Our data demonstrated that the expression of two pro-inflammatory cytokines (IL-1β and IL-6 at the transcriptional level) and the extent of inflammatory cell infiltration (F4/80-positive cells), were decreased in cardiac-specific Bhlhe40-knockdown mice with Ang II infusion compare with the control mice with Ang II infusion, suggesting that Bhlhe40 may regulate Ang II-induced AF via regulating atrial inflammation. This evidence concerns the gene IL1B and atrial fibrillation.