Electrocardiographic ST-segment elevation: correct identification of acute myocardial infarction (AMI) and non-AMI syndromes by emergency physicians.

OBJECTIVE: To determine the emergency physician's (EP's) ability to identify the cause of ST-segment elevation (STE) in a hypothetical chest pain patient.

METHODS: Eleven electrocardiograms (ECGs) with STE were given to EPs; the patient in each instance was a 45-year-old male with a medical history of hypertension and diabetes mellitus with the chief complaint of chest pain. The EP was asked to determine the cause of the STE and, if due to acute myocardial infarction (AMI), to decide whether thrombolytic therapy (TT) would be administered (the patient had no contraindication to such treatment). Rates of TT administration were determined; appropriate TT administration was defined as that occurring in an AMI patient, while inappropriate TT administration was defined as that in the non-AMI patient.

RESULTS: Four hundred fifty-eight EPs completed the questionnaire; levels of medical experience included the following: postgraduate year 2-3, 193 (42%); and attending, 265 (58%). The overall rate of correct interpretation of the study ECGs was 94.9% (4,782 correct interpretations out of 5,038 instances). Acute myocardial infarction with typical STE, ventricular paced rhythm, and right bundle branch block were never misinterpreted. The remaining conditions were misinterpreted with rates ranging between 9% (left bundle branch block, LBBB) and 72% (left ventricular aneurysm, LVA). The overall rate of appropriate thrombolytic agent administration was 83% (1,525 correct administrations out of 1,832 indicated administrations). The leading diagnosis for which thrombolytic agent was given inappropriately was LVA (28%), followed by benign early repolarization (23%), pericarditis (21%), and LBBB without electrocardiographic AMI (5%). Thrombolytic agent was appropriately given in all cases of AMI except when associated with atypical STE, where it was inappropriately withheld 67% of the time.

CONCLUSIONS: In this survey, EPs were asked whether they would give TT based on limited information (ECG). Certain syndromes with STE were frequently misdiagnosed. Emergency physician electrocardiographic education must focus on the proper identification of these syndromes so that TT may be appropriately utilized.