Patent Publication Number: US-10328238-B2

Title: Catheter system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional application Ser. Nos. 61/777,236, 61/777,249, and 61/777,259 filed Mar. 12, 2013, the entire specifications of which are 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 catheter system having at least one selectively adjustable feature, and still more particularly to a catheter system having multiple control lines associated with multiple components of the system, at least one of which is selectively adjustable. 
     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&#39;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. Controls, or actuators may be provided on the handle for selectively adjusting one or more characteristics of the working components. 
     One particular example of the catheter system is an ablative catheter system in which the working component is a multi-electrode component carried at the distal end of the catheter. A control wire extends within the shaft of the catheter from the electrode component to the handle to operatively connect the electrode component to an actuator on the handle. Actuation of the actuator acts on the control wire to configure the electrode component into a desired configuration. For example, in one such ablative catheter system made by St. Jude Medical, Inc. under the trade name EnligHTN, the multi-electrode component is in the form of an electrode basket. Upon locating the electrode basket at a desired location within the patient, actuation of the actuator on the handle pulls on the control wire to reconfigure the electrode from a collapsed configuration to an expanded configuration in which the electrodes are in contact with a surface, such as an arterial wall. It is thus important to maintain proper tension in the control wire. In some catheter systems, there may be a need for two or more separate control wires, such as where there are two or more working components carried by the catheter. In such an arrangement, it is desirable that proper tension in each of the control wires be maintained, particularly when only one of the control wires is being acted upon. It is also desirable to maintain a secure connection of the catheter to the handle. It is further desirable for the physician to be able to readily actuate the actuator, and for the system to facilitate maintaining the actuator in a desired position corresponding to a desired configuration of a working component. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     In one embodiment, a catheter system generally comprises a handle and an elongate hollow shaft having a proximal end connected to the handle and a distal end remote from the handle. A working component is carried by the shaft and has at least one characteristic that is adjustable. An actuator is rotatably mounted on the handle for selectively adjusting at least one characteristic of the working component. A control line extends at least in part within the shaft. The control line operatively couples the actuator with the working component such that rotation of the actuator relative to the handle effects linear translation of the control line to adjust the at least one characteristic of the working component. 
     In one embodiment of a method of controlling a catheter system of the type having a handle and a working component operatively coupled to the handle by a control line, the method generally comprises rotating an actuator relative to the handle, and acting on the control line in response to rotation of the actuator to effect linear translation of the control line, the linear translation of the control line adjusting at least one characteristic of the working component. 
     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; 
         FIG. 2  is a side elevation of a catheter and handle of the catheter system of  FIG. 1 , with a distal or front end segment of a catheter shaft deflected relative to the remainder of the catheter shaft and with a slide actuator in its extended or actuated position corresponding to the deflection of the catheter shaft; 
         FIG. 3  is a side elevation similar to  FIG. 2 , but with the slide actuator in its neutral or unextend position corresponding to the catheter shaft being undeflected, and with an electrode basket of the catheter system in an expanded configuration resulting from rotation of a rotatable actuator; 
         FIG. 4  is a cross-section of a portion of the handle of the catheter system of  FIG. 1 ; 
         FIG. 5  is a cross-section of another portion of the handle of the catheter system of  FIG. 1 ; 
         FIG. 6  is an exploded view of the handle of the catheter system of  FIG. 1 ; 
         FIG. 7  is an enlarged portion of the cross-section of  FIG. 4 ; 
         FIG. 8  is a cross-section of the handle taken perpendicular to the cross-section of  FIG. 7 ; 
         FIG. 9  is a top plan view of an assembled worm gear housing, worm gear assembly and pinion member; 
         FIG. 9A  is a top plan view of the worm gear housing, 
         FIG. 10  is a bottom plan view of the assembled worm gear housing, worm gear assembly and pinion member; 
         FIG. 10A  is a bottom plan view of the worm gear housing; 
         FIG. 11  is a top plan view of a bottom half of the worm gear housing; 
         FIG. 12  is an exploded perspective view of a worm gear assembly of the handle of the catheter system of  FIG. 1 ; 
         FIG. 13  is a top plan view of a pinion member of the handle; 
         FIG. 14  is a front elevation of the pinion member of  FIG. 13 ; 
         FIG. 15  is a bottom plan view of a top half of a barrel housing of the handle; 
         FIG. 16  is a top plan view of a bottom half of the barrel housing of the handle; 
         FIG. 17  is a top plan view of the bottom half of the barrel housing with the bottom half of the worm gear housing, the worm gear assembly and the pinion member disposed therein; 
         FIG. 18  is a top plan view of a bottom half of the handle housing, with a bottom half of the barrel housing and the entire worm gear housing and related internal components disposed therein; 
         FIG. 19  is a top plan view of the bottom half of the handle housing, with the entire barrel housing, worm gear housing and related internal components disposed therein; 
         FIG. 20  is a top plan view of the bottom half of the handle housing, with the bottom half of the barrel housing, the bottom half of the worm gear housing, the worm gear assembly and the pinion member disposed therein, the pinion member being in an initial or neutral position corresponding to an undeflected configuration ( FIG. 1 ) of the catheter shaft; 
         FIG. 21  is a top plan view similar to  FIG. 20  with the pinion member pivoted relative to the handle housing to a maximum pivoted position corresponding to the maximum deflected configuration ( FIG. 2 ) of the catheter shaft; 
         FIG. 21A  is an enlarged cross-section of a portion of the handle of  FIG. 4 ; 
         FIG. 22  is a perspective view of a flex relief member of the handle of the catheter system of  FIG. 1 ; 
         FIG. 23  is a rear elevation thereof; 
         FIG. 24  is a perspective view of a shaft collar of the handle of the catheter system of  FIG. 1 ; 
         FIG. 25  is a cross-section thereof; 
         FIG. 26  is a cross-section thereof taken normal to the cross-section of  FIG. 22 ; 
         FIG. 27  is a perspective cross-section of the flex relief member and shaft collar with the catheter shaft connected thereto; 
         FIG. 28  is an exploded view of a handle of a second embodiment of a catheter system; and 
         FIG. 29  is a bottom plan view of a top half of a barrel housing of the handle of  FIG. 28 . 
