BACKGROUND Coronary artery disease is the leading cause of death in women. We sought to validate previous clinical experience in which we have observed that elderly women with a very high left ventricular ejection fraction (LVEF) are at increased risk of death compared with elderly women with acute coronary syndromes with a normal LVEF. METHODS Data from 5,127 elderly female patients (age >65 years) enrolled in the Global Registry of Acute Coronary Events were collected. Patients were divided into 3 groups based on their LVEF: group I had a low ejection fraction (<55%), group II had a normal ejection fraction (55%-65%), and group III had a high ejection fraction (>65%). χ² test and multiple logistic regression analysis were performed. The main outcome measures were death in-hospital and death, stroke, rehospitalization, and myocardial infarction at 6-month follow-up. RESULTS Hospital mortality was 12% in group I. Patients in group III were more likely to die in-hospital than those in group II (P = .003). Multivariable logistic regression showed that high ejection fraction was an independent predictor of hospital death (odds ratio [OR] 2.5, 95% CI [CI] 1.2-5.2, P = .01), 6-month death (OR 2.0, 95% CI 1.1-3.4, P = .01), and cardiac arrest/ventricular fibrillation (OR 2.5, 95% CI 1.2-5.0, P = .01) compared with the normal ejection fraction group. CONCLUSIONS Having a very high LVEF (> 65%) is associated with worse survival and higher rates of sudden cardiac death than an LVEF considered to be in the reference range.