Abstract
Platypnea-orthodeoxia syndrome (POS) attributed to patent foramen ovale (PFO) can be caused by a variety of clinical conditions. A 70-year-old woman was admitted to our hospital for further evaluation of POS. Her symptoms developed along with the spread of infiltrative shadows in both lower lung fields during the preceding 2 years. Contrast transthoracic echocardiography with agitated saline revealed grade III intracardiac right-to-left shunting, presumably across a PFO. Transesophageal echocardiography demonstrated severe tricuspid regurgitation (TR) caused by the prolapse of the anterior leaflet. Bidirectional shunt flow, mainly from right-to-left across a PFO, that increased in the sitting position was also observed. She was diagnosed as having PFO associated with severe primary TR. Therefore, tricuspid valve repair and direct PFO closure were performed. Her symptoms resolved completely soon after the operation and her oxygen saturation was maintained. This patient's disease seemed to have worsened with the spread of pulmonary parenchymal involvement, which caused ventilation-perfusion mismatch and elevation of alveolar pressures. Echocardiography is an essential imaging modality in addition to other diagnostic examinations and imaging studies when assessing the pathogenesis in patients with POS. LEARNING OBJECTIVE: Platypnea-orthodeoxia syndrome (POS) associated with patent foramen ovale may be caused by a variety of clinical conditions, and POS in our patient may be caused by the worsening of pulmonary parenchymal involvement. Examinations to evaluate all causes of POS are essential for making the diagnosis. Contrast transthoracic echocardiography was useful in assessing the cause of POS.