Left bundle branch area pacing for heart failure patients requiring cardiac resynchronization therapy: a meta-analysis

Background: Left bundle area branch pacing (LBBP) is a novel conduction system pacing method to achieve effective physiological pacing and an alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) for patients with heart failure and reduced ejection fraction (HFrEF). Objective: To review current data comparing BVP and LBBP in patients with HFrEF and indication CRT. Methods: We searched PubMed/Medline, Web of Science, and Cochrane Library from the inception of the database to November 2022. All studies that compared LBBP with BVP in patients with HFrEF and indications of CRT were included. Two reviewers performed the study selection, data abstraction, and risk of bias assessment. We calculated risk ratios with the Mantel-Haenszel method and mean difference with inverse variance using random effect models. We assessed heterogeneity using the I 2 index, with I 2 > 50% indicating significant heterogeneity. Results: Ten studies (9 observational studies and 1 randomized controlled trial; 616 patients; 15 centers) published between 2020 and 2022 were included. We observed a shorter fluoroscopy time [mean difference (MD) 9.68, 95% CI 4.49-14.87, I 2 =95%, P<0.01, minutes] as well as a shorter procedure time (MD 33.68, 95% CI 17.80-49.55, I 2 =73%, P<0.01, minutes) during implantation of LBBP CRT compared to conventional BVP CRT. LBBP was shown to have a greater reduction in QRSd (MD 25.13, 95%CI 20.06-30.20, I 2 = 51%, P<0.01, milliseconds) a greater left ventricular ejection fraction (LVEF) improvement (MD 5.80, 95% CI 4.81-6.78, I 2 =0%, P<0.01, percentage) and a greater ventricular end-diastolic diameter (LVEDD) reduction (MD 2.11, 95% CI 0.12-4.10, I 2 =18%, P=0.04, millimeter). There was a greater improvement in New York Heart Association function (NYHA) class with LBBP (MD 0.37, 95% CI 0.05-0.68, I 2 =61%, P=0.02).LBBP was also associated with a lower risk of a composite of heart failure hospitalizations and all-cause mortality [Risk ratio (RR) 0.48, 95% CI 0.25-0.90, I 2 =0%, p=0.02] driven by reduced heart failure hospitalizations (RR 0.39, 95% CI 0.19-0.82, I 2 =0%, p=0.01). However, all-cause mortality rates were low in both groups (1.52% vs. 1.13%) and similar (RR 0.98, 95%CI 0.21-4.68, I 2 =0%, p=0.87). Conclusion: Compared to BVP, LBBP is associated with, a greater improvement in LV systolic function, and a lower rate of heart failure-related hospitalization. Dedicated randomized controlled trials and larger patient populations are needed to further elucidate the long-term safety and efficacy of LBBP CRT.