Background-Microvascular obstruction (MO) is associated with large acute myocardial infarction and lower left ventricular (LV) ejection fraction and predicts greater remodeling, but whether this effect is abolished by contemporary antiremodeling therapies is subject to debate. We examined the influence of several infarct characteristics, including MO, on LV remodeling in an optimally treated post-acute myocardial infarction cohort, using contrast-enhanced cardiac magnetic resonance. Methods and Results-One hundred patients (mean age, 58.9Ϯ12 years, 77% men) underwent contrast-enhanced cardiac magnetic resonance at baseline (Ϸ4 days) and at 12 and 24 weeks. The effects on LV remodeling (ie, change in LV end-systolic volume index [⌬LVESVi]) of infarct site, transmurality, endocardial extent, and the presence of early and late MO were analyzed. Mean baseline infarct volume index decreased from 34.0 (21.2) mL/m 2 to 20.9 (12.9) mL/m