Effects of Kö 1366 on the hemodynamics of the normotensive and hypertensive elderly subjects.

The hemodynamic effects of a new adrenergic beta-receptor blocking agent, Kö 1366 were investigated in normotensive and hypertensive elderly subjects. This study, in its important part, was carried out to clarify whether the intrinsic sympathomimetic activity of Kö 1366 modified the hemodynamic changes due to beta-adrenergic blocking action or not. Hemodynamic changes elicited by intravenously administered Kö 1366 (0.05 mg/Kg) were correlated with age, cardiac index, and electrocardiographic findings, respectively. With reference to age in normotensive subjects, Kö 1366 caused no significant differences in rate of changes of various hemodynamic items between 3 age groups. Normotensive elderly subjects were divided into 3 groups according to cardic index. Cardiac index decreased greatly in high cardiac index group, slightly in normal cardiac index group, whereas it increased greatly in low cardiac index group. Stroke volume index showed the same tendency as cardiac index. Hypertensive elderly subjects were, also divided into 2 groups according to cardiac index. Again, cardiac index decreased in higher cardiac index group, while it increased in lower cardiac index group, though a statistical evaluation showed only a tendency of significant difference between 2 groups. In the next, hypertensive elderly subjects were divided into 2 groups according to electrocardiographic findings of left ventricular hypertrophy. Cardiac index decreased in the subjects without electrocardiographic changes, while it increased in the subjects with electrocardiographic changes. Stroke volume index of both groups increased: a greater increase in the subjects with electrocardiographic changes and a tendency of significant difference between 2 groups was recognized. These results suggested that Kö 1366 exhibited the intrinsic symathomimetic activity on the inotropism in the hearts with depressed contractile function of both normotensive and hypertensive subjects, thereby canceling the negative chronotropic action of this agent. This could be a more advantageous point of Kö 1366 in the treatment of elderly subjects with cardiac diseases than other agents without the intrinsic sympathomimetic activity.