Exaggerated Ventricular Arrhythmias and Myocardial Fatty Changes After Large Doses of Norepinephrine and Epinephrine in Unanesthetized Dogs

Abstract

An intravenous infusion of a large dose (0.51 mg/kg) of norepinephrine sensitizes the heart to the action of catechol amines for a period of 2–4 days. During this period, small doses of either epinephrine or norepinephrine induce ventricular tachycardia. In dogs killed the day after infusion, frozen sections of the myocardium stained with Oil red O reveal fatty changes, the severity of which roughly parallels that of the induced tachycardias. Fatty changes were still present in the hearts of dogs killed the 3rd day after infusion, but were negligible 5 days after infusion. Similar, but less marked, cardiac effects were elicited by infusions of large doses of epinephrine.