Automated external defibrillator rescues among children with diagnosed and treated long QT syndrome

Background Long QT syndrome (LQTS) is a potentially lethal yet highly treatable cardiac channelopathy. A comprehensive LQTS-directed treatment program often includes an automated external defibrillator (AED). Objective The purpose of this study was to determine the incidence of AED rescues among children evaluated, risk-stratified, and treated in an LQTS specialty center. Methods We performed a retrospective review of the electronic medical records to identify 1665 patients evaluated in our Genetic Heart Rhythm Clinic (1999-2013). Subset analysis was performed on 291 children managed without an implantable cardioverter-defibrillator (ICD). Results The average age at diagnosis was 8.3 ± 5.7 years with an average. QTc of 463 ± 40 ms (17% ≥500 ms). The represented LQTS genotypes included type 1 (LQT1) in 52%, type 2 (LQT2) in 35%, and type 3 (LQT3) in 7%. During follow-up, 3 of 291 children (1%) had a cardiac arrest with an appropriate AED rescue (2/51 symptomatic, 1/240 asymptomatic). The first AED rescue occurred during exercise in a symptomatic 3-year-old boy with compound LQT1 treated with beta-blocker and videoscopic left cardiac sympathetic denervation (LCSD). The second AED rescue occurred in a remotely symptomatic 14-year-old boy with high-risk LQT2 (QTc >550 ms) on a beta-blocker who previously declined a prophylactic ICD. The third AED rescue involved an asymptomatic 17-year-old girl with LQT3 on mexiletine who collapsed in school. Conclusion An AED should seldom be necessary in an appropriately treated child with LQTS. Nevertheless, despite only 3 AED rescues in more than 1700 patient-years, an AED can be a lifesaving and cost-effective part of an LQTS patient's comprehensive sudden death prevention program.