Inferior MI

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This is part of: Myocardial Infarction

ST elevation in II, III and aVF

ST elevation or depression in V4R can help in differentiating a RCA from a RCX occlusion.

This part of the heart muscle lies on the diaphragm and is supplied of blood bij the right coronary artery (RCA) in 80% of patients. In the remaing 20% the inferior wall is supplied by the ramus circumflexus(RCX).

An occlusion of the RCA can be distinguished of a RCX occulusion on the ECG:[1]

Distal RCA occlusion (sens 90%, spec 71%)
  • ST segment elevation in III higher than ST segment elevation in II ("the highest elevation points at the culprit")and
  • ST segment depression in I, AVL, or both (>1 mm)
Proximal RCA occlusion (sens 79%, spec 100%)
  • Additional ST segment elevation in V1, V4R or both
RCX occlusion (sens 83%, spec 96%)
  • ST segment elevation in I, AVL, V5, and V6 and
  • ST segment depression in V1, V2, and V3



  1. Zimetbaum PJ and Josephson ME. Use of the electrocardiogram in acute myocardial infarction. N Engl J Med. 2003 Mar 6;348(10):933-40. DOI:10.1056/NEJMra022700 | PubMed ID:12621138 | HubMed [Zimetbaum]