- ST elevation primarily localised to leads I, aVL +/- V2
- Reciprocal ST depression and/or T wave inversion in inferior leads, most pronounced in lead III
- 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 left circumflex artery may cause ST elevation in I, aVL along with leads V5-6.
South African Flag sign
High lateral STEMI is associated with a 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)
- Littmann L. South African flag sign: a teaching tool for easier ECG recognition of high lateral infarct. Am J Emerg Med. 2016 Jan;34(1):107-9.
- Durant E, Singh A. Acute first diagonal artery occlusion: a characteristic pattern of ST elevation in noncontiguous leads. Am J Emerg Med. 2015 Sep;33(9):1326
- Wiesbauer F, Kühn P. ECG Yellow Belt online course: Become an ECG expert. Medmastery
- Wiesbauer F, Kühn P. ECG Blue Belt online course: Learn to diagnose any rhythm problem. Medmastery
- Rawshani A. Clinical ECG Interpretation ECG Waves
- Smith SW. Dr Smith’s ECG blog.
- Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
- Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
- Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
- Hampton J. The ECG Made Practical 7e, 2019
- Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography 1e, 2009
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
- Mattu A, Brady W. ECG’s for the Emergency Physician Part I 1e, 2003 and Part II
- Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004
- Smith SW. The ECG in Acute MI. 2002 [PDF]
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest
Associate Professor Curtin Medical School, Curtin University. Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM Sir Charles Gairdner Hospital. Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |