4.3 Limitations
This analysis has several limitations. First, there are currently no
randomized controlled trials for LBBAP targeting HFmrEF; therefore, all
studies included in this meta-analysis were retrospective and
observational. Second, the sample size was small, with 16 centers and
211 patients (207 patients with LVEF followed-up before and after LBBAP,
42 patients with QRS duration followed-up before and after LBBAP)
included in the analysis. Third, there was no long-term follow-up data.
Fourth, in all studies included in the analysis, the pacing lead used
for the procedure was a lumenless lead; therefore, there were no results
for stylet-driven leads. Finally, only one study reported clinical
outcomes including HF hospitalization and mortality. Thus, large-scale
randomized controlled trials with long-term observations are needed.