Localized pericardial hematoma presenting with acute hypoxemia.

Localized pericardial hematomas after cardiac surgery may have atypical clinical presentations due to regional alterations in cardiac function and hemodynamics. We report a case of extravascular thrombus that compressed the main pulmonary artery and produced acute hypoxemia due to right-to-left shunting across a patent foramen ovale. We review the pathophysiology leading to this finding and the echocardiographic studies that established the diagnosis.