High Lateral STEMI

  • ST elevation primarily localized to leads I and aVL is referred to as a high lateral STEMI.
  • It is usually associated with reciprocal ST depression and T wave inversion in the inferior leads.
  • Sometimes referred to as the South African Flag sign
ECG High Lateral STEMI 2
Culprit vessels

Occlusion of the first diagonal branch (D1) of the left anterior descending artery (LAD) may produce isolated ST elevation in I and aVL

Occlusion of the circumflex artery may cause ST elevation in I, aVL along with leads V5-6.

South African Flag sign

High lateral STEMI is associated with pattern of ST elevation caused by acute occlusion of the first diagonal branch of the left anterior descending coronary artery (LAD-D1).

With the 4×3 display of the 12-lead ECG, the location of the most impressive ST deviations resemble the shape of the South African flag.

  • ST Elevation: Lead I, aVL, V2
  • ST Depression: Lead III (and inferior leads)

Example ECGs
Example 1
High lateral STEMI South African Flag sign

Example 2
ECG High lateral STEMI 3
ECG High lateral STEMI 3 South African Flag sign


LITFL Further Reading

Advanced Reading




Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and informatics. Asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | vocortex |

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.