US20150011991A1

US20150011991A1 - Electrode Assembly For Catheter System

Info

Publication number: US20150011991A1
Application number: US14/258,398
Authority: US
Inventors: John Jason Buysman; Gregory James Dakin
Original assignee: St Jude Medical Cardiology Division Inc
Current assignee: St Jude Medical Cardiology Division Inc
Priority date: 2013-07-03
Filing date: 2014-04-22
Publication date: 2015-01-08
Also published as: US11272981B2; US20220168042A1; US20180303546A1

Abstract

In an electrode assembly for a catheter system, a plurality of struts extends from a proximal end to a distal end of the electrode assembly. Each strut has a longitudinally extending proximal leg, a longitudinally extending distal leg, and a center segment extending between and interconnecting the proximal leg and the distal leg. A hinge interconnects the proximal leg and the center segment, and another hinge interconnects the distal leg and the center segment. The center segment of each of the struts has a corresponding electrode thereon. The electrode assembly is configurable between a collapsed configuration and an expanded configuration, with the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to provisional application Ser. No. 61/842,646 filed Jul. 3, 2013, the entire specification of which is incorporated herein.

BACKGROUND OF THE DISCLOSURE

A. Field of the disclosure
The present disclosure relates generally to a catheter system for use in a human body, and more particularly to a multi-electrode catheter system, and even more particularly to an electrode assembly for a multi-electrode catheter system.
B. Background Art
Catheter systems are well known in the art for use in medical procedures, such as diagnostic, therapeutic and ablative procedures. Typical catheter systems generally include an elongate catheter extending from a handle. A physician manipulates the catheter through the patient's vasculature to an intended site within the patient. The catheter typically carries one or more working components, such as electrodes or other diagnostic, therapeutic or ablative devices for carrying out the procedures. One or more controls or actuators may be provided on the handle for selectively adjusting one or more characteristics of the working components.
One particular example of a multi-electrode catheter system is an ablative catheter system in which the working component is a multi-electrode component carried at the distal end of a flexible catheter. A control wire extends within the catheter from the multi-electrode component to the handle to operatively connect the multi-electrode component to an actuator on the handle. Manipulating the actuator acts on the control wire to configure the multi-electrode component into a desired configuration for carrying out the ablative procedure. For example, in one such ablative catheter system made by St. Jude Medical, Inc. under the trade name EnligHTN, the multi-electrode component is an electrode assembly in the general form of a basket. Upon locating the electrode basket at a desired location within the patient, manipulating the actuator associated with the handle pulls on the control wire to reconfigure the electrode basket from a collapsed configuration to an expanded configuration in which the electrodes are intended to be in apposition with a surface, such as an arterial wall of the patient. It is thus desirable to facilitate apposition of as many of the electrodes of the electrode basket as possible against the arterial wall of the patient when the electrode basket is expanded to achieve optimal performance of the multi-electrode catheter system.

BRIEF SUMMARY OF THE DISCLOSURE

In one embodiment, an electrode assembly for an electrode catheter system generally comprises first and second struts each extending from a proximal end to a distal end of the electrode assembly and having a corresponding electrode disposed thereon intermediate the proximal and distal ends of the electrode assembly. The electrode assembly is configurable between a collapsed configuration and an expanded configuration, with the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration. In the collapsed configuration, the electrode on the first strut is at a first longitudinal position intermediate the proximal and distal ends of the electrode assembly and the electrode on the second strut is at a second longitudinal position intermediate the proximal and distal ends of the electrode assembly and different from the first longitudinal position of the electrode on the first strut. In the expanded configuration, the first longitudinal position of the electrode on the first strut is substantially equal to the second longitudinal position of the electrode on the second strut.
In another embodiment, an electrode assembly for an electrode catheter system generally comprises a plurality of struts each extending from a proximal end to a distal end of the electrode assembly. Each strut has a longitudinally extending proximal leg, a longitudinally extending distal leg, and a center segment extending between and interconnecting the proximal leg and the distal leg. The proximal leg and the distal leg of at least one of the struts has a corresponding stiffness, and the center segment of the at least one of the struts has a stiffness greater than the stiffness of each of the proximal leg and the distal leg of the at least one of the struts. The center segment of each of the struts has a corresponding electrode thereon. The electrode assembly is configurable between a collapsed configuration and an expanded configuration, with the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration.
In yet another embodiment, an electrode assembly for an electrode catheter system generally comprises a plurality of struts each extending from a proximal end to a distal end of the electrode assembly. Each strut has a longitudinally extending proximal leg, a longitudinally extending distal leg, and a center segment extending between and interconnecting the proximal leg and the distal leg. The center segment of each of the struts has a corresponding electrode thereon. The electrode assembly is configurable between a collapsed configuration and an expanded configuration, with the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration.
In still another embodiment, an electrode assembly for an electrode catheter system generally comprises a plurality of struts each extending from a proximal end to a distal end of the electrode assembly. Each strut has a riser element disposed thereon intermediate the proximal end and the distal end of the electrode assembly. The electrode assembly is configurable between a collapsed configuration and an expanded configuration. In the expanded configuration the riser element of each strut extends transversely outward from the longitudinal axis of the electrode assembly a greater distance than any other point along the respective strut, with each strut further having an electrode disposed on the respective riser element.
In still another embodiment, an electrode assembly for an electrode catheter system generally comprises a plurality of struts each extending from a proximal end to a distal end of the electrode assembly and each having a corresponding electrode thereon. The electrode assembly is configurable between a collapsed configuration and an expanded configuration, with the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration. In the collapsed configuration at least one of the struts has a generally concave segment extending lengthwise along the strut intermediate the proximal and distal ends of the electrode assembly.
The foregoing and other aspects, features, details, utilities and advantages of the present disclosure will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a catheter system including a handle, a catheter and an electrode assembly having multiple electrodes, with the electrode assembly being in what is referenced herein as a collapsed configuration.

FIG. 2 is a side elevation of the catheter system of FIG. 1, with the electrode assembly being in what is referenced herein as an expanded configuration resulting from rotation of a rotatable actuator.

FIG. 3 is a perspective view of the electrode assembly of FIG. 1 with a plurality of struts carrying the multiple electrodes, the electrode assembly being in its collapsed configuration.

FIG. 4 is a longitudinal cross-section of the electrode assembly of FIG. 3.

FIG. 5 is a perspective view of the electrode assembly similar to FIG. 3 but illustrating the electrode assembly in its expanded configuration.

