Voltage-gated K⁺ channels (K_V) have a significant role in numerous cellular processes including regulation of apoptosis, cell growth and differentiation, and maintenance of cardiac activity. 

Cardiac K_V channels are also known as hERG channels and are involved in action potential (AP) propagation in cardiac myocytes. The AP is elicited by inward sodium current and rapid depolarization of the membrane. Repolarization is divided into several phases - an initial rapid and short depolarization is followed by a much slower “plateau” phase that ensures sufficient time for entry of extracellular Ca²⁺ into the myocyte for optimal excitation-contraction coupling. In addition, delayed repolarization also makes cardiac muscle refractory to premature excitation - an important safeguard against the generation of re-entrant arrhythmia. This phase is prolonged because the potassium influx through the hERG channel is slow to activate and is reduced at positive membrane potentials^1,2.