Central hemodynamics and cardiac output control in essential hypertensive patients.

Central hemodynamics were determined in 202 men including 101 normotensive and 101 permanent essential hypertensive patients of the same age. Cardiac output was identical in the two groups while blood pressure and total peripheral resistance were significantly different. Strong differences between the two groups are revealed by a systematic correlation study: (i) correlations of blood pressure (with respectively heart rate and total blood volume) were significant in the normotensive group but not in the hypertensive group; (ii) correlations of cardiac output (with respectively heart rate and total blood volume) were significant in both groups; (iii) correlations of renal blood flow (with respectively cardiac output and blood pressure) were significant in the hypertensive group but not in the normo tensive group. This study provided evidence that the volume and neural pressure controls are impaired in hypertensive patients while the cardiac output control is maintained and, suggested the existence of adaptive mechanisms involving the kidney in the maintenance of normal cardiac output in permanent essential hypertensive patients.