FIG. 6 is an enlarged perspective view of a distal end of the electrode assembly of FIG. 3.

FIG. 7 is an enlarged perspective view of a proximal end of the electrode assembly of FIG. 3.

FIG. 8 is an enlarged top plan view of another embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 9 is an enlarged top plan view of a third embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 10 is an enlarged top plan view of a fourth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 11 is an enlarged top plan view of a fifth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 12 is an enlarged top plan view of a sixth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 13 is an enlarged top plan view of a seventh embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 14 is an enlarged top plan view of an eighth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 15 is an enlarged top plan view of a ninth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 16 is an enlarged top plan view of a tenth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 17 is an enlarged top plan view of an eleventh embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 18 is an enlarged top plan view of a twelfth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 19 is an enlarged top plan view of a thirteenth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 20 is an enlarged top plan view of a fourteenth embodiment of a hinge suitable for use with the electrode assembly of FIG. 3.

FIG. 21 is a schematic view of the electrode assembly of FIG. 3 at one stage of manufacturing thereof at which the electrode assembly is in the form of a tube, with the tube being in a longitudinally opened and laid flat orientation for illustrative purposes.

FIG. 22 is a transverse cross-section taken through a center segment of one strut of the electrode assembly of FIG. 3.

FIG. 23 is a transverse cross-section taken through a center segment of another embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 24 is a transverse cross-section taken through a center segment of a third embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 25 is a transverse cross-section taken through a center segment of a fourth embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 26 is a transverse cross-section taken through a center segment of a fifth embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 27 is a transverse cross-section taken through a center segment of a sixth embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 28 is a transverse cross-section taken through a center segment of a seventh embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 29 is a transverse cross-section taken through a center segment of an eighth embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 30 is a transverse cross-section taken through a center segment of a ninth embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 31 is a transverse cross-section taken through a center segment of a tenth embodiment of a strut suitable for use with the electrode assembly of FIG. 3.

FIG. 32 is side elevation of a second embodiment of an electrode assembly, having a pair of struts, with the electrode assembly being illustrated in its collapsed configuration.

FIG. 33 is a side elevation of the electrode assembly of FIG. 32 illustrated in its expanded configuration.

FIG. 34 is a side elevation of a third embodiment of an electrode assembly, having a pair of struts, with the electrode assembly being illustrated in its collapsed configuration.

FIG. 35 is a side elevation of the electrode assembly of FIG. 34 illustrated in its expanded configuration.

FIG. 36 is a side elevation of a fourth embodiment of an electrode assembly, having a pair of struts, with the electrode assembly being illustrated in its collapsed configuration.

FIG. 37 is a side elevation of a fifth embodiment of an electrode assembly, having a pair of struts, with the electrode assembly being illustrated in its collapsed configuration.

