1. Elias Hanna, MD, Cardiology
Chest pain and dysphagia. ST depression in leads II, III, and aVF, and V3-V6. This ECG normalized few hours later, which suggests “dynamic ST depression” and thus ischemia. However, the pt’s history was not consistent with angina and her description was rather consistent with odynophagia. The pt actually had hypokalemia 2.8 on admission related to poor oral intake, and her ST depression is related to hypokalemia. Changes related to hypokalemia simulate ischemia and are dynamic (resolve with K therapy).
From Glancy DL. J La State Med Soc 2007; 159:5-7

2. Hypokalemia: ST depression with prominent T Flat T with K~3
(actually U) and prolonged QT
when K<2.5-3
Flat T with K~3

3. -T progressively flattens
Hypokalemia:
-T progressively flattens
-U wave more and more prominent (looks like T)
-ST-segment more and more depressed
Large U wave simulates and hides T wave with severe hypokalemia, the ST-T pattern
may mimick:
ST-segment depression with a flat or upright wide “T” wave (actually U)
and a prolonged “QT” interval (actually QTU)

4. On the other hand, the pattern of T inversion is not seen with hypokalemia:

5. ST depression ischemia ST elevation ischemia
Hanna EB, Glancy DL. CCJM June 2011 ST
depression
ischemia ST
elevation
ischemia