Hospital Mortality of Myocardial Infarction, Before and After Coronary Care

The effect of a coronary care unit on the mortality rate from acute myocardial infarction in an unselected total hospital series, matched for prognostic factors, is reported. In the five years before the establishment of the unit the rate did not vary significantly from a mean of 36%. Cases observed for 12 months before and for nine months after the unit opened were comparable for most major prognostic factors. The exceptions were those factors which could be expected to worsen, not improve, results. In spite of this, after the introduction of the unit there was a statistically significant fall in the hospital mortality rate to 24%. Prognosis was improved in those patients aged less than 70 years, those with neither previous cardiac failure nor diabetes, those admitted within 4 hr of infarction, those with pain of less than 4 hours' duration, and those with reinfarction or cardiac failure during the present admission. Mortality also fell in those without pneumonia. The outcome was not significantly altered in the elderly, the diabetic, or in those with a past history of cardiac failure. There was similarly no significant change in the prognosis of those whose admission to hospital was delayed, those with pain of more than 4 hours' duration, or in those with pulmonary oedema or shock, bundle branch block, a lactate dehydrogenase level (LDH) above 2,000 Berger-Broida units/ml, or pneumonia.