title: Gender, underutilization of cardiac resynchronization therapy, and prognostic impact of QRS prolongation and left bundle branch block in heart failure.
abstract: OBJECTIVE
  It has been suggested that cardiac resynchronization therapy (CRT) is less utilized, dyssynchrony occurs at narrower QRS, and CRT is more beneficial in women compared with men. We tested the hypotheses that (i) CRT is more underutilized and (ii) QRS prolongation and left bundle branch block (LBBB) are more harmful in women.
  
  
  RESULTS
  We studied 14 713 patients (28% women) with left ventricular ejection fraction (LVEF) <40% in the Swedish Heart Failure Registry. In women vs. men, CRT was present in 4 vs. 7% (P < 0.001) and was absent but with indication in 30 vs. 31% (P = 0.826). Next, among 13 782 patients (28% women) without CRT, 9% of women and 17% of men had non-specific intraventricular conduction delay (IVCD) and 27% of women and 24% of men had LBBB. One-year survival with narrow QRS was 85% in women and 88% in men, with IVCD 74 and 78%, and with LBBB 84 and 82%, respectively. Compared with narrow QRS, IVCD had a multivariable hazard ratio of 1.24 (95% CI 1.05-1.46, P = 0.011) in women and 1.30 (95% CI 1.19-1.42, P < 0.001) in men, and LBBB 1.03 (95% CI 0.91-1.16, P = 0.651) in women and 1.16 (95% CI 1.07-1.26, P < 0.001) in men, P for interaction between gender and QRS morphology, 0.241.
  
  
  CONCLUSIONS
  While the proportion with CRT was lower in women, CRT was equally underutilized in both genders. QRS prolongation with or without LBBB was not more harmful in women than in men. Efforts to improve CRT implementation should be directed equally towards women and men.
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm 17177, Sweden Department of Cardiology, N205, Karolinska University Hospital, Solna, Stockholm 17176, Sweden cecilia.linde@ki.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Linde
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm 17177, Sweden Department of Cardiology, N205, Karolinska University Hospital, Solna, Stockholm 17176, Sweden.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ståhlberg
authors.affiliation: Department of Clinical Science and Education, South Hospital, Karolinska Institutet, Stockholm 118 83, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Benson
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm 17177, Sweden Department of Cardiology, N205, Karolinska University Hospital, Solna, Stockholm 17176, Sweden.
authors.forename: Frieder
authors.initials: F
authors.lastname: Braunschweig
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm 17177, Sweden Department of Cardiology, N205, Karolinska University Hospital, Solna, Stockholm 17176, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Edner
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine and Health Sciences, Faculty of Health Sciences, Department of Cardiology UHL, Linköping University, County Council of Östergötland, Linköping 58191, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Dahlström
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine and Health Sciences, Faculty of Health Sciences, Department of Cardiology UHL, Linköping University, County Council of Östergötland, Linköping 58191, Sweden.
authors.forename: Urban
authors.initials: U
authors.lastname: Alehagen
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm 17177, Sweden Department of Cardiology, N205, Karolinska University Hospital, Solna, Stockholm 17176, Sweden.
authors.forename: Lars H
authors.initials: LH
authors.lastname: Lund
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000628:therapy; D053840:Brugada Syndrome; D002037:Bundle-Branch Block / Q000150:complications / Q000628:therapy*; D000075224:Cardiac Conduction System Disease; D058406:Cardiac Resynchronization Therapy / Q000706:statistics & numerical data*; D005260:Female; D019983:Guideline Adherence; D006329:Heart Conduction System / Q000002:abnormalities; D006333:Heart Failure / Q000150:complications / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017410:Practice Guidelines as Topic; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D012737:Sex Factors; D013318:Stroke Volume; D013548:Sweden
keywords: Cardiac resynchronization therapy; Epidemiology; Gender; Heart failure; Left bundle branch block; QRS width