Preservation of left ventricular function by insulin in experimental catecholamine cardiomyopathy

We have shown previously that insulin reduces myocardial injury associated with norepinephrine (NE) infusion in the rabbit (Am. J. Pathol. 93:399--353, 1978). In the present study, left ventricular function (LVF) was assessed from afterload curves obtained by progressive aortic constriction 2--4 days following NE infusion. The initial slope of the function curves (SFC), maximum dP/dt and left ventricular end-diastolic pressure at 120 mmHg ((LVEDP120) were used for comparison. In 4 controls, SFC averaged 23.8 mmHg/cmH2O. In 10 rabbits given NE, the mean slope was 8.4 (P less than 0.01). However, animals pretreated with insulin before being given NE did not differ from controls (SFC, 19.7 mmHg/cmH2O). These performance data were supported by measurements of LVEDP120, which were 2.8, 12.3 and 3.1 cmH2O, respectively (P less than 0.05 and less than 0.02). In spite of the higher LVEDP, max dP/dt120 was significantly lower in the NE group than in the group given insulin. Histological findings and postmortem measurements of LV volume and mass were consistent with the observed differences in LVF. It is concluded that NE damage reduces LVF and this is largely prevented by pretreatment with insulin.