NPPB and atrial flutter: The corrected QT (QTc) interval, QT dispersion, B-type natriuretic peptide (BNP) levels, left ventricular ejection fraction (LVEF), serum creatinine, serum potassium, New York Heart Association (NYHA) classification, Borg dyspnea score, lower-limb edema resolution, systolic/diastolic blood pressure (SBP/DBP), heart rate (HR), incidence of ventricular arrhythmia (VA) and atrial flutter/fibrillation (AFL/AF), and cardiovascular and all-cause mortality were evaluated.