Prevalence and clinical course of the juveniles with Brugada-type ECG in Japanese population

Background: Although many studies on Brugada syndrome have been done, with many reports of genetic findings and clinical features, little evidence exists to support the role of this syndrome in sudden cardiac death in a juvenile population. We sought to determine the prevalence and clinical course in children exhibiting Brugada-type ECG in a community-based population. Methods: Our study population comprised 21,944 subjects (11,282 boys and 10,662 girls) who underwent ECG during their first-year elementary school health examinations between 1992 and 2001 in Izumi City, Osaka. Brugada-type ECG was defined as demonstrating ST-segment elevation (coved or saddle-back type, J wave amplitude ≥0.2 mV) in the right precordial leads. We also divided Brugada-type ECGs into three types according to a consensus report. Type 1: coved ST-segment elevation displaying high J wave amplitude followed by a negative T wave; Type 2: high take-off and gradually descending ST-segment elevation (remaining ≥1 mm) followed by a positive orbiphasic T wave; and Type 3: ST-segment elevation of <1 mm of both types. Results: Four subjects showed Brugada-type ECG (0.02%) (2 boys and 2 girls). Only one subject, a girl, met Type 1 criteria (0.005%). No history of structural heart disease was documentedin these four subjects. During 6.8 ± 1.0 years of follow-up, no episode of unexpected sudden death, syncopal attack, and fatal arrhythmia occurred. Conclusions: The prevalence of Brugada-type ECG in a juvenile population was extremely low. To investigate when the typical Brugada-type ECG might be manifested, it could be necessary to check ECGs after adolescence.