Alterations of the sympathovagal balance evaluated by heart rate variability in a rare case of adult Still's disease.

We present a rare case of adult Still's disease with cardiac involvement (myocarditis and coronary arteritis). The autonomic nervous system function was evaluated by heart rate variability (HRV) analysis performed by 24-hour electrocardiographic recording during the acute phase of the disease and the remission (after 1 month and 1 year). The HRV parameters were studied in the time (standard deviation of all NN intervals-total power - SDNN, square root of the mean of the sum of the squares of the differences between adjacent NN - RMS-SD and HRV index) and frequency domains (low frequency, high frequency, and low frequency/high frequency). The results of the analysis of the HRV highlight that in the acute phase of the disease with cardiac involvement the autonomic nervous system is globally altered, with modifications of the sympathovagal balance, due to impairment of the parasympathetic component. This trend tends to persist in the short period (1 month), but seems to resolve completely within 1 year. An altered sympathovagal balance should be considered as a possible marker of vasculitis-related ischemia.