Echocardiography has proved useful in detecting right-sided heart thrombi in cases of pulmonary embolization. We found echocardiographic evidence of right-sided cardiac thrombi in six of seven patients affected by pulmonary embolism referred to our hospital within the past five months. In one patient with clinical evidence of pulmonary and paradoxic embolization, echocardiography revealed, besides thrombi within the inferior cava and right atrium, a transient, wide, systolic movement of the valvula foraminis ovalis toward the left atrium, suggesting an interatrial communication that was confirmed by contrast echocardiography. Five patients had a good outcome, with disappearance of the thrombi following IV heparin therapy, and one patient died.