In the present investigation, the effects of different concentrations of digoxin (5x10^-8 -5 x 10^-6 M) on the number of premature ventricular contractions (PVCS), incidence, onset and duration of ventricular tachycardia (VT) and fibrillation (VF) have been studied on the isolated rat heart.
Digoxin (5 x 10^-8 - 5 x 10^-6 M) had no effect on the number of premature ventricular contractions, the incidence and the duration of ventricular tachycardia. Digoxin at the high concentration (5 x 10^-6 M) has significantly reduced the onset of reperfusion induced ventricular tachycardia. It also increased the incidence and duration of reperfusion induced ventricular fibrillation.
The present investigation suggests that administration of high doses of digoxin may modulate the severity of arrhythmias resulting from reperfusion of ischaemic myocardium. This effect may be mediated through the effect of digoxin on the distribution of potassium and calcium ions.