Autonomic modulation of heart rate and blood pressure in hypertensive subjects with symptoms of anxiety.

1. The influence of anxiety symptoms on autonomic nervous system cardiovascular control has never been studied in hypertensive subjects. This study was designed to verify the presence of sympathetic hyperactivity 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 influenced by the autonomic nervous system are the low-frequency (LF) component, mainly though not exclusively due to sympathetic modulation, and the high-frequency (HF) component, due to parasympathetic activity. The ratio of LF to HF powers (LF:HF) provides an index of the sympathovagal sinus balance. 3. We studied 33 hypertensive subjects (mean age 47+/-1 years; M:F=19:14) and 37 normotensive control subjects (mean age: 47+/-2 years; M:F=20:17) divided into four subgroups: hypertensive subjects who scored 2 or more on a 5-item anxiety symptom scale, hypertensive subjects who scored 0, normotensive controls who scored 2 or more and normotensive controls who scored 0. LF:HF and LF during rest were significantly higher (P<0.05) in hypertensive and normotensive 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 hypertensive group who scored 0 (P<0.05). Tilt in both hypertensive groups reporting anxiety symptoms left the indexes of sympathetic modulation unchanged. Tilt in hypertensive subjects reporting anxiety symptoms also induced a significant fall in arterial pressure (P<0.05). The mean left ventricular mass index was significantly higher in the hypertensive subjects who had anxiety scores of 2 or more than in those scoring 0 (144.7+/-3.0 versus 133. 4+/-2.31, P<0.05). 4. In conclusion, normotensive and hypertensive subjects reporting anxiety symptoms showed increased sympathetic modulation of heart rate at rest. Higher anxiety scores seem to be associated with the development of left ventricular hypertrophy.