     
    
    
     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 is indicated generally at  21  and includes a 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). 
     In the embodiments illustrated and described herein, the catheter system  21  includes an elongate flexible catheter  23  that is also selectively deflectable (e.g., bendable)—such as at or adjacent the end or tip, broadly referred to as a first working component or first component, of the catheter—as illustrated for example in  FIG. 2 . The catheter system  21  also includes what is broadly referred to as a second working component (or second component). As used herein, a working component is intended to refer to any component that is used for guiding, diagnostic, therapeutic, ablative or other function relating to a patient. Working components may be carried by the catheter  23  and selectively operated or adjusted. As used in herein, selective operation or adjustment of a working component is intended to refer to a functional changing of at least one characteristic of the working component, such as changing the configuration of the component, changing the orientation of the component, supplying current to the component, inflating or collapsing the component or otherwise adjusting, manipulating or operating the component for its intended purpose. 
     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 system is that 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 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 only the flexible catheter, 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). 
     The illustrated catheter  23  of  FIG. 1  includes an elongate, flexible hollow shaft  29  having a central passage and connected to the handle  25  at or near a proximal or rear end  31  (not visible in  FIGS. 1 and 2  but seen, e.g., in  FIG. 7 ) of the catheter shaft, and an electrode basket  33  (broadly, a working component and more broadly a second component of the catheter system) disposed at or near a distal or front end  35  (or what is sometimes referred to as the tip) of the catheter shaft. It is understood, however, that the electrode basket  33  may be disposed anywhere along the catheter shaft  29  intermediate the rear end  31  and the front 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. 
     The electrode basket  33  is suitably configurable between a collapsed configuration ( FIG. 1 ) and an expanded configuration ( FIG. 3 ). An annular (e.g., ring-shaped) actuator  37  ( FIG. 3 ) is mounted on the handle  25  for rotation relative thereto and is operatively connected to the electrode basket  33  for selectively configuring the electrode basket between its collapsed and expanded configurations. It is understood that other suitable actuators (e.g., slide, push button, lever, etc.) may be used instead of the rotating actuator  37  to selectively configure the electrode basket  33  without departing from the scope of this disclosure. In some embodiments, the electrode basket  33  may be selectively adjustable between an infinite number of configurations between its collapsed and expanded configurations using the actuator  37 . A control line, such as a suitable cable or pull wire  39  ( FIG. 4 ), extends from the electrode basket  33  within the hollow catheter shaft  29  and into the handle  25  and operatively connects the annular actuator  37  with the electrode basket via a worm gear assembly  306  ( FIG. 4  and described in further detail later herein) to which the pull wire is connected. While in the illustrated embodiment a single pull wire  39  is used to selectively configure the electrode basket, it is contemplated that two or more pull wires, cables or other suitable control lines may be used for selectively configuring the electrode basket. It is also understood that the control line may be any suitable control line other than a pull wire, such as a cable, string, tie, compression member or other suitable line useful to operatively connect the electrode basket  33  to the worm gear assembly  306  and hence the handle  25 . 
     In the illustrated embodiment, the catheter shaft  29  is also configured for deflection near the tip or front end  35  thereof, such as between an undeflected configuration ( FIG. 1 ) and a deflected (e.g., bent or angled) configuration ( FIG. 2 ) for use in guiding the catheter  23  into desired positions within the patient. As best seen in  FIGS. 1 and 2 , a suitable slide actuator  41  is mounted on the handle  25  for sliding movement longitudinally of the handle and is operatively connected to the deflectable segment of the catheter shaft  29  for movement between a first or neutral position ( FIG. 1 ) corresponding to the undeflected configuration of the catheter shaft and a second (e.g., extended) position ( FIG. 2 ) corresponding to the deflected configuration of the catheter shaft. The slide actuator  41  permits the catheter shaft  29  to be selectively deflected to any number of angular positions between the undeflected configuration and a predetermined maximum deflection (e.g., angular position) of the catheter. It is understood that any other suitable actuator (e.g., rotating, push button, lever, etc.) may be used to selectively adjust (e.g., deflect) the catheter shaft  29  without departing from the scope of this disclosure. 
     Another control line, such as a suitable cable or pull wire  43  ( FIG. 4 ), extends from the segment of the catheter shaft  29  that is deflectable (e.g., the front end  35  of the illustrated catheter shaft) within the hollow catheter shaft and into the handle  25  and operatively connects the slide actuator  41  with the deflectable segment of the catheter via a pinion member  401  ( FIG. 4  and described in further detail later herein) to which the pull wire is connected. While in the illustrated embodiment a single pull wire  43  is used to selectively deflect the catheter shaft  29 , it is contemplated that two or more wires, cables or other suitable control lines may be used for selectively bending the catheter. It is also understood that the control line  43  may be any suitable control line other than a pull wire, such as a cable, string, tie, compression member or other suitable line useful to operatively connect the deflectable segment of the catheter shaft  29  to the pinion member  401  and hence the handle  25 . The control line  43  associated with deflection of the catheter shaft  29  is different from the control line  39  associated with selectively configuring the electrode basket  33  to permit configuration of the electrode basket at least in part independent of the deflection of the catheter. 
     A conductive wire, or more particularly in the illustrated embodiment a twisted bundle  45  of two or more conductive wires ( FIG. 4 ) corresponding to the multiple electrodes of the electrode basket  33 , extends from the electrode basket within the catheter shaft  29  and into the handle  25  for electrical connection with the conductor assembly  27  to provide electrical communication between the power supply and the electrode basket. It is understood that the power supply may be any power supply, such as ultrasonic, RF or other suitable power supply. 
