Results
After filtering out duplicate studies, our search strategy yielded 493 articles. After screening the abstracts, 458 studies that were case reports, case series, review articles, in vitro studies, animal studies, or interventional studies were eliminated from the study. The full text of 35 studies was reviewed. The remaining 20 studies were later excluded due to lack of a target population or failure to report outcomes of interest. As a result, the final analysis included 15 observational cohort studies [7-21] with 772 individuals with HFrEF who underwent LBBAP implantation. The included articles were classified into 2 categories: patients with PICM (4 articles, 62 patients)[7-10] and patients without PICM (11 articles, 710 patients) [11-21] . Figure 1 shows the literature review’s inclusion and exclusion process. Tables 1 and 2 show the characteristics and quality assessment of the included studies.