The intravenous form of the Soviet anti-arrhythmic pharmaceutical ethacizine has been studied clinically. The pharmaceutical was administered to 30 patients with ventricular rhythm disorders during 3 to 15 minutes, at an average dose of 0.63 mg per 1 kg body weight, under the Holter monitor control. On the average the effect became apparent 6.5 min, after the injection and lasted on the average 149 +/- 15 min. Etacizine was effective in 77% of cases. It was established that there was no pronounced negative effect on the heart rate and the arterial pressure. Uzineg the tetrapolar rheography method it was shown that there was no pronounced negative effect on the central hemodynamics. The observation was made that etacizine induced a moderate decrease of the conductivity in atria AV-system and ventricles. Etacisin could be successfully used for rapid suppression of the ventricle rhythm disorders in various forms of coronary disease of the heart.