Abstract:
An apparatus for placing a cardiac support device (CSD) on a heart. The apparatus includes a body, a deployment mechanism on the body for supporting the CSD in an open position for placement on the heart, and a release mechanism coupled to the deployment mechanism for releasably mounting the CSD to the deployment mechanism. The release mechanism includes a release element for releasably engaging the CSD, and a release actuator coupled to the release element for actuating the release element to release the CSD.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 12/638,059 filed on Dec. 15, 2009, which is a continuation of application Ser. No. 11/487,953 filed on Jul. 17, 2006, now U.S. Pat. No. 7,651,462, which is hereby incorporated by reference in its entirety for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention pertains to a method and apparatus for treating congestive heart disease and related valvular dysfunction. More particularly, the present invention is directed to an apparatus and method for delivery of a cardiac support device. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various cardiac support devices for treating congestive heart disease are known. One exemplary type of cardiac support device includes a cardiac jacket for reducing tension in the heart wall by constraining or resisting expansion of the heart. Devices and methods for delivering cardiac support devices using minimally invasive surgical procedures are also known. Such cardiac support devices and/or cardiac support device delivery devices are described, for example, in U.S. Pat. No. 5,702,343; U.S. Pat. No. 6,155,972; U.S. Pat. No. 6,193,648; U.S. Pat. No. 6,293,906; U.S. Pat. No. 6,482,146; U.S. Pat. No. 6,682,476; U.S. Pat. No. 6,902,524; U.S. Pat. No. 6,425,856; U.S. Pat. No. 6,908,426; U.S. Pat. No. 6,572,533; and U.S. Pat. No. 6,951,534, all of which are assigned to Acorn Cardiovascular, Inc. and are incorporated herein by reference. 
         [0004]    Other embodiments of cardiac support devices and/or cardiac support device delivery devices are disclosed in U.S. Pat. No. 6,702,732; U.S. Pat. No. 6,723,041; U.S. patent application publication no. US 2006/0009831 A1 published Jan. 12, 2006; U.S. patent application publication no. US 2005/0288715 published Dec. 29, 2005; U.S. patent application publication no. US 2005/0256368 A1 published Nov. 17, 2005; U.S. patent application publication no. US 2005/0171589 published Aug. 4, 2005; U.S. patent application publication no. US 2005/0090707 A1 published Apr. 28, 2005; and U.S. patent application publication no. US 2005/0059855 A1 published Mar. 17, 2005, all of which are incorporated herein by reference. 
         [0005]    There remains, however, a continuing need for improved delivery devices for cardiac support devices. In particular, there is a need for a delivery device for efficiently and effectively releasing the cardiac jacket over the heart. 
       SUMMARY OF THE INVENTION 
       [0006]    In one embodiment, the present invention is an apparatus for placing a cardiac support device (CSD) on a heart. The apparatus includes a body, a deployment mechanism on the body for supporting the CSD in an open position for placement on the heart, and a release mechanism coupled to the deployment mechanism for releasably mounting the CSD to the deployment mechanism. The release mechanism includes a release element for releasably engaging the CSD, and a release actuator coupled to the release element for actuating the release element to release the CSD. 
         [0007]    In another embodiment, the present invention is an apparatus for placing a cardiac support device (CSD) on a heart. The apparatus includes an elongate body, a deployment mechanism slidably coupled to the body for supporting the CSD, and a release means on the body for releasably coupling the CSD to the deployment mechanism. 
         [0008]    In yet another embodiment, the present invention is a method for deploying a cardiac support device (CSD) about a heart of a patient. The method includes releasably coupling the CSD to a deployment mechanism of a delivery apparatus, positioning the CSD in a desired position about the heart using the delivery apparatus, and actuating a release mechanism to de-couple the CSD and the deployment mechanism. The release mechanism includes a release element coupled to the deployment mechanism and a release actuator coupled to the release element. 
         [0009]    While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows a CSD mounted on an exemplary delivery device that can be used in relation to embodiments of the present invention. 
           [0011]      FIG. 2A  shows a front view of the delivery device of  FIG. 1  in a retracted state. 
           [0012]      FIG. 2B  shows a front view of the delivery device of  FIG. 1  in an extended state. 
           [0013]      FIG. 2C  shows a perspective view of a portion of a control mechanism and release mechanism of  FIG. 1 . 
