigation port <NUM>. Irrigation port <NUM> supplies irrigation fluid to the region surrounding distal cap <NUM>. At this location, the plurality of spines <NUM> are also close together as at their proximal ends, but each spine has a concave shape adjacent to where it is attached to distal cap <NUM>. This concave shape may increase thrombus formation. Irrigation fluid from irrigation port <NUM> flushes this area to reduce this risk.

As shown in <FIG>, when the basket-shaped electrode assembly <NUM> assumes the expanded configuration, spines <NUM> bow outwards into contract or closer proximity with the walls of the chamber in which it has been deployed, such as the left atrium. Correspondingly, relative movement of expander <NUM> in the distal direction lengthens the distance between the distal and proximal ends of spines <NUM>, causing them to assume a generally linear configuration in line with the catheter body <NUM> to minimize their outer diameter for insertion within and withdrawal from the patient.

In one aspect, an electrophysiologist may introduce a guiding sheath, guidewire and dilator into the patient, as is generally known in the art. As an example, a suitable guiding sheath for use in connection with the inventive catheter is a <NUM> french DiRex™ Guiding Sheath (commercially available from BARD, Murray Hill, NJ). The guidewire is inserted, the dilator is removed, and the catheter is introduced through the guiding sheath whereby the guidewire lumen in the expander permits the catheter to pass over the guidewire. In one exemplary procedure as depicted in <FIG>, the catheter is first introduced to the right atrium (RA) via the inferior vena cava (IVC), where it passes through the septum (S) in order to reach the left atrium (LA).

As will be appreciated, the guiding sheath covers the spines <NUM> of the basket-shaped electrode assembly <NUM> in a collapsed position so that the entire catheter can be passed through the patient's vasculature to the desired location. The expander <NUM> may be positioned distally of the catheter body to allow the spines of the assembly to be flattened while the assembly is passed through the guiding sheath. Once the distal end of the catheter reaches the desired location, e.g., the left atrium, the guiding sheath is withdrawn to expose the basket-shaped electrode assembly <NUM>. The expander <NUM> is drawn proximally or otherwise manipulated so that the spines <NUM> flex outwardly between the distal and proximal junctions. With the basket-shaped electrode assembly <NUM> radially expanded, the ring electrodes <NUM> contact atrial tissue. As recognized by one skilled in the art, the basket-shaped electrode assembly <NUM> may be fully or partially expanded, straight or deflected, in a variety of configurations depending on the configuration of the region of the heart being mapped.

When the basket-shaped electrode assembly <NUM> is expanded, the electrophysiologist may map local activation time and/or ablate using electrodes <NUM>, which can guide the electrophysiologist in diagnosing and providing therapy to the patient. The catheter may include one or more reference ring electrodes mounted on the catheter body and/or one or more reference electrodes may be placed outside the body of the patient. By using the catheter with the multiple electrodes on the basket-shaped electrode assembly, the electrophysiologist can obtain a true anatomy of a cavernous region of the heart, including an atrium, allowing a more rapid mapping of the region.

As used herein, the term "basket-shaped" in describing the irrigated electrode assembly <NUM> is not limited to the depicted configuration, but can include other designs, such as spherical or egg-shaped designs, that include a plurality of expandable arms or spines connected, directly or indirectly, at their proximal and distal ends. In one aspect, the irrigated electrode assembly may include a plurality of expandable arms or spines connected, directly or indirectly, at their proximal ends only and not at their distal ends. In one aspect, different sized basket-shaped electrode assemblies may be employed depending on the patient's anatomy to provide a close fit to the area of the patient being investigated, such as the right or left atria.

