Patent Publication Number: US-2015073342-A1

Title: Linearly Stationary Catheter Drive Assemblies For Remote Catheter Positioning Systems

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present invention claims the benefit of priority to U.S. Provisional Patent Application No. 61/874,446, entitled “LINEARLY STATIONARY CATHETER DRIVE ASSEMBLIES FOR REMOTE CATHETER POSITIONING SYSTEMS,” filed Sep. 6, 2013, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Many procedures involving catheter insertion, such as invasive electrophysiology procedures, rely on fluoroscopy or other radioactive imaging techniques to help navigate and position the catheter within a patient&#39;s body at a particular site, such as in the heart or inside a blood vessel in the circulatory system. High dosages of radiation can have long term adverse health effects. A patient may be directly exposed only once or twice to radiation during such procedures and avoid such adverse effects. However, physicians, medical technicians and staff can experience a large cumulative radiation dosage over time, both directly and indirectly, from conducting many procedures. 
     To protect the operator and staff from this radiation, shielding such as lead aprons, gowns, glasses, skirts, etc., is worn. Such lead clothing, especially a lead apron, is quite heavy and uncomfortable, and its use has been associated with cervical and lumbar spine injury. 
     SUMMARY OF THE INVENTION 
     Systems, methods, and devices of the various embodiments provide linearly stationary catheter drive assemblies enabled to move a catheter&#39;s sheath along a linear axis while holding the catheter handle stationary along that linear axis. In the various embodiments, the linearly stationary catheter drive assembly may be configured to move the catheter&#39;s sheath along the linear axis while holding the catheter handle stationary along the linear axis and rotating the catheter handle about the linear axis. In an embodiment, a linearly stationary catheter drive assembly may include a loop drive configured to move the catheter sheath along the linear axis. In an embodiment, a linearly stationary catheter drive assembly may include a pinch drive configured to move the catheter sheath along the linear axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the features of the invention. 
         FIG. 1  and  FIG. 2  are perspective views of a catheter drive assembly including a loop drive suitable for use in one or more embodiments. 
         FIG. 3A  is a component diagram illustrating a catheter drive assembly as illustrated in  FIG. 1  and  FIG. 2  in one or more embodiments. 
         FIG. 3B  is a component diagram illustrating a catheter drive assembly as illustrated in  FIG. 1  and  FIG. 2  in one or more additional or alternative embodiments. 
         FIGS. 4A-4C  are diagrams illustrating relationships between rotational movement of an example loop drive and linear movement of a catheter sheath in one or more embodiments. 
         FIG. 5  is a perspective view of a pinch drive in one or more embodiments. 
         FIG. 6  is a cutaway perspective view of a pinch drive as illustrated in  FIG. 5 , in or more embodiments. 
         FIG. 7  is an exploded perspective view of a pinch drive as illustrated in  FIG. 5  in one or more additional or alternative embodiments. 
         FIGS. 8A-8C  are diagrams illustrating relationships between rotational movement of rollers of an example pinch drive and linear movement of a catheter sheath in one or more embodiments. 
         FIG. 9  is a perspective view of a catheter drive assembly including a pinch drive in one or more embodiments. 
         FIG. 10  is a system diagram illustrating an embodiment catheter positioning system. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes and are not intended to limit the scope of the invention or the claims. 
     Systems, methods, and devices of the various embodiments provide linearly stationary catheter drive assemblies enabled to move a catheter&#39;s sheath along a linear axis while holding the catheter handle stationary along that linear axis. In the various embodiments, the linearly stationary catheter drive assembly may be configured to move the catheter&#39;s sheath along the linear axis while holding the catheter handle stationary along the linear axis and rotating the catheter handle about the linear axis. Catheter drive assemblies according to the various embodiments may include a catheter driver and a catheter support coupled to the catheter driver. The catheter support may be configured to hold a handle of a catheter and the catheter driver may be configured to move a sheath of the catheter along a linear axis while the catheter support and the catheter handle remain stationary along the linear axis. In this manner, the catheter drive assemblies of the various embodiments may be linearly stationary in that the catheter drive assemblies of the various embodiments may enable a catheter sheath to be extended or retracted along the linear axis while the catheter support and the catheter handle do not move back or forth along that linear axis. 
     The linearly stationary catheter drive assemblies of the various embodiments may reduce the overall footprint of catheter positioning systems employing the embodiment linearly stationary catheter drive assemblies when compared with catheter positioning systems configured to move the catheter handle in a linear direction (e.g., track transiting catheter positioning systems) because the linearly stationary catheter drive assemblies may not require extensions approximately equal to the length of the catheter sheath in the linear direction along which to move the catheter handle. Additionally, the various embodiment linearly stationary catheter drive assemblies may accommodate catheters with longer sheaths without requiring modification (e.g., adding track length or additional sheath supports) to the linearly stationary catheter drive assemblies. In the various embodiments, the catheter contacting surfaces on the linearly stationary catheter drive assemblies may be sterile components, either sterilizable or disposable, to avoid introducing contaminants into the body of a patient. 
