3. Results
3.1 Search resultsOur search strategy yielded 815 potentially relevant articles (465 articles from EMBASE and 350 articles from MEDLINE). After the exclusion of duplicated articles, 732 articles underwent title and abstract review. At this stage, 633 articles were excluded as they were not cohort, case-control, or randomized controlled trials, were not conducted in BrS patients or the titles and abstracts were not relevant. This left 99 articles for full-length review. Another 81 studies were excluded as they did not report data regarding SCB use, outcome of interest, or did not provide sufficient data to calculate OR. Therefore, a total of 18 studies were included in this meta-analysis (3, 14-30). Figure 1 outlines the search and literature review process.
3.2 Description of included studies
Eighteen studies from 2006 to 2018 were included in this meta-analysis involving 4,099 Brugada syndrome patients. Seventeen of 18 studies involving 3,596 Brugada syndrome patients reported the incidences of MAE in spontaneous Type-1 and drug challenge induced Type-1 Brugada pattern (3, 14-26, 28-30). Three of eighteen studies involving 776 Brugada syndrome patients reported MAE during drug challenge testing (16, 27, 30). Six of eighteen studies involving 541 Brugada syndrome patients reported symptomatic versus asymptomatic patients who had undergone drug challenge testing (3, 14, 21, 23, 24, 30). Mean follow-up was 4.5 years and 57.6% of Brugada syndrome patients were diagnosed by drug challenge induced Type-1 Brugada pattern. A summary of study characteristics is shown in Table 1.
3.3 Quality assessment of included studiesThe NOS of included studies are described in Supplement Table. The NOS uses a star system (0 to 9) to evaluate included studies on 3 domains: selection, comparability, and outcomes. Higher scores represent a higher study quality.