Abstract:
An apparatus for reducing mitral regurgitation includes a delivery catheter extendable through a vascular system of a patient and into a coronary sinus proximate a posterior leaflet of a mitral valve, the catheter having at a distal end thereof a flexible tubular extension for engaging an opening of the coronary sinus and entering the coronary sinus, a substantially rigid body for advancement through the delivery catheter and to be positioned in the coronary sinus proximate the posterior leaflet, and an elongated rod for advancing the body through the catheter and into position proximate the posterior leaflet.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATIONS  
       [0001]    This patent application:  
         [0002]    (1) is a continuation-in-part of pending prior U.S. patent application Ser. No. 10/068,264, filed Feb. 5, 2002 by Daniel C. Taylor et al. for METHOD AND APPARATUS FOR IMPROVING MITRAL VALVE FUNCTION (Attorney&#39;s Docket No. VIA-29);  
         [0003]    (2) is a continuation-in-part of pending prior U.S. patent application Ser. No. 10/112,354, filed Mar. 29, 2002 by John Liddicoat et al. for METHOD AND APPARATUS FOR IMPROVING MITRAL VALVE FUNCTION (Attorney&#39;s Docket No. VIA-19202122);  
         [0004]    (3) claims benefit of pending prior U.S. Provisional Patent Application Serial No. 60/312,217, filed Aug. 14, 2001 by Daniel C. Taylor et al. for METHOD AND APPARATUS FOR TEMPORARY IMPROVEMENT IN MITRAL VALVE FUNCTION (Attorney&#39;s Docket No. VIA-23 PROV);  
         [0005]    (4) claims benefit of pending prior U.S. Provisional Patent Application Serial No. 60/339,481, filed Oct. 26, 2001 by William E. Cohn et al. for TRANSVASCULAR APPROACH TO MITRAL VALVE PROCEDURES (Attorney&#39;s Docket No. VIA-30 PROV); and  
         [0006]    (5) claims benefit of pending prior U.S. Provisional Patent Application Serial No. 60/348,424, filed Jan. 14, 2002 by Daniel C. Taylor et al. for METHOD AND APPARATUS TO IMPROVE MITRAL VALVE FUNCTION (Attorney&#39;s Docket No. VIA-31 PROV).  
         [0007]    The aforementioned five (5) patent applications are hereby incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0008]    This invention relates to surgical methods and apparatus in general, and more particularly to surgical methods and apparatus for improving mitral valve function.  
         BACKGROUND OF THE INVENTION  
         [0009]    Mitral valve repair is the procedure of choice to correct mitral regurgitation of all etiologies. With the use of current surgical techniques, between 70% and 95% of regurgitant mitral valves can be repaired. The advantages of mitral valve repair over mitral valve replacement are well documented. These include better preservation of cardiac function and reduced risk of anticoagulant-related hemorrhage, thromboembolism and endocarditis.  
           [0010]    In current practice, mitral valve surgery requires an extremely invasive approach that includes a chest wall incision, cardiopulmonary bypass, cardiac and pulmonary arrest, and an incision on the heart itself to gain access to the mitral valve. Such a procedure is associated with high morbidity and mortality. Due to the risks associated with this procedure, many of the sickest patients are denied the potential benefits of surgical correction of mitral regurgitation. In addition, patients with moderate, symptomatic mitral regurgitation are denied early intervention and undergo surgical correction only after the development of cardiac dysfunction.  
           [0011]    Mitral regurgitation is a common occurrence in patients with heart failure and a source of important morbidity and mortality in these patients. Mitral regurgitation in patients with heart failure is caused by changes in the geometric configurations of the left ventricle, papillary muscles and mitral annulus. These geometric alterations result in incomplete coaptation of the mitral leaflets during systole. In this situation, mitral regurgitation is corrected by plicating the mitral valve annulus, either by sutures alone or by sutures in combination with a support ring, so as to reduce the circumference of the distended annulus and restore the original geometry of the mitral valve annulus.  
           [0012]    More particularly, current surgical practice for mitral valve repair generally requires that the mitral valve annulus be reduced in radius by surgically opening the left atrium and then fixing sutures, or more commonly sutures in combination with a support ring, to the internal surface of the annulus; this structure is used to pull the annulus back into a smaller radius, thereby reducing mitral regurgitation by improving leaflet coaptation.  
           [0013]    This method of mitral valve repair, generally termed “annuloplasty”, effectively reduces mitral regurgitation in heart failure patients. This, in turn, reduces symptoms of heart failure, improves quality of life and increases longetivity. Unfortunately, however, the invasive nature of mitral valve surgery and the attendant risks render most heart failure patients poor surgical candidates. Thus, a less invasive means to increase leaflet coaptation and thereby reduce mitral regurgitation in heart failure patients would make this therapy available to a much greater percentage of patients.  
           [0014]    Mitral regurgitation also occurs in approximately 20% of patients suffering acute myocardial infarction. In addition, mitral regurgitation is the primary cause of cardiogenic shock in approximately 10% of patients who develop severe hemodynamic instability in the setting of acute myocardial infarction. Patients with mitral regurgitation and cardiogenic shock have about a 50% hospital mortality. Elimination of mitral regurgitation in these patients would be of significant benefit. Unfortunately, however, patients with acute mitral regurgitation complicating acute myocardial infarction are particularly high-risk surgical candidates, and are therefore not good candidates for a traditional annuloplasty procedure. Thus, a minimally invasive means to effect a temporary reduction or elimination of mitral regurgitation in these critically ill patients would afford them the time to recover from the myocardial infarction or other acute life-threatening events and make them better candidates for medical, interventional or surgical therapy.  
         SUMMARY OF THE INVENTION  
         [0015]    As a result, one object of the present invention is to provide an improved method and apparatus for reducing mitral regurgitation.  
           [0016]    Another object of the present invention is to provide a method and apparatus for reducing mitral regurgitation which is minimally invasive.  
           [0017]    Another object of the present invention is to provide a method and apparatus for reducing mitral regurgitation which can be deployed either permanently (e.g., for patients suffering from heart failure) or temporarily (e.g., for patients suffering from mitral regurgitation with acute myocardial infarction).  
           [0018]    These and other objects are addressed by the present invention, which comprises an improved method and apparatus for reducing mitral regurgitation.  
