The ECG criteria of an anterior wall myocardial infarction (STEMI) with 12-lead ECG examples are discussed including an old anterior wall MI and left ventricular (LV) aneurysm. The leads (V7 through V9) placed over the posterior (or lateral) wall would have shown ST elevation. In the remaing 20% the inferior wall is supplied by the ramus circumflexus(RCX). Elevation of ST segment indicates zone of injury, diagnosis is supported by reciprocal changes, ST segment depression in the leads facing the opposite wall. Remember that the inferior leads make up the lower-left corner of the 12 lead ECG. The thing that makes this EKG suspicious for posterior MI is the ST depression in v1-v3. ... this post is for you xD. If you put posterior leads on (v7-v9), you'd likely see ST elevation there. The inferior leads (II, III and aVF) view the inferior wall of the left ventricle. That is why we group the leads of the electrocardiogram depending on the nearest heart wall. The septal leads (V1 and V2) view the septal wall of the left ventricle. An infarct is heart tissue that dies from a heart attack, which electrocardiograms, or EKG/ECG, detect because the dead muscle no longer contracts, according to WebMD and the American Heart Association. There also happens to be an inferior MI going on as you can see from the limb leads. Warning: This is an over simplified post. For precordial leads, I use the "SAL" mnemonic. STE III > STE II suggests occlusion of the right coronary artery (RCA) which suggests the possibility of RV infarction. Inferior wall infarction on an initial ECG, manifested as ST-segment elevations in leads II, III, and aVF, should prompt further investigation for evidence of RV involvement (see Figure 1). For example: the inferior leads provide more information from the inferior wall of the heart than the rest of the walls. They are often grouped together with the anterior leads. Leads v1-v3 are reciprocal to the posterior leads. An occlusion of the RCA can be distinguished of a RCX occulusion on the ECG: Distal RCA occlusion (sens 90%, spec 71%) 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. Zones of MI, leads and ECG mnemonic Hey! The "reciprocal changes" in leads V1 through V3 are not to the ST elevation in leads II, III and aVF, but actually to an infarction of the posterior (now we should really be saying "lateral") wall. An EKG/ECG that finds dead tissue of undetermined age in the inferior heart wall is called an "inferior infarct, age undetermined." ST-segment elevation is noted in leads II, III, and aVF with reciprocal changes in leads I and aVL. The vast majority (80–90%) of patients with ST elevation in these “inferior” leads has an occlusion of the right coronary artery; however, an occlusion of the left circumflex artery can produce a similar ECG pattern. 53.3% of patients with inferior wall MI had reciprocal changes ≥ ST elevation in inferior leads 1; 70 – 97.2% of patients with inferior wall MI had reciprocal changes in aVL 2,3; 30% of patients with anterior wall MI had reciprocal changes in aVL 3; Can lead aVL give prognostic information for acute MI? A 12-lead ECG is obtained. Naturally, each lead provides more information from the nearest wall tan distant walls (electrically speaking).