Assessment of autonomic nervous system function in patients with Behçet' s disease by spectral analysis of heart rate variability.

The purpose of this study was to evaluate the autonomic nervous system (ANS) function in patients with Behçet's disease by using power spectral analysis of heart rate variability (HRV). The study population consisted of 71 patients with Behçet's disease, and 26 normal volunteers. HRV was measured by power spectral analysis in supine and standing position. In supine position, Behçet's patients had increased low frequency component in absolute (LF) and normalized units (LF nU) but had lower values of high frequency component in absolute (HF) and normalized units (HF nU) than the controls (P < 0.05). In standing position, higher values were obtained in LF and LF nU but lower values of HF and HF nU in Behçet's patients than controls (P < 0.05). LF/HF was significantly higher in patients both in supine (2.5 +/- 1.0 vs. 1.2 +/- 0.8, P = 0.001) and standing (21.9 +/- 7 vs. 1.8 +/- 0.3, P < 0.001) positions. Our data suggest that patients with Behçet's disease may have asymptomatic ANS dysfunction, which is in the form of increased sympathetic and decreased parasympathetic modulation, and power spectral analysis of HRV is beneficial in assessing the ANS function.