Key result
SCN5A-positive early repolarization syndrome patients exhibit ~24 ms shorter QRS duration than Brugada syndrome patients.
Why the study?
ERS and BrS both involve SCN5A mutations, but potential distinct ECG differences between SCN5A-positive patients with these syndromes remained to be investigated.
Do electrocardiographic features differ between SCN5A mutation-positive patients with early repolarization syndrome versus Brugada syndrome?
Meta-Analysis (n=2,104)
Do electrocardiographic features differ between SCN5A mutation-positive patients with early repolarization syndrome versus Brugada syndrome?
SCN5A mutation-positive patients with Brugada syndrome exhibit prolonged QRS indicating conduction abnormalities, whereas those with early repolarization syndrome show normal QRS duration.
SCN5A ERS patients lack QRS prolongation of Brugada; extends ECG phenotyping of channelopathies but observational data leave practice implications open.
Early repolarization syndrome (ERS) and Brugada syndrome (BrS) are both J-wave syndromes. Both can involve mutations in the SCN5A gene but may exhibit distinct electrocardiographic (ECG) differences. The aim of this systematic review and meta-analysis is to investigate possible differences in ECG markers between SCN5A-positive patients with ERS and BrS. PubMed and Embase were searched from their inception to 20 October 2021 for human studies containing the search terms “SCN5A” and “variant” and “early repolarization” or “Brugada”, with no language restrictions. Continuous variables were expressed as mean±standard deviation. PR interval, QRS duration, QTc and heart rate from the included studies were pooled to calculate a mean for each variable amongst BrS and ERS patients. A two-tailed Student’s t test was then performed to for comparisons. A total of 328 studies were identified. After full-text screening, 12 studies met our inclusion criteria and were included in this present study. One hundred and four ERS patients (mean age 30.86±14.45) and 2000 BrS patients (mean age 36.17±11.39) were studied. Our meta-analysis found that ERS patients had shorter QRS duration (90.40±9.97 vs. 114.79±20.10, P = 0.0001) and shorter corrected QT intervals (QTc) with borderline significance (393.63±40.04 vs. 416.82±37.43, P = 0.052). By contrast, no significant differences in baseline heart rate (65.15±18.78 vs. 76.06±18.78, P = 0.068) or PR intervals (197.40±34.69 vs. 191.88±35.08, P = 0.621) were observed between ERS and BrS patients. BrS patients with positive SCN5A mutations exhibited prolonged QRS, indicating conduction abnormalities, whereas ERS patients with positive SCN5A mutations showed normal QRS. By contrast, whilst QTc intervals were longer in BrS than in ERS SCN5A positive patients, they were within normal limits. Further studies are needed to examine the implications of these findings for arrhythmic risk stratification.
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Radford et al. (2022) conducted a meta-analysis in SCN5A mutation-positive Brugada and early repolarization syndromes (n=2,104). Early repolarization syndrome (ERS) vs. Brugada syndrome (BrS) was evaluated on QRS duration (p=0.0001). SCN5A mutation-positive patients with early repolarization syndrome had significantly shorter QRS duration compared to those with Brugada syndrome (90.40 vs. 114.79, P=0.0001).
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