[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.