Objective To explore the clinical efficacy of right ventricular outflow tract (RVOT) or right ventricular apical (RVA) pacing combined with metoprolol on patients with atrial fibrillation of slow ventricular rate complicated with heart failure. Methods The clinical data of 96 patients with atrial fibrillation of slow ventricular rate complicated with heart failure were retrospectively analyzed. All patients were given permanent pacemaker implantation combined with postoperative oral administration of metoprolol, and they were divided into RVOT group (n=57) and RVA group (n=39) according to implantation site of ventricular electrode. The left ventricular structures ［left ventricular enddiastolic diameter (LVEDd), left ventricular endsystolic diameter (LVESd)］, left ventricular function［left ventricular ejection fraction (LVEF), myocardial performance (Tei) index］, electrocardiogram (ECG) parameters (QRS wave duration, P wave dispersion) and life activity ability ［6min walking distance (6MWD), Minnesota Living with Heart Failure Questionnaire (MLHFQ)］ were compared between the two groups before operation and at 1 year after operation. The pacing program control parameters (pacing threshold, electrode impedance) were compared between the two groups immediately during operation and at 1 year after operation. Results At 1 year after operation, there were no significant changes in the LVEDd, LVESd, LVEF, Tei index, QRS wave duration and P wave dispersion in the two groups comparedwith those before operation (P＞0.05), and the LVEDd, LVESd, Tei index, QRS wave duration and P wave dispersion in RVOT group were significantly lower than those in RVA group (P＜0.01) while the LVEF level was significantly higher than that in RVA group (P＜0.01). Immediately during operation, the pacing threshold in RVOT group was significantly higher than that in RVA group while the electrode impedance was significantly lower than that in RVA group (P＜0.05). At 1 year after operation, the pacing threshold and electrode impedance in the two groups were significantly decreased compared with those before operation (P＜0.01), but there were no significant differences between the two groups (P＞0.05). Conclusion RVOT pacing can provide more coordinated ventricular contraction rhythm than RVA pacing in patients with atrial fibrillation of slow ventricular rate and heart failure. Combined with metoprolol, it can effectively prevent left ventricular remodeling, and the therapy has good safety and it is beneficial to the prognosis and rehabilitation of patients.