Applications for epicardial ablation. The rigid pericardial endoscope-assisted Maze procedure was evaluated. A: in the right lateral recumbent position, the left atrial appendage (LAA) was confirmed. B: By avoiding LAA by a guide wire, the ostium of the left pulmonary vein (LPV) was identified. C: The connection of the left atrium and the ostium of the LPV was securely clamped by forceps without major injury. D1: first diagonal branch; LAA: left atrial appendage; LPV: left pulmonary vein.