A 70 y.o. woman who presented with L arm pain that started at 6:45 in the morning when she woke up. Pain was also in the upper back with some discomfort in the L chest. Described as "Achy" pain. She initially thought she must have slept wrong. No associated SOB, diaphoresis, or dizziness. No similar pain previously. No h/o CAD. She sat and rested but the pain got stronger, so she took 2 ASA. She felt a little "clammy." The pain went away after ~15 min. She lay down for ~20-25 min and while lying down the pain returned and persisted x 10 min prior to resolving again. She called 911.
She was pain free when the medics recorded 3 ECGs over 40 minutes. They all were similar to the first:
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V6 is missing. There are Q-waves in leads V3 and V4, with ST elevation and a large T-wave. Normally, one might think this ST elevation and T-wave is early repolarization, but early repol like this should 1) not occur in a 70 yo woman 2) never have Q-waves. Therefore, this is old MI with acute ischemia or acute STEMI.
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In the ED she was pain free. This was her ECG at presentation:
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QTc 442 ms. The T-waves in V3 and V4 are still large, but definitely smaller than in the prehospital ECGs. This is typical of hyperacute T-waves during reperfusion. You can compare the T-waves with her baseline (next ECG below). Additionally, there are new Q-waves in V2 and V3.
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look here for more on hyperacute T-waves:
http://hqmeded-ecg.blogspot.com/search/label/hyperacute%20T-waves
These ECG indicate that, at the time the patient was having pain, her LAD was occluded or nearly occluded. Old ECG from 3 years prior:
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QTc 405 ms. Normal previous ECG. No Q-waves. No ST elevation. No large T-waves.
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So the patient has a spontaneously reperfused LAD. Antiplatelet and antithrombotic therapy was begun.
At 113 minutes after presentation (first troponin was less than 0.04):
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QTc 447 ms. T-waves continue to diminish. Q-wave in V2, V3.
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Just before cath, time = 240 minutes:
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QTc 447 ms. T-waves very diminished now
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Here is a composite of V4-V6 from previous to prehospital to ED:
2 hours after LAD intervention (80% stenosis with hazy LAD thrombus):
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QTc 450. T-waves begin to invert. If this was the first ECG you had recorded in the ED, it would be Wellens' syndrome.
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Next Day. Troponin I peaked at 2.28 mcg/L.
The septum, anterior wall, and apex are akinetic on echo (myocardial stunning):
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T-waves evolve to become deeper and more symmetric
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3rd day, 48 hours.
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T-wave evolution continues |
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6th day, 120 hours:
Normal echocardiogram now:
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T-wave evolution continues |
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7 weeks later:
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R-waves present, T-wave inversion gone
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3 months later:
Summary:
1) With a large amount of myocardium at risk, there is a large wall motion abnormality
2) Hyperacute T-waves are a sign of a large amount of myocardium at risk
and that it is still viable
3) With minimal actual myocardial cell death (infarction), as shown by a low peak troponin, the myocardium will recover:
a) The myocardial function (as shown by echo) will recover (this may take weeks)
b) The ECG will recover (this may take months, as in this case).
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