[Novel class III antiarrhythmic agent niferidile: review of experimental and clinical studies].

This article reviews experimental and clinical studies of a novel antiarrhythmic agent niferidile. Niferidile, a class III antiarrhythmic agent, blocks potassium outward currents, prolongs repolarization and refractory periods predominantly in atria than in ventricles. Intravenous Niferidile was efficient for interruption of AV-nodal and orthodromic re-entrant tachycardias with rates of 75% to 80%. Niferidile had a conversion rate of up to 87.3% in persistent atrial fibrillation and up to 100% in persistent atrial flutter. Proarrhythmic action of niferidil administration manifested as nonsustained torsade de pointes and monomorphic ventricular tachycardia in 1.2 and 3.7% of cases, respectively. Niferidile can be used for pharmacological cardioversion of persistent atrial fibrillation and flutter as an alternative to electrical cardioversion.

[Cardiac resynchronization therapy in patients with permanent atrial fibrillation].

UNLABELLED: In our study we compared effect of cardiac resynchronization therapy (CRT) in chronic heart failure (CHF) patients with permanent atrial fibrillation (AF) and patients with sinus rhythm. Special feature of our work was that patients with permanent atrial fibrillation didnt have obligatory ablation of atrio-ventricular node but underwent aggressive rate control to achieve more than 90% of biventricular (BV) complexes. We used 24 hours Holter monitoring because there are data that this method is more accurate than CRT counters. METHODS: We included 30 patients: 21 patients with sinus rhythm and 9 patients with permanent AF with ejection fraction <35%, II-IV NYHA class and wide QRS (>120 ms). We examined patients before implantation of CRT and after 6 months. RESULTS: mean NYHA class decreased from III to II. Distance at 6-min walk test increased by 107 m in AF group and by 105 in sinus rhythm group. EF increased by 7% in AF group and by 6% in sinus rhythm group. Mean time of further observation was 2 years (from 10 months to 5 years). There was 1 death (11.1%) in AF group and 3 deaths (15%) in sinus rhythm group (p>0,05). CONCLUSION: CRT is effective in CHF patients with permanent AF and pharmacological rate control if percent of BV pacing is more than 90% on Holter monitoring.

[Electrophysiological effects and antiarrhythmic activity of novel domestic class III antiarrhythmogenic drug niferidil administered in patients with paroxismal supraventricular tachycardia].

Intracardiac electrophysiological effects and antiarrhythmic activity of novel domestic class III antiarrhythmogenic drug niferidil has been studied in a group of 25 patients with paroxismal supraventricular tachycardia (PSVT) diagnosis. The drug was administered in a dose of 20 mg/kg (i.v.). Niferidil injections increased the refractory periods in both right and left atrium (by 22 and 20%, respectively, p < 0.001), right ventricle (12%, p < 0.01), and the His-Purkinje system (34%, p < 0.001) and improved additional anterograde and retrograde conduction (by 22 and 31%, respectively, p < 0.001), while not influencing the conduction via excitable cardiac tissues. Elongation of the QTc interval (22%, p <0.05) in one case was accompanied by an arrythmogenic effect (induction of short-term polymorphous ventricular tachycardia of the "torsade de pointes" type. Niferidil arrested PSVT in 78% cases and prevented PSVT development in response to endocardial stimulation in 86% of patients.

[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.