We studied with two-dimensional echocardiography and coronary angiography 2 groups of patients with one-vessel stenosis located on anterior descending (IVA) and previous acute myocardial infarction (AMI; means 19 days): 23 patients with spontaneous non-Q infarction (Group I), and 23 patients with Q infarction (Group II). Left ventricular function was better in Group I (echo score: 2.04 +/- 2.64, angiographic ejection fraction: 65.65 +/- 9.7 in Group I, echo score: 4.78 +/- 3.14, angiographic ejection fraction: 49.47 +/- 9.1 in Group II, p less than 0.001). Percent occlusion of IVA was lower in Group I and angiographic IVA caliper was significantly higher (p less than 0.05). Differences between groups were much more evident in subgroups with proximal stenosis of IVA: patients of non-Q subgroup had very good left ventricular function but frequently had post-IMA unstable angina (78%). Our results underline usefulness of aggressive diagnostic and therapeutic approach in non-Q AMI, because of higher amount of myocardial a risk.