FIG. 38 is a side elevation of a sixth embodiment of an electrode assembly, having a pair of struts, with the electrode assembly being illustrated in its collapsed configuration.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring now to the drawings, and in particular to FIGS. 1 and 2, one embodiment of a catheter system 21 includes a flexible catheter 23, a handle 25 to which the catheter is connected, and a conductor assembly 27 for electrically connecting the catheter system to a suitable power supply (not shown). As one example, the catheter system 21 illustrated and described herein is suitably constructed for use as an ablation system, such as a renal or heart ablation system. More particularly, the illustrated catheter system 21 is a multi-electrode renal denervation system. One example of such a catheter system 21 is currently made by St. Jude Medical, Inc. under the trade name EnligHTN. General operation of a multi-electrode renal denervation system is known to those of skill in the art and is not described further herein except to the extent necessary to describe the present embodiments. It is also understood that the catheter system 21 may be used for any other suitable treatment or purpose without departing from the scope of this disclosure. Additionally, while the catheter system 21 is illustrated and described herein as including a flexible catheter 23, the system may further include other components used, for example, to guide the flexible catheter into the patient—such as, without limitation, a relatively more rigid guide catheter (not shown), or an over-the-wire system (not shown).
The catheter 23 includes an elongate, flexible hollow shaft 29 connected to the handle 25 at or near a proximal or rear end of the catheter shaft (not shown because it is hidden by a connector at the front end of the handle 25), and an electrode assembly 33 disposed at or near a distal or front end 35 of the catheter shaft. It is understood, however, that the electrode assembly 33 may be disposed anywhere along the catheter shaft 29 intermediate the proximal end and the distal end 35 thereof without departing from the scope of this disclosure. As used herein, the terms proximal and front, and distal and rear, are used with reference to the orientation of the catheter system 21 illustrated in the various drawings and for the purpose of describing the various embodiments set forth herein, and are not intended as limiting the catheter system and related components to having any particular orientation upon assembly or during operation thereof. In particular, the terms proximal and rear refer to a longitudinal position that is relatively nearer to the handle 25 while the terms distal and front refer to a longitudinal position that is relatively farther from the handle.
The illustrated electrode assembly 33 is in the form of what may be referred to as an electrode basket and is suitably configurable between a collapsed configuration (FIGS. 1 and 3) for maneuvering and positioning the electrode assembly in the patient, and an expanded configuration (FIGS. 2 and 5) for operation of the electrode assembly to perform a desired procedure such as an ablation procedure. An annular (e.g., ring-shaped) actuator 37 is mounted on the handle 25 for rotation relative thereto and is operatively connected to the electrode assembly 33 for selectively configuring the electrode assembly between its collapsed and expanded configurations. It is understood that another suitable actuator (e.g., slide, push button, lever, etc.) may be used instead of the rotating actuator 37 to selectively configure the electrode assembly 33 without departing from the scope of this disclosure. In some embodiments, the electrode assembly 33 may be selectively adjustable between an infinite number of configurations (e.g., degrees of expansion) between its collapsed and expanded configurations using the actuator 37.
A control line, such as a suitable cable or pull wire 41 (FIGS. 3 and 4) extends from the electrode assembly 33 within the hollow catheter shaft 29 and into the handle 25 for operative connection with the actuator to thereby operatively connect the actuator 37 with the electrode assembly. In some embodiments, two or more pull wires, cables or other suitable control lines may be used for selectively configuring the electrode assembly 33. It is also understood that the control line 41 may be any suitable control line other than a pull wire, such as a cable, string, tie, compression member or other suitable control to operatively connect the electrode assembly 33 to the actuator 37. In other embodiments, any suitable conventional manner for actuating or otherwise selectively configuring the electrode assembly 33 may be used. A suitable twisted electrical wire bundle (not shown) also extends through the hollow catheter shaft 29 from the handle to the electrode assembly to deliver power to the electrode assembly.
With reference now to FIG. 3, the electrode assembly 33 has a proximal end 51 at which the assembly is connected to the catheter shaft 29 (e.g., to the distal end 35 of the catheter shaft in the embodiment of FIGS. 1 and 2), a distal end 53 that in the illustrated embodiment also defines a distal end, or tip, of the catheter 23, and a longitudinal axis X. The illustrated electrode assembly 33 comprises a set of four struts 55 a-d, extending coextensively with each other from the proximal end 51 to the distal end 53 of the electrode assembly in circumferentially equal spaced relationship with each other about the longitudinal axis X of the electrode assembly. In other embodiments, the electrode assembly 33 may comprise more or less than four struts 55 a-d (see, e.g., the embodiments of FIGS. 32-38) without departing from the scope of this disclosure. It is also contemplated that the struts 55 a-d may be other than equally spaced from each other circumferentially, and/or the struts may be other than coextensive with each other, and remain within the scope of this disclosure.
Each of the struts 55 a-d carries at least one electrode 57 disposed at a respective longitudinal position along the strut, i.e., at a respective longitudinal distance along the longitudinal axis X from the proximal end of the electrode assembly. In the embodiment of FIG. 3, each of the electrodes 57 is at a different longitudinal position. It is understood that the electrodes 57 may be at longitudinal positions other than those shown in FIG. 3. In other embodiments, two, three or all of the electrodes 57 may instead be at the same longitudinal position. It is also understood that multiple electrodes 57 may be carried by any one or all of the struts 55 a-d, e.g., with the electrodes on any given strut spaced longitudinally from each other along the strut. While not shown in FIG. 3, a respective suitable sheathing or sleeve, constructed of a polymeric material, circumferentially encloses each of the struts 55 a-d along their respective lengths. The segment of the control line 41 that extends from the proximal end to the distal end of the electrode assembly may likewise be circumferentially enclosed by a suitable polymeric sheathing or sleeve.
At the distal end 53 of the electrode assembly 33, the struts 55 a-d terminate at, and in one embodiment for making the electrode assembly are formed integrally with, a connecting ring 61 (as best illustrated in FIGS. 4 and 6) having a central opening 63 that is coaxial with the longitudinal axis X of the electrode assembly. In the illustrated embodiment, multiple holes 65 are formed in the sidewall of the connecting ring 61 in spaced relationship with each other about the circumference of the connecting ring and are open to the central opening 63 of the connector. In other embodiments, however, the holes 65 may be omitted. Suitable polymeric sheathing (not shown) may surround the connecting ring 61 to cover the holes 65 following assembly of the electrode assembly 33. A blunt tip 67 includes a rounded head 71 having a cylindrical body 69 extending longitudinally therefrom and being generally hollow along its length such that the rounded head closes the distal end of the body.
The control line 41 extends generally along the longitudinal axis X of the electrode assembly 33 through the body 69 of the tip 67 where it is secured to the tip by braising, adhesive, welding, soldering or other suitable securement technique. The tip body 69 is sized in transverse cross-section, e.g., outer diameter, to be received through and seated within the central opening 63 of the connecting ring 61 with the head 71 of the tip 67 abutting against the end of the connecting ring as seen in FIGS. 4 and 6. The holes 65 spaced about the circumference of the connecting ring 61 allow a suitable adhesive to be supplied through the holes for securing the tip 67 on the connecting ring—thereby connecting the distal end 53 of the electrode assembly 33 to the control line 41 for operative connection with the actuator 37 on the handle 25. In other embodiments, the struts 55 a-d may be retained at the distal end 53 of the electrode assembly 33 in another suitable manner and remain within the scope of this disclosure. It is also contemplated that the struts 55 a-d and connecting ring 61 may be formed separate from each other and subsequently secured together by any suitable securement technique.
