Abstract
By using dogs and cats, it was demonstrated that treatment with non-toxic doses of ouabain markedly enhanced the arrhythmic effects of catecholamines intravenously injected in the doses of 5 μg/kg. The production of ventricular arrhythmias by epinephrine or norepinephrine in digitalized animals was not prevented by a single injection of pronethalol or atropine, but it was prevented by combined administration of these too drugs. After stellate ganglia in both sides were removed, animals showed an increase in response to catecholamines which resulted in an induction of ventricular arrhythmias. The arrhythmias, in this case, was completely abolished by a previous administration of either pronethalol or atropine.
Thus, it was sugges ted that ouabaininduced enhancement of arrhythmic effects of catecholamines is connected with sympathetic, vagal and myocardial factors.
