Key result
Congenital long QT syndrome in a nationwide paediatric cohort was associated with a 3.8% rate of major arrhythmic events over 6 years, predominantly in those with high-risk genotypes or QTc ≥550 ms.
Why the study?
Genotype and QTc duration modulate major arrhythmic event risk in congenital long QT syndrome, but contemporary paediatric outcome data remain limited.
Cohort (n=371)
Yes
In a nationwide paediatric LQTS cohort, major arrhythmic events were rare (3.8% over 6 years) and primarily occurred in children with malignant genotypes, markedly prolonged QTc, or very early presentation.
Supports genotype- and QTc-guided risk stratification in paediatric LQTS; leaves open prospective trials to refine therapies.
BACKGROUND AND AIMS: Congenital long QT syndrome (LQTS) is a heterogeneous disorder in which genotype and QTc duration modulate the risk of major arrhythmic events (MAEs), but contemporary paediatric outcome data remain limited. This study aimed to characterize clinical features, management strategies, and predictors of MAEs in a nationwide paediatric LQTS cohort. METHODS: This retrospective multicentre study analysed children (<18 years) diagnosed with LQTS across 30 tertiary centres (2004-24) using 2022 European Society of Cardiology criteria. MAEs were defined as sudden cardiac death, aborted cardiac arrest, or appropriate implantable cardioverter-defibrillator (ICD) therapy. RESULTS: The cohort included 371 children (58% male; median diagnosis age 6.0 years; interquartile range .25-11 years). Pathogenic/likely pathogenic variants were identified in 86.5%, mainly in KCNQ1, KCNH2, or SCN5A, while 5.7% harboured high-risk genotypes (Jervell-Lange-Nielsen, calmodulinopathies, CACNA1C/Timothy). Beta-blockers were prescribed in 92.4%. Over a median 6-year follow-up, 14 children (3.8%) experienced MAEs, which occurred predominantly in those with high-risk genotypes, QTc ≥550 ms or very early presentation. MAEs were rare in LQT1-3 with QTc <500 ms. Foetal/neonatal bradycardia (5.1%) correlated with high-risk genotypes and adverse outcomes. ICDs were implanted in 33 children (8.9%); 10 (30%) received appropriate therapies, and 8 (24%) experienced complications. Left cardiac sympathetic denervation was performed in 33 (8.9%), mainly high-risk patients, and was associated with >80% arrhythmia-free survival without major complications. CONCLUSIONS: In this nationwide paediatric LQTS cohort, MAEs were uncommon and clustered in children with malignant genotypes, markedly prolonged QTc and very early presentation, particularly foetal or neonatal bradycardia. These data support the current genotype and QTc-guided management strategy, with beta-blockers as the cornerstone therapy and selective use of left cardiac sympathetic denervation and ICDs in high-risk profiles.
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Perín et al. (2026) conducted a cohort in Congenital long QT syndrome (LQTS) (n=371). Congenital long QT syndrome was evaluated on Major arrhythmic events (sudden cardiac death, aborted cardiac arrest, or appropriate ICD therapy). Congenital long QT syndrome in a nationwide paediatric cohort was associated with a 3.8% rate of major arrhythmic events over 6 years, predominantly in those with high-risk genotypes or QTc ≥550 ms.
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