Figure 1: Lesion sets. (a): traditional Cox-maze III operation, (b): Cryomaze procedure, (c): commonly employed epicardial radiofrequency ablation. The solid lines indicate the “cut and sew” incisions, and the broken lines indicate the ablation lines. MV: mitral valve, TV: tricuspid valve, IVC: inferior vena cava, SVC: superior vena cava, LAA: left atrial appendage, LSPV: left superior pulmonary vein, LIPV: left inferior pulmonary vein, RSPV: right superior pulmonary vein, and RIPV: right inferior pulmonary vein.