[First experience of clinical use of new class III antiarrhythmic agent niferidil in patients with persistent atrial fibrillation and flutter].

The aim of the study was to evaluate the efficacy and safety of administered intravenously niferidil in doses 10, 20 and 30 mkg per kg in patients with persistent atrial fibrillation (AF) and flutter (AFL) for pharmacological cardioversion. The study included 30 patients (22 male) with persistent AF (n = 28) and AFL (n = 2) without structural heart diseases with median arrhythmia duration 6.1 +/- 4.8 months (2 weeks to 24 months). Niferidil was administered as 3 bolus injections (10 mkg per kg each) performed with the interval of 15 minutes. Antiarrhythmic efficacy of niferidil in dose of 10 mkg per kg was 60%, in dose of 20 mkg per kg it was 70%, and in dose of 30 mkg per kg reached 90% prespectively. The part of the patients, in whom QTc prolongation exceeded potentionally dangerous value of 500 mc, was 22.2% (6 of 27). None of the patients developed proarrhythmic side effect as torsade de pointes.

[The efficacy and safety of nibentan for pharmacological cardioversion in patients with persistent atrial fibrillation and flutter: the role of dose limitation and magnesium sulfate administration].

The aim of the study was to evaluate the influence of magnesium sulfate on the efficacy and safety of pharmacological cardioversion with nibentan (NB) in doses up to 0,125 mg/kg in patients with persistent atrial fibrillation (AF) and flutter (AFL). Calculated dose of NB was 0.125 mg/kg. It was administered as 2 bolus injections (0.0625 mg/kg each) performed with the interval of 15 minutes. The study included 64 patients (pts) (45 male, age 54+/-9,9 years) with persistent AF (n=56) and AFL (n=8) with median arrhythmia duration 6,7+/-6,8 months (8 days to 36 months). Pts were divided into two groups. In the first (I) group NB was used without preliminary magnesium sulfate administration, in the second group (II) magnesium sulfate was injected in a dose of 50 mg/kg, followed by 0.83 mg/kg/min infusion before NB administration. There was no difference between groups in conversion rates of atrial arrhythmias: 74% and 69%, in groups I and II, respectively (p>0.4). Mean effective dose of NB was the same in investigated groups - 0.09 mg/kg. Administration of initial dose of NB (0.0625 mg/kg) converted AF/AFL to sinus rhythm within 15-min interval in 29.7% of patients. Efficacy of full dose of NB (0.125 mg/kg) was 100% in AFL, 68% in AF. No side effects were registered after initial injection of 0.0625 mg/kg. After administration of 2 boluses (0.125 mg/kg) "torsade de pointes" developed in 2 pts (3%). Magnesium sulfate administration had no influence on NB efficacy and rate of its proarrhythmic events. Limitation of NB total dose to