| Abstrakt: |
Left ventricular ejection fraction, end-diastolic volume, and cardiac output measured by a radionuclide method (scintillation probe and radioactive 113mindium) in 18 men with coronary arterial disease, and the effects of administration of propranolol (two hours following oral administration of 20 mg, 40 mg, or 80 mg), of nitroglycerin (0.4 sublingually administered), and of these two drugs in combination, were measured. Administration of nitroglycerin increased the ejection fraction and decreased the end-diastolic volume and cardiac output. Therapy with propranolol (20 mg regimen) did not alter these measurements, although a 15 percent or greater decrease in the ejection fraction was observed in three of six men with an abnormal ejection fraction. Therapy with propranolol (40 mg and 80 mg regimens) decreased the ejection fraction and cardiac output and increased the end-diastolic volume. Of six men with an abnormal ejection fraction, five had a 15 percent or greater decrease after receiving the 40 mg regimen of propranolol. Administration of nitroglycerin in combination with propranolol resulted in a decrease in the end-diastolic volume and an increase in the ejection fraction, with a further decrease in the cardiac output. Therapy with propranolol was associated with a reduction in heart rate, and this drug blocked the increase in heart rate associated with administration of nitroglycerin. These results suggest that the effects of therapy with propranolol in combination with nitroglycerin favorably alter the left ventricular volume and heart rate in terms of the myocardial demand for oxygen. |
