Beneficial effects of bucindolol in a canine model of pentobarbital-induced heart failure.

Heart failure was induced in barbital-anesthetized dogs by administering high doses of pentobarbital. This procedure depresses cardiac function as indicated by a reduction in right ventricular contractile force (RVCF), left ventricular dp/dt and aortic blood flow. Bucindolol (0.1 mg/kg and 0.1 mg/kg/hr) elicited a pronounced and prolonged stimulant effect on these depressed indicators of cardiac function. Both RVCF and aortic blood flow returned to pre-failure levels, left ventricular dp/dt increased 43% but heart rate was elevated only slightly (14%). Total peripheral resistance was lowered 36% by bucindolol. The combination of myocardial stimulation and vasodilatation which contributed to the positive results in this acute model of pump failure suggests a possible role for bucindolol in the clinical management of congestive heart failure. Further these results suggest that bucindolol, in contrast to propranolol, could also be used in a sub-group of hypertensive patients with depressed cardiac function.