title: Implantable cardioverter-defibrillator explantation for overdiagnosed or overtreated congenital long QT syndrome.
abstract: BACKGROUND
  Primary treatment of long QT syndrome (LQTS) currently consists of beta-blocker therapy, although an implantable cardioverter-defibrillator (ICD) is considered for high-risk patients. However, both overdiagnosis and overtreatment must be avoided because their sequelae can be significant.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the prevalence and details of ICD explants in a cohort of patients from a tertiary genetic heart rhythm clinic for a previously rendered diagnosis of LQTS.
  
  
  METHODS
  Overall, 1227 consecutive patients were included in the study. All patients had been referred to the Mayo Clinic for evaluation of possible LQTS and subsequently were either diagnosed with LQTS or dismissed as normal. Further stratification of patients was conducted to assess how many patients had an ICD and how many had a subsequent ICD explant.
  
  
  RESULTS
  In total, 170 patients (14%) had an ICD, including 157 of 670 patients (23%) with confirmed LQTS and 13 of 557 patients (2%) who did not have LQTS. Among these, 12 of 1227 (1%) had the ICD removed: 7 of 157 LQTS patients (4.5%) compared to 5 of 14 non-LQTS patients (36%). Before explant, 5 of 12 patients (42%) experienced inappropriate shocks, ranging from 2 to as many as 54 shocks. In addition, 4 had a device-related infection, and 9 had device malfunction (including lead dysfunction or fracture). None of these patients had a breakthrough cardiac event since removal of their ICD during 5.5 ± 3.5 years of follow-up.
  
  
  CONCLUSIONS
  Implications of overdiagnosis and overtreatment are profound because unnecessary ICD placement can be associated with infection, malfunction, inappropriate shocks, and subsequent anxiety.
authors.affiliation: Mayo Medical School, Mayo Clinic, Rochester, Minnesota.
authors.forename: Prakriti
authors.initials: P
authors.lastname: Gaba
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.
authors.forename: J Martijn
authors.initials: JM
authors.lastname: Bos
authors.affiliation: Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Cannon
authors.affiliation: Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
authors.affiliation: Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.affiliation: Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
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: D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D020878:Device Removal / Q000379:methods*; D004562:Electrocardiography; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000151:congenital / Q000175:diagnosis / Q000628:therapy*; D008297:Male; D000069342:Medical Overuse; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Defibrillation; Explantation; Implantable cardioverter-defibrillator; Inappropriate shock; Long QT syndrome