Postprandial augmentation of bradycardia-dependent ST elevation in patients with Brugada syndrome.
BACKGROUND
In patients with Brugada syndrome, the circadian variation of ST elevation could be modulated by the autonomic nervous activity and RR interval. Recently, glucose-induced insulin secretion was also reported to contribute to fluctuation of ST elevation. Therefore, we assessed the effects of taking meals on the ST-RR relationship in the daily life of patients with Brugada syndrome.


RESULTS
Twenty-eight patients with Brugada syndrome, who had the type I ST elevation, were categorized into 12 symptomatic and 16 asymptomatic patients. Unipolar lead (V2) Holter ECG was recorded and ST-RR relationships for a 2-hour period were compared before and after each meal. From ST-RR linear regression lines, ST-RR slope (mm/sec) and ST(mm) at RR intervals of both 0.6 seconds and 1.2 seconds (ST(0.6) and ST(1.2)) were determined. The ST-RR slope increased significantly after lunch (2.6 +/- 0.4 vs 4.4 +/- 1.2, P < 0.05) and dinner (2.1 +/- 1.0 vs 5.2 +/- 1.9, P < 0.01) in symptomatic patients, but not in asymptomatic patients. In both groups, ST(0.6) was not different before or after each meal. However, ST(1.2) increased after each meal in symptomatic patients. After dinner, ST(1.2) was significantly higher in symptomatic patients than in asymptomatic patients (5.0 +/- 2.7 vs 3.6 +/- 0.8, P < 0.05). Postprandial increase in both ST-RR slope and ST(1.2) was greatest at dinner in symptomatic patients; however, this tendency was not seen in asymptomatic patients.


CONCLUSIONS
In symptomatic patients with Brugada syndrome, bradycardia-dependent augmentation of ST elevation was enhanced for the postprandial period, especially after dinner. This could be related to occurrence of ventricular fibrillation in the late evening.
Mizumaki
Koichi
K
Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan. kmizu@med.u-toyama.ac.jp
Fujiki
Akira
A
Nishida
Kunihiro
K
Iwamoto
Jotaro
J
Sakamoto
Tamotsu
T
Sakabe
Masao
M
Tsuneda
Takayuki
T
Sugao
Masataka
M
Inoue
Hiroshi
H
D000328:Adult; D001919:Bradycardia / Q000503:physiopathology*; D053840:Brugada Syndrome / Q000503:physiopathology*; D002940:Circadian Rhythm; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D019518:Postprandial Period