Paroxysmal atrial fibrillation due to left atrial appendage herniation and review of the literature.

The incidence of the isolated form of partial absence of the pericardium is a rare finding. The authors present a case of an isolated left sided pericardial defect with intrathoracic protrusion of the left atrial appendage found during a left upper lobectomy for lung cancer, unrecognized after serial echocardiographs and computed tomography scan of the thorax. The patient suffered from episodes of atrial fibrillation which disappeared after pericardial defect repair without antiarrhythmic medication.