What could potentially occur if the rest potential is lowered due to excessive K+ levels?

Lowering the resting potential due to excessive potassium levels (hyperkalemia) can significantly affect cardiac function. The resting membrane potential of cardiac cells is primarily influenced by potassium ions, which are more concentrated inside the cell relative to the outside. When there is an increase in extracellular potassium, it reduces the concentration gradient for potassium across the cell membrane. This decrease can lead to a less negative resting membrane potential, making it easier for cells to reach threshold and trigger action potentials, but ultimately, it can disrupt the overall excitability of the cardiac tissue.

As the resting potential becomes less negative, this phenomenon can hinder the heart's ability to depolarize and repolarize properly. If the resting potential is too high, it can lead to cardiac cells becoming inexcitable, ultimately causing abnormalities in heart rhythm or complete failure to contract, known as cardiac arrest. This state poses a severe risk, as the heart may stop beating entirely, leading to a cessation of blood flow and oxygen delivery to vital organs.

In contrast, changes such as increased heart rate, reduced blood pressure, or enhanced cardiac output may not directly result from elevated potassium levels; in fact, these conditions can be compromised due to the adverse effects of hyperkalemia on cardiac rhythm and function. Thus