Collection of surgical records
We confirmed the record of CS and the Maze procedure before CA. Cryo ablation using the Cardioblate CryoFlex2 (Medtronic Inc., Minneapolis, MN, United States) was performed at -60 to -90 degrees for 60 to 180 seconds, and RF ablation was performed as reported previously using the Cardioblate10 (Medtronic) or the Atricure11 (AtriCure Inc., Cincinnati, OH, United States).