title: QTc dispersion predicts cardiac mortality in the elderly: the Rotterdam Study.
abstract: BACKGROUND
  Increased QTc dispersion has been associated with an increased risk for ventricular arrhythmias and cardiac death in selected patient populations. We examined the association between computerized QTc-dispersion measurements and mortality in a prospective analysis of the population-based Rotterdam Study among men and women aged > or = 55 years.
  
  
  RESULTS
  QTc dispersion was computed with the use of the Modular ECG Analysis System as the difference between the maximum and minimum QTc intervals in 12 and 8 leads (ie, the 6 precordial leads, the shortest extremity lead, and the median of the 5 other extremity leads). After exclusion of those without a digitally stored ECG, the population consisted of 2358 men and 3454 women. During the 3 to 6.5 years (mean, 4 years) of follow-up, 568 subjects (9.8%) died. The degree of QTc dispersion was categorized into tertiles. Data were analyzed using the Cox proportional hazards model, with adjustment for age. For QTc dispersion in 8 leads, those in the highest tertile relative to the lowest tertile had a twofold risk for cardiac death (hazard ratio, 2.5; 95% confidence interval [CI], 1.6 to 4.0) and sudden cardiac death (hazard ratio, 1.9; 95% CI, 1.0 to 3.7) and a 40% increased risk for total mortality (hazard ratio, 1.4; 95% CI, 1.2 to 1.8). Additional adjustment for potential confounders, including history of myocardial infarction, hypertension, and overall QTc, did not materially change the risk estimates. Hazard ratios for QTc dispersion in 12 leads were comparable to those found for QTc dispersion in 8 leads.
  
  
  CONCLUSIONS
  QTc dispersion is an important predictor of cardiac mortality in older men and women.
authors.affiliation: Department of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands. debruyne@epib.fgg.eur.nl
authors.forename: M C
authors.initials: MC
authors.lastname: de Bruyne
authors.forename: A W
authors.initials: AW
authors.lastname: Hoes
authors.forename: J A
authors.initials: JA
authors.lastname: Kors
authors.forename: A
authors.initials: A
authors.lastname: Hofman
authors.forename: J H
authors.initials: JH
authors.lastname: van Bemmel
authors.forename: D E
authors.initials: DE
authors.lastname: Grobbee
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D001145:Arrhythmias, Cardiac / Q000401:mortality / Q000503:physiopathology; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors