An unusual case of cardiac tamponade.

A 29-year-old woman with Ebstein's anomaly on anticoagulant therapy presented with chest pain. A diagnosis of pericarditis was made once a myocardial infarction and pulmonary embolus had been excluded. She was discharged but returned shortly thereafter with fever, tachypnea and tachycardia. A repeat chest film disclosed that the cardiac silhouette had enlarged greatly since prior admission. Despite the absence of pulsus paradoxus, right heart catheterization confirmed the clinical suspicion of pericardial tamponade.