Anticoagulation during Procedure
Baseline activated clotting time (ACT) was measured before an initial bolus injection of unfractionated heparin (UFH). Then, a bolus of UFH (80-120 IU/kg) was administered. ACT was measured every 10-20 minutes after the first UFH shot, and additional UFH boluses (20-60 IU/kg) were administered before trans-septal puncture in order to reach optimal ACT (>300 sec) for AF ablation.10 The time from the baseline ACT measurement and the amount of UFH to achieve the optimal ACT were calculated. During the procedure, ACT was measured every 20-30 minutes; additional UFH boluses were intermittently administered to maintain the ACT >300 sec. All left atrial sheaths were regularly flushed with heparinized saline to avoid clot formation within the sheaths. The total amount of UFH required for the procedure was also calculated. After the procedure, UFH was neutralized with protamine sulfate