Context

The need to establish the correct diagnosis in patients who have ST segment elevation on their ECG is paramount when considering that the most important differential is ST elevation myocardial infarction (STEMI).

There are two main issues when trying to diagnose STEMI: (i) the speed with which we need to make the diagnosis because of the time critical nature of treatment and (ii) the potential consequences of inappropriate urgent reperfusion therapy (i.e. thrombolysis or angioplasty).

The interpretation of the ECG is usually made under time pressure and without the luxury of added investigations to help clarify the diagnosis. Consequently we need to rely on our clinical assessment (i.e. history and examination) of the patient in conjunction with our interpretation of the ECG in order to make the correct diagnosis.