           [0014]      FIG. 2D  shows a perspective view of the distal ends of the support member and release clement shown in  FIG. 1 . 
           [0015]      FIG. 3A  shows a front view of the release element in relation to the support member of  FIG. 1 . 
           [0016]      FIG. 3B  shows the release element and support member of  FIG. 3A  in relation to a portion of the CSD shown in exploded detail. 
           [0017]      FIG. 4A  shows a front view of a delivery device according to another embodiment of the invention in a retracted state. 
           [0018]      FIG. 4B  shows a front view of the delivery device of  FIG. 4A  in an extended state. 
           [0019]      FIG. 4C  shows a side view of a portion of the control mechanism and release mechanism of  FIG. 4A . 
           [0020]      FIG. 5A  shows a front view of a delivery device according to another embodiment of the invention in a retracted state. 
           [0021]      FIG. 5B  shows a front view of the delivery device of  FIG. 5A  in an extended state. 
           [0022]      FIG. 5C  shows a perspective view of a portion of the release mechanism of  FIGS. 5A . 
           [0023]      FIG. 5D  shows a cross sectional view of a portion of the control mechanism and release mechanism of  FIG. 5A . 
           [0024]      FIG. 6A  shows a front view of a delivery device according to another embodiment of the invention in a retracted state. 
           [0025]      FIG. 6B  shows a front view of the delivery device of  FIG. 6A  in an extended state. 
           [0026]      FIG. 6C  shows a perspective view of a portion of the release mechanism of  FIGS. 6A and 6B . 
           [0027]      FIG. 7A  shows a front view of a delivery device according to another embodiment of the invention in an extended state. 
           [0028]      FIG. 7B  shows a cross-sectional view of the delivery device of  FIG. 7A  taken along line  6 - 6 . 
           [0029]      FIG. 8A  shows a release element and support member according to another embodiment of the present invention coupled to a CSD. 
           [0030]      FIG. 8B  shows the release element and support member of  FIG. 8A  released from the CSD. 
           [0031]      FIG. 9A  shows a release element and support member according to another embodiment of the present invention coupled to a CSD. 
           [0032]      FIG. 9B  shows the release element and support member of  FIG. 9A  released from the CSD. 
           [0033]      FIG. 10A  shows a release element and support member according to another embodiment of the present invention coupled to a CSD. 
           [0034]      FIG. 10  B shows the release element and support member of  FIG. 10A  released from the CSD. 
           [0035]      FIG. 11A  shows a portion of a release mechanism according to another embodiment of the invention. 
           [0036]      FIG. 11B  shows the release mechanism of  FIG. 11A  coupled to a portion of a CSD. 
           [0037]      FIG. 11C  shows the release mechanism of  FIG. 11B  de-coupled from the CSD. 
           [0038]      FIG. 12A  shows a CSD having a release structure according to one embodiment of the invention. 
           [0039]      FIG. 12  B shows a release mechanism according to one embodiment of the present invention in relation to the CSD of  FIG. 12A . 
           [0040]      FIG. 12C  shows a side-sectional view of the CSD of  FIG. 12A  coupled to the release mechanism. 
           [0041]      FIG. 13A  shows a CSD having a release structure according to yet another embodiment of the invention. 
           [0042]      FIG. 13B  shows the release structure of  FIG. 13A  and a release mechanism according to one embodiment of the invention. 
           [0043]      FIG. 13C  shows the actuation of the release mechanism within the release structure shown in  FIG. 13A . 
           [0044]      FIG. 13D  shows the release mechanism de-coupled from the release structure of  FIG. 13A . 
           [0045]      FIG. 14A  shows a release structure and release mechanism according to another embodiment of the present invention. 
           [0046]      FIG. 14B  shows a front view of the release mechanism coupled to the release structure of  FIG. 14A . 
           [0047]      FIG. 14C  shows a front view of the release mechanism de-coupled from the release structure shown in  FIG. 14B . 
           [0048]      FIG. 15A  shows a portion of a release mechanism releasably coupled to a CSD according to another embodiment of the invention. 
           [0049]      FIG. 15B  shows a side view of the release mechanism and CSD of  FIG. 15A . 
           [0050]      FIG. 15C  shows a side view of the release mechanism of  FIG. 15B  released from the CSD. 
