MMP1 and atrial fibrillation: As an assessment of collagen turnover, ratios CITP/MMP1 did not present significant difference between stages of AF and the control group (ParAF:0.04 ± 0.02, PerAF: 0.043 ± 0.03, LS PerAF: 0.06 ± 0.04, and control: 0.05 ± 0.05; p = 0.07), as illustrated in Figure 5.