What electrolyte imbalance is characterized by T-wave flattening and U waves on an ECG?

The presence of T-wave flattening and U waves on an ECG is primarily associated with hypokalemia. In situations of low potassium levels, the heart's repolarization process is disrupted. Typically, hypokalemia leads to changes in the ECG morphology where T waves become flattened and U waves become prominent. U waves are extra waves that appear after the T wave and are indicative of slower repolarization of the cardiac repolarization mechanism.

Potassium plays a crucial role in maintaining the normal electrical activity of the heart, and when levels drop, it can lead to various cardiac arrhythmias. The manifestation of U waves along with T-wave flattening serves as a key diagnostic feature for identifying hypokalemia on an ECG.

This understanding of the ECG manifestations of electrolyte disturbances is vital for clinical practice, as recognizing these patterns can guide appropriate management of the patient's underlying electrolyte imbalance and reduce the risk of cardiac complications.