Linear and non-linear assessment of heart rate variability in congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome (CCHS) is characterised by the failure of the autonomic control of breathing and is defined as a multi-system disorder with symptoms of diffuse autonomic nervous system dysfunction. The present study, considering the heart rate variability (HRV) parameters as expression of cardiac autonomic nervous system activity, reports higher heart rate (HR) levels and reduced HRV, at rest in supine position, in CCHS patient in comparison with controls. The CCHS subject presented lower values of HF spectral component and SD1 Poincaré plot parameter, indicating a decrease of vagal cardiac influence. Also the LF component and SD2 parameter were reduced, while the LF/HF ratio presented a higher value as expression of sympatho-vagal dysregulation with dominant sympathetic activity and prevalent vagal withdrawal. The fractal dimension and beta values suggest lower cardiac complexity and a probable lack of integrity of autonomic control mechanisms in CCHS subject in comparison to controls.