           [0019]    In one form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting apparatus into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the apparatus being adapted to straighten the natural curvature of at least a portion of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0020]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting apparatus into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the apparatus being adapted to move at least a portion of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve anteriorly, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0021]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting apparatus into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the apparatus being adapted to reduce the degree of natural curvature of at least a portion of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0022]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting apparatus into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the apparatus being adapted to increase the natural radius of curvature of at least a portion of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0023]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting apparatus into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the apparatus having a distal end, a proximal end and an intermediate portion, the apparatus being configured so that when the apparatus is positioned in the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, the distal and proximal ends will apply a posteriorly-directed force to the walls of the coronary sinus and the intermediate portion will apply an anteriorly-directed force to the walls of the coronary sinus, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0024]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting a substantially straight elongated body into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the length of the substantially straight elongated body being sized relative to the natural curvature of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve so that when the substantially straight elongated body is positioned in the coronary sinus, it will cause at least a portion of the coronary sinus to assume a substantially straight configuration adjacent to the posterior leaflet of the mitral valve, whereby to increase the radius of curvature of the mitral annulus and thereby improve leaflet coaptation.  
           [0025]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting a substantially rigid elongated body into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the substantially rigid elongated body being configured relative to the natural curvature of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve so that when the substantially rigid elongated body is positioned in the coronary sinus, it will cause at least a portion of the coronary sinus to assume a different configuration adjacent to the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0026]    In another form of the invention, there is provided a method for reducing mitral regurgitation comprising: inserting a straight, substantially rigid elongated body into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the length of the straight, substantially rigid elongated body being sized relative to the natural curvature of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve so that when the straight, substantially rigid elongated body is positioned in the coronary sinus, it will cause at least a portion of the coronary sinus to assume a substantially straight configuration adjacent to the posterior leaflet of the mitral valve, whereby to increase the radius of curvature of the mitral annulus and thereby improve leaflet coaptation.  
           [0027]    In another form of the invention, there is provided an apparatus for reducing mitral regurgitation comprising: a body having a distal end, a proximal end and an intermediate portion, the body being configured so that when the body is positioned in the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, the distal and proximal ends will apply a posteriorly-directed force to the walls of the coronary sinus, and the intermediate portion will apply an anteriorly-directed force to the walls of the coronary sinus, whereby to move the posterior annulus of the mitral valve anteriorly and thereby improve leaflet coaptation.  
           [0028]    In another form of the invention, there is provided an apparatus for reducing mitral regurgitation comprising: a substantially straight elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the length of the substantially straight elongated body being sized relative to the natural curvature of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve so that when the substantially straight elongated body is positioned in the coronary sinus, it will cause at least a portion of the coronary sinus to assume a substantially straight configuration adjacent to the posterior leaflet of the mitral valve, whereby to increase the radius of curvature of the mitral annulus, moving it anteriorly, and thereby improve leaflet coaptation.  
           [0029]    In another form of the invention, there is provided an apparatus for reducing mitral regurgitation comprising: a substantially rigid elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the length of the straight, substantially rigid elongated body being sized relative to the natural curvature of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve so that when the substantially rigid elongated body is positioned in the coronary sinus, it will cause at least a portion of the coronary sinus to assume a different configuration adjacent to the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
           [0030]    In another form of the invention, there is provided an apparatus for reducing mitral regurgitation comprising: a straight, substantially rigid elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the length of the straight, substantially rigid elongated body being sized relative to the natural curvature of the coronary sinus in the vicinity of the posterior leaflet of the mitral valve so that when the straight, substantially rigid elongated body is positioned in the coronary sinus, it will cause at least a portion of the coronary sinus to assume a substantially straight configuration adjacent to the posterior leaflet of the mitral valve, whereby to increase the radius of curvature of the mitral annulus, moving it anteriorly, and thereby improve leaflet coaptation.  
           [0031]    Significantly, the present invention may be practiced in a minimally invasive manner, either permanently or temporarily, so as to reduce mitral regurgitation. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]    These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:  
         [0033]    [0033]FIG. 1 is a schematic view of portions of the human vascular system;  
         [0034]    [0034]FIG. 2 is a schematic view of portions of the human heart;  
         [0035]    [0035]FIG. 3 is a schematic view of a preferred system formed in accordance with the present invention;  
         [0036]    FIGS.  4 - 7  are a series of views illustrating use of the system of FIG. 3 to reduce mitral regurgitation;  
         [0037]    [0037]FIG. 8 shows an alternative form of delivery catheter;  
         [0038]    [0038]FIG. 9 shows an alternative form of flexible push rod;  
         [0039]    [0039]FIG. 9A shows another alternative form of the present invention;  
         [0040]    [0040]FIG. 9B is a diagrammatic side elevational partly sectioned view of a further flexible push rod;  
         [0041]    [0041]FIGS. 9C and 9D are similar to FIG. 9B and showing alternative embodiments of flexible push rod;  
         [0042]    [0042]FIG. 9E is a generally side elevational view of a flexible guiding catheter;  
         [0043]    [0043]FIGS. 10 and 11 show alternative constructions for the straight, substantially rigid elongated body;  
         [0044]    [0044]FIG. 11A illustrates another aspect of the present invention;  
         [0045]    [0045]FIG. 12 shows an alternative system formed in accordance with the present invention;  
         [0046]    [0046]FIG. 13 shows use of the system shown in FIG. 12;  
         [0047]    FIGS.  14 - 16  illustrate another aspect of the present invention;  
         [0048]    [0048]FIG. 16A illustrates another aspect of the present invention;  
         [0049]    [0049]FIG. 16B illustrates still another aspect of the present invention;  
         [0050]    FIGS.  17 - 20  illustrate still other aspects of the present invention;  
         [0051]    FIGS.  21 - 24  illustrate other aspects of the present invention;  
         [0052]    FIGS.  25 - 27  illustrate another form of the present invention;  
         [0053]    FIGS.  28 - 32  illustrate the embodiment of FIGS.  25 - 27  in use;  
         [0054]    FIGS.  32 A- 32 C illustrate another aspect of the present invention;  
         [0055]    [0055]FIGS. 32D and 32E illustrate another aspect of the present invention;  
         [0056]    [0056]FIGS. 33 and 34 illustrate another form of the present invention;  
         [0057]    FIGS.  35 - 37  illustrate the embodiment of FIGS. 33 and 34 in use;  
         [0058]    FIGS.  37 A- 37 C illustrate another aspect of the present invention;  
         [0059]    [0059]FIGS. 37D and 37E illustrate another aspect of the present invention;  
         [0060]    FIGS.  37 F- 37 I illustrate another aspect of the present invention;  
         [0061]    [0061]FIGS. 37J and 37K illustrate yet another aspect of the present invention; FIG. 38 illustrates another form of the present invention;  
         [0062]    [0062]FIGS. 39 and 40 illustrate the embodiment of FIG. 38 in use;  
         [0063]    [0063]FIGS. 41 and 42 illustrate yet another form of the present invention; and  
         [0064]    [0064]FIGS. 43 and 44 illustrate still another aspect of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0065]    The coronary sinus is the largest vein in the human heart. During a large portion of its course in the atrioventricular groove, the coronary sinus typically extends adjacent to the left atrium of the heart for a distance of approximately 5 to 10 centimeters. Significantly, for a portion of its length, e.g., typically approximately 7-9 cm, the coronary sinus extends substantially adjacent to the posterior perimeter of the mitral annulus. The present invention takes advantage of this consistent anatomic relationship. More particularly, by deploying novel apparatus in the coronary sinus, adjacent to the posterior leaflet of the mitral valve, the natural curvature of the coronary sinus may be modified in the vicinity of the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly so as to improve leaflet coaptation and, as a result, reduce mitral regurgitation.  
