Monday, December 29, 2014

All this teaching makes a difference! And a new paper on subtle ST Elevation.

One of my residency grads sent this.

A male in his 50's with h/o CAD presented with 2 days stuttering chest pain (also with nausea, diaphoresis, and SOB).  The chest pain had been constant for 2 hours.

"His first ECG was reviewed by a partner [who has not had as much training in ECGs) who said it was ok for the patient to wait in triage.  When he was roomed I took a look at his initial ECG."

Here it is:
This was his assessment:
"I saw the T-wave in inferior leads and immediately 'freaked out.'  Then I saw the subtle but non diagnostic ST elevation, but mostly it was the look of aVL which I've heard you talk about a million times now as being specific for inferior ischemia."


He got a repeat right away (24 minutes after the first):
"This showed STEMI, so I activated the cath lab."


Outcome:

The patient had severe diffuse CAD with a 99% thrombotic stenosis culprit in the circumflex, with TIMI-1 (very slow inadequate) flow.  It was stented.

Peak troponin was 53.5 ng/mL.

He is scheduled for CABG in 2 weeks.


What is the outcome of patients with MI who present with subtle ST elevation?  

Is it more benign than those with diagnostic ST Elevation?

This Spanish paper published this month in American Heart Journal by Marti et al. suggests that it is not more benign.

The authors have a very aggressive policy of taking patients to the cath lab immediately even for low suspicion of STEMI.  They studied 504 consecutive patients who were taken to the cath lab for suspicion of coronary occlusion.   86% were found to have TIMI 0 or 1 flow.  18% of these patients did not have any lead with at least 1 mm of ST elevation measured at the J-point.   These patients more frequently had multivessel disease and longer delays to reperfusion.  They had the same incidence of subsequent death or re-infarction.

Their study underestimates the number of subtle STEMI because they used 1 mm even in V2 and V3. The guideline recommended cutoff for these leads is 1.5 mm for women, 2.0 mm for men age greater than 40, and 2.5 mm for men aged less than 40.

Their conclusion was: "Subtle STEMI is frequent in clinical practice and is usually associated with acute total coronary occlusion.  Therefore, it should be diagnnosed and treated in the same expeditious manner as marked STEMI.  (Marti D et al.  Incidence, angiographic features, and outcomes of patient presenting withsubtle ST-elevation myocardial infarction.  Am Heart J 2014; 168:884-90.)

Learning point:

It is important to recognize subtle ST elevation myocardial infarction.  These patients are frequently not recognized and not taken for cath until the following day.  This study shows that patients with coronary occlusion frequently have minimal ST elevation.






7 comments:

  1. In such cases try to zoom in to 20 mm/mV and record again.

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  2. "99% thrombotic stenosis culprit": where ? (academic: RCA or LCX stenosis ?)

    thanks dr Smith for your beautiful cases (2008-2014): again .. again !

    Al

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    Replies
    1. Sorry! Circ. I will put that in. Thanks for catching the oversight!

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  3. In the initial ekg what is concerning in the inferior t waves? Is it that they appear hyper acute and about the same size as the qrs complex?
    In the follow up ekg, the stemi is approx 1mm in the iii and avf?

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    Replies
    1. Slight ST elevation, reciprocal ST depression in aVL, T-wave inversion in aVL, and T-waves that are too large in II, III, aVF. All together diagnostic of MI.

      Delete
  4. Hello Dr Smith

    Another great post - thank you for your continued teaching!

    I had a case today that I was sure was a subtle inferior STEMI however hospital staff disagreed and queried a musculo-skeletal issue. This male, 79, has a major cardiac hx, including previous stents, angina, AAA etc. BP was about 110 systolic, other vitals stable. Relief with nitrates.

    What do you make of this ECG? (Was I right to query RCA/Cx occlusion?)

    https://www.dropbox.com/s/sdsgbrvg6e7u8qy/STE%20Inferior.jpg?dl=0

    Thank you very much.
    Sam

    ReplyDelete
    Replies
    1. Sam, this one has a lot of voltage. LVH is one of the conditions that results in inferior ST elevation with reciprocal ST depression in aVL. Others are LBBB, WPW, and LV aneurysm (which will have a very well developed Q-wave in III - this one can be very hard to distinguish from acute MI).
      Steve

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