IL17A and atrial fibrillation: In this study, the proportion of Th17 cells was positively correlated with IL-17, IL-6, and MMP9, indicating that the increase of Th17 cells in the peripheral blood of AF patients can induce the production of inflammatory cytokines IL-17, IL-6, and MMP9, which in turn affects AF, and also indicating that Th17 cells can be used as one of the risk factors for AF.