     With particular reference now to  FIGS. 4-6 , the handle  25  has a longitudinal or lengthwise axis X and generally comprises an outermost housing, referred to herein as a handle housing  101 , an intermediate housing, referred to herein as a barrel housing  201  extending longitudinally within the handle housing and being slidable longitudinally relative to the handle housing to broadly define an outer shuttle, and an innermost housing, referred to herein as a worm gear housing  301  extending longitudinally within the barrel housing and being slidable longitudinally relative to both the barrel housing and the handle housing to broadly define an inner shuttle. The illustrated handle housing  101  is of two piece construction (e.g., what is referred to herein as a top half  103  and a bottom half  105  of the handle housing). However, the handle housing  101  may be of any suitable alternative construction, such as of a single-piece construction or of more than two pieces. 
     The handle housing  101  has a proximal or rear end  107  ( FIG. 5 ) to which the conductor assembly  27  is connected in any suitable manner. In the illustrated embodiment of  FIG. 5 , for example, connection is by an inward tapered collar  109  at the rear end  107  of the handle housing  101  seating within an annular channel  65  formed in a connection plug  67  of the conductor assembly  27 . A retaining ring  68  seats over the tapered collar  109  to generally close the rear end  107  of the handle housing  101 . As seen in  FIGS. 4 and 6 , the handle housing  101  includes a pair of internal arcuate ribs  111  extending radially inward from the inner surface of the handle housing. These ribs  111  extend circumferentially about the inner surface of the handle housing  101  to longitudinally locate and retain a slide bearing  71  within the handle housing. 
     The handle housing  101  is configured adjacent its front end  113  as a cylindrical mount  115  for rotatably mounting the annular actuator  37  on the handle housing. A shoulder  117  ( FIGS. 4 and 18 ) is formed in the outer surface of the mount  115  to function as a stop to facilitate longitudinal positioning of the annular actuator  37  on the handle housing  101 . The shoulder  117  also accommodates a suitable sealing ring  119  (e.g., an elastomeric gasket or O-ring;  FIGS. 4 and 6 ) to seal the interface between the annular actuator  37  and the handle housing  101 . An opening  121  ( FIG. 6 ) is formed in the bottom half  105  of the handle housing  101  at the cylindrical mount  115  to facilitate operative connection of the annular actuator  37  with the electrode basket  33  via the worm gear assembly  306  as described in detail later herein. 
     An annular groove  123  is formed in the outer surface of the handle housing  101  to facilitate mounting a sleeve  83  on the front end  113  of the handle housing. The sleeve  83 , as illustrated in  FIGS. 4 and 6-8 , has a first set of internal projections  85  ( FIGS. 6 and 7 ) extending radially inward from the inner surface of the sleeve. These projections  85  seat within the annular groove  123  to mount the sleeve  83  on the handle housing  101 . A second set of internal projections  87  (one of which is illustrated in  FIG. 7  and the other in  FIG. 8 ) extends radially inward from the inner surface of the sleeve  83  in longitudinally spaced relationship with the first set of internal projections  85 , and more particularly nearer to a front end of the sleeve. With the sleeve  83  mounted on the handle housing  101 , the second set of internal projections  87  abuts against the front end  113  of the handle housing as illustrated in  FIGS. 4, 7 and 8  to secure the sleeve on the handle housing against longitudinal movement relative thereto. 
     Referring now to  FIGS. 9-12 , the illustrated worm gear housing  301  (broadly, the inner shuttle of the handle  25 ) is of two-piece construction, referenced herein as a top half  303  and a bottom half  305 . In other suitable embodiments the worm gear housing  301  may be of single-piece construction, or constructed of more than two pieces. The worm gear assembly  306  ( FIGS. 9 and 12 ) is positionable longitudinally within the worm gear housing  301  and includes a worm gear  307  rotatable on a linear bushing  309 . The linear bushing  309  has a head  311 , and a smaller diameter shaft  313  extending longitudinally forward from the head. A pair of locating pins  315  project from the outer circumference of the head  311  for seating in a longitudinally extending slot  317  (as illustrated best in  FIG. 9 ) in the top half  303  of the worm gear housing  301  to locate and retain the worm gear assembly  306  in the worm gear housing and to inhibit the head  311  of the worm gear bushing  309  against rotation relative to the worm gear housing. The slot  317  is sized in length to permit longitudinal translation of the worm gear assembly  306  relative to the worm gear housing  301  in response to rotation of the worm gear  307  on the bushing  309 . A distal or front end  319  of the bushing shaft  313  has an annular groove  321  formed therein to facilitate mounting of the worm gear  307  on the bushing  309 . 
     The illustrated worm gear  307  is generally tubular, having a central channel  323  for receiving the bushing shaft  313  therein. Catches (not shown) project radially inward of the channel  323  from the inner surface of the worm gear  307  for seating in the annular groove  321  of the bushing shaft  313  to mount the worm gear on the bushing for rotation on the shaft of the bushing. A lever arm  325  extends radially outward from the worm gear  307  for operative connection with the annular actuator  37 . In particular, the bottom half  305  of the worm gear housing  301  has a window  327  ( FIGS. 6, 10 and 11 ) through which the worm gear lever arm  325  extends when the worm gear assembly  306  is otherwise housed within the worm gear housing as illustrated in  FIG. 10 . A longitudinally extending groove  329  ( FIG. 6 ) is formed in the inner surface of the annular actuator  37  and is configured to receive the outer end of the worm gear lever arm  325  upon assembly of the handle  25  such that rotation of the annular actuator drives rotation of the worm gear  307  relative to the worm gear housing  301  (and hence the handle  25 ). 
