A 49-year-old man presents to the Emergency Department with a one hour history of crushing anterior chest pain:

• Sinus rhythm, 84/min
• Acute myocardial infarction – anteroseptal injury pattern

The patient underwent successful angioplasty and stenting of his left anterior descending artery and became symptom-free. This ECG was recorded one day after admission:

• Sinus rhythm

Compared with the previous tracing, there are now QRS changes of septal infarction and the ST elevation has decreased which are consistent with the evolutionary changes of a septal myocardial infarction.