Study Objective: To determine whether digoxin is effective in converting atrial fibrillation of recent onset to normal sinus rhythm.
Design: Randomized, double-blinded, placebo-controlled trial with a maximum 18-hour treatment period.
Setting: Emergency room and medical floors of a non-referral city hospital.
Patients: Consecutive sample of 36 patients with atrial fibrillation of 7 days' duration or less, not on digitalis glycoside or anti-arrhythmic agents, with ventricular rate between 85 to 175 beats/min, without evidence of heart failure, acute myocardial infarction, unstable angina, preexcitation syndrome, thyrotoxicosis, hypokalemia, renal impairment, or severe metabolic disturbances.
Interventions: Digoxin solution in capsules or identical placebo, given in doses of 0. 6, 0.4, 0.2, and 0.2 mg, at 0, 4, 8, and 14 hours, respectively, or until conversion to sinus rhythm, whichever occurred first. Continuous electrocardiographic recording by Holter monitor.
Measurements and Main Results: Nine of eighteen patients receiving digoxin and 8 of 18 receiving placebo had a return to sinus rhythm within 18 hours of study entry (95% confidence interval for the difference in proportions, -11% to 22%). Mean time to conversion was 5.1 hours in the digoxin group and 3.3 in the placebo group (95% Cl, -3.6 to 7.0 hours).
Conclusions: Spontaneous reversion to sinus rhythm is common in patients with atrial fibrillation of recent onset. Digitalization was not shown to affect the likelihood of reversion to sinus rhythm, and thus cannot be recommended for this purpose in patients with atrial fibrillation.