Cluster randomised controlled trial of screening for atrial fibrillation in people aged 70 years and over to reduce stroke: protocol for the pilot study for the SAFER trial. - Williams K; Modi RN; Dymond A; Hoare S; Powell A; Burt J; Edwards D; Lund J; Johnson R; Lobban T; Lown M; Sweeting MJ; et al. (BMJ open, 2022)