Localizing a myocardial infarction with ECG
In a myocardial infarction, ECG findings may include:
- Q waves ≥ 1 mm in width, ≥ 33% the height of the QRS complex
- ST elevation in two or more contiguous leads or artery territory
- T wave inversion
| MI Type | Leads involved | Coronary arteries typically involved |
| Inferior | II, III, AVF | Right coronary |
| Lateral | I, AVL, V5, V6 | Circumflex |
| Antero-septal | V1, V2, V3, V4 | Left anterior descending (LAD) |
| Anterior | V3, V4 (can involve V1 to V6) | Left anterior descending |
| Antero-lateral | I, AVL, V3, V4, V5, V6 | Left anterior descending |
| Posterior | V7, V8, V9 with “mirror image” in V1, V2, V3 | Right coronary or circumflex |
| Right ventricle | V1, right chest leads VR4, VR5 | Right coronary |
| Atrial | PTa in I, V5, V6 | Right coronary |