Cardiac autonomic profile in rheumatoid arthritis and systemic lupus erythematosus

Neurological involvement is a well-documented issue in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). However, little is known about the involvement of the autonomic nervous system. This study was conducted to investigate autonomic nervous system dysfunction in patients with RA and SLE. Twenty-six RA patients, 38 SLE patients and 40 healthy controls were recruited from our in- and out-patient departments. Heart rate variability (HRV) parameters (the power of the high- [HF] and low-frequency [LF] band of haemodynamic time series, the ratio between low- and high-frequency components [LF/HF ratio], the power spectral density), baroreflex sensitivity (BRS) and beat-to-beat blood pressures were assessed by a novel non-invasive haemodynamic monitoring tool (Task Force Monitor [TFM], CNSystems Medizintechnik GmbH, Graz, Austria). Autonomic nervous system dysfunction was determined according to classical Ewing autonomic test battery. Furthermore, we implemented a secondary autonomic test score by modifying the Ewing test battery with additional criteria. Both the classical and modified Ewing test batteries have revealed that the frequencies of autonomic neuropathy were significantly higher in patient groups compared with controls (p < 0.001). Evaluation by TFM revealed that deterioration of sophisticated autonomic parameters (such as HRV and BRS) were more pronounced in the patient groups compared with controls. There was a significant association between BRS and Ewing test scores and abnormal BRS results were more frequent in patients with autonomic dysfunction according to Ewing test batteries. No relation was found between autonomic neuropathy and disease duration, disease activity and autoantibody positivity. Consequently, we believe that further large-scale studies investigating cardiovascular autonomic neuropathy in rheumatic diseases should be carried out to verify our findings and manifest clinical consequences beyond these results.