I'm not seeing any STE, I've got inverted T's in the high lateral leads and anterior precordials. Not sure why it claims Acute MI. However, those algorithms are pretty accurate, so I'll run serial 12Ls to see what changes!

Flip that 12-lead over and you got yourself a posterior wall MI.

How can you see a posterior wall mi from a 12 lead.....?

Gah! Nice catch Terry. Looking at V1-V3 again it is clear that could be "posterior STE". Usually I'm looking for larger R waves in those leads and inferior changes.

How about PE? Flipped T's in the precordium fit with that, and we don't have the tall Rs that would support a posterior.

- Ex-medic

How about aVL & V4. Why are we seeing changes in those leads? Besides inversion, what about those T-waves is pathognomic?

You beat me to it, Adam!

One of the most important rules of ECG interpretation applies to this 12-lead. It's something I learned from Tomas Garcia, MD.

"Consider the company it keeps."

One of Dr. Smith's rules also applies, and that's the rule of proportionality.

Consider the high lateral leads I and aVL. Any time you have ST-depression / T-wave inversion in the high lateral leads with a chest pain patient you should be thinking acute inferior STEMI right away and then go about trying to disprove it..

In this case, even though the ST-elevation in leads II, III, and aVF is extremely modest and upwardly concave, it's reciprocal to the ST-T waves in the high lateral leads.

That's a suspicious finding.

Now throw in the ST-depression / T-wave inversion in the right precordial leads V1-V3. Does that "match" acute inferior STEMI?

Yes!

That's what Tomas Garcia, MD means when he says "consider the company it keeps". He means that certain underlying disease processes create specific constellations of ECG abnormalities that "go together" sort of like RAE, right axis deviation, and tall R-waves in the right precordial leads V1-V3 with RVH.

Remember that increased R/S ratio in leads V1 and/or V2 with posterior STEMI are actually reciprocal Q-waves! In other words, they need not be present in order for ST-depression / T-wave inversion to be significant in leads V1-V3.

Tom

Does anyone believe this meets common STEMI criteria?

- ST-elevation of > 1 mm in two contiguous leads
- If ST-elevation is in V1-V3 must be at leas 2 mm

Would you call a STEMI/cardiac Alert?

Adam -

Too much wandering baseline in this ECG to make the call, but my gut feeling is that no, I would not call a STEMI Alert based on this ECG without serial changes.

I would, however, transmit it and request non-PCI hospital bypass if that applied.

Tom

Tom,

I think that you would be doing the right thing. I'd go with UA/NSTEMI on this one.

I also believe that STEMI guidelines should be updated to include dynamic changes. No matter what the pathology is, trending ST/T changes should be urgently transported to a PCI center. But I don't have to tell you this.

Adam -

Don't get me wrong. I think there's an excellent chance the patient has an acute thrombotic lesion in an epicardial coronary artery and might benefit from an emergent cath.

This ECG is suggestive for the reasons I cited but I would not call a STEMI Alert because it does not appear to meet the commonly accepted criteria. That's why I would shore up the diagnosis with serial changes.

Tom

Clearly to the party late, but I'm not calling a STEMI alert on this based on patient presentation, then ECG.
I wonder if this kind of extensive interpretation is turning into the "Mechanism of Injury' of acute cardiac care.
That is meant with the highest of respect to Adam, Tom and all others who are experts in these rules and wave forms, but at what point do I ignore the machine's interpretation and trust my own?

@Happy Medic,

I'm not in either Tom's nor Adam's class when it comes to EKG interpretation, but I frequently ignore the machine's interpretation in favor of my own.

The proprietary Marquette algorithm most of these machines use misses a fair portion of STEMIs - it's fairly good for specificity, but not so much for sensitivity.

And it just flat sucks at recognizing AV blocks.

HM,

at what point do I ignore the machine's interpretation and trust my own?