         [0066]    In one preferred embodiment of the invention, the novel apparatus comprises a straight, substantially rigid elongated body, the length of the straight, substantially rigid elongated body being sized so that when the straight, substantially rigid body is positioned in the coronary sinus in the vicinity of the posterior leaflet of the mitral valve, the straight, substantially rigid elongated body will cause at least a portion of the coronary sinus to assume a substantially straight configuration adjacent to the posterior leaflet of the mitral valve, whereby to move the posterior annulus anteriorly and thereby improve leaflet coaptation.  
         [0067]    And in one preferred embodiment of the invention, access to the coronary sinus is gained percutaneously, e.g., the straight, substantially rigid elongated body is introduced into the patient&#39;s vascular system via the jugular vein or via the left subclavian vein, passed down the superior vena cava, passed through the right atrium and then passed into the coronary sinus, where it is deployed. Alternatively, the straight, substantially rigid elongated body may be introduced into the coronary sinus through a small incision in the heart, or through some other incision into the patient&#39;s vascular system.  
         [0068]    And in one preferred embodiment of the invention, the straight, substantially rigid elongated body is guided into position by (i) passing it through a pre-positioned catheter, or (ii) passing it over a pre-positioned guidewire, or (iii) passing it guide-free (e.g., on the end of a steerable delivery tool) to the surgical site.  
         [0069]    Once deployed, the novel apparatus may be left in position permanently (e.g., in the case of patients suffering from mitral regurgitation associated with heart failure) or the novel apparatus may be left in position only temporarily (e.g., in the case of patients suffering from mitral regurgitation associated with acute myocardial infarction).  
         [0070]    Visualization of the procedure may be obtained by fluoroscopy, echocardiography, intravascular ultrasound, angioscopy, real-time magnetic resonance imaging, etc. The efficacy of the procedure may be determined through echocardiography, although other imaging modalities may also be suitable.  
         [0071]    Looking now at FIGS. 1 and 2, there are shown aspects of the cardiovascular system  3  of a patient. More particularly, cardiovascular system  3  generally comprises the heart  6 , the superior vena cava  9  (FIG. 1), the right subclavian vein  12 , the left subclavian vein  15 , the jugular vein  18 , and the inferior vena cava  21 . Superior vena cava  9  and inferior vena cava  21  communicate with the heart&#39;s right atrium  24  (FIGS. 1 and 2). The coronary ostium  27  leads to coronary sinus  30 . At the far end  31  (FIG. 2) of coronary sinus  30 , the vascular structure turns into the vertically-descending anterior interventricular vein (“AIV”)  32  (FIG. 1). For purposes of the present invention, it can generally be convenient to consider the term “coronary sinus” to mean the vascular structure extending between coronary ostium  27  and AIV  32 .  
         [0072]    As seen in FIG. 2, between coronary ostium  27  and AIV  32 , coronary sinus  30  generally extends substantially adjacent to the posterior perimeter of the annulus  33  of the mitral valve  36 . Mitral valve  36  comprises a posterior leaflet  39  and an anterior leaflet  42 . In the case of a regurgitant mitral valve, posterior leaflet  39  and anterior leaflet  42  will generally fail to properly coapt at systole, thereby leaving an intervening gap  45  which will permit regurgitation.  
         [0073]    Looking next at FIG. 3, there is shown a system  100  which comprises one preferred embodiment of the present invention. More particularly, system  100  generally comprises a guidewire  103 , a delivery catheter  106  and a push rod  109 .  
         [0074]    Guidewire  103  comprises a flexible body  112  having a distal end  115  and a proximal end  118 . The distal end  115  of guidewire  103  preferably includes a spring tip  121  for allowing the distal end of guidewire  106  to atraumatically traverse vascular structures, i.e., while the guidewire is being passed through the vascular system of a patient.  
         [0075]    Delivery catheter  106  comprises a flexible body  124  having a distal end  127  and a proximal end  130 , preferably with an adjustable valve  133  attached. A central lumen  136  extends from distal end  127  to proximal end  130 . In some circumstances it may be desirable to provide a securing mechanism for securing the distal end of the delivery catheter within a vascular structure. By way of example but not limitation, a balloon  139  may be positioned about the exterior of flexible body  124 , just proximal to distal end  127 , with an inflation lumen  142  extending between balloon  139  and an inflation fitting  145 .  
         [0076]    Push rod  109  comprises a flexible body  148  having a distal end  151  and a proximal end  154 . A straight, substantially rigid elongated body  157 , which may have a variety of different lengths, is formed on flexible body  148 , proximal to distal end  151 . A removable proximal stiffener or handle  160  may be placed between straight, substantially rigid elongated body  157  and proximal end  154 .  
         [0077]    System  100  may be used as follows to reduce mitral regurgitation.  
         [0078]    First, distal end  115  of guidewire  103  is passed down the jugular vein  18  (or the left subclavian vein  15 ) of a patient, down superior vena cava  9 , through right atrium  24  of the heart, and then into coronary sinus  30 . See FIG. 4. It will be appreciated that as flexible guidewire  103  is passed down coronary sinus  30 , the guidewire will tend to assume the natural curved shape of the coronary sinus, due to the flexible nature of the guidewire. The guidewire&#39;s atraumatic spring tip  121  will help ensure minimal damage to vascular structures as guidewire  103  is maneuvered into position.  
         [0079]    Next, distal end  127  of delivery catheter  106  is placed over proximal end  118  of guidewire  103  and passed down the guidewire until the distal end of the delivery catheter is positioned in coronary sinus  30 . See FIG. 5. Again, it will be appreciated that as the flexible delivery catheter  106  passes down the coronary sinus, the delivery catheter will tend to assume the natural curved shape of the coronary sinus, due to the flexible nature of the delivery catheter.  
