Heart Rate Variability during Wake and Sleep in Huntington’s Disease Patients: An Observational, Cross-Sectional, Cohort Study

Abstract

Introduction: Autonomic dysfunction has been reported as one of nonmotor manifestations of both presymptomatic and manifest Huntington’s disease (HD). The aim of our study was to evaluate heart rate variability (HRV) during wake and sleep in a cohort of patients with manifest HD. Methods: Thirty consecutive patients with manifest HD were enrolled, 14 men and 16 women, mean age 57.3 ± 12.2 years. All patients underwent full-night attended video polysomnography. HRV was analyzed during wake, NREM sleep, and REM sleep, in time and frequency domain. Results were compared with a control group of healthy volunteers matched for age and sex. Results: During wake, HD patients presented significantly higher mean heart rate than controls (72.4 ± 9.6 vs. 58.1 ± 7.3 bpm; p < 0.001). During NREM sleep, HD patients showed higher mean heart rate (65.6 ± 11.1 vs. 48.8 ± 4.6 bpm; p < 0.001) and greater low frequency (LF) component of HRV (52.9 ± 22.6 vs. 35.5 ± 17.3 n.u.; p = 0.004). During REM sleep, we observed lower standard deviation of the RR interval in HD subjects (3.4 ± 2.2 vs. 3.7 ± 1.3 ms; p = 0.015). Conclusion: Our results show that HD patients have higher heart rate than controls, during wake and NREM, but not during REM sleep. Among HRV parameters, the most relevant difference regarded the LF component, which reflects, at least partially, the ortho-sympathetic output. Our results confirm the involvement of autonomic nervous system in HD and demonstrate that it is evident during both wake and sleep.