Prenatal diagnosis of an aneurysm of the right atrium.

Congenital aneurysm of the right atrium was diagnosed in a 17-week fetus. It appeared as an outward bulge of the right atrium which doubled its size. The aneurysm was akinetic. Flow across the atrioventricular valves appeared unobstructed. The fetus had no evidence of cardiac failure. The patient elected to terminate the pregnancy. Autopsy results were confirmatory.