The efficacy and safety of propafenone as an oral loading dose (600-mg single oral dose) in converting recent-onset atrial fibrillation (< or = 7 days duration) to sinus rhythm were evaluated in a single-blind, placebo-controlled study according to patients' age. Overall, 240 hospitalized patients, NYHA Class < or = 2 without signs or symptoms of heart failure were enrolled: among patients aged < or = 60 years, 55 were allocated to propafenone treatment and 59 to placebo, respectively, and among patients aged > 60 years, 64 were allocated to propafenone treatment and 62 to placebo, respectively.
Results: In each age group, the likelihood of conversion to sinus rhythm was significantly greater after propafenone compared with placebo at 3 and 8 hours. For patients aged < or = 60 years, corresponding odd ratios were 3.78 (95% CI = 1.80-7.92, P = 0.04) at 3 hours and 4.74 (95% CI = 2.12-10.54, P = 0.02) at 8 hours; for patients aged > 60 years odd ratios were 5.03 (95% CI = 2.08-12.12, P = 0.02) at 3 hours and 6.75 (95% CI = 3.28-73.86, P = 0.01) at 8 hours, respectively. Logistic regression analysis showed that conversion to sinus rhythm within 3 hours was predicted by age < or = 60 years (P = 0.0064) and by propafenone treatment (P < 0.0001), and conversion to sinus rhythm within 8 hours was predicted by age < or = 60 years (P = 0.0467) and by propafenone treatment (P < 0.0001). The occurrence of adverse effects was observed in 14%-16% of propafenone treated patients and in 8% of placebo treated patients without significant differences according to age. In conclusion, in patients with recent-onset atrial fibrillation without signs of heart failure, propafenone as a single oral loading dose is effective. It is also effective in selected elderly subjects with a favorable safety profile. Moreover, spontaneous conversion to sinus rhythm appears to occur less frequently in elderly patients.