Pulmonary vein (PV) isolation is very important in atrial fibrillation (AF) catheter ablation. PV reconnection is one of the main reasons in AF recurrence. Contact force-sensing catheter is a new catheter which has valuable tools to monitor and increase the efficacy of PV isolation. Previous paper reported the efficacy of contact force-sensing catheter on immediate PV isolation and outcome. However, there might be confounding factor as inter-individual variation. Therefore, we would like to compare the efficacy of contact force-sensing catheter within same patient but different veins.