Platypnea-Orthodeoxia Syndrome With Atrial Septal Defect and Ectatic Aortic Root: A Case Report and Review of the Literature

Abstract

Platypnea-orthodeoxia syndrome (POS) is a rare and underdiagnosed disease characterized by dyspnea in the upright position (platypnea) with simultaneous hypoxemia (orthodeoxia) that is relieved by recumbency. The physiopathological mechanisms involved are mediated by intracardiac shunts, pulmonary arteriovenous shunts or ventilation/perfusion mismatch. When POS is caused by a cardiac pathology, there is an anatomical (interatrial communication) and a functional component (as a dilated aorta or pneumectomy) working together to cause a right to left shunt without a constant right to left pressure gradient. Diagnosis is suspected through pulse oximetry verifying orthodeoxia. Confirmation usually is made by transesophageal echocardiography with bubble study to visualize the shunt. Percutaneous closure of the shunt is effective in most cases of cardiac POS. We report a case of an 87-year-old woman with POS related to a patent foramen ovale and an ectatic aorta followed by a review of the literature.