Digital recruitment and prevalence of screen-detected atrial fibrillation in nationwide patch-based ECG screening: the NORSCREEN randomized clinical trial.

Conventional screening modalities for atrial fibrillation (AF) are often constrained by considerable resource and logistical demands. The randomized controlled NORwegian atrial fibrillation self-SCREENing (NORSCREEN) trial employs a fully digital approach to recruitment and implementation. The aim of this pre-specified analysis was to evaluate the effectiveness of the fully digital recruitment and screening strategy, determine the prevalence of screen-detected AF, and assess initial adherence to therapeutic recommendations. Individuals aged ≥65 years with ≥1 additional risk factor for stroke were digitally recruited from the general Norwegian population and randomized 1:1 to screening or usual care. Exclusion criteria included prior AF, anticoagulation, implantable cardiac electronic devices, or lack of smartphone access. Participants allocated to screening were mailed a patch-based electrocardiogram sensor for site-less continuous monitoring over 7 days. Those with diagnosed AF were advised to contact their general practitioner to initiate appropriate therapy. A total of 551 555 Norwegian residents were digitally invited; of these, 139 596 (25.3%) completed the digital eligibility assessment, 74 956 (53.7%) were eligible, and 50 549 (67.4%) were randomized to screening or usual care. The median age was 75 years (inter-quartile range: 69-78), 23 445 (46.4%) were female, and the mean CHA2DS2-VA risk score was 2.6 ± 0.9. In the screening group, 19 723 (78.1%) completed the study procedures. Previously undiagnosed AF was identified in 382 (1.9%) screened participants, of whom 366 (95.8%) initiated anticoagulation therapy. The NORSCREEN trial demonstrates that fully digital, large-scale, site-less AF screening is feasible and effective in an at-risk population, identifying previously undiagnosed AF in 1.9% of screened individuals and showing high adherence to therapeutic recommendations. NCT05914883.