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.