Impact of Left Bundle Branch Area Pacing vs. Right Ventricular Pacing in Atrioventricular Block (LEAP-Block)

LEAP-BLOCK is a prospective, multi-center, randomized controlled trial that is designed to determine whether left bundle branch area pacing (LBBAP) may reduce the risk of RV ventricular pacing induced cardiac dysfunction as compared with traditional RV pacing (RVP) in patients with atrioventricular (AV) block and normal LV function (LVEF≥50%) who require high percent of ventricular pacing. The primary aim of this trial is to compare the time to first event (composite of all-cause mortality and newly heart failure hospitalization and device upgrade due to heart failure) between LBBAP and RVP group in patients with AV block. Patients with AV block and normal LV function who require high burden of ventricular pacing (expected >40%) will be randomized to LBBAP or RVP group for therapy. Patients will be followed at least every 3 months for clinical status and every 6 months for echocardiographic evaluation until the study closure.

Inclusion criteria

• a. Adult patients aged 18-90;
• b. 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 ≥ 250ms;
• c. The subject is able to receive a pectoral implant;
• d. The subject is willing and able to comply with the protocol;
• e. The subject is expected to remain available for follow-up visits at the study centers.
• f. Subject or authorized legal guardian or representative has signed and dated the study Subject Informed Consent

Exclusion criteria

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