Niferidile is a novel potassium channel blocker that inhibits transient outward and delayed rectifier currents. According to preclinical studies, it increases effective refractory periods (ERP) more in atria, less in ventricles. High affinity of Niferidile to atrial myocardium predispose to high efficacy in patients with supraventricular arrhythmias and to low risk of ventricular arrhythmogenic action.Objectives
To evaluate electrophysiologic effects of Niferidile in patients without organic heart disease.Materials and methods
Effects of Niferidile (20micrograms/kg intravenously) on sinus node function, atrioventricular conduction and refractoriness of both atria and right ventricle were studied in 24 patients (15 males) with no evidence of organic heart disease in routine electrophysiological study. All patients were informed about the study and signed the consent form.Results
Niferidile did not alter sinus node recovery time and atrioventricular conduction. Niferidile increased the ERP of right atrium (by 23,11%; p < 0.001), left atrium (by 22.12%; p < 0.001), and right ventricle (by 14.02%; p < 0.05). Niferidile prolonged QT (by 22.4%; p < 0.01) and QTc (by 16.04%; p < 0.05) intervals without the evidence of proarrhythmic effect.Conclusions
Prolongation of ERP in cardiac tissues (mostly in atrials) is the main electrophysiologic effect of Niferidile in human heart. New drug demonstrated good safety profile without the evidence of proarrhythmic effect.