The five studies included. STUDY I: Were women's emergency department (ED) presentations of ACI different from men's? STUDY II: Were there differences between women and men in the ED diagnosis and triage of patients with chest pain and other symptoms suggestive of ACI? STUDY III: Were there differences between women and men in the use of non-invasive and invasive treatments among patients presenting to the ED with ACI? STUDY IV: Were there significant differences between women and men in medical outcomes during the acute event and within 30 days following ED presentation with ACI? STUDY V: Had differences between women and men in their ED presentation, diagnosis, and/or triage for chest pain or other symptoms compatible with ACI changed over the past 10-15 years? In studying the impact of gender, these studies also included analyses for primary and interaction effects related to patient sociodemographic features, ED presenting clinical features, physician type and training, hospital type and ED setting, health insurance type, and include adjustments for patients' probabilities of having ACI as well as their likelihood of acute cardiac mortality.