Background: Myocardial infarction (MI) in the absence of electrocardiographic ST-segment elevation or new bundle branch block is the cause of hospitalization for a large and steadily increasing proportion of patients with acute ischemic chest pain. Despite its prevalence, the common demographic features, current hospital-based management, and short-term clinical outcome among patients with non-ST-segment elevation MI remain poorly defined. Methods: A total of 183113 patients with non-ST-segment elevation MI were identified in the National Registry of Myocardial Infarction database. Using a validated model, 43 928 patients (24.0%) were retrospectively placed in major, 34917 (19.1%) in intermediate, and 104 268 (56.9%) in minor severity clinical event categories that included hospital death, recurrent myocardial ischemia, and nonfatal recurrent MI. Results: The administration of widely available and universally recommended pharmacologic therapies, including aspirin and beta -adrenergic blocking agents, was suboptimal, particularly among patients with major severity clinical events. In contrast, coronary angiography and mechanical revascularization procedures were commonplace (>60% of all patients) and most frequently performed in patients within the minor (compared with the major) severity clinical event category (58.2% and 42.7%, respectively). Conclusions: Patients with non-ST-segment elevation MI are a heterogeneous population, with readily identifiable demographic characteristics and clinical features associated with important early outcomes, including death. Nationwide efforts directed toward maximizing pharmacologic therapy utilization and the performance of invasive procedures according to established guidelines must continue.
