Tuesday, January 31, 2012

Chest pain in an 80 year old: What is the diagnosis?

An 80 year old male with h/o CABG presented with CP.  Here is his initial ECG (which was identical to his prehospital ECG) at 1517:


There is evidence old inferior MI.  What is the acute finding? Answer below.











This is another acute LAD occlusion.  There is slightly more than 1 mm of ST elevation in V2 and V3 at the J-point.  Is this normal or is it pathologic (STEMI or even LVH)?  First, it is clearly not LVH.  Second, normal variant ST elevation always has good R-wave progression.  If you add up the R-wave amplitudes in V2-V4 and it is less than 15 mm (here it is 11 mm), it is almost never early repolarization.  Finally, using the equation (see sidebar excel spreadsheet) and the computerized QTc of 399 ms, the value is 24.4 which is greater than 23.4 and heavily favors STEMI.

The resident saw this but the faculty was not convinced.  Chest pain continued and this repeat ECG was recorded at 1652:

There is slightly more ST elevation




A 3rd ECG was recorded at 1720:
There is still more ST elevation and the T-waves are larger.


At this point, the cath lab was activated.  Angiogram revealed an acutely occluded saphenous vein graft to the LAD which was opened with PCI.  Here is the post cath ECG:
Now there are T-wave inversion analogous to Wellens' syndrome.  These are reperfusion T-waves, also seen in I and aVL, indicating involvement of the lateral wall from a proximal LAD.


The next day ECG is here:
T-wave inversion is evolving as it normally does after reperfusion.

Troponin I peaked at 38 ng/ml.  Notice how important serial ECGs are if the initial ECG is nondiagnostic or not recognized.

8 comments:

  1. Dr. Smith...

    In addition to the slight increase in ST elevation between 1st and 3rd ECG, it also seems that the size of the T wave increased as well, most notable in V3 and V4 (by third ECG, T wave is now taller than R wave)...

    As to the evolution of post reperfusion T waves, i notice it as well in I and aVL, although aVL was inverted to begin with... how does that fit in, if at all?

    thanks,
    Dave B

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  2. I'll mention those things, thanks. see revisions above!

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  3. Tough case, especially with the minimal reciprocal changes in the lateral leads. Thanks for sharing.

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  4. in the first tracing posted, with a small amount of ST elevation in III and aVF and the ST depression in I and aVL, how does one determine whether the inferior MI is new or old? do the Q waves always favor old MI?

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  5. Tom,

    In general, it is very difficult to tell the difference between an acute inferior STEMI and an old MI with persistent ST elevation. The best way is the acuteness of the T-waves. However, in this case the STE is so minimal that I would heavily favor old MI. And the T-waves are also not acute.

    See these cases for a flavor of inferior T-waves that are acute:

    http://hqmeded-ecg.blogspot.com/search/label/inferior%20hyperacute%20T-waves

    Still it's a tough differential and I have not yet figured out a really good way to differentiate them.

    Steve

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  6. You guys are all correct, it's very difficult to pick up the slight ECG variants of a patient with an old infarction presenting with new symptoms especially after a CABG. I guess we can all learn from this case, that serial ECG are a must, and that post infarct/post bypass patients never completely fit the "textbook" pattern we often categorize ECGs into falling under. Always go clinical,always dig deeper, as that chest pain the patient was having had to arise from some coronary pathology old or new.

    Dan

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  7. I think there is a hint of Wellens Syndrome with slight biphasic T waves in V2-V4 suggesting obstruction to LAD. H/o CABG obscures the reliability. what do you think? Great ECG though!!

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  8. I think you're being tricked by a U-wave, which follows. Also, Wellens' only occurs with an open artery. It is a result of reperfusion.

    Nice observation, though.

    Steve Smith

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