Myocardial disorder or microvascular disorder can cause impairment of coronary flow reserve in patients without epicardial coronary artery stenosis. This study investigated whether infarcted myocardium influences the coronary flow reserve using transesophageal echocardiography. The coronary flow reserve was examined in 15 patients with anterior myocardial infarction without residual coronary artery stenosis in the chronic phase. The patients underwent 201Tl scintigraphy and were classified into two groups. Group I included six patients without salvaged myocardium and group II included nine patients with salvaged myocardium. The coronary blood flow velocity at the proximal part of the left anterior descending coronary artery (LAD) was evaluated by transesophageal echocardiography before and after dipyridamole administration (0.56 mg/kg/4 min). The ratios of the diastolic peak and mean velocities at hyperemia versus baseline were used as indices of coronary flow reserve (P-CFR and M-CFR, respectively). P-CFR and M-CFR were 1.7 +/- 0.3 and 1.5 +/- 0.4 in group I, and 2.9 +/- 0.5 and 2.7 +/- 0.6 in group II, respectively. Control subjects (n = 7) had P-CFR and M-CFR of 3.8 +/- 0.9 and 3.9 +/- 1.7, respectively. Coronary flow reserve decreased in patients with myocardial infarction, especially in patients without salvaged myocardium in the infarcted area. Infarcted myocardium has an important influence on coronary flow reserve, and transesophageal echocardiography is useful for evaluating coronary flow reserve.