title: Bundle branch block patterns and long-term outcomes in heart failure.
abstract: BACKGROUND
  The prognostic value of left and right bundle branch blocks (LBBB and RBBB) in hospitalized heart failure (HF) patients is unclear. We sought to determine the prognostic value of bundle branch blocks in patients hospitalized with heart failure.
  
  
  METHODS
  The associations of BBB type with death, HF hospitalizations or cardiovascular hospitalizations over a five year follow-up were examined within the EFFECT study of hospitalized patients fulfilling the Framingham criteria for acute heart failure. Multinomial logistic regression was used to determine associations with BBB type, and survival was assessed using multiple Cox regression analysis.
  
  
  RESULTS
  Among 9082 patients (16.3% with LBBB; 7.2% with RBBB), LBBB was independently associated with lower systolic pressure, tachycardia and hyponatremia (odds ratio [OR] of 0.93 per 10 mmHg, 1.04 per 10 beats/min, and 0.84 per 10 mmol/L, respectively). Men and diabetics (OR of 2.11 and 1.35, respectively) had greater odds of RBBB. After multiple covariate adjustment (n=7319), patients with LBBB had increased risk of HF hospitalization with adjusted hazard ratio [HR] of 1.32 (95% CI; 1.20-1.46, p<0.001) and cardiovascular hospitalization with HR of 1.13 (95% CI; 1.04-1.23, p=0.003). LBBB was associated with increased mortality with adjusted HR of 1.10 (95% CI, 1.02-1.18; p=0.011) in 7910 analysed patients. RBBB did not predict significantly increased risk of either death or hospitalization.
  
  
  CONCLUSIONS
  Heart failure patients presenting with LBBB had greater clinical severity of heart failure at presentation and greater risk of death and hospitalization for heart failure or cardiovascular disease than those without BBB. In contrast, RBBB did not independently predict worse outcomes.
authors.affiliation: Department of Medicine, University of Toronto, Toronto, Canada.
authors.forename: Husam M
authors.initials: HM
authors.lastname: Abdel-Qadir
authors.forename: Jack V
authors.initials: JV
authors.lastname: Tu
authors.forename: Peter C
authors.initials: PC
authors.lastname: Austin
authors.forename: Julie T
authors.initials: JT
authors.lastname: Wang
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000401:mortality*; D016208:Databases, Factual; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000401:mortality*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012720:Severity of Illness Index