ECG Features of Anterior STEMI
Show NB: The magnitude of reciprocal change in inferior leads is determined by the magnitude of ST elevation in I and aVL (as these leads are electrically opposite III and aVF), and hence may be minimal or absent in anterior STEMIs that do not involve high lateral leads. Clinical Relevance of Anterior Myocardial InfarctionAnterior STEMI usually results from occlusion of the left anterior descending artery (LAD). Anterior myocardial infarction carries the poorest prognosis of all infarct locations, due to the larger area of myocardium infarct size. A study comparing outcomes from anterior and inferior infarctions (STEMI + NSTEMI) found that compared with inferior MI, patients with anterior MI had higher incidences of:
In addition to anterior STEMI, other high-risk presentations of anterior ischaemia include left main coronary artery (LMCA) stenosis, Wellens syndrome and De Winter T waves. Patterns of Anterior InfarctionThe nomenclature of anterior infarction can be confusing, with multiple different terms used for the various infarction patterns. The following is a simplified approach to naming the different types of anterior MI. The precordial leads can be classified as follows:
The different infarct patterns are named according to the leads with maximal ST elevation:
NB: While these definitions are intuitive, there is often a poor correlation between ECG features and precise infarct location as determined by imaging or autopsy. For an alternative approach to the naming of myocardial infarctions, take a look at this 2006 article from Circulation. Clinical PearlsOther important ECG patterns to be aware of:
ECG ExamplesExample 1Hyperacute Anteroseptal STEMI:
Hyperacute Anterior STEMI:
A ECG of the same patient taken around 40-50 minutes later:
Extensive Anterolateral STEMI (acute):
Extensive Anterior STEMI (acute):
Prior Anteroseptal / Lateral MI
Extensive anterior MI (“tombstoning” pattern)
Anterior-inferior STEMI
Prediction of the Site of LAD OcclusionThe site of LAD occlusion (proximal versus distal) predicts both infarct size and prognosis.
[This great diagram was originally featured on The Radiology Assistant – follow the link for a more detailed review of coronary artery anatomy.] Territories
Occlusion proximal to S1Signs of basal septal involvement:
Occlusion proximal to D1Signs of high lateral involvement:
In the context of anterior STEMI, ST elevation in aVR of any magnitude is 43% sensitive and 95% specific for LAD occlusion proximal to S1. Right bundle branch block in anterior MI is an independent marker of poor prognosis; this is due to the extensive myocardial damage involved rather than the conduction disorder itself. More ExamplesExample 8This patient’s ECG shows several signs of a very proximal LAD occlusion (ostial LAD occlusion septal STEMI):
This patient came in post VF arrest and was taken straight to the cath lab where he was found to have a complete ostial occlusion of his LAD. Example 9Acute anteroseptal STEMI with STE maximal in V1-4. The following signs of proximal LAD occlusion are present:
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ECG LIBRARYElectrocardiogram Ed BurnsEmergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |
Robert ButtnerMBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner What is an anterior wall myocardial infarction?An anterior wall myocardial infarction occurs when anterior myocardial tissue usually supplied by the left anterior descending coronary artery suffers injury due to lack of blood supply.
How do I know if I have anterior wall MI?Anterior myocardial infarction is associated with a decrease in blood supply to the anterior wall of the heart. Classification of anterior myocardial infarction is based on EKG findings as follows: Anteroseptal – ST-segment elevation in leads V1 to V4. Anteroapical (or mid-anterior) – ST-segment elevation in leads V3- ...
What are 4 signs of myocardial infarction?What are the symptoms of heart attack?. Chest pain or discomfort. ... . Feeling weak, light-headed, or faint. ... . Pain or discomfort in the jaw, neck, or back.. Pain or discomfort in one or both arms or shoulders.. Shortness of breath.. Is anterior infarct a heart attack?Overview. An anterior myocardial infarction (MI) is a heart attack or cessation of blood flow to the heart muscle that involves the anterior side of the heart. An anterior MI is characterized by the presence of ST elevation in the anterior leads V3 and V4.
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