Wearable Smartwatches for Atrial Fibrillation Detection and Burden Estimation After Ablation: Comparison With Continuous Monitoring

Background Wearable ECG-enabled smartwatches have been validated for atrial fibrillation (AF) screening, but their accuracy for monitoring AF recurrence and quantifying AF burden after catheter ablation is uncertain. Objectives To evaluate the simulated performance of three commercial smartwatch algorithms for AF recurrence detection and AF burden estimation compared with implantable cardiac monitors (ICMs). Methods Using continuous ICM data from 346 patients in the CIRCA-DOSE trial, we simulated three smartwatch algorithms, assuming daytime wear (8:00 AM–10:00 PM). We also simulated commonly-used non-invasive intermittent rhythm monitoring strategies. Primary endpoints were sensitivity for arrhythmia recurrence and correlation with ICM-derived AF burden. Analyses were stratified by daily wear time and patient activity. Results AF recurrence occurred in 47.1% of patients. Simulated detection sensitivities were 82.2% (Apple Watch AF Burden), 70.6% (Apple Watch IRN), and 64.4% (Fitbit IHRD), compared with 15.8%–64.6% for simulated intermittent AECG monitors. Wearables outperformed commonly-used Holter/patch monitoring strategies. AF burden correlation with ICM exceeded r = 0.97 for all algorithms. Among missed recurrences, median AF burden was <0.02%. Longer daily wear improved sensitivity (>90% with 24-hour use), whereas patient activity modestly reduced detection. Conclusions Smartwatch-based AF detection algorithms demonstrate strong correlation with ICM-derived AF burden and clinically good sensitivity for recurrence detection, outperforming conventional non-invasive strategies. These findings support the integration of wearables as a scalable alternative for post-ablation rhythm monitoring.