Spectral analysis of heart rate variability in treated and untreated patients with essential hypertension

By using the method of spectral analysis of heart rate variability, the function of the automatic nervous system was assessed in three groups of patients with essential hypertension: a group of newly discovered, as yet untreated patients; a group of patients chemically treated with atenolol (a beta blocker) only; and a group of patients under chronic treatment with nifedipine (a calcium antagonist) only. Results were compared to those obtained with a group of healthy control subjects of comparable age. While no significant differences were found between control subjects and untreated patients, a depression of indices of sympathetic activity in atenolol-treated patients corroborates the hypothesis that a central mechanism of action contributes to the hypotensive action of atenolol. On the other hand, chronic treatment with nifedipine did not appreciably modify the sympathovagal balance