Improvement by denopamine (TA-064) of pentobarbital-induced cardiac failure in the dog heart-lung preparation.

The efficacy of denopamine, an orally active beta 1-adrenoceptor agonist, in improving cardiac failure was assessed in dog heart-lung preparations. Cardiac functions depressed by pentobarbital (118 +/- 28 mg; mean value +/- SD) such that cardiac output and maximum rate of rise of left ventricular pressure (LV dP/dt max) had been reduced by about 35% and 26% of the respective controls were improved by denopamine (10-300 micrograms) in a dose-dependent manner. With 100 micrograms denopamine, almost complete restoration of cardiac performance was attained, associated with a slight increase in heart rate. No arrhythmias were induced by these doses of denopamine. The results warrant clinical trials of denopamine in the treatment of cardiac failure.