     Suitable worm gear threads  331  project outward from the worm gear  301  (e.g., two sets of worm gear threads are illustrated in the various embodiments, such as in  FIG. 12 ) and seat within corresponding guide channels  333  (one of which is illustrated in  FIG. 11 ) formed in the respective inner surfaces of the top half  303  and bottom half  305  of the worm gear housing  301 . The worm gear threads  331  and corresponding guide channels  333  are configured such that upon rotation of the worm gear  307  relative to the worm gear housing  301  (e.g., due to rotation of the annular actuator  37  from an initial or neutral position corresponding to the collapsed configuration of the electrode basket  33  to a rotated position corresponding to the expanded configuration of the electrode basket), the worm gear assembly  306  moves linearly (i.e., longitudinally) rearward relative to the worm gear housing. 
     As best seen in  FIG. 4 , the shaft  313  of the linear bushing  309  is hollow. A threaded bore  335  extends transversely through the sidewall of the bushing head  311 , with a substantially smaller bore  337  being formed longitudinally in the head of the bushing so as to provide communication between the hollow shaft  313  of the bushing  309  and the threaded bore formed in the head of the bushing. In this manner, the pull wire  39  associated with the electrode basket  33  extends into the worm gear housing  301  and through the worm gear  307  and bushing shaft  313 . The pull wire  39  further extends through the smaller bore  337  in the head  311  of the bushing  309  into the threaded bore  335 . A suitable fastener or rotatable plug  339  is disposed in the threaded bore  335  and captures (e.g., coils) the pull wire  39  to operatively connect the electrode basket  33  with the worm gear assembly  306 , and hence the annular actuator  37  via the lever arm  325 . The plug  339  also facilitates predetermined tensioning of the pull wire  39 , e.g., upon assembly or subsequent adjustment of the handle. A notch  308  ( FIG. 10 ) is formed in the bottom half  305  of the worm gear housing  301  to provide access to the plug  339  even after assembly of the worm gear housing and barrel housing  201 . 
     In operation, rotation of the annular actuator  37  from its initial position to its rotated position causes the worm gear assembly  306  to translate longitudinally rearward relative to the worm gear housing  301 , thus further tensioning the pull wire  39  (i.e., broadly, acting on the control line) to effect expansion of the electrode basket  33  as illustrated in  FIG. 3 . Rotation of the annular actuator  37  in the opposite direction releases the additional tension in the pull wire  39  to thereby allow the electrode basket  33  to return to its collapsed configuration ( FIG. 1 ). 
     With general reference now to  FIGS. 4, 6 and 15-21 , the barrel housing  201  (broadly, the outer shuttle) is also of two-piece construction, including what is referred to herein as a top half  203  ( FIG. 15 ) and a bottom half  205  ( FIG. 16 ). In other suitable embodiments, the barrel housing  201  may be of single-piece construction, or constructed of more than two pieces. The top half  203  of the barrel housing  201 , as best illustrated in  FIG. 15 , includes a guide slot  207  for receiving a locating tab  341  ( FIGS. 6, 9 and 9A ) that projects radially outward from the outer surface of the top half  303  of the worm gear housing  301 . This guide slot  207  is sized in length to accommodate sliding movement of the locating tab  341 —and hence the worm gear housing  301 —relative to the barrel housing  201 . A second locating tab  209  ( FIG. 15 ) extends radially inward from the inner surface of the top half  203  of the barrel housing  201 —in longitudinally spaced relationship with the guide slot  207 —and is receivable in a corresponding slot  343  ( FIGS. 6 and 9 ) in the top half  303  of the worm gear housing  301 . A third locating tab (not shown) extends radially inward from the inner surface of the top half  103  of the handle housing  101  and is receivable in a corresponding slot  211  ( FIGS. 6 and 15 ) in the top half  203  of the barrel housing  201 . Locating the various tabs  341 ,  209  (the third tab, projecting from the handle housing  101 , not being shown) within the corresponding slots  207 ,  343 ,  211  in this manner also inhibits relative rotation of the respective housings  301 ,  201 ,  101  following assembly of the handle  25 . 
     The illustrated barrel housing  201  has a longitudinally proximal or rear end  213 , and a distal or front end  215 . As seen best in  FIGS. 17, 18 and 21A , a segment  217  of the barrel housing  201  adjacent its rear end  213  is sized in cross-section (e.g., in diameter in the illustrated embodiment) for slidable disposition within the slide bearing  71  to centrally position the barrel housing within the handle housing  101  while permitting sliding movement of the barrel housing (i.e., the outer shuttle) relative to the handle housing. An annular groove  219  is formed in the barrel housing segment  217  for seating an elastomeric sealing ring  221 , such as an O-ring or other suitable sealing ring. The sealing ring  221  outer diameter is sized for sliding contact of the sealing ring with the inner surface of the slide bearing  71  upon sliding movement of the barrel housing  201  relative to the handle housing  101 . 
     In a more particular embodiment, the elastomeric sealing ring  221  is generally loosely retained within the annular groove  219  of the barrel housing  201 . Upon assembly of the barrel housing  201  and sealing ring  221  into the handle housing  101  (and hence in the slide bearing  71 ), the radially outer surface of the sealing ring is compressed by the slide bearing to generate friction between the sealing ring and the slide bearing to facilitate retention of the barrel housing at generally any position along the possible longitudinal travel of the barrel housing relative to the handle housing. In one particularly suitable embodiment, the friction between the sealing ring  221  and slide bearing  71  is sufficient to retain the barrel housing  201  at a desired longitudinal position, but sufficiently loose enough to permit the operator of the catheter system  21  to move the barrel housing the slide actuator  41  (e.g., to deflect the catheter shaft  29 ) with one hand. 
