Idiopathic dilatation of the right atrium. A case report.

Idiopathic dilatation of the right atrium in a young woman is reported. Thoracotomy was performed for suspected pericardial cyst. Intraoperative findings suggested idiopathic right atrial dilatation, which was histologically confirmed. Two years after partial resection of the dilated right atrial wall the patient is doing well. Management of asymptomatic idiopathic dilatation of the right atrium should be medical, surgery being reserved for patients with symptoms.