title: Intravenous beta-blockers in ST-segment elevation myocardial infarction: A systematic review and meta-analysis.
abstract: OBJECTIVE
  The role of intravenous (IV) beta-blockers in conjunction with percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) remains unclear. We therefore conducted a meta-analysis to assess their role in the acute phase of STEMI.
  
  
  METHODS
  We systematically searched the Cochrane Libraries, Medline, and EMBASE for RCTs comparing IV beta-blockers with inactive controls in STEMI patients undergoing PCI. The primary outcome was left ventricular ejection fraction (LVEF). Pooling was performed using DerSimonian and Laird random-effects models.
  
  
  RESULTS
  Four RCTs (n=1149) were included in our meta-analysis. All RCTs only enrolled patients with confirmed STEMI with symptoms lasting <6 or <12hours, and presenting in Killip Class 1 or 2. Mean age ranged across trials from 58.5-62.5years. Most patients were male (range: 74.8%-86.3%). Data suggest that IV beta-blockers may improve LVEF at 0-2weeks (weighted mean difference [WMD]: 1.9%; 95% confidence interval [CI]: -0.7%, 4.5%) and 4-6weeks (WMD: 1.4%; 95% CI: -3.1%, 5.9%) post-infarct, reaching statistical significance at 24weeks (WMD: 2.6%; 95% CI: 0.6%, 4.6%). Rates of ventricular arrhythmia (risk ratio [RR]: 0.65; 95% CI: 0.33, 1.29), any arrhythmia (RR: 0.67; 95% CI: 0.36, 1.27), and cardiogenic shock (RR: 0.77; 95% CI: 0.31, 1.95) during index hospitalization were numerically lower with IV beta-blockers, but 95% CIs were wide.
  
  
  CONCLUSIONS
  In STEMI patients presenting in Killip Class 1 or 2, IV beta-blockers in conjunction with PCI are associated with improved LVEF at 24weeks relative to PCI alone.
authors.affiliation: Division of Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, QC, Canada; Faculty of Medicine, McGill University, Montreal, QC, Canada.
authors.forename: Lee H
authors.initials: LH
authors.lastname: Sterling
authors.affiliation: Division of Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, QC, Canada; Faculty of Medicine, McGill University, Montreal, QC, Canada; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: Kristian B
authors.initials: KB
authors.lastname: Filion
authors.affiliation: Division of Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, QC, Canada.
authors.forename: Renee
authors.initials: R
authors.lastname: Atallah
authors.affiliation: Division of Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, QC, Canada.
authors.forename: Pauline
authors.initials: P
authors.lastname: Reynier
authors.affiliation: Division of Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, QC, Canada; Faculty of Medicine, McGill University, Montreal, QC, Canada; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada; Division of Cardiology, Jewish General Hospital/McGill University, Montreal, QC, Canada. Electronic address: mark.eisenberg@mcgill.ca.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Eisenberg
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D062645:Percutaneous Coronary Intervention / Q000379:methods*; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D000072657:ST Elevation Myocardial Infarction / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D012720:Severity of Illness Index; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: Acute coronary syndromes; Beta-blockers; Meta-analysis; STEMI; Systematic review