Recurrent transient ischemic attacks in a patient with intrapulmonary arteriovenous shunting detected after closure of a patent foramen ovale.

Paradoxical embolism through right-to-left shunts is widely accepted as a potential cause of cerebral ischemia. Contrast echocardiography is an excellent tool for detection of these shunts. The timing of the appearance of bubbles in the left atrium (ie, early vs late) allows differentiation of foramen ovale patency from intrapulmonary shunting as a result of arteriovenous malformations. We report a patient with recurrent neurologic deficit after surgical closure of a patent foramen ovale. Transesophageal echocardiography demonstrated residual right-to-left shunting from previously unrecognized pulmonary arteriovenous malformations associated with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu). This case illustrates the fact that contrast echocardiography may fail to identify intrapulmonary shunts when a resting patent foramen ovale coexists.