         [0080]    Once delivery catheter  106  has been positioned within the coronary sinus, guidewire  103  is removed. See FIG. 6. Either before or after guidewire  103  is removed, balloon  139  may be inflated so as to secure distal end  127  of delivery catheter  106  in position within coronary sinus  30 .  
         [0081]    Next, push rod  109  is passed down the central lumen  136  of delivery catheter  106 . As the push rod&#39;s straight, substantially rigid elongated body  157  is passed down central lumen  136  of delivery catheter  106 , it will force the delivery catheter to assume a straight configuration at the point where the straight, substantially rigid elongated body  157  currently resides. As push rod  109  is pushed down delivery catheter  106 , balloon  139  will hold the distal end of the delivery catheter in position within coronary sinus  30 .  
         [0082]    Push rod  109  is pushed down delivery catheter  106 , utilizing removable proximal stiffener  160  as needed, until the straight, substantially rigid elongated body  157  is located adjacent to the posterior annulus of mitral valve  36 . See FIG. 7. As this occurs, the presence of the straight, substantially rigid elongated body  157  in delivery catheter  106  will cause at least a portion of coronary sinus  30  to assume a substantially straight configuration at this point, so that the posterior annulus of mitral valve  36  is forced anteriorly. This will cause the mitral valve&#39;s posterior leaflet  39  to also move anteriorly so as to improve mitral valve leaflet coaptation and thereby reduce (or completely eliminate) mitral valve regurgitation. In this respect it should be appreciated that the posterior annulus may be shifted anteriorly so as to achieve, or to attempt to achieve to the extent anatomically possible, leaflet-to-leaflet engagement or leaflet-to-annulus engagement (e.g., where a leaflet may be tethered due to left ventricular distortion). Both of these types of engagement, or targeted engagement, are intended to be encompassed by the terms “improved leaflet coaptation” and/or “increased leaflet coaptation” and the like. Using standard visualization means (e.g. echocardiography or fluoroscopy), the exact position of the straight, substantially rigid elongated body  157  is adjusted so as to reduce (or completely eliminate) regurgitation in mitral valve  36 .  
         [0083]    In this respect it should be appreciated that the straight, substantially rigid elongated body  157  is preferably sized to be somewhat less than the length of the coronary sinus between coronary ostium  27  and AIV  32 . However, in some circumstances it may be desirable to size the straight, substantially rigid elongated body  157  so that it will extend out of the coronary sinus and into the right atrium.  
         [0084]    Furthermore, it should also be appreciated that the system provides a degree of tactile feedback to the user during deployment. More particularly, substantial resistance will typically be encountered as the straight, substantially rigid elongated body  157  is pushed out of right atrium  24  and into coronary sinus  30 ; then resistance will typically drop as body  157  is moved through the coronary sinus; and then resistance will typically increase significantly again as the distal tip of body  157  comes to the far end  31  of the coronary sinus. Thus, there is a sort of tactile “sweet spot” when the straight, substantially rigid elongated body  157  is located in the coronary sinus between coronary ostium  27  and AIV  32 , and this tactile “sweet spot” can be helpful to the user in positioning the straight, substantially rigid elongated body  157  in coronary sinus  30 .  
         [0085]    At this point the straight, substantially rigid elongated body  157  is locked in position, e.g., by closing adjustable valve  133 , and balloon  139  may be deflated.  
         [0086]    System  100  is left in this position until it is no longer needed. In some cases this may mean that system  100  is left in position for a period of a few hours, days or weeks; in other cases system  100  may be substantially permanent. If and when system  100  is to be removed, push rod  109  is removed from delivery catheter  106 , and then delivery catheter  106  is removed from the patient.  
         [0087]    Thus it will be seen that with the present invention, the straight, substantially rigid elongated body  157  is essentially force-fit into the normally curved portion of the coronary sinus adjacent to the mitral valve&#39;s posterior leaflet. By properly sizing the length of the straight, substantially rigid elongated body  157  relative to the natural curvature of the patient&#39;s anatomy, and by properly positioning the straight, substantially rigid elongated body  157  in the patient&#39;s coronary sinus, the straight, substantially rigid elongated body will cause at least a portion of the coronary sinus to assume a substantially straight configuration adjacent to the posterior leaflet of the mitral valve. This action will in turn drive the posterior annulus of the mitral valve anteriorly, so as to improve leaflet coaptation and thereby reduce mitral regurgitation. Thus, by inserting the straight, substantially rigid elongated body  157  into the coronary sinus adjacent to the posterior leaflet of the mitral valve, the annulus of the mitral valve is effectively manipulated so that it will assume an increased radius of curvature.  
         [0088]    It has also been found that by inserting the straight, substantially rigid elongated body into the coronary sinus adjacent to the posterior leaflet of the mitral valve, the left ventricle may also be remodeled so as to help alleviate congestive heart failure.  
         [0089]    It is significant to note that with the present invention, the distal and proximal ends of straight, substantially rigid elongated body  157  apply a posteriorly-directed force on the walls of coronary sinus  30  (e.g., as shown with arrows P in FIG. 7) while the intermediate portion of straight, substantially rigid elongated body  157  applies an anteriorly-directed force on the walls of coronary sinus  30  (e.g., as shown with arrows A in FIG. 7).  
         [0090]    In some cases the proximal end  130  of delivery catheter  106  may be fixed to the patient&#39;s outer skin using standard patient care methods such as adhesive tape, pursestring sutures, skin staples, etc. In other cases proximal end  130  of delivery catheter  106  may include a sewing cuff whereby the delivery catheter may be secured to the patient&#39;s tissue by suturing. See, for example, FIG. 8, where a sewing cuff  166  is shown attached to the proximal end  130  of delivery catheter  106 . If desired, an element  169  may be provided proximal to adjustable valve  133 , whereby flexible push rod  109  may be made fast to delivery catheter  106 . By way of example, element  169  may comprise a crimpable element to secure flexible push rod  109  to delivery catheter  106 , which is in turn secured to the patient. If desired, the proximal end of the assembly may be embedded under the skin of the patient, e.g., in the case of a permanent implant.  
         [0091]    As noted above, it can be helpful to anchor the distal end of delivery catheter  106  in position within the coronary sinus prior to pushing push rod  109  into the delivery catheter. Such an arrangement will keep the delivery catheter in place as the push rod makes the turn within the right atrium and enters the coronary sinus. In the absence of such anchoring, the push rod may drive the delivery catheter down the inferior vena cava  21 . By securing the distal end of delivery catheter  106  to the walls of coronary sinus  30 , the delivery catheter can be stabilized against diversion down the inferior vena cava  21  when the straight, substantially rigid elongate body  157  encounters initial resistance to making the turn into the coronary sinus.  
