Saturday, September 6, 2014

A 50-something year old with typical chest pain

A middle age male presented with chest pain.  Here is his ECG; there was no previous for comparison:
QTc is 380 ms. There is 3 mm of STE at the J-point in V2 and 2.5 mm in V3.  There is also slight STE in aVL with reciprocal ST depression in III. 

It is a rather scary ECG, very suggestive of proximal LAD occlusion (proximal would include the first diagonal, resulting in high lateral MI with STE in aVL and reciprocal ST depression in III).

What is it?
[There is also an upright T-wave in V1 and larger than the T-wave in V6 (some say this is a sign of STEMI - I have not found that it is a predictive independent variable)]





















I immediately knew when I saw this that is was early repolarization.  How?

First, what are the worrisome aspects?

1) what most catches the eye is the absence of an S-wave in V3.  Normally, this is called "terminal QRS distortion" and is a very good sign of STEMI. However, it is NOT QRS distortion because, even though there is no S-wave, there is a very pronounced J-wave (a wave at the J-point).

2) The STE in aVL and STD in III suggest STEMI, but this is minimal ST deviation, and not enough to prevent use of the LAD occlusion vs. early repol formula (see sidebar excel applet).

With QTc 380
STE at 60 ms after the J-point in V3 = 2.5
R-wave amplitude in V4 = 28
Result = 16.3, which is far less than the cutoff of 23.4

We did serial ECGs and there was no change.  He ruled out for MI with serial troponins.  (Ruling out alone is not proof, however -- This is a GREAT CASE)

The reciprocal relationship between aVL and III should still be bothering some.  Below is an explanation that is further elaborated upon in this post: 

Here is a post on True positive vs. false positive ST elevation in aVL, with illustrative cases

When there is ST elevation in aVL, with reciprocal ST depression in III:

1. Look for these signs of MI:
    a. Absence of J-waves 
    b. Other ST depression
    c. Large T-waves 
    d. Symmetric T-waves
    e. Down-Up T-waves
2. Compare with an old ECG
3. Use ED Echo if available 
4. Use formal Echo 
5. A positive troponin is helpful (a negative one is not if symptoms are of few hours duration or less)

16 comments:

  1. Is there subtle ST elevation in lead I? Up sloping ST segment in V2 - hyper acute?

    ReplyDelete
    Replies
    1. this is early repol, and it can fool you. It can look a lot like STEMI

      Delete
  2. the high amplitude of R wave in V4 and the short QTc in the same lead provided me the clue that this not an MI.

    ReplyDelete
  3. Did you performed an echo to r/o LVH ?

    ReplyDelete
  4. Are U waves present in the chest leads?

    ReplyDelete
    Replies
    1. Yes, but they are normal U-waves. Good observation.
      Steve Smith

      Delete
  5. As a paramedic i would have called this a stemi due to the elivation and pt having chest pain. Treat with NY 0.4mg SL till drip is set up. If pt still has chest pain and BP is above 100/systolic and no relief with NY drip then morphine 2mg.

    ReplyDelete
    Replies
    1. That is great. Best to assume the worst until proven otherwise

      Delete
  6. Sir, without anyother investigation only on the base of ecg can u say that this is not a mi other than early repolarization??

    ReplyDelete
    Replies
    1. It is very difficult and requires lots of experience and expertise. I looked at it and knew immediately that it was not STEMI. Serial ECGs not changing was very supportive. However, I did wake up in the middle of the night and think, "What if I was wrong?"
      Steve Smith

      Delete
  7. What about pericarditis? Looks like diffuse, concave ST elevation without any reciprocal changes

    ReplyDelete
    Replies
    1. With pericarditis, you expect ST elevation in II, V5, V6. It is also much less common than normal variant.

      Delete
    2. And also PR segment depression, which is not here

      Delete

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