Platypnea-orthodeoxia syndrome in review: defining a new disease?

Platypnea-orthodeoxia syndrome is an intriguing condition that comprehends multiple pathologic phenomena. It requires a high clinical suspicion and is probably underdiagnosed. Its identification has therapeutic implications and can have a huge impact on the patient's everyday life. We made a review of the literature and analyzed 188 cases described thus far, trying to identify the underlying mechanisms and risk factors. We propose that a separate entity is created within the spectrum of platypnea-orthodeoxia syndrome that is responsible for the majority of cases, namely platypnea-orthodeoxia disease, which would be defined as the existence of an interatrial communication, with a right-to-left shunt, normal pressure in the right atrium and, of course, platypnea and orthodeoxia. Most patients with this disease were submitted to percutaneous closure of the patent foramen ovale or atrial septal defect, with favorable results, making it the first-line therapeutic approach nowadays.