1.10 Localization of MI on ECG

Cardiovascular system review for the USMLE Step 1 exam T

• Myocardial infarction (MI) can be localized by identifying changes in various ECG leads
• Anterior STEMI: ST elevation in precordial leads V3, V4, indicating occlusion of the distal left anterior descending artery (LAD)
• Lateral MI: ST elevation in leads I, aVL, aVR, and precordial leads V5, V6, caused by an occlusion of the LAD
• Septal MI: ST elevation in leads V1, V2, V3, caused by an occlusion to the LAD
• Inferior MI: ST elevation in leads II, III, aVF, caused by an occlusion of the right coronary artery (RCA)
• Posterior MI: ST elevation in V7, V8, V9, caused by an occlusion of the posterior descending artery (PDA)