A black box congenital heart defect: Anomalous superior vena cava drainage into the left atrium.

A 25-year-old pregnant woman with low oxygen saturation due to unclear congenital heart disease was admitted. During work-up the rare anomaly of superior vena cava drainage to the left atrium was diagnosed by transthoracic bubble test with agitated saline. The pathology was later confirmed by contrast multislice computed tomography angiography after delivery.