Wednesday, November 21, 2012

An Emergency Physician Texted Me This ECG, Asking for Help in Interpretation and for Advice in Management

I  was in a meeting and received a text message: "can you look at an ECG?"

I texted back to take a photo and send it.

The patient is a male over 40 years of age with central chest discomfort for several  hours.  Here is the ECG, as texted:

What is your diagnosis?





Answer

I called her back and this is what I said:



“This is a definite posterolateral MI, with an occluded artery, probably an OM, but it is not technically a STEMI because there is not 1 mm in 2 consecutive leads.  He needs to go to the cath lab ASAP.”





How did I know this?

Because there is BOTH: minimal STE in I and aVL with reciprocal ST depression in III, AND ST depression in V2 and V3. 

Combine this with sudden onset of substernal chest pain and you have  a certain posterolateral MI.

She called the cardiologist on call and emphasized the need to go ASAP to the cath lab.  The patient's pain resolved completely with intensive medical therapy, and so the urgency was less.  Within a very short time, the patient underwent an angiogram that showed a 99% OM-1 occlusion and and 85% RCA.  Both appeared "hazy"; both appeared to be culprits and both underwent stenting.

A subsequent echo was normal, without wall motion abnormality.  Remember this! 

The troponin I peaked at 58 ng/ml, so this was not a small MI.



Learning points:

  • 25-30% of "NonSTEMIs" have an occluded infarct-related artery at 24 hours after presentation.  (1, 2, 3)
  • Many more are occluded at the time of presentation.
  • This ECG would be read as "non-diagnostic" by the vast majority of interpreters.  There are many "nondiagnostic" ECGs that really are diagnostic if scrutinized closely.
  • Cardiac ultrasound done after resolution of ischemia is only moderately sensitive for MI.




References

1.  Wang T, Zhang M, Fu Y, et al. Incidence, distribution, and prognostic impact of occluded culprit arteries among patients with non–ST-elevation acute coronary syndromes undergoing diagnostic angiography Am Heart J 2009;157(4):716-23.
2. From AM, Best PJM, Lennon RJ, Rihal CS, Prasad A. Acute Myocardial Infarction Due to Left Circumflex Artery Occlusion and Significance of ST-Segment Elevation. Amercan Journal of Cardiology 2010;106(8):1081-5.
3.  Pride YB, et al.  Angiographic and clinical outcomes among patients with ACS presenting with isolated ST-Segmment Depression: A TRITON-TIMI 38 Substudy.  Journal of the American College of Cardiology: Cardiovascular Interventions 2010;3(8):806-11.


8 comments:

  1. I'm curious if the lack of significant R wave progression until the low lateral leads is also indicative of posterior involvement?

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  2. Why isn't this is an anterior MI based on the st segment elevation?

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  3. There is no anterior ST segment elevation(???)

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  4. Steve -

    Interesting coincidence - the AHRQ Web M&M just published and ED case regarding a missed MI. Their "ECG #1" was essentially that pictured here, with "minimal STE in I and aVL with reciprocal ST depression in III, AND ST depression in V2 and V3." Cath on visit # showed a "branch occlusion" of the LCx.

    Since it's an M&M, things didn't go as well as with your patient. Check out the case at http://www.webmm.ahrq.gov/case.aspx?caseID=288, if so inclined.

    Thanks for the cases - I try to review one before every shift!

    Brooks Walsh
    MillHillAveCommand.blogspot.com

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  5. I'm a family doc doing ER staffing. I want to be better at ekg interpretation. would you or any other cardiologist or resident you know be willing to talk through with me ekg's I get in the ER ?

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    Replies
    1. You can send me ones you're wondering about at:
      dr.smiths.ecg.blog@gmail.com

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