A detailed view of one embodiment of the irrigated basket-shaped electrode assembly <NUM> is shown in <FIG>, featuring a total of twelve spines <NUM>, each carrying sixteen electrodes <NUM>. As noted above, in other embodiments, different numbers of spines <NUM> and/or electrodes <NUM> may be employed, each of which may be evenly or unevenly distributed as desired. The distal ends of the spines <NUM> and the expander <NUM> may be secured to a distal cap <NUM>. Correspondingly, the proximal ends of the spines <NUM> may be secured to the distal end of the catheter body <NUM>, while the expander <NUM> may be routed through lumen <NUM> of the catheter body <NUM> so that the proximal end extends to the control handle <NUM>. As described above, lumen <NUM> may also be used to supply a suitable irrigation fluid, to the basket-shaped electrode assembly <NUM>.

Each spine <NUM> may comprise a flexible wire <NUM> with a non-conductive covering <NUM> on which one or more of the ring electrodes <NUM> are mounted. In an embodiment, the flexible wires <NUM> may be formed from a shape memory material to facilitate the transition between expanded and collapsed arrangements and the non-conductive coverings <NUM> may each comprise a biocompatible plastic tubing, such as polyurethane or polyimide tubing. For example, nickel-titanium alloys known as nitinol may be used. At body temperature, nitinol wire is flexible and elastic and, like most metals, nitinol wires deform when subjected to minimal force and return to their shape in the absence of that force. Nitinol belongs to a class of materials called Shaped Memory Alloys (SMA) that have interesting mechanical properties beyond flexibility and elasticity, including shape memory and superelasticity which allow nitinol to have a "memorized shape" that is dependent on its temperature phases. The austenite phase is nitinol's stronger, higher-temperature phase, with a simple cubic crystalline structure. Superelastic behavior occurs in this phase (over a <NUM>°- <NUM> temperature spread). Correspondingly, the martensite phase is a relatively weaker, lower-temperature phase with a twinned crystalline structure. When a nitinol material is in the martensite phase, it is relatively easily deformed and will remain deformed. However, when heated above its austenite transition temperature, the nitinol material will return to its pre-deformed shape, producing the "shape memory" effect. The temperature at which nitinol starts to transform to austenite upon heating is referred to as the "As" temperature. The temperature at which nitinol has finished transforming to austenite upon heating is referred to as the "Af" temperature. Accordingly, the basket-shaped electrode assembly <NUM> may have a three dimensional shape that can be easily collapsed to be fed into a guiding sheath and then readily returned to its expanded shape memory configuration upon delivery to the desired region of the patient upon removal of the guiding sheath.

Alternatively, in some embodiments the spines <NUM> can be designed without the internal flexible wire <NUM> if a sufficiently rigid nonconductive material is used for the non-conductive covering <NUM> to permit radial expansion of the basket-shaped electrode assembly <NUM>, so long as the spine has an outer surface that is non-conductive over at least a part of its surface for mounting of the ring electrodes <NUM>. In this embodiment, each spine may include a separate irrigation lumen and port that is isolated from any wires or cabling.

A single spine <NUM> is shown in its expanded, shape memory configuration in <FIG>. In this embodiment, spine <NUM> has a middle region <NUM> having a convex shape configured to bring electrodes <NUM> into contact or close proximity with the wall of the chamber in which it has been positioned. As noted above, the flexible wire <NUM> has non-conductive covering <NUM> on which the electrodes <NUM> are positioned. A distal region <NUM> may exhibit a concave configuration, positioned generally within a radius of curvature indicated by the middle region <NUM>. This configuration provides the distal region <NUM> with a smooth transition from the flexible wire <NUM> being aligned with the longitudinal axis of catheter body <NUM> to an apex joining the middle region <NUM>. Alignment with the longitudinal axis allows for a minimized collapsed diameter, while the concave shape allows one or more electrodes <NUM> to be positioned near the apex to provide sensor coverage for the polar region adjacent the distal cap <NUM>. A proximal region <NUM> may have a concave configuration, positioned generally outside the radius of curvature indicated by the middle region <NUM>. Similarly, this configuration provides a smooth transition from the middle region <NUM> to the flexible wire again being in alignment with the longitudinal axis.

