Decreased levels of extracellular potassium ions causes the resting membrane potential to become . As a consequence, it takes for the membrane to depolarize to threshold.

hyperpolarized, longer.

Explanation:

An increase in potassium ions in the cardiac tissue will enable heart rate & volume to decrease.

The extracellular potassium concentration around a myocyte increases, and the potassium gradient accross the cell membrane reduces, and in turn the resting membrane potential will be more positive. There will be more negative resting membrane potential if extracellular potassium reduces.

Lesser potassium levels in the extracellular space will cause hyperpolarization of the resting membrane potential. For action potential to be initiated, depolarization of the membrane must be done essentially by a larger than normal stimulus.

Hypokalemia results in hyperpolarization in the myocytes' resting membrane potential in the heart. When there is more negative membrane potentials in the atrium it may result arrhythmias because of a more complete recovery from sodium-channel inactivation, less likely enabling the triggering of an action potential. Futhermore, the reduced extracellular potassium reduces the activity of the IKr potassium current and make ventricular repolarization slower. A delayed repolarization may project re-entering of arrhythmias.