What immediate effect can high potassium levels have on the heart?

High potassium levels, or hyperkalemia, can significantly affect cardiac function, particularly by inducing arrhythmias. Potassium is a crucial electrolyte that plays a key role in maintaining the electrical activity of the heart. An increase in extracellular potassium concentration alters the resting membrane potential of cardiac cells, which can lead to a disruption in the normal initiation and conduction of electrical impulses. This disruption can manifest as various types of arrhythmias, ranging from benign alterations in heart rhythm to life-threatening conditions like ventricular fibrillation.

In contrast to the other options, which do not accurately reflect the immediate consequences of high potassium levels, the occurrence of arrhythmias stands out as a direct result of the cardiac electrical disturbances caused by hyperkalemia. By changing the excitability of cardiac cells and affecting the conduction pathways, high potassium can lead to abnormal heart rhythms that can compromise the effectiveness of the heart's pumping action and overall circulatory stability. Therefore, understanding the relationship between potassium levels and cardiac electrical activity is essential in assessing the risks associated with hyperkalemia.