What electrocardiographic change is indicative of hypokalemia?

The presence of prominent U waves on an electrocardiogram is indeed indicative of hypokalemia. In the context of electrolyte disturbances, hypokalemia refers to low levels of potassium in the blood, which can significantly affect cardiac electrical activity.

When potassium levels drop, it influences the repolarization phase of the cardiac action potential, leading to the appearance of U waves. These U waves are seen after the T wave and can become more pronounced or prominent in hypokalemic patients. This change provides a crucial diagnostic clue for clinicians assessing patients with potential electrolyte imbalances.

Other changes associated with different cardiac conditions do not typically correlate with hypokalemia. For instance, peaked T waves are more commonly associated with hyperkalemia, while decreased QRS amplitude and changes in PR interval can indicate different cardiac or conduction abnormalities not specifically tied to low potassium levels. Therefore, the prominence of U waves serves as a clear and specific indicator of hypokalemia in ECG readings.