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Background: A rare gene variant in SCN5A can be found in approximately 20%-25% of patients with Brugada syndrome (BrS)., Objective: The aim of this systematic review and meta-analysis was to evaluate the differences in clinical characteristics of BrS patients with and without SCN5A rare variants and the prognostic role of SCN5A for ventricular arrhythmias in BrS., Methods: PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched from inception to January 2024 to identify all relevant studies. Studies were analyzed if they included patients diagnosed with BrS in whom genetic testing for SCN5A variants was performed and arrhythmic outcomes were reported., Results: A total of 17 studies with 3568 BrS patients, of whom 3030 underwent genetic testing for SCN5A variants, fulfilled the eligibility criteria and were included. Compared with SCN5A- patients, SCN5A+ BrS patients more frequently had spontaneous type 1 electrocardiogram, history of syncope, and documented arrhythmias. Furthermore, higher PQ and QRS intervals in SCN5A+ BrS patients compared with SCN5A- have been found. The pooled analysis demonstrated a significant association between the presence of SCN5A rare variants in BrS patients and the risk of major arrhythmic events, with a pooled odds ratio of 2.14 (95% confidence interval, 1.53-2.99; I 2 = 29%)., Conclusion: SCN5A+ BrS patients showed a worse clinical phenotype compared with SCN5A-. The pooled analysis demonstrated a significant association between SCN5A+ mutation status and the risk of major arrhythmic events in BrS patients., Competing Interests: Disclosures A.S. received research grants from Daiichi Sankyo and Bayer and has received speaker fees from Menarini and Bayer. M.L.M. is a consultant for AtriCure. P.B. received compensation for teaching purposes from Biotronik. G.C. received compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik, Boston Scientific, and Acutus Medical. C.dA. receives research grants on behalf of the center from Biotronik, Medtronic, Abbott, LivaNova, Boston Scientific, AtriCure, Philips, and Acutus; and received compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik, LivaNova, Boston Scientific, AtriCure, and Acutus Medical Daiichi Sankyo. The remaining authors have nothing to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Disclosures A.So. received research grants from Daiichi-Sankyo and Bayer; he has received speaker fees from Menarini and Bayer. M.L.M. is a consultant for AtriCure. A.S. is a consultant for Biosense Webster and Medtronic and received speaker fees from Biosense Webster, Biotronik, Pfizer, and MicroPort. G.C. received compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik. and Boston Scientific. C.d.A. receives research grants on behalf of the center from Biotronik, Medtronic, Abbott, MicroPort, Boston Scientific. and AtriCure; and received compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik, MicroPort, Boston Scientific, AtriCure, and Daiichi Sankyo. The remaining authors have no conflicts of interest to disclose.

Background: Brugada syndrome (BrS) is caused by mutations in SCN5A gene in 15%-20% of cases. Previous studies showed worse prognosis in SCN5A mutation carriers (SCN5A+). To date, there are no data on genotype-phenotype correlation with electrocardiographic (ECG) imaging (ECGI) and high-density epicardial electroanatomic map., Objective: This study aimed to correlate SCN5A mutation with substrate severity in BrS assessed by ECGI and high-density electroanatomic map., Methods: All consecutive BrS patients undergoing ECGI and high-density epicardial electroanatomic map with HD Grid Mapping Catheter were retrospectively analyzed. On ECGI, the following parameters were analyzed before and after ajmaline administration: right ventricular outflow tract (RVOT) activation time (RVOT-AT) and RVOT recovery time (RVOT-RT). On electroanatomic map, the parameters analyzed before and after ajmaline were high-frequency potential activation time (HFPat), high-frequency potential duration (HFPd), high-frequency potential amplitude (HFPa), low-frequency potential activation time (LFPat), low-frequency potential duration (LFPd), and low-frequency potential amplitude (LFPa)., Results: Thirty-nine BrS patients with ECGI were included. Eight patients (20.5%) were SCN5A+. At baseline ECGI map, mean RVOT-RT was longer in SCN5A+ (P = .024). After ajmaline administration, SCN5A+ patients showed longer RVOT-AT (125.6 vs 100.8 ms; P = .045) and longer RVOT-RT (426.4 vs 397 ms; P = .033). After ajmaline administration, SCN5A+ showed longer HFPat (164.1 vs 119.5 ms; P = .041); longer LFPat (272.7 vs 200.5 ms; P = .018); and longer LFPd (211.9 vs 151.2 ms; P = .033)., Conclusion: In BrS, SCN5A+ patients compared with SCN5A- patients exhibit marked depolarization and repolarization abnormalities as assessed by ECGI and epicardial high-density electroanatomic map., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: The pathogenesis of Brugada syndrome (BrS) and consequently of abnormal electrograms (aEGMs) found in the epicardium of the right ventricular outflow tract (RVOT-EPI) is controversial., Objective: The purpose of this study was to analyze aEGM from high-density RVOT-EPI electroanatomic mapping (EAM)., Methods: All patients undergoing RVOT-EPI EAM with the HD-Grid catheter for BrS were retrospectively included. Maps were acquired before and after ajmaline, and all patients had concomitant noninvasive electrocardiographic imaging with annotation of RVOT-EPI latest activation time (RVOTat). High-frequency potentials (HFPs) were defined as ventricular potentials occurring during or after the far-field ventricular EGM showing a local activation time (HFPat). Low-frequency potentials (LFPs) were defined as aEGMs occurring after near-field ventricular activation showing fractionation or delayed components. Their activation time from surface ECG was defined as LFPat., Results: Fifteen consecutive patients were included in the study. At EAM before ajmaline, 7 patients (46.7%) showed LFPs. All patients showed HFPs before and after ajmaline and LFPs after ajmaline. Mean HFPat (134.4 vs 65.3 ms, P <.001), mean LFPat (224.6 vs 113.6 ms, P <.001), and mean RVOTat (124.8 vs 55.9 ms, P <.001) increased after ajmaline. RVOTat correlated with HFPat before (ρ = 0.76) and after ajmaline (ρ = 0.82), while RVOTat was shorter than LFPat before (P <.001) and after ajmaline (P <.001). BrS patients with history of aborted sudden cardiac death had longer aEGMs after ajmaline., Conclusion: Two different types of aEGMs are described from BrS high-density epicardial mapping. This might correlate with depolarization and repolarization abnormalities., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)