What abnormality is associated with the presence of large U waves on an EKG?

The presence of large U waves on an EKG is primarily associated with decreased potassium levels, a condition known as hypokalemia. U waves are often seen following the T wave in the cardiac cycle, and their prominence can indicate an underlying electrolyte imbalance. When potassium levels drop, it can affect the repolarization phase of the cardiac muscle cells and contribute to changes in the EKG, including the formation of larger U waves.

Hypokalemia may also lead to other cardiac issues, such as arrhythmias, which can further impact the heart's electrical activity. This emphasizes the importance of recognizing U waves as a potential indicator of electrolyte disturbances, particularly in patients with symptoms suggestive of low potassium levels. Monitoring potassium levels is crucial in settings where patients are at risk of electrolyte imbalances, as it directly affects cardiac health and patient safety.