Atrial Septal Defect with Cyanosis Due To Over-Developed Eustachian Valve Directed Towards Left Atrium: A Very Rare Scenario.

Cyanosis in a case of ASD (atrial septal defect) without pulmonary arterial hypertension is quite rare. A patient with ASD and pneumonia is described who had a central cyanosis resulting from the drainage of deoxygenated blood from the inferior vena cava directly into the left atrium through the atrial septal defect due to the presence of an over-developed malpositioned Eustachian valve directed to the left atrium. In conclusion, ASD can present with cyanosis due to an over-developed Eustachian valve.