Effect of orally administered hydralazine on neurohumoral factors and hemodynamic response in aged patients with chronic congestive heart failure.

Abstract

The hemodynamic response to orally administered hydralazine (30 mg) was studied and the changes in neurohumoral factors in 16 aged patients with chronic congestive heart failure were examined. After a single 30 mg dose, 9 patients (group I) demonstrated a > 30% decrease in systemic vascular resistance (SVR) and a significant increase in the cardiac index (CI); 7 patients, whose SVR was decreased by < 30% (group II), showed a less marked increase in CI. After 3 days of drug administration (90 mg/day), the CI decreased in group I (P < 0.05) while it tended to increase further in group II. Pretreatment plasma norepinephrine was lower in group I than group II (P < 0.05). However, in group I, it increased after 3 days of therapy, with a concomitant increase in plasma renin activity (P < 0.01) and total plasma volume (P < 0.025). Evidently, the higher pretreatment plasma norepinephrine level in group II, suggestive of more severe derangement of left ventricular function, may be associated with a less pronounced dilatory response of the peripheral vasculature after a single dose of hydralazine, and the increase in norepinephrine in group I after 3 days of treatment may limit these patients'' late hemodynamic responses to the drug.