Heart rate variability in patients with Sjogren's syndrome

Heart rate variability (HRV) gives information about sympathetic-parasympat hetic autonomic balance. Our purpose was to determine whether HRV is abnorm al in patients with Sjogren's syndrome. In 16 patients with Sjogren's syndr ome and 30 matched controls, a short time analysis of HRV was performed for both the frequency and the time domain. In the time domain, patients tende d to display a slower heart rate, greater R-R variability and higher standa rd deviation of the mean (SDNN) than did healthy subjects, but the differen ces were not statistically significant. In the frequency domain the spectra l measures of HRV showed a slight reduction of LF and an increase of HF; as a result, the ratio between high and low frequencies, representative of sy mpathovagal modulation, was significantly reduced. Our data suggest an incr ease in the parasympathetic control of heart rate in patients with Sjogren' s syndrome. This predominance in vagal tone could exert a protective and an tiarrhythmic role in patients with primary Sjogren's syndrome, and may be r elevant with reference to the lower incidence of sudden death in this disor der compared to other major autoimmune diseases.