Individualized Dose–Response Algorithm Versus Weight-Based Heparin Dosing for Intraprocedural Anticoagulation During Atrial Fibrillation Ablation

Abstract Background Effective anticoagulation during atrial fibrillation (AF) ablation is essential to minimise thromboembolic and bleeding complications. Conventional weight-based (WB) unfractionated heparin dosing does not account for interindividual variability in anticoagulation response and may result in suboptimal activated clotting time (ACT) control. Objective To compare an individualized dose–response algorithm (DRA) with WB heparin dosing for achieving and maintaining target intraprocedural anticoagulation during AF ablation. Methods We performed a retrospective single-centre cohort study of 238 consecutive AF ablations (WB n=125; DRA n=113). The primary endpoint was anticoagulation precision, defined as variability in deviation from a target ACT of 350 seconds across four intraprocedural timepoints. Secondary endpoints included the proportion of ACT measurements ≥350 seconds and effect modification by weight. Results A greater proportion of ACT measurements reached ≥350 seconds at all timepoints in the DRA group compared with WB dosing. Anticoagulation precision was improved with the algorithm, reflected by lower variability in deviation from the target ACT, particularly early in the procedure (standard deviation at 40 minutes: 14.3 vs 43.3 seconds, p<0.001). Treatment effect on precision was modified by weight (interaction p=0.027). Among patients <80 kg, deviation from target was reduced by 26.6 seconds at 10 minutes (p<0.001) and 21.1 seconds at 40 minutes (p<0.001). Conclusion Individualised dose–response algorithm–guided heparin dosing improved anticoagulation precision during AF ablation, with significantly lower variability and more consistent target attainment. Benefits were most pronounced early and among lighter patients. Prospective studies are required to determine whether improved anticoagulation control translates into improved clinical outcomes.