NPPB and atrial fibrillation: Atrial natriuretic peptide levels were 75.3 ± 50.0 pg/mL in sinus rhythm patients without S4 and 138.0 ± 16.6 pg/mL in patients with AF; brain natriuretic peptide levels were 85.4 ± 85.5 and 331.9 ± 49.6 pg/mL, respectively.