Left atrial appendage aneurysm with paroxysmal atrial fibrillation.

Aneurysm of the left atrial appendage is extremely rare, and afflicted patients most commonly present with atrial tachyarrhythmia or thromboembolism. For these patients, resection of the aneurysm is the recommended and preferred therapy. We present the case of a 57-year-old woman who was found incidentally to have a large aneurysm of the left atrial appendage presenting as atrial fibrillation. After surgical intervention with resection of the aneurysm and a Cox maze III procedure, the patient recovered and was discharged in sinus rhythm.