For a person to qualify as having a STEMI, in addition to reported angina, the ECG must show new ST elevation in two or more adjacent ECG leads. This must be greater than 2 mm (0.2 mV) for males and greater than 1.5 mm (0.15 mV) in females if in leads V2 and V3 or greater than 1 mm (0.1 mV) if it is in other ECG leads. A left bundle branch block that is believed to be new used to be considered the same as ST elevation; however, this is no longer the case. In early STEMIs there may just be peaked T waves with ST elevation developing later.

ST elevation can develop into what?