Another exemplary embodiment is shown in <FIG>. In this design, opposing spines <NUM> are formed by a continuous stretch of flexible wire <NUM> extending through apertures <NUM> configured as through holes in the generally cylindrical distal cap <NUM>. Apertures <NUM> may be offset in a helical pattern as shown or in any other suitable manner to accommodate each loop of flexible wire <NUM> without interference from each other. As will be appreciated, the position of each spine may be stabilized with respect to its opposing spine since they are formed from a single piece of wire.

In a further aspect, each spine <NUM> may include cabling <NUM> with built-in or embedded lead wires <NUM> for the electrodes <NUM> carried by the spine as shown in <FIG>. The cabling has a core <NUM>, and a plurality of generally similar wires <NUM> each covered by an insulating layer <NUM> that enables each wire to be formed and to function as a conductor <NUM>. The core <NUM> provides a lumen <NUM> in which can pass other components such as a support structure in the form of flexible wire <NUM> and/or additional lead wire(s), cables, tubing or other components.

In one embodiment, flexible wire <NUM>' is positioned within lumen <NUM>. In this embodiment, at least one of the flexible wires <NUM>' has been modified to include a central irrigation lumen <NUM> to supply a suitable irrigation fluid to irrigated electrode assembly <NUM> through at least one irrigation port <NUM>. As illustrated in <FIG>, each flexible wire <NUM>' includes an irrigation lumen <NUM> and at least one irrigation port <NUM>. In one embodiment, each flexible wire comprises at least one irrigation port <NUM> located along the flexible wire. As will be described in greater detail below, each irrigation port <NUM> may be a dedicated port or may be integrated into an electrode, such as by employing a perforated electrode, or a combination of these designs may be used.

In one embodiment, the ports are located at an apex. In the same or another embodiment, the irrigation port <NUM> is located along flexible wire <NUM>' adjacent the distal cap <NUM>. One of skill in the art will recognize that the number and location of the irrigation ports <NUM> can vary depending on the configuration of the assembly <NUM>. The irrigation ports may be disposed along the length of flexible wire <NUM>', from the proximal end adjacent the distal end of catheter body <NUM> to the distal hub <NUM>. In each of these embodiments, the location of the ports is such as to supply an adequate amount of irrigation fluid to flush the area and prevent thrombus formation.

In another embodiment, in addition to irrigated electrode assembly <NUM> having irrigation ports <NUM> disposed on flexible wires <NUM>', catheter body <NUM> further includes irrigation port <NUM> at a distal end of the catheter. In another embodiment, irrigation port <NUM> and associated irrigation lumen <NUM> may also be included in the catheter design.

One of skill in the art will appreciate that the pressure of the irrigation fluid may change, (i.e.) increase, as the fluid moves from a larger lumen to a smaller lumen within the flexible wire <NUM>'. In one embodiment, the handle <NUM> may include a fluid control valve (not shown) to adjust this increased pressure to a more suitable lower pressure and flow rate. The pressure and flow rate may also be regulated using an adjustable pump external to the catheter.

In the following description, generally similar components associated with cabling <NUM> are referred to generically by their identifying component numeral, and are differentiated from each other, as necessary, by appending a letter A, B,. to the numeral. Thus, wire 42C is formed as conductor 48C covered by insulating layer 46C. While embodiments of the cabling may be implemented with substantially any plurality of wires <NUM> in the cabling, for clarity and simplicity in the following description cabling <NUM> is assumed to comprise N wires 42A, 42B, 42C,. 42N, where N equals at least the number of ring electrodes on each respective spine <NUM> of the basket-shaped electrode assembly <NUM>. For purposes of illustration, insulating layers <NUM> of wires <NUM> have been drawn as having approximately the same dimensions as conductors <NUM>. In practice, the insulating layer is typically approximately one-tenth the diameter of the wire.

