EMergucate - Posted on January 16, 2016 - By Anand Senth
"Several pieces of gold in the FOAM world from doctors Stephen Smith and Amal Mattu have highlighted the importance of ST changes in ECG lead aVL for diagnosing and excluding inferior and lateral STEMIs.
aVL as a high lateral lead is the area of the heart electrically opposite to the the inferior leads, in particular lead III. Consequently ST depression/T wave inversion in aVL may be a reciprocal change for an inferior STEMI … and vice versa.
- ST depression in aVL distinguishes inferior STEMI from pericarditis
- ST depression in avL may precede and predict inferior STEMI
- Subtle ST elevation in aVL may represent high lateral STEMI
Take home messages:
- The ECG is proportional. Small ST/T wave changes in the limb leads such as aVL and III can be significant,
- When there is any ST elevation in the inferior leads, look closely at aVL.Reciprocal ST depression/T inversion can confirm inferior STEMI and differentiate from other causes of inferior ST elevation such as pericarditis and early repolarisation
- ST depression/T inversion on its own in aVL may precede and predict an evolving inferior STEMI – get serial ECG’s!
- ST elevation in aVL and I by themselves can indicate a high lateral STEMI especially with inferior reciprocal changes. Look closely for subtle ST elevation in aVL and I and actively seek out any inferior reciprocal changes that may provide early confirmation of high lateral STEMI.
If ever in doubt or suspicious about an ECG, particularly in a patient with potentially concerning symptoms, keep the patient for a period of observation, do serial ECG’s, consider troponins and consult someone with more experience/expertise."
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EEM 2015: Amal Mattu’s ECG trick of the trade to predict STEMIs!
Early Reciprocal Changes in aVL