Abstract
The antiarrhythmic and general cardiovascular effects and acute toxicity of N-propyl ajmaline (NPA) and ajmaline (AJM) were studied in the dog, rabbit and mouse. NPA was approximately three to seven times more potent than AJM. In addition, the antiarrhythmic mechanism was investigated electrophysiologically on the isolated guinea pig atria and on the isolated dog ventricular muscle, right bundle branch and Purkinje fibres. Both drugs caused a decrease in the spontaneous beating rate of the atria, a prolongation of the refractory period and a reduction in the conduction velocity in the Purkinje fibres. The results of the study suggest that the actions of both drugs do not substantially differ, although they have quantitative differences.
