Suricainide (also known as AHR 10718) is an aminoalkylurea derivative patented by A. H. Robins Co., Inc. as an antiarrhythmic agent. Suricainide induces a use-dependent decrease in Vmax and significantly decreased Purkinje fiber conduction velocity and action potential duration. Suricainide had no effect on slow response action potentials induced by isoproterenol but ventricular muscle action potentials were significantly prolonged by Suricainide. Suricainide significantly decreased normal automaticity, catecholamine-enhanced automaticity, and abnormal automaticity induced by barium or myocardial infarction. In preclinical modes, Suricainide suppresses the aconitine-induced canine atrial arrhythmia.