Post-infarction ventricular remodeling producing ischemic cardiomyopathy, ventricular aneurysms, and chronic ischemic mitral regurgitation is the most common cause of chronic congestive heart failure, a condition affecting approximately 4.6 million Americans. The rational of this proposal is to specifically examine surgical methods to positively affect the ventricular remodeling associated with posterior myocardial infarctions that produce delayed mitral regurgitation. Previous work in our laboratory suggest that ischemic mitral regurgitation in the post-infarction ventricle results from both dilatation of the mitral valve annulus and changes in its relationship to the papillary muscles. In this proposal, we will focus on potential surgical therapies inducting delayed coronary reperfusion, prophylactic standard mitral annuloplasty ring placement, restrictive mesh placed on the ventricle to prevent dilatation, and the placement of a novel saddle shaped mitral valve annuloplasty ring. Our hypothesis is that these interventions may prevent the development of congestive heart failure secondary to delayed mitral insufficiency. If our hypothesis is correct, these interventions would be directly beneficial to the subset of patients who initially present after a posterior myocardial infarction with intact ventricular function and little or no mural regurgitation, but later develop congestive heart failure secondary to chronic ischemic mitral regurgitation. The proposal utilizes an ovine model of ischemic mural regurgitation. At the time of infarction, sonomicrometry crystals will be placed on the ventricular epicardium allowing for precise analysis of three dimensional ventricular remodeling. Following the interventions mentioned above, serial hemodynamic measurements, echocardiographic imaging, and sonomicrometry data are obtained during the 12 weeks following infarction. These data will be examined to determine if the interventions being studied prevent the development of ischemic mitral regurgitation and diminished ventricular function.