This document discusses how to diagnose an acute myocardial infarction (MI) using a 12-lead electrocardiogram (ECG). It explains that an MI is diagnosed by looking for ST segment elevation in certain leads that view different areas of the heart. Specifically, it states that ST elevation in leads V1-V4 indicates an anterior wall MI, leads II, III, and aVF indicate an inferior wall MI, and leads I, aVL, and V5-V6 indicate a lateral wall MI. The document uses examples of 12-lead ECGs to illustrate how to determine if a patient is experiencing an anterior, inferior, or anterolateral MI.