In IAI cases (MMP-8 > 41.5 ng/mL with MIAC) AF-CRP correlated with MMP-8 (rs = 0.501, p = 0.008), MMP-9 (rs = 0.493, p = 0.044), MPO (rs = 0.645, p < 0.001), IL-6 (rs = 0.473, p = 0.013), and MMP-8/TIMP-1 molar ratio (rs = 0.556, p = 0.003). The gene discussed is MMP9; the disease is atrial fibrillation.