Assess the ST segment for the presence of elevations or depressions, together with T wave abnormalities. ST elevation can indicate the presence of conditions such as acute myocardial injury, Prinzmetal's (variant) angina, pericarditis, ventricular aneurysm or myocardial ischemia.

This ECG is from a patient with an acute inferior MI. Note the ST elevation in the inferior leads (II, III and aVF). The ECG also shows ST depression in leads V1, V2 and V3 - likely a result of reciprocal changes associated with the MI.