Referring to FIGS. 4 and 7, at the proximal end 51 of the electrode assembly 33, longitudinal end segments 59 of the struts 55 a-d are connected to the catheter shaft 29 by a suitable bushing 81. The bushing 81 includes a tubular cylindrical body 83 having a central opening 85 through which the control line 41 extends from the catheter shaft 29 to the electrode assembly 33. An annular flange 87 extends radially outward from the longitudinally outer end of the bushing 81. The flange 87 has four slots 89 (corresponding to the respective longitudinal end segments 59 of the struts 55 a-d) extending longitudinally therethrough radially outward of the cylindrical body 83 of the bushing 81 and in circumferentially spaced relationship with each other. The longitudinal end segments 59 of the struts 55 a-d extend through the respective slots 89 and along the outer surface of the cylindrical body 83 of the bushing 81.
The body 83 of the bushing 81 (along with the longitudinal end segments 59 of the struts 55 a-d) is fitted with a polyimide sleeve 91 filled with suitable adhesive to secure the sleeve and longitudinal end segments of the struts to the bushing. The bushing 81, struts 55 a-d and polyimide sleeve 91 are inserted into the distal end 35 of the hollow catheter shaft 29 and secured to the catheter shaft by suitable adhesive to secure the proximal end 51 of the electrode assembly 33 to the distal end of the catheter shaft. It is understood that the struts 55 a-d may be connected to the catheter shaft 29 by any other suitable connection that allows the electrode assembly 33 to function in the manner described herein.
The electrode assembly 33 thus has a length defined by the distance along the longitudinal axis X from the proximal end 51 to the distal end 53 of the electrode assembly. To configure the electrode assembly 33 from its collapsed configuration (e.g., as illustrated in FIGS. 1 and 3) to its expanded configuration (e.g., as illustrated in FIGS. 2 and 5), rotation of the actuator 37 relative to the handle 25 operatively pulls on the control wire 41 to thereby pull the tip (i.e., the distal end 53) of the electrode assembly toward the proximal end 51 of the electrode assembly along the longitudinal axis X thereof. As the distance between the distal end 53 and the proximal end 51 of the electrode assembly 33 is shortened (i.e., as the length of the electrode assembly decreases), the struts 55 a-d are longitudinally compressed and thus forced to bend, or flex transversely outward away from the longitudinal axis X of the electrode assembly to form the expanded configuration of the electrode assembly. As used herein, the expanded configuration of the electrode assembly refers to any transverse movement of the struts 55 a-d outward from the collapsed (e.g., initial or pre-set) configuration of the electrode assembly, and may be variably adjusted. Accordingly, it is understood that in the expanded configuration the electrode assembly 33 may be expanded more or less than as illustrated in the various embodiments herein. It is also understood that the collapsed configuration is not intended to mean the most compressed form in which the electrode assembly 33 may be configured, but rather it refers to the relaxed configuration of the electrode assembly free from any external compression forces (such as when compressed to fit the electrode assembly into a guide tube or lumen).
FIG. 21 illustrates one embodiment of a method for making the electrode assembly 33 of FIGS. 1-7. A unitary tube 121 of a material having sufficient strength and shape memory characteristics, such as Nitinol™, is used. The material or materials from which the tube 121 is constructed, however, may be any other suitable material and remain within the scope of this disclosure. In FIG. 21, the tube 121 is cut lengthwise and laid flat for illustrative purposes. The desired pattern of struts 55 a-d is laser cut into the tube 121. As illustrated in FIG. 21, the tube 121 is initially longer than the length of the finished electrode assembly 33 (as illustrated, e.g., in FIG. 3). An alignment member 123 is formed on each strut 55 a-d during the laser cutting process longitudinally outward of the ends of the struts near what eventually becomes the proximal end 51 of the electrode assembly 33.
Once the struts 55 a-d are formed in the tube 121, an initial slight amount of preset expansion is formed in the tube 121 as illustrated in FIG. 3 using an internal and external die assembly or other suitable technique and then heat setting the tube to give the tube shape its collapsed (e.g., initial or preset) configuration. Such preset gives the struts 55 a-d increased shaped memory and facilitates more predictable bending of the struts into the desired expanded configuration of the electrode assembly. Following the heat setting, the tube 121 is cut adjacent the alignment members 123 to define the longitudinal end segments 59 of the struts 55 a-d for connecting the struts to the bushing 81 and subsequently to the catheter shaft 29 in the manner described previously. The tip 67 is secured to the distal end 53 of the electrode assembly 33 (e.g., to the connecting ring 61) in the manner described previously.
With reference back to FIGS. 3 and 4 as well as to FIG. 21, each of the struts 55 a-d of the illustrated electrode assembly 33 is suitably configured in at least the collapsed configuration of the electrode assembly to have what is referred to herein as a proximal leg 103 a-d, a distal leg 105 a-d, and a center segment 106 a-d extending between and interconnecting the proximal and distal legs of the strut. To facilitate predictable bending of the struts 55 a-d, each strut includes a pair of hinges 101 a-d, 102 a-d in longitudinally spaced relationship with each other, i.e., with one hinge 101 a-d intermediate and interconnecting the proximal leg 103 a-d and the center segment 106 a-d of the strut and the other hinge 102 a-d intermediate and interconnecting the distal leg 105 a-d and the center segment of the strut. In particular, with reference to the strut 55 a in FIG. 3, the proximal leg 103 a extends from the one hinge 101 a to the proximal end of the electrode assembly 33 and the distal leg 105 a extends from the other hinge 102 a to the connecting ring 61 at the distal end of the electrode assembly.
In the illustrated embodiment, the proximal leg 103 a-d and the distal leg 105 a-d of each strut 55 a-d are of generally equal length. In other embodiments, some of which are described later herein, the proximal leg 103 a-d and the distal leg 105 a-d may be of unequal length. Also, in the illustrated embodiment, each strut 55 a-d has a proximal leg 103 a-d, central segment 106 a-d and distal leg 105 a-d of lengths equal to the proximal leg, central segment and distal leg of each of the other struts so as to maintain symmetry of the electrode assembly 33. It is understood, though, that the respective lengths of the proximal leg 103 a-d, center segment 106 a-d and distal leg 105 a-d of one strut may be different from that of one or more of the other struts. The electrodes 57 are disposed respectively on the center segment 106 a-d of each corresponding strut 55 a-d.
In the illustrated embodiment of FIGS. 3 and 21, the proximal leg 103 a-d, the distal leg 105 a-d and the center segment 106 a-d each have a uniform width along the respective lengths thereof, i.e., other than where the proximal leg narrows to form the end segments 59 that connect to the bushing 81. However, it is contemplated that in other embodiments the proximal leg 103 a-d may have a non-uniform width, such as a width that decreases continuously (i.e., tapers or narrows) from adjacent the hinge 101 a-d to the end segment 59. Alternatively, or additionally, the distal legs 105 a-d may have a non-uniform width, such as a width that decreases continuously (i.e., tapers, or narrows) from adjacent the hinge 102 a-d to adjacent the connecting ring 61. In other embodiments, the width of each proximal leg 103 a-d and/or distal leg 105 a-d may be tapered in another suitable manner. The width of each center segment 106 a-d of each strut 55 a-d is generally uniform along its length. Each strut 55 a-d of the illustrated embodiment has a narrowed width intermediate the center segment 106 a-d and the proximal leg 103 a-d to define the hinge 101 a-d and another narrowed width intermediate the center segment and the distal leg 105 a-d to define the hinge 102 a-d. In the illustrated embodiment the width of each strut 55 a-d at the hinge 101 a-d is equal to the width of the strut at the other hinge 102 a-d. However, in other embodiments the width of the strut 55 a-d at the hinge 101 a-d may be different from the width of the strut at the other hinge 102 a-d and remain within the scope of this disclosure.
As used herein, the term “hinge” refers to any suitable intended, preset or predetermined point or zone of flexure or bending in the strut. For example, in the illustrated embodiment of FIG. 3, the hinges 101 a-d, 102 a-d are each formed by generally U-shaped symmetrical cut-outs on opposite sides of each strut 55 a-d so that the strut material is continuous across the narrowed width of the strut. The rounded contour of each of the cut-outs reduces the stress at the hinge 101 a-d, 102 a-d upon bending of the strut 55 a-d.
