Investigation of Electrophysiologic Mechanisms for the Antiarrhythmic Actions of R 56865 in Cardiac Glycoside Toxicity

Normal anesthetized dogs, ouabain-pretreated dogs, normal isolated canine Purkinje fibers, canine ventricular muscle, and guinea pig papillary muscles

R 56865 (0.04 to 2.5 mg/kg i.v. in vivo; 0.1 to 10 microM in vitro)

Electrophysiological effects including conduction times, refractoriness, ventricular arrhythmias, Vmax, action potential duration, delayed after depolarization (DAD) amplitude, and triggered activitysurrogate