- Background: In the emergency department the physician is often confronted with the decision of where to hospitalize a patient presenting with chest pain and a possible acute myocardial infarction - in the cardiac care unit or in the internal medicine ward. Objective: To characterize the clinical factors involved in the triage disposition of patients hospitalized with AMI in Israel to either CCUs or IMWs and to determine to what extent the perceived probability of ischemia influenced the disposition decision. Methods: During a 2 month nationwide prospective survey in the 26 CCUs and 82 of the 94 IMWs in Israel, we reviewed the charts of 1,648 patients with a discharge diagnosis of AMI. The probability of ischemia at admission was determined retrospectively by the Acute Coronary Ischemia Time-Insensitive Predictive Instrument. Co-morbidity was coded using the Index of Coexistent Diseases. Results: The ACI-TIPI score for patients admitted to CCUs or to IMWs was 76.2% and 57.7% respectively (P < 0.001). Multivariate analysis showed that young patients with a high probability of ischemia and low co-morbidity or functional impairment were more likely to be hospitalized in CCUs than in IMWs. Conclusion: In Israel, the factors that strongly influence the initial triage disposition of AMI patients to CCUs or IMWs are age, perceived probability of ischemia, status of co-morbid conditions and functional impairment.