title: Different patterns of bundle-branch blocks and the risk of incident heart failure in the Women's Health Initiative (WHI) study.
abstract: BACKGROUND
  We evaluated the risk of incident heart failure (HF) associated with bundle-branch blocks (BBBs) in postmenopausal women.
  
  
  RESULTS
  Cox's regression was used to evaluate hazard ratios with 95% confidence intervals for HF among 65975 participants of the Women's Health Initiative (WHI) study during an average follow-up of 14 years. BBBs observed in 1676 women at baseline were categorized into left, right, and indetermined-type BBBs (LBBB, RBBB, and intraventricular conduction defect, respectively). Compared with women with no BBB, LBBB, and intraventricular conduction defect were strong predictors of incident HF in multivariable-adjusted risk models (hazard ratio, 3.79; confidence interval, 2.95-4.87 for LBBB and hazard ratio, 3.53; confidence interval, 2.14-5.81 for intraventricular conduction defect). RBBB was not a significant predictor of incident HF in multivariable-adjusted risk model, but the combination of RBBB and left anterior fascicular block was a strong predictor (hazard ratio, 2.96; confidence interval, 1.77-4.93). QRS duration was an independent predictor of incident HF only in LBBB, with more pronounced risk at QRS ≥ 140 ms than at <140 ms. QRS nondipolar voltage (RNDPV) was an independent predictor in both RBBB and LBBB and, in addition, in LBBB, QRS/STT angle and ST J-point depression in aVL were independent predictors.
  
  
  CONCLUSIONS
  LBBB, intraventricular conduction defect, and RBBB combined with left anterior fascicular block are strong predictors of incident HF in multivariable-adjusted risk models, but RBBB is not a significant predictor. QRS duration ≥ 140 ms may warrant consideration in LBBB as an indication for further diagnostic evaluation for possible therapeutic and preventive action. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000611.
authors.affiliation: Epidemiological Cardiology Research Center, Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA. zmzhang@wakehealth.edu
authors.forename: Zhu-ming
authors.initials: ZM
authors.lastname: Zhang
authors.forename: Pentti M
authors.initials: PM
authors.lastname: Rautaharju
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.forename: Joann E
authors.initials: JE
authors.lastname: Manson
authors.forename: Lisa W
authors.initials: LW
authors.lastname: Martin
authors.forename: Marco
authors.initials: M
authors.lastname: Perez
authors.forename: Mara
authors.initials: M
authors.lastname: Vitolins
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Prineas
mesh_terms: D002037:Bundle-Branch Block / Q000453:epidemiology* / Q000503:physiopathology; D015331:Cohort Studies; D015897:Comorbidity; D003663:Decision Trees; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006333:Heart Failure / Q000188:drug therapy / Q000453:epidemiology*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D016016:Proportional Hazards Models
keywords: QRS duration; bundle-branch block; electrocardiography; heart failure; repolarization