Friday, October 24, 2014

A Hybrid of de Winter's T-waves and Diffuse Subendocardial Ischemia: Left Main Ischemia

A very elderly woman who was highly functional complained of jaw pain and called 911.  Her BP was 80/40 with a puls of 45.  Here is her prehospital ECG:
There is ST elevation in aVR,  but also in aVL, V1 and V2.  There is diffuse, marked ST depression, in II, III, aVF, V3-V6.  The computer appropriately read ****Acute MI**** 


The ST elevation vector is superior and anterior, not to the right as one would expect with the typical "ST elevation in aVR MI", which would be reciprocal to diffuse ST depression (I, II, V3-V6).

This ST elevation vector is also not only towards aVL, as one would expect of the typical high lateral STEMI.  It also has a rightward/upward component toward aVR, and an antero-superior component toward V1 and V2.

The ST depression vector is also not typical of the "diffuse subendocardial ischemia" pattern which typically is towards leads II and V5, in the antero-lateral-inferior direction towards the apex of the heart.

[When there is diffuse subendocardial ischemia, the entire subendocardium is affected, causing ST depression vectors around the entire myocardium: inferior, lateral, posterior, anterior and apical (but not superior as this has little ventricular myocardium).  The additive effect of all this is an ST depression vector towards the apex.]

Thus the ST elevation vector is superior and anterior, and suggests STEMI of the very high part of the anterior and lateral wall and of the septum.  Does the remainder of the ST depression signify subendocardial ischemia or posterior STEMI?

This is all academic because such a high risk ECG and case requires immediate cath lab activation if such an elderly patient is in favor of aggressive therapy to save her life.  If you don't have a cath lab, then thrombolytics are also indicated, even by the rules (2 consecutive leads, V1 and V2, are involved).  The medics activated the cath lab before arrival in the ED.

The patient arrived in the ED talking and not in clinical shock, but with a low BP and low pulse.  There was no SOB or pulmonary edema.  This ECG was recorded:
Now there is no ST elevation in V2, but there is a hyperacute T-wave.  This is a de Winter's T-wave and diagnostic of near occlusion of the LAD.  V3 also has ST depression with a hyperacute T-wave very suggestive of de Winter's T-waves.  The ST depression persists.
The change from STE to de Winter's in V2 suggests some minimal flow in the artery.

The bedside cardiac ultrasound is shown here, in a slightly off-center parasternal short axis view:

This shows a dense anterior wall motion abnormality.  The posterior wall appears to be contracting effectively.

She was given atropine and this improved both her pulse and blood pressure.

Angiogram:

Black arrows are very narrowed left main, red arrow is LAD with flow, and yellow arrow is circumflex with flow.
Interpretation: 95% left main thrombus with TIMI-2 flow, with thrombus extending to the ostial LAD and the circumflex.

The patient was not a CABG candidate.   Angioplasty and stenting of this very high risk lesion (estimated mortality without therapy = 100%; estimated mortality with = 50%.  This is because, in order to treat a left main lesion, one must temporarily completely occlude it, which is very high risk).  Here is the ECG a couple days later:
Minimal signs of ischemia (mild ST depression)


Outcome:

Her heart did very well.  

However, the trouble with the very elderly is that they are frail, and all that antiplatelet and anticoagulant therapy can lead to other complications and she died.   In order to protect her identity, I cannot go into the details.




4 comments:

  1. Nice case - THANKS for presenting! I would not have guess left main stenosis ... I also love it when you show corresponding Echo & cath films - :)

    ReplyDelete
    Replies
    1. Thanks Dr Smith for another teachable moment. Where could I learn more about ST vectors. Not really grasping it yet. Thank you Eric

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    2. Try this post: http://hqmeded-ecg.blogspot.com/2012/02/five-primary-patterns-of-ischemic-st.html

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