Apple Watch-Guided Anticoagulation After Atrial Fibrillation Ablation　- The Up to AF Trial

Continuous anticoagulation guided by the CHA₂DS₂-VASc score is standard for atrial fibrillation (AF) but does not reflect real-time AF occurrence. We evaluated an Apple Watch-guided event-triggered anticoagulation strategy that adjusts direct oral anticoagulant (DOAC) use according to smartwatch detection.

This multicenter prospective single-arm study enrolled postablation patients in sinus rhythm who were taking DOACs and had a CHA₂DS₂-VASc score ≤3. Apple Watch monitoring continued for 360 days. If no AF occurred during Days 1-30, anticoagulation was stopped on Day 31; thereafter, Apple Watch notification or electrocardiogram (ECG) evidence of AF prompted DOAC resumption through Day 360. Of 54 enrolled patients enrolled in the study, 50 comprised the analysis population (mean age 63 years; 10% female; median CHA₂DS₂-VASc score 2). Across 15,865 person-days, Apple Watch guidance reduced DOAC exposure by 94.6% compared with continuous anticoagulation. Reductions were similar for patients with CHA₂DS₂-VASc scores of 2-3 and 0-1 (95.0% and 94.0%, respectively; P=0.818). No deaths, strokes, systemic thromboembolic events, or bleeding events were observed. One device malfunction prevented ECG acquisition.

In this cohort, Apple Watch-guided event-triggered anticoagulation markedly reduced DOAC exposure without thromboembolic events. Given the limited sample size and low baseline thromboembolic risk, these safety findings should be interpreted cautiously. Results were similar in the prespecified analysis restricted to patients with CHA₂DS₂-VASc scores of 2-3, the group for whom postablation anticoagulation decisions are most clinically relevant.