Aortic input impedence and neurohormonal activation in patients with mild to moderate chronic congestive heart failure.

Abstract

The aim was to investigate the interrelation between pulsatile components (assessed by determination of aortic input impedance) and neurohormonal activation in chronic congestive heart failure. Aortic input impedance, plasma noradrenaline, renin, atrial natriuretic factor, and arginine vasopressin were measured in 20 patients with mild to moderate chronic congestive heart failure (coronary artery disease n = 12, idiopathic dilated cardiomyopathy n = 8). Cardiac index [2.2(SEM 0.3) litre.min-1.m-2] and left ventricular ejection fraction [38(4)%] were reduced, and pulmonary wedge pressure was increased [21(2) mmHg]. Plasma concentrations of noradrenaline [462(62) pg.ml-1], renin [12(4) ng AI.ml.h-1], atrial natriuretic factor [408(64) pg.ml-1], and--to a slight degree--arginine vasopressin [1.1(0.3) pg.ml-1] were increased. Characteristic impedance Zc [80(6) dyne.s.cm-5) and relative oscillatory aortic input pressure power [10(1)%]--both reflecting the pulsatile components of left ventricular afterload--were within the normal range. There was no significant correlation between these variables and the degree of neurohormonal activation (r values: -0.05 to -0.35). The data show that in patients with mild to moderate chronic congestive heart failure there is no interrelationship between the degree of neurohormonal activation and pulsatile components of left ventricular afterload. This may indicate that in these stages of heart failure there are no trophic effects of stimulated neurohormonal systems on the physical properties of the great arteries.