Anterior Myocardial Infarction

Anterior wall myocardial infarction can be characterized by ST-T changes in V2-V4. An extensive anterior infarction can involve wider territory encompassing V1-V4 (septal), I and aVL (anterior), V4-V6 (lateral), II III and aVF (inferior).  The ECG below displays an extensive anterior MI. The patient went to the cardiac catheterization laboratory and was found to have a totally occluded proximal LAD. This patient also had evidence of RV infarction and was admitted to the ICU for hemodynamic monitoring.

The ECG below is an example of a more distal LAD lesion with STEMI involving the anteroseptal distribution (V1-V3). This patient also went to the catheterization laboratory and was found to have a total occlusion of the LAD before the first septal perforator.

An anterolateral MI would involve V3-V6, I and aVL with reciprocal changes in II, III and aVF. The following ECG is an example of NSTEMI in the anterolateral distribution.

Lateral MI

Lateral wall MI are characterized by acute ST changes in leads I, aVL, V5 and V6. This ECG distribution is usually associated with an acute left circumflex artery lesion. Here is an example of an inferolateral injury pattern.

The above patient was found to have 3 vessel disease including 70% LAD, total occluded RCA with L->R collaterals, and 80% 1st diagonal branch.

 

Inferior Wall MI

Characterized by STEMI in leads I, III, and aVF. Usual distribution posterior descending artery, if extensive, RCA. The left circumflex can also be involved.

Here is another example of a large inferior wall MI with reciprocal changes in I and aVL. There also appears to be posterior wall involvement as well (deep inverted segments in V1-V2).

Posterior MIPosterior wall MI usually is associated with large inferior wall MIs.  They usually are characterized by deep ST depression in V1-V2,V3, and are mirror image of an anteroseptal MI. Here is an example of a patient that presents with an acute inferoposterior MI. Note the STEMI in the inferior leads and the deep ST depression in V1-V2. This patient went urgently to the cardiac catheterization laboratory with an acute in stent thrombosis of a proximal RCA stent. The patient suffered a right ventricular infarction as well.

Septal MISeptal involvement is traditionally associated with involvement of leads V1 and V2. Here is an example of a patient who presented with an anteroseptal MI with evidence of STEMI in V1-V2. This patient had an acutely occluded proximal LAD in the setting of severe 3 vessel disease: