Conversion of recent onset atrial fibrillation to sinus rhythm using a single oral loading dose of propafenone: comparison of two regimens

A population of 105 patients with recent onset (<72 h) atrial fibrillation was randomly treated with propafenone as a single oral loading dose of 450 mg (Regimen A) or 600 mg (Regimen B) or with placebo. A 24-h Holter was performed. Criteria of efficacy were conversion to sinus rhythm at 2, 4 and 8 h compared to placebo and also significant reduction of mean ventricular rate in persistent atrial fibrillation. After 2 h, regimen B was more effective than either regimen A (43% vs. 8%; p=0.001) or placebo (11%; p=0.004). At 4 h, both the active treatments were more effective than placebo (17% vs. 46% regimen A and 57% vs. regimen B; p<0.04 and p<0.001, respectively). Sinus rhythm resumed within 24 h in 71%, 80% and 69% of the patients with regimen A, B and placebo, respectively (p=not significant): The mean ventricular rate reduction after 1 h was 8%, 11% and 4% for regimen A, B and placebo, respectively (p<0.005 vs. regimen B), and 17%, 25% and 6% respectively (p<0.001 placebo vs. regimen A and B, p<0.05 regimen B vs. A) at 2 h. No major adverse effect occurred. Atrial flutter with 1:1 atrioventricular conduction ensued only in one case who received placebo. Propafenone acute oral administration is more effective than placebo in rapidly converting recent-onset atrial fibrillation to sinus rhythm and may be the treatment of choice in this setting limiting hospitalization and contributing to improved quality of life. Copyright (C) 1997 Elsevier Science Ireland Ltd.