Ryanodine-receptor inhibition by dantrolene effectively suppresses ventricular arrhythmias in an ex vivo model of long-QT syndrome.

Inhibition of the ryanodine receptor by dantrolene significantly reduced occurrence of polymorphic VT in drug-induced LQTS. A significant reduction of spatial dispersion of repolarization represents a major antiarrhythmic mechanism. These results imply that dantrolene may represent a promising antiarrhythmic option in drug-induced LQTS.