88 year old female CC: Chest pain – Conclusion

This is the conclusion to 88 year old male CC: Chest pain.

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

This ECG shows acute STEMI in the presence of left bundle branch block.

It's also an excellent example of the value of using "excessive discordance" to identify acute STEMI in the presence of left bundle branch block.

For a more extensive discussion of this topic see:

Excessive discordance as a marker of acute STEMI in LBBB

First, let's see if we can make the case for acute STEMI using Sgarbossa's original criteria.

As a refresher, here are Sgarbossa's criteria to identify AMI in the presence of LBBB

1.) ≥ 1 mm of concordant ST-elevation (in the same direction as the majority of the QRS complex) in at least one lead
2.) ≥ 1 mm of ST-depression in lead V1, V2 or V3
3.) ≥ 5 mm of discordant ST-elevation (opposite the majority of the QRS complex) in at least one lead

According to the original scoring algorithm, the more of these criteria that are met, the higher the probability of AMI.

 

So, let's apply these criteria to this case.

Do we see ST-elevation that is concordant with the majority of the QRS complex in at least one lead?

This criterion appears to be met in lead II.

Do we see ST-depression in leads V1, V2 or V3?

Possibly. I bring up data quality so often on this blog that I probably sound like a broken record, but it's rare that I run a case study where we don't have to compensate for poor data quality in one way or another. In this case it appears that ST-depression may be present in lead V1.

How about discordant ST-elevation = or > 5 mm?

This finding is absent on this 12-lead ECG. However, it doesn't really matter because this finding is (by far) the least specific of Sgarbossa's criteria. It's the least specific because it doesn't take into account the depth of the S-wave (rule of proportionality).

In other words, the deeper the S-wave, the greater the ST-elevation, and this is normal.

That's why we use the modified criterion proposed by Stephen Smith, M.D. (Dr. Smith's ECG Blog).

Rather than look for ST-elevation that is = or > 5 mm, we look for ST-elevation that is > than 0.2 (or 1/5) the depth of the S-wave!

To put this in a quick "rule of thumb" for you, for every 5 mm of S-wave depth, we allow 1 mm of ST-elevation.

Or, you can break out the calipers and calculate the ST/QRS ratio.

Let's apply the modified criterion to this case.

Do we see any leads with a ST/QRS ratio > 0.2?

We certainly do (and it's not even close).

So, lead II meets one of Sgarbossa's original criteria (concordant ST-elevation = or > 1 mm) while leads III and aVF meet Smith's modified criterion (ST/QRS ratio > 0.2).

This is more than enough evidence to call this an acute inferior STEMI in the presence of LBBB.

But we aren't finished yet!

Smith et al. discovered that "excessive discordance" works for positive and negative QRS complexes!

With this in mind, do we see "excessive discordance" anywhere else in this ECG?

Yes we do! Lead aVL shows ST-depression that is "excessively discordant" with the QRS complex.

Is lead aVL reciprocal to leads II, III and aVF?

Yes it is.

Point, game and match.

BTW, I also made the calculations for lead V4 because it looked close to me.

It was close, but no cigar. So take a good look at lead V4! This shows close to the maximum ST-elevation that is permitted for a QRS complex of this size.

Once you train your eye it's much easier to spot excessive discordance!

See also:

80 year old male CC: Chest pain

58 year old female CC: Chest pain

2 Comments

  • always like seeing these since they’re not super common.

  • Vicki says:

    I find these fascinating, b/c I used to be an ECG Technician before I started working in Emergency Medicine. But when you do in-hospital ECG’s, at least when you did them in 1999, 2000 and 2001, the doctors did all the readings. All *I* had to do was record the heart’s activity. The patients would always ask me to read and interpret it while I had the leads on their bodies.
    I couldn’t do that for two reason, one of which is obvious. Most of the patients would move around even when I told them not to, and I’d have to tell them again. You can’t get an accurate reading when they keep moving parts of their bodies around. The other reason was that none of the doctors wanted us making interpretations of the ECG’s. It seemed like they had bees in their bonnets about us interpreting anything, even though most of us were cardiac technicians.
    I’m glad I didn’t have to tell the patient what was happening on the ECG monitor. It can’t be easy to hear that you’re in A-Fib which, in this case, the patient was not severe; but when we told the doctor, he acted as if he didn’t even care.
    My partner was shocked out of her mind by his response. I just thought he must be crazy. Or burned out.

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EMS 12-Lead

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Comments
Kevin
44 year old male CC: Palpitations
Why on earth would you risk VF, by giving Adenosine to rule out rhythms.. This is dangerous, and foolish. There might be a slight chance that this is WPW.. You might as well just give him Cardizem, they are both AV nodal blockers... I don't know why the AHA even added this stupid idea..
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Vince DiGiulio
The 360 Degree Heart – Part II
It is standard practice in electrocardiography to label the first 90 degrees counter-clockwise from "zero" that way. When you see a patient with "left axis deviation" you'll see that their measured QRS axis is somewhere between -30 and -90 degrees. Imagine if you saw someone with a mean QRS axis at 5 degrees. Now imagine…
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Bryan
The 360 Degree Heart – Part II
I don't understand why (-)III and aVL are be labeled -60 and -30 degrees instead of 300 and 330 degrees?
2014-10-21 13:43:29
The 360 Degree Heart – Part II | EMS 12 Lead
The 360 Degree Heart – Part I
[…] first post in our “360 Degree Heart” series attempted to visualize how the different frontal plane […]
2014-10-21 12:50:56
Eric Strong
Axis Determination – Part VI
This is a great discussion of axis determination. One minor suggestion: I think it's potentially misleading to refer to an axis between 0 and -30 as "physiologic left axis deviation", since "axis devitation" implies deviation from normal, and axes between 0 and -30 are perfectly normal, (depending on age and body habitus). It may be…
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