Since previous studies showed that decreased KCNN3 expression levels were associated with AF [18], our results indicated that mmu_circ_0005019 might inhibit electrical remodeling in vitro, which was consistent with the role mmu_circ_0005019 played in regulating Kcnd1, Kcnd3 and Scn5a. Here, KCND3 is linked to atrial fibrillation.