title: Long QT syndrome in adults.
abstract: OBJECTIVE
  The aims of this study were: 1) to evaluate risk factors influencing the clinical course of mutation-confirmed adult patients with long QT syndrome (LQTS), 2) to study life-threatening cardiac events as a specific end point in adults, and 3) to examine the protective effect of beta-blocker therapy on cardiac events in adult LQTS patients with known cardiac channel mutations.
  
  
  BACKGROUND
  The clinical course and risk factors for cardiac events in genotype-confirmed adult patients with LQTS have not been previously investigated.
  
  
  METHODS
  The clinical characteristics of 812 mutation-confirmed LQTS patients age 18 years or older were studied with both univariate and multivariate analyses to determine the genotype-phenotype factors that influence the clinical course of adult patients with this disorder.
  
  
  RESULTS
  Female gender, corrected QT (QTc) interval, LQT2 genotype, and frequency of cardiac events before age 18 years were associated with increased risk of having any cardiac events between the ages of 18 and 40 years. Female gender, QTc interval > or =500 ms, and interim syncopal events during follow-up after age 18 years were associated with significantly increased risk of life-threatening cardiac events in adulthood. Beta-blockers provided a 60% reduction in risk of any cardiac event and life-threatening events, with somewhat greater effect in higher-risk subjects.
  
  
  CONCLUSIONS
  The severity of LQTS in adulthood can be risk stratified with information regarding genotype, gender, QTc duration, and history of cardiac events. Beta-blockers effectively reduce but do not eliminate the risk of both syncopal and life-threatening cardiac events in adult patients with mutation-confirmed LQTS.
authors.affiliation: Cardiology Unit of the Department of Medicine, University of Rochester Medical Center, Rochester, New York 14642-8653, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sauer
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.forename: Derick R
authors.initials: DR
authors.lastname: Peterson
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Robinson
authors.forename: Ming
authors.initials: M
authors.lastname: Qi
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
authors.forename: Jenny B
authors.initials: JB
authors.lastname: Hobbs
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ackerman
authors.forename: Jesaia
authors.initials: J
authors.lastname: Benhorin
authors.forename: W Jackson
authors.initials: WJ
authors.lastname: Hall
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Kaufman
authors.forename: Emanuela H
authors.initials: EH
authors.lastname: Locati
authors.forename: Carlo
authors.initials: C
authors.lastname: Napolitano
authors.forename: Silvia G
authors.initials: SG
authors.lastname: Priori
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Schwartz
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Towbin
authors.forename: G Michael
authors.initials: GM
authors.lastname: Vincent
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D017677:Age Distribution; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D051657:KCNQ1 Potassium Channel / Q000235:genetics*; D008133:Long QT Syndrome / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality*; D008297:Male; D009154:Mutation; D016016:Proportional Hazards Models; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D016019:Survival Analysis
chemical_list: D000319:Adrenergic beta-Antagonists; D051657:KCNQ1 Potassium Channel