Background: Treatment of heart failure by surgical procedures such as mitral annuloplasty and left ventricular (LV) restoration is increasingly applied to patients with ischemic mitral regurgitation (IMR) and LV dysfunction. The clinical efficacy of delayed enhancement magnetic resonance imaging (DE-MRI) was studied to predict LV functional recovery and adverse outcomes after these therapies. Methods and Results: In 26 patients with IMR and a LV ejection fraction <40%, DE-MRI was performed before the operation and the percentage of regional myocardial scarring was quantified at the basal, mid, and apical LV. Calculated percentage of fibrosis was 12±12% at the base, 24±15% at the mid, and 35±31% at the apical LV. The degree of basal fibrosis was a significant predictor of less improvement of LV ejection fraction and postoperative restrictive diastolic filling. A linear correlation was noted between basal fibrosis and postoperative ejection fraction (P=0.001, R=-0.61), the early to late mitral valve flow ratio (P=0.0005, R=0.66), and deceleration time (P=0.01, R=-0.51). Logistic regression analysis demonstrated that the percentage of basal fibrosis was the independent predictor of postoperative adverse clinical outcomes (odds ratio, 1.26; P=0.04). Conclusions: In patients undergoing surgical heart failure therapy for IMR, the extent of basal fibrosis characterized by DE-MRI might be a useful predictor of postoperative LV systolic and diastolic functional recovery and postoperative adverse outcomes. (Circ J 2011; 75: 148-156)