Thursday, June 6, 2013

Activate the Cath Lab?

This 52 year old African American male presented with chest pain that was not clearly typical.  Here is his ED ECG:
There is ST elevation with "coving" (upward convexity) and T-wave inversion.  
The treating physicians were appropriately worried about STEMI and activated the cath lab.  I happened by and saw the ECG and was quite certain that it was Benign T-wave Inversion (BTWI), not STEMI.  The cath lab was de-activated.  A stat echo was done and showed no wall motion abnormality.  The patient was admitted and ruled out for MI.

I was unable to fully explain why I knew this was BTWI.  But below are some factors that I have noticed about BTWI:

First, Dr. K. Wang has shown that it is by far most common in African American males.

1. There is a relatively short QT interval (QTc < 425ms).  (It was 390 ms here.)
2. The leads with T-wave inversion often have very distinct J-waves (as in V4 and V5 here).
3. The T-wave inversion is usually in leads V3-V6 (in contrast to Wellens' syndrome, in which they are V2-V4)
4. The T-wave inversion does not evolve and is generally stable over time (in contrast to Wellens', which evolves).
5. The leads with T-wave inversion (left precordial) usually have some ST elevation
6. Right precordial leads often have ST elevation typical of classic early repolarization (not in this case)
7. The T-wave inversion in leads V4-V6 is preceded by minimal S-waves (as here)
8. The T-wave inversion in leads V4-V6 is preceded by high R-wave amplitude (as here)
9. II, III, and aVF also frequently have T-wave inversion.


--In this case, the ST elevation in also not high (less than the "criteria" of 2 mm in V2 and V3 in men over age 40)
--The T-waves are not upright, so if this is MI as in Wellens' syndrome, the pain should be resolved.  Acute and ongoing occlusion should have an upright T-wave.

Recognizing this requires some experience and seeing many such cases.  Here is a post with several cases of BTWI.

2 comments:

  1. Or when i am not sure if its nstemi, i repeat ecg for tye patient every15mins to look for evolving change of stemi. Wat do u think?

    ReplyDelete