Beneficial effect of residual flow to the infarct region on left ventricular volume changes after acute myocardial infarction

To determine the relationship between alterations in left ventricular (LV) volumes and residual flow to the infarct region after myocardial infarction (MI), 57 patients with a first acute transmural MI underwent two-dimensional echocardiography within 48 hours of infarction and after 1 month. A reduction in ST segment elevation by ≥35% of the peak value of ST segment elevation within the initial 6 hours was used as an indirect indicator for early reperfusion of the infarct-related artery (IRA). IRA patency and collateral circulation were assessed by coronary arteriography performed at 1 month. LV volumes increased in patients with a persistent ST segment elevation within the initial 6 hours of infarction and in those with a totally occluded IRA without collaterals. However, LV volumes were unchanged in patients with early reperfusion and in those who had subtotally occluded IRA or who had collateral circulation. LV dilatation (≥20% increase in end-diastolic volume) occurred less often when early reperfusion and angiographically patent IRA or collateral supply to the infarct zone were present. This prospective study indicates that residual flow to the infarct region may exert a beneficial effect on LV volume changes after acute MI.