     In an embodiment, the catheter driver of a linearly stationary catheter drive assembly may be a loop drive configured to move the catheter sheath along the linear axis. In an embodiment, the loop drive may include a sheath guide wheel encircling the catheter support and configured to hold the shaft of the catheter around the outer edge of the sheath guide wheel. A guide wheel motor may rotate the shaft guide wheel, catheter support, and catheter handle together about an axis of rotation other than the linear axis, thereby extending or retracting the catheter shaft along the linear axis. In an embodiment, the guide wheel, catheter support, and catheter handle may be supported by a support frame which may be rotated by a frame motor, thereby rotating the support frame the guide wheel, catheter support, and catheter handle about the linear axis. In this manner, the catheter handle may rotate about the linear axis while not moving forward or backward along the linear axis. In an embodiment, the guide wheel motor may be supported by the support frame. In another embodiment, the guide wheel motor may be located in a portion of the catheter drive assembly not supported by the support frame. 
     In an embodiment, the catheter driver of a linearly stationary catheter drive assembly may be a pinch drive configured to move the catheter sheath along the linear axis. In an embodiment, the pinch drive may include a pair of rollers configured to be rotated by a roller motor in opposite directions to move the shaft of the catheter along the linear axis. In an embodiment, the pinch drive, catheter support, and catheter handle may be supported by a support frame. The pinch drive and catheter support may be rotationally coupled to the support frame, and a frame motor may rotate the pinch drive, catheter support, and catheter handle about the linear axis. In this manner, the catheter handle may rotate about the linear axis, approximately about the linear axis, or about a longitudinal axis of the catheter handle itself, which may or may not be in complete or precise alignment with the linear axis, while not moving forward or backward along the linear axis. 
     In an embodiment, a catheter positioning system may comprise a linearly stationary catheter drive assembly comprising a catheter driver and a catheter support configured to hold a handle of a catheter, a remote controller, and a processor connected to the remote controller and one or more motor of the catheter driver, the processor configured with processor-executable instructions to perform operations to activate one or more motors of the catheter driver to control in response to an input from the remote controller. In an embodiment, the catheter driver may be a loop drive. In another embodiment, the catheter driver may be a pinch drive. 
     Any type of catheter may be suitable for use with the various embodiments. Example catheters that may be used in various embodiments may include a handle portion and tube portion. The handle portion may be located at a proximal end of the catheters while the distal end of the tube portion may be inserted into the body of a patient. The handle portion of example catheters may also include an irrigation port, which may be used to introduce water or other fluids to lubricate the catheters and ease insertion or retraction into the patient. The handle portion may also include a back port through which one or more wires or cables may leave the handle portion. The one or more wires or cables may supply power to the example catheters or transmit signals, such as sending commands from a remote controller or other control device to the catheters or relaying data from one or more transducers present on the example catheters. Example catheters may include controls (e.g., on the handle portion) that control the behavior of the catheters. An example control that may be included on a catheter include a front flange and rear flange that may be squeezed together such that this motion may move one or more mechanism at the tip of the catheter (e.g., extending or retracting a laser tip from inside a tube portion of the catheter). The laser tip may be retracted by pulling the front flange and rear flange apart. Other example controls that may be include on a catheter include controls for deflecting the tip of the catheter to ease navigation inside a patient and/or for controlling one or more transducers at the tip (e.g., electrical leads, one or more sensor devices, ultrasound devices, etc.). The various embodiments may be applicable to catheters with different types of controls. The various embodiments may be applicable to catheters with different types of controls. The various embodiments may be especially applicable to flexible catheters, such as angioplasty catheters, but any type of catheter may be suitable for use with the various embodiments. 
       FIG. 1  and  FIG. 2  illustrate a catheter drive assembly  100  including a loop drive according to one or more embodiments.  FIG. 1  illustrates the sheath guide wheel  108 , catheter support  104 , and catheter handle  102   a  in a first position and  FIG. 2  illustrates the sheath guide wheel  108 , catheter support  104 , and catheter handle  102   a  moved to a second position as discussed further below. The sheath guide wheel  108  may be a rotational component that translates a rotational movement of the catheter sheath to a linear movement of the catheter sheath. In some embodiments, the sheath guide wheel  108  may be sterile when in use, because it comes into contact with the catheter sheath. The guide wheel  108  may be removable so that after use it may be removed for disposal (i.e., the sheath guide wheel may be a single use component) or for sterilization prior to the next use. 