           [0051]      FIG. 16A  shows a release structure and release mechanism according to another embodiment of the present invention. 
           [0052]      FIG. 16B  shows a front view of the release mechanism coupled to the release structure of  FIG. 16A . 
           [0053]      FIG. 16C  shows a front view of the release mechanism de-coupled from the release structure shown in  FIG. 16B . 
           [0054]      FIG. 17  shows a detailed and partially sectional view of a support member and release element in accordance with another embodiment of the invention, in an engaged state. 
           [0055]      FIG. 18  shows a detailed view of a portion of the support member and release element shown in  FIG. 17 , in a released state. 
       
    
    
       [0056]    While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0057]      FIG. 1  illustrates a delivery device  100  according to one embodiment of the present invention supporting a cardiac support device (CSD)  104  for deployment over a patient&#39;s heart. The CSD  104  may be any type of cardiac support device, including, without limitation, any of the devices disclosed in any of the patents and patent publications referenced and incorporated herein in the Background of the Invention. In the illustrated embodiment, the CSD  104  includes an open base end  108  and an apex portion  112  having an open apex end  116 . A hem  117  is formed about the open base end  108  of the CSD  104 . 
         [0058]    As shown in  FIG. 1 , the delivery device  100  includes a body  120 , a deployment mechanism  124 , an actuator or a control mechanism  128  on the body  120  operatively coupled to the deployment mechanism  124 , and a release mechanism  132  (see  FIG. 2C ) on the body  120  for releasably coupling the CSD  104  to the deployment mechanism  124 . 
         [0059]    The deployment mechanism  124  is operable to move between a first retracted or closed state, as shown in  FIG. 2A , and a second extended or open state, as shown in  FIG. 1 .  FIG. 2B  shows the deployment mechanism  124  moved to an extended but not opened state. The deployment mechanism  124  is further adapted to releasably support the CSD  104  and to accurately position the CSD  104  at a desired implantation position on the patient&#39;s heart. The deployment mechanism  124  includes at least one elongate support member  136 . In the illustrated embodiment, the deployment mechanism  124  includes eight support members  136 . The invention is not so limited, however, and the deployment mechanism  124  may include a greater or few number of support members  136  in varying configurations. 
         [0060]    The control mechanism  128  drives the deployment mechanism  124  between the retracted and extended states for positioning the CSD  104  on the heart. In the illustrated embodiment, the control mechanism  128  is slidable along a portion of the length of the body  104  to move the support members  136  from the retracted state to the extended state. In the illustrated embodiment, the support members  136  are curved so that the support members  136  form a cup shape to receive the CSD  104  when in the extended state. In other embodiments (not shown), the control mechanism  128  also includes means for spreading apart or otherwise shaping the support members  136  when in the extended state. 
         [0061]    The release mechanism  132  releasably couples the CSD  104  to the deployment mechanism  124 . Thus, once the delivery device  100  has been manipulated to maneuver the CSD  104  into position over or about all or a portion of the heart, the release mechanism  132  is operated to release the CSD  104  from the delivery device  100  onto the heart. The release mechanism  132  includes a release element  140  (see  FIG. 2A ) for releasably engaging the CSD  104  and an actuator mechanism  144  operatively coupled to the release element  140  to control release of the CSD  104  from the release element  140 . 
         [0062]    In the illustrated embodiment, the release element  140  is an elongate member positioned adjacent to each of the support members  136 . A distal end  148  of the release element  140  is movable from an engaged state in which the release element  140  permits the CSD  104  to be mounted to the deployment mechanism  124  and a released state in which the release element  140  releases the CSD  104  from the deployment mechanism  124 . An actuator mechanism  144  is operable to move the release element  140  between the engaged and released states. In the illustrated embodiment, the release elements  140  slide through a channel  156  in the support members  136 . The support members  136  are formed with a plurality of slots  158  to provide incremental advancement of the release elements  140  relative to the support members  136 . 
         [0063]    In the embodiment illustrated in FIGS.  1  and  2 A- 2 D, the control mechanism  128  and the actuator mechanism  144  are integrated into a cylinder  160  positioned about the body  120 . The cylinder  160  slides over a first or main travel region T while moving the all of the support members  136  from the retracted state to the extended state. A second control mechanism  138  including a first user interface  164  is provided for moving individual support members  136  from the retracted state to the extended state. The first user interfaces  164  are individually slidable over a second or supplementary travel region t to move the support members  136 . The release elements  140  remain in the engaged state while the support members  136  are moved from the retracted state to the extended state. 
