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 index, with I
> 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 =95%,
P<0.01, minutes] as well as a shorter procedure time (MD
33.68, 95% CI 17.80-49.55, I =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 = 51%,
P<0.01, milliseconds) a greater left ventricular ejection
fraction (LVEF) improvement (MD 5.80, 95% CI 4.81-6.78, I
=0%, P<0.01, percentage) and a greater
ventricular end-diastolic diameter (LVEDD) reduction (MD 2.11, 95% CI
0.12-4.10, I =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 =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 =0%, p=0.02]
driven by reduced heart failure hospitalizations (RR 0.39, 95% CI
0.19-0.82, I =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 =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.