Right ventricular (RV) involvement is frequent during inferior wall acute myocardial infarction (AMI) and has been reported as a risk factor for in-hospital morbidity and mortality. The objectives of the present study were: (1) to evaluate in-hospital events in patients with and without RV involvement as diagnosed by abnormal flow characteristics derived from pulmonary regurgitation (PR) analysis (pressure half-time of PR, PHT(PR) < or = 150 ms and the lowest mid-diastolic to peak early diastolic velocity ratio, Vmin/Vmax < or = 0.5); and (2) to determine the influence of RV involvement in complications at long-term follow-up. Among 126 consecutively admitted patients with inferior wall AMI (mean age, 58 +/- 13 years), 101 had PR. We determined the prognostic significance of in-hospital and long-term events for the following variables: age > or = 65 years, ST-segment elevation > or = 1 mm in lead V4R, RV dilation, PHT of PR < or = 150 ms and Vmin/Vmax < or = 0.5, thrombolytic therapy, 3-vessel disease, and diabetes mellitus. We found that the PR derived Doppler index (PHT of PR < or = 150 ms and Vmin/Vmax < or = 0.5) was the only predictor of overall in-hospital clinical events (hazards ratio, 2.7, 95% confidence interval, 1.2 to 6.1, p = 0.016). At long-term follow-up (mean: 20 +/- 12 months, range 12 to 69), event-free survival analysis showed that age > or = 65 years was the only predictor of any event (relative risk, 3.7, 95% confidence interval, 2.1 to 6.3, p < 0.0001). Thus, RV involvement diagnosed with the use of PR flow-derived variables is an accurate and independent predictor of in-hospital complications. However, RV involvement does not influence long-term prognosis.