Indications for admission to a coronary care unit in patients with unstable angina.

One hundred cases with an admission diagnosis of acute coronary insufficiency or unstable angina were reviewed to establish criteria for admission to a coronary care unit. Myocardial infarction was subsequently diagnosed in 20 of the patients. Ventricular tachycardia occurred in 16 patients and ventricular fibrillation in 1 patient. Clinical features found to predict an increased risk of myocardial infarction included chest pain for more than 30 minutes within 24 hours prior to admission, new nonspecific electrocardiographic abnormalities consistent with ischemia, and diaphoresis. All patients with ventricular tachydysrhythmias had presented with both prolonged chest pain prior to admission and new electrocardiographic changes. The sensitivity, specificity and predictive value of various clinical criteria for identifying patients likely to have a myocardial infarction were calculated, and criteria with very high (greater than 90%) sensitivity were identified. These could be used to establish which patients are at increased risk of myocardial infarction and therefore require admission to a coronary care unit.