EFFECTS OF AGING ON NEUROENDOCRINE ACTIVATION IN SUBJECTS AND PATIENTS IN THE PRESENCE AND ABSENCE OF HEART-FAILURE WITH LEFT-VENTRICULAR SYSTOLIC

The neuroendocrine profile and echocardiographic features of 40 patien ts (81 +/- 1 years, mean +/- standard error) with heart failure and im paired left ventricular systolic function were compared with those of an age-matched group of healthy subjects, 20 younger patients with hea rt failure (aged 58 +/- 1 years), and 15 younger healthy subjects. Nor mal elderly subjects had a neuroendocrine profile similar to that of h ealthy younger subjects apart from elevated plasma norepinephrine (958 +/- 84 vs 302 +/- 118 pg/ml; p < 0.001) and atrial natriuretic peptid e (40 +/- 6 vs 28 +/- 5 pg/ml; p < 0.05). Despite a similar severity o f heart failure, elderly patients had smaller ventricular dimensions ( left ventricular internal dimension in diastole 51 +/- 2 vs 69 +/- 3 m m; p < 0.0001) and greater impairment of ventricular compliance using Doppler indexes. Plasma norepinephrine wets higher (1,191 +/- 80 vs 62 0 +/- 67 pg/ml; p < 0.01), and plasma atrial natriuretic peptide, plas ma active renin, and angiotensin II were lower in the elderly than in the younger patients with heart failure. As functional capacity declin es with age, elderly patients may have less severe cardiac dysfunction for any given level of functional impairment, and this may account fo r most of the differences in neuroendocrine activity with age. Age app ears to be an important determinant of plasma norepinephrine and may b e a confounding factor in interpreting the prognostic significance of this hormone.