     As one example, the elastomeric sealing ring  221  may be suitably constructed, and more suitably molded, of silicone. It is understood, though, that the sealing ring  221  may be constructed of another suitable elastomeric material or combination of materials without departing from the scope of this disclosure. The slide bearing  71  is suitably of single-piece molded plastic. For example, in one suitable embodiment the slide bearing  71  is constructed of an acetal material. In other embodiments, however, the slide bearing  71  may be made of other suitable materials or combination of materials. 
     As illustrated in  FIG. 21A , the inner surface (e.g., inner diameter) of the slide bearing  71  according to one embodiment is chamfered  51  at its longitudinal back end and defines a neutral or initial position of the barrel housing  201  (corresponding to the undeflected configuration of the catheter). The chamfer  51  provides compression relief of the sealing ring  221  in the neutral position of the barrel housing  201  to inhibit compression set over long periods of non-use of the catheter system  21 . The inner surface of the illustrated slide bearing  71  is also chamfered  53  at its longitudinal front end to provide a detent at the maximum longitudinal travel of the barrel housing  201  to thereby provide feedback to the operator that the barrel housing is at the maximum longitudinal travel thereof. 
     The bottom half  205  of the barrel housing  201  includes a window  223  ( FIGS. 6 and 16 ) formed therein to accommodate passage of the worm gear lever arm  325  therethrough (see, e.g.,  FIG. 17 ). The window  223  includes a notch  224  ( FIG. 16 ) that aligns with the notch  308  ( FIG. 10 ) of the bottom half  305  of the worm gear housing  301  to provide access to the plug  339  for adjusting the tension in the pull wire  39  even after assembly of the worm gear housing and barrel housing  201 . 
     The top half  203  and bottom half  205  of the barrel housing  201  also have respective, opposed pin seats  225  ( FIGS. 15 and 16 ) extending generally transversely inward from the respective inner surfaces thereof. These pin seats  225  are configured to pivotally retain the pinion member  401  ( FIG. 17 ) in the barrel housing  201  for longitudinal movement along with the barrel housing (i.e., the outer shuttle) relative to the handle housing  101 . 
     With particular reference to  FIGS. 13 and 14 , the pinion member  401  comprises a hub  403 , a primary (broadly, a first) pinion gear  405  disposed on one transverse side of the hub, and a pair of secondary pinion gears  407  (broadly, a second or at least one second pinion gear) disposed on a transverse side of the hub opposite the primary pinion gear. A pin  409  extends outward from each of the respective secondary pinion gears  407  as illustrated in  FIG. 14  to define a pivot or rotation axis Z of the pinion member  401 . Upon assembly of the handle  25 , the pins  409  seat within the respective pin seats  225  of the barrel housing  201  to pivotally secure the pinion member  401  in the barrel housing  201  while permitting pivoting movement of the pinion member relative to the barrel housing about the pivot axis Z. 
     As seen best in  FIG. 14 , the primary pinion gear  405  comprises two parallel rows of gear teeth  411 . It is understood that in alternative embodiments the primary pinion gear  405  may comprise a single row of gear teeth extending the width of the primary pinion gear, or a single row of gear teeth extending less than the entire width of the primary pinion gear. In other alternative embodiments, the primary pinion gear  405  may comprise more than two rows of gear teeth. A respective corresponding rack  127  (one of which is illustrated in  FIGS. 4 and 18-21 , the other of which is not shown but is identical to that illustrated in these Figures) extends inward from the inner surface of each of the top half  103  and bottom half  105  of the handle housing  101 . Accordingly, upon sliding movement of the barrel housing  201  (i.e., the outer shuttle) relative to the handle housing  101 , the interengagement of the primary pinion gear teeth  411  with the corresponding racks  127  on the handle housing  101  cause the pinion member  401  to pivot relative to the barrel housing  201  about the pivot axis Z of the pinion member from an initial or neutral position ( FIG. 20 ) toward a maximum pivoted position ( FIG. 21 ). 
     A central bore  413  ( FIG. 13 ) extends at least into, and in the illustrated embodiment it extends through (e.g., from the top to the bottom of), the hub  403  of the pinion member  401 . The bore  413  is threaded and receives a suitable fastener or rotatable plug  415  therein. A substantially smaller bore  417  extends transversely through the side of the pinion member hub  403  into open communication with the central bore  413 . As illustrated in  FIGS. 4 and 17 , the pull wire  43  associated with deflection of the catheter shaft  29  extends into the handle housing  101 , into the barrel housing  201  (and worm gear housing  301 ), and then through the smaller bore  417  in the hub  403  of the pinion member  401  into the central bore  413 . The plug  415  is used to coil the pull wire  43  to thereby selectively tension the pull wire to a predetermined desired tension. Accordingly, the catheter shaft  29  is operatively connected to the barrel housing  201  (i.e., the outer shuttle) via the pinion member  401 . 
     As illustrated in  FIGS. 9 and 10 , the pinion member  401  is disposed in part within the worm gear housing  301  upon assembly of the worm gear housing, with the pins  409  extending outward from windows  345  formed in the worm gear housing such that pins can seat in the respective pin seats  225  of the barrel housing  201 . An opening  346  ( FIGS. 10 and 10A ) in the bottom half  305  of the worm gear housing  301  and corresponding opening  226  ( FIG. 16 ) in the bottom half  205  of the barrel housing  201  provide access to the plug  415  (see, e.g.,  FIG. 10 ) to permit adjustment of the tension of the pull wire  43  even after assembly of the worm gear housing and barrel housing. 
     The central bore  413  of the pinion member  401  is offset from the pins  409  (and hence the pivot axis Z) such that upon pivoting movement of the pinion member about its pivot axis, the central bore  413  and plug  415  to which the pull wire  43  is connected orbits about the pivot axis of the pinion member. More particularly, in the initial or neutral position ( FIGS. 17-20 ) of the pinion member  401  corresponding to the undeflected configuration of the catheter shaft  29 , the primary pinion gear  405  and hence the central bore  413  and plug  415  of the pinion member are at a more longitudinally forward position relative to the barrel housing  201 . In particular, as illustrated best in  FIGS. 17 and 20 , to facilitate proper alignment of the pinion member  401  in its neutral position a post  318  extends within the worm gear housing  301  between the opposed top half  303  and bottom half  305  of the worm gear housing. In the neutral position of the pinion member  401 , the primary pinion gear  405  abuts against the post, with the rearwardmost teeth of the primary pinion gear intermeshed with the rearwardmost teeth of the rack  127  of the housing  101 . 
