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Updated: Jun 20, 2026

Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Platypnea-orthodeoxia syndrome: a diagnostic challenge
Kavit A Desouza1, Shantanu Saraswat, Shilpa A DeSouza
1Department of Internal Medicine, Louisiana State University Health Sciences Center, Shreveport, LA 71103, USA. Desouza@seas.wustl.edu
Abstract:
Platypnea-orthodeoxia (P-O) syndrome is an underdiagnosed condition characterized by dyspnea and deoxygenation accompanying a change from a recumbent to an upright position. It is caused by increased right-to-left shunting of blood on assuming an upright position. The diagnosis of this shunt is often challenging. A case where a diagnosis was missed despite performing a tilt transesophageal echocardiogram with bubble study and a technetium labeled macroaggregated albumin scan is presented. However, a large patent foramen ovale (PFO) was found on autopsy. A brief overview of the diagnostic workup and management of this condition along with methods to increase the sensitivity of diagnostic tests is discussed.
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