Good question. I look at the prehospital monitors like this: They are much more likely to over diagnose an AMI than under-diagnose. This may not be a problem for you or your system. The likelihood of catching all STEMI patients is higher. However, the likelihood of over-triaging is higher as well. In many systems this becomes a problem because activating the cath team is expensive.

This is what I do, take it as you will:

If the machine doesn't diagnose ****Acute MI****, I try to prove it wrong by interpreting the findings. I know it probably won't be a STEMI if the machine didn't call it one.

If the machine does diagnose ****Acute MI****, I try to prove it right. I make sure there isn't any artifact, correlate the findings, and beat feet.

If I disagree with the machine in either instance, I will most likely transport to a PCI facility. I will use my serial ECGs, and patient presentation to gauge any further treatment. Calling STEMI Alert is strictly based on the guideline, however calling the doc is always an option.

Hope that made sense. Thanks HM.

Kelly,

I think I have just contradicted your analysis. I believe the machines are more sensitive than they are specific for STEMI.

I wouldn't put myself on the same level as Tom of course. Maybe he can chime in with his thoughts here soon.

Happy Medic wrote:

"I wonder if this kind of extensive interpretation is turning into the "Mechanism of Injury' of acute cardiac care."

MOI is not an extensive interpretation. Quite the reverse. What is expertise if not the ability to engage in a nuanced discussion about a given topic?

"That is meant with the highest of respect to Adam, Tom and all others who are experts in these rules and wave forms, but at what point do I ignore the machine's interpretation and trust my own?"

I occasionally watch the weather forecast but I still look out the window.

In other words, there's a middle ground between relying on the computerized interpretation and ignoring the computerized interpretation.

I consider the computerized interpretation.

Tom

AD is right on the money as far as the GE-Marquette 12SL interpretive algorithm.

It's not particularly sensitive when it comes to diagnosing acute STEMI but it is fairly specific (but far from perfect).

Why? Because the ACC/AHA STEMI criteria is far from perfect! Not to mention the algorithm is highly susceptible to being led astray by poor data quality.

The specificity is even higher (upper 90s) when the chief complaint is chest discomfort and the heart rate is < 100.

I certainly agree that the GE-Marquette 12SL algorithm sucks at cardiac rhythm interpretation.

Tom

Tom B said...
AD is right on the money as far as the GE-Marquette 12SL interpretive algorithm.

It's not particularly sensitive when it comes to diagnosing acute STEMI but it is fairly specific (but far from perfect).

I stand corrected


Why? Because the ACC/AHA STEMI criteria is far from perfect! Not to mention the algorithm is highly susceptible to being led astray by poor data quality.
Right, it may not catch every AMI, but it catches much of the STEMI Alerts based on AHA criteria, correct?

The specificity is even higher (upper 90s) when the chief complaint is chest discomfort and the heart rate is < 100.

I certainly agree that the GE-Marquette 12SL algorithm sucks at cardiac rhythm interpretation.

Tom

I agree.

Thanks for this. The STEMI interpretation algorithms have come a long way. W

Anonymous PE is S1 Q3 and T3

"Ex-medic" here again.

Yes, there is no S1Q3T3, but despite the traditional teaching, that sign has been shown to be rather poor at correlating with PE. T-wave inversions across the precordium have actually shown a much greater utility in suggesting or supporting a diagnosis of pulmonary embolism. Other support would come from an incomplete or complete RBBB, RAD, This summary sheet lists some of the evidence:
http://medicine.ucsf.edu/education/resed/Chiefs_cover_sheets/EKGinPE.pdf

Great EKG, and great discussion! Will there be a cath report to bring closure to this, or will we be left hanging?

Sorry! Try this
http://medicine.ucsf.edu/education/resed/Chiefs_cover_sheets/EKGinPE.pdf

Heck, having trouble pasting in the right url. Just google PE, Ecg, and either Mattu or Ferrari.
Sorry about the malfunctioning links!

Ex-Medic,

I believe tachycardia is the most common PE finding.

I do not have the angio. I do know the results of the cath though. Severe occlusion of the RCA.