Specific Aim 1: This study will define the mechanism of functional MR in ischemic cardiomyopathy. Null Hypothesis: There is no difference in measurements of the mitral valve apparatus known to be associated with functional MR in ischemic cardiomyopathy among patients with different degrees of functional MR. To test this hypothesis, this study will compare measurements of annulus size and leaflet tethering in three groups of patients, those without MR, those with mild MR (effective regurgitant orifice area [EROA] less than 0.2 cm²), and those with at least moderate MR (EROA less than 0.2 cm²). The six specific measurements of MR mechanism include the following: 1) diastolic mitral annulus area; 2) percent of systolic annular contraction; 3) leaflet tenting area; 4) papillary muscle tethering distance; 5) papillary muscle separation distance; and 6) the primary chordal separation angle.