         [0092]    The balloon  139  is one way of accomplishing such anchoring. However, it is also possible to utilize other types of securing mechanisms to anchor the distal end  127  of delivery catheter  106  in position within coronary sinus  30 , e.g., spring clips, ribs, etc.  
         [0093]    Alternatively, and looking next at FIG. 9, the distal end  151  of push rod  109  may itself be provided with a distal anchor, e.g., such as the distal anchor  172  shown in FIG. 9.  
         [0094]    It is also possible to prevent diversion of delivery catheter  106  down inferior vena cava  21  without anchoring the distal end of delivery catheter  106  or flexible push rod  109  to the walls of the coronary sinus. More particularly, and looking now at FIG. 9A, there is shown a support catheter  173  which is formed out of a more rigid material than delivery catheter  106 . Support catheter  173  is constructed so that its distal end  174  can be positioned in coronary ostium  27  and then its sidewall  174 A can support delivery catheter  106  adjacent to inferior vena cava  21  when push rod  109  is passed down delivery catheter  106 , whereby to prevent delivery catheter  106  from diverting down inferior vena cava  106 . FIG. 9A also shows an introducer catheter  174 B at the entrance to jugular vein  18 .  
         [0095]    Looking next at FIG. 9B, there is shown a push rod  112 A which comprises an alternative form of push rod. Push rod  112 A comprises a flexible body  148 A having a distal end  151 A and a proximal end  154 A. Preferably flexible body  148 A is formed out of a superelastic shape memory alloy such as Nitinol. A straight, substantially rigid member  157 A is formed on body  148 A, proximal to distal end  151 A. Substantially rigid member  157 A can have a variety of different lengths so as to accommodate different patient anatomies. A tube  158 A is positioned concentrically over flexible body  148 A and extends for at least part of the distance between substantially rigid member  157 A and a locking collar  159 A secured to proximal end  154 A of flexible body  148 A. Tube  158 A serves as a stiffener or reinforcer for flexible body  148 A, whereby flexible body  148 A can have the flexibility required (particularly at its distal end) to traverse tortuous vascular passages, yet have the column strength (particularly at its proximal end) to advance flexible body  148 A by pushing. In addition, tube  158 A can be sized so as to have a diameter just slightly smaller than the internal diameter of delivery catheter  106 , whereby to further support flexible body  148 A. In one preferred form of the invention, tube  158 A preferably comprises a PEEK tube.  
         [0096]    Looking next at FIG. 9C, flexible body  148 A can also be necked down, e.g., as shown at  220 , so as to further increase the flexibility of flexible body  148 A distal to tube  158 A.  
         [0097]    Flexible push rod  112 A is preferably a device with a series of changes in stiffness and flexibility that allows the device to be bending flexible and column strength sufficient to pass through an arduous path, such as the vascular system, yet have specific areas of stiffness to reduce mitral valve regurgitation by pushing the posterior annulus anteriorly and thus closing the gap between the anterior and posterior leaflets of the mitral valve. One preferred embodiment of this device is a single rod of superelastic material, such as Nitinol, that has a plurality of changes in diameter that allows for bending flexibility. The largest diameter section has a bending stiffness sufficient to push the posterior annulus anteriorly. The longest portions of the rod have many serrations that provide bending flexibility along with column strength.  
         [0098]    Alternatively, and looking next at FIG. 9D, it is also possible to provide additional flexibility to flexible body  148 A by severing the flexible body along its length and then connecting the two severed portions with a flexible tube or wire, e.g., such as is shown at  225 .  
         [0099]    In addition to the foregoing, in an alternative embodiment as shown in FIG. 9E, it is also possible to use guiding catheter  162 , preferably with a pre-formed tip  164 , which could be advanced over guidewire  103  whereby preformed tip  164  of guiding catheter  162  would engage the opening of the coronary sinus vessel. This tip  164  is sufficiently flexible to execute extreme bends, and may be of reduced diameter. Upon successful engagement and advancement of the guiding catheter tip  164  a short distance into the coronary sinus, guidewire  103  is removed. Then delivery catheter  106  is advanced toward and into the coronary sinus through the center lumen  165  of guiding catheter  162 . Then, push rod  109  would be advanced within center lumen  136  of the delivery catheter into the coronary sinus and into position as described herein.  
         [0100]    It is also envisioned that the structure of guiding catheter  162  would be added onto delivery catheter  106  to enable the placement of the distal tip of delivery catheter  106  into the coronary sinus and enable the delivery of push rod  109 , thereby combining the function of the two catheters into one catheter with only the center lumen  136  within the combined guide and delivery catheter  106  and a closed distal tip (i.e. single lumen catheter).  
         [0101]    As noted above, as push rod  109  or  112 A is advanced to the region adjacent to the posterior annulus of the mitral valve, the straight, substantially rigid elongated body  157  or  157 A will distort the natural configuration of the coronary sinus so that it will assume a substantially straight configuration. While this action induces the desired valve remodeling, it can also induce a significant stress on the walls of the coronary sinus, particularly at the distal and proximal ends of the straight, substantially rigid elongated body  157  or  157 A, where stress will be concentrated. To this end, the construction of the straight, substantially rigid elongated body  157  or  157 A may be modified somewhat so as to better distribute this stress. More particularly, and looking next at FIG. 10, the distal and proximal ends of straight, substantially rigid elongated body  157  may include relatively flexible portions  175  to help better distribute the stress exerted on the walls of the coronary sinus. Additionally, and/or alternatively, any taper applied to the distal and proximal ends of straight, substantially rigid elongated body  157  may be elongated, e.g., such as shown at  178  in FIG. 11, so as to better distribute the stress imposed on the walls of the coronary sinus.  
         [0102]    In the preceding discussion of system  100 , push rod  109  is described as being inserted to the surgical site through the insertion cannula  106  and remaining within insertion cannula  106  while at the surgical site and, when push rod  109  is to be removed, removing push rod  109  and then surgical cannula  106 . However, if desired, once push rod  109  has been deployed at the surgical site, insertion cannula  106  may then be removed, leaving just push rod  109  at the surgical site. See, for example, FIG. 11A.  
         [0103]    It is also possible to advance push rod  109  directly to the surgical site without passing it through an insertion cannula; in this case push rod  109  would be advanced on its own through the intervening vascular structure until it is deployed in coronary sinus  30 .  
         [0104]    Looking next at FIG. 12, there is shown a system  181  which comprises another preferred embodiment of the present invention. More particularly, system  181  generally comprises the guidewire  103 , a straight, substantially rigid elongated body  184  and a push cannula  187 .  
         [0105]    Guidewire  103  is as previously described.  
