Chapter 2
Electrocardiographic Identification of the Culprit Lesion in ST-Segment Elevation Myocardial Infarction
Simon Chakko, MD, FACC, FACP

Introduction
Despite the development of many sophisticated imaging technologies in the last decade, electrocardiogram (ECG) is considered to be the single most important initial clinical test for diagnosing acute myocardial infarction. The 12-lead ECG is the center of the therapeutic decision pathway to determine if the patient will benefit from reperfusion therapy. ECG is very helpful in localizing the coronary obstruction and various studies have shown a good correlation between ECG and coronary angiography performed in temporal proximity of acute ST-segment elevation myocardial infarction (STEMI). Determining the culprit lesion in STEMI may be helpful in deciding if fibrinolysis or primary coronary intervention is the best approach. Furthermore, among patients with multiple stenoses in the coronary angiogram, it may be difficult to determine which of the many lesions is the culprit. ECG is often helpful in such situations. In this chapter, the use of ECG in identifying the coronary obstruction that caused the STEMI is discussed.