MMP9 and atrial fibrillation: Another study has confirmed that [20] MIP-1α can induce monocytes to produce matrix metalloproteinase 9 and TGF-β expression, while MMP-9 and TGF-β accelerate the progression of atrial fibrillation by increasing the degree of atrial fibrosis and participate in the left atrial remodeling in atrial fibrillation patients.