Abstract 2214: Risk Factors for Aborted Cardiac Arrest or Sudden Cardiac Death in Children with the Congenital Long QT Syndrome
Background: Previous studies evaluating predictors for cardiac events in patients with the congenital long QT syndrome (LQTS) included syncope as the predominant endpoint, whereas data on risk factors for fatal or near fatal events during childhood are limited.
Methods: Cox proportional hazards regression modeling was used to identify risk factors for aborted cardiac arrest (ACA) or LQTS-related death in 3,636 children (ages 1 through 12 years) diagnosed with LQTS by prolonged corrected QT interval (QTc) criteria for age and gender from the International LQTS Registry. The efficacy of β-blocker therapy, analyzed as a time-dependent covariate, for the reduction in the risk of fatal or near-fatal events was assessed within identified risk subgroups of study subjects.
Results: Risk factors independently associated with ACA or death included a maximum QTc interval duration ≥500 msec during follow-up; the occurrence of time-dependent syncope; male gender; and ECG documentation of torsade de pointes during follow-up (Table⇓). β-blocker therapy was associated with a significant reduction in the risk of ACA or death in high-risk patients who experienced syncope during follow-up (HR = 0.44 [95% CI 0.23 – 0.84]; p = 0.01).
Conclusions: Clinical and ECG factors identify LQTS children with increased risk for fatal or near-fatal events. β-blocker therapy is associated with a significant benefit in the high-risk subset.