Diagnosing and understanding the mechanisms behind orthodeoxia syndrome

Abstract

Orthodeoxia is a rare clinical syndrome characterized by deoxygenation in the upright position and relieved by recumbency. Our rounds illustrate how cardiovascular imaging and echocardiography can be used to diagnose the etiology of this syndrome with respect to its association with patent foramen ovale (PFO) and ascending aortic aneurysms. The rounds also demonstrate the use of peri-operative transesophageal echocardiography (TEE) in understanding the mechanisms contributing to the condition and aid in appropriately planning medical and surgical management.The purpose of this Perioperative Cardiovascular Rounds article is to illustrate how cardiovascular imaging and echocardiography can be used to diagnose the etiology of the rare clinical syndrome, orthodeoxia, which is characterized by deoxygenation following sitting or standing from a recumbent position. In this case, the rounds also demonstrate the use of perioperative transesophageal echocardiography (TEE) to help understand the mechanisms contributing to the condition and plan appropriate medical and surgical management. Written consent for publication of this article was obtained from the patient's son who has power of attorney.A 76-year-old male presented to a community hospital with sudden onset chest pain, dyspnea, and diaphoresis. His medical history was remarkable for hypertension and hyperlipidemia. He was an ex-smoker of 40 years and he denied excessive alcohol intake. The patient was diagnosed in the emergency room with a non-ST segment elevation myocardial infarction and he was treated medically. Coronary angiography revealed severe three-vessel disease, and a transthoracic echocardiogram demonstrated normal left and right ventricular function with inferior wall hypokinesis. He was referred to our institution for consideration of coronary artery bypass grafting.While awaiting surgery, the patient continued to experience intermittent chest pain, which was relieved by nitroglycerine spray. His blood pressure, pulse, and respiratory rate were within normal limits. Physical examination revealed normal heart sounds with no audible murmur or jugulovenous distension. However, pulse oximetry revealed an oxygen saturation (SpO 2 ) level of 87% with a fractional inspired oxygen concentration (F I O 2 ) of 0.21. There was no improvement noted after applying oxygen via a facemask at F I O 2 of 0.5. Electrocardiography was unremarkable, with the exception of lateral T-wave flattening. Chest radiography noted cardiomegaly in the left ventricular configuration with minor left-sided basal atelectasis. Arterial blood gas analysis following commencement of non-invasive ventilation at F I O 2 of 1.0 revealed an arterial oxygen saturation level of 91% (PaO 2 61 mmHg). Computed tomography (CT) imaging of the patient's thorax with radiocontrast failed to show any evidence of pulmonary embolism. Incidental findings were very mild peripheral interstitial Electronic supplementary material The online version of this article

Platypnea-orthodeoxia Syndrome Caused by a Latent Atrial Septal Defect

“…The bulging of the aortic root above the tricuspid orifice may behave functionally like an acquired cor triatriatum dexter (6). A previous report has described a large aneurysm of the ascending aorta that caused a significant lateral displacement of the superior vena cava (SVC) and considerable compression of the right atrium, thus leading to the development of a direct shunt between the vena cava and the left atrium across a PFO (8). Furthermore, the enlargement of the ascending aorta rotates the heart counterclockwise, thus distorting the position of the atrial septum relative to the caval inflow, and directing the right atrial venous inflow toward the PFO (9).…”