We assessed the time course of the alterations of microvascular function and myocardial perfusion, as well their relation to local inotropic reserve (IR), in 21 patients who underwent successful primary coronary angioplasty for acute myocardial infarction and in whom local myocardial dysfunction persisted at hospital discharge. Coronary flow reserve (CFR) and myocardial perfusion were assessed immediately after angioplasty, and on day 1 and day 8 by intracoronary Doppler and myocardial contrast echocardiography, respectively. Dobutamine echocardiography was performed on day 7 for assessment of local IR. After angioplasty, CFR was severely altered in patients with (n = 14) and without (n = 7) IR (1.44 +/- 0.26 and 1.36 +/- 0.21, respectively; p = NS). Among patients with IR, CFR increased significantly at day 1 (2.26 +/- 0.62, p <0.005 vs acute stage) compared with those without IR (p = NS vs acute). In contrast, the extent of microvascular obstruction as defined by contrast echocardiography remained unchanged in all patients at day 1 compared with acute measurements. Microvascular obstruction decreased at day 8 in the sole subset of patients with local IR (p <0.05 vs acute stage). In patients treated by immediate coronary angioplasty for acute myocardial infarction, subsequent improvement of myocardial perfusion is associated with preexistent recruitable microvascular function in the infarct-related artery. The presence of reversible microvascular dysfunction at the early stage after acute myocardial infarction is associated with local tissue viability in humans.