What the cardiologist should know about the management of platypnea-orthodeoxia syndrome.

Platypnea-orthodeoxia syndrome is a rare and poorly understood condition related to the development of a right-to-left intracardiac shunt at the atrial level through a benign and silent patent foramen ovale. It is usually recognized after major lung resection, recurrent pulmonary embolism or chronic lung disease. Orthostatic dyspnea and cyanosis is the prominent clinical presentation. Symptoms increase in the upright position and are relieved by recumbency. Our report describes the clinical course of a patient with severe hypoxemia after left pneumonectomy attributable to a right-to-left shunting through an atrial septal defect.