Differences in activated clotting time and initial heparin dosage during atrial fibrillation ablation for patients with edoxaban compared with warfarin.

Background: Different target activated clotting times (ACTs) during atrial fibrillation (AF) ablation have been proposed. Moreover, relationships between initial bolus dose of heparin at the start of AF ablation in patients receiving edoxaban anticoagulation therapy and ACT are unclear.

Methods: Patients who received anticoagulation with uninterrupted warfarin (control; n = 120) or interrupted edoxaban (n = 120) on the morning of day of ablation were studied. An initial dose of 100 U/kg heparin was administered as a reliable control for warfarin. Initial heparin doses of 120, 130, 140, or 150 U/kg were randomly administered to the edoxaban group.

Results: Edoxaban group showed shorter baseline ACT before the procedure (130 ± 16 seconds) than the warfarin group (152 ± 26 seconds, P < 0.0001). In the warfarin group, 100 U/kg heparin showed 361 ± 48 seconds 15-minute ACT. In the edoxaban group, an increase in initial dose induced prolongation of 15-minute ACT (i.e., 15-minute ACTs of 293 ± 56, 306 ± 39, 311 ± 45, and 319 ± 45 seconds for 120, 130, 140, and 150 U/kg initial doses, respectively). The total heparin required during the procedure was higher in the edoxaban group than in the warfarin group (109 ± 37 vs. 77 ± 21 U/kg/h, P < 0.0001). The 120-150 U/kg dose of heparin in edoxaban group did not cause thromboembolic or major bleeding complications.

Conclusion: Edoxaban interrupted on the day of ablation showed a shorter baseline ACT than uninterrupted warfarin. Edoxaban required a higher initial heparin dose to achieve a similar 15-minute ACT to warfarin. These results are useful for determining the initial heparin dose required to achieve variable target ACTs.