What characteristic EKG change is associated with hyperkalemia?

Tall, peaked T waves are a classic EKG finding associated with hyperkalemia. As potassium levels in the bloodstream rise, the effect on cardiac myocytes becomes evident. Increased extracellular potassium concentration alters the resting membrane potential, leading to changes in repolarization.

Initially, one of the earliest signs on an EKG in hyperkalemia is the presence of tall, peaked T waves, often described as a "tent" shape. This change is due to the accelerated repolarization of the myocardial cells, which reflects the increased potassium levels affecting the movement of potassium ions across the cell membrane during phase 3 of the cardiac action potential.

Further progression of hyperkalemia can lead to more significant changes in the EKG, such as widening of the QRS complex and potential development of a sine-wave pattern, but those are typically seen in more severe cases. Recognizing the tall, peaked T waves is vital for early identification and management of hyperkalemia, as it can quickly become a life-threatening condition if not addressed.

The other options represent different EKG changes that may arise from other conditions or more severe electrolyte imbalances but are not characteristic of hyperkalemia itself.