AUTONOMIC MODULATION OF HEART-RATE AND BLOOD-PRESSURE IN HYPERTENSIVESUBJECTS WITH SYMPTOMS OF ANXIETY

1. The influence of anxiety symptoms on autonomic nervous system cardi ovascular control has never been studied in hypertensive subjects. Thi s study was designed to verify the presence of sympathetic hyperactivi ty in hypertension associated with anxiety symptoms. 2. Neuroautonomic cardiovascular control was evaluated using short-time power spectral analysis of RR and arterial pressure variability at baseline and after the head-up tilt test. The two spectral components principally influe nced by the autonomic nervous system are the low-frequency (LF) compon ent, mainly though not exclusively due to sympathetic modulation, and the high-frequency (HF) component, due to parasympathetic activity. Th e ratio of LF to HF powers (LF:HF) provides an index of the sympathova gal sinus balance. 3. We studied 33 hypertensive subjects (mean age 47 +/- I years; M:F = 19: 14) and 37 normotensive control subjects (mean age: 47 +/- 2 years; M:F = 20: 17) divided into four subgroups: hyper tensive subjects who scored 2 or more on a 5-item anxiety symptom scal e, hypertensive subjects who scored 0, normotensive controls who score d 2 or more and normotensive controls who scored 0. LF:HF and LF durin g rest were significantly higher (P < 0.05) in hypertensive and normot ensive groups with an anxiety score of 2 or more compared with the two groups who scored 0. HF of systolic blood pressure was significantly lower in the hypertensive group who scored 2 or more than in the hyper tensive group who scored 0 (P < 0.05). Tilt in both hypertensive group s reporting anxiety symptoms left the indexes of sympathetic modulatio n unchanged. Tilt in hypertensive subjects reporting anxiety symptoms also induced a significant fall in arterial pressure (P < 0.05). The m ean left ventricular mass index was significantly higher in the hypert ensive subjects who had anxiety scores of 2 or more than in those scor ing 0 (144.7 +/- 3.0 versus 133.4 +/- 2.31, P < 0.05). 4. In conclusio n, normotensive and hypertensive subjects reporting anxiety symptoms s howed increased sympathetic modulation of heart rate at rest. Higher a nxiety scores seem to be associated with the development of left ventr icular hypertrophy.