[Propafenone versus hydroquinidine in long-term pharmacological prophylaxis of atrial fibrillation]

New antiarrhythmic class 1C agents have been proposed in the last few years in an attempt to suppress paroxysmal atrial fibrillation at long-term, as the most commonly used class 1A agents such as quinidine gave highly variable results as regards both side-effects and efficacy. The aim of this randomized prospective study is to evaluate the efficacy and safety of oral propafenone at long term in preventing paroxysmal atrial fibrillation and to compare the results with those obtained using agents such as quinidine. Two hundred patients with recurrent episodes of symptomatic atrial fibrillation were enrolled for this study with entry criteria based upon a history of more than 3 crises in the previous 6 months, with electrocardiographic (standard electrocardiogram or dynamic registration) documentation. According to a randomized selection either propafenone at 300 mg twice daily or hydroquinidine retard 250 mg twice daily were administered to the patients; clinical check-up was carried out every 3 months or if clinical course worsened. The dosages were increased if proved to be inadequate at check-up (i.e. recurrence of atrial fibrillation) up to 300 mg 3 times daily for propafenone and 500 mg twice daily for hydroquinidine. The efficacy at the 3rd month was 71% for propafenone and 60% for hydroquinidine, at the 6th month 60% for propafenone and 56% for hydroquinidine; this trend lowered progressively as the follow-up continued, to 48% for propafenone and 42% for hydroquinidine (NS). More than 70% of the responder patients assumed 600 mg twice for propafenone or 250 twice for hydroquinidine. Propafenone had a percentage of 10% side-effects and hydroquinidine 24% (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)