         [0106]    Straight, substantially rigid elongated body  184 , which may have a variety of different lengths, comprises a distal end  188  and a proximal end  190 . A central lumen  193  extends between distal end  188  and proximal end  190 . Central lumen  193  accommodates guidewire  103 .  
         [0107]    Push cannula  187  comprises a distal end  194  and a proximal end  196 . A central lumen  199  extends between distal end  194  and proximal end  196 . Central lumen  199  accommodates guidewire  103 .  
         [0108]    As a result of this construction, elongated body  184  and push cannula  187  may be mounted on guidewire  103 , and push cannula  187  may be used to push elongated body  184  down guidewire  103 . See FIG. 13.  
         [0109]    System  181  may be used as follows to reduce mitral regurgitation.  
         [0110]    First, distal end  115  of guidewire  103  is passed down jugular vein  18  (or the left subclavian vein  15 ) of a patient, down superior vena cava  9 , through right atrium  24  of the heart, and into coronary sinus  30  (FIG. 14). It will be appreciated that as flexible guidewire  103  is passed down coronary sinus  30 , the guidewire will tend to assume the natural curved shape of the coronary sinus, due to the flexible nature of the guidewire. The guidewire&#39;s atraumatic spring tip  121  will help minimize damage to vascular structures as the guidewire is advanced into position.  
         [0111]    Next, distal end  188  of straight, substantially rigid elongated body  184  is placed over proximal end  118  of guidewire  103  and passed a short distance down the guidewire. Then the distal end  194  of push cannula  187  is placed over proximal end  118  of guidewire  103 , and then push cannula  187  is advanced down the guidewire. As push cannula  187  is advanced down the guidewire, its distal end  194  pushes the straight, substantially rigid elongated body  184  ahead of it. See FIG. 15.  
         [0112]    As the straight, substantially rigid elongated body  184  is passed down the coronary sinus, it will force the coronary sinus to assume a straight configuration at the point where the straight, substantially rigid elongated body  184  currently resides. Push cannula  187  is pushed down guidewire as needed, until the straight, substantially rigid elongated body  184  is located adjacent to the posterior annulus of the mitral valve. See FIG. 16. As this occurs, the presence of the straight, substantially rigid elongated body  184  in the coronary sinus will cause coronary sinus to assume a substantially straight configuration at this point, so that the posterior annulus of the mitral valve is forced anteriorly. This will cause the posterior mitral valve leaflet to also move anteriorly so as to improve leaflet coaptation and thereby reduce (or completely eliminate) mitral valve regurgitation. Using standard visualization means (e.g. echocardiography or fluoroscopy), the exact position of the straight, substantially rigid elongated body may be adjusted so as to reduce (or completely eliminate) regurgitation in the mitral valve.  
         [0113]    If desired, the push cannula  187  may be provided with a releasably attachable interface (e.g., a grasper) so that it may releasably secure the proximal end  190  of the straight, substantially rigid elongated body  184 . Such a feature will permit the straight, substantially rigid elongated body to be pulled backward within the coronary sinus, either for positioning or removal purposes.  
         [0114]    Where elongated body  184  is to be left within the body for a substantial period of time, it is possible to leave the apparatus in the position shown in FIG. 16, i.e., with elongated body  184  fit over guidewire  103  and at the end of push cannula  187 . Alternatively, guidewire  103  and/or push cannula  187  may be removed, leaving just elongated body  184  deployed at the surgical site (FIG. 16A). To the extent that elongated body  184  may be left by itself at the surgical site, it may be desirable to provide elongated body  184  with an eyelet or hook or other graspable feature G (FIG. 16B) such that a retriever R may thereafter be used to easily grapple and extract the elongated body  184  from the surgical site.  
         [0115]    Elongated body  157  and/or elongated body  184  may have any of a variety of non-straight shapes along its length. For example, the elongated body may be wavy, spiraled, or curved along all or a portion of its length. By way of example, elongated body  157  and/or  184  may have a curved configuration so as to invert the natural curvature of the coronary sinus, i.e., so that it is bowed towards the anterior annulus. Or the elongated body may have a compound shape along its length, e.g., it may have a sort of “w” shape, with the center of the “w” being directed towards the anterior annulus. See, for example, FIG. 17, which shows a push rod  109  having an elongated body  157  with a “w” type of shape; and see FIG. 18, which shows an elongated body  184  with a “w” type of shape. See also FIGS. 19 and 20, which show a “w” shaped elongated body  184  being advanced down guidewire  103  (FIG. 19) to a position adjacent to mitral valve  36  (FIG. 20), whereby to reduce mitral regurgitation. Any of the aforementioned elongated body shapes, or other alternative shapes, may effect the anterior displacement of the posterior annulus that results in reduction of the mitral valve regurgitation.  
         [0116]    It is preferable that use of the present invention not result in occlusion of coronary sinus  30 . Thus, with system  100  shown in FIG. 3, delivery catheter  106  is preferably sized so as to have a diameter less than the diameter of coronary sinus  30 , so that blood may flow about the perimeter of delivery catheter  106  when delivery catheter  106  is disposed in coronary sinus  30 . Alternatively, and/or additionally, and looking now at FIGS. 21 and 22, delivery catheter  106  may be provided with one or more longitudinally-extending surface grooves SG so as to facilitate blood flow past the perimeter of delivery catheter  106 . Similarly, with system  181  shown in FIG. 12, elongated body  184  is preferably sized so as to have a diameter less that the diameter of coronary sinus  30 , so that blood may flow about the perimeter of elongated body  184  when elongated body  184  is disposed in coronary sinus  30 . Alternatively, and/or additionally, and looking now at FIGS. 23 and 24, elongated body  184  may be provided with one or more longitudinally-extending surface grooves SG so as to facilitate blood flow past the perimeter of elongated body  184 .  
         [0117]    In system  100  (FIG. 3) and in system  181  (FIG. 12), the elongated bodies  157  and  184  are shown completely formed prior to their deployment in the patient. However, it is also possible to form elongated body  157  and/or elongated body  184  in situ from a plurality of smaller elements.  
         [0118]    Thus, for example, in FIGS.  25 - 27  there is shown an alternative form of push rod  109  for use with guidewire  103  and delivery catheter  106 . More particularly, push rod  109  comprises flexible body  148  and a plurality of substantially rigid elongated elements  157 A,  157 B,  157 C, etc. which collectively form the complete elongated body  157 . Preferably the distalmost elongated element  157 A is fixed to flexible body  148  while the remaining elongated elements  157 B,  157 C,  157 D, etc. are free to slide on flexible body  148 . In addition, elongated elements  157 A,  157 B,  157 C, etc. preferably include connectors C for permitting one elongated element to be secured to a neighboring elongated body. The connectors C shown in FIG. 25 comprise male and female screw type connectors; however, other types of connectors may also be used.  
