title: Prevalence, correlates, and prognostic significance of QRS prolongation in heart failure with reduced and preserved ejection fraction.
abstract: OBJECTIVE
  The independent clinical correlates and prognostic impact of QRS prolongation in heart failure (HF) with reduced and preserved ejection fraction (EF) are poorly understood. The rationale for cardiac resynchronization therapy (CRT) in preserved EF is unknown. The aim was to determine the prevalence of, correlates with, and prognostic impact of QRS prolongation in HF with reduced and preserved EF.
  
  
  RESULTS
  We studied 25,171 patients (age 74.6 ± 12.0 years, 39.9% women) in the Swedish Heart Failure Registry. We assessed QRS width and 40 other clinically relevant variables. Correlates with QRS width were assessed with multivariable logistic regression, and the association between QRS width and all-cause mortality with multivariable Cox regression. Pre-specified subgroup analyses by EF were performed. Thirty-one per cent had QRS ≥120 ms. Strong predictors of QRS ≥120 ms were higher age, male gender, dilated cardiomyopathy, longer duration of HF, and lower EF. One-year survival was 77% in QRS ≥120 vs. 82% in QRS <120 ms, and 5-year survival was 42 vs. 51%, respectively (P < 0.001). The adjusted hazard ratio for all-cause mortality was 1.11 (95% confidence interval 1.04-1.18, P = 0.001) for QRS ≥120 vs. <120 ms. There was no interaction between QRS width and EF.
  
  
  CONCLUSIONS
  QRS prolongation is associated with other markers of severity in HF but is also an independent risk factor for all-cause mortality. The risk associated with QRS prolongation may be similar regardless of EF. This provides a rationale for trials of CRT in HF with preserved EF.
authors.affiliation: Department of Medicine, Karolinska Institutet, 17177 Stockholm, Sweden. lars.lund@alumni.duke.edu
authors.forename: Lars H
authors.initials: LH
authors.lastname: Lund
authors.forename: Juliane
authors.initials: J
authors.lastname: Jurga
authors.forename: Magnus
authors.initials: M
authors.lastname: Edner
authors.forename: Lina
authors.initials: L
authors.lastname: Benson
authors.forename: Ulf
authors.initials: U
authors.lastname: Dahlström
authors.forename: Cecilia
authors.initials: C
authors.lastname: Linde
authors.forename: Urban
authors.initials: U
authors.lastname: Alehagen
mesh_terms: D000367:Age Factors; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000401:mortality; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011379:Prognosis; D012042:Registries; D012307:Risk Factors; D012737:Sex Factors; D013318:Stroke Volume / Q000502:physiology