AF cells showed significant increases in MMP-2 (1.28 ± 0.17 relative fluorescent signal, p < 0.0001) and MMP-9 (1.33 ± 0.10 relative fluorescent signal, p < 0.0001) when transfected with miR inhibitors without IL-1β treatment and a similar trend in MMP-3 (2.55 ± 0.78 relative fluorescent signal, p < 0.0001). The gene discussed is MMP9; the disease is atrial fibrillation.