BACKGROUND: There are conflicting data about gender differences in short-term mortality after acute myocardial infarction (AMI) after adjust*ing for age and other prognostic factors. Therefore, we investigated the risk profile, clinical presentation, in-hospital mortality and mechanisms of death in women and men after the first AMI. METHODS: The data were obtained from a chart review of 3382 consec*utive patients, 1184 (35%) women (69.7±10.9 years) and 2198 (65%) men (63.5±11.8 years) with a first AMI. The effect of gender and its interaction with age, risk factors and thrombolytic therapy on overall mortality and mechanisms of death were examined using logistic regression. RESULTS: Unadjusted in-hospital mortality was higher in women (OR 1.77, 95% CI 1.47-2.15). Adjustment that included both age only and age and other base-line differences (hypertension, diabetes mellitus, hy*percholesterolemia, smoking, AMI type, AMI site, mean peak CK value, thrombolytic therapy) decreased the magnitude of the relative risk of women to men but did not eliminate it (OR 1.26, 95% CI 1.03-1.54 and OR 1.31 95% CI 1.03-1.66, respectively). Multivariate analysis revealed that female gender was an independent predictor of in-hospital mortal*ity after the first AMI. Women were dying more often because of me*chanical complications--refractory pulmonary edema and cardiogenic shock (P=0.02) or electromechanical dissociation (P=0.03), and men were dying mostly by arrhythmic death, primary ventricular tachycar*dia/fibrillation (P=0.002). Female gender was independently associated with mechanical death (OR 1.56, 95% CI 1.35-2.58; P=0.01) and anterior AMI was independently associated with arrhythmic death (OR 0.54, 95% CI 0.34-0.86; P=0.01). CONCLUSION: Our results demonstrate significant differences in mech*anisms of in-hospital death after the first AMI in women and men, sug*gesting the possibility that higher in-hospital mortality in women exists primarily because of the postponing AMI death due to the gender-re*lated differences in susceptibility to cardiac arrhythmias following acute coronary events.