     Referring to  FIG. 1 , the catheter drive assembly  100  may be coupled to a base  118  including various articulating joints  118   b,    118   d,    118   f,  and arms  118   a,    118   c,  and  118   e.  The base  118  may be coupled to a drive box  114  of the catheter drive assembly  100 , such as through the arms  118   a,    118   c,  and  118   e.  In an embodiment, connections for power, data, etc., to/from the catheter drive assembly  100  (e.g., motor control signals, motor power, catheter data connections, etc.) may pass through the base  118  to the drive box  114 . In various embodiments, one or more of the arms  118   a,    118   c,  and  118   e  may be rotated and one or more of the articulating joints  118   b,    118   d,  and  118   f  may be positioned so as to affect the position or orientation of the catheter drive assembly  100 . In an embodiment, the arm  118   a  of the base  118  may be rotationally coupled to the drive box  114  such that the angle of the catheter drive assembly  100  may be rotated about a longitudinal axis of the arm  118   a.  Other rotational movements of the arm portions of the base  118  (e.g., arms  118   c,    118   e ) may also be possible, which may be capable of positioning the catheter drive assembly  100  in embodiments. The drive box  114  of the catheter drive assembly  100  may be rotationally coupled to a support frame  106  which may support a loop drive that includes the sheath guide wheel  108  and a guide wheel motor. The support frame  106  may extend along the linear axis C. The drive box  114  may include a frame motor configured to rotate the support frame  106  about the linear axis C clockwise or counterclockwise, such as in the B′ directions. 
     The catheter support  104  may be coupled to the sheath guide wheel  108  of the loop drive, and the sheath guide wheel  108  may encircle the catheter support  104 . The support frame  106  may include a rotator housing  106   a  that may be coupled to and support the catheter support  104 . The support frame  106  may be coupled to and support the catheter support  104 , such as in a rotation plane above the support frame  106  through a rotating shaft extending from the center of the rotator housing  106   a  and coupling to the catheter support  104  at or near the axis of rotation A. In this manner, rotation of the rotating shaft in the rotator housing  106   a  may rotate the catheter support  104 , the sheath guide wheel  108  coupled to it, and the catheter handle  102   a  together clockwise or counterclockwise in the A′ direction about the axis of rotation A. 
     The catheter support  104  may be configured to hold the catheter handle  102   a  of the catheter  102  and the catheter sheath  102   c  of the catheter  102  may extend through an opening in the sheath guide wheel  108  and loop around an outer edge, channel, groove, or other catheter sheath retaining surface of the sheath guide wheel  108 . While the various examples are illustrated with the catheter sheath  102   c  looping around the sheath guide wheel  108  clockwise in the A′ direction, the catheter sheath  102   c  may loop around the sheath guide wheel  108  clockwise or counterclockwise in the A′ direction depending on how an operator of the catheter drive assembly  100  may thread the catheter sheath  102   c  through the opening in the sheath guide wheel  108  and around the outer edge of the sheath guide wheel  108 . In an embodiment, a back end of the catheter handle  102   a  of the catheter  102  may include a wired or wireless connector port  102   b  for connecting the catheter  102  to a processor of a catheter positioning system. In an embodiment, the sheath guide wheel  108  may include a grove along the outer edge to hold the catheter sheath  102   c.  The catheter sheath  102   c  may only partially encircle the outer edge of the sheath guide wheel  108  depending on the length of the catheter sheath  102   c  and an amount of sheath  102  extended or retracted in the C′ direction along the linear axis C. In some embodiments, the catheter sheath  102   c  may overlay itself in multiple turns around the sheath guide wheel  108 , particularly when the sheath is significantly retracted. 
     The support frame  106  may include an introducer  106   b  configured to guide the catheter sheath  102   c  of the catheter  102  for insertion into a body of a patient. The support frame  106  may include a first roller  110   a  and second roller  110   b.  The first roller  110   a  and the second roller  110   b  may be configured such that the catheter sheath  102   c  bends around and moves freely across the first rollers  110   a  and the second roller  110   b  as the catheter sheath  102   c  is fed from the outer edge of the sheath guide wheel  108  to the introducer  106   b.  The circumference of the first roller  110   a  and second roller  110   b  may selected such that the bend in the catheter sheath  102   c  may not be too sharp as to cause damage to the catheter sheath  102   c  when being bent toward the introducer  106   b  and into the C′ direction along the linear axis C. Additionally, the circumference of the sheath guide wheel  108  may be selected such that the bend in the catheter sheath  102   c  as it is looped around the sheath guide wheel  108  may not be too sharp as to cause damage to the catheter sheath  102   c.  Further in the various embodiments, various portions of the catheter drive assembly  100  that interact with catheter  102 , such as the catheter support  104 , sheath guide wheel  108 , rollers  110   a,    110   b,  introducer  106   b,  etc., may be sterile components, either sterilizable or disposable, to avoid introducing contaminants into the body of a patient. 
