COMPARATIVE-STUDY OF THE EFFICACY AND SAF ETY OF 2 MODALITIES OF INTRAVENOUS CIBENZOLINE ADMINISTRATION IN THE REDUCTION OF RECENT-ONSET, SPONTANEOUS ATRIAL ARRHYTHMIAS

This multicentre, single blind, parallel group study compared the effi cacy and clinical and electrocardiographic tolerance of a 2 minute int ravenous administration of cibenzoline at a dose of 1.2 mg.kg(-1) with that of a 10 minute 1.75 mg.kg(-1) infusion in patients presenting wi th sponta neous atrial fibrillation (AF) for less than 6 weeks. Sixty- two patients (40 men and 22 women) with an average age of 62 years and presenting with sustained AF for at least 30 minutes with a ventricul ar rate greater than or equal to 80 bpm were randomly assigned to grou ps and received via the intravenous route either one of the two treatm ents. Efficacy (return to sinus rhythm) was assessed by an ECG recordi ng every 5 minutes and at 45 and 60 minutes thereafter. Sixty-one of t he 62 randomised patients were assessed for efficacy. Cibenzoline, adm inistered in the form of a bolus or infusion, proved effective within one hour in 4 patients in each group (13%) and arrhythmia persisted wi th ventricular rate of less than 80 bpm in 10 (33%) and 5 (16%) of the patients respectively. In patients in whom sinus rhythm was not resto red, ventricular rate was significantly reduced by cibenzoline. The pa tients in whom normal rhythm was restored under one of these treatment regimens were significantly younger. Patients in whom rhythm returned to normal following the administration of the bolus had AF of signifi cantly more recent onset than that of the patients in whom abnormal rh ythm persisted, whilst the history of the AF did not differ significan tly between these two types of response after the infusion. No signifi cant difference was observed between the patients in whom abnormal rhy thm resolved and the remaining patients with regard to left atrial dia meter and the ejection fraction of the left ventricle, regardless of t he mode of administration. The two treatments resulted in a significan t and comparable increase in the duration of the QRS and the QT. Three patients presented with unpleasant side effects which did not, howeve r, result in their withdrawal from the trial. One additional patient, following infusion, presented with transformation of atrial fibrillati on into atrial tachycardia with 1/1 conduction and broad QRS. This was poorly tolerated and required reduction by endocavitary stimulation p atients presented with ventricular pro-arrhythmic effect or cardiac fa ilure. Cibenzoline administered by a simple 2 minute intravenous injec tion of 1.2 mg.kg(-1) proved to be as effective and well tolerated as a 10 minute, 1.75 mg.kg(-1) intravenous infusion.