Platypnea-orthodeoxia syndrome related to an aortic aneurysm combined withan aneurysm of the atrial septum

We report the case of a 71-year-old man bearing a severe right-to-left shun t through a patent foramen ovale in the absence of elevated right-sided hea rt or pulmonary artery pressures. He presented with platypnea-orthodeoxia s yndrome, but he had no pulmonary or extracardiac diseases that are known to be associated with this syndrome. Chest radiography showed a bulky aneurys m of the thoracic aorta. A peripheral contrast transesophageal echocardiogr aphy demonstrated a large right-to-left shunt through a patent foramen oval e. In addition, the atrial septum was severely deformed by an aneurysm incl uding this patent foramen ovale. We hypothesized that the opening of the fo ramen ovale was the result of a mechanical deformation of the atrial septum by two contributing factors: the aneurysm of the thoracic aorta and the an eurysm of the septum itself.