STEMI Localization Chart
Match the ST-elevation leads to the wall and the culprit artery in seconds — plus the reciprocal changes and the extra leads that catch RV and posterior MIs.
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<a href="https://rcispracticetest.com/cheat-sheets/stemi-localization-chart.html">STEMI Localization Chart — RCIS Practice Test</a>Educational use only — not medical advice. Values are standard adult references; always confirm against current guidelines and your institution’s protocols.
Leads → wall → culprit artery
| ST elevation in | Wall | Likely culprit | Reciprocal changes |
|---|---|---|---|
| II, III, aVF | Inferior | RCA (or LCx if left-dominant) | I, aVL |
| V1–V2 | Septal | Proximal LAD | — |
| V3–V4 | Anterior | LAD | — |
| V1–V4 | Anteroseptal | LAD | II, III, aVF |
| I, aVL, V5–V6 | Lateral | LCx (or diagonal) | II, III, aVF |
| V7–V9 (tall R + ST↓ in V1–V3) | Posterior | RCA or LCx | ST depression V1–V3 |
| V4R | Right ventricle | Proximal RCA | — |
High-yield pearls
- Inferior STEMI + hypotension? Get a right-sided lead (V4R) — RV infarction is preload-dependent, so avoid nitrates and give fluids.
- ST depression in V1–V3 with tall R waves is often the mirror image of a posterior STEMI — obtain posterior leads V7–V9.
- New LBBB with concordant ST elevation (Sgarbossa) supports acute MI.
- Reciprocal changes increase confidence that ST elevation is a true STEMI rather than a mimic.
Drill these patterns with the ECG question bank and read the full STEMI interpretation guide.
Frequently asked questions
Which artery causes an inferior STEMI?
Inferior STEMIs (ST elevation in II, III, aVF) are usually caused by right coronary artery occlusion, or the left circumflex in left-dominant circulations.
How do you detect a right ventricular infarction?
Obtain a right-sided lead (V4R). ST elevation there, in the setting of an inferior STEMI, confirms RV involvement — treat with fluids and avoid nitrates.
What leads show a posterior MI?
Posterior MI shows as ST depression with tall R waves in V1–V3; confirm with posterior leads V7–V9, which show ST elevation.
Can I print this STEMI localization chart?
Yes — use the 'Print / Save as PDF' button at the top.
Sources & further reading
- Cardiovascular Credentialing International (CCI)
- American College of Cardiology
- American Heart Association
- MedlinePlus (U.S. National Library of Medicine)
External links are provided for reference; always confirm current details with the official source.