Chart — Cardiac
Coronary Artery Territories Chart
Quick-reference chart for coronary artery territories — each artery organized by areas supplied, ECG leads affected, MI location, and common complications for nurses in cardiac, ICU, and emergency settings.
Educational use only. Coronary anatomy varies among individuals; right vs. left dominance affects posterior territory. This chart reflects typical right-dominant anatomy unless noted. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Coronary Artery Territories
| Artery | Areas Supplied | ECG Leads | Common Complications |
|---|---|---|---|
| LMCALeft Main Coronary Artery | Bifurcates into LAD and LCx — supplies majority of LV; occlusion affects both LAD and LCx territories | Diffuse — widespread ST depression + ST elevation in aVR ± V1 (reciprocal pattern) | Cardiogenic shock, acute pulmonary edema, very high mortality; often called 'widowmaker' |
| LADLeft Anterior Descending | Anterior wall LV, anterior interventricular septum, anterior papillary muscle (partial), bundle branches (proximal LAD) | V1–V4 (anterior leads); high lateral involvement with diagonal branches: I, aVL | Largest MI territory; cardiogenic shock; LBBB or RBBB; complete heart block (proximal); ventricular aneurysm; papillary muscle rupture (mitral regurgitation) |
| LCxLeft Circumflex | Lateral wall of LV, posterior wall (if left-dominant), SA node (40%), AV node (10%) | I, aVL, V5–V6 (lateral leads); posterior MI: ST depression V1–V3 (reciprocal) | Often clinically silent; posterior MI commonly missed; SA node dysfunction if dominant; mitral regurgitation (lateral papillary muscle) |
| RCARight Coronary Artery | Right ventricle, inferior wall LV (right-dominant), SA node (~60%), AV node (~90%), posterior descending artery (right-dominant) | II, III, aVF (inferior leads); RV infarct: right-sided leads V4R–V6R | Bradycardia (SA/AV node); high-degree AV blocks (Mobitz I, complete); RV infarct → hemodynamic instability; hypotension with NTG (preload-dependent RV) |
| PDAPosterior Descending Artery | Posterior wall LV, posterior interventricular septum; supplied by RCA (right-dominant) or LCx (left-dominant) | Posterior MI: ST depression in V1–V3 (reciprocal); tall R in V1; confirmed by ST elevation in V7–V9 | Missed diagnosis is the biggest risk; obtain posterior leads (V7–V9) for confirmation |
MI Location Quick Reference
| MI Location | ST Elevation Leads | Artery | Critical Watch Point |
|---|---|---|---|
| Anterior | V1–V4 | LAD (proximal) | LBBB, complete block, cardiogenic shock |
| Anteroseptal | V1–V2 | LAD (septal perforators) | Bundle branch blocks |
| Anterolateral | V1–V6, I, aVL | LAD or LMCA | Large territory; MR; cardiogenic shock |
| Lateral (high) | I, aVL | LCx or diagonal | Often silent or atypical |
| Lateral (low) | V5–V6 | LCx | Check with high lateral + anterior |
| Inferior | II, III, aVF | RCA (right-dominant) | RV infarct — check V4R; avoid NTG; AV blocks |
| Right Ventricular | V4R–V6R (right-sided ECG) | RCA | Preload-dependent — give fluids, avoid NTG |
| Posterior | V7–V9 elevation (V1–V3 depression reciprocal) | RCA or LCx (dominant) | Missed if no posterior leads — order V7–V9 |
Special Situations to Know
Inferior STEMI + RV InfarctInferior STEMI (II, III, aVF) with RCA involvement puts the RV at risk. Right-sided ECG (V4R elevation ≥1 mm) confirms RV infarct. RV is preload-dependent — avoid nitroglycerin, diuretics, and vasodilators. Fluid challenge may be needed. Monitor for high-degree AV block.
Posterior MI — Missed PresentationStandard 12-lead shows ST DEPRESSION in V1–V3 (not elevation). Posterior MI mimics 'non-STEMI' on standard ECG. Always obtain posterior leads V7–V9 when ST depression in V1–V3 + tall R wave in V1 + upright T waves is seen. V7–V9 elevation ≥0.5 mm confirms posterior STEMI.
Dominant Circumflex = Left-DominantIn ~15% of patients, the LCx supplies the PDA (left-dominant system). In left-dominant anatomy, LCx occlusion affects both lateral AND inferior territories. AV node is supplied by LCx (not RCA) — AV blocks may occur with LCx occlusion.
LMCA Equivalent PatternWidespread ST depression in multiple leads + ST elevation in aVR ≥1 mm suggests LMCA or proximal LAD occlusion. This is a catastrophic pattern — cath lab activation immediately regardless of whether lead-based STEMI criteria are met.
NCLEX Pearls
- ›LAD = anterior STEMI (V1–V4) — largest territory; highest mortality.
- ›RCA = inferior STEMI (II, III, aVF) + RV infarct risk + AV block risk (supplies SA/AV nodes).
- ›Inferior STEMI: always obtain right-sided ECG (V4R) before giving nitroglycerin.
- ›LCx territory (lateral) often presents atypically — check I, aVL, V5–V6 for lateral changes.
- ›Posterior MI: ST depression in V1–V3 is the clue → obtain V7–V9; do not mistake for NSTEMI.
- ›LMCA occlusion: widespread ST depression + ST elevation in aVR = catastrophic — activate cath lab.
Related Resources
Coronary Artery Anatomy ReferenceFull description of each coronary artery, territories, and infarct locations
Open →STEMI Activation Criteria ReferenceECG criteria, contiguous leads, LBBB, posterior MI clues, immediate actions
Open →ACS Comparison ChartStable angina, UA, NSTEMI, STEMI — ECG, troponins, occlusion, urgency
Open →ECG Interpretation Fundamentals GuideSystematic ECG reading: intervals, BBB, ST analysis, AV blocks
Open →EKG Rhythm Chart14 cardiac rhythms with rate, regularity, P wave, PR interval, QRS features
Open →Standards & sources
Fact-checked Jun 20, 2026This page is written to align with AHA / ACC Coronary Anatomy Standards. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →