A 41-year-old male presents with a history of hypertension, diabetes mellitus type II and recent weight loss, nausea and dyspnea. He is receiving chronic hemodialysis and is found to be anemic with a hemoglobin of 9.8 g/dL (gram/ deciliter). An ECG is performed (Figure 1).
Figure 1:
Which of the following best explains this ECG?
Show Answer
The correct answer is: C. Hyperkalemia and hypocalcemia.
The T wave are narrow, which is the hallmark of hyperkalemia. The potassium level is 6.1 mmol/L (millimole/liter) with normal serum potassium level between 3.5-5.0 mmol/L.
The QT interval is mildly prolonged due to hypocalcemia. Measured QT interval is at 430 ms (milliseconds), which results in a corrected QT (QTc) interval at 474 ms. The normal QTc interval in adult male is < 450 ms. The calcium level is 8.1 mg/dL (milligram/deciliter) with normal serum calcium level between 8.6-10.5 mg/dL.
Hypocalcemia does have long QT, but this is secondary to lengthening of the ST segment. The QT prolongation here does not predispose to TdP.
The combination of hypocalcemia and hyperkalemia, often seen with left ventricular hypertrophy (LVH) (caused by hypertension) is the classic triad for chronic kidney disease. The ECG (Figure 1) may not meet criteria for LVH by conventional criteria.
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