[Effects of digoxin on ventricular arrhythmia in patients with heart failure: relations with the state of the sympathetic-adrenal system].

Ventricular arrhythmias were analysed in 38 patients with Stages I-IIB heart failure from 24-hour Holter monitoring data obtained before and after digoxin therapy by comparing with the concentrations of catecholamines. There was a direct relationship between the plasma levels of epinephrine and norepinephrine and the severity of ventricular arrhythmias, as well as between the changes in cumulative catecholamine levels and ventricular arrhythmias during digoxin therapy. Virtually in all cases, the antiarrhythmic effect of the drug was accompanied by lower plasma catecholamine concentrations whereas the levels of norepinephrine and epinephrine remained nearly unchanged or increased with the tentatively arrhythmogenic action. The findings may suggest that hypercatecholaminemias are essential in the genesis of ventricular arrhythmias in heart failure. Cardiac glycosides can heterogeneously affect ventricular arrhythmias by modifying the activity of the sympathoadrenal system.