     The rotation of the catheter support  104 , sheath guide wheel  108 , and catheter handle  102   a  clockwise or counterclockwise in the A′ direction about the axis of rotation A may cause the catheter sheath  102   c  of the catheter  102  held by the catheter support  104  to wind and unwind on the sheath guide wheel  108  and move (i.e., back or forth) in the C′ direction along the linear axis C, thereby extending or retracting the catheter sheath  102   c  through the introducer  106   c.  Rotation of the support frame  106  clockwise or counterclockwise in the B′ direction may rotate the support frame  106 , sheath guide wheel  108 , catheter support  104 , and catheter handle  102   a  clockwise or counterclockwise in the B′ direction about the linear axis C, thereby rotating the catheter sheath  102   c  along its axis, which is generally the linear axis C. However, the catheter sheath  102   c  may follow an irregular path. Therefore, the catheter sheath  102   c  will rotate along and about its own axis. Regardless of the rotation of the sheath guide wheel  108  in the A′ direction about the axis of rotation A and/or the rotation of the support frame  106  in the B′ direction around the linear axis C, the catheter handle  102   a  and the catheter support  104  may not move forward or backward in the C′ direction along the linear axis C. In this manner, the catheter sheath  102   c  may be extended or retracted and/or rotated to position the catheter sheath  102   c  as needed within a patient while the catheter drive assembly  100  may remain linearly stationary by not moving in the C′ direction along the linear axis C. 
     To illustrate the rotation of the catheter drive assembly  100 , referring to  FIG. 2 , the catheter drive assembly  100  is illustrated with the support frame  106  rotated 15 degrees in the B′ (e.g., clockwise) direction around the linear axis C and the sheath guide wheel  108  rotated 8 degrees in the A′ direction (e.g., counterclockwise) around the axis of rotation A.  FIG. 2  illustrates that while the catheter support  104 , catheter handle  102   a,  and sheath guide wheel  108  may rotate around the axis of rotation A, the frame support  106  may not and the introducer  106   b  may continue to align the catheter sheath  102   c  in the C′ direction along the linear axis C. Additionally,  FIG. 2  illustrates that while the catheter support  104 , catheter handle  102   a,  and sheath guide wheel  108  may rotate around the axis of rotation A, the catheter support  104 , catheter handle  102   a,  and sheath guide wheel  108  may not move in the C′ direction along the linear axis C. Further, by rotating the sheath guide wheel  108  about the A axis, the catheter sheath  102   c  may be extended (e.g., outfeed) and retracted (e.g., infeed) along the linear axis C while the catheter support  104 , catheter handle  102   a  and sheath guide wheel  108  may remain stationary along the linear axis C. 
       FIG. 3A  illustrates internal components of the catheter drive assembly  100  described above with reference to  FIG. 1  and  FIG. 2  according to one or more embodiments. In some embodiments, the rotator housing  106   a  of the frame support  106  may include a guide wheel motor  302  coupled to the support frame  106  and housed or enclosed by the rotator housing  106   a.  The guide wheel motor  302  may be coupled to the shaft  304 , which is coupled to and supports the catheter support  104 , such as at a central rotational point. When actuated, the guide wheel motor  302  may rotate the shaft  304 . The rotation of the shaft  304  may rotate the catheter support  104 , sheath guide wheel  108 , and catheter handle  102   a  about the shaft  304 , such as about the central rotational point of the catheter support  104  to which the shaft  304  is coupled. A wire  314 , or multiple wires  314 , connected to the guide wheel motor  304  may pass through the frame support  106  to a rotating connector  308  (e.g., a slip ring, commutator, etc.), or multiple connectors  308 , which may be connected to a wire  316 , or multiple wires  316 , in the drive box  114 . The wire or wires  316  may connect to a processor of a catheter positioning system  330 , which may be configured with a power source  335 . The wire or wires  316  may provide control signals and/or may supply power to/from the guide wheel motor  302  via the wire or wires  316 , rotating connector or connectors  308 , and wire or wires  314 . In this manner, a processor  331  of the catheter positioning system  330  may control the actuation of the guide wheel motor  302  and thereby control the extension or retraction of the catheter sheath  102   c  in the direction C′ along the linear axis C. As an example, the processor  331  of the catheter positioning system  330  may be configured with processor-executable instructions, which may be stored in a memory  333  or may be programmed directly into the processor  331  to perform operations to activate the guide wheel motor  302  in response to an input from a remote controller (not shown) connected to the processor  331 . 
