Patent Foramen Ovale-Induced Platypnea-Orthodeoxia Syndrome: A Case Report and Literature Review.

Platypnea-orthodeoxia syndrome (POS) is a rare condition characterized by dyspnea and hypoxia worsening in the upright position and relieved in the recumbent position. POS can result from anatomical or functional conditions that cause interatrial communication or deformity of the atrial septum. Investigations with imaging and cardiac catheterization can aid in the evaluation.