Catheter ablation
Catheter ablation was performed using an open-irrigated, 3.5-mm-tip contact force-sensing ablation catheter (THERMOCOOL SMARTTOUCH, Biosense Webster, Inc.). The radiofrequency energy output was adjusted to 25–35 W, at a flow rate of 17–30 mL/min, with a maximum temperature of 42 °C. The contact force was targeted at 10–30 g, and a maximum threshold of 50 g was set for all cases. PVI was first performed in all patients during AF. Additional ablations, including linear ablation, such as the LA posterior wall isolation (LAPWI) and mitral isthmus linear block, complex fractionated atrial electrogram (CFAE) ablation, or elimination of drivers identified by CARTOFINDER, were applied with the end point of termination of AF. The choice of additional ablations was dependent on operator discretion. If AF was converted into atrial tachycardia (AT), subsequent ablation was performed for the AT. External cardioversion was performed in cases in which the heart rhythm of the patient did not convert to sinus rhythm at the end of the ablation.