[Digitalis poisoning, risk factors and digitalis intolerance].

It was established by means of radioimmunoassay that the blood concentration of Digoxin in patients with congestive heart failure depends not only on the dose of the drug given, but also on the stage of cardiac insufficiency. With equal daily doses, higher Digoxin concentrations were observed in patients with more severe cardiac insufficiency. The analysis of the obtained data has demonstrated that in 75% of the patients with signs of digitalis intoxication the concentration of Digoxin in blood exceeded 2.5 ng/ml. In animal experiments it was established that a distinct reduction of the toxic threshold took place in rabbits with acute myocardial infarction, acute pulmonary embolism, congestive cardiac failure, this threshold being determined by the amount of intravenously injected Strophantin that causes persistent ventricular tachycardia.