Localization of ST-segment elevation myocardial infarction (STEMI)

Involved myocardium

ST-segment elevation leads

Occluded vessel

Septal

V₁, V₂

LAD

Anterior

V₃, V₄

LAD

Lateral

V₅, V₆, I, aVL

LAD or LCx

Inferior

II, III, aVF

RCA or LCx

Inferolateral*
(posterior)

V₇-V₉

RCA or LCx

Right ventricle**

V₄R-V₆R

RCA

*The inferolateral (or posterior) wall is electrically silent using standard ECG lead placement; STEMI of this region is suggested by ST-depression in leads V₁-V₃ & confirmed by ST-elevation in supplemental leads V₇-V₉.

**Half of inferior STEMIs involve the right ventricle; confirmed by ST-elevation in right-sided leads V₄R-V₆R.

LAD = left anterior descending artery; LCx = left circumflex artery; RCA = right coronary artery.