     Upon sliding movement of the barrel housing (i.e., the outer shuttle) in a forward direction relative to the handle housing  101 , the interengagement between the primary pinion gear teeth  411  and the racks  127  on the handle housing cause the pinion member to pivot about its pivot axis Z such that the primary pinion gear and hence the central bore  413  and plug  415  move in a generally rearward direction relative to the barrel housing  201  as illustrated in  FIG. 21 . Because the catheter shaft  29  (to which the pull wire  43  is connected) is being moved longitudinally forward along with the barrel housing  201  but the plug  415  (to which the pull wire  43  is also connected) is pivoted rearward relative to the barrel housing, tension in the pull wire  43  increases and thus causes the deflectable segment of the catheter shaft  29  to deflect towards its maximum deflected configuration. Rearward movement of the barrel housing  201  causes the pinion member  401  to pivot back toward its neutral position, thus releasing the additional tension in the pull wire  43  to allow configuration of the catheter shaft  29  back toward its undeflected configuration. 
     The front end  215  of the barrel housing  201  includes a pair of detents  227  ( FIG. 8 ) extending radially outward from the housing. The slide actuator  41 , as illustrated in  FIGS. 6-8 , has a central opening  55  sized for receiving the front end  215  of the barrel housing  201  therein. A pair of opposed guide channels  57  ( FIG. 8 ) extend longitudinally in the inner surface of the slide actuator  41  to accommodate the outward extending detents  227  of the barrel housing  201 . A pair of shoulders  59  ( FIG. 8 ) are formed on the inner surface of the slide actuator  41  adjacent the longitudinally front end thereof. 
     To operatively connect the slide actuator  41  to the barrel housing  201  (i.e., the outer shuttle), the slide actuator is placed on the front end  215  of the barrel housing, with the detents  227  of the barrel housing disposed in and sliding along the channels  57  in the inner surface of the slide actuator. Upon further placement of the slide actuator  41  onto the barrel housing  201 , the detents  227  become positioned just forward of the shoulders  59  formed in the inner surface of the slide actuator. The slide actuator  41  is then rotated relative to the barrel housing  201  so that the detents  227  seat on the shoulders  59  of the slide actuator to interlock and hence operatively connect the slide actuator to the barrel housing  201 . In this manner, sliding movement of the slide actuator  41  relative to the handle housing  101  as illustrated in  FIG. 2  operatively slides the barrel housing (i.e., the outer shuttle) therewith, and hence pivots the pinion member  401  relative to the barrel housing to selectively configure the catheter between its undeflected and deflected configurations. It is understood that an outer shuttle may be configured other than as a housing such as the barrel housing  201  without departing from the scope of this disclosure, as long as the pull wire  43  (i.e., the control wire) associated with deflection of the catheter is operatively coupled with the outer shuttle such that movement of the outer shuttle relative to the handle acts on the catheter shaft  29 , i.e., deflects the catheter shaft. 
     The catheter system  21  thus allows deflection of the catheter shaft  29  independent of selective configuration of the electrode basket  33  between its collapsed and expanded configurations using the annular actuator  37 . However, because the worm gear housing  301  and worm gear assembly  306  (to which the electrode basket pull wire  39  is connected) are disposed within and carried by the barrel housing  201 , the worm gear assembly and hence the connection point at which the electrode basket pull wire  39  is connected to the handle  25  move longitudinally forward relative to the handle housing  101  along with the barrel housing in response to actuation of the slide actuator  41 . As a result, regardless of whether the electrode basket  33  is in its collapsed configuration or its expanded configuration, the length of the pull wire  39  from the electrode basket to the connection point on the worm gear assembly  306  is relatively shortened in response to actuation of the slide actuator  41  to deflect the catheter shaft  29 . Accordingly, absent compensation for this shift, the pull wire  39  associated with the electrode basket  33  is susceptible to decreased tension and even the possibility of slack in the pull wire upon deflection of the catheter shaft  29 . To this end, according to one embodiment herein the pull wire  39  associated with the electrode basket  33  is responsive to adjustment of the catheter shaft  29  configuration to thereby inhibit slack from forming in the electrode basket pull wire. 
     More particularly, in the illustrated embodiment the worm gear housing  301 —disposed within the barrel housing  201  and together with the worm gear assembly defining an inner shuttle of the handle  25 —includes a rack  347  ( FIGS. 9, 9A, 10 and 10A ) formed along respective edges of the windows  345  formed in top half  303  and bottom half  305  of the worm gear housing  301 . As illustrated in  FIGS. 9 and 10 , the secondary pinion gears  407  interengage the respective racks  347  upon assembly of the worm gear housing  301  and barrel housing  201 . The secondary pinion gears  407  and the corresponding racks  347  on the worm gear housing  301  are configured and arranged such that upon pivoting of the pinion member  401  relative to the barrel housing  201 , the worm gear housing  301  and corresponding worm gear assembly  306  (i.e., the inner shuttle) are driven to move in a direction opposite the direction of movement of the barrel housing (i.e., longitudinally rearward in the illustrated embodiment). Stated another way, because the worm gear housing  301  and worm gear assembly  306  (i.e., the inner shuttle) are disposed within the barrel housing  201  and is thus moved longitudinally forward with the barrel housing relative to the handle housing  101  upon actuating the slide actuator  41  (and hence the barrel housing) forward, the secondary pinion gears  407  cause the worm gear housing  301  and assembly  306  to move longitudinally forward a distance less than the forward travel distance of the barrel housing. This is visible in  FIG. 21  by the gap  129  formed between the barrel housing  201  and the worm gear housing  301  when the barrel housing is moved to its maximum travel position corresponding to the deflected configuration of the catheter shaft  29 . 
