What typically occurs on the EKG when a patient has very low potassium levels?

When a patient has very low potassium levels, one of the characteristic changes observed on the EKG is the presence of a U wave. U waves are small deflections that occur after the T wave and represent the repolarization of the Purkinje fibers or the ventricles. In hypokalemia, the U wave becomes more prominent due to increased durability of cardiac repolarization, leading to significant alterations in the EKG.

Low potassium levels can also lead to various other EKG changes, such as flattening or inversion of the T wave or even the appearance of peaked P waves, but the presence of a U wave is specifically indicative of hypokalemia. It is an important clinical sign that healthcare professionals look for when evaluating a patient with suspected potassium deficiency. Monitoring these EKG changes is crucial because they help assess the severity of the hypokalemia and guide treatment decisions.