I want some answers!!!
Well, we got ’em. Last week I posted an EKG quizzer. Funny looking 12-lead right? Prolonged QT? Dilaudid, Verapamil? Remember? No? Go check the link to refresh your memory: Friday 12-Lead.
Go ahead, I’ll wait.
OK, so we have signifcant QT prolongation. Or do we?
Is it me or does that T-Wave look kind of funny? Kinda’ looks a little flat-ish.
How about these two?
Hmm…I see a little bit of notching in the T-waves here. Almost like this isn’t just the T-wave we’re looking at. Maybe this will help a little bit: the patient’s potassium level when drawn was *drum roll please* 1.9mEq/L. Yes, 1.9mEq/L. She had gotten some replacement during the days, but obviously it was not enough.
What we have here is actually a QU segment as the U-wave from the hypokalemia has merged into the normal T-wave. More examples of this can be seen thanks to Google’s Book Search from Understanding Electrocardiography. It notes that you start to see dominant U-waves that merge with the T-wave when serum levels of potassium below 3.omEq/L, most notable in leads V2-V6 (as shown above), with the U-waves actually becoming larger than the T-waves when the levels drop to around 1.0mEq/L. Adverse events related to hypokalemia include AV blocks, torsades, V-Fib and cardiac arrest, which is not a surprise knowing how potassium works in the cardiac cycle. Typical causes of hypokalemia include diuretic use, alcohol abuse, loss through the GI tract from vomiting or suction (think NG tube) and some antibiotics just to give short list.
Electrolyte imbalances are also relatively common with pancreatitis, especially when you have vomiting. Our patient was pretty much past the vomiting stage having been NPO for 3 days. Combine that with having NS going at 250ml/hr for the last 2 days and we were flushing her K+ out of the system. Fluids were changed to add K and the rate was reduced. She got several K+ riders during day shift as well. Thankfully the on-call doc didn’t freak out and have us turn the dilaudid PCA off as that would have caused just a bit of a problem based on her usage. Even better was we never had to talk to the EP doc. Small things.
By the time I came back that night, her potassium was edging up to around 3.5 and her QT had normalized out to around 420ms. We get so tuned in to hyperkalemia that sometimes we forget that hypokalemia is just as significant. We were able to keep the potassium within normal for the rest of the stay and to no surprise, her QT intervals stayed normal and there was no recurrence of giant U-waves.
That’s your answer.