Acquired right atrial blood cyst: a hitherto unrecognized complication of cardiac operation.

Blood-filled cysts within the heart are rare anomalies, usually congenital, and are seen predominately in infants. We report an unusual case of a 68-year-old woman with an acquired right atrial blood-filled cyst that developed after mitral and tricuspid valve operation and that was detected using 2-dimensional echocardiography. We propose that surgical trauma resulted in the formation of the cyst.