title: The prognostic value of a new left bundle branch block in patients with acute myocardial infarction: A systematic review and meta-analysis.
abstract: OBJECTIVE
  To assess the prognostic value of new left bundle branch block (LBBB) in patients with acute myocardial infarction (AMI).
  
  
  BACKGROUND
  LBBB develops in many cardiac conditions, including AMI. The empirical evidence for the contribution of LBBB to mortality in AMI is not consistent.
  
  
  METHODS
  Medline, PubMed, CINAHL, and EMBASE were searched. Inverse variance meta-analysis was performed with odds ratios as the effect estimates. The I2statistic and risk of bias were assessed.
  
  
  RESULTS
  Eight studies involving 105,861 participants were eligible. New LBBB was associated with higher mortality at 30 days (OR: 2.10, 95% CI 1.27 to 3.48) and 1-year follow up (OR: 2.81, 95% CI 1.64 to 4.80), and increased heart failure risk (OR: 2.64, 95% CI 1.84 to 3.77).
  
  
  CONCLUSIONS
  AMI patients with new LBBB are a high risk group and must be treated accordingly. Yet, more research is needed given the limitations of studies.
authors.affiliation: Birzeit University, Palestine.
authors.forename: Belal
authors.initials: B
authors.lastname: Al Rajoub
authors.affiliation: Hariri School of Nursing, American University of Beirut, Lebanon. Electronic address: sn00@aub.edu.lb.
authors.forename: Samar
authors.initials: S
authors.lastname: Noureddine
authors.affiliation: Labib Medical Center, Lebanon.
authors.forename: Samer
authors.initials: S
authors.lastname: El Chami
authors.affiliation: Lebanese American University Medical Center, Lebanon.
authors.forename: Mohamad Hussein
authors.initials: MH
authors.lastname: Haidar
authors.affiliation: American University of Beirut, Lebanon.
authors.forename: Bachir
authors.initials: B
authors.lastname: Itani
authors.affiliation: American University of Beirut, Lebanon.
authors.forename: Aida
authors.initials: A
authors.lastname: Zaiter
authors.affiliation: Faculty of Medicine, American University of Beirut, Lebanon.
authors.forename: Elie A
authors.initials: EA
authors.lastname: Akl
mesh_terms: D002037:Bundle-Branch Block / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D004562:Electrocardiography; D014943:Global Health; D006801:Humans; D015994:Incidence; D009203:Myocardial Infarction / Q000150:complications*; D016017:Odds Ratio; D011379:Prognosis; D018570:Risk Assessment / Q000379:methods*; D015996:Survival Rate / Q000639:trends
keywords: Acute myocardial infarction; Bundle branch block; Meta-analysis; Mortality; Prognosis