In other embodiments, such as illustrated in FIGS. 9-11, the hinges 101 a-d, 102 a-d (only one such hinge being illustrated) may be formed by symmetrical cut-outs that are other than generally U-shaped, such as generally V-shaped (FIG. 9), generally rectangular (FIG. 10), generally trapezoidal (FIG. 11) or other suitable shape. It is also understood that one or both of the hinges 101 a-d, 102 a-d may alternatively be formed by one or more interior openings 107 disposed between the side edges of the strut 55 a-d at the respective hinge so that the narrowed width of the strut at the hinge is defined by the combined widths of the transverse webs 108 of strut material remaining on both sides of such an opening. For example, as illustrated in the alternative embodiments of FIGS. 12 and 13, such an interior opening 107 may be circular, oval (FIG. 12), rectangular (FIG. 13) or other suitable shape. In the alternative embodiment of FIG. 14, the strut is widened at the hinge 101 a-d, 102 a-d to accommodate an interior opening 107 having a generally ovate shape. FIGS. 15 and 16 illustrate another alternative embodiment in which each hinge 101 a-d, 102 a-d comprises opposed, symmetrical cut-outs along with one or more interior openings 107. In particular, in FIG. 15 a pair of generally diamond-shaped interior openings 107 are formed in each strut 55 a-d adjacent the longitudinally opposite ends of the opposed cut-outs, while in FIG. 16 a single elongated interior opening 107 extends lengthwise from adjacent one end of the opposed cut-outs to adjacent the opposite end of the opposed cut-outs. It is contemplated that in other embodiments the opposed cut-outs may not be symmetrical.
FIGS. 17-20 illustrate additional alternative embodiments in which each hinge 101 a-d, 102 a-d is formed by two or more slots or cuts 109 extending transversely across the strut from opposite side edges of the strut. For example, in FIG. 17, a series of three generally V-shaped cuts 109 are formed in the side edges of the strut 55 a-d—i.e., with two of the V-shaped cuts extending from one side edge of the strut transversely across part of the strut and the other V-shaped cut extending from the opposite side of the strut transversely across part of the strut intermediate the other two V-shaped cuts. The cuts 109 may be other than V-shaped in other embodiments. FIGS. 18, 19 and 20 illustrate slots 111, each having a generally circular terminal end 113, extending transversely across part of the strut 55 a-d from opposite side edges thereof. For example, two such slots 111 are illustrated in FIG. 18, three such slots are illustrated in FIG. 19 and four such slots are illustrated in FIG. 20. It is understood that the number of slots 111 may be less than two or greater than four within the scope of this disclosure. It is also understood that the slots 111 may be shaped other than as illustrated and remain within the scope of this disclosure.
It is also contemplated that in other embodiments one or both of the hinges 101 a-d, 102 a-d of each strut 55 a-d may be formed other than by forming cut-outs or slots in the struts. For example, in some embodiments one or all of the struts 55 a-d may be of uniform width and cross-section along its entire length, but have a pair of longitudinally spaced preset bends or creases formed in the strut to respectively define the hinges 101 a-d, 102 a-d. In still other embodiments, a hinge 101 a-d, 102 a-d may be formed as a result of differing characteristics (e.g., transverse cross-section, thickness, width, etc.) between the proximal leg 103 a-d and the center segment 106 a-d and/or between the distal leg 105 a-d and the center segment.
With reference to FIG. 5, by facilitating bending of the struts 55 a-d at the respective hinges 101 a-d, 102 a-d in the expanded configuration of the electrode assembly 33, the center segment 106 a-d of each strut has only a slight arch as illustrated, and in some embodiments may be substantially flat along its length. As such, while the electrodes 57 are at different longitudinal positions along the length of the electrode assembly 33, the relatively little to no arch in each of the center segments 106 a-d of the struts 55 a-d facilitates concurrent apposition of all of the electrodes against the arterial wall while still accommodating a relatively compact configuration (due to the longitudinally different positions of the electrodes) in the collapsed configuration of the electrode assembly, and more particularly when the electrode assembly is further compressed transversely from the collapsed position for maneuvering of the catheter within the patient—such as within a guide tube or lumen.
In some embodiments, at least the center segments 106 a-d, the proximal and distal legs 103 a-d, 105 a-d and/or the hinges 101 a-d, 102 a-d are suitably configured to further facilitate the center segments 106 a-d of the struts 55 a-d having relatively little to no arch upon configuration of the electrode assembly 33 in its expanded configuration. For example, in one embodiment the center segments 106 a-d, and optionally the proximal and distal legs 103 a-d, 105 a-d may each have a width in the range of about 0.018 inches to about 0.038 inches. Additionally, or alternatively, the center segments 106 a-d, and optionally the proximal and distal legs 103 a-d, 105 a-d may each have a thickness in the range of about 0.003 inches to about 0.007 inches. It is understood, however, that the widths and/or thicknesses of the strut elements may be other than within the above ranges and remain within the present disclosure.
In addition to providing a relatively stiffened center segment, the hinges 101 a-d, 102 a-d may be relatively more flexible, such as by forming each hinge to have a width that is substantially less than the width of the center segments 106 a-d and the proximal and distal legs 103 a-d, 105 a-d, to facilitate bending at the hinges instead of along the center segment. For example, relative to the range of widths set forth above for the center segments 106 a-d and the proximal and distal legs 103 a-d, 105 a-d, the hinges 101 a-d, 102 a-d may each have a width in the range of about 0.008 inches to about 0.018 inches. It is understood, however, that the hinges 101 a-d, 102 a-d may have a greater width than as set forth above, including a width equal to the width of the center segments 106 a-d, such as where the hinges are formed by pre-bending and heat setting the struts 55 a-d at the desired hinge locations.
In other embodiments, at least the center segments 106 a-d of the struts and optionally the proximal and/or distal ends 103 a-d, 105 a-d may be configured, e.g., in transverse cross-section, to have an increased stiffness (i.e., resistance to flexing or bending) relative to a strut that is generally flat in transverse cross-section. For example, as illustrated best in FIG. 22, at least the center segment 106 a-d of each of the struts 55 a-d of the electrode assembly 33 of FIG. 3 is generally arcuate or cambered in transverse cross-section along the length of the center segment. More particularly, as seen in FIG. 3, each of the struts 55 a-d has a uniform arcuate transverse cross-section along its entire length, including the proximal and distal legs 103 a-d, 105 a-d of each strut.
However, it is understood that the center segment 106 a-d of each strut 55 a-d may be configured in transverse cross-section different from the proximal and distal legs 103 a-d, 105 a-d such that the center segment has a stiffness that is greater than the stiffness of each of the proximal leg and the distal leg. In such an embodiment (not shown), the difference in transverse cross-sectional configuration between the center segment 106 a-d and the proximal leg 103 a-d defines the one hinge 101 a-d while the difference in transverse cross-sectional configuration between the center segment and the distal leg 105 a-d defines the other hinge 102 a-d. It is understood that the proximal and distal legs 103 a-d, 105 a-d may have the same transverse cross-sectional configuration as each other, or they may have different transverse cross-sectional configurations, within the scope of this disclosure.
FIGS. 23-27 illustrate alternative transverse cross-section configurations of at least the center segment 106 a-d (and optionally the proximal leg 103 a-d and/or the distal leg 105 a-d) of each strut 55 a-d. For example, the transverse cross-section may be configured to be an almost closed circle (FIG. 23), semicircular (FIG. 24), circular (FIG. 25), generally C-shaped (FIG. 26), generally U-shaped (FIG. 27), generally V-shaped (FIG. 28), generally M-shaped or W-shaped (FIG. 29) or other suitable configuration.
In other embodiments, the electrode assembly 33 may further include a stiffening element secured to or otherwise abutting at least the central segment 106 a-d (and, optionally, the proximal leg 103 a-d and/or the distal leg 105 a-d) of each strut 55 a-d to increase the stiffness thereof relative to a strut that lacks such a stiffening element. For example, in the illustrated embodiment of FIG. 30, the stiffening element comprises a relatively rigid wire 115 that may extend longitudinally along all or part of the length of at least the central segment 106 a-d of each strut 55 a-d in abutting relationship with the inner surface of the strut. The wire 115 adds rigidity to the central segment 106 a-d of the strut 55 a-d to thereby increase its stiffness. In the alternative embodiment of FIG. 31, the stiffening element comprises a relatively rigid sheath 117 that circumferentially surrounds at least the central segment 106 a-d of each of the struts 55 a-d along all or part of the length of the central segment. While in the illustrated embodiment the sheath 117 extends about the full circumference of the central segment 106 a-d of each strut 55 a-d, it is contemplated that in other embodiments the sheath may extend circumferentially about only a portion of the circumference of the central segment. It is also understood that the stiffening element may be any suitable stiffening element other than the wire of FIG. 30 or the sheath of FIG. 31. It is further understood that the stiffening element may further extend along all or part of the proximal leg 103 a-d and/or the distal leg 105 a-d of each strut 55 a-d and remain within the scope of this disclosure.
