To investigate geometrical and functional changes involving the left ventricle (LV) and mitral valve (MV) apparatus in patients with depressed LV ejection fraction (LVEF) and ischemic MV regurgitation (IMVR). A series of patients with three vessels coronary artery disease (CAD) and depressed LVEF underwent cardiac magnetic resonance imaging to investigate MV/LV geometry and function, and myocardial perfusion/vitality. Geometrical data were indexed by anterior MV leaflet length. Two groups were identified: CAD without IMVR (group CAD), and with IMVR (group IMV). Eleven patients were enrolled in the CAD group and 13 in the IMV group. IMVR volume was significantly higher in the IMV group (24.0+/-12.0 vs 4.5+/-5.2; p<0.0001). LVEF% was comparable (IMV 34.6+/-13.0 vs CAD 31.5+/-13.0; p=ns). Indexed MV/LV geometrical variables were comparable in the two groups. Perfusion/vitality study showed inferior myocardial necrosis occurred more often in the IMV group (p=0.01). At Pearson test, MV regurgitation occurrence correlated with inferior myocardial necrosis (r=0.5; p=0.006), non-indexed systolic/diastolic annular inter-commissural diameters (r=0.4; p=0.04) and MV annular areas (r=0.4; p=0.04). Papillary muscles distance (PMD) and LV volumes inversely correlated with LVEF% (r=-0.6; p<0.05 and r=-0.8; p<0.001). At multivariable analysis, no independent determinants for IMVR were identified and LV volumes were the sole determinants for LVEF% (p<0.05). In patients with depressed LVEF%, IMV cannot be explained by LV geometrical modifications alone. Although PMD, LV volumes, and LVEF% are correlated, they have no direct impact in the development of IMVR. In contrast, inferior myocardial necrosis and increased inter-commissural MV diameters may lead to deformity of MV complex and subsequent IMV.