FNDC5 and atrial fibrillation: Univariate logistic regression showed that atrial fibrillation, CKD stages 1–3, LAVI < 39 mL/m2, E/e` < 17, hs-CRP < 6.1 mg/L, TNF-alpha < 3.7 ng/mL, NT-proBNP < 1540 pmol/mL, sST2 < 31 ng/mL, galectin-3 < 28 ng/mL, and irisin > 10.8 ng/mL were associated with improved LVEF in individuals with HF (Table 3).