Comparisons of oral propafenone and quinidine as an initial treatment option in patients with symptomatic paroxysmal atrial fibrillation: a double-blind, randomized trial

Objective. The main aim of the study was to evaluate the safety and efficacy of propafenone versus quinidine as an initial choice in treatment of symptomatic paroxysmal atrial fibrillation. Design. The study consisted of a 3-month treatment with oral propafenone hydrochloride or quinidine sulphate in patients with paroxysmal symptomatic atrial fibrillation, according to a double-blind randomized system. Setting. The study was performed in the out-patient clinic of university hospital. Main outcome measures. The effects of the two drugs on attack frequency, ventricular rate and symptoms of symptomatic paroxysmal atrial fibrillation. Results. In the oral propafenone group (n=48), two patients (4%) discontinued the treatment because of dizziness. In the 46 patients who continued the treatment, the attack frequency decreased from 11±3 times per week at baseline to 1±1 times per week after treatment (P<0.01). Forty (87%) out of the 46 patients had effective response to oral propafenone (more than 75% reduction of symptomatic arrhythmic attacks) on a mean dose of 615±10 mg day^-1; the decrease in attack frequency was from 10±3 to 1±1 times per week. Twenty-three (50%) patients were free from recurrence of symptomatic paroxysmal atrial fibrillation. Comparisons of symptom scores for patients (n=23) with attacks of paroxysmal atrial fibrillation after oral propafenone treatment showed that there was a significantly lower symptom score of palpitation, asthenia, effort dyspnea, dizziness, rest dyspnea and chest oppression in attacks of paroxysmal atrial fibrillation after propafenone treatment (11.05±3.78 versus 7.60±3.46, P<0.01). From the oral quinidine group (n=48), two patients (4%) discontinued treatment because of gastrointestinal discomfort. In the 46 patients who continued the treatment, the attack frequency decreased from 11±4 times per week at baseline to 3±2 times per week after treatment (P<0.01). Twenty-one (46%) out of the 46 patients had effective response to oral quinidine on a mean dose of 1067±462 mg day^-1, with a decrease in attack frequency from 12±3 to 1±1 times per week. Only 10 (22%) patients were free from recurrence of paroxysmal atrial fibrillation. Comparisons of symptom scores for patients (n=36) with attacks of paroxysmal atrial fibrillation after quinidine treatment showed that there was no significant decrease of symptom score in attacks of atrial fibrillation (10.65±3.92 versus 10.20±3.80, P=0.57). Furthermore, the percentage decrease of ventricular rate during atrial fibrillation was significantly greater in patients with propafenone (-25±4% versus -8±3%, P<0.01). Conclusions. Oral propafenone appeared to be more effective than quinidine in suppressing attacks and alleviating symptoms of paroxysmal atrial fibrillation.