T Wave Inversion in AVL Could be Important – Don’t Always Rely on ECG Computer Diagnosis

In an acute coronary syndrome situation in emergency, ALV inversion had significance.  84.8% of patients had > 50% obstruction of the mid-segment left anterior descending (MLAD) artery.  In subjects with >50% obstruction, 84.9% had T wave inversion in one other lead – mostly lead I. In subjects with no significant obstruction, finding another lead inverted was only half as likely (42.1%).  It had a 76.7% sensitivity and 71.4% specificity.

J Emerg Med. 2013 . [Epub ahead of print]
The Neglected Lead on Electrocardiogram: T Wave Inversion in Lead aVL, Nonspecific Finding or a Sign for Left Anterior Descending Artery Lesion?
Hassen GW, Costea A, Smith T, Carrazco C, Hussein H, Soroori-Rad B, Vaidian S, Seashore J, Alderwish E, Sun W, Chen A, Simmons B, Usmani S, Kalantari H, Fernaine G.
http://www.ncbi.nlm.nih.gov/pubmed/24286713

• Excluded those with LVH or BBB’s
• Leads I, V5 and V6 were given special attention
• “Of the 106 patients who had MLAD lesions of > 50%, 90 (84.9%) had TWI [T wave inversion] in lead aVL and one additional lead, mostly lead I.”
• “Excluding those patients with LVH or BBBs from the 106 patients who had MLAD lesions of > 50%, 37 patients (34.9%) had isolated TWI in lead aVL, and of the 19 patients who had MLAD lesions of < 50%, 6 (31.6%) had isolated TWI in lead aVL.
• Conclusion: T Wave inversion in lead aVL might signify a mid-segment LAD lesion
• They quote a prior study finding the odds ration of a left anterior descending lesion being present with isdolated T wave inversion in AVL was at odds ratio 2.93

Comment – they point out this will be missed by computer diagnosis so, in the right clinical setting, needs to be watched for..

They mention couple syndromes that are easily missed by computer:
Brugada syndrome – half the time, the cause of sudden death in structural heart disease as is associated with V. Tach:
– prolonged pr interval in most
– Right BBB pattern
– St elevations V1-3

Wellens’ sign  – steep T wave descent in V leads – suggests critical stensois Left anterior descending artery (The Widow maker) – and requires immediate cath even if enzymes normal…

Guess you can’t always rely on ECG computer for diagnosis….