title: Initial Q waves and outcome after reperfusion therapy in patients with ST elevation acute myocardial infarction: a systematic review.
abstract: BACKGROUND
  Patients with ST elevation acute myocardial infarction (STEMI) have different outcome depending on the reperfusion strategy.
  
  
  METHODS
  To discern if the presence of initial Q waves in the infarct leads is a useful prognostic parameter in STEMI patients within 6 h of symptom onset treated by different reperfusion strategies (fibrinolysis, fibrinolysis followed by percutaneous coronary intervention [PCI], and primary PCI) we performed a systematic review on outcome comparing patients with and without initial Q waves.
  
  
  RESULTS
  The relative risks for those with Q waves were significantly raised for both mortality and the composite outcome of mortality, congestive heart failure or cardiogenic shock, and at both 30-day and 90-day time points. The relative risk for mortality varied from 2.18 (95% CI 1.32-3.61) at 30 days to 2.54 (95% CI 1.87-3.44) at 90 days. The relative risk for composite outcome was 2.28 (95% CI 1.71-3.04) at 30 days and 2.25 (95% CI 1.81-2.80) at 90 days.
  
  
  CONCLUSIONS
  The presence of initial Q waves is a relatively robust parameter to stratify outcome regardless of the reperfusion methods.
authors.affiliation: Department of Cardiology, Dunedin School of Medicine, University of Otago, Dunedin Public Hospital, Dunedin, New Zealand. cheuk-kit.wong@healthotago.co.nz
authors.forename: Cheuk-Kit
authors.initials: CK
authors.lastname: Wong
authors.forename: Peter
authors.initials: P
authors.lastname: Herbison
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000379:methods; D000818:Animals; D004562:Electrocardiography / Q000379:methods; D005342:Fibrinolysis / Q000502:physiology; D006801:Humans; D009203:Myocardial Infarction / Q000503:physiopathology* / Q000628:therapy*; D015425:Myocardial Reperfusion / Q000009:adverse effects / Q000379:methods; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D012307:Risk Factors