The mRNA expression levels of RANKL in both AF and NP cells were significantly upregulated by IL-1β (1.0 ng/mL) (relative expression (vs. control): AF 6.68 ± 1.41; NP 5.80 ± 1.04; p < 0.01, respectively), and by IL-1β (10 ng/mL) (relative expression (vs. control): AF 6.26 ± 1.00; NP 8.10 ± 1.02; p < 0.01, respectively) (Fig. 3c, d). Here, IL1B is linked to atrial fibrillation.