FABP4 and atrial fibrillation: However, FABP4 levels were up‐regulated (1.54 ± 0.01 vs 1.47 ± 0.01, P = .005) (Figure 6B) and PREF1 mRNA expression levels in EAT SVC from AF patients (1.52 ± 0.03 vs 1.44 ± 0.01, P = .020) (Figure 6C).