title: Systematic review and meta-analysis of the benefits of out-of-hospital 12-lead ECG and advance notification in ST-segment elevation myocardial infarction patients.
abstract: OBJECTIVE
  To present a review of out-of-hospital identification of ST-segment elevation myocardial infarction patients transported by emergency medical services with 12-lead ECG and advance notification versus standard or no cardiac monitoring.
  
  
  METHODS
  EMBASE, PubMed, and the Cochrane Library were searched, using controlled vocabulary and keywords. Randomized controlled trials and observational studies were included. Outcomes included short-term mortality (≤30 days), door-to-balloon/needle time and/or first medical contact-to-balloon/needle time. Pooled estimates were determined, where appropriate. Results were stratified by percutaneous coronary intervention or fibrinolysis.
  
  
  RESULTS
  The search yielded 1,857 citations, of which 68 full-texts were reviewed and 16 studies met the final criteria: 15 included data on percutaneous coronary intervention and 3 on fibrinolysis (2 included both). Where percutaneous coronary intervention was performed, out-of-hospital 12-lead ECG and advance notification was associated with a 39% reduction in short-term mortality (8 studies; n=6,339; risk ratio 0.61; 95% confidence interval 0.42 to 0.89; P=.01; I(2)=30%) compared with standard or no cardiac monitoring. Where fibrinolysis was performed, out-of-hospital 12-lead ECG and advance notification was associated with a 29% reduction in short-term mortality (1 study; n=17,026; risk ratio 0.71; 95% confidence interval 0.54 to 0.93; P=.01). First medical contact-to-balloon, door-to-balloon, and door-to-needle times were consistently reduced, though large heterogeneity generally precluded pooling.
  
  
  CONCLUSIONS
  The present study adds to previous reviews by identifying and appraising the strength and quality of a larger body of evidence. Out-of-hospital identification with 12-lead ECG and aadvance notification was found to be associated with reductions in short-term mortality and first medical contact-to-balloon, door-to-balloon, and door-to-needle time.
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada. Electronic address: namj5@mcmaster.ca.
authors.forename: Julian
authors.initials: J
authors.lastname: Nam
authors.affiliation: Division of Emergency Medicine, Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Kyla
authors.initials: K
authors.lastname: Caners
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; Programs for Assessment of Technology in Health (PATH) Research Institute, St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada.
authors.forename: James M
authors.initials: JM
authors.lastname: Bowen
authors.affiliation: Division of Emergency Medicine, Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; Hamilton Health Sciences Centre for Paramedic Education and Research, Hamilton, Ontario, Canada.
authors.forename: Michelle
authors.initials: M
authors.lastname: Welsford
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; Programs for Assessment of Technology in Health (PATH) Research Institute, St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada.
authors.forename: Daria
authors.initials: D
authors.lastname: O'Reilly
mesh_terms: D004562:Electrocardiography / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D006801:Humans; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D062645:Percutaneous Coronary Intervention / Q000401:mortality / Q000706:statistics & numerical data; D013997:Time Factors