Repeat hemodynamic determinations in borderline hypertension

Abstract

Repeat hemodynamic determinations were performed in 37 young men with borderline hypertension. The duration of the follow up study was 47 ± three months. At each determination, those with borderline hypertension were compared to a group of matched normal subjects. Blood pressure increased from the first to the second determination, but the increase was significant only for systolic (P < 0.001) and mean (P < 0.01) arterial pressures. Cardiac index and heart rate, which were initially increased, decreased significantly (P < 0.02; P < 3.01, respectively) and decreased to normal values; total peripheral resistance increased (P < 0.01); blood and plasma volumes decreased (P < 0.01). At the first determination, the cardiac index-heart rate correlation was significant (P < 0.01) and the cardiac index-blood volume correlation was not. At the second determination, on the contrary, the cardiac index-total blood volume correlation was significant (P < 0.001) whereas the cardiac index-heart rate correlation was not. The study provides evidence that patients with borderline hypertension, over a short-term period, show (1) a greater increase in systolic than in diastolic pressure, (2) a return of cardiac output toward normal values through a decrease both in heart rate and blood volume, and (3) an increased importance of volume factors in the cardiac output control.