Which of the following is a common cardiac electrical change associated with hyperkalemia?

In hyperkalemia, elevated levels of potassium in the blood lead to distinctive changes in the cardiac electrical activity, particularly affecting the QRS complex. The correct identification of this change is the widening and flattening of the QRS complex. This occurs because increased extracellular potassium levels affect the resting membrane potential of cardiac myocytes, making it easier for them to reach the threshold for depolarization. As a result, the conduction velocity through the ventricles decreases, which is manifest as a broader and often more distorted QRS complex on the electrocardiogram (ECG).

This change is clinically significant as it can progress to more severe arrhythmias and underscores the importance of monitoring potassium levels in patients at risk for hyperkalemia.