         [0119]    By assembling the elongated body  157  in situ using a plurality of elongated elements  157 A,  157 B,  157 C, etc., it is possible to create an elongated body  157  which is perfectly sized to the needs of the patient.  
         [0120]    The push rod  109  shown in FIGS.  25 - 27  may be used as follows. First, guidewire  103  is passed down to the coronary sinus (FIG. 28). Then delivery catheter  106  is passed down guidewire  103  and into the coronary sinus (FIGS. 28 and 29). Then the guidewire  103  is withdrawn from the surgical site and replaced by the push rod&#39;s flexible body  148  with elongated element  157 A attached (FIG. 30). Next, a plurality of elongated elements  157 B,  157 C,  157 D, etc. are slid down flexible body  148  (FIG. 31) and secured to elongated element  157 A (and any preceding elongated element). As many elongated elements  157 A,  157 B,  157 C, etc. are used as is necessary to effect the desired leaflet coaptation (FIG. 32).  
         [0121]    In FIGS.  32 A- 32 C, there is shown another form of push rod  109 . More particularly, with this form of the push rod, elongated body  157  is formed by a plurality of elongated elements  157 A,  157 B,  157 C, etc. which collectively form the complete elongated body  157 . Preferably the distalmost elongated element  157 A is fixed to flexible body  148  while the remaining elongated elements  157 A,  157 B,  157 C, etc. are free to slide on flexible body  148 . With this version of the invention, elongated body  157  may be formed in situ by moving elongated elements  157 A,  157 B,  157 C, etc. distally, with distalmost elongated element  157 A acting as a distal stop, and then keeping elongated elements  157 A,  157 B,  157 C, etc. biased distally with a holding mechanism, e.g., a crimp CR.  
         [0122]    In FIGS.  25 - 32 , and in FIGS.  32 A- 32 C, elongated elements  157 A,  157 B,  157 C, etc. are shown configured so as to form a substantially straight elongated body  157 . However, if desired, elongated elements  157 A,  157 B,  157 C, etc. could have alternative configurations so as to form other body shapes. Thus, for example, in FIG. 32D elongated elements  157 A,  157 B,  157 C, etc. are shown forming a curved elongated body  157 , and in FIG. 32E elongated elements  157 A,  157 B,  157 C, etc. are shown forming a composite curved-and-straight elongated body  157 . It will be appreciated that still other shapes may be formed by elongated elements  157 A,  157 B,  157 C, etc. In this respect, it will be appreciated that the shapes of elongated body  157  may be established either by (1) forming elongated elements  157 A,  157 B,  157 C, etc. so that they have only one possible way of being assembled together, or (2) by forming elongated elements  157 A,  157 B,  157 C, etc. so that they have multiple ways of being assembled together. In this latter situation, one possible way to vary the final configuration of elongated body  157  is by individually rotating various ones of elongated elements  157 A,  157 B,  157 C, etc., e.g., such as is shown in FIGS. 32D and 32E.  
         [0123]    As noted above, it is also possible to form the elongated body  184  of system  181  (FIG. 12) in situ from a plurality of smaller elements.  
         [0124]    Thus, for example, in FIGS. 33 and 34 there is shown an alternative form of elongated body  184  which comprises a plurality of substantially rigid elongated elements  184 A,  184 B,  184 C, etc. which collectively form the complete elongated body  184 . In addition, elongated elements  184 A,  184 B,  184 C, etc. preferably include connectors C for permitting one elongated element to be secured to a neighboring elongated element. The connectors C shown in FIG. 25 comprise male and female screw type connectors; however, other types of connectors may also be used.  
         [0125]    By assembling the elongated body  184  in situ using a plurality of elongated elements  184 A,  184 B,  184 C, etc., it is possible to create an elongated body  184  which is perfectly sized to the needs of the patient.  
         [0126]    The elongated body  184  shown in FIGS. 33 and 34 may be used as follows. First, guidewire  103  is passed down coronary sinus  30  (FIG. 35). Then push cannula  187  is used to push a plurality of elongated elements  184 A,  184 B,  184 C, etc. down guidewire  103  and into the coronary sinus (FIGS. 36 and 37). As many elongated elements  184 A,  184 B,  184 C, etc. are used as is necessary to effect the desired leaflet coaptation (FIG. 37).  
         [0127]    In FIGS.  37 A- 37 C, there is shown another form of elongated body  184 . More particularly, with this form of elongated body, the elongated body  184  is formed by a plurality of elongated elements  184 A,  184 B,  184 C, etc. which collectively form the complete elongated body  184 . Preferably, all of the elongated elements  184 A,  184 B,  184 C, etc. are free to slide on guidewire  103 . With this version of the invention, elongated body  184  may be formed in situ by moving elongated elements  184 A,  184 B,  184 C, etc. distally and then drawing them tightly together, e.g., such as by using a cinching system such as that shown in FIG. 37C and comprising a distal member DM and a crimp CR.  
         [0128]    Again, in FIGS.  33 - 37 , and in FIGS.  37 A- 37 C, elongated element  184 A,  184 B,  184 C, etc. are shown configured so as to form a substantially straight elongated body  184 . However, if desired, elongated elements  184 A,  184 B,  184 C, etc. could have alternative configurations so as to form other body shapes. Thus, for example, in FIG. 37D elongated elements  184 A,  184 B,  184 C, etc. are shown forming a curved elongated body  184 , and in FIG. 37E elongated elements  184 A,  184 B,  184 C, etc. are shown forming a composite curved-and-straight elongated body  184 . It will be appreciated that still other shapes may be formed by elongated elements  184 A,  184 B,  184 C, etc. In this respect it will be appreciated that the shapes of elongated body  184  may be established either by (1) forming elongated elements  184 A,  184 B,  184 C, etc. so that they have only one possible way of being assembled together, or (2) by forming elongated elements  184 A,  184 B,  184 C, etc. so that they have multiple ways of being assembled together. In this latter situation, one possible way to vary the final configuration of elongated body  184  is by individually rotating various ones of elongated elements  184 A,  184 B,  184 C, etc., e.g., such as is shown in FIGS. 37D and 37E.  
