Predictive value of Q waves on the 12-lead electrocardiogram after reperfusion therapy for ST elevation myocardial infarction

Abstract

Design The data used for the present study were obtained as part of a clinical trial evaluating the effect of thrombus aspiration after primary percutaneous coronary intervention (PCI). Setting The study was conducted at a tertiary referral facility for primary PCI at a University Medical Center Groningen in The Netherlands. Background Prognosis after ST elevation myocardial infarction (STEMI) is strongly related to infarct size. Methods As part of a randomized clinical trial, the first electrocardiogram (ECG) after primary PCI for STEMI was analyzed for the incidence of Q waves (>0.1 mV) on the 12-lead ECG. Infarct size was measured as area under curve (AUC) of creatine kinase (CK) and CK-myocardial band (CK-MB). Results and Conclusion Nine hundred thirty-three patients were included, the median number of Q waves on the postprocedural ECG was 3 (interquartile range, 1-4). The number of Q waves on the postprocedural ECG was an independent predictor of infarct size measured either as AUC of CK ( P < .001) or AUC of CK-MB ( P < .001) and was a significant predictor of mortality during follow-up of 14 months. In conclusion, the number of Q waves on the postprocedural 12-lead ECG after primary PCI for STEMI is a strong predictor of infarct size and long-term mortality.