First results of the clinical use of ethacizin in patients with paroxysmal atrial fibrillation

: Fifty-six patients with frequently occurring paroxysms of atrial fibrillation were examined for the clinical efficacy of a new antiarrhythmic drug etacyzine (a diethylamine analog of etmozin). The use of the drug in doses of 50 to 70 mg intravenously and in doses in 150 to 200 mg per os a day removed and prevented the occurrence of atrial fibrillation paroxysms in 60 to 65% of cases, whereas etmozin in doses of 50 mg intravenously and 600 to 800 mg per os day did not produce any positive anti-arrthythma effect in the patients. The prolonged use of etacyzine (up to 1 year and over) exerted a beneficial antiarrhythmic action almost in all the patients. The drug did not provoke any serious side effects. However, in some patients, the use of the drug promoted a substantial prolongation of the P-Q interval and widening of the QRS complex of the ECG. In one female patient, the drug caused a paradoxical repetition of the ventricular rhythm.