BACKGROUND: Temporal development of new-onset atrial fibrillation (NOAF) after aortic valve replacement is unclear, and opportunistic screening has limited diagnostic accuracy. This is the first study to investigate the incidence and temporal development of NOAF detected by implantable loop recorder (ILR) in patients with aortic stenosis, randomized to surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR).

METHOD: An ILR was implanted in a subgroup of patients without pre-procedural atrial fibrillation (AF), randomized to SAVR or TAVR in the NOTION trial. Data from the ILR were transmitted in intervals of 2weeks for 12weeks post-procedurally and analyzed.

RESULTS: The study included 25 and 27 patients who underwent SAVR and TAVR, respectively. The cumulative rate of NOAF was 100% and 81.5% for patients undergoing SAVR and TAVR, respectively (P=0.06). TAVR patients without NOAF 6weeks post-procedurally remained free from NOAF. The prevalence of AF after SAVR decreased significantly after 8weeks when compared with the first 2weeks (50.0% vs. 84.0%, respectively; P<0.05). The prevalence of AF after TAVR did not change significantly during follow-up. The median AF burden (percentage of time with AF) was 2.8% and 0.04% during the first 2weeks after SAVR and TAVR, respectively (P=0.01) and it decreased significantly over time after SAVR but not after TAVR.

CONCLUSION: NOAF subsided 6weeks after TAVR. AF prevalence and burden decreased significantly over time after SAVR, but remained stable after TAVR. These findings may be considered for post-procedural anti-coagulation strategy.