Device-detected Atrial Fibrillation: How Much is Too Much?

Device-detected AF, commonly labelled atrial high-rate episodes or subclinical AF (SCAF), creates a dilemma over anticoagulation: absolute stroke risk will be lowered, yet oral anticoagulation (OAC) carries a real risk of major bleeding. The author argues that searching for a universal episode-duration threshold is not the answer. Analyses of trial results show that baseline SCAF frequency and longest episode duration do not reliably identify a high-risk subgroup nor consistently justify escalation to anticoagulation treatment. Duration-only thresholding is therefore an unstable primary decision-making tool. A practical alternative is proposed: phenotype-led anticoagulation with a burden-led workflow. Phenotypes, especially vascular disease and absolute risk, drive whether OAC is plausibly beneficial; burden determines urgency, monitoring intensity and the need for escalation. This framework primarily addresses SCAF episodes below 24 hours, where clinical uncertainty is greatest and randomised evidence is most directly applicable. It is operationalised as a device-clinic pathway with electrogram adjudication as an entry criterion, burden classes for triage, and phenotype classes for OAC selection, using atrial substrate markers only as tiebreakers in borderline cases.