title: Automated external defibrillator rescues among children with diagnosed and treated long QT syndrome.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Kavitha N
authors.initials: KN
authors.lastname: Pundi
authors.affiliation: Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota.
authors.forename: J Martijn
authors.initials: JM
authors.lastname: Bos
authors.affiliation: Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Cannon
authors.affiliation: Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota. Electronic address: ackerman.michael@mayo.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ackerman
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D047548:Defibrillators / Q000706:statistics & numerical data; D004554:Electric Countershock / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D008133:Long QT Syndrome / Q000175:diagnosis / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D008297:Male; D008499:Medical Records; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000628:therapy*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology
keywords: Automated external defibrillator; Long QT syndrome; Out-of-hospital cardiac arrest; Sudden cardiac death; Ventricular fibrillation