The aim of this study was to assess the effect of thrombolysis versus heparin treatment on echocardiographic parameters and clinical outcome, during hospitalization and within the first 180 days after admission, in patients with first episode of submassive pulmonary embolism (SPE) and right ventricle dysfunction (RVD).METHODS:Consecutive patients (age, 18-75 years) with a first episode of SPE, symptoms onset since no more than 6 hours, normal blood pressure (>100 mm Hg), echocardiographic evidence of RVD and positive lung spiral computed tomography were double-blind randomized: 1 group received 100 mg of alteplase (10-mg bolus, followed by a 90-mg intravenous infusion over a period of 2 hours), while the other group received matching placebo. In addition to alteplase or placebo, both groups received an unfractionated heparin treatment. Echocardiogram was performed at admission, at 24, 48 and 72 hours, at discharge and at 3 and at 6 months after randomization.RESULTS:Seventy-two patients were included into the study; 37 were assigned to thrombolysis and 35 to placebo. Both groups were well matched with regard to features and clinical presentation. Thrombolysis group showed a significant early improvement of RV function compared with heparin group, and this improvement was observed also during the follow-up (180 days). The same group also showed significant reduction in clinical events during the hospitalization and follow-up.CONCLUSIONS:Our data suggest that, in hemodynamically stable patients with SPE, thrombolysis shows an earliest reduction of RVD and a more favorable trend in clinical outcome, so, it could merit consideration in SPE.