Background: Most patients with coronary artery disease (CAD) die of sudden cardiac death (SCD) or congestive heart failure. Left ventricular ejection fraction (LVEF) has its limitation as risk stratifier for SCD. Implantable cardioverter-defibrillator (ICD) is an important therapeutic modality for primary and secondary prevention of mortality in post-infarction patients with severe left ventricular (LV) dysfunction. Better risk stratification tools are needed to identify the best candidates for ICD implantation. Infarct characterization by cardiac magnetic resonance (CMR) has become an evolving potential tool for risk stratification.Objective: We sought to assess scar characteristics by late gadolinium enhancement CMR (LGE-CMR) in patients with post-infarction LV dysfunction and history of spontaneous sustained monomorphic ventricular tachycardia (SMVT) and compare them with control group subjected to electrophysiological study (EPS).Methods: Forty-eight patients with post-infarction LV dysfunction underwent CMR study. Twenty-four patients had history of SMVT and the other 24 were control group and underwent EPS to assess SMVT induciblity. Various scar characteristics were assessed in the spontaneous SMVT group and were compared with the inducible and non-inducible VT groups.Results: All patients had LGE in CMR indicating prior myocardial infarction (MI). Out of the 24 patients in the control group, six had inducible SMVT. In univariate analysis, total scar, absolute and as percent of LV, scar core, absolute, and as percent of LV, peri-infarct zone, absolute and as percent of LV, mean infarct transmurality and number of segments with LGE were statistically significant predictors of spontaneous SMVT experience and SMVT inducibilty by PES. In multivariate analysis total infarct as percent of LV was the only significant independent predictor of spontaneous SMVT experience (OR 1.33 per % change, 95% CI 1.12-1.6, p = 0.001) and SMVT inducibility (OR 1.3 per % change, 95% CI 1.1-1.6, p = 0.004). Peri-infarct zone as percent of LV became statistically non-significant predictor for spontaneous SMVT (OR 0.86 per % change, 95% CI 0.6-1.35, p = 0.5) and SMVT inducibility (OR 0.8 per % change, 95% CI 0.4-1.4, p = 0.42). Conclusion: Characterization of myocardial infarct by LGE-CMR specifically total infarct size isbetter predictor of spontaneous SMVT experience and SMVT inducibility than LVEF. Thishighlights the potential importance of myocardial scarring assessment in risk stratification ofpatients with ischemic cardiomyopathy for selection of patients who will benefit from ICDs.