Effects of Angiotensin II and Norepinephrine on Ventricular Performance During Oligemic Shock **

The administration of single large doses of angiotensin II has been shown to elicit positive chronotropic and inotropic effects in isolated heart preparations."' Continuous infusions of this hormone in normotensive animals, however, in amounts sufficient to produce marked vasoconstrictor responses, elicit only infrequent and transient increases of contractility.! Occasionally, negative inotropic transients associated with reduced coronary flow may occur.' The effects of angiotensin II upon ventricular function early and late in the course of oligemic hypotension has not been systematically examined. The data presented here indicate that animals in which ventricular function deteriorates after prolonged oligemic shock have large, sustained, positive inotropic responses to continuous infusions of angiotensin II.