The role of percutaneous transluminal coronary angioplasty (PTCA) in the subacute or chronic phases of myocardial infarction remains controversial. This study investigates the usefulness of dobutamine contrast left ventriculography in a single session with coronary angiography for predicting the improvement of ventricular function after PTCA. The study group consisted of 30 patients in whom a contrast left ventricular angiogram and PTCA were performed after a first myocardial infarction. The centerline method was used to calculate dysfunction extent at baseline and its variation during dobutamine infusion at 7.5 microg/kg/min; contractile reserve was defined as a significant (> or = 15%) reduction of dysfunction extent. A second ventricular angiogram was performed 6 months later in all patients. Abnormal wall motion extent decreased at 6 months after PTCA (84+/-21% vs 70+/-29%, p = 0.0001). Wall motion improvement after PTCA correlated with the response to dobutamine (r = 0.54, p = 0.002). Ten patients showed a significant reduction (> or = 15%) of dysfunction extent at 6 months; dobutamine testing had a 80% sensitivity, 84% specificity, 67% positive predictive value, and 89% negative predictive value in detecting regional function improvement. In the subgroup of 21 patients without restenosis, both the correlation between dysfunction improvement after PTCA and response to dobutamine (r = 0.72, p = 0.0001) and the accuracy of dobutamine testing (sensitivity 88%, specificity 92%, positive predictive value 88%, and negative predictive value 92%) increased. The ejection fraction significantly increased (>5%) after PTCA in 6 patients; dobutamine testing had a 67% sensitivity, 74% specificity, 44% positive predictive value, and 88% negative predictive value in predicting the increase in the ejection fraction. In the subgroup without restenosis the improvement of the ejection fraction correlated with the response to dobutamine (r = 0.63, p = 0.007), and the sensitivity of dobutamine testing was 80%, specificity 83%, positive predictive value 67%, and negative predictive value 91%. In conclusion, dobutamine contrast left ventriculography testing in the same session as coronary angiography predicts regional function and ejection fraction improvement after PTCA in postinfarction patients, particularly when restenosis does not develop.