Right atrial thromboemboli: clinical, echocardiographic and pathophysiologic manifestations.

In six patients with clinically unsuspected right atrial thromboemboli the diagnosis was made with two-dimensional echocardiography. Five patients had pulmonary emboli, and one had systemic embolization. Three patients had congestive cardiomyopathy, two with tricuspid regurgitation; of the remaining three, one had cor pulmonale complicated by tricuspid regurgitation, one had thrombophlebitis and one had no discernible cardiac illness. Four patients had dizziness or syncope, four had dyspnea, three had chest pain, three had hypotension and tow had cyanosis. Five patients were treated with thrombolytic or anticoagulant therapy, or a combination of the two. In three patients, surgical removal of the thrombus was undertaken because of recurrent pulmonary emboli or tricuspid regurgitation, or both, and progressive right heart failure. The thromboemboli were removed in all three, but one patient died. On two-dimensional echocardiography, four of the six patients' thromboemboli were snake-like, unattached to the right atrium and prolapsed freely across the tricuspid valve into the right ventricle in diastole and back into the right atrium in systole. The other two patients' thromboemboli were attached to the right atrium and did not prolapse across the tricuspid valve. Our cases, together with a review of other reports, suggest that right atrial thromboemboli: 1) can be accurately diagnosed by two-dimensional echocardiography; and 2) result from two different pathophysiologic mechanisms developing a) in situ, either on a foreign body or secondary to reduced cardiac output, or b) as a result of an embolus from systemic vein thromboses.