A patient presents to A&E with acute onset chest pain radiating into the neck and left arm. The patient is short of breath and sweating and reports some nausea. An ECG is preformed showing ST elevation in leads II, III and AVF. Where is the infarction most likely to be situated and which cardiac territory is affected?

A) Right coronary artery affecting the inferior territory of the heart.
B) Left anterior descending artery affecting the anterior territory of the heart.
C) Left circumflex artery affecting the lateral territory of the heart.
D) Left circumflex artery affecting the septum of the heart.
E) Left anterior descending artery affecting the inferior territory of the heart.

P.S. Sorry about not actually having an ECG for this question. If anyone knows of a site with ECG pictures licensed under the creative commons act, let me know.


The answer is A.

This picture nicely illustrates the blood supply to the heart:
Taken from http://www.patient.co.uk/health/How-the-Heart-Works.htm

Leads II, III and AVF look at the below and therefore ST elevation in these leads would indicate an inferior MI - and as the right coronary artery supplies this area it is the most likely culprit.

ST elevation in V2, V3 and V4 would indicate an infarction in the left anterior descending artery [LAD], this is the most common site of MI.

ST elevation in I, AVL, V5 and V6 would indicate an infarction in the lateral territory, which is supplied by the left circumflex artery.

ST elevation in V1 and V2 would indicate infarction in the septal territory which is supplied by the right coronary artery and partially by the LAD.