5.STUDY LIMITATION
There are several limitations of this meta-analysis. First, the number
of included patients was limited and most of the studies were cohort
studies with inherent limitations that reduced the internal validity
compared to randomized controlled trials. Second, there are limited data
on the effect size of LBBAP on outcomes as the studies included were
observational and did not all have comparative arms. Next, some data,
including pacing pulse width and follow-up time, were variable and
inconsistent, which may influence the study uniformity. In addition,
there was no uniformity at this time in measuring QRS durations with
selective and nonselective LBBAP. Finally, the indications for pacemaker
placement defined by the studies we included were not uniform and were
broad in scope. On the one hand, this demonstrates the great potential
and promise of LBBAP for apply in patients with all types of pacemaker
indications, and on the other hand, it creates an inevitable
heterogeneity in the statistical analysis we perform.