Abstract 17038: Novel Effective Class III Antiarrhythmic Agent Niferidile in Conversion of Persistent Atrial Fibrillation and Flutter
Niferidile (NF) is a new class III antiarrhythmic compound developed in Russia. It was shown to increase refractoriness in atria in much smaller concentrations than in ventricles. The aim of our study was to evaluate the efficacy and safety of i.v. niferidil in doses 10, 20 and 30 mkg/kg in patients with persistent atrial fibrillation (AF) and atrial flutter (AFL) for pharmacological cardioversion. We included 100 patients (64 male) in the study. 82 pts had AF and 18 had AFL. Arrhythmia duration was 4,2±3,9 months (from 2 weeks to 24 months). Mean left atrium size was 4,26±0,4 sm and LV ejection fraction was 59±4%. Niferidile was administered as 3 bolus injections (10 mkg/kg each) performed with the 15-min interval. If sinus rhythm was restored within 15 min after injection, the next injection was canceled. Drug efficacy was defined as sinus rhythm restoration during following 24 hours. Antiarrhythmic efficacy of niferidile in dose of 10 mkg/kg was 49%, in dose of 20 mkg/ kg it was 65%, and in dose of 30 mkg/ kg reached 88%. NF was effective in all 18 patients with AFL and in 70 of 82 patients (85%) with AF. In 1 patient after infusion of 10 µg/kg of NF QT interval prolongated up to 700 ms and unsustained runs of polymorphyc ventricular tachycardia of 3-9 complexes were registrated during 15 min. This patient converted to normal sinus rhythm in 22 hours after NF infusion. In one patient we noted symptomatic sinus bradycardia, developed in 5 min after sinus rhythm restoration, treated successfully by atropine injection. All patients demonstrated prolongation of mean QT after NF infusion in dose-dependent manner. It returned to normal value within 2 hours in patients, who received 10 mkg/kg of drug and within 22-23 h in patients, who received 20 or 30 mkg/kg of NF.
Summary: i.v. niferidile in doses up to 30 mkg/kg seems to be very effective for restoration of SR: 85% for persistent AF and 100% for persistent AFL, it seems to be sufficiently safe, proarrhythmic events are rare.
- © 2012 by American Heart Association, Inc.