         [0064]    The actuator mechanism  144  is actuated by sliding a second user interface  168  coupled to the support elements  140  over a third or individual travel region I to move the release elements  140  between engaged and released states. In the illustrated embodiment, the actuator mechanism  144  is operable to actuate the release elements  140  individually. In other embodiments, however, two or more, or all, of the release elements  140  may be actuated as a group. 
         [0065]    As illustrated generally in  FIG. 3A , the CSD  104  includes a release structure  170  releasably engaged by one or both of the deployment mechanism  124  and the release element  140 . The release structure  170  is adapted for coupling to the deployment mechanism  124  for facilitating release of the CSD  104  from the deployment mechanism  124 . In addition, some embodiments of the CSD  104  includes a lubricious element  174 . Lubricious element  174  can also be releasably coupled to the CSD  104  by the release mechanism  132 . Specifically, the release mechanism  132  is operable to de-couple at least a portion of the lubricious element  174  from the CSD  104 . 
         [0066]      FIG. 3B  illustrates the release element  140  in more detail. The release element  140  is in the form of a hook. A release structure  170  in the form of a loop of cord or suture is coupled to the hem  117  of the CSD  104 . In the engaged state, the release structure  170  is coupled to the release element  140  through a hole  157  in the lubricious element  174 . 
         [0067]    The CSD  104  is placed over a patient&#39;s heart with the device  100  as follows. The CSD  104  is mounted to the deployment mechanism  124  with the release elements  140  in the engaged state. The deployment mechanism  124  is put into the retracted state as shown in  FIG. 2A . The delivery device body  120  is manipulated to position the CSD  104  near the heart. The user slides the cylinder  160  distally over the body  120 , advancing the support members  136  from the retracted state to the extended state while the release elements  140  remain in the engaged state. The user may actuate the first user interfaces  164  to move the support members  136  between the retracted and extended states individually to more precisely position the CSD  104  about the heart. 
         [0068]    Once the CSD  104  is maneuvered into the desired position, the actuator mechanisms  144  are actuated by sliding the second user interfaces  168  to move the release elements  140  from the engaged state to the released state to release the CSD  104  from the delivery device  100 . In the engaged state, the release element  140  is retracted within the channel  156  such that the release structure  170  coupled to the release element  140 . Upon movement of the release element  140  to the released state, shown in dashed lines, the release structure  170  is released from the support member  136 . 
         [0069]      FIGS. 4A-4C ,  5 A- 5 D,  6 A- 6 C and  7 A- 7 B illustrate various additional embodiments of the control mechanism  128  and actuator mechanism  144 .  FIGS. 8A-8B ,  9 A- 9 B,  10 A- 10 B,  11 A- 11 C,  12 A- 12 C,  13 A- 13 D and  14 A- 14 C illustrate various additional embodiments of the release element  140  and release stricture  170 . The various embodiments of the control mechanism  128  and actuator mechanism  140  described with respect to  FIGS. 1 ,  2 A- 2 D,  3 A- 3 B,  4 A- 4 C,  5 A- 5 D,  6 A- 6 C and  7 A- 7 B may be used in an combination with the various embodiments of the release element  140  and release structure  170  described with respect to FIGS. a,  2 A- 2 D,  3 A- 3 B,  8 A- 8 B,  9 A- 9 B,  10 A- 10 B,  11 A- 11 C,  12 A- 12 C,  13 A- 13 D and  14 A- 14 C. 
         [0070]      FIGS. 4A-4C  illustrate a delivery device  200  according to another embodiment of the invention showing an alternate release mechanism. As shown in  FIG. 2A , the delivery device  200  includes a body  220 , a deployment mechanism  224 , a control mechanism  228  on the body  220  operatively coupled to the deployment mechanism  224 , and a release mechanism  232  on the body  220  for releasably coupling a CSD (not shown) to the deployment mechanism  224 . 
