Percutaneous transcatheter closure of patent foramen ovale or atrial septal defect is an alternative to surgery for the treatment of platypnea-orthodeoxia syndrome. We report the hemodynamic characteristics and clinical and echocardiographic outcomes of 18 patients with platypnea-orthodeoxia syndrome that underwent transcatheter closure of patent foramen ovale or atrial septal defect. Successful closure was achieved in all patients with no in-hospital mortality or adverse events. Complete resolution of symptoms was seen in all patients and mean oxygen saturation increased from 82.6 +/- 5.4% to 96.1+/-2.2% post-procedure (p < 0.01).