This is a single-center, randomized controlled study. The aim of this study is to compare the impact of left bundle branch area pacing versus traditional right ventricular pacing on the incidence of atrial fibrillation in patients with atrioventricular block.

Inclusion Criteria:

• Adult patients aged 18-85;
• AV block patients with ventricular pacing indications and the expected rate of ventricular pacing(VP)> 40%, including (a) third-degree AV block; (b) second degree AV block (type II); (c) intermittent advanced AV block with expected VP>40%; (d) symptomatic first degree AV block and PR interval on ECG > 300ms;
• Signed informed consent;

Exclusion Criteria:

• Baseline echocardiographic assessment of patients with impaired LV function (LVEF<50%);
• Patients with the history of atrial fibrillation;
• Having difficulties in follow-up: Those who cannot accept 2-year follow-up on time due to physical condition or other reasons;
• Pacemaker replacement without new implanted ventricular electrodes;
• Surgery is required within 1 year due to severe structural heart disease;
• Patients with tricuspid mechanical valve replacement, or congenital heart disease (including transposition of the great arteries, or permanent left superior vena cava, etc);
• AV block resulting from: (a) Hypertrophic cardiomyopathy(HCM), (b) ventricular septal defect repair, and those who are unlikely to achieve successful LBBAP procedure.