     In some embodiments, the drive box  114  may include a frame motor  310  coupled to the support frame  106 . The frame motor  310  may be configured such that rotation of the shaft  312  of the frame motor  310  may rotate the support frame  106 , sheath guide wheel  108 , catheter support  104 , and catheter handle  102   a  in the B′ direction about the linear axis C. In some embodiments, the frame motor  310  may be connected to a wire  315  or wires  315 . The wire  315  or wires  315  may connect to the processor  331  of the catheter positioning system  330  and the power source  335 , and control signals and power may thereby be provided to/from the frame motor  310  via the wire or wires  315 . In this manner, the processor  331  of the catheter positioning system  330  may control the actuation of the frame motor  315  and may thereby control the rotation of the support frame  106 , sheath guide wheel  108 , catheter support  104 , and catheter handle  102   a  in the direction B′ about the linear axis C. As an example, the processor  331  of the catheter positioning system  330  may be configured with processor-executable instructions, which may be stored in the memory  333  or programmed directly into the processor  331 , to perform operations to activate the frame motor  315  in response to an input from a remote controller (not shown) connected to the processor  331 . 
     In some embodiments, the connector port  102   b  may include a wireless transceiver  306  (e.g., a Bluetooth® transceiver) for connecting the catheter  102  to the processor  331  of a catheter positioning system, such as through an RF module  337 . In this manner, the catheter  102  may wirelessly transmit and receive data and commands to and from the processor  331  of the catheter positioning system  330  either in addition to or as an alternative to wired connections  315 ,  316 , etc. In this manner, wired connections from the catheter to the processor may be eliminated. However, power may be supplied via a wired connection. In other embodiments, the catheter  102  may be connected via one or more wire and rotating connector (e.g., one or more wire running from the connector port  102   b  through the catheter support  104 , support frame  106 , and/or drive box  114  with rotating connectors as needed to allow for rotations described above) to the processor  331  of the catheter positioning system  330 . 
       FIG. 3B  illustrates internal components of the catheter drive assembly  100  described above with reference to  FIG. 1  and  FIG. 2  according some embodiments. Although the illustrated embodiment may be similar to that illustrated in  FIG. 3A , in the embodiment illustrated in  FIG. 3B , the guide wheel motor  302  may be located in a portion of the catheter drive assembly  100  not supported by the support frame  106 , such as the drive box  114 . When the guide wheel motor  302  is located remote from the support frame  106 , the guide wheel motor  302  may be coupled to a gear box  322  located in the rotator housing  106   a  of the frame support  106  which may be coupled to the shaft  304 . The guide wheel motor  302  may be coupled to the gear box  322  by a drive shaft  320  extending from the drive box  114  through the support frame  106 . The guide wheel motor  302  may rotate the drive shaft  320 , which may in turn rotate one or more gears of the gear box  322  to rotate the shaft  304 . With the guide wheel motor  302  located in the drive box  114 , the wire  314  and rotating connector  308  shown in  FIG. 3A  may not be needed, and wire  316  may connect directly to the to the guide wheel motor  302 . 
       FIG. 4A  through  FIG. 4C  illustrate translational movement between the rotational movement of an example loop drive  400  in the rotational direction A′ about the rotational axis A and the linear movement of a catheter sheath  402   b  in the linear direction C′ along the linear axis C.  FIG. 4A  illustrates the loop drive  400  in an initial position. The loop drive  400  may include a catheter support  405  that supports a handle  402   a  of a catheter  402 . The catheter support  405  may be coupled to a sheath guide wheel  404 . In the illustrated embodiment, the sheath guide wheel  404  may encircle the catheter support  405 . In other embodiments, the sheath guide wheel  404  may be supported by the catheter support  405  without encircling the support. The catheter support  405  and sheath guide wheel  404  may be supported above a support frame  406 . The support frame  406  may include a rotational housing  406   a  and an introducer  406   b.  The sheath  402   b  of the catheter  402  may extend from the catheter handle  402   a  and through an opening  404   a  in the sheath guide wheel  404 . The sheath  402   b  may loop around an outer edge of the sheath guide wheel  404  in a direction, such as a clockwise direction. While a clockwise direction is illustrated, the sheath  402   b  may be wrapped in the counterclockwise direction. The sheath  402   b  may be wrapped around the perimeter of the sheath guide wheel  404  and may bend around rollers  408   a  and  408   b  such that the sheath  402   b  can extend away from the sheath guide wheel  404  and through the introducer  402   b.  The sheath guide wheel  404  may rotate in either direction of the arc A′ and the sheath  402   b  may extend or retract along the linear axis C. In the initial position illustrated in  FIG. 4A , an example length L of section of sheath  402   b  may extend along the linear axis C from the introducer  406   b.  In some embodiments, the sheath guide wheel  404  may be sterile when in use, because it comes into contact with the sheath  402   b.  As discussed above, the guide wheel  108  may be removable so that after use it may be removed for disposal (i.e., the sheath guide wheel may be a single use component) or for sterilization prior to the next use. Other components, such as elements of the rotational housing (e.g., introducer  406   b ) may also be sterile (and disposable or resterilizable) as they may contact the catheter sheath. 
