Platypnoea–orthodeoxia syndrome induced by short-term weight loss: a case series

BACKGROUND: Platypnoea–orthodeoxia syndrome (POS) is an uncommon condition characterized by dyspnoea and arterial desaturation in the standing or sitting position that improves in the supine position. CASE SUMMARY: We report two cases of POS caused by an atrial septal defect (ASD) and a patent foramen ovale (PFO). Both cases reported a recent decrease in body weight of more than 10 kg in a short time period. Transoesophageal echocardiography (TOE) with agitated saline bubble study revealed and a large amount of contrast bubble through the ASD (Patient 1) or the PFO (Patient 2) from the right atrium to the left atrium in the sitting position. Both patients were diagnosed by the finding of positional dyspnoea and the results of TOE using agitated saline bubble contrast. DISCUSSION: Taken together, their presentations suggest that weight loss in a short time period could be a pathogenic factor for POS.