Cardiac autonomic control in Brugada syndrome patients during sleep: the effects of sleep disordered breathing.
AIMS
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.


CONCLUSION
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.
['Tobaldini|Eleonora|E|', 'Brugada|Josep|J|', 'Benito|Begona|B|', 'Molina|Irma|I|', 'Montserrat|Josep|J|', 'Kara|Tomas|T|', 'Leinveber|Pavel|P|', 'Porta|Alberto|A|', 'Macedo|Paula G|PG|', 'Montano|Nicola|N|', 'Somers|Virend K|VK|']
D000328:Adult D000368:Aged D001341:Autonomic Nervous System D053840:Brugada Syndrome D005260:Female D006339:Heart Rate D006801:Humans D008297:Male D008875:Middle Aged D017286:Polysomnography D012890:Sleep D012891:Sleep Apnea Syndromes
Brugada syndrome Sleep Sleep disordered breathing Heart rate variability Autonomic nervous system Non-linear analysis