       FIG. 4B  illustrates the loop drive  400  rotated to a second position from the initial position. The catheter support  405 , catheter handle  402   a,  and sheath guide wheel  404  may have been rotated in a direction A″ along the rotational arc A′ about the A axis. The rotation of the sheath guide wheel  404  in the A″ direction may unspool the sheath  402   b  from around the sheath guide wheel  404 . The rotation of the sheath guide wheel  404  in the A″ direction may extend an end of the sheath  402   b  in an outfeed direction C′ along the linear axis C to a new length L 1  which may be farther from the introducer  406   b  than length L. At greater distances from the introducer  406   b,  the sheath  402   b  may take on curves and loops that cause those portions of the sheath  402   b  to be not straightly aligned with the linear axis C. However, the linear movement of the sheath  402   b  outward from the introducer  406   b  may be translated to linear movement along the entire length of the sheath  402   b  regardless of its localized shape. Thus, the outfeed of the catheter sheath  402   b  from the introducer  406   b  will move the tip of the catheter as well as any implements, irrigation hoses, or other objects a corresponding amount L 1 . 
       FIG. 4C  illustrates the loop drive  400  rotated to a third position from the initial position. The catheter support  405 , catheter handle  402   a,  and sheath guide wheel  404  may be rotated in a direction A′″ along the rotational arc A′ about the A axis. The rotation of the sheath guide wheel  404  in the A′″ direction may wind the sheath  402   b  around the sheath guide wheel  404 . The rotation of the sheath guide wheel  404  in the A′″ direction may thereby retract the end of the sheath  402   b  in an infeed direction C″ along the linear axis C to a new length L 2  which may be less than the length L. As with extending of the sheath  402   b,  the movement of the sheath guide wheel  404  in the A′″ direction may retract the sheath  402   b  along the entire length regardless of the localized shape of the sheath  402   b,  including any instruments coupled the sheath  402   b  and/or the catheter tip. 
       FIG. 5  through  FIG. 7  illustrate a catheter drive assembly  500  including a pinch drive  526  according to embodiments.  FIG. 5  illustrates various external components of the catheter drive assembly  500  from a front perspective view,  FIG. 6  illustrates various external and internal components of the catheter drive assembly  500  from the front perspective view, and  FIG. 7  illustrates various external and internal components of the catheter drive assembly  500  from a different perspective view. 
     Referring to  FIG. 5 , the catheter drive assembly  500  may include a catheter support  504  configured to hold a handle  502   c  of a catheter  502 . The catheter  502  may include catheter controls  502   a  and  502   b  (e.g., rocker arms) which may interface with one or more control actuators  507  and  509  (see  FIG. 6 ) on the catheter support  504 . The control actuators  507  and  509  may move one or both of the catheter controls  502   a  and  502   b  to manipulate the catheter  502 , such as by moving the control arms to cause a movement of a tip of the sheath  502   e  of the catheter  502 . The sheath  502   e  of the catheter  502  may extend through a support frame  506  and connected introducer  508 . The catheter support  504  and pinch drive unit  526  may be rotationally coupled to the support frame  506  such that support frame  506  and pinch drive unit  526  may rotate about the linear axis C. A length of sheath  502   e  not extended out the introducer along the linear axis C, may hang from an opening formed in the catheter support  504  in a loop  502   f.  In an embodiment, a back end of the handle  502   c  of the catheter  502  may include a wired or wireless connector port  502   d  for connecting the catheter  502  to a processor of a catheter positioning system (see, e.g.,  FIGS. 3A and 3B ), thereby enabling the catheter  502  to send/receive data to/from the processor. In some embodiments, elements of the pinch drive unit  526  may be sterile when used because they may come in contact with the catheter  502 . Such elements may be disposable or resterilizable. 
