Prenalterol in cardiogenic shock following acute myocardial infarction

Eleven patients with cardiogenic shock following acute myocardial infarction (AMI) have been treated with prenalterol. This drug was administered in seven patients once dobutamine or dopamine proved to be ineffective or poorly effective, and it was the first inotropic drug employed in four patients. Therapeutic dose of intravenous infusion ranged from 2.2 to 18 micrograms/kg/min (mean dose: 7 micrograms/kg/min), and was maintained for 2 to 4 hours. Since two patients received the infusion on two different occasions, a total of 13 cases were considered for statistical analysis. Prenalterol produced an increase in cardiac index (p less than 0.01), mean aortic pressure (p less than 0.02), net work index (p less than 0.01), net/stroke work index (p less than 0.01), pressure rate product (p less than 0.05), and myocardial perfusion gradient (p less than 0.02). It decreased systemic (p less than 0.02) and pulmonary (p less than 0.01) vascular resistances, pulmonary artery (p less than 0.01) and pulmonary capillary (p less than 0.05) pressures. Heart rate and right atrial pressure were not significantly changed. The drug acted as a relatively selective inotropic agent without a chronotropic effect and with minimal peripheral actions. It was effective in seven patients and ineffective in four patients. Thus prenalterol appears to be a useful drug in cardiogenic shock and further studies are warranted.