Is maintenance digoxin necessary in patients with sinus rhythm?

Discontinuation of digoxin in 56 patients with sinus rhythm who had been taking it for a long time did not produce clinical deterioration in 33 of 34 patients whose pre-withdrawal steady-state plasma-digoxin concentration was less than 0.8 ng/ml; fast atrial fibrillation developed in the other patient. 22 patients had plasma-digoxin levels between 0.8 and 2.0 ng/ml before withdrawal--of these, 7 deteriorated without digoxin (5 had atrial fibrillation, which was associated with congestive heart-failure, measurement of the pre-injection period/left-ventricular ejection time (P.E.P./L.V.E.T.) ratio suggested that digoxin did exert a sustained positive inotropic effect. Thus, successful discontinuation of digoxin was possible in 86% of the total group and was more likely when the plasma-digoxin concentration was below 0.8 ng/ml. Unexpected atrial fibrillation was the commonest development inthe 8 patients in whom digoxin withdrawal was unsuccessful.