Initial Q waves and outcome after reperfusion therapy in patients with ST elevation acute myocardial infarction: A systematic review

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. Conclusion: The presence of initial Q waves is a relatively robust parameter to stratify outcome regardless of the reperfusion methods. (C) 2009 Elsevier Ireland Ltd. All rights reserved.