This study is a multicenter, prospective, randomized study to assess if cardiac dysfunction patients with LVEF <50% and the estimated ventricular pacing percentage >40% with LBBP have the non-inferior safety and efficacy than CRT on patients' cardiac function and prognosis

Patients who meet the inclusion and exclusion criteria will be enrolled into the study. In the study, patients with cardiac dysfunction who met the enrollment criteria and will agree to participate in this trial will be 1:1 randomized to the LBBP group and the CRT group. Patients who were successfully implanted were enrolled for evaluation and follow-up. The primary end points of the study is the change of LVEF within 12 months post-implant in both LBBP Treatment Group and CRT Treatment Group

Inclusion Criteria:

• Above 18 years old
• Agree to participate in trial and sign informed consent
• NYHA cardiac function class I-III
• LVEF<50%
• Second or complete atrioventricular block with pacing indication or ventricular pacing dependent with ventricular pacing percentage >40%
• Patients who are willing to take the de-novo implant or device replacement or upgrade.

Exclusion Criteria:

• Life expectancy <1 year
• Patients with severe tricuspid valvular disease1 or who have undergone mechanical valve or bioprosthetic valve surgery
• Acute myocardial infarction within 1 month
• Women of childbearing age who are pregnant or becoming pregnant during the study period
• Severe liver and kidney dysfunction2
• Have been enrolled in another clinical studies that may interferes with the current trial objectives
• Evidence of severe pulmonary hypertension (PASP>70mmHg)
• Evidence of hypertrophic cardiomyopathy which shall affect the prognosis of patients.
• The investigator believes that subject's physical condition is not suitable for participation in the trial