     Referring to  FIG. 6 , the catheter drive assembly  500  may include four motors coupled to the catheter support  504 , including a roller motor  512 , a frame motor  516 , and two actuator motors  514  and  510 . Each actuator motor  510  and  514  may be coupled to its own respective drive shaft  518  and  520 . The drive shafts  518  and  520  may each interface with a respective control actuator  509  and  507 . Actuation of the motor  510  and/or  514  may rotate the drive shaft  518  and/or  520 , respectively, to actuate the control actuator  509  and/or  507 . In an embodiment, actuation of the roller motor  512  may move the shaft  502   e  of the catheter  502  forward or backward in the direction C′ along the linear axis C. In an embodiment, actuation of the frame motor  516  may rotate the pinch drive unit  526 , catheter support  504 , and catheter handle  502   c  clockwise or counterclockwise in the direction B′ about the linear axis C. 
     Referring to  FIG. 7 , the pinch drive unit  526  of the catheter drive assembly  500  may include a first roller  526   a  and a second roller  526   b.  A gear or set of gears  524  may couple the roller motor  512  to the first roller  526   a  and the second roller  526   b.  As an example, a first gear of the set of gears  524  may interface with an end of the first roller  526   a  and a second gear may interface with the first gear of the set of gears  524  and an end of the second roller  526   b.  In this manner, the roller motor  512  may be activated to rotate the first roller  526   a  and the second roller  526   b  in opposite directions. The sheath  502   e  of the catheter  502  may extend between the first roller  526   a  and second roller  526   b.  The first roller  526   a  and second roller  526   b  may be configured to tightly contact or “pinch” the sheath  502   e,  such that rotation of the first roller  526   a  and second roller  526   b  in opposite directions moves the sheath  502   e  back and forth into/out of the introducer  508 . The frame motor  516  may be coupled to a drive wheel  522  which may interface with an inner circumference  506   a  of the support frame  506 . The rotation of the drive wheel  522  by the frame motor  516  may rotate the catheter support  504 , roller motor  524 , first roller  526   a,  second roller  526   b,  set of gears  524 , frame motor  516 , actuator motors  510 ,  514 , catheter handle  502   c,  and other components supported by the catheter support  504  in the direction B′ about the linear axis C. In an embodiment, the first roller  526   a  and/or second roller  526   b  may be eccentric cams enabling the rate of insertion or extraction of the sheath  502   e  into/out of the introducer  508  to vary with the amount of rotation of the first roller  526   a  and/or second roller  526   b.  For example, a first profile of the eccentric cam may allow for faster insertion when the sheath  502   e  is first inserted into a patient and a second profile of the eccentric cam may allow for slower insertion when the sheath  502   e  is near a destination such as the heart of the patient. Various portions of the catheter drive assembly  500  that interact with a catheter  502 , such as the catheter support  504 , rollers  526   a,    526   b,  introducer  508 , etc., may be sterile components, either sterilizable or disposable, to avoid introducing contaminants into the body of a patient. 
     Additionally,  FIG. 7  illustrates that the motors  510 ,  512 ,  514 , and  516  may be connected to wires  534 ,  532 ,  530 , and  528 , respectively. The wires  534 ,  532 ,  530 , and  528  may connect to a processor of a catheter positioning system and/or a power source, and control signals and/or power may be provide to/from the motors  510 ,  512 ,  514 , and  516  via the wires  534 ,  532 ,  530 , and  528 , respectively such as illustrated and described in connection with  FIG. 3A  and  FIG. 3B . As an example, the processor of the catheter positioning system may be configured with processor-executable instructions to perform operations to activate one or more of the motors  510 ,  512 ,  514 , and  516  in response to one or more inputs from a remote controller connected to the processor. 
       FIG. 8A  through  FIG. 8C  illustrate translational movement between rotational movement of the rollers  810   a  and  810   b  of an example pinch drive and linear movement of a catheter sheath  802   b  in the direction C′ along the linear axis C.  FIG. 8A  illustrates the pinch drive in an initial position. The pinch drive may include a catheter support  804  configured to hold a handle  802   a  of a catheter  802 , and a first roller  810   a  and a second roller  810   b  configured to rotate in opposite directions and to pinch the sheath  802   b  of the catheter  802 . The sheath  806  may pass through the rollers  810   a  and  810   b  and may pass through an introducer  808  connected to the support frame  806 . In the initial position illustrated in  FIG. 8A , a length E of sheath  802   b  may extend along the linear axis C from the introducer  808  and a loop  802   c  of the sheath  802   b  may extend a distance D below the support frame  804 . In some embodiments, the first roller  810   a  and the second roller  810   b  may be sterile when in use, due to the potential for contact with the catheter or catheter sheath. The first roller  810   a  and the second roller  810   b  may be removable for disposal after use or for sterilization prior to the next use. 
