ORAL PROPAFENONE TO CONVERT RECENT-ONSET ATRIAL-FIBRILLATION IN PATIENTS WITH AND WITHOUT UNDERLYING HEART-DISEASE - A RANDOMIZED, CONTROLLED TRIAL

Background: The effectiveness of oral propafenone in converting recent -onset atrial fibrillation to sinus rhythm has been established by con trolled trials. However, it is not clear whether the effectiveness of propafenone is affected by the presence or absence of underlying heart disease. Objectives: To investigate the safety and effectiveness of o ral propafenone and the role of underlying heart disease. Design: Rand omized, single-blind, controlled study. Setting: 3 teaching hospitals. Patients: 240 hospitalized patients with recent-onset atrial fibrilla tion. Intervention: Propafenone (one 600-mg oral dose) or placebo. Mea surements: Conversion rates at 3 and 8 hours. Results: Propafenone was more effective than placebo for converting atrial fibrillation to sin us rhythm at 3 hours: Fifty-four of 119 patients (45%) receiving propa fenone and 22 of 121 patients (18%) receiving placebo had conversion ( P < 0.001). It was also more effective at 8 hours: Ninety-one of 119 p atients (76%) receiving propafenone and 45 of 121 patients (37%) recei ving placebo had con version (P < 0.001). Subgroup analysis showed tha t among patients without heart disease, 78% of those receiving propafe none and 56% of those receiving placebo converted to sinus rhythm with in 8 hours (P = 0.02). In those with hypertension, the rate was 70% fo r those receiving propafenone and 27% for those receiving placebo (P < 0.001); in patients with structural heart disease, the rate was 81% f or those receiving propafenone and 17% for those receiving placebo (P < 0.001). Conclusions: Oral loading of propafenone was more effective than placebo for conversion to sinus rhythm with in 8 hours and had a favorable safety profile. The rate of spontaneous conversion to sinus rhythm was higher in patients without structural heart disease; this f inding has important implications for the assessment of drug effective ness in recent-onset atrial fibrillation.