Left bundle branch area pacing for atrioventricular block and mild to moderately reduced left ventricular systolic function

INTRODUCTION: The clinical efficacy of left bundle branch area pacing (LBBAP) has not been fully elucidated in patients with atrioventricular block and mild to moderately reduced left ventricular ejection fraction (LVEF). This study evaluated the impact of LBBAP on patients with an LVEF of ≤50% and dependent on ventricular pacing. METHODS AND RESULTS: Thirty-seven patients with atrioventricular block underwent successful LBBAP. All patients had a reduced LVEF of 36%-50% and underwent pacemaker implantation. Ventricular pacing was performed using the LBBAP alone throughout the follow-up period. Clinical outcomes, including death from any cause, fatal ventricular arrhythmias, hospitalization for heart failure, and echocardiographic improvements after 1 year, were assessed. Thirty-three (89%) patients were free from the composite endpoint during a median follow-up of 36 months, whereas four patients experienced noncardiovascular deaths or hospitalization for heart failure. No fatal ventricular arrhythmias occurred. LVEF was improved using LBBAP from 42.6 ± 4.7% to 52.1 ± 9.1% (p 50%) was achieved in 64.5% of patients, while in 11 patients LVEF remained stable demonstrating no deterioration (from 42.5 ± 4.7% to 42.4 ± 6.3%). Nonischemic cardiomyopathy (odds ratio, 21.52; 95% confidence interval, 1.96-236.45) and Pre-existing bundle branch block (odds ratio, 11.79; 95% confidence interval, 1.11-125.75) were independent preoperative predictors of LVEF normalization using LBBAP. CONCLUSION: LBBAP significantly improved cardiac systolic dysfunction without causing fatal ventricular arrhythmias. Moreover, LBBAP may provide a promising alternative to biventricular pacing in patients with atrioventricular block and a reduced LVEF of 36%-50%.