[Treatment of acute myocardial infarction with metoprolol (author's transl)].

Metoprolol, a cardioselective beta-receptor blocker, was administered to 12 patients three to ten hours after sustaining a transmural myocardial infarction, and the effect of the drug (10 mg i.v., followed by 50 mg orally every eight hours) was followed for 48 hours. Heart rate decreased by 16% and cardiac output by 27%, while blood pressure and stroke volume decreased little and pulmonary "wedge" pressure was not significantly changed. Even in patients with initially definitely elevated left-ventricular filling pressure (greater than 20 mm Hg) the drug was well tolerated without any further rise in pressure. Since left-ventricular work was significantly decreased (stroke work--15%, cardiac output--31%) and the duration of diastole, decisive for coronary perfusion, was prolonged, it is concluded that early administration of beta-receptor blockers has a favourable effect on myocardial oxygenation and possibly reduce ultimate infarct size.