[Prenalterol (CGP 7760 B), a new cardioselective beta 1-adrenoceptor-agonist (author's transl)]

The haemodynamic effects of the new selective beta 1-receptor-agonist prenalterol were investigated in two groups each of 8 patients. Dosages of 500 microgram/5 min and 100 microgram/1 min were given after direct closure of atrial septal defect under neuroleptanalgesia. Prenalterol 500 microgram/5 min increased cardiac index (37.5%), heart rate (19%), stroke index (16.2%), mean arterial pressure (26.5%) and dp/dtmax (84.5%) significantly. Total systemic resistance, total pulmonary vascular resistance and mean pulmonary pressure remained constant. Filling pressures of both ventricles decreased slightly but significantly. Maximal hemodynamic changes after infusion of 100 microgram/1 min prenalterol were half as great as with 500 microgram/5 min and occurred 3 min earlier. The haemodynamic action of prenalterol was rather long lasting. One hour after cessation of the drug-infusion there were still detectable haemodynamic effects. In contrast to investigations in awake patients there was a greater increase in heart rate, which is referred to influences on the vagal reflex caused by anaesthesia.