EVALUATION OF THE SYMPATHETIC NERVOUS-SYSTEM USING HEART-RATE-VARIABILITY AND PLASMA HORMONES IN HYPERTENSIVE PATIENTS TREATED WITH CILAZAPRIL AND ATENOLOL

In a double-blind placebo-controlled parallel study, we assessed basal and post-therapeutic sympathetic activity both in supine and standing positions in mildly to moderately hypertensive patients by two differ ent methods: frequency domain indices of heart rate variability (HRV) and plasma levels of both noradrenaline (NA) and its metabolite, 3,4-d ihydroxyphenylglycol (DOPEG). Patients were evaluated on placebo and a fter 8 weeks of treatment with either cilazapril, 2.5-5 mg/day (13 pat ients) or atenolol, 50-100 mg/day (14 patients). Twenty-four-hour bloo d pressure was similarly reduced (p < 0.01) by both cilazapril and ate nolol. Heart rate decreased with atenolol by 14 beats per min (p < 0.0 01) but did not change with cilazapril. When compared to the placebo, cilazapril did not modify sympathetic activity indices of HRV but did significantly reduce NA and DOPEG levels in both the supine and standi ng (p < 0.05) positions. As expected, atenolol reduced (p < 0.05) symp athetic activity indices of HRV but did not modify NA levels in either position. Moreover, while on placebo, patients showed no significant correlations between values of NA or DOPEG, nor in any of the HRV indi ces. We conclude that: (1) the antihypertensive effects of cilazapril and atenolol are similar, but in these patients, sympathetic activity indices showed divergent results both before and after therapy; (2) th is may be due to different aspects of sympathetic activators, assessed independently by different methods, and (3) these discrepancies must be taken into account when evaluating autonomous nervous system parame ters.