We just published this online in the American Journal of Emergency Medicine:
ST depression in lead aVL differentiates inferior ST-elevation myocardial infarction from pericarditis
A couple ECGs: These do not come from the study:
This was a middle-aged man with chest pain (Figure A):
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| There is diffuse ST elevation, but there is no ST depression in lead aVL Diagnosis? |
The above is a case of a patient with chest pain who did not have MI. This was early repolarization.
Figure B. Here is a 40-something with chest pain  |
| What is it? |
The above (figure B) was a proven occlusion of an artery supplying the inferior wall (in this case, it was a distal occlusion of an LAD that wrapped around the apex and supplied the inferior wall.
Notice the minimal (less than 1 mm) ST elevation in III. But there is clearly some ST depression in aVL. This makes it all but diagnostic of inferior MI.
Figure C:
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| What is this? |
Figure C above is proven pericarditis.
Here is the ECG 2 days later (Figure D):
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Pericarditis later still
CONGRATS on publication of your article Steve! NICE to get a “formal study” out there on this important subject! I’d just add 2 points: i) In the ECG shown in Figure A — there IS T wave inversion, but NO ST depression (as you emphasize). It is key to be aware of the difference. Isolated T wave inversion may be normally seen in lead aVL, especially when the QRS is predominantly negative (as it is in Fig. A). So Figure A truly supports your emphasis that this is not a stemi tracing.
ReplyDeletePoint ii) — The easiest way I’ve found to explain the concept of reciprocal ST-T depression is to think of a “mirror-image”. Leads III and aVL are almost “magic” in how with acute occlusion, the two leads so often manifest a mirror-image of the other. We see this in Figure B — for which the tiny amplitude complex in aVL manifests an ST-T wave that truly looks (shape-wise) like the mirror-image of the ST-T wave that we see in lead III.
THANKS again for your work on this subject Steve!
Dear Smith
ReplyDeletedose the V4 in figure C show terminal QRS distortion? Thanks
Terminal QRS distortion is normal in V4. It is only if it is in either V2 or V3 that I get worried
DeleteDear Smith
ReplyDeleteDo you mean that there is indeed QRS distortion in V4 in figure C? and If I see V4 QRS distortion in other ECG, it is normal?
thanks
Well, it is not really QRS distortion because it is normal to have neither a J-wave nor an S-wave in lead V4. However, even if that were abnormal for V4, this one has a J-wave in V4! So even if V3 looked like V4, it would not be QRS distortion because there is "either a J-wave or an S-wave." in this case there is a J-wave, but no S-wave. So V3 can look like that. Again, V4 can have NEITHER and be normal
Delete