Platypnea-orthodeoxia syndrome related to the patent foramen ovale and atrial septal aneurysm

The platypnea-orthodeoxia syndrome is a rare condition characterized by postural dyspnea and hypoxemia that disappear or diminish in lying position, so it can be difficult to recognize without close assessment of the patient's pattern of dyspnea. The syndrome is commonly associated to an intra-cardiac right-to-left shunt through a patent foramen ovale as the most frequently reported site of the shunt. Platypnea-orthodeoxia syndrome can be the cause of refractory hypoxemia leading to pulmonary hypertension, whereby, if suspected, contrast echocardiography in supine as well as in upright position should be performed. We are presenting a case of an unrecognized platypnea-orthodeoxia syndrome because of a patent foramen ovale and atrial septal aneurysm, with developed chronic complications due to long-standing hypoxemia. This case highlights the need of a high index of suspicion to diagnose the syndrome on time and the necessity of careful echocardiographic evaluation.