Wednesday, June 17, 2015

Early Repolarization, Anterior MI, or Other?

A 30 something presented with atypical chest pain.

Here is the ECG:
--There is huge ST elevation in V2 and V3, approximately 5 mm.
--There is some ST elevation in aVL with some minimal reciprocal ST depression in III
--There is a small q-wave in V4.
--There are also large S-waves in I and II, and a large R-wave in V1, suggesting right ventricular hypertrophy


It is risky to apply the early repol vs. LAD occlusion formula when there are other indications that this may be MI, such as 1) Q-wave in V4 and 2) STE in aVL with STD in III.  However, when I saw this (I did not take care of the patient), I thought this "looked" like early repol, and I did apply the formula:

STE 60 V3 = 5 mm
QTc = 411 ms
R-wave amplitude in V4 = 25 mm

Formula value = 22.079.  This is very low.  Less than 22 is about 97% sensitive for LAD occlusion.

This is very low.  Serial ECGs were recorded and they remained the same.  The patient ruled out for MI and all ECGs were stable.

Unfortunately, no echo was done to assess for RV hypertrophy.

Learning Points

1.  Early repolarization can have Scary ST elevation
2.  Pretest Probability is Critical.  Here, the low pretest probability was an important factor in this decision: in a young patient with atypical pain, scary ST elevation is much less likely to be due to ischemia.





13 comments:

  1. Hi Dr Smith,

    Could these clinical presentation and ECG tracing besides patient's age also suggest hypertrophic obstructive cardiomyopathy? I'm specifically referring to the high R-wave voltage in V2 and both R-wave and S-wave voltages in V3.

    Olivier.

    ReplyDelete
  2. Hi Dr Smith,

    Could these clinical presentation and ECG tracing besides patient's age also suggest hypertrophic obstructive cardiomyopathy? I'm specifically referring to the high R-wave voltage in V2 and both R-wave and S-wave voltages in V3.

    Olivier.

    ReplyDelete
  3. Mehmet K. ÇelenkJune 17, 2015 at 3:54 PM

    Thank you very much. Another reasuring fact is: We have a healthy amount of R amplitude in V1-3.

    ReplyDelete
    Replies
    1. Definitely. My formula measures R-wave amplitude in V4 and we found in our research that using that one lead was sufficient. But usually the amplitude is high in all of them.
      http://www.annemergmed.com/article/S0196-0644(12)00160-6/pdf
      Thanks,
      Steve Smith

      Delete
  4. F = 22.079 ... 97% sensitive for LAD occlusion = lapsus ?

    Al

    ReplyDelete
    Replies
    1. Al,
      What is "lapsus"?
      Steve Smith

      Delete
    2. "Lapsus" is a term generally used in French-speaking countries and could be translated by 'slip' as in 'slip of the tongue' when the argument is oral. I think, in this case, Alswiss seems to point out that the above mentioned assertion might be a typo.

      Hope that helps ! And thanks again for your blog.

      Olivier.

      Delete
    3. I think he's asking if you meant "specific" instead of "sensitive."

      Delete
    4. Ah. No, it is not a slip of the tongue. 97% of LAD occlusions were either obvious, or had a formula value is > 22.0. Thus, I mean that at a cutoff of 22.0, the formula is 97% sensitive.

      Delete
  5. Hi doc,
    Isn't that RSR' wave in V1 ?

    ReplyDelete
    Replies
    1. Indeed it is. But not quite RBBB, or even incomplete RBBB.

      Delete
  6. Hi,

    I was just wondering, isnt a value greater than 23.4 is sensitive and specific for LAD occlusion? What about the 22 value?
    Thank you.

    ReplyDelete
    Replies
    1. 23.4 is the most accurate cutoff. But it still misses some. A value of 22.0 is significantly more sensitive but with less specificity.

      I am not comfortable pronouncing a case as "no LAD occlusion" unless < 22.0. But I certainly would not activate the cath lab on a value < 23.4 without more supporting evidence, (serial ECGs, echo, high pretest probability, etc)

      Delete

Recommended Resources