With reference now to FIGS. 32 and 33, another embodiment of an electrode assembly 233 is illustrated as having a pair of struts 255 a, b instead of the four struts 55 a-d described in the previous embodiments. It is understood, however, that the electrode assembly 233 of this embodiment may have more than two struts 255 a, b. As in the previous embodiments, each of the struts 255 a, b of this embodiment has a proximal leg 303 a, b, a distal leg 305 a, b and a center segment 306 a, b extending longitudinally between and interconnecting the proximal and distal legs. The one strut 255 a has a hinge 301 a intermediate and interconnecting the proximal leg 303 a and the center segment 306 a, and another hinge 302 a intermediate and interconnecting the distal leg 305 a and the center segment. The other strut 255 b has a hinge 302 a intermediate and interconnecting the proximal leg 303 b and the center segment 306 b, and another hinge 302 b intermediate and interconnecting the distal leg 305 b and the center segment 306 b. The hinges 301 a, b, 302 a, b may be configured in accordance with any of the hinge configurations illustrated and described herein.
Additionally, a pair of electrodes 257 is disposed on the center segment 306 a, b of each of the struts 255 a, b of this embodiment. In other embodiments there may be a single electrode 257 on each of the struts 255 a, b, or there may be more than two electrodes on each of the struts. As best seen in FIG. 32, the electrodes 257 are disposed on the struts 255 a, b at different longitudinal positions (i.e., different longitudinal distances from the proximal end of the electrode assembly 233) so that in the collapsed configuration of the electrode assembly the electrodes on one strut are at different longitudinal positions than the electrodes on the other strut. This arrangement facilitates circumferentially compressing the electrode assembly 233 down to a smaller cross-section beyond that of the preset collapsed configuration of FIG. 32 to facilitate positioning of the electrode assembly in a guide tube or lumen.
In this embodiment, for each strut 255 a, b the length of the proximal leg 303 a, b is different from the length of the distal leg 305 a, b. For example, referring to the strut 255 a, the proximal leg 303 a thereof is shorter than the distal leg 305 a of the strut. Additionally, the length of the proximal leg 303 a of one strut 255 a is different from the length of the proximal leg 303 b of the other strut 255 b. In the illustrated embodiment, for example, the proximal leg 303 a of the one strut 255 a is shorter than the proximal leg 303 b of the other strut 255 b. Also in the illustrated embodiment, the corresponding distal legs 305 a, b of the struts 255 a, b are of different lengths. In particular, the distal leg 305 a of the one strut 255 a (having the shorter proximal leg 303 a) is longer than the distal leg 305 b of the other strut 255 b. Accordingly, the center segments 306 a, b of the struts 255 a, b are of a generally equal length. It is contemplated that in other embodiments the center segments 306 a, b of the struts 255 a, b may be of different lengths. In such embodiments the proximal legs 303 a, b of the struts 255 a, b may be of different lengths while the distal legs 305 a, b are of a generally equal length, or the distal legs may be of different lengths while the proximal legs are of a generally equal length.
With the struts 255 a, b configured in this manner, upon configuration of the electrode assembly 233 to its expanded configuration the center segments 306 a, b become longitudinally offset from each other as illustrated in FIG. 33 due to the different lengths of the respective proximal and distal legs 303 a, b, 305 a, b of the struts. The electrodes 257 on the struts 255 a, b, which are at different longitudinal positions in the collapsed configuration of the electrode assembly 233 (FIG. 32) suitably become positioned at substantially the same longitudinal position on each of the struts in the expanded configuration of the electrode assembly. In some ablation procedures it is advantageous to have the electrode(s) 257 on each strut 255 a, b at generally the same longitudinal position.
FIGS. 34 and 35 illustrate another embodiment of an electrode assembly 433 having a pair of struts 455 a, b. It is understood, however, that the electrode assembly 433 of this embodiment may have more than two struts 455 a, b. As in the previous embodiments, each of the struts 455 a, b of this embodiment has a proximal leg 503 a, b, a distal leg 505 a, b and a center segment 506 a, b extending longitudinally between and interconnecting the proximal and distal legs. Each strut 455 a, b also has a first hinge 501 a, b intermediate and interconnecting the proximal leg 503 a, b and the center segment 506 a, b, and a second hinge 502 a, b intermediate the distal leg 505 a, b and the center segment. The hinges 501 a, b, 502 a, b may be configured in accordance with any of the hinge configurations illustrated and described herein.
In this embodiment, the center segment 506 a, b of each strut 455 a, b is configured to be generally concave as it extends lengthwise between the proximal and distal legs 503 a, b, 505 a, b of the electrode assembly 433. The concave configuration of the center segment 506 a, b may be formed by including a hinge 507 a, b (having any of the configurations illustrated and described herein) intermediate the longitudinal ends of the center segment 506 a, b, or by arching, or bowing the center segment transversely inward and heat setting the center segment in such an arched or bowed configuration to define the collapsed configuration of the electrode assembly 433 as illustrated in FIG. 34.
Upon configuration of the electrode assembly 433 to its expanded configuration, as illustrated in FIG. 35, the proximal and distal legs 503 a, b, 505 a, b of each strut 455 a, b are urged generally longitudinally outward while the center segment 506 a, b is urged to un-bow to the extent that the center segment is less arched or bowed, or is more suitably only slightly arched or bowed, and is even more suitably generally straight, or flat in the expanded configuration of the electrode assembly. While in the illustrated embodiment the hinges 501 a, b, 502 a, b and 507 a, b are illustrated as being a relatively sharp bend, it is understood that in other embodiments one or more of the hinges may be formed as a more gradual or rounded configuration and remain with the scope of this disclosure. The corresponding electrodes 457 on each strut 455 a, b are suitably at different longitudinal positions, for reasons discussed previously herein, and in the illustrated embodiment they are each positioned on the respective center segment 506 a, b of the strut.
FIGS. 36, 37 and 38 each illustrate further alternative embodiments of an electrode assembly 633, each having a pair of struts 655 a, b. It is understood, however, that the electrode assemblies 633 of these embodiment may have more than two struts. Each of the struts 655 a, b has a riser element 673 intermediate the proximal and distal ends 651, 653 of the electrode assembly 633 to facilitate a greater transversely outward point of contact of the electrodes against the arterial wall upon configuring the electrode assembly in its expanded configuration. In the illustrated embodiment of FIG. 36, for example, each strut 655 a, b has a pair of riser elements 673—with each riser element comprising a generally trapezoidal configuration formed in the strut. Each riser element may be formed in the respective strut using one or more hinges 707 a, b. In this embodiment, one hinge 707 a, b is common to both of the riser elements 673 on each strut 655 a, b. It is understood, however, that the riser elements 673 on each strut 655 a, b may be discrete from each other, e.g., without sharing a common hinge 707 a, b. The hinges 707 a, b may each be configured in accordance with any of the hinge configurations described previously herein. Upon configuration of the electrode assembly 633 to its expanded configuration (not shown), the riser element 673 of each strut 655 a, b defines the transversely outermost extent of the respective strut. The electrodes 657 of the electrode assembly 633 are each disposed on a respective one of the riser elements 673 to facilitate apposition of the electrodes against the arterial wall.
In the embodiment illustrated in FIG. 37, the struts 655 a, b of the electrode assembly 633 each include a single riser element 673 comprised of a generally trapezoidal configuration formed in the strut. As in the previous embodiment, each riser element 673 is suitably formed in the respective strut 655 a, b using suitable hinges 707 a, b. In the embodiment of FIG. 38, each of the struts 655 a, b is generally arcuate in the collapsed configuration of the electrode assembly 633. Each of the riser elements 673 comprises a generally rounded bump formed and preset in the strut 655 a, b intermediate the proximal and distal ends of the electrode assembly 633. It is understood that the bump 673 may be larger or smaller than as illustrated in FIG. 38 without departing from the scope of this disclosure. It is also understood that the riser elements 673 may be formed in the struts 655 a, b of the electrode assembly 633 in any other suitable manner and/or configuration without departing from the scope of this disclosure.
Although certain embodiments of this disclosure have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this disclosure. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the disclosure. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the disclosure as defined in the appended claims.
When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above constructions without departing from the scope of the disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