         [0071]    Similar to previously described embodiments, advancing a cylinder  260  actuates the control mechanism  228 , moving the deployment mechanism  224  from a retracted state as shown in  FIG. 4A  to an extended state as shown in  FIG. 4B . In the illustrated embodiment, the control mechanism  228  is further provided with a locking feature  274  for locking individual advancement of the support members  236 . The locking feature  274  includes protrusions  278  and keyways  282  formed in the cylinder  260 . Rotation of the cylinder  260 , as indicated by arrow  284 , captures the protrusions  278  in the keyways  282 , preventing individual advancement of the support members  236 . 
         [0072]    The release mechanism  232  includes a release element  240  and an actuator mechanism  244 . The actuator mechanism  244  includes a tilting lever arm  286  coupled to a mechanical linkage  290 . Tilting the lever arm  286  forward, as indicated by arrow  292 , pulls the linkage  290  proximally to move the release elements  240  from an engaged state to a released state. The lever arm  286  is also part of the control mechanism  228  and functions as a user interface for advancing the support members  236  individually. 
         [0073]      FIGS. 5A-5D  illustrate a delivery device  300  according to another embodiment of the invention showing an alternate release mechanism. As shown in  FIG. 5A , the delivery device  300  includes a body  320 , a deployment mechanism  324 , a control mechanism  328  on the body  320  operatively coupled to the deployment mechanism  324 , and a release mechanism  332  on the body  320  for releasably coupling a CSD (not shown) to the deployment mechanism  324 . 
         [0074]    Similar to previously described embodiments, advancing a cylinder  360  actuates the control mechanism  328 , moving the deployment mechanism  324  from a retracted state as shown in  FIG. 5A  to an extended (but not opened) state as shown in  FIG. 5B . The control mechanism  324  further includes user interface buttons  364  for individually advancing the support members  336  and release elements  340 . 
         [0075]    The release mechanism  332  includes a release element  340  and an actuator mechanism  344 . The actuator mechanism  344  includes a rotating actuator cylinder  391  that is coupled to all of the release elements  340 . The actuator mechanism  344  is operable to move all of the release elements  340  from an engaged state to a release state in unison upon rotation of the actuator cylinder  391 . The release elements  340  each have an engagement pin  392  that is synchronized with axial teeth  393  in the actuator cylinder  391 . Rotational movement of the actuator cylinder  391  captures the engagement pins  392  at various positions of individual adjustment of the support members  336 . A keyway  394  in the cylinder  360  controls rotation and forward movement of the actuator cylinder  391 . 
         [0076]      FIGS. 6A-6C  illustrate another embodiment of a delivery device  400  showing an alternative release mechanism. As shown in  FIG. 6A , the delivery device  400  includes a body  420 , a deployment mechanism  424 , a control mechanism  428  on the body  420  operatively coupled to the deployment mechanism  424 , and a release mechanism  432  on the body  420  for releasably coupling a CSD (not shown) to the deployment mechanism  424 . 
         [0077]    The release mechanism  432  includes a release element  440  and an actuator mechanism  444 . Similar to previously described embodiments, advancing a cylinder  460  actuates the control mechanism  424 , moving the deployment mechanism  424  from a retracted state as shown in  FIG. 6A  to an extended state as shown in  FIG. 6B . 
         [0078]      FIGS. 7A and 7B  illustrate another embodiment of a delivery device  500  showing an alternative release mechanism. As shown in  FIG. 7A , the delivery device  500  includes a body  520 , a deployment mechanism  524 , a control mechanism  528  on the body  520  operatively coupled to the deployment mechanism  524 , and a release mechanism  532  on the body  520  for releasably coupling a CSD (not shown) to the deployment mechanism  524 . A suction cup  525  for releasably engaging a patient&#39;s heart is connected to a vacuum source (not shown) though tube  527 . Actuator mechanism  544  is operated in a manner similar to that of the above-described embodiments to move the deployment mechanism  524  from a retracted position (not shown) to the extended and open position shown in  FIGS. 7A and 7B . The support members  536  can be formed resilient members, and can be guided at least in part from their retracted positions to the extended and open positions shown in  FIGS. 7A and 7B  by the suction cup  525 . 
