Usefulness of standard electrocardiographic parameters for predicting cardiac events after acute myocardial infarction during modern treatment era

Abstract

Comprehensive information about the independent value of different electrocardiographic (ECG) variables in predicting cardiac events after acute myocardial infarction (AMI) in the era of modern therapy is limited. Patients (n = 1,034) underwent standard electrocardiography from 5 to 7 days after an AMI. Several time intervals and PQRST abnormalities were analyzed from the electrocardiogram. During a mean ± SD follow-up of 752 ± 301 days on average, 42 patients (4%) experienced cardiac death, and 259 patients (25%) a cardiac death, nonfatal AMI, or unstable angina. Several ECG variables had a significant association with cardiac events in univariate comparisons. After adjustment for all risk variables in the Cox hazards model, lateral ST-segment depression (hazard ratio [HR] 4.76, 95% confidence interval [CI] 2.40 to 9.44, p <0.0001) and atrial abnormality with a terminal deflection of the P wave ≥0.1 mV deep and ≥40 ms in duration in lead V1 (HR 2.46, 95% CI 1.25 to 4.82, p = 0.009) were the only ECG variables that independently predicted cardiac death. Lateral ST-segment depression also predicted the combined end point of cardiac death/nonfatal AMI/unstable angina in this model (HR 1.49, 95% CI 1.14 to 1.94, p = 0.003). In conclusion, lateral ST depression and atrial abnormality on the electrocardiogram are independent predictors of cardiac death after AMI. Lateral ST depression is also associated with ischemic cardiac events.