Plasma immunoreactive neuropeptide Y in congestive heart failure at rest and during exercise.

The purpose of the study described here was to study plasma immunoreactive Neuropeptide Y (NPY) at rest and during exercise in patients with congestive heart failure (CHF) and in healthy subjects. Thirty-five patients, mean age 64 years, with CHF in optimal treatment and with a mean ejection fraction of 32%, were studied at rest and during exercise. Twelve age and sex matched healthy subjects were compared for resting values. Another nine healthy subjects were studied at rest and during exercise at a constant low load of 75W and at a high load defined as 80% of their individual maximal capacity. In patients with congestive heart failure mean plasma immunoreactive NPY at rest was 10.3 pmol l-1 and was not significantly different from the control group. No differences between patients with slight and severe CHF were found and there was no correlation between plasma immunoreactive NPY and left ventricular ejection fraction. Mean maximal exercise time was on average 6.3 min. Only three patients exercised more than 10 min. At maximal exercise mean plasma immunoreactive NPY was 10.6 pmol l-1 the same as at rest. Plasma noradrenaline was increased in CHF patients compared to healthy subjects, and rose further during exercise. In healthy subjects plasma immunoreactive NPY rose significantly on both workloads, but more on the high load (p < 0.05), when the rise was first significant after 10 min. Plasma immunoreactive NPY at rest and during exercise was not increased in CHF patients in optimal medical treatment. Consequently plasma immunoreactive NPY is not a useful marker of the severity of CHF in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)