Membrane mechanisms of antiarrhythmic effect of quaternidine.

Complex electrophysiological study of the effects of quaternidine carried out on intact hearts from cats, myocardial fragments from rats, and single ionic channels of large edible snail showed that quaternidine demonstrates properties of class 1B antiarrhythmic drug according to Vaughan-Williams nomenclature. This agent did not suppress nomotopic pacemaker automaticity, did not change conduction in ventricles, atria, and atrioventricular junction in hearts with preserved sinus rhythm, did not prolong refractoriness of the atria and atrioventricular junction, but prolonged efficient refractory period of heart ventricles. Quaternidine decelerated rapid depolarization of the action potential, but had no effect on its duration. It did not affect potassium conductance.