Saturday, April 30, 2011

Apparent ST depression in lead III. Is it MI?

A few days ago, I posted this ECG with "inferior" ST depression that was reciprocal to high lateral MI due to a 2nd diagonal occlusion.
Here is the post, with a previous baseline ECG:
Here is a repost of the ECG:
there is minimal but real ST depression at the J-point, in III and aVF.  Lead aVF has J-wave notching, typical of early repolarization, and should have, if anything, a bit of ST elevation (the ST segment on the baseline ECG was actually isoelectric).  The ST depression in III and aVF is reciprocal to real ST elevation of the J-point in lead aVL (and I).

The next day I saw this ECG:
One might say this has the same findings, but if you look closely, the J-point in lead III is isoelectric, as is lead aVF.

I immediately saw this as a normal ECG, but realized that some would see the downsloping in lead III and think that there is ST depression, same as the former ECG.  They are different and the difference is sublte but real.

The second is normal and I sent the patient home with noncardiac chest pain.


  1. The T-waves in the precordial leads are far more impressive in the second ECG. But the QTc appears relatively "tight", R-wave progression is intact, and there is no ST-elevation to speak of.

  2. Yes, the QTc is 385. Precordial leads have early repol.

  3. Not sure if I'm talking myself into this, but is the top ECG a RBBB? and the bottom a LBBB?

  4. Neither are BBB, but the top one has 2 PACs which are aberrantly conducted with an RBBB pattern.