The cardioprotective role of preinfarction angina as shown in outcomes of patients after first myocardial infarction.

This prospective study evaluated the relationship between preinfarction angina (2 months before a 1st acute myocardial infarction) and the extent of postinfarction myocardial injury, myocardial perfusion, contractile function, and late recovery of global left ventricular contractile function. We enrolled 46 patients who had been admitted for a 1st, single-vessel-disease, acute myocardial infarction. Low-dose dobutamine echocardiography and technetium-99m-tetrofosmin scintigraphy were performed on all patients 7 to 10 days after acute myocardial infarction; and resting echocardiography was performed 7 to 12 months later. Twenty-seven of 46 (58.7%) patients had experienced angina before acute myocardial infarction, and 19 of 46 (41.3%) had not. There was no difference between the 2 groups in acute basal left ventricular ejection fraction (P=0.17) or in basal wall motion score index (P=0.521). The maximal creatine kinase-MB level was lower in the preinfarction-angina group (P=0.039). Patients with preinfarction angina had significantly more myocardial segments with preserved regional contractile function (P <0.0001) and significantly fewer segments with less than 50% perfusion (P=0.008). Stepwise regression analysis identified preinfarction angina (r2=0.317, P=0.032) as a significant predictor of the percentage of left ventricular ejection fraction recovery after the follow-up period. In our study, preinfarction angina was associated with decreased infarct size and with better protection of global and regional left ventricular contractility and improved preservation of the microvasculature. A history of preinfarction angina should be of value in predicting the late clinical outcomes of patients after a 1st acute myocardial infarction.