Clinical predictors of angina following myocardial infarction.

To determine if angina following myocardial infarction could be predicted before hospital discharge we prospectively evaluated 219 consecutive patients admitted to the coronary care unit with acute myocardial infarction. Of the 166 who survived to one year, angina was present before infarction in 53 per cent and after infarction in 61 per cent. Angina did not recur postinfarction in 26 per cent of the patients who had angina before infarction. However, in 47 per cent of those without previous angina it developed postinfarction. Although postinfarction angina correlated with the presence of angina before infarction (p < 0.0005), it did not correlate significantly with age, sex, site of infarction, Killip class on admission nor the presence of a previous infarction.To improve our ability to predict angina after infarction we performed exercise tests to 5 metabolic equivalents (METS), or 70 per cent of age-predicted maximal heart rate, before hospital discharge on all patients less than 70 years old who were without chest pain within four days or without overt heart failure. Of the 105 patients exercised, 31 (86 per cent) of the 36 with positive tests had angina during the subsequent year compared to only 25 (36 per cent) of the 69 with negative tests (p < 0.001). Postinfarction angina occurred in 96 per cent (23 of 24) of the patients who had both angina before infarction and a positive test, but in only 26 per cent (10 of 39) of the patients with neither finding (p < 0.001).We conclude that the presence of angina prior to infarction and a positive limited exercise test performed before hospital discharge are predictive of angina following infarction. Myocardial infarction abolishes angina in a quarter of the patients, but angina develops postinfarction in nearly half of the patients who did not have angina previously.