Hypokalæmia: Large TU Waves

Report:

Sinus rhythm

Large TU waves consistent with hypokalæmia

Comment:

Normally, T waves become flat and the U waves increase in amplitude with hypokalæmia; occasionally, T waves remain upright and merge with U waves to produce striking TU waves like in this example. Sometimes this configuration is mistaken for hyperkalæmia143.

The very rounded TU contour in the inferior leads is almost pathognomonic of hypokalæmia. The level was 2.7 mEq/L.

The normalised trace is shown below (Fig 199a). It can be seen the patient normally has prominent T waves.

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