Platypnea-Orthodeoxia Syndrome Associated With a Right-to-Left Cardiac Shunt Detected by Lung Perfusion Scintigraphy

Sep 30, 2026

Platypnea-orthodeoxia syndrome is a rare disorder marked by posture-dependent right-to-left shunting, causing dyspnea in the upright position that improves when supine. Standard confirmation often requires echocardiographic microbubble testing or transesophageal echocardiography, which can be impractical in older adults or patients with psychiatric illness due to cooperation needs and cardiology-dependent interpretation. This case report details a 64-year-old woman with persistent hypoxemia in whom lung perfusion scintigraphy demonstrated a right-to-left shunt, while CT excluded intrapulmonary shunting and catheterization confirmed patent foramen ovale.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Introduction

Case Report

Diagnostic approach

Conclusions

e-ISSN 1941-5923 © Am J Case Rep, 2025; 26: e949642 DOI: 10. 12659/AJCR.949642 Received: 2025.04.30 Accepted: 2025.10.16 Available online: 2025.11.15 Published: 2025.12.23 Authors’ Contribution: Study Design A Data Collection B Statistical Analysis C Data Interpretation D Manuscript Preparation E Literature Search F Funds Collection G ABCDEFG 1,2 CDE 1 DE 3 DE 1 DE 1 CDE 1 Corresponding Author: Financial support: Conflict of interest: Platypnea-Orthodeoxia Syndrome Associated With a Right-to-Left Cardiac Shunt Detected by Lung Perfusion Scintigraphy Yusuke Nakano Hirohiko Ando Akinori Satake Reiji Goto Kentaro Mukai Tetsuya Amano Yusuke Nakano, e-mail: [nakanoy@aichi-med-u.ac.jp](nakanoy@aichi-med-u.ac.jp) None declared None declared 1 Department of Cardiology, Aichi Medical University, Nagakute, Aichi, Japan 2 Department of Internal Medicine, AISAN Clinic, Tsushima, Aichi, Japan 3 Department of Cardiology, Narita Memorial Hospital, Toyohashi, Aichi, Japan Patient: Female, 64-year-old Final Diagnosis: Platypnea orthodeoxia syndrome Symptoms: Hypoxemia Clinical Procedure: — Specialty: Cardiology Objective: Rare disease Background: Platypnea-orthodeoxia syndrome is a rare condition characterized by posture-dependent right-to-left shunting, resulting in dyspnea in the upright position that improves when supine. Diagnosis usually relies on echocardiographic microbubble testing or transesophageal echocardiography, which require patient cooperation and cardiology support and may be impractical in older or psychiatric patients. Lung perfusion scintigraphy provides a practical, noninvasive alternative for detecting shunts without requiring cooperation or cardiologist involvement. This report describes a case of platypnea-orthodeoxia syndrome associated with a right-to-left cardiac shunt that was detected by lung perfusion scintigraphy. Case Report: A 64-year-old woman with hypertension and severe bipolar disorder was admitted after being found unconscious. She displayed persistent hypoxemia despite oxygen supplementation. Laboratory findings were unremarkable; imaging revealed a dilated aortic root compressing the right atrium but no evidence of pulmonary embolism or pneumonia. Transthoracic echocardiography showed no definitive shunt. Microbubble testing or transesophageal echocardiography could not be performed due to psychiatric instability and lack of immediate cardiology support. On hospital day 2, lung perfusion scintigraphy demonstrated a right-to-left shunt, whereas chest computed tomography excluded intrapulmonary shunting. Cardiac catheterization on day 5 confirmed a patent foramen ovale with right atrial compression, establishing the diagnosis of platypnea-orthodeoxia syndrome. Shunt closure was deferred due to the unavailability of a specialist for percutaneous closure. At 12 months of follow-up, the patient remained untreated. Conclusions: Lung perfusion scintigraphy represents a noninvasive and effective diagnostic tool for identifying intracardiac shunting in patients with unexplained hypoxemia when microbubble testing or transesophageal echocardiography is not feasible. Keywords: Bipolar Disorder • Cardiac Imaging Techniques • Radionuclide Imaging • Technetium Tc 99m Aggregated Albumin Full-text PDF: [https://www.amjcaserep.com/abstract/index/idArt/949642](https://www.amjcaserep.com/abstract/index/idArt/949642) 1363 2 2 14 Publisher’s note: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher This work is licensed under Creative Common AttributionNonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) e949642-1 Indexed in: [PMC] [PubMed] [Emergi

FAQs

What defines platypnea-orthodeoxia syndrome clinically?

It is characterized by posture-dependent right-to-left shunting that leads to dyspnea in the upright position and improvement when supine.

Why can echocardiography-based microbubble testing be difficult in some patients?

It requires patient cooperation (e.g., breath-holding) and typically depends on cardiology involvement, which may be challenging in older adults or psychiatric patients.

How did lung perfusion scintigraphy contribute to the diagnosis in this case?

On hospital day 2, lung perfusion scintigraphy demonstrated a right-to-left shunt, supporting the diagnosis when other confirmatory echocardiographic methods were not feasible.

Sep 30, 2026

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