A study in humans identified the mir-6877-5p as a differentially expressed microRNA in serum, where it was downregulated in the control group but upregulated in patients with atrial fibrillation across baseline, 12-month, and 24-month follow-up periods, as determined by miRNA sequencing and time series analysis [Wang et al. DOI:10.1016/j.hrtlng.2020.03.021].