RESUMO
Myocardial infarction is among the most common diagnoses in patients admitted to hospitals in western countries, and its rapid diagnosis is of utmost importance. This study was conducted to determine the most sensitive double-marker cardiac isoenzyme of creatinine kinase, troponin I, and myoglobin for diagnosing acute myocardial infarction. This was an observational-analytic research on a diagnostic test conducted on 256 patients who had referred to the emergency department with chest pain from 4 to 24 hours before their referral. They were sorted equally into two groups of 4-14 hours and 15-24 hours from onset of pain, each group including 128 patients. In the first time period, the combination of troponin and myoglobin had the highest sensitivity [sensitivity = 97.3%, specificity = 98.1%], whereas the combination of double-marker and troponin proved the most sensitive [sensitivity = 100%, specificity = 96.3%].The double-marker combination of troponin and myoglobin is more appropriate for the first time period [i.e. during the first 24 hours from the onset of chest pain],while it would be more helpful to use the combination of troponin during the second period of time.