What is claimed is:

1. An electrode assembly for an electrode catheter system, the electrode assembly having a longitudinal axis, a proximal end and a distal end, the electrode assembly comprising:

first and second struts each extending from the proximal end to the distal end of the electrode assembly and having a corresponding electrode disposed thereon intermediate said proximal and distal ends of the electrode assembly, wherein the electrode assembly is configurable between a collapsed configuration and an expanded configuration, the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration, in the collapsed configuration the electrode on the first strut being at a first longitudinal position intermediate the proximal and distal ends of the electrode assembly and the electrode on the second strut being at a second longitudinal position intermediate the proximal and distal ends of the electrode assembly and different from the first longitudinal position of the electrode on the first strut, in the expanded configuration the first longitudinal position of the electrode on the first strut being substantially equal to the second longitudinal position of the electrode on the second strut.

2. The electrode assembly of claim 1 wherein each of the first and second struts comprises a longitudinally extending proximal leg, a longitudinally extending distal leg, and a center segment extending between and interconnecting the proximal leg and the distal leg, the corresponding electrodes being disposed on the center segment of each respective one of the first and second struts, the proximal leg of the first strut having a first length and the proximal leg of the second strut having a second length different from the first length of the proximal leg of the first strut.

3. The electrode assembly of claim 2 wherein the center segment of the first strut has a first length and the center segment of the second strut has a second length substantially equal to the first length of the center segment of the first strut.

4. The electrode assembly of claim 2 wherein the distal leg of the first strut has a first length and the distal leg of the second strut has a second length different from the first length of the distal leg of the first strut.

5. The electrode assembly of claim 2 wherein each strut further comprises a first hinge interconnecting the proximal leg and the center segment, and a second hinge interconnecting the distal leg and the center segment.

6. An electrode assembly for an electrode catheter system, the electrode assembly having a longitudinal axis, a proximal end and a distal end, the electrode assembly comprising:

a plurality of struts each extending from the proximal end to the distal end of the electrode assembly, each strut comprising a longitudinally extending proximal leg, a longitudinally extending distal leg, and a center segment extending between and interconnecting the proximal leg and the distal leg, the proximal leg and the distal leg of at least one of the struts having a corresponding stiffness, the center segment of said at least one of the struts having a stiffness greater than the stiffness of each of the proximal leg and the distal leg of said at least one of the struts, the center segment of each of the struts having a corresponding electrode thereon, wherein the electrode assembly is configurable between a collapsed configuration and an expanded configuration, the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration.

