ORAL LOADING WITH PROPAFENONE - A PLACEBO-CONTROLLED STUDY IN ELDERLYAND NONELDERLY PATIENTS WITH RECENT-ONSET ATRIAL-FIBRILLATION

The efficacy and safety of propafenone as an oral loading dose (600-mg single oral dose) in converting recent-onset atrial fibrillation (les s than or equal to 7 days duration) to sinus rhythm were evaluated in a single-blind, placebo-controlled study according to patients' age. O verall, 240 hospitalized patients, NYHA Class less than or equal to 2 without signs or symptoms of heart failure were enrolled: among patien ts aged less than or equal to 60 years, 55 were allocated to propafeno ne treatment and 59 to placebo, respectively, and among patients aged > 60 years, 64 were allocated to propafenone treatment and 62 to place bo, respectively. Results: In each age group, the likelihood of conver sion to sinus rhythm was significantly greater after propafenone compa red with placebo at 3 and 8 hours. For patients aged less than or equa l to 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 = 2.22-10.54, P = 0.02) at 8 ho urs; 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) a t 8 hours, respectively. Logistic regression analysis showed that conv ersion to sinus rhythm within 3 hours was predicted by age less than o r equal to 60 years IP = 0.0064) and by propafenone treatment IP ( 0.0 001), and conversion to sinus rhythm within 8 hours was predicted by a ge less than or equal to 60 years(P = 0.0467) and by propafenone treat ment (P ( 0.0001). The occurrence of adverse effects was observed in 1 4%-16% of propafenone treated patients and in 8% of placebo treated pa tients without significant differences according to age. In conclusion , in patients with recent-onset atrial fibrillation without signs of h eart failure, propafenone as a single oral loading dose is effective. It is also effective in selected elderly subjects with a favorable saf ety profile. Moreover, spontaneous conversion to sin us rhythm appears to occur less frequently in elderly patients.