title: Intraventricular conduction defects in patients with congestive heart failure: left but not right bundle branch block is an independent predictor of prognosis. A report from the Italian Network on Congestive Heart Failure (IN-CHF database).
abstract: BACKGROUND
  In industrialized countries the prevalence of congestive heart failure (CHF) is increasing. Many clinical factors have been shown to influence the prognosis of CHF. The effect of a wide QRS on mortality is debated; while left bundle branch block (LBBB) has been already identified as a negative prognostic factor, the effect of right bundle branch block (RBBB) is still unknown. The aim of this study was to compare the association of these two intraventricular conduction defects on the prognosis of CHF.
  
  
  METHODS
  Data were derived from the Italian Registry of CHF. Entry in the Registry required that patients had a diagnosis of CHF based on the European Society of Cardiology guidelines. We analyzed the 1-year follow-up data of 5517 outpatients with CHF of different etiologies. The presence of a wide QRS was defined if the duration was > 120 ms.
  
  
  RESULTS
  A wide QRS was present in 2066 patients (37.5%), 25.2% with LBBB, 6.1% with RBBB, 6.2% with other intraventricular defects. At univariate analysis patients with complete LBBB had a significantly higher 1-year mortality than those without (16.1 vs 11.9%) but this was not true for complete RBBB (11.9 vs 11.9%). Even after multivariate adjustment, complete LBBB still remained an independent predictor of death (relative risk 1.36, 95% confidence interval 1.15-1.61).
  
  
  CONCLUSIONS
  LBBB but not RBBB is an independent predictor of death in CHF.
authors.affiliation: Italian Association of Hospital Cardiologists (ANMCO) Research Center, Florence, Italy.
authors.forename: Samuele
authors.initials: S
authors.lastname: Baldasseroni
authors.forename: Anna
authors.initials: A
authors.lastname: Gentile
authors.forename: Marco
authors.initials: M
authors.lastname: Gorini
authors.forename: Niccolò
authors.initials: N
authors.lastname: Marchionni
authors.forename: Maurizio
authors.initials: M
authors.lastname: Marini
authors.forename: Giulio
authors.initials: G
authors.lastname: Masotti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Porcu
authors.forename: Aldo P
authors.initials: AP
authors.lastname: Maggioni
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000473:pathology*; D006333:Heart Failure / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology; D016019:Survival Analysis