Plasma levels of Digoxin in patients with atrial fibrillation and indications to the association with beta blockers

The influence of practolol on the activity of digoxin in atrial fibrillation has been studied in seven hospitalized patients by determining plasma levels of the cardiac glycoside and its effects on the ventricular rate, before and during the association with the beta blocker. Digoxin alone (0.25 mg/day p.o.) demonstrated a rather feeble activity, by giving a satisfactory control of ventricular rate only in two patients. Furthermore, a poor correlation has been observed between plasma levels and ventricular rate in the different patients. The association with low doses of practolol (50 or 100 mg twice a day p.o.) results in a significant increase of activity) tachycardic patients being the most responsive to the combined therapy.