The importance of new ST-segment depressions (STD) and/or T wave inversions (TWI) in lead aVL have not been emphasized or well recognized across specialties. Computer-assisted ECG readings typically report these findings as normal or nonspecific.
There is growing evidence that changes in lead aVL are abnormal, and that paying attention to that lead can be clinically useful. Reciprocal changes presenting as STD or TWI in lead aVL may be indicative of a significant coronary artery lesion and can sometimes be the only ECG manifestation of acute MI.
STD in lead aVL is considered a sensitive marker for early inferior STEMI, and has been shown to help differentiate STEMI from pericarditis. Another recent retrospective study suggests that TWI in aVL might be associated with significant LAD lesions.
Bottom Line: Paying close attention to subtle changes and abnormalities in lead aVL may help in early identification and initiation of therapy for patients who are having an acute MI.
References
Hassen GW, Costea A, Smith T, et al. The Neglected Lead on Electrocardiogram: T Wave Inversion in Lead aVL, Nonspecific Finding or a Sign for Left Anterior Descending Artery Lesion?. Journal of Emergency Medicine. 2014;46(2):165–170.
