MMP9 and atrial fibrillation: The AUC values of AF IL-8, lipocalin-2, MMP-9, and S100 A8/A9 for the prediction of SPTD within 7 days after sampling were 0.737, 0.717, 0.716, and 0.689, respectively (S4 Table and S1 Fig) and were not significantly different from each other (all variables: P = 0.28–0.73).