AIMS: To investigate the relationships between coronary flow reserve (CFR), left ventricular (LV) systolic function, and myocardial viability in patients with acute myocardial infarction (AMI). METHODS AND RESULTS: In 149 patients with a first AMI, we estimated CFR non-invasively and assessed LV systolic function with low-dose dobutamine Doppler echocardiography (LDDE), which also identified viability. Resting echocardiographic variables did not differ between patients with preserved (54.4%) and low CFR (45.6%). During LDDE, longitudinal LV function was decreased [9.5 cm/s (8;11.3) vs. 10.6 cm/s (8.5;12.5), P = 0.04] and end-systolic volume increased [49.5 mL (38;66) vs. 42 (31;61), P = 0.04] in patients with low compared with preserved CFR. Among 87 (58%) patients with resting wall motion abnormalities, 28 met the criteria for viability. One of 53 (2%) met the criteria for viability in patients with CFR 2, P < 0.0001. CONCLUSION: Resting echocardiographic parameters were similar in patient groups. During LDDE, patients with reduced CFR had increased LV size and compromised longitudinal function of LV and were less likely to have evidence of myocardial viability.