[Effect of allapinin on the function of the atrioventricular conduction system of the heart]

The effect of allapinin on atrioventricular conductivity was assessed at intracardiac electrophysiologic investigation in 11 patients with various heart rhythm disorders. The effect of a 30 mg intravenous dose of the drug was evaluated 60 min after the injection. Allapinin significantly lengthened the P-Q interval and expanded the QRS complex. The effect was associated with a 24% increment in the P-A interval, a 7% increment in the A-H interval and a 31% increment in the H-V interval, suggesting that allapinin can be regarded as belonging to the first class of antiarrhythmic agents by Vaughan Williams' classification. Allapinin also shortened effective refractory time of the atrium and the atrioventricular node, as well as the total refractory period of the His-Purkinje system. Ventricular refractory periods were also shortened insignificantly. The drug is therefore assumed to have a vagolytic or, perhaps, sympathomimetic action.