Only 70% of patients with MI can be diagnosed on ECG, leaving 30% of patients with acute or chronic MI that are not recognized on the ECG. False-negative results may be a result of:

1. Small infarctions
2. Infarctions associated with LBBB
3. Multiple infarctions where one infarction masks the other
4. The ECG’s inherent indirect method of analyzing cardiac function

However, electrocardiography can recognize MI in many cases with the advantage of reliable localization and staging. Clinical progression can be observed along with the evolution of alterations in ECG morphology.