The wires <NUM> are formed over an internal core <NUM>, which is typically shaped as a cylindrical tube. The core material is typically selected to be a thermoplastic elastomer such as a polyether block amide or PEBAX®. Wires <NUM> are formed on an outer surface <NUM> of the core <NUM> by coiling the wires around the tube. In coiling wires <NUM> on the surface <NUM>, the wires are arranged so that they contact each other in a "close-packed" configuration. Thus, in the case that core <NUM> is cylindrical, each wire <NUM> on the outer surface is in the form of a helical coil, configured in a multi-start thread configuration. For example, in the case of the N wires <NUM> assumed herein, wires <NUM> are arranged in an N-start thread configuration around core <NUM>.

In contrast to a braid, all helical coils of wires <NUM> herein have the same handedness (direction of coiling). Moreover, wires in braids surrounding a cylinder are interleaved, so are not in the form of helices. Because of the non-helical nature of the wires in braids, even braid wires with the same handedness do not have a threaded form, let alone a multi-start thread configuration. Furthermore, because of the lack of interleaving in arrangements of wires in embodiments of the cabling, the overall diameter of the cabling produced is less than that of cabling using a braid, and the reduced diameter is particularly beneficial when the cabling is used for a catheter.

Once wires <NUM> have been formed in the multi-start thread configuration described above, the wires are covered with a protective sheath, such as in the form of the non-conductive covering <NUM> described above. The protective sheath material is typically selected to be a thermoplastic elastomer such as for example, 55D PEBAX without additives so that it is transparent. In that regard, the insulating layer <NUM> of at least one of wires <NUM> may be colored differently from the colors of the remaining wires as an aid in identifying and distinguishing the different wires.

The process of coiling wires <NUM> around the core <NUM>, and then covering the wires by the non-conductive covering <NUM> essentially embeds the wires within a wall of cabling <NUM>, the wall comprising the core and the sheath. Embedding the wires within a wall means that the wires are not subject to mechanical damage when the cabling is used to form a catheter. Mechanical damage is prevalent for small wires, such as 48AWG wires, if the wires are left loose during assembly of a catheter.

In use as a catheter, an approximately cylindrical volume or lumen <NUM> enclosed by the core <NUM>, that is afforded by embedding smaller wires (such as the <NUM> AWG wires) in the wall, allows at least a portion of the lumen <NUM> to be used for other components. It is understood that the plurality of wires <NUM> shown in the drawings is representative only and that a suitable cabling provides at least a plurality of wires equal to or greater than the plurality of ring electrodes mounted on each cabling or spine of the assembly. Cabling suitable for use with the present invention is described in <CIT>, entitled HIGH DENSITY ELECTRODE STRUCTURE, and <CIT>, entitled CONNECTION OF ELECTRODES TO WIRES COILED ON A CORE. Each cabling <NUM> (with embedded lead wires <NUM>) may extend to the control handle <NUM> for suitable electrical connection of wires <NUM>, thereby allowing signals measured by electrodes <NUM> to be detected.

As noted, each spine <NUM> and cabling <NUM> pair carries a plurality of ring electrodes <NUM>, which may be configured as monopolar or bipolar, as known in the art. Cabling <NUM> is schematically shown by a top view in <FIG> and by a side view in <FIG>, in which portions of non-conductive covering <NUM> have been cut away to expose wires <NUM> of the cabling <NUM>, as well as to illustrate the attachment of a ring electrode <NUM> to the cabling <NUM>. <FIG> illustrates cabling <NUM> prior to attachment of electrode <NUM>, while <FIG> illustrates the cabling after the ring electrode has been attached. The ring electrodes <NUM> may have suitable dimensions to allow them to be slid over sheath <NUM>.

