BACKGROUND Ventricular remodeling after acute myocardial infarction is a precursor of the development of overt heart failure and is an important indicator of mortality. However, clinical and angiographic determinants of ventricular remodeling have not been fully elucidated. The purpose of the present study was to evaluate the effects of long-standing preinfarction angina and the late reperfusion of the infarct-related coronary artery on ventricular remodeling and function. METHODS Coronary angiography and left ventricular cineangiography were performed 35 +/- 16 days after the onset of acute myocardial infarction in 80 patients with a relatively recent anterior Q-wave myocardial infarction who had received conventional therapy. RESULTS In patients with preinfarction angina that occurred more than 1 week before the onset of myocardial infarction, the left ventricular size and ejection fraction were better preserved than in those without preinfarction angina. On the other hand, the late reperfusion of the infarct-related coronary artery did not affect ventricular remodeling. CONCLUSIONS Our results indicate that the presence of residual flow to the infarct area through the collateral circulation, presumably developed by repetitive ischemic stimuli, appears to be a crucial determinant of subsequent left ventricular size and function in patients with acute myocardial infarction who have had conventional therapy.