[Noninvasive evaluation of partial beta adrenergic agonist properties of xamoterol in cardiac insufficiency].

The effects of an intravenous injection of 0.15 mg/Kg of xamoterol were studied non-invasively under basal conditions and during beta-1-adrenergic stimulation with dobutamine in 16 patients with dilated cardiomyopathy and severe cardiac failure. Xamoterol did not cause any detectable agonist effect but was well tolerated under basal conditions. Its potential antagonist effect was only detected during the dobutamine infusion: xamoterol significantly reduced the increase in heart rate (p less than 0.001), the systolic blood pressure (p less than 0.01), the rate-pressure product (p less than 0.001) and the cardiac index (p less than 0.001) produced by the administration of dobutamine.