2.2 Inclusion criteria
The eligibility criteria included the following: (1) Cohort studies (prospective or retrospective) or randomized control trials reporting MAE after the diagnosis of BrS including SCD, sudden cardiac arrest, VF, sustained ventricular tachycardia, and appropriate shock in BrS patients diagnosed from drug challenge test by sodium channel blocker (SCB) and spontaneous Type-1 electrocardiogram (ECG).
(2) Adjusted or unadjusted relative risk, Odds ratio (OR), hazard ratio with 95% confidence interval (CI), or sufficient raw data for the calculation were provided. Patients with spontaneous Type-1 ECG were used as controls.
Study eligibility was independently determined by two investigators (CK and NP) and differences were resolved by mutual consensus. The Newcastle-Ottawa quality assessment scale (NOS) was used to assess each study’s quality in three domains, recruitment and selection of the participants, similarity and comparability between the groups, and ascertainment of the outcome of interest among cohort and case-control studies (7).
2.3 Data extraction A standardized data collection form was used to obtain the following information from each study: title of study, name of first author, year of publication, study design, country of origin, number, gender and age of the participants, Brugada ECG pattern, incidence of MAE, available MAE outcome, follow-up duration, and confounders that were adjusted in the multivariable analysis, if available. Two investigators (JK and PM) independently performed this data extraction process to ensure accurate data extraction. Any data discrepancy was resolved by referring back to the original articles.