Hypokalemia causes U waves in the ECG seen as a positive wave just after the T wave. Hyperkalemia causes peaked T waves initially, then an intraventricular conduction delay with a widened QRS ...

U wave that occurs just after the T wave and is usually of smaller amplitude than the T wave. Flattening of the T wave. ST depression on occasion, which can mimic ischemia.

ECG findings in hypokalemia may include flat T waves, T wave inversion, ST depression, U waves, and in more severe cases, heart block and/or atrial and ventricular dysrhythmias, including torsades ...