Propafenone for conversion of recent-onset atrial fibrillation. A controlled comparison between oral loading dose and intravenous administration.

STUDY OBJECTIVE To compare placebo vs two different regimens of propafenone administration--intravenous administration or short-term oral loading--in converting recent-onset atrial fibrillation to sinus rhythm. DESIGN Single-blind placebo-controlled study. PATIENTS Eighty-seven patients with atrial fibrillation of recent onset (< or = 7 days' duration) admitted to the hospital without signs of organic heart disease (n = 42) or with systemic hypertension without signs or symptoms of heart failure (n = 45). The patients were assigned randomly to treatment with intravenous propafenone (29 patients), oral propafenone (29 patients), or placebo (29 patients). INTERVENTIONS Administration of propafenone intravenously (2-mg/kg bolus followed by 0.0078 mg/kg/min) or as short-term oral loading (600 mg orally single dose). Patients were submitted to Holter monitoring and conversion to sinus rhythm was evaluated at 1, 3, and 8 h. RESULTS Conversion to sinus rhythm was obtained within 1 h in 28% with intravenous propafenone, in 3% with oral propafenone, and in 3% with placebo. At 3 h, the efficacy of intravenous propafenone (41%) and of oral propafenone (55%) were statistically superior to placebo (10% of conversions) and at 8 h either intravenous or oral propafenone were effective in almost two thirds of the patients with a statistical difference vs placebo, whose efficacy was 24%. No major side effects were observed. CONCLUSIONS Propafenone as an oral loading dose is an efficacious and fast way of treating atrial fibrillation of recent onset and due to its simplicity of administration and safety can be preferred to the intravenous route.