Standardized STEMI Identification Assessment

[Christopher]

One of them was a mis click if that matters

For the most part, the ones I missed, I think I rushed through. Half of them were very obvious looking back. The other half... Very,very subtle, so.... I guess there's no middle ground? Haha

I always tell my students when I grade a multiple choice exam that I can't differentiate between a mistaken answer and an incorrect answer, hence we only cover questions that more than 25% of the class missed.

"Subtle" is only because our guidelines for STEMI are not based in reality. Your heart has no idea what a millimeter is (for all we know it still uses English units), so why on earth do we think 1mm+ in 2+ contiguous leads is going to be the end-all-be-all of STEMI identification?

Besides, those criteria were developed in the age of thrombolytics and by "developed" I mean chosen rather arbitrarily as there have not been any trials to determine the optimal cutoffs. You can tell they're not grounded in reality when they have these exceptions like ">1.5mm in V2 and >2mm in V3 for yada yada yada", because they do not account for proportionality or normal variants.

If Tom only got an 83%, I feel slightly better with my score

You can score a respectable 70% and have a horrible number of false positives. Accuracy is not nearly as important as a reasonable sensitivity/specificity, and nowhere near as important as an item-by-item review of what you missed and why.

 

[Christopher]

Thank you to everyone (n=35) who has taken this so far!

This group was mostly paramedics, but included RN's, PA/NP's, technicians, and med students. The comfort level was right in the middle (4 out of 7), and most read roughly 3-5 ECG's per week. Combined accuracy of 68%, false positive rate of 12%, and a false negative rate of 21%.

The previous cohort of paramedics (n=16) who took this for me was local and skewed towards a higher comfort level (6 out of 7, "near expert"), and skewed towards more ECG's read per month. They had an accuracy of 77%, false positive rate of 5%, and a false negative rate of 18%.

In both cohorts I've run there is an increase in accuracy, and a decrease in FP and FN rates as you increase the number of ECG's you read in a month. Read more ECG's!

The original McCabe study looked at physicians of multiple levels (n=85), most of whom had a lot of ECG experience. Their combined accuracy was 70%, with a 7% false positive rate, and a 23% false negative rate.

What I've noticed is while the accuracies are roughly similar (excluding my local cohort), which ECG's the groups disagreed upon were quite different.

Paramedics think these ECG's are easy, and overwhelmingly get it right while the MD's miss them: subtle IWMI with recip change in aVL, hyperacute AWMI with recip change in aVL, anteroseptal MI with recip changes inferiorly.

Likewise, this cohort and even the more accurate local group of medics had problems with these ECGs when compared to the MD's: IWMI w/ tachycardia, Wellen's syndrome (although I'm sure this is rarely associated with "acute" for EMS).

These ECG's it seemed our group had the same problems the MD's had (respondents combined <50% correct): subtle lateral wall MI, posterior MI w/ AVB, subtle lateral wall MI, subtle inferior wall MI.

Key takeaways:

1. Read more ECG's
2. Ischemic ST-depression does not localize! Localized ST-depression is a reciprocal change until proven otherwise.
3. Your heart has no idea what a millimeter is, do it a favor and forget absolute criteria; allll things in proportion!
4. Level of education does not seem to matter as much as ECG experience; medic vs MD who cares!

 

[teedubbyaw]

Thank you, Christopher. Don't stop sharing your knowledge on these forums!

 

[socalmedic]

I tried doing this at work and found a bug/glitch. I kept getting this after the basic demographics page.

"Script function not found: doPost"

Windows 7, IE 9 version 9.0.8112.16421 update 9.0.23. DSL 3Mbt down.

 

[Christopher]

I tried doing this at work and found a bug/glitch. I kept getting this after the basic demographics page.

"Script function not found: doPost"

Windows 7, IE 9 version 9.0.8112.16421 update 9.0.23. DSL 3Mbt down.

Interesting. It runs under Google's Caja sandbox, which supposedly works on IE9+ but perhaps not.

I'll look into it!

 

[chaz90]

Well. I did a remarkably poor job on that bad boy. Good information though!

 

[Smash]

Would not work on Chrome running on Android device. Would go through the quiz, would not display results.

Just curious regarding Wellen's for this, are you considering this a STEMI equivalent or sub-acute/reperfused? Our cath labs don't want us activating for Wellen's.

