PROGNOSTIC-SIGNIFICANCE OF THE INITIAL ELECTROCARDIOGRAM IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

Context.-Early risk stratification of patients with myocardial infarct ion is critical to determine optimum treatment strategies and enhance outcomes, but knowledge of the prognostic importance of the initial el ectrocardiogram (ECG) is limited. Objective.-To assess the independent value of the initial ECG for short-term risk stratification after acu te myocardial infarction. Design.-Retrospective analysis of the Global Utilization of Streptokinase and t-PA (alteplase) for Occluded Corona ry Arteries (GUSTO-I) clinical trial database. Setting.-A total of 108 1 hospitals in 15 countries. Patients.-From the 41 021 patients enroll ed in the overall study, we selected those who presented within 6 hour s of chest pain onset with ST-segment elevation and no confounding fac tors (paced rhythms, ventricular rhythms, or left bundle-branch block) on the ECG performed before thrombolysis was administered (n=34 166). Main Outcome Measure.-Ability of initial ECG to predict all-cause mor tality at 30 days. Results.-Most ECG variables were associated with 30 -day mortality in a univariable analysis, In a multivariable analysis combining the initial ECG variables and clinical predictors of mortali ty, the sum of the absolute ST-segment deviation (both ST elevation an d ST depression: odds ratio [OR], 1.53; 95% confidence interval [CI], 1.38-1.69), ECG, heart rate (OR, 1.49; 95% CI, 1.41-1.59), QRS duratio n (for anterior infarct: OR, 1.55; 95% CI, 1.43-1.68), and ECG evidenc e of prior infarction (for new inferior infarct: OR, 2.47; 95% CI, 2.0 2-3.00) were the strongest ECG predictors of mortality, A nomogram bas ed on the multivariable model produced excellent discrimination of 30- day mortality (C-index, 0.830). Conclusions.-In patients presenting wi th myocardial infarction accompanied by ST-segment elevation, componen ts of the initial ECG help predict 30-day mortality, This information should be valuable in early risk stratification, when the opportunity to reduce mortality is greatest, and may help in assessing outcomes ad justed for patient risk.