Is this a mimic or the real thing? – Discussion

This is the follow-up discussion to:

Tweet about ECG leads to mystery – is this a mimic or the real thing?

Let’s take another look at the 12-lead ECG.

This is a very suspicious ECG and must be considered acute inferior STEMI until proven otherwise.

This was my initial gut feeling about this ECG and I confirmed it with one of the smartest electrocardiographers I know (Stephen Smith, M.D. from Dr. Smith’s ECG Blog).

In fact, he discussed this exact type of ECG in his recent appearance on the EMCrit podcast.

EMCrit Podcast 42: A phD in EKG with Steve Smith

Let’s take another look at the ECG marked up so I can point out the key features that make this ECG so suspicious.

In the first place, the ST-elevation is limited to a particular set of contiguous leads (the inferior leads).

When a patient is experiencing acute inferior ST-elevation myocardial infarction, there is almost ALWAYS some type of reciprocal finding (ST depression, T-wave inversion, or both) in lead aVL.

If this is a mimic of acute STEMI, it’s one of the best I’ve ever seen, because of the inverted T-wave. In fact, I’m certain that’s why the computerized interpretive statement is calling this a STEMI.

In addition, the R/S ratio in lead V1 makes me suspicious (although it would be more suspicious in an older adult).

I’m also not pleased with the appearance of the Q-waves in lead III. Granted, lead III is a bit “quirky” but as you can see, these little coincidences are adding up and as Tomas Garcia M.D. is fond of saying, one must “consider the company” any ECG abnormality keeps.

This case demonstrates why a good story is very important when screening people for acute STEMI.

As Dr. Smith indicated in regard to this case, a lower pre-test probability changes things and makes some type of localized pericarditis much more likely (remember the patient has a low-grade fever).

However, it does not eliminate the possibility of acute inferior STEMI, and an ECG abnormality like this cannot be blown off. The way to handle it is a stat bedside echocardiogram to look for wall motion abnormalities that would indicate acute STEMI.

(Editor’s note: this ECG is not typical for benign early repolarization in spite of the fact that the patient is a young African American male).

8 Comments

  • Troy says:

    So if this kid has cerebral palsy and is a 4-2-4 glascow what would make someone think he would present normally? I would have at least called and told the doc. Talked to our MD and she said even with a bedside US she wouldn’t hesitate sending him to cath with this EKG

  • Tom B says:

    Troy –

    A stat bedside echo seems prudent to me. It takes ECG seriously but also stands to prevent this young man from being subjected to an unnecessary surgical procedure. It’s an awesome tool for the emergency department!

    Tom

  • Too bad we don’t have the outcome data for this ECG.

    I have noticed frequent counterclockwise Z-axis rotation with younger adults. It does add more evidence towards STEMI though.

  • Troy says:

    Tom-

    I don’t know too much about bedside echo in MI especially STEMI except that I know they do it. If it is a STEMI, will a bedside echo show wall abnormality all the time? The MD I talked to was thinking worst case

  • Troy says:

    I guess what I’m asking is bedside echo 100 percent or close to specificity for MI?

  • Tom B says:

    That’s a fair question, Troy. I’ll ask Dr. Smith.

  • Dave B says:

    also, just to add 2 cents… Dr. Mattu has lectured extensively on upright T waves in V1… if they are presumed new, or greater than or equal to the height of the T wave in V6, it is also very suspicious for MI… Tom, i don’t know if this is why you have V1 “in the box”..

  • Tom S says:

    Very Suspect ECG, the patient is not of the demographic of a 'fit & healthy' 19y/o with his hx of Diabetes & HTN and certainly has his risk-factors for AMI.
    He does have a reassuringly short QTc, but I would not be hasty to rule out AMI by any stretch
     
    (UK Paramedic)

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