The aims of this study were to assess the effectiveness of 2 automated electrocardiogram interpretation programs in patients with suspected acute coronary syndrome transported to hospital by ambulance in 1 rural region of Denmark with hospital discharge diagnosis used as the gold standard and to assess the effectiveness of cardiologists' triage decisions for these patients based on initial electrocardiogram. Twelve-lead electrocardiograms were recorded in ambulances using a LIFEPAK 12 monitor/defibrillator (Physio-Control, Inc., Redmond, Washington) and transmitted digitally to an attending cardiologist. If a diagnosis of ST elevation myocardial infarction was made, a patient was taken to a regional interventional center for primary percutaneous coronary intervention or to a local hospital. One thousand consecutive digital electrocardiograms and corresponding interpretations from LIFEPAK 12 were available, and these were subsequently interpreted by the University of Glasgow program. Electrocardiogram interpretations and cardiologists' decisions were compared to hospital discharge diagnoses. The sensitivity, specificity, and positive predictive values for a report of ST elevation myocardial infarction with respect to discharge diagnosis were 78%, 91%, and 81% for LIFEPAK 12 and 78%, 94%, and 87% for the Glasgow program. Corresponding data for attending cardiologists were 85%, 90%, and 81%. In conclusion, the Glasgow program had significantly higher specificity than the LIFEPAK 12 program (p = 0.02) and the cardiologists (p = 0.004). Triage decisions were effective, with good agreement between cardiologists' decisions and discharge diagnoses.