Patients were monitored continuously with a 12 lead ECG and ST segment trend monitoring and blood will be drawn at 0,3,6 hours after arrival at ED for serial myoglobin, creatine kinase MB isoenzyme (CKMB) and Troponin T (TnT) . Patients who have ECG and blood test consistent with myocardial necrosis were admitted to the CCU. A senior doctor in the ED reviewed patients who were not admitted after 6 hours of observation.