Ventricular fibrillation in Brugada syndrome patients occurred significantly more frequently at night than during the day (93.3% vs 6.7%, P<0.001) and during sleep than while awake.
Observational (n=12)
What is the circadian pattern of ventricular fibrillation development in patients with Brugada syndrome?
Ventricular fibrillation in Brugada syndrome occurs predominantly at night and during sleep, suggesting a role for increased nocturnal vagal activity and sympathetic withdrawal.
Absolute Event Rate: 93.3% vs 6.7%
p-value: p=<0.001
AIMS: Brugada syndrome is considered to be a distinctive subgroup of idiopathic ventricular fibrillation. Identification of the circadian pattern of ventricular fibrillation would contribute to the elucidation of its underlying pathophysiology, but this pattern remains unknown in patients with Brugada syndrome. METHODS: and Results A total of 12 consecutive Brugada syndrome patients (46+/-14 years, all male) who underwent implantation of an implantable cardioverter defibrillator were studied. The distribution of the time of ventricular fibrillation detection was examined and classified into four 6-hour time periods of the day. The mean follow-up period following implantation was 777+/-535 days. In six out of the 12 patients, ventricular fibrillation occurred during follow-up. The data logs revealed that ventricular fibrillation was detected 30 times (range, 3-9). Ventricular fibrillation was observed more frequently at night ( 1800 h to 0600 h) than in the day (0600 h to 1800 h) (93.3% 28/30 vs 6.7%2/30, P<0.001), and during sleep than while awake (86.7% 26/30 vs 13.3%4/30, P<0.001). Ventricular fibrillation occurred most frequently between midnight and 0600 h in patients with ventricular fibrillation episodes during sleep (76.9% 20/26 vs 23.1%6/26, P<0.01). CONCLUSION: These results suggest that increased nocturnal vagal activity and withdrawal sympathetic activity may play an important role in the arrhythmogenesis of the Brugada syndrome.
Kiyotaka Matsuo (1999) conducted an observational in Brugada syndrome (n=12). Observation of circadian pattern vs. Daytime or awake periods was evaluated on Distribution of the time of ventricular fibrillation detection (night vs day) (p=<0.001). Ventricular fibrillation in Brugada syndrome patients occurred significantly more frequently at night than during the day (93.3% vs 6.7%, P<0.001) and during sleep than while awake.