Heart Force Effects of Sympathornimetic Amines as a Basis for Their Use in Shock Accompanying Myocardial Infarction

The treatment of 14 patients in severe shock accompanying myocardial infarction with i-norepinephrine (Levophed) in some cases and phenylephline (Neo-Synephrine) in others (lemonstratecl a significantly higher recovery rate with l-norepinephrine. Twelve of the patients were in congestive heart failure. Using strain-gage technics in fully conscious, trained dogs, l-norepinephrine was shown to produce substantial increments in heart contractile force in addition to its recognizedl plessor effects. Approximately equipressor (loses of Neo-Synephrine under the same conditions had little effect on contractile force. These pronounced differences in heart force effects