       FIG. 8B  illustrates a second position in which the rollers  810   a  and  810   b  have rotated in opposite directions (e.g., roller  810   a  in a clockwise direction and  810   b  in a counterclockwise direction). The rotation and pinching action of the rollers  810   a  and  810   b  against the sheath  802   b  may cause the sheath  802   b  to move in an outfeed direction C′ from the introducer  808  along the linear axis C to a new length E 1 , which may be farther from the introducer  808  than length E. Additionally, the extension of the sheath  802   b  from the introducer  808  may reduce the length of the sheath  802   b  in the loop  802   c  below the catheter support  804 , thereby reducing the loop  802   c  of the sheath  802   b  to a distance D 1  below the support frame  804 , which is shorter than the distance D. 
       FIG. 8C  illustrates a third position in which the rollers  810   a  and  810   b  have rotated in opposite directions (e.g., roller  810   a  in a counterclockwise direction and  810   b  in a clockwise direction). The rotation and pinching action of the rollers  810   a  and  810   b  against the sheath  802   b  may cause an end of the sheath  802   b  to move in an infeed direction C″ from the introducer  808  along the linear axis C to a new length E 2  which may be shorter than the length E, e.g. closer to the introducer  808 . Additionally, the retraction of the sheath  802   b  toward the introducer  808  may increase the length of sheath  802   b  in the loop  802   c  below the catheter support  804 , thereby increasing the loop  802   c  of the sheath  802   b  to a distance D 2  below the support frame  804 , which is longer than the distance D. 
       FIG. 9  illustrates a catheter drive assembly  900  (e.g., similar to catheter drive assembly  500  described above with reference to  FIG. 5  through  FIG. 7 ), which may be coupled to a base  904 . The catheter drive assembly  900  may be coupled to a base  904  including various articulating joints  904   b,    904   d,  and arms  904   a,    904   c.  The arm  904   a  may be coupled to the support frame  906  of the catheter drive assembly  900 . In an embodiment, wires  909  for connecting the catheter drive assembly  900  to power, data, etc., to/from the catheter drive assembly  900  (e.g., motor control signals, motor power, catheter data connections, etc.) may pass through the base  904  to the support frame  906 . In an embodiment, the arm  904   a  of the base  904  may be rotationally coupled to the support frame  906  such that the angle of the catheter drive assembly  900  may be rotated about the arm  904   a.  In an embodiment, the arm  904   a  of the base  904  may hold the support frame  906  stationary while a frame motor rotates the catheter support  908  and handle of the catheter  902  about the linear axis. 
       FIG. 10  is a system block diagram of an embodiment catheter positioning system  1000 .  FIG. 10  illustrates a loop drive type catheter drive assembly  1002  including a catheter  1001 . While a loop drive type catheter drive assembly is illustrated, a pinch drive type catheter drive assembly may be substituted without changing the discussion of the operations of the catheter positioning system discussed below with reference to  FIG. 10 . A remote controller  1006  may be connected to a system processor  1004   a  of a programmable control system  1004  by one or more wired connectors  1006   a  or wireless data link  1006   b.  The system processor  1004   a  of the programmable control system  1004  may also be connected to the catheter drive assembly  1002  by one or more wired connector  1002   a  or wireless data link  1002   b.    
     The system processor  1004   a  of the programmable control system  1004  may output control signals to actuate the motors of the catheter drive assembly  1002  based on inputs from the remote controller  1006 . In some embodiments, the output control signals may also be based on training, calibration or programming routines, such as programmed movements for automatic positioning of the catheter  1001 . Programmed movements of the catheter drive assembly  1002  and/or the catheter  1001  may be input prior to a medical procedure, such as by entering commands into the system processor of a programmable control system  1004  (e.g., via a keyboard  1004   b ) or by training the system, such as through manipulation of the remote controller  1006 , such as during a training or calibration sequence. In particular, the processor  1004   a  of the programmable control system  1004  may be configured with processor-executable instructions to issue drive or power commands to each of the motors in the catheter drive assembly  1002  to control the relative rotations of each motor so as to move a catheter&#39;s sheath along a linear axis while holding the catheter handle stationary along that linear axis and/or rotating the catheter handle about the linear axis. 
     The system processor  1004   a  of the programmable control system  1004  may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Alternatively, some operations may be performed by circuitry that is specific to a given function. 
     Those skilled in the art will recognize that the methods and systems of the present invention have many applications, may be implemented in many manners and, as such, are not to be limited by the preceding exemplary embodiments and examples. Additionally, the functionality of the components of the preceding embodiments may be implemented in different manners. Further, it is to be understood that the steps in the embodiments may be performed in any suitable order, combined into fewer steps or divided into more steps. Thus, the scope of the present invention covers conventionally known and future developed variations and modifications to the system components described herein, as would be understood by those skilled in the art.