What electrolyte causes U wave?

As a domain expert in cardiology, I can provide you with an informed response regarding the U wave on an electrocardiogram (ECG). The U wave is a positive deflection that occurs after the T wave in the cardiac cycle on an ECG. It is generally considered to be a normal variant, but it can become more prominent under certain conditions. The presence of a prominent U wave is often associated with conditions that affect the duration of the action potential of the ventricular myocardial cells. One of the key electrolytes that has been linked to the prominence of the U wave is Potassium. Specifically, Hypokalemia, which is a condition characterized by low serum potassium levels (typically less than 3.5 mEq/L), can lead to the appearance of a prominent U wave on the ECG. This is because low potassium levels prolong the repolarization of the ventricular myocardium, which can result in a more pronounced U wave. Additionally, it's important to note that while hypokalemia can cause a prominent U wave, critically low potassium levels (less than 1.7 mEq/L) can lead to a more serious condition known as torsades de pointes, which is a type of ventricular tachycardia associated with a high risk of sudden cardiac death. In summary, while the U wave is generally a normal variant, its prominence can be influenced by electrolyte imbalances, particularly hypokalemia.

The U-wave is a deflection following the T wave. Hypokalemia causes enlarged and prominent T waves on the EKG. Potassium levels that are critically low (<1.7) can lead to torsades de pointes.