     By reducing the longitudinally forward travel of the worm gear housing  301  and assembly  306  (i.e., the inner shuttle) relative to the forward travel of the barrel housing  201  (i.e., the outer shuttle), slack is inhibited from forming in the electrode basket pull wire. As such, the worm gear housing  301  and assembly  306  (i.e., the inner shuttle) along with the secondary pinion gears  407  together broadly define a compensator assembly to which the electrode basket pull wire  39  (i.e., the control line) is operatively coupled and is responsive to actuation of the slide actuator  41  (and hence deflection of the catheter shaft  29 ) to inhibit slack from forming in the electrode basket pull wire. However, the worm gear housing  301  and assembly  306  must move forward some distance along with the barrel housing  201  to avoid increasing tension in the electrode basket pull wire  39  to a tension that would unintentionally expand the electrode basket. It is understood that in other embodiments a suitable compensator assembly other than a shuttle and pinion gear arrangement may be used to inhibit slack from forming in the electrode basket pull wire (i.e., the control line), as long as the compensator is responsive to actuation of the slide actuator  41  (i.e., deflection of the catheter shaft  29 ) to inhibit slack from forming in the electrode basket pull wire. 
     In one embodiment, the difference between the barrel housing  201  travel and the worm gear housing  301  travel is at least in part a function of the gear ratio between the primary pinion gear  405  and the secondary pinion gears  407 , e.g., in view of the respective distances of the gears from the pivot axis Z of the pinion member  401 . For example, in the illustrated embodiment the primary pinion gear  405  is suitably spaced from the pivot axis Z a distance greater than the distance of the secondary pinion gears  407  from the pivot axis. It is understood, however, that the gear ratio may be other than as described above without departing from the scope of this disclosure, as long as it is sufficient to inhibit slack from forming in the electrode basket pull wire  39 . 
     With reference now to  FIGS. 7, 8 and 22-27 , in one embodiment, the catheter  23  and more particularly the catheter shaft  29  is suitably connected to the handle  25  by a collar  131  (broadly a connector) and flex relief member  133 . It is understood, however, that the flex relief member  133  may be omitted without departing from the scope of this disclosure. As illustrated in  FIGS. 24-27 , the collar  131  is generally tubular, having a frustoconical outer surface  135  tapering inward in cross-section from a longitudinally rear end  137  to a front end  139  thereof, and a central channel  141  extending the length of the collar and defining an inner surface of the collar. The central channel  141  includes a first segment  143  extending longitudinally from the front end  139  of the collar  131  and having a relatively greater transverse cross-section (i.e., diameter) to define a chamber for receiving the catheter shaft  29  into the collar, and a second segment  145  extending longitudinally from the rear end  137  of the collar and having a substantially smaller transverse cross-section than the first segment of the channel. A shoulder  147  is formed within the channel  141  by the reduced cross-section from the first to the second channel segments  143 ,  145  to thereby define a seat against which one end (i.e., the rear end) of the catheter shaft  29  abuts upon insertion of the catheter shaft into the collar  33  as illustrated best in  FIGS. 7, 8 and 27 . 
     In the illustrated embodiment, the first segment  143  of the channel  141  within collar  131  increases gradually (i.e., tapers outward) in transverse cross-sectional dimension (e.g., diameter) from the seat  147  to the front end  139  of the collar. More particularly, the diameter of the channel  141  at the seat  147  against which the shaft  29  abuts is substantially sized relative to the outer diameter of the catheter shaft to facilitate a close contact of the catheter shaft against the inner surface of the collar when the shaft abuts against the seat within the channel. Gradually increasing the transverse cross-sectional dimension of the channel  141  as it extends toward the front end  139  of the collar  131  provides a small clearance between the catheter shaft and the inner surface of the collar along a segment of the collar channel. 
     A port  149  is formed in and extends transversely through the sidewall of the collar  131  intermediate the front and rear ends  139 ,  137  of the collar, and more particularly at location along the channel segment where this is a small clearance between the inner surface of the collar and the outer surface of the catheter shaft. Upon assembly of the catheter shaft  29  with the collar  131 , the catheter shaft is inserted longitudinally inward into the collar channel  141  at the front end  139  of the collar until the end of the catheter shaft abuts against the seat  147  formed within the channel. A suitable adhesive, such as a UV adhesive, is injected through the fill port  149  into the channel  141 . The adhesive flows at least circumferentially around the outer surface of the catheter shaft  29  and in some embodiments also longitudinally within the segment of the channel  141  to fill the spacing between the catheter shaft outer surface and the relatively wider portion of the channel near the front end  139  of the collar (as well as some portions of the channel rearward of the fill port) to provide a circumferential bond between the collar and the catheter shaft. A uniform fill is controlled by the adhesive dispensing time. The collar  131  is suitably constructed of a material that permits the throughpassage of UV energy, such as a polycarbonate or other suitable material, to facilitate curing of the UV adhesive within the collar. 
     An annular flange  151  circumscribes the outer surface  135  of the collar  131  longitudinally inward from the rear end  137  of the collar, and more particularly at a location corresponding generally to the seat  147  formed within the collar channel  141 . The flange  151  provides a stop for limiting longitudinal insertion of the collar  131  into the flex relief member  133  as best illustrated in  FIGS. 7, 8 and 27 . A pair of longitudinally extending flanges  153  (each broadly defining a projection) extend on the outer surface  135  of the collar  131  from the annular flange  151  to the front end  139  of the collar on opposite sides of the collar. These longitudinally extending flanges  153  are received in corresponding grooves  161  ( FIGS. 22 and 23 ) of the flex relief member  133  as described in further detail below upon insertion of the collar  131  into the flex relief member to inhibit rotation of the collar (i.e., to provide torque resistance) relative to the flex relief member. 