         [0079]      FIGS. 8A and 8B  illustrate a support member  736 , release element  740  and release structure  770  according to another embodiment of the invention. The release element  740  includes an opening  741 . The release structure  770  is in the form of a loop of cord or suture that is threaded through a portion of the CSD  104 , with a first end  771  coupled to the delivery device  100  and a second end  772  that is free. When the release element  740  is in the engaged state, as shown in  FIG. 8A , the free end  772  of the release structure  770  is inserted through the hole  741  and the release element  740  is retracted within the support member  736 . The free end  772  of the release structure  770  is thus captured between the release element  740  and the support member  736 , coupling the CSD  104  to the support member  736 . When the release element  740  is moved to the released state, shown in  FIG. 8B , the release element  740  is advanced distally relative to the support member  736 , releasing the release structure  770 . The release structure  770  is easily pulled through the hole  741  and the CSD  104  as the support member  736  is withdrawn. 
         [0080]      FIGS. 9A and 9B  illustrate a release element  840  and release structure  870  according to another embodiment of the present invention. The release element  840  is in the form of a hook. The release structure  870  is in the form of a loop of cord or suture having ends  871 ,  872  coupled to the CSD  104 . The release structure  870  is captured by the hook of the release element  840  and coupled to the support member  836  when the release element  840  is in the engaged state, as shown in  FIG. 9A . When the release element  840  is moved to the released state, as shown in  FIG. 9B , the release structure  870  is released to de-couple the support member  836  and the CSD  104 . 
         [0081]      FIGS. 10A and 10B  illustrate a release element  940  and release structure  970  according to another embodiment of the present invention. The release element  940  is in the form of a pair of pincers  943 , while the release structure  970  is in the form of a loop of cord or suture having a portion  773  coupled to the CSD  104 . When the release element  932  is in the engaged state, the release element  932  is retracted within the support member  936 , causing the pincers  943  to be pinched together, thus capturing the release structure  970 , as shown in  FIG. 10A . When the release element  940  is moved to the released state, as shown in  FIG. 10B , the release structure  970  is advanced distally relative to the support member  936  and the pincers  943  spread apart to release the release structure  970 . 
         [0082]      FIGS. 11A-11C  illustrate a support member  1036 , release element  1040  and release structure  1070  configuration according to another embodiment of the present invention. The release element  1040  is in the form of a flat rod received within a channel  1056  formed by the support member  1036 . A distal end of the support member  1036  includes an opening  1037 . The release structure  1070  is in the form of a flexible band formed around at least a portion of the CSD  104 . In the engaged state, the release structure  1070  is received in the opening  1037  and held in place by the release element  1040  which is positioned at the opening  1037  (see  FIG. 11B ). Upon movement of the release element  1040  from the engaged state, shown in  FIG. 11B , to the release state, shown in  FIG. 11C , the release element  1040  is moved proximally within the channel  1057  to release the release structure  1070  from the support member  1036 . 
         [0083]      FIGS. 12A-12C  illustrate a support member  1136 , release element  1140  and release structure  1170  according to another embodiment of the invention. The release structure  1170  is in the form of protrusions on the hem  117  of the CSD  104  and each has an opening  1171  therethrough (see  FIG. 12A ). As shown in  FIG. 12C , the support member  1136  has a distal recess  1137  sized and shaped to receive the release structure  1170 . The release element  1140  is in the form of a slender rod sized to be received in the opening  1171 . In the engaged state, shown in  FIG. 12B , the release structures  1170  are positioned within the recesses  1137  and the release elements  1140  are inserted into the openings  1171  to hold the release structures  1170  in place. Upon movement of the release element  1140  from the engaged state, to the release state, shown in dashed lines in  FIG. 12C , the release element  1140  is withdrawn proximally out of the opening  1171  to release the release structure  1170  from the recesses  1137 . 
         [0084]      FIGS. 13A-D  illustrate a release element  1240 , support member  1236  and release structure  1270  according to another embodiment of the invention. The release structure  1270  is in the form of a lock housing positioned on the hem  117  of the CSD  104 . A hook  1272  is formed within the release structure  1270 . The release structure  1270  further has a passageway  1271  for receiving the release element  1240 . In the engaged state, shown in  FIG. 13B  (release structure shown opened for clarity), the release element  1240  is captured on the hook  1272 . Upon movement of the release element  1240  from the engaged state, shown in solid lines in  FIG. 13C , to a release state, shown in dashed lines, the release element  1240  disengages from the hook  1272 , allowing the release element  1240  to be withdrawn proximally through the passageway  1271  (see  FIG. 13D ). 
