Monday, March 4, 2013

Transient ST elevation and Peaked T-waves. Unstable Angina and Hyperkalemia.

Sinus rhythm.  ST elevation in I, aVL, V5, V6, with ST depression in V2-V4, diagnostic of posterolateral STEMI.  There are peaked T-waves in V2-V4

A woman in her 50's with multiple medical problems including DM and HTN and Mitral Valve replacement was at home when she began having shortness of breath, substernal chest pain, and diaphoresis for approximately 20 minutes, then called paramedics.

A prehospital ECG was recorded:


Nitroglycerine was given and the pain resolved, as did the ECG (not shown).  On arrival in the ED, she had this ECG recorded:
ST deviation is resolved, but peaked T-waves remain.  QRS duration is 94 ms
On further questioning, the patient then reported that earlier in the day, she was experiencing "cramps" in her chest and abdomen, and took "a bunch" of potassium supplementation (reasoning not certain here).  She was treated for hyperK and the K returned at 8.7 mEq/L.

She did not go to cath.  A workup 6 months previously had an echo with anterolateral and inferior wall motion abnormalities as well as an adenosine sestamibi with reversible inferior and lateral tracer uptake (positive) but at angiogram there had been no significant stenosis (though the degree of minor stenoses and soft plaques was not commmented upon).  The cardiologists had diagnosed her with coronary spasm.

She did undergo another echocardiogram at this visit, which was not different from the previous.

Troponins I (OCD Vitros):

Zero hour: undetectable
3 hours: undetectable
6 hours: 0.024 ng/ml (99% reference = 0.034)
10 hours: 0.018
14 hours: undetectable

These are consistent with unstable angina: a rise and fall with no value exceeding the 99% reference value.  ST elevation may be so brief that it does not result in positive troponins, but a rise and fall profile like this is diagnostic of ischemia in the appropriate setting.

Is she having coronary spasm, or are there nonobstructive coronary plaques that are unstable?  This remains uncertain.

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