Metoprolol--a new cardioselective beta adrenoceptor antagonist in experimental cardiac arrhythmias
Sivam, S.P.; Seth, S.D.
Indian Journal of Medical Research 68: 176-182
1978
ISSN/ISBN: 0019-5340 PMID: 700845 Document Number: 132818
The antiarrhythmic effect of metoprolol was compared with propranolol on epinephrine-induced arrhythmias in cats, arrhythmias produced by coronary artery ligation in dogs and ouabain-induced arrhythmias in guinea-pigs. Anti-arrhythmic effects of metoprolol and propranolol were observed in all 3 types of arrhythmias. Metoprolol (2.5 mg/kg i.v.) and propranolol (0.5 mg/kg) protected the animals against epinephrine-induced cardiac arrhythmias. The incidence of ventricular arrhythmias in the conscious coronary-ligated dogs was significantly reduced by 5 mg/kg metoprolol and 3 mg/kg propranolol. Metoprolol and propranolol were also effectivein protecting guinea-pigs against ouabain-induced cardiotoxicity in the dose level of 15 mg/kg and 2 mg/kg respectively. Metoprolol controls adrenergically-induced arrhythmias by its .beta.-adrenoceptor blocking effect, but membrane activity may play a predominant role in the suppression of digitalis-induced arrhythmias and those resulting from coronary artery ligation.