title: Discordant vs. concordant left bundle branch block: A potential clinical significance.
abstract: OBJECTIVE
  LBBB in heart failure patients has prognostic significance. Subtypes of LBBB (concordant and discordant) have not been considered when considering management. The aim of this study is to explore the clinical difference between the two subtypes.
  
  
  METHODS
  216 patients with LBBB were included and categorized into concordant (LBBBC) and discordant (LBBBD) groups.
  
  
  RESULTS
  Of the 216 patients (age 69.13±11.7; 56% male 44% female), 133 (61.5%) were LBBBD and 83 (38.5%) were LBBBC. LBBBD patients presented with lower LVEF (mean 36% vs 51%; P<0.001), wider QRS (mean 160 ms vs 151 ms; P<0.001), larger LA (mean 45 cm(2) vs 40 cm(2); P<0.001), moderate to severe mitral and tricuspid regurgitation (17% vs 3%; P<0.05, 10% vs 1%; P<0.05 respectively), CKD (41% vs 18%; P<0.001), COPD (4.6% vs 0%; P<0.01), CAD (67% vs 36%; P<0.001), and CABG (39% vs 16%; P<0.001).
  
  
  CONCLUSIONS
  LBBBD is significantly associated with worse cardiac function and clinical characteristics.
authors.affiliation: American University of Beirut Medical Center, Lebanon.
authors.forename: Jalkh
authors.initials: J
authors.lastname: Khalil
authors.affiliation: American University of Beirut Medical Center, Lebanon.
authors.forename: Abi Saleh
authors.initials: AS
authors.lastname: Bernard
authors.affiliation: American University of Beirut Medical Center, Lebanon.
authors.forename: Khoury
authors.initials: K
authors.lastname: Maurice
authors.affiliation: Cardiff Hospital, UK.
authors.forename: Yousef
authors.initials: Y
authors.lastname: Zaheer
authors.affiliation: American University of Beirut Medical Center, Lebanon.
authors.forename: Refaat
authors.initials: R
authors.lastname: Marwan
authors.affiliation: American University of Beirut Medical Center, Lebanon.
authors.forename: Rebeiz
authors.initials: R
authors.lastname: Abdallah
authors.affiliation: American University of Beirut Medical Center, Lebanon.
authors.forename: Alam
authors.initials: A
authors.lastname: Samir
authors.affiliation: American University of Beirut Medical Center, Lebanon. Electronic address: hs13@aub.edu.lb.
authors.forename: Skouri
authors.initials: S
authors.lastname: Hadi
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology*; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000401:mortality*; D004562:Electrocardiography; D005260:Female; D006349:Heart Valve Diseases / Q000401:mortality*; D006801:Humans; D007861:Lebanon / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000453:epidemiology*
keywords: CRT; Dyssynchrony; Heart failure; Left bundle branch block