[Comparison of lidoflazine and quinidine in the conversion to sinusal rhythm in atrial fibrillation of recent onset]

In order to compare the efficacy of oral lidoflazine (240 mg/die) and oral quinidine (1200 mg/die) in re-establishing sinus rhythm, we studied 115 patients (mean age 63.8 years; range 32-91) with atrial fibrillation of recent onset (less than 3 months). Patients with cardiac failure, acute myocardial infarction, severe intraventricular conduction disturbances, kaliemia less than 3.8 mEq/L or digoxinemia greater than 2 ng/ml were not included. Patients were randomly given one of the 2 drugs, until conversion to sinus rhythm was achieved, severe side effects occurred or for a maximum therapy of 5 days. No significant differences were present between the 2 groups in terms of age, male/female ratio, duration of atrial fibrillation, presence of an enlarged left atrium, presence of organic heart disease (or arterial hypertension) or digitalis therapy. Sinus rhythm resumption was obtained in 41/58 (71%) patients treated with quinidine and in 47/57 (82%) patients treated with lidoflazine (p = ns). In successful cases, the mean treatment time was 79 +/- 33 (SD) hours for quinidine and 66 +/- 36 hours for lidoflazine (p = ns). Both drugs showed the same efficacy in 3 subgroups of patients in whom the arrhythmia had different duration (less than 24 hours; between 24 hours and 3 days; more than 3 days). Treatment was stopped in 5 patients receiving quinidine (gastrointestinal side effects) and in 3 patients receiving lidoflazine (frequent premature ventricular beats in 2 and polymorphic ventricular tachycardia of the "torsade de pointes" type in 1).(ABSTRACT TRUNCATED AT 250 WORDS)