Preserved cardiac autonomic dynamics during sleep in subjects with spinal cord injuries

Background: Spinal cord injuries (SCI) are associated with altered cardiovascular autonomic control (CAC). Sleep is characterized by modifications of autonomic control across sleep stages; however, no data are available in SCI subjects on CAC during sleep. We aim to assess cardiac autonomic modulation during sleep in subjects with SCI.Patients and methods: 27 participants with a neurological and radiological diagnosis of cervical (Cerv, n = 12, ie, tetraplegic) and thoracic SCI (Thor, n = 15, ie, paraplegic) and healthy subjects (Controls) were enrolled. Overnight polysomnographic (PSG) recordings were obtained in all participants. Electrocardiography and respiration were extracted from PSG, divided into sleep stages [wakefulness (W), non-REM sleep (NREM) and REM] for assessment of CAC, using symbolic analysis (SA) and corrected conditional entropy (CCE). SA identified indices of sympathetic and parasympathetic modulation and CCE evaluated the degree of complexity of the heart period time series.Results: SA revealed a reduction of sympathetic and predominant parasympathetic control during NREM compared to W and REM in SCI patients, independent of the level of the lesion, similar to the Controls. in all three groups, complexity of autonomic regulation was higher in NREM compared to W and REM.Conclusions: in subjects with SCI, cardiac autonomic control changed across sleep stages, with a reduction of sympathetic and an increase of parasympathetic modulation during NREM compared to W and REM, and a parallel increase of complexity during NREM, which was similar to the Controls. Cardiac autonomic dynamics during sleep are maintained in SCI, independent of the level of the lesion. (C) 2014 Elsevier B.V. All rights reserved.NIHNational Center for Advancing Translational Sciences (NCATS)Ca Granda IRCCS Fdn, Osped Maggiore Policlin, Dept Internal Med, Milan, ItalyUniv Milan, Cardiovasc Neurosci Lab, Dept Biomed & Clin Sci L Sacco, I-20157 Milan, ItalyMayo Clin & Mayo Fdn, Dept Internal Med, Div Cardiovasc Dis, Rochester, MN USAOsped Niguarda Ca Granda, Dept Neurosci, Milan, ItalyL Sacco Hosp Vialba, Neurol Unit, Milan, ItalyUniversidade Federal de São Paulo, Inst Sci & Technol, Dept Sci & Technol, São Paulo, BrazilUniversidade Federal de São Paulo, Inst Sci & Technol, Dept Sci & Technol, São Paulo, BrazilNIH: HL65176National Center for Advancing Translational Sciences (NCATS): UL1 TR000135Web of Scienc