The Impact of LBBAP vs RVP on the Incidence of New-onset 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.