Successful surgical correction of symptomatic cor triatriatum dexter.

An unusual case of cor triatriatum dexter is presented. Abnormal embryologic development of the eustachian valve caused nearly complete septation of the right atrium in a 67-year-old woman. Multiple supraventricular arrhythmias prompted clinical evaluation and diagnosis. Surgical excision of the anomalous membrane resulted in complete relief from arrhythmias and a clinical cure. Cor triatriatum dexter is rare and is infrequently diagnosed before postmortem study; however, once the diagnosis is extablished, the condition is amenable to a relatively simple surgical correction. Supraventricular tachycardia has not previously been reported to be associated with cor triatriatum dexter. We believe this is the first case in which such arrhythmias led to early diagnosis and successful surgical correction.