What condition can prominent U waves indicate?

Prominent U waves on an electrocardiogram (ECG) are typically associated with hypokalemia, which is a lower than normal level of potassium in the blood. The U wave represents repolarization of the Purkinje fibers and the ventricles. In the setting of hypokalemia, the changes in the cardiac muscle's electrical activity can lead to the development of prominent U waves, which may appear after the T wave.

In contrast, conditions such as hyperkalemia can lead to changes in the ECG primarily characterized by tall, peaked T waves, while acidosis and hypernatremia do not typically produce prominent U waves. Hypokalemia is the condition most closely linked with these distinct ECG changes, making it the correct answer in this scenario. Understanding the relationship between electrolyte imbalances and their corresponding ECG changes is crucial in surgical practice and the management of patients with cardiac concerns.