Sympathetic skin response and R-R interval variation in rheumatoid arthritis. Two simple tests for the assessment of autonomic function.

Autonomic nervous system involvement with peripheral neuropathy is a well known complication of rheumatoid arthritis (RA). In the assessment of autonomic function of patients with rheumatoid arthritis, we performed sympathetic skin response (SSR) and R-R interval variation (RRIV) tests in 30 patients and in 30 normal controls. Of 30 patients, 5 had complaints of clinical dysautonomic symptoms. SSRs were abnormal in 6 of 30 patients, whereas 8 showed abnormal RRIVs during deep breathing. Nine of 30 patients also showed electrophysiologic evidence of peripheral neuropathy. All 5 of the patients with clinical dysautonomic symptoms showed abnormal SSR and RRIV test results. No patients with normal results on both tests had clinical dysautonomia. This study showed that there are frequent abnormalities in SSR and RRIV tests in patients with rheumatoid arthritis whether there is a clinical symptom of autonomic dysfunction or not.