Prognostic value of the admission electrocardiogram in acute coronary syndromes

Context The presence of ischemic changes on electrocardiogram (ECC) correlates with poorer outcomes in patients with acute chest pain. Objective To determine the prognostic value of various ECC; presentations of acute myocardial ischemia. Design Retrospective analysis of the presenting ECGs of patients enrolled in Global Use of Strategies To Open Occluded Arteries in Acute Coronary Syndromes (GUSTO-IIb). Setting Three hundred seventy-three hospitals in 13 countries in North America, Europe, Australia, and New Zealand. Patients A total of 12 142 patients who reported symptoms of cardiac ischemia at rest within 12 hours of admission and had signs of myocardial ischemia confirmed by ECG. On presenting ECG, 22% of patients had T-wave inversion, 28% had ST-segment elevation, 35% had ST-segment depression, and 15% had a combination of ST-segment elevation and depression. Main Outcome Measure Ability of presenting ECG to predict death or myocardial reinfarction during the first 30 days of follow-up. Results The 30-day incidence of death or myocardial reinfarction was 5.5% in patients with T-wave inversion, 9.4% in those with ST-segment elevation, 10.5% in those with ST-segment depression, and 12.4% in those with ST-segment elevation and depression (P<.001). After adjusting for factors associated with an increased risk of 30-day death or reinfarction, compared with those who had T-wave inversion only, the odds of 30-day death or reinfarction were 1.68 (95% confidence interval [CI], 1.36-2.08) in those with ST-segment elevation, 1.62 (95% CI, 1.32-1.98) for those with ST-segment depression, and 2.27 (95% CI, 1.80-2.86) for those with combined elevation and depression. An elevated creatine kinase level at admission correlated with a higher risk of death (odds ratio [OR], 2.36; 95% CI, 1.92-2.91) and death or reinfarction (OR, 1.56; 95% CI, 1.32-1.85). The ECG category and creatine kinase level at admission remained highly predictive of death and myocardial infarction after multivariate adjustment for the significant baseline predictors of events. Conclusions The ECG at presentation allows immediate risk stratification across the spectrum of acute coronary syndromes. An elevated creatine kinase level at admission is associated with worse outcomes.