7. The electrode assembly of claim 6 wherein each strut comprises a first hinge interconnecting the center segment with the proximal leg of said strut and a second hinge interconnecting the center segment with the distal leg of said strut.

8. The electrode assembly of claim 6 wherein the center segment of each strut has a cross-section configuration, at least one of the proximal end and the distal end of each strut having a cross-section configuration that is different from the cross-section configuration of the center segment.

9. The electrode assembly of claim 8 wherein the center segment of each strut has a cross-section configuration selected from the group comprising: cambered, semicircular, circular, almost closed semicircular, C-shaped, U-shaped, V-shaped, W-shaped and M-shaped.

10. The electrode assembly of claim 6 further comprising, for each strut, a respective stiffening element at least one of on and abutting at least the center segment of the strut to increase the stiffness thereof.

11. The electrode assembly of claim 7 wherein the strut is generally uniform in cross-section along its length, the first and second hinges being heat-set hinges in which each strut is pre-bent at each of the first and second hinges to define the collapsed configuration of the electrode assembly.

12. The electrode assembly of claim 6 wherein each electrode is disposed on a respective strut at a longitudinal distance from the proximal end of the electrode assembly, the longitudinal distance of one electrode being different from the longitudinal distance of at least one other electrode, in the expanded configuration of the electrode assembly the electrodes being transversely spaced from the longitudinal axis of the electrode assembly approximately the same distance.

13. An electrode assembly for an electrode catheter system, the electrode assembly having a longitudinal axis, a proximal end and a distal end, the electrode assembly comprising:

a plurality of struts each extending from the proximal end to the distal end of the electrode assembly, each strut comprising a longitudinally extending proximal leg, a longitudinally extending distal leg, and a center segment extending between and interconnecting the proximal leg and the distal leg, the center segment of each of the struts having a corresponding electrode thereon, wherein the electrode assembly is configurable between a collapsed configuration and an expanded configuration, the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration.

14. The electrode assembly of claim 13 wherein each strut comprises a first hinge interconnecting the center segment with the proximal leg of said strut and a second hinge interconnecting the center segment with the distal leg of said strut.

15. The electrode assembly of claim 13 wherein, for at least one of the struts, the center segment has a stiffness, the proximal leg has a stiffness different from the stiffness of the center segment and the distal leg has a stiffness different from the stiffness of the center segment, the first hinge being defined by the difference in stiffness between the center segment and the proximal leg and the second hinge being defined by the difference in stiffness between the center segment and the distal leg.

16. The electrode assembly of claim 15 wherein, for at least one of the struts, the center segment has a cross-section along its length, the proximal leg has a cross-section along its length and different from the cross-section of the center segment, and the distal leg has a cross-section along its length and different from the cross-section of the center segment, the first hinge being defined by the difference in cross-section between the center segment and proximal leg, the second hinge being defined by the difference in cross-section between the center segment and the distal leg.

17. The electrode assembly of claim 13 wherein the first hinge is formed by at least one cut-out formed in the strut between the center segment and the proximal leg and the second hinge is formed by at least one cut-out formed in the strut between the center segment and the distal leg.

18. The electrode assembly of claim 13 wherein the strut has opposed side edges, each of the first and second hinges being defined by at least two transversely extending slots formed in the opposed side edges, wherein for each of the first and second hinges at least one of the slots extends transversely from one of the side edges and terminates prior to the opposite side edge, and at least one other one of the slots extends transversely from the opposite side edge and terminates prior to said one of the side edges, the slots being longitudinally spaced from each other at the respective first and second hinges.

19. The electrode assembly of claim 13 wherein the proximal leg of at least one strut has a first length and the proximal leg of at least one other strut has a second length different from said first length

20. The electrode assembly of claim 13 wherein the center segment of the at least one strut has a first length and the center segment of the at least one other strut has a second length substantially equal to the first length of the center segment of the at least one strut.

21. An electrode assembly for an electrode catheter system, the electrode assembly having a longitudinal axis, a proximal end and a distal end, the electrode assembly comprising:

a plurality of struts each extending from the proximal end to the distal end of the electrode assembly, each strut having a riser element disposed thereon intermediate the proximal end and the distal end of the electrode assembly, the electrode assembly being configurable between a collapsed configuration and an expanded configuration, in the expanded configuration the riser element of each strut extending transversely outward from the longitudinal axis of the electrode assembly a greater distance than any other point along the respective strut, each strut further having an electrode disposed on the respective riser element.

22. The electrode assembly of claim 21 wherein each riser element is located a longitudinal distance from the proximal end of the electrode assembly, the riser element of one strut being at a longitudinal distance that is different from the longitudinal distance of the riser element of at least one other strut.

23. The electrode assembly of claim 21 wherein the electrode assembly has a length from its proximal end to its distal end, the length of the electrode assembly decreasing upon configuration of the electrode assembly from its collapsed configuration to its expanded configuration.

24. The electrode assembly of claim 21 wherein the struts are formed integrally with each other.

25. The electrode assembly of claim 21 in combination with the catheter system, the catheter system comprising a handle, an elongate shaft extending from the handle, the electrode assembly, and an actuator associated with the handle and operatively connected to the electrode assembly for selectively configuring the electrode assembly from its collapsed configuration to its expanded configuration.

26. An electrode assembly for an electrode catheter system, the electrode assembly having a longitudinal axis, a proximal end and a distal end, the electrode assembly comprising:

a plurality of struts each extending from the proximal end to the distal end of the electrode assembly and each having a corresponding electrode thereon, wherein the electrode assembly is configurable between a collapsed configuration and an expanded configuration, the electrodes being transversely spaced from the longitudinal axis of the electrode assembly a greater distance in the expanded configuration than in the collapsed configuration, in the collapsed configuration at least one of the struts having a generally concave segment extending lengthwise along the strut intermediate the proximal and distal ends of the electrode assembly.

27. The electrode assembly of claim 26 wherein in the expanded configuration said segment of the strut is less concave than in the collapsed configuration of the electrode assembly.

28. The electrode assembly of claim 26 wherein in the expanded configuration said segment of the strut is generally flat along its length.

29. The electrode assembly of claim 26 wherein said at least one of the struts comprises a proximal leg, a distal leg and a central segment extending between and interconnecting the proximal leg and the distal leg, the central segment being generally concave as it extends lengthwise intermediate the proximal and distal legs in the collapsed configuration of the electrode assembly.