Patients treated in a coronary care unit without acute myocardial infarction: identification of high risk subgroup for subsequent myocardial infarction and/or cardiovascular death.

Consecutive patients admitted to a coronary care unit (CCU) during one year were studied. The diagnosis of acute myocardial infarction was not substantiated by our criteria in 206 of the patients discharged from the CCU. Of these, 193 were retrospectively followed up during one year. Seventeen of the patients (9%) died from cardiovascular causes during the 1-year period. Another 14 patients (7%) had a subsequent non-fatal acute myocardial infarction during the same period. The majority of the patients had coronary artery disease. Only 32 (17%) could be classified as non-coronary cases, and these had an excellent prognosis without any subsequent acute myocardial infarctions or deaths. The occurrence of transient ST-T shifts in serial electrocardiograms obtained during the first 3 days in hospital selected a subgroup of patients who had a high risk for subsequent non-fatal acute myocardial infarction and/or cardiovascular death. This high risk subgroup provides a basis for more aggressive diagnostic and therapeutic intervention.