     It is understood that a projection extending outward from the outer surface  135  of the collar  131  may be configured other than as a longitudinally extending flange  153 , such as in the form of a post or other suitable projection. It is also contemplated that a single projection, or more than two projections, may be used within the scope of this disclosure. It is also understood that the catheter shaft  29  may be connected to the handle  25  in another suitable manner without departing from the scope of this disclosure. 
     With reference to  FIGS. 22, 23 and 27 , the flex relief member  133  is generally tubular, having a central channel  163  extending the length of the flex relief member, e.g., from an open front end  165  to an open rear end  167  of the flex relief member. The central channel  163  of the illustrated flex relief member  133  comprises three particular segments. A collar housing segment  169  of the channel  163  extends longitudinally forward from the rear end  167  of the flex relief member  133 , and is configured in accordance with the outer surface of the collar  131  so as to receive the collar into the collar housing segment in a generally close fitting relationship with the flex relief member (see, e.g.,  FIG. 27 ). A seat  171  is formed generally at the rear end  167  of the flex relief member  133  to accommodate the annular flange  151  of the collar  131  to thereby facilitate proper longitudinal insertion of the collar into the flex relief member. 
     A grip segment  173  of the flex relief member channel  163  extends inward from the open front end  165  of the flex relief member  133  and is sized in transverse cross-section (e.g., diameter) for a close contact fit with the catheter shaft  29  within the flex relief member. In this manner, the catheter shaft  29  is inhibited against flexing at or near the collar  131  so as to inhibit the catheter shaft from being inadvertently disconnected or pulled out from the collar. An intermediate segment  175  of the flex relief member channel  163  extends longitudinally between the grip segment  173  and the collar housing segment  169  and is sized in transverse cross-section relatively larger than the cross-section of the catheter shaft  29 . However, it is contemplated that the intermediate segment  175  could be sized for a closer fit of the catheter shaft  29  with the flex relief member  133  along this segment of the channel  163 . 
     A mounting portion  177  of the flex relief member  133  is configured adjacent the rear end  167  thereof for being clamped by the barrel housing  201  of the handle  25  to retain the flex relief member on the handle. The illustrated mounting portion  177  includes a pair of generally square rib elements  179  disposed on opposite sides of the flex relief member  133 . Corresponding pockets  229  ( FIGS. 15 and 16 ) are disposed in the barrel housing  201  adjacent the front end  215  thereof for receiving the square rib elements  179  of the flex relief member  133 . This facilitates alignment of the flex relief member  133  in the barrel housing  201  and inhibits rotation of the flex relief member relative to the barrel housing following assembly of the handle  25 . An annular groove  181  is formed in the outer surface of the flex relief member  133  at the front end of the mounting portion  177  to receive a transversely inward extending flange  231  disposed at the front end  215  of the barrel housing  201  as illustrated best in  FIGS. 7 and 8  to thereby positively retain the flex relief member on the barrel housing. 
     A generally frustoconical closure member  183  circumscribes the flex relief member  133  forward of the mounting portion  177  and is sized in transverse cross-section to seat within the front end of the slide actuator  41  to generally close the front end of the handle  25  upon assembly of the handle to thereby inhibit dirt or other debris from getting into the handle. 
       FIGS. 28 and 29  illustrate a second embodiment of a catheter system  1021  generally similar to the catheter system  21  with the electrode basket (not shown but similar to the electrode basket  33  of the embodiment of  FIGS. 1-17 ) being configurable between its collapsed and expanded configurations upon rotation of an annular (e.g., ring-shaped) actuator  1037  relative to a handle  1025  of the catheter system. In this embodiment, however, the catheter shaft (not shown but similar to the catheter shaft  29  of the embodiment of  FIGS. 1-27 ) is retained against deflection near the front end of the catheter shaft. 
     In this embodiment, the top half  1203  of the barrel housing  1201  includes a guide slot  1207  for receiving a locating tab  1341  ( FIG. 28 ) that projects radially outward from the outer surface of the top half  1303  of the worm gear housing  1301 . This guide slot  1207  is sized in length to accommodate sliding movement of the locating tab  1341 —and hence the worm gear housing  1301 —relative to the barrel housing  1201 . A second locating tab (not shown but similar to the locating tab  209  illustrated in  FIG. 15 ) extends radially inward from the inner surface of the top half  1203  of the barrel housing  1201 —in longitudinally spaced relationship with the guide slot  1207 —and is receivable in a corresponding slot  1343  ( FIG. 28 ) in the top half  1303  of the worm gear housing  1301 . A third locating tab (not shown) extends radially inward from the inner surface of the top half  1103  of the handle housing  1101  and is receivable in a corresponding slot  1211  ( FIGS. 28 and 29 ) in the top half  1203  of the barrel housing  1201 . Locating the various tabs within the corresponding slots in this manner inhibits relative rotation of the respective housings following assembly of the handle  1025 . 
     As best illustrated in  FIG. 29 , in this embodiment the slot  1211  that receives the third locating tab (not shown) extending radially inward from the top half  1103  of the handle housing  1101  is substantially shorter in length than the slot  211  of the embodiment of  FIGS. 6 and 15 . The shortened slot  1211  inhibits the barrel housing  1201  against sliding movement relative to the handle housing  1101  so that no angular deflection of the front end of the catheter shaft can occur. As a result, the pull wire  43  of the embodiment of  FIGS. 1-27  that controls deflection of the front end of the catheter shaft is omitted from this embodiment. The pinion gear  401  of the embodiment of  FIGS. 1-27  is also omitted from this embodiment. 
     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&#39;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.