title: Implantable cardioverter defibrillator treatment in long QT syndrome patients: a national study on adherence to international guidelines.
abstract: OBJECTIVE
  Implantable cardioverter defibrillator (ICD) treatment is effective among long QT syndrome (LQTS) patients at a high risk of sudden cardiac death. Previous studies show that the international guidelines are not always followed, and that risk stratification may be based on genotype rather than individual risk profile. We analysed data from the Swedish ICD & Pacemaker Registry and medical records to examine how international guidelines were followed with regards to phenotype and genotype.
  
  
  RESULTS
  ICD treatment was used in 150 Swedish LQTS patients from 1989-2013. The annual number of implantations increased over the study period. A total of 109 patients were included in the analysis. Most patients (91%) were symptomatic before the implantation. Seventy percent of patients who received ICD treatment met the 2006 Class I or Class IIa recommendations for LQTS treatment. Thirty-one percent of the LQT3 patients received ICD treatment despite being asymptomatic. Among LQT1 patients, 45% received ICD treatment after syncope despite beta-blockers.
  
  
  CONCLUSIONS
  Thirty percent of Swedish LQTS patients with ICD received the treatment without a strong indication based on international guidelines. LQT3 patients were over-represented among asymptomatic patients. Many LQT1 patients received ICD despite the known effect of beta-blockers in this group.
authors.affiliation: a Department of Clinical Sciences, Paediatrics , Umeå University , Umeå , Sweden.
authors.forename: Emilia
authors.initials: E
authors.lastname: Sundström
authors.affiliation: b Department of Public Health and Clinical Medicine , Heart Centre, Umeå University , Umeå , Sweden.
authors.forename: Steen M
authors.initials: SM
authors.lastname: Jensen
authors.affiliation: b Department of Public Health and Clinical Medicine , Heart Centre, Umeå University , Umeå , Sweden.
authors.forename: Ulla-Britt
authors.initials: UB
authors.lastname: Diamant
authors.affiliation: a Department of Clinical Sciences, Paediatrics , Umeå University , Umeå , Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Rydberg
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D017147:Defibrillators, Implantable / Q000592:standards; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation* / Q000592:standards; D005260:Female; D020022:Genetic Predisposition to Disease; D019983:Guideline Adherence / Q000592:standards; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D018579:Patient Selection; D010641:Phenotype; D017410:Practice Guidelines as Topic / Q000592:standards; D010818:Practice Patterns, Physicians' / Q000592:standards; D012042:Registries; D012189:Retrospective Studies; D013548:Sweden; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: Long QT syndrome; aborted cardiac arrest; beta-blocker treatment; guidelines; implantable cardioverter defibrillator; syncope