The Initial Electrocardiographic Pattern in Acute Myocardial Infarction

Abstract

Background: The ECG is the most widely used accessory for early diagnosis and risk stratification of patients with acute myocardial infarction (AMI). Previous studies have concentrated on the association between either the number of leads with ST segment deviation (elevation and depression) or the total amount of ST segment elevation and/or depression and prognosis. However, the results are conflicting.Methods: A different method is to use the grades of ischemia as an estimate of infarct or size and prognosis. Grade I ischemia is defined as tall peak T waves with < 0.1 mV ST segment elevation; grade II as ST segment elevation with positive T waves, without distortion of the terminal portion of the QRS; and grade III as ST segment elevation, positive T waves, and distortion of the terminal portion of the QRS. Grade III ischemia on the admission ECG is associated with larger final infarct size and increased mortality.Results: In patients with inferior wall AMI, especially those with prior infarction, the pattern of precordial ST segment depression is even more important and maximal ST depression in V4‐V6 is associated with high mortality. Moreover, meticulous interpretation of the initial ECG pattern provides information about the probable site of the culprit obstructive coronary lesion.Conclusion: Thus, the admission ECG of AMI can assist not only in diagnosis, but also in estimation of infarct size, correlation with the underlying coronary anatomy and risk stratification.