Friday, November 29, 2013

What Does this ECG tell us about the Electrolytes?

See description and answer below

Hint: this is a dialysis patient

1. There are peaked T-waves
2. There is a long ST segment, resulting in a long QTc (490 ms).  See the ST segments in inferior and lateral leads especially.

Diagnosis: hyperkalemia (6.0 mEq/L) + hypocalcemia (causing long ST segment)  (ionized Ca = 3.41 mEq/L)

Here is the patient's ECG when the K = 4.1 and the Calcium is also low:
ST segments and QT are long (hypocalcemia), but the T-waves are not peaked.


  1. Dr. Smith, Would/did you treat this patient based upon the ECG with calcium?

    1. Only if there are symptoms of tetany. Renal failure patients may also have high phosphate and there is the unusual complication of diffuse calcinosis if too much calcium is given. Only if the PO4 x Ca product gets too high.

    2. Love your blog, but this is too much. (I have referred several med students to your blog). The ecg shows a previous anteroapical MI and minimal inferior ST elevation, not uncommon in my experience for people with previous mi. The ecg demonstrate inferior t waves which I would call "fat". Is there any evidence that a fat t wave represents acute injury? I might respond to the patient's chest pain and previous MI by calling in the cath lab but would not base this decision on the ECG. Help me understand what it is about this unusual repolariztion abnormality that should increase my suspicion for acute injury.

    3. Bruce, I think this comment was directed toward my post on 12/13/2013 about the male in his 60s with chest pain. I will write a whole new post to address your question.
      Steve Smith

  2. Dr. Smith, thanks again for your teaching - of immeasurable value.

    Can you clarify on the ionized value, Ca = 3.41 mEq/L - isn't that hypercalcemic? [iCalcium Range 2.32 - 2.64 mEq/L]

    1. Perhaps mine should be mmoles/L, not mEq/L. As Ca has a 2+ charge, that would make sense. Sorry.


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