         [0129]    Looking next at FIGS.  37 F- 37 I, there is shown another form of push rod  109  having an elongated body  157  formed by a plurality of elongated elements  157 A,  157 B,  157 C, etc. Each of the elongated elements  157 A,  157 B,  157 C, etc. is attached to flexible body  148  and is separated from adjacent elongated elements by a gap G. By orienting gaps G radially away from mitral valve  36  (FIG. 37H), push rod  109  will be able to curve as required so as to follow the natural curvature of the coronary sinus, e.g., during insertion of push rod  109  into coronary sinus  30 . However, by rotating flexible body  148  about its axis so that gaps G are oriented  180  degrees opposite to that shown in FIG. 37H (i.e., as shown in FIG. 37I), gaps G will be closed and push rod  109  will be straightened, whereby to apply an anteriorly-directed force to the posterior annulus of mitral valve  36  and reduce mitral regurgitation.  
         [0130]    Looking next at FIGS. 37J and 37K, there is shown another form of the invention. In this construction, an internal member IM has a plurality of slots SI and an external member EM has a plurality of slots SE. Internal-member IM is concentrically received within external member EM. By orienting internal member IM and external member EM so that slots SI are aligned with slots SE (FIG. 37J), internal member IM and external member EM may be curved as required so as to follow the natural curvature of the coronary sinus, e.g. during insertion of the members into the coronary sinus. However, by orienting internal member IM and external member EM so that slots SI are oriented away from slots SE (FIG. 37K), internal member IM and external member EM will be straightened, whereby to apply an anteriorly-directed force to the posterior annulus of the mitral valve and reduce mitral regurgitation.  
         [0131]    It is also possible to form elongated body  157  of push rod  109  (FIG. 3) with an inflatable construction. More particularly, and looking next at FIG. 38, there is shown a push rod  109  having an inflatable elongated body  157  in the form of a balloon B. The push rod&#39;s flexible body  148  includes an inflation lumen L which communicates with the interior of balloon B, whereby fluid may be supplied to the interior of the balloon so as to inflate the balloon. The balloon B is constructed so that it has a flexible configuration when it is in a deflated condition and an elongated, straight configuration when it is in an inflated condition.  
         [0132]    The push rod  109  of FIG. 38 may be used as follows. First, guidewire  103  is advanced into the coronary sinus  30  (FIG. 4). Then delivery cannula  106  is advanced over guidewire  103  until the distal end of the delivery cannula is in coronary sinus  30  (FIG. 5). Next, guidewire  103  is withdrawn (FIG. 6). Then push rod  109 , with elongated body  157  in a deflated condition, is advanced along the interior of delivery cannula  106  so that balloon B is adjacent to the mitral valve (FIG. 39). Then balloon B is inflated, using inflation lumen L, so that elongated body assumes its elongated, straightening configuration (FIG. 40). As this occurs, the posterior annulus of the mitral valve is compressed anteriorly, so as to reduce mitral regurgitation.  
         [0133]    It is also possible to form an inflatable elongated body  157  of push rod  109  with other configurations. By way of example, it is possible to form an inflatable body  157  with a piston-type configuration, whereby the body may be elongated or shortened as desired. More particularly, and looking now at FIGS. 41 and 42, inflatable body  157  may comprise a distal portion  157 ′ and a proximal portion  157 ″, with the distal and proximal portions being in a sliding, piston-like relationship. As a result, fluid may be supplied to the combined interiors of the distal and proximal portions, so as to force the two elements apart relative to one another. In use, the push rod  109  of FIGS. 41 and 42 is positioned in its “compressed” state (FIG. 41), passed down the interior of delivery cannula  106  until inflatable elongated body  157  is positioned adjacent to the mitral valve, and then inflated (using inflation lumen L) into its “expanded” state (FIG. 42). As this occurs, the naturally curved coronary sinus is straightened, thereby pushing the posterior annulus of the mitral valve anteriorly, whereby to reduce mitral regurgitation.  
         [0134]    In addition to the foregoing, it should also be appreciated that with respect to push rod  109 , the flexible body  148  may comprise an electrical lead for an implantable bi-ventricular pacing device and/or an electrical lead for an implantable cardio defibrillator device, etc. In this case, the distal end of flexible body  148  would be elongated somewhat and would not reside within the coronary sinus; rather, it would be positioned within the tissue which is to receive the electrical stimulus while elongated body  157  is positioned adjacent to the mitral valve. Such a construction would allow the bi-ventricular pacing device and/or the implantable cardio defibrillator device to work in conjunction with elongated body  157  to reduce mitral regurgitation.  
         [0135]    It should also be appreciated that the function of hydraulic energy employed to enlarge inflatable body  157  may be substituted by a mechanical energy transformer such as a lead screw mechanism or an electromechanical solenoid.  
         [0136]    In a corresponding fashion, the guidewire  103  over which elongated body  184  is deployed may also be in the form of an electrical lead for an implantable bi-ventricular pacing device and/or an electrical lead for an implantable cardio defibrillator device, etc. Again, in this case the distal end of the wire will be positioned within the tissue which is to receive the electrical stimulus while elongated body  184  is positioned adjacent to the mitral valve. Such a construction would allow the implantable bi-ventricular pacing device and/or the implantable cardio defibrillator device to work in conjunction with elongated body  157  to reduce mitral regurgitation.  
         [0137]    Looking next at FIGS. 43 and 44, there is shown yet another form of the present invention. In this form of the invention, there is provided an elongated shape memory alloy body SMA which is configured to be substantially flexible at a temperature T 1 , and substantially rigid and in a straight configuration at another temperature T 2 , where temperature T 2  is normal body temperature. In this situation, body SMA is brought to temperature T 1 , so that it may be inserted more easily into the natural curvature of the coronary sinus, e.g., during insertion of body SMA into the coronary sinus (FIG. 43). However, when body SMA thereafter transitions to temperature T 2 , body SMA will assume its straight configuration (FIG. 44), whereby to apply an anteriorly-directed force to the posterior annulus of the mitral valve and reduce mitral regurgitation. It will be appreciated that the configuration of body SMA may be other than straight (i.e., “w” shape, etc.) to best displace the posterior annulus anteriorly.  
         [0138]    In other alternative embodiments, the elongated body may be flexible along at least a portion of its length. Regional flexibility and regional stiffness may allow for straightening of select locations of the coronary sinus and corresponding locations of the posterior mitral annulus. This can cause regions of the mitral annulus to move anteriorly, thus causing regional improvements in leaflet coaptation. In addition, the elongated body may be formed by two end segments connected together by a filament: by anchoring the two end segments relative to the anatomy and pulling the filament taught, the naturally curved wall of the coronary sinus can be straightened, whereby to move the posterior mitral annulus anteriorly and thereby reduce mitral regurgitation.  
         [0139]    It should also be appreciated that the present invention may also be used to alter the shape of other cardiac tissues, including but not limited to the left ventricle, for other uses, including the treatment of cardiac dysfunction.  
         [0140]    It is to be understood that the present invention is by no means limited to the particular constructions herein disclosed and/or shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.