Tuesday, May 24, 2022

A 30-something with Chest pain, elevated troponin, with Subtle ST Elevation and hyperacute T-waves.

A 30-something male presented in the middle of the night with several hours of sharp, non-radiating, left sided chest pain.  It was there earlier, went away, and then returned approximately 1 hour prior to arrival. He is a smoker and has some family history of early MI.  

Exam and vital signs were normal.

Here was the triage ECG:

There appears to be diffuse ST Elevation (II, III, aVF with reciprocal STD in aVL, V3-V6, and lead I, with T-waves that appear to be hyperacute (broad and fat, but on the other hand they have no straightening of the ST segment).  
ST depression and T-wave inversion in V2 suggests posterior OMI.
This is highly suggestive of acute OMI.

Providers were not convinced that this was OMI, so they awaited the first troponin.  The initial high sensitivity troponin I returned 68 minutes after this ECG at 3900 ng/L (quite high, consistent with OMI, NOMI, or other etiology of acute myocardial injury).

Given the young age, they were also suspicious of myocarditis, and ordered a CRP.

The Cath lab was activated.  Here is the report:

Cath lab activation at 3 am by the ED for atypical CP, and elevated troponin with diffuse STT changes.  No angiographically significant obstructive coronary artery disease .

Peak trop at 7 hours was 4646 ng/L

CRP 88 (very high)

Formal Echo the next day:

The estimated left ventricular ejection fraction is 49%.

Cardiac MRI

1) Borderline decreased LV function with small wall motion abnormality involving the apex 

2) Normal dimensions of all cardiac chambers 

3) Patchy areas of myocardial edema. There is also patchy myocardial delayed enhancement with subendocardial sparing, involving the distal anterior wall, distal inferolateral wall and the basal inferior wall. 

Pattern is consistent with acute myocarditis. 

4) Trace pericardial effusion. 

After the fact, this further history was obtained:  

Of note, one week ago he was ill with nausea, vomiting, and diarrhea. He has noticed fevers and chills as well.

Subsequent ECGs??  I would love to have seen the evolution of the ECGs over days to weeks, but unfortunately, no more were recorded.

Learning points:

Sometimes there are false positive ECGs, or at least a clinical scenario and ECG combination that forces an angiogram.  How could such a false positive activation be avoided?  

That is very difficult, because the delays inherent in confirming or rebutting the diagnosis of OMI take a lot of time, and time is myocardium.  

Cases like this are NOT common, and so will not lead to a flood of unnecessary angiograms.  

If suspicion of Non-OMI etiology is high, then emergent formal bubble contrast echo is very useful, but in myocarditis, it usually reveals a wall motion abnormality.

CT coronary angiogram is excellent, but is rarely available outside of business hours, and hardly ever at night.

The initial troponin is often negative in OMI, and even if it were useful, the mean time from presentation to sample collection in MI studies is about 50 minutes, and the time from collection to central laboratory result is at least 30 minutes.  Although the POC troponins that are available at the present time are very inaccurate in the low range and not appropriate for rule out, they can be useful in confirming acute MI (OMI or NOMI) if elevated.   

But they do NOT differentiate between OMI and myocarditis!!

Bottom line: if you don't want to miss OMI, with its attendant significant myocardial loss, then some false positive angiograms are a reasonable price to pay.

See this case:

A Young Woman with Chest Pressure and Subtle, Focal ST Elevation and Depression


MY Comment by KEN GRAUER, MD (5/24/2022):


Insightful case presented above by Dr. Smith! I focus my comment on the fact that the initial ECG in this case manifests LA-LLead Reversal. For clarity — I have reproduced the initial ECG in today's case — and placed what this ECG should look like if the extremity electrode leads were corrected placed (Figure-1). 

Figure-1: Showing the effects of LA-LL Lead Reversal (See text).

It's EASY to overlook lead misplacement — because we do not encounter this entity very often. I highlight this problem in the July 28, 2020 post in Dr. Smith's ECG Blog — in which I include a Table, LINKS to other of our blog posts with examples of lead reversal — and a number of Pearls to facilitate recognizing when the leads are "off".
  • By far — the most common lead reversal is mix-up of the LA (Left Armand RA (Right Arm) electrodes. But this is not the mix-up that occurred in today’s case — because we do not see global negativity (of P wave, QRS and T wave) in lead I (See the February 11, 2020 post).

  • In the July 28, 2020 post in Dr. Smith’s ECG Blog — I cited my favorite on-line “Quick GO-TO” reference for the most common types of lead misplacement, which comes from LITFL ( = Life-In-The-Fast-Lane). Simply put in, “LITFL Lead Reversal” into the Search bar — and the link comes up instantly!

  • The tipoff to LA-LL Reversal in Figure-1 — is that the P wave in lead I is clearly larger than the P wave in lead II (and that is distinctly unusual when there is sinus rhythm).
  • The other, more subtle "tipoff" to LA-LL Reversal — is that in the context of what appears to be hyperacute ST-T waves with predominantly positive QRS complexes in leads I and II — the predominantly negative QRS, which also manifests some ST elevation in lead III just looked "off".

I've become extremely good at recognizing the most common form of LA-RA Lead Reversal — because the global negativity of P wave, QRS complex and T wave that this produces in lead I is never a "normal" finding. I still find it easy to overlook the less common forms of lead reversal — such as the LA-LL Reversal in today's case.
  • Take-Home Message: Remember that with normal sinus rhythm — it is rare indeed that the P wave in lead I will be larger than the P wave in lead II. Next time you see this — Enter "LITFL Lead Reversal" into your internet search bar to remind yourself of what you'll see with the common types of lead reversal.
  • P.S.: For another example of LA-LL Lead Reversal like the one in today's case — Go to the Addendum at the bottom of the page in the August 28, 2020 post in Dr. Smith's ECG Blog. I initially missed that one ...

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