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

<h2>Abstract</h2><h3>Background</h3> There are limited data on changes in atrial fibrillation (AF) burden after antiarrhythmic drug (AAD) initiation. <h3>Objectives</h3> To quantify AF burden after AAD initiation in patients with cardiac implantable electronic devices (CIEDs). <h3>Methods</h3> 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. <h3>Results</h3> 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 <0.05). Among patients with AF >30 seconds after AAD initiation, median reduction in AF burden was 72.1% [IQR 5.3-96.9%] at the final interrogation. <h3>Conclusion</h3> 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.