Echocardiographic appearances of right atrial thrombus.

A 17-year-old male presented with a four-day history of increasing shortness of breath and right basal pleuritic chest pain. Physical examination revealed central and peripheral cyanosis, sinus tachycardia, elevation of central venous pressure, hypotension, and added third heart sound. Echocardiography (M-mode and two-dimensional) showed a highly mobile mass in the right atrium apparently attached to the interatrial septum. A diagnosis of right atrial myxoma with pulmonary embolization was made and urgent surgery advised. At operation a string of thrombus in the right atrium (presumed from peripheral venous site) occluding a patent foramen ovale was found. The usefulness of echocardiography in diagnosing atrial thrombus and in differentiating clot from tumor is discussed.