An increase in which cardiac factor may indicate hypokalemia based on ECG readings?

An increase in U waves on an ECG can indicate hypokalemia. U waves are small deflections that appear after the T wave and are often associated with low potassium levels in the blood. When potassium levels drop, it can lead to changes in the heart's electrical activity, which manifests as prominent U waves on an ECG.

In the context of hypokalemia, elevated U waves can be a significant indicator. They often become more pronounced as the severity of potassium depletion increases. Therefore, monitoring U waves can help healthcare providers assess the potential impact of hypokalemia on cardiac function.

While changes in the QRS waveform, T waves, and PR interval can occur due to various cardiac and electrolyte issues, they are not specifically associated with hypokalemia as prominently as U waves are. This makes U waves a key diagnostic feature in the context of electrolyte imbalance, particularly concerning potassium levels.