Differences in intraprocedural ACTs with standardized heparin dosing during catheter ablation for atrial fibrillation in patients treated with dabigatran vs. patients on uninterrupted warfarin.

Purpose: Effective intraprocedural anticoagulation for catheter ablation for atrial fibrillation is critical to minimize the risk of cerebral thromboembolism. The effect of dabigatran on anticoagulation with heparin during the procedure is unknown. This study compares heparin anticoagulation in patients treated with dabigatran vs. patients on uninterrupted warfarin.

Methods: Seventy-six consecutive patients (24 dabigatran and 52 warfarin) subjected to a standard intraprocedural heparin protocol were included. Heparin administration and rapidity and degree of anticoagulation were compared between the groups.

Results: Despite greater administration of heparin (52.5 ± 22.0 vs. 33.2 ± 10.1 units kg(-1) h(-1); p < 0.001), the mean (320.3 ± 19.5 s) and peak (358.8 ± 28.6 s) activated clotting time (ACT) for the dabigatran group were significantly lower than for the warfarin group (mean, 362.9 ± 35.9 and peak, 410.4 ± 49.7; p < 0.001). The time from initial heparin bolus to first ACT of ≥300 s in the dabigatran group was more than twice that observed in the warfarin group (45.0 ± 30.4 vs. 20.9 ± 14.5 min; p < 0.001). The time to first ACT of ≥350 s was similarly prolonged (109.1 ± 60.0 vs. 55.2 ± 51.1 min; p < 0.001) in the dabigatran group, with eight patients (33 %) failing to reach this target. Outcome differences persisted following analysis using linear models and Cox proportional hazard regression with adjustment for propensity scores.

Conclusion: A standard intraprocedural heparin protocol results in delayed and lower levels of anticoagulation as measured by the ACT for patients treated with dabigatran compared with those on uninterrupted warfarin.