Impact of ambulatory ECG monitoring duration on precision of AI-based AF burden estimation

Abstract Background Atrial fibrillation (AF) burden has emerged as a prognostic and therapeutic target in patients with paroxysmal AF. Studies have shown that longer ECG monitoring improves AF detection and precision of AF burden estimation [1, 2]. However, majority of these studies relied on simulated ambulatory ECG (AECG) strategies rather than observed recordings. There is limited real-world evidence for how monitoring duration impacts AF detection and burden estimation. We analysed 7-day AECG recordings to estimate detection sensitivity and burden accuracy by monitoring duration. Methods We retrospectively screened 1,886 ambulatory ECG (AECG) recordings of ≥7-day duration collected between 2020 and 2025. To limit bias stemming from hardware, electrode choice, or clinical workflows, we selected six centres in Switzerland, Denmark, and Greece. AECG inclusion criteria were adults with an AI-derived 7-day AF burden >0% and