Post Hoc Analysis of the LOOP Randomized Clinical Trial Søren Zöga Diederichsen, MD, PhD1; Lucas Yixi Xing, MD1; Diana My Frodi, MD1; Emilie Katrine Kongebro, MD1; Ketil Jørgen Haugan, MD, PhD2; Claus Graff, PhD3; Søren Højberg, MD, PhD4; Derk Krieger, MD, PhD5; Axel Brandes, MD, DMSc6,7,8; Lars Køber, MD, DMSc1,9; Jesper Hastrup Svendsen, MD, DMSc1,9 Article Information JAMA Cardiol. Published online February 15, 2023. doi:10.1001/jamacardio.2022.5526 editorial comment icon Editorial Comment author interview icon Interviews Audio Author Interview (27:12) Prevalence and Prognostic Significance of Bradyarrhythmias in Patients Screened for Atrial Fibrillation vs Usual Care Subscribe to Podcast Key Points Question In a future of increased heart rhythm monitoring, what is the expected prevalence and prognostic significance of incidentally diagnosed bradyarrhythmias? Findings In this post hoc analysis of a randomized clinical trial of persons older than 70 years undergoing implantable loop recorder screening for unknown atrial fibrillation vs usual care, screening was associated with incidental diagnosis of sinus node dysfunction or atrioventricular block in 1 in of 5 persons and increased pacemaker implantations, but there was no change in the risk of syncope or sudden death.