This study probed the effect of TLR4 on atrial fibrosis and susceptibility to AF in SHRs and explored a possible mechanism, showing that downregulation of TLR4 inhibits activation of NLRP3 inflammasome, resulting in decreased levels of IL-1β, IL-18, and TGF-β, and alleviating atrial fibrosis and susceptibility to AF in SHR (Figure 9). Here, TLR4 is linked to atrial fibrillation.