title: The QT interval and risk of incident atrial fibrillation.
abstract: BACKGROUND
  Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine.
  
  
  OBJECTIVE
  To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF.
  
  
  METHODS
  We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The Cardiovascular Health Study (CHS) and Health, Aging, and Body Composition (ABC) study were used for validation. Secondary predictors included QT duration as a continuous variable, a short QT interval, and QT intervals corrected by using other formulas.
  
  
  RESULTS
  Among 14,538 ARIC study participants, a prolonged QT(Fram) predicted a roughly 2-fold increased risk of AF (hazard ratio [HR] 2.05; 95% confidence interval [CI] 1.42-2.96; P < .001). No substantive attenuation was observed after adjustment for age, race, sex, study center, body mass index, hypertension, diabetes, coronary disease, and heart failure. The findings were validated in Cardiovascular Health Study and Health, Aging, and Body Composition study and were similar across various QT correction methods. Also in the ARIC study, each 10-ms increase in QT(Fram) was associated with an increased unadjusted (HR 1.14; 95% CI 1.10-1.17; P < .001) and adjusted (HR 1.11; 95% CI 1.07-1.14; P < .001) risk of AF. Findings regarding a short QT interval were inconsistent across cohorts.
  
  
  CONCLUSIONS
  A prolonged QT interval is associated with an increased risk of incident AF.
authors.affiliation: Electrophysiology Section, Division of Cardiology, University of California, San Francisco, California.
authors.forename: Mala C
authors.initials: MC
authors.lastname: Mandyam
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Dewland
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.forename: Steven R
authors.initials: SR
authors.lastname: Cummings
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Ellinor
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Chaitman
authors.forename: Karen
authors.initials: K
authors.lastname: Stocke
authors.forename: William B
authors.initials: WB
authors.lastname: Applegate
authors.forename: Dan E
authors.initials: DE
authors.lastname: Arking
authors.forename: Javed
authors.initials: J
authors.lastname: Butler
authors.forename: Laura R
authors.initials: LR
authors.lastname: Loehr
authors.forename: Jared W
authors.initials: JW
authors.lastname: Magnani
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Murphy
authors.forename: Suzanne
authors.initials: S
authors.lastname: Satterfield
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Marcus
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006801:Humans; D015994:Incidence; D008133:Long QT Syndrome / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
keywords: AF; ARIC; Atherosclerosis Risk in Communities; Atrial fibrillation; CHF; CHS; CI; Cardiovascular Health Study; ECG; Electrocardiogram; Epidemiology; HR; HTN; Health ABC; Health, Aging, and Body Composition; LQTS; QT corrected by using the Framingham formula; QT interval; QT(Fram); QTc; REGARDS; Reasons for Geographic and Racial Differences in Stroke; Risk; atrial fibrillation; confidence interval; congestive heart failure; corrected QT interval; electrocardiogram; hazard ratio; hypertension; long QT syndrome