 

[Christopher]

Would not work on Chrome running on Android device. Would go through the quiz, would not display results.

If you tell me roughly when you took it I can PM you your results.

Just curious regarding Wellen's for this, are you considering this a STEMI equivalent or sub-acute/reperfused? Our cath labs don't want us activating for Wellen's.

That's a great question, one that is better left to the System itself. Wellen's is no more or less a coronary artery occlusion event than your traditional STEMI, and perhaps even more insidious as it can be mistaken for angina. The point of this assessment was to see how well folks perform at the identification of coronary artery occlusion. Whether your system wants you to activate on Wellen's is another question entirely, one of sensitivity and resource usage!

 

[Clare]

Sensitivity 67 %
Specificity 75 %
Positive Predictive Value 84 %
Negative Predictive Value 53 %

Thanks for this; it was very informative and interesting.

I am OK with run of the mill STEMIs and other such ST abnormalities but I get lost in the more complex stuff like STEMI in the presence of LBBB.

While probably a lame endpoint, when in doubt, refer to hospital with a cath lab!

 

[Brandon O]

Just curious regarding Wellen's for this, are you considering this a STEMI equivalent or sub-acute/reperfused? Our cath labs don't want us activating for Wellen's.

I griped about this too, just because definitionally it's not a STEMI. (Of course, if we're getting out the dictionary, neither is an isolated posterior, but I hope you take my point.) Just one of those lawyer things.

 

[blindsideflank]

Your accuracy was: 72 %
Your sensitivity was: 58 %
Your specificity was: 100 %
You had 0 false positive(s) and 10 false negative(s).


weird, if anything I would have said i miss more positives than I falsely diagnose in the field

 

[STXmedic]

As soon as I get out of the hospital, I'll be taking this.

 

[Christopher]

I griped about this too, just because definitionally it's not a STEMI. (Of course, if we're getting out the dictionary, neither is an isolated posterior, but I hope you take my point.) Just one of those lawyer things.

I swear we need a better phrase for this...I still get crap for "well that's not 1 millimeter". Perhaps Code OOYHLMFHBCOMCA: one of y'all hospital lookin' monkey flippers had better check out my coronary arteries?

It's unfortunate that the term we use is based on an insensitive criteria.

 

[Christopher]

Your accuracy was: 72 %
Your sensitivity was: 58 %
Your specificity was: 100 %
You had 0 false positive(s) and 10 false negative(s).


weird, if anything I would have said i miss more positives than I falsely diagnose in the field

This dataset has a number of subtle coronary artery occlusions, those which serial ECG's may pick up. Perhaps they represent conditions where you wouldn't activate off the initial ECG.

 

[Smash]

If you don't mind Christopher, I would like to put a link up to this on my blog.

 

[Christopher]

If you don't mind Christopher, I would like to put a link up to this on my blog.

Feel free bud, thanks!

 

[Chimpie]

Just put a link to this thread up on our Facebook page. Hopefully you'll get a few more participants.

 

[socalmedic]

Just put a link to this thread up on our Facebook page. Hopefully you'll get a few more participants.

we have a Facebook page?

 

[Chimpie]

we have a Facebook page?

Yep, and Twitter. Links below, but let's try to stay on topic. Thanks!

 

[TomB]

I took the test again with the idea that: 1.) there was clinical correlation with typical signs/symptoms of ACS. 2.) that the standard was "do I think it's an occluded artery" with the understanding that the ECGs were taken from an academic paper on the topic.

That's a different standard from "would I call a Code STEMI from the field" since many of them don't meet our Code STEMI criteria (which I designed).

So in the "risk free" testing environment I got one false positive and one false negative. The false positive was probably Wellens (I wasn't sure how the test would score Wellens) and the false negative was reportedly acute anterior STEMI which looked to me like ventricular aneurysm or LVH with strain.

Anyway, if you haven't taken the test in a while I would take it again! Christopher has made some improvements. It will rate you against other health care disciplines, show you which ones you got wrong, etc. (If it did that before I missed it).

Robert Simpson from AmboFOAM blogged about it, too (is that one of you?)

http://ambofoam.wordpress.com/2014/06/22/so-you-think-you-can-spot-a-stemi/

Tom