CARDIOVASCULAR EFFECTS OF BRAIN NATRIURETIC PEPTIDE IN ESSENTIAL-HYPERTENSION

We evaluated the cardiovascular effects of pathophysiological plasma l evels of brain natriuretic peptide in seven patients with mild to mode rate essential hypertension by performing equilibrium radionuclide ang iocardiography at baseline and during brain natriuretic peptide infusi on at increasing doses (4, 8, 10, and 12 pmol/kg per minute for 20 min utes each). Brain natriuretic peptide induced a progressive reduction of left ventricular end-diastolic volume (from 107.5+/-10.3 to 89.0+/- 11.0 mL at the end of all infusion periods) and end-systolic volume, w hereas stroke volume did not show any significant change (from 64.9+/- 5.9 to 62.7+/-7.8 mL). Cardiac output, arterial pressure, and peripher al vascular resistance did not change significantly. The lack of effec ts on systemic hemodynamics was probably due to compensatory activatio n of the sympathetic nervous system, as indicated by the significant i ncrease in plasma norepinephrine levels (from 1.75+/-0.18 to 2.19+/-0. 21 nmol/L), heart rate (from 68+/-6 to 81+/-6 beats per minute), peak ejection rate, and peak filling rate. These results indicate that brai n natriuretic peptide, at the pathophysiological plasma concentrations reached in this study, influences cardiovascular homeostasis mainly b y reducing cardiac preload.