Coronary and Systemic Hemodynamics and the Effect of Sympathomimetic Drugs and β-adrenergic Blockade in Ischemic Heart Disease

In order to investigate the hemodynamic abnormalities, the mechanism of myocardial ischemia induced by syrnpathomimetic drugs and the effects of β-adrenergic receptor blockade in ischemic heart disease (IHD), coronary and systemic hemodynamics under various conditions were simultaneously measured in control subjects (45 cases) and in patients with IHD (28 cases). The results were as follows. 1) The resting myocardial blood flow (MBF), measured by external counting method using 86Rb, in normotensive and hypertensive patients with IHD was not significantly different from that of the control. Systemic hemodynamics, i.e., heart rate (HR), cardiac index (CI), stroke volume index (SVI), total peripheral resistance index (TPRI), cardiac effort index (CEI), cardiac work index (CWI) and stroke work index (SWI), in normotensive patients also showed no difference from the control. However, in hypertensive patients, TPRI, CEI, CWI and SWI were greater due to high blood pressure than the normotensive patients and control subjects. 2) In control subjects, MBF decreased with age and a significantly negative correlation was found between MBF and age. This correlation was also found in the control subjects and patients when viewed as a whole. 3) Following intravenous administration of isoproterenol (0.02 μg/kg/min) or adrenaline (0.1 or 0.2 μg/ kg/min), the change in MBF, HR, CI, CEI and CWI in patients were not statistically significant as compared with those of the control. There was a significantly positive correlation between the change of MBF and that of HR, CI, CEI and of CWI in the two groups as a whole, except for the change of CI in the case of isoproterenol administration. 4) Following intravenous administration of noradrenaline (0.1 or 0.2 μg/kg/min), the changes in MBF, CI and SVI were variable and insignificant, and there was no significant difference between the patients and control subjects. The degree of increase in mean arterial pressure (MAP), CEI and CWI was not significantly different in the two groups. 5) Following administration of propranolol (10 mg, i. v.), the degree of decrease of CEI was significantly greater in the patients than in the control, although that of MBF, HR, CI and CWI was not significantly different in the two groups. A significantly negative correlation was found between the basal value and the change of MBF, CT, CEI, CWI and SWI in the two groups as a whole. The effect of isoproterenol and adrenaline was almost completely inhibited by pretreatment with propranolol except for the change of MAP and TPRI in the case of adrenaline administration