Reviewed October 2026. The ECG suggests the territory of ischaemia or infarction, but does not identify the culprit artery with certainty. Coronary dominance, multivessel disease, collateral circulation and anatomical variants affect localisation.
Common ECG territories
- Anterior / septal: predominantly V1–V4; frequently left anterior descending (LAD) artery.
- Lateral: I, aVL, V5–V6; frequently circumflex/diagonal territory.
- Inferior: II, III, aVF; most often right coronary artery (RCA), sometimes circumflex depending on dominance.
- Posterior: horizontal ST depression V1–V3, often with tall R waves and upright terminal T waves; confirm with posterior leads V7–V9 when appropriate.
- Right ventricle: evaluate V3R–V4R in suspected inferior infarction.
Use reciprocal changes and serial ECGs. An occlusion may exist without conventional ST-elevation thresholds; persistent symptoms or instability warrant immediate assessment.
ECG anatomy illustration
Original illustration courtesy of Dr Tor Ercleve / Life in the Fast Lane. The diagram is a learning aid, not a definitive coronary artery map.
Reference: ESC 2023 Acute Coronary Syndromes Guidelines.
