Heart rate variability in facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is the third most frequent form of muscular dystrophy. Heart rate variability (HRV) analysis is a means of evaluating the activity of the autonomic nervous system. The aim of this study was to evaluate HRV in FSHD patients. Fifty-five consecutive FSHD patients were enrolled (31 men, age 26-72 years). Muscular impairment was measured using a clinical severity scale (CSS). Patients were compared with a control group of 55 healthy subjects, matched for age and sex. HRV was analyzed in the time domain and in the frequency domain. Patients showed increased spectral power of the low-frequency band. Spectral power of the high-frequency band was inversely correlated with CSS score. FSHD is associated with a slight increase in sympathetic output and with a decrease in parasympathetic output. These modifications become more evident with the progression of the disease and could increase the risk of arrhythmias and other cardiovascular events.