We related observations in the electrocardiogram (ECG) on admission to hospital among consecutive patients hospitalized in one single hospital with acute myocardial infarction (AMI) and related the prognosis during the following 5 years to these observations. Results: Of 863 patients, 63% had ECG signs of myocardial ischemia, but only 41% had ST elevation on ED admission. Patients with ST elevation had a 5-year mortality of 44% as compared with 58% in patients without ST elevation (p < 0.001). Patients with the highest mortality were those with a pathologic ECG including signs of previous AMI, bundle branch block and pacemaker ECG, but with no ECG sign of acute ischemia. Patients with the lowest mortality were those with a nonpathologic ECG on admission. Conclusion: Among consecutive patients hospitalized with AMI, less than half had ST elevation on admission to hospital. These patients had a lower mortality during 5 years of follow-up than patients without ST elevation.