title: Cardiac autonomic control in Brugada syndrome patients during sleep: the effects of sleep disordered breathing.
abstract: OBJECTIVE
  Brugada syndrome is characterized by typical ECG features, ventricular arrhythmias and sudden cardiac death (SCD), more frequent during nighttime. Autonomic cardiovascular control has been implicated in triggering the ventricular arrhythmias. Sleep-disordered breathing (SDB) elicits marked autonomic changes during sleep and is also associated with an increased risk of nighttime SCD. Brugada patients may have a higher likelihood of SDB compared to controls. However, no data are available on cardiac autonomic control in Brugada patients, particularly with regard to the comorbidity of SDB.
  
  
  METHODS
  We evaluated autonomic cardiovascular control in Brugada patients with SDB (BRU-SDB, n=9), without SDB (BRU, n=9), in controls (CON, n=8) and in non-Brugada patients with SDB (n=6), during wakefulness and sleep (N2, N3 and REM). Linear spectral and entropy-derived measures of heart rate variability (HRV) were performed during apnea-free stable breathing epochs.
  
  
  RESULTS
  Total HRV was attenuated in BRU-SDB compared to CON and BRU. During N2 and REM, in BRU-SDB patients sympathetic modulation decreased compared to BRU and CON, while during REM, they showed an increased parasympathetic modulation, compared to the other two groups. BRU-SDB and SDB were similar in terms of spectral components. Entropy-derived indices showed preserved dynamic changes in Brugada patients compared to controls through the different sleep stages.
  
  
  CONCLUSIONS
  Brugada syndrome per se does not appear associated with an altered autonomic cardiovascular control during wakefulness and sleep. The comorbidity with SDB may contribute to disrupted autonomic cardiovascular regulation during sleep, possibly predisposing to the increased likelihood of sleep-related ventricular tachyarrhythmias and SCD.
authors.affiliation: Department of Biomedical and Clinical Sciences, Internal Medicine II, L. Sacco Hospital, University of Milan, Italy; Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN, USA.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Tobaldini
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
authors.forename: Begona
authors.initials: B
authors.lastname: Benito
authors.forename: Irma
authors.initials: I
authors.lastname: Molina
authors.forename: Josep
authors.initials: J
authors.lastname: Montserrat
authors.forename: Tomas
authors.initials: T
authors.lastname: Kara
authors.forename: Pavel
authors.initials: P
authors.lastname: Leinveber
authors.forename: Alberto
authors.initials: A
authors.lastname: Porta
authors.forename: Paula G
authors.initials: PG
authors.lastname: Macedo
authors.forename: Nicola
authors.initials: N
authors.lastname: Montano
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000502:physiology; D053840:Brugada Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*
keywords: Autonomic nervous system; Brugada syndrome; Heart rate variability; Non-linear analysis; Sleep; Sleep disordered breathing