In our study, Masson staining showed that the atrial fibrosis in the rats in the Ang-II treatment group was significantly more serious than that in rats in the sham group, and the expression of PDK-4, LDHA, collagen Iα, collagen IIIα and MMP-9 was significantly increased, the susceptibility to AF was increased, and the left atrial function deteriorated. Here, MMP9 is linked to atrial fibrillation.