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Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
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QT interval prolongation and risk for cardiac events in genotyped LQTS-index children

H Wedekind1, D Burde, S Zumhagen

  • 1Department of Cardiology and Angiology, University Hospital of Münster, Münster, Germany. horst.wedekind@marienhospital-hamm.de

European Journal of Pediatrics
|December 23, 2008
PubMed

Insights

Congenital long-QT syndrome (LQTS) in children often presents with severe symptoms like syncope or cardiac arrest. A prolonged QT interval (QTc >500 ms) and prior cardiac events are key predictors of future risk.

Area of Science:

  • Cardiology
  • Genetics
  • Pediatrics

Background:

  • Congenital long-QT syndrome (LQTS) is an inherited cardiac disorder causing repolarization disturbances and life-threatening ventricular tachycardia.
  • Risk factors for LQTS cardiac events include gender, genotype, triggers, and prior events, with gender-related differences noted in children.
  • Early disease onset and lifestyle changes in children necessitate understanding specific risk factors.

Purpose of the Study:

  • To investigate clinical features of genotyped LQTS-index children (age ≤16 years).
  • To determine risk factors for cardiac symptoms and events in this pediatric population.
  • To identify predictors for recurrent cardiac events in children with LQTS.

Main Methods:

  • Analysis of a large, genotyped cohort of LQTS-index children from a single center.
  • Evaluation of clinical presentations, including syncope, aborted cardiac arrest (ACA), and sudden cardiac death (SCD).
  • Statistical analysis to identify risk factors for cardiac events during follow-up, including corrected QT interval (QTc) and prior events.

Main Results:

  • Of 83 children, 89% had LQT1, -2, or -3; 11% had Jervell and Lange-Nielsen syndrome.
  • Symptomatic children (61%) most commonly presented with syncope (49%), ACA (33%), or SCD (18%).
  • During follow-up, 31% developed symptoms; QTc >500 ms (p=0.02), prior syncope (HR 4.05), and ACA (HR 11.7) predicted recurrent events.

Conclusions:

  • LQTS-index children frequently experience severe initial symptoms.
  • A QTc interval >500 ms is a significant predictor of cardiac events.
  • History of syncope or ACA strongly predicts recurrent cardiac events in children with LQTS.

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