[The antiarrhythmic effect of metoprolol (author's transl)].

The antiarrhythmic effect of metoprolol after chronic treatment has been evaluated by 24 hour Holter monitoring in 16 patients with several premature ventricular beats and in 14 patients with chronic atrial fibrillation and compared with the effect of a placebo. Metoprolol induced a mean decrease of heart rate of 14.5% in the 16 patients and reduced the mean value/min of the ventricular premature beats of the 51.2%. In addition the use of metoprolol abolished the ventricular premature beats in 9 cases, while in two cases there was an increase of their frequency. In the 14 patients with chronic atrial fibrillation metoprolol was able to reverse to sinus rhythm three of the patients and in the remaining 11 decreased the ventricular heart rate of the 33%.