Journal of the American Society of Echocardiography vol:6 issue:6 pages:624-7
Platypnea is a rare syndrome of orthostatic dyspnea frequently caused by an interatrial right-to-left shunt. The diagnosis is difficult. Assessment of arterial blood gases reveals orthostatic desaturation. In the past, definite diagnosis necessitated catheterization in the supine and upright position. Now transesophageal echocardiography on a tilt table combined with a peripheral venous contrast study provides correct diagnosis in a safe and easy way.