Understanding aVR ST Elevation in Myocardial Infarction
ST elevation in lead aVR during an acute myocardial infarction (MI) is a critical indicator. It typically suggests a high-risk situation involving significant proximal coronary artery blockage.
Diagnosing Thrombosis Location
Lead aVR reflects electrical activity from the right shoulder perspective. ST elevation in this lead, especially when greater than 1 mm, often signifies injury to the septum or left ventricle caused by occlusion in a major proximal artery supplying these areas. The most common culprits are:
- Left Main Coronary Artery (LMCA) occlusion: Affects the entire left ventricle.
- Proximal Left Anterior Descending (LAD) artery occlusion: Affects a large anterior and septal territory.
These proximal occlusions lead to extensive myocardial damage and are frequently associated with ST elevation in aVR, sometimes accompanied by reciprocal ST depression in other leads like I, aVL, V4-V6.
Occlusions in the right coronary artery (RCA) or left circumflex artery (LCx), or more distal occlusions of the LAD, are less likely to present with prominent ST elevation specifically in lead aVR as the primary finding.
Therefore, given the ST elevation > 1 mm in lead aVR in a patient with acute MI, the likely localization of thrombosis is in the left main or proximal LAD.
Important Questions from Ischemic Heart Disease
- An elderly-man with history of Diabetes mellitus and Coronary Artery Disease comes for follow-up, with complaints of muscle pains. Which one of the following drugs could be the most likely cause?
- All of the following are indications for treadmill testing/exercise-testing EXCEPT:
A 60-year-old man comes to emergency with history of chest pain, which is acute onset. The ECG shows ST depression and T waves inversion. Cardiac biomarkers in blood are not elevated. What will be the appropriate management?
- Which one of the following is not a differential diagnosis of ST segment elevation in ECG?
- A 50-year-old man reports to Emergency with breathlessness, palpitations and acute chest pain. On auscultation, there is systolic murmur at apex and ECG shows ST elevations in anterior chest leads. Which one of the following would be the next choice of investigation ?
