Updates on the Electrocardiogram in Acute Coronary Syndromes

The electrocardiogram (ECG) is the initial test in patients with suspected ACS. The ECG is the defining element of ST-segment elevation myocardial infarction (STEMI). Its most important use is in the detection of acute coronary obstruction, and it is the most important, cost-effective, and immediately available initial test in the decision for emergency reperfusion therapy. There is a recent interest in refining the sensitivity and specificity of the ECG for coronary occlusion, and thus for identifying subtle STEMI, as well as in recognizing pseudoinfarction patterns and thus avoiding false positive cath lab activations. Studies assessing the accuracy of cath lab activation, the differentiation of precordial ST-segment elevation due to normal variant from that of anterior STEMI, the diagnosis of STEMI in the presence of left bundle branch block, the differentiation of benign inferior ST-segment elevation from that of inferior STEMI, and the importance of ST-segment elevation in lead aVR will be discussed.