British Journal of Rheumatology 0886^25]558565 AUTONOMIC DYSFUNCTION IN SYSTEMIC SCLEROSIS] TIME AND FREQUENCY DOMAIN 13 HOUR HEART RATE VARIABILITY ANALYSIS

To evaluate the autonomic nervous control of the heart in patients with systemic sclerosis "SSc# \ spontaneous heart rate variability was investigated by means of time!domain and spectrum analysis of 13 h ECG ambulatory recordings in 29 SSc patients "four males \ aged 34[1 2 8 yr \ mean2 S[D[ \ range 1659 # and 29 age!matched healthy subjects [ A signi_cantly higher heart rate "PQ 9[90 # and lower circadian and spectral indices of heart rate variability "PQ 9[90 # were observed in SSc patients \ compared with controls [ A predictive value of age "P9[991# \ tachycardia "P9[991# \ circadian heart rate variability "P9[9914 # and spectral power values "P9[994 # for patient mortality was found [ Moreover \ the relative risk of death was higher "P9[94# in older subjects with circulating anti!Scl69 [ These abnormalities \ detectable by a feasible \ non!invasive diagnostic approach\ indicate the presence of autonomic cardiac neuropathy in SSc patients[ KEY WORDS] Systemic sclerosis \ Heart involvement \ Autonomic dysfunction[ SYSTEMIC sclerosis "SSc # is a connective tissue disorder of unknown aetiology \ characterized by _brosis of the skin and visceral organs \ in which the heart is frequently and severely involved 0 \ 1 [ Scleroderma heart disease "SHD # alone or in association with interstitial lung _brosis is one of the main determinant