The hemodynamics and hemodynamic effects of indenolol in mild hypertension.

For clarifying the onset mechanism of essential hypertension, the hemodynamics in 9 mildly hypertensive men, mean age of 39.8 +/- 10.7 (mean +/- SD), was compared with 7 normotensive men, mean age of 39.8 +/- 10.7, by means of exercise echocardiography, and the effects of indenolol (administered 30 mg/day for 7 days orally to both groups) were studied. The interventricular septum and the left ventricular posterior wall were thickened in the mild hypertensives. No significant differences between the both groups were shown in the cardiac performance at rest and the cardiac index during exercise. The total peripheral vascular resistance was higher in the mild hypertensives than the normotensives during exercise. However, during exercise, the normotensives showed significant increases in the left ventricular end-diastolic dimension (LVDd) and the stroke index (SI); these changes were not significant in the mild hypertensives. After administration of indenolol, the significant increases in LVDd and SI during exercise were observed in the mild hypertensives. This study suggests that mild hypertensives with cardiac hypertrophy display a diminished Frank-Starling effect during exercise which may be attributed to the decreased left ventricular compliance due to cardiac hypertrophy and elevated afterload. Indenolol improved the Frank-Starling effect, which decreased in the mild hypertensives.