The attachment point for each electrode <NUM> may be positioned over one or more of the wires <NUM>, such as wire 42E in the illustrated example. A section of non-conductive covering <NUM> above the wire 42E and a corresponding section of insulating layer 46E are removed to provide a passage <NUM> to conductor 48E. In a disclosed embodiment, conductive cement <NUM> may be fed into the passage, ring electrode <NUM> may then be slid into contact with the cement, and finally the electrode may be crimped in place. Alternatively, the ring electrode <NUM> may be attached to a specific wire <NUM> by pulling the wire through non-conductive covering <NUM>, and resistance welding or soldering the ring electrode to the wire.

In another embodiment, the irrigated electrode assembly may employ a different configuration, such as the multi-spine assembly shown in <FIG>. In this embodiment, the irrigated electrode assembly <NUM> may include a plurality of expandable spines <NUM> connected, directly or indirectly, at their proximal ends only and not at their distal ends. Catheter <NUM> comprises an elongated catheter body <NUM> having proximal and distal ends, a control handle <NUM> at the proximal end of the catheter body <NUM>, and an irrigated electrode assembly <NUM> having a plurality of spines <NUM>, having free distal ends and secured at their proximal end to catheter body <NUM>. Catheter body <NUM> may further comprise irrigation port <NUM> configured to supply a suitable irrigation fluid, such as heparinized saline, to electrode assembly <NUM>. Irrigation port <NUM> receives irrigation fluid via irrigation lumen <NUM>. Lumen <NUM> extends from handle <NUM> and terminates at the distal end of catheter body <NUM>. In this embodiment, irrigation port <NUM> supplies irrigation fluid to the proximal end of the irrigated electrode assembly <NUM>. At this location, the proximal ends of spines <NUM> are slightly separated leaving small gaps between each pair when the device is deployed. Fluid exiting port <NUM> flushes this area to reduce thrombus formation.

Although <FIG> shows the use of irrigation port <NUM>, it is not required for the operation of the device. In an embodiment, each spine may have multiple electrodes <NUM>, which may be configured as diagnostic electrodes, ablation electrodes or both, and at least one irrigation port <NUM> on at least one spine. As will be described in greater detail below, each irrigation port <NUM> may be a dedicated port or may be integrated into an electrode, such as by employing a perforated electrode, or a combination of these designs may be used. In some embodiments as shown, each spine <NUM> may have more than one irrigation port <NUM>, and may be provided at any location along the spine. When a spine <NUM> has multiple irrigation ports <NUM>, they may be arranged in any distribution along the spine, including evenly or skewed to the proximal or distal ends or to the middle of the spine. Irrigation ports <NUM> are distributed evenly across irrigated electrode assembly <NUM>.

Each spine <NUM> may have a lumen (not shown in this view for the sake of clarity) that is in fluid communication with irrigation ports <NUM>. Correspondingly, each spine lumen may be in communication with an irrigation lumen <NUM> provided in catheter body <NUM> that may be used to supply a suitable irrigation fluid, such as heparinized saline, to the irrigated electrode assembly <NUM>. A fitting <NUM> in the control handle <NUM> may be provided to conduct irrigation fluid from a suitable source or pump into the lumen <NUM>.

Additionally, one or more location sensors <NUM> may be provided near a distal end of the catheter <NUM> adjacent the irrigated electrode assembly <NUM> as schematically indicated in <FIG>. The sensor(s) may each comprise a magnetic-field-responsive coil or a plurality of such coils. Using a plurality of coils enables six-dimensional position and orientation coordinates to be determined. The sensors may therefore generate electrical position signals in response to the magnetic fields from external coils to enable a position determination (e.g., the location and orientation) of the distal end of catheter <NUM> within the heart cavity to be made.

