Occurrence of angina pectoris prior to acute myocardial infarction and its relation to prognosis

In 917 patients with acute myocardial infarction (AMI) we evaluatedthe impact of previous angina pectoris on the prognosis. Thirty-fourpercent of the patients had chronic angina prior to AMI, and22% had angina pectoris of short duration. Patients with chronicangina pectoris differed from the remaining patients havinga more frequent previous history of AMI, diabetes mellitus,hypertension, and congestive heart failure. They less frequentlydeveloped a Q-wave AMI, and had smaller infarcts according tomaximum serum-enzyme activity as compared with the remainingpatients. They had a higher one-year mortality rate (36%) ascompared with those having angina pectoris of short duration(22%), and those with no angina pectoris (26%). Their reinfarctionrate was also higher (26%) as compared with that in the othertwo groups (15% and 9% respectively). In a multivariate analysisconsidering age, sex, clinical history, initial symptoms, initialelectrocardiogram and estimated infarct size, previous chronicangina pectoris was not an independent risk factor for death,but was independently associated with the risk of reinfarction(P<0.001) Among patients with a history of angina pectoristhe outcome was related to medication prior to onset of AMIand at discharge from hospital. Patients in whom beta-blockerswere prescribed at discharge had a one-year mortality of 13%as compared with 30% in the remaining patients (P<0.001).