Frequency‐independent blockade of cardiac Na+channels by riluzole: comparison with established anticonvulsants and class I anti‐arrhythmics

Guinea-pig cardiac Purkinje fibres (in vitro), anaesthetized rats (aconitine-induced arrhythmias), anaesthetized dogs, and conscious dogs with polymorphic arrhythmias produced by left anterior descending coronary artery ligation 24 h earlier.

Riluzole (0.3-100 microM in vitro; 0.3-3.9 mg/kg i.v. in vivo)

Established anticonvulsants (lamotrigine, lifarizine, phenytoin, carbamazepine) and class I antiarrhythmics (lidocaine, flecainide, disopyramide)

Maximum rate of depolarization of the action potential (Vmax) in vitro, and antiarrhythmic effects in vivo (delay of aconitine-induced arrhythmias in rats, restoration of sinus rhythm in dogs)surrogate