APOA1 and atrial fibrillation: Although there was large inter-individual variability in AF IL-6 concentrations, higher AF apoA-II concentrations correlated with higher AF IL-6 levels (Pearson’s r = 0.25, P = 0.007), while there was no correlation between AF apoA-I and AF IL-6 (Pearson’s r = 0.07, P = 0.48) (Fig. 3A,B).