Adekalant (also known as H 345/52) is an innovative antiarrhythmic compound characterized by minimal proarrhythmic activity. It blocks HERG-mediated currents in a concentration-dependent manner, with a half-maximal inhibitory concentration (IC50) of 230 nM. Adekalant binds preferentially to open channels and exhibits rapid kinetic behavior, being trapped when channels close. Its voltage-independent properties have been observed during square pulse and action potential clamp protocols. Research suggests that delaying the repolarization of human cardiac muscle through I(Kr) blockage is the primary mechanism of Adekalant’s action. It effectively blocks I(Kr) while having relatively low efficacy in blocking I(Ca), delaying ventricular repolarization without significantly increasing temporal or spatial dispersion and without inducing early afterdepolarizations or torsades de pointes (TdP).