Adequate Initial Heparin Dosage for Atrial Fibrillation Ablation in Patients Receiving Non-Vitamin K Antagonist Oral Anticoagulants

BACKGROUND AND OBJECTIVE: During atrial fibrillation ablation, heparin is required and is guided by the activated clotting time (ACT). Differences in the ACT before ablation and adequate initial heparin dosing in patients receiving non-vitamin K antagonist oral anticoagulants (NOACs) were examined. METHODS: Patients who received warfarin (control, N = 90), dabigatran etexilate (N = 90), rivaroxaban (N = 90) and apixaban (N = 90) were studied. A 100 U/kg dose of heparin was administered as a reliable control dose for warfarin, and the remaining patients were randomly administered 110, 120 or 130 U/kg of heparin in each NOAC group, followed by a continuous heparin infusion. RESULTS: Periprocedural thromboembolic and major bleeding were not observed. Minor bleeding occurred rarely without significant differences among the groups examined. Baseline ACTs were longer in the warfarin (152 ± 16 s) and dabigatran (153 ± 13 s) groups than in the rivaroxaban (134 ± 13 s) and apixaban (133 ± 20 s) groups. The initial bolus heparin dosages required to produce an ACT 15 min after the initial bolus that was identical to the control (333 ± 32 s) were 120 U/kg (318 ± 29 s) and 130 U/kg (339 ± 43 s) for dabigatran, 130 U/kg (314 ± 31 s) for rivaroxaban and 130 U/kg (317 ± 39 s) for apixaban. The NOAC groups required significantly larger doses of total heparin than the warfarin group. CONCLUSION: The baseline ACTs differed among the three NOAC groups. The results of the comparison with warfarin (the control) indicated that dosages of 120 or 130 U/kg for dabigatran, and 130 U/kg for rivaroxaban and apixaban, were adequate initial heparin dosages.