Effects of nipradilol (K-351) on cardiac function in anesthetized open-chest dogs.

Effects of nipradilol (K-351) on cardiac performance and myocardial oxygen consumption were investigated in anesthetized open-chest dogs. Nipradilol 0.1 mg/kg i.v. induced falls in systolic and diastolic aortic blood pressure and left ventricular pressure, and decreases in cardiac output, coronary sinus outflow, left ventricular dP/dt and heart rate. Stroke volume was transiently increased and left ventricular stroke work index was significantly decreased, while left ventricular mechanical efficiency was not significantly changed. Myocardial oxygen consumption was significantly decreased. Total peripheral vascular resistance and coronary vascular resistance were persistently increased. Left ventricular enddiastolic pressure was not significantly changed. These results suggest that nipradilol has a possible antianginal property through a decrease in myocardial oxygen consumption due to a fall in aortic blood pressure and a decrease in heart rate.