Clinical profile and genetic basis of Brugada syndrome in the Chinese population

NS Mok, SG Priori, C Napolitano, KK Chan, R Bloise, HW Chan, WH Fung, YS Chan, WK Chan, C Lam, NY Chan, HH Tsang
Department of Medicine and Geriatrics, Princess Margaret Hospital, Laichikok, Hong Kong

OBJECTIVE. To study the clinical profile and genetic basis of Brugada syndrome in Chinese patients.

DESIGN. Prospective observational study.

SETTING. Seven regional public hospitals, Hong Kong.

MAIN OUTCOME MEASURES. The clinical and follow-up data of 50 patients (47 men, 3 women; mean age, 53 years) were collected, and genetic data of 36 probands and eight family members of three genotyped probands were analysed.

RESULTS. Eight patients survived sudden cardiac death (group A), 12 had syncope of unknown origin but no sudden death (group B), and