Exemplary details of aspects of spines <NUM> are shown in the detail view of <FIG>. As shown, spine <NUM> may include a lumen <NUM> that is in communication with irrigation lumen <NUM>. If desired, each spine lumen <NUM> may include a controllable valve so that irrigation fluid may be fed to selected portions of irrigated electrode assembly <NUM>. The irrigation ports are also in communication with lumen <NUM>. As noted above, the irrigation ports may be a dedicated port <NUM> and/or may be integrated into an electrode <NUM>, having a plurality of perforations <NUM>. Spine <NUM> may comprise a flexible, resilient core <NUM> with a non-conductive covering <NUM> that may also define lumen <NUM>. In an embodiment, core <NUM> may be formed from a shape memory material as noted above to facilitate the transition between expanded and collapsed arrangements. The non-conductive covering <NUM> may comprise a biocompatible plastic tubing, such as polyurethane or polyimide tubing.

To help illustrate use of the electrode assembly <NUM>, <FIG> is a schematic depiction of an invasive medical procedure, according to an embodiment of the present invention. Catheter <NUM>, with the basket-shaped electrode assembly <NUM> (not shown in this view) at the distal end may have a connector <NUM> at the proximal end for coupling the wires <NUM> from their respective electrodes <NUM> (neither shown in this view) to a console <NUM> for recording and analyzing the signals they detect. An electrophysiologist <NUM> may insert the catheter <NUM> into a patient <NUM> in order to acquire electropotential signals from the heart <NUM> of the patient. The professional uses the control handle <NUM> attached to the catheter in order to perform the insertion. The professional also uses control handle <NUM> to adjust the continuous flow of irrigation fluid through irrigated electrode assembly <NUM> in order to prevent thrombus formation. Console <NUM> may include a processing unit <NUM> which analyzes the received signals, and which may present results of the analysis on a display <NUM> attached to the console. The results are typically in the form of a map, numerical displays, and/or graphs derived from the signals.

In a further aspect, the processing unit <NUM> may also receive signals from one or more location sensors <NUM> provided near a distal end of the catheter <NUM> adjacent the basket-shaped electrode assembly <NUM> as schematically indicated in <FIG>. The sensor(s) may each comprise a magnetic-field-responsive coil or a plurality of such coils. Using a plurality of coils enables six-dimensional position and orientation coordinates to be determined. The sensors may therefore generate electrical position signals in response to the magnetic fields from external coils, thereby enabling processor <NUM> to determine the position, (e.g., the location and orientation) of the distal end of catheter <NUM> within the heart cavity. The electrophysiologist may then view the position of the basket-shaped electrode assembly <NUM> on an image the patient's heart on the display <NUM>. By way of example, this method of position sensing may be implemented using the CARTO™ system, produced by Biosense Webster Inc. (Diamond Bar, Calif. ) and is described in detail in <CIT>, <CIT>, <CIT>, <CIT>,<CIT> and<CIT>, in <CIT>, and in <CIT>, <CIT> and <CIT>. As will be appreciated, other location sensing techniques may also be employed. If desired, at least two location sensors may be positioned proximally and distally of the basket-shaped electrode assembly <NUM>. The coordinates of the distal sensor relative to the proximal sensor may be determined and, with other known information pertaining to the curvature of the spines <NUM> of the basket-shaped electrode assembly <NUM>, used to find the positions of each of the electrodes <NUM>.

Claim 1:
A catheter (<NUM>) comprising an elongated catheter body (<NUM>) having proximal and distal ends and at least one irrigation lumen (<NUM>) therethrough and an irrigated electrode assembly (<NUM>) at the distal end of the catheter body, the irrigated electrode assembly comprising a plurality of spines (<NUM>) connected at their proximal ends, each spine comprising a plurality of electrodes (<NUM>), and
wherein each spine further comprises a spine lumen (<NUM>) and a plurality of irrigation ports (<NUM>) in fluid communication with the spine lumen, wherein each spine lumen is in fluid communication with the irrigation lumen, wherein the irrigation ports comprise a combination of dedicated irrigation ports and integrated irrigation ports wherein each integrated irrigation port is integrated with one of the plurality of electrodes, the electrode having a plurality of perforations (<NUM>), and
wherein the irrigation ports are distributed evenly across the irrigated electrode assembly.