Hemodynamic and metabolic effects of dopamine and insulin during acute left ventricular failure in dogs

Acute ischemic heart failure was induced in eight dogs by coronary embolization. Severe depression of the left ventricular (LV) performance was evidenced. At 15 min after the embolization procedure, dopamine was infused at a dosage sufficient to increase the maximum rate of LV pressure rise (LVdP/dtmax) by approximately 50%. The significant improvement in cardiac performance was obtained at unaltered myocardial oxygen consumption (MVo2). Dopamine infusion was concluded, and after a stabilization period 300 IU of insulin was injected. This was followed by the infusion of glucose and potassium to maintain levels. Insulin significantly improved the performance of the failing left ventricle at unaltered MVo2, but to a lesser extent than did dopamine. Additional dopamine infusion further significantly improved cardiac performance. The net effect of insulin and dopamine in combination as compared with dopamine alone was a significantly greater increase in stroke volume and cardiac output due to a more pronounced decrease in total peripheral resistance. Dopamine increased arterial concentrations and myocardial uptake of free fatty acids (FFA). The net metabolic effect of insulin and dopamine in combination as compared with dopamine alone was a shift in myocardial substrate uptake from FFA to carbohydrates.