Multicenter analysis of device-detected atrial fibrillation burden reduction after antiarrhythmic drug initiation

Background There are limited data on changes in atrial fibrillation (AF) burden after antiarrhythmic drug (AAD) initiation. Objectives To quantify AF burden after AAD initiation in patients with cardiac implantable electronic devices (CIEDs). Methods We conducted a retrospective study of all CIED patients from two academic hospitals with new AAD initiation between 4/2018-3/2022. AF burden was quantified in CIED patients at up to 6 months pre- and 12 months post-AAD initiation. Results There were 128 patients (73.6±12.2 years, 61% male) included in analysis. Average time to the first AF quantification post-AAD initiation was 5.0±6.8 months, and 98 patients had >1 post-AAD AF measurement. There was a significant reduction in AF burden at both the first and final interrogations post-AAD initiation compared to pre-AAD AF burden (pre 5.9% [IQR 1.3-29.7%], first post 0.2% [IQR 0-2.9%], final 0.1% [IQR 0-1.5%]). The median AF burden reduction was 90.5% [IQR 2.7-100%] at the first interrogation and 97.4% [IQR 35.7-100%] at the final interrogation. A significant reduction in AF burden was seen at both timepoints in subgroups prescribed amiodarone and non-amiodarone AADs as well as those with high (≥90%) and low (≤20%) baseline AF burden (p-value for all 30 seconds after AAD initiation, median reduction in AF burden was 72.1% [IQR 5.3-96.9%] at the final interrogation. Conclusion There was a median 97.4% [IQR 35.7-100%] reduction in AF burden following AAD initiation in CIED patients through the final interrogation. Results are consistent in subgroups of AAD type and baseline AF burden.