         [0085]      FIGS. 14A-14C  illustrate a release element  1340 , support member  1336  and release structure  1370  according to another embodiment of the invention. The support member  1336  includes a U-shaped yoke  1338  defining an opening  1339 . The release element  1340  is movable from an engaged state, in which the release element  1340  is proximal to the opening  1339  (see  FIG. 14B ), to a release state, in which the release element  1340  is positioned within the opening  1339  (see  FIG. 14C ). The release structure  1370  is in the form of a projection sized and shaped to be snugly received within the yoke  1338 . Movement of the release element  1340  from the engaged state, shown in  FIG. 14B , to the release state, shown in  FIG. 14C , ejects the release structure  1370  from the yoke  1338 . 
         [0086]      FIGS. 15A-15C  illustrate a portion of a release element  1440 , support member  1436  and release structure  1470  according to another embodiment of the invention. The release structure  1470  is in the form of a length of cord or suture that is threaded through the CSD  104 . The support member  1436  includes a pair of distal openings  1437  divided by a support bridge  1438 . The release element  1440  includes a cutting surface  1441 . In the engaged state, shown in  FIGS. 15A and 15B , the release element  1440  is positioned proximally to the openings  1437 . The release structure  1470  is threaded through the openings  1437  and tied over the bridge  1438  to couple the CSD  104  to the support member  1436 . Upon movement of the release element  1440  to the release state, shown in  FIG. 15C , the release element  1440  is moved distally over the release structure  1470  to cut the release structure  1470 , thus releasing the CSD  104  from the support member  1436 . 
         [0087]      FIGS. 16A-16C  illustrate a support member  1336 ′ and release structure  1370 ′ according to another embodiment of the invention. The support member  1336 ′ and release structure  1370 ′ can be substantially the same or similar to support member  1336  and release structure  1370  described above in connection with  FIGS. 14A-14C , and similar features are identified by similar reference numbers. Unlike the embodiment of the invention shown in  FIGS. 14A-14C , the embodiment shown in  FIGS. 16A-16C  does not include a release element  1340 . Instead and as described in greater detail below, support member  1336 ′ is passively disengaged from the release structure  1370 ′. The support member  1336 ′ includes a C- or U-shaped yoke  1338 ′ defining an opening  1339 ′. The release structure  1370 ′ is in the form of a projection sized and shaped to be snugly received within the yoke  1338 ′. Yoke  1338 ′ is formed of resilient material that enables the yoke to sufficiently deform and “snap” onto the release structure  1370 ′ (e.g., to diametrically expand and then return to its original shape). The characteristics of the yoke  1338 ′ in cooperation with the release structure  1370 ′ provides sufficient strength to enable the yoke to remain attached to the release structure while CSD  104  is positioned on the patient&#39;s heart. Following positioning of the CSD  104 , movement of the support member  1336 ′ in a direction opposite the opening in the yoke  1338 ′ causes the yoke to deform and disengage from the release structure  1370 ′. The support member  1336 ′ is thereby passively released from the CSD  104  since it was the motion of the support member itself, rather than another structure, that causes the release action. 
         [0088]      FIGS. 17 and 18  illustrate a support member  1536  and release element  1540  according to another embodiment of the invention. The support member  1536  is a tubular structure having an opening  1556  on its distal end. The release element  1540  is an elongate member movable within the support member  1536  between retracted and extended positions. A finger on the distal end  1548  of the release element  1540  has a tang  1551  and an inner element  1553  that cooperate to provide a functional engagement portion. The distal end  1548  is formed with the tang  1551  and inner element  1553  separated and spaced from one another when the release element  1540  is in its released state shown in  FIG. 18  with the distal end  1548  extending from the opening  1556  of the support member  1536 . The tang  1551  is formed of flexible and resilient material, enabling the tang to be deformed from its free or native state into the hook shape of the capture position shown in  FIG. 17 . When release element  1540  is in the engaged state shown in  FIG. 17 , the tang  1551  is retained in the capture position adjacent to inner element  1553 . 
         [0089]    The tang  1551  of release element  1540  can engage a release structure such a suture loop (not shown) on a CSD (also not shown) when the release element is in the engaged state. When moved to the released state shown in  FIG. 18 , the tang  1551  will return to its native state to release the release structure. Locating the tang  1551  and inner element  1553  at the opening  1556  on the distal end of the support member  1536  can enhance the accuracy by which the CSD can be positioning on the patient&#39;s heart. 
         [0090]    Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.