Except for tumor necrosis factor-α, interleukin-6, and hypersensitive C-reactive protein, studies showed that galectin 3, matrix metalloproteinase 9, lipoprotein 2, and N-type pro-peptide type III collagen were also involved in the process of AF (Girmatsion et al., 2009). Here, MMP9 is linked to atrial fibrillation.