Sunday, November 13, 2016

Paper published: Terminal QRS distortion not found in any ECG of Early Repolarization

This ECG comes from a 30-something with chest pain. 

Is it early repolarization?  Or is it LAD occlusion?  The paper below helps to make this diagnosis.

See at bottom for full explanation









This paper is now published

Daniel Lee, Brooks Walsh, Stephen W. Smith.  

Terminal QRS distortion is present in anterior myocardial infarction but absent in early repolarization.

Volume 34, Issue 11, November 2016, Pages 2182–2185

http://www.ajemjournal.com/article/S0735-6757(16)30545-9/abstract


Here I show it again:





So, the only plausible reasons for ST elevation are 1) LAD occlusion or 2) Early Repolarization.  One might be tempted to apply the formula that helps to differentiate the two.  However, when we studied these ECGs, we excluded patients with features that made STEMI "obvious," or at least not subtle.  These features included Q-waves and Terminal QRS distortion.  In this case, the Q-waves do not make it an obvious MI, but the QRS distortion does:
  
QRS Distortion was defined by Birnbaum as: "Emergence of the J point ≥50% of the R wave in leads with qR configuration, or disappearance of the S wave in leads with an Rs configuration)"  (from this paper by Birnbaum).    


I would add to this: if there are distinct J-waves in these leads, then early repolarization is still a likely possibility.  In this case, there are no distinct J-waves in V2 or V3 (although there is a small one in V4)

Thus, this ECG should be thought of as diagnostic of anterior STEMI.  If the formula had been used, then the value would have been [1.196 x 3.5]+[0.059 x 402]–[0.326 x 17] = 22.362 (which is less than 23.4 and thus consistent with early repolarization).  The formula would have given a false negative, because this was an LAD occlusion.  



Learning Point:

When there is Terminal QRS distortion (absence of BOTH an S-wave and a J-wave in EITHER of leads V2 or V3, it is not early repolarization).  When the differential diagnosis only includes early repol and LAD occlusion, then LAD occlusion is strongly favored.

Here is another case:

1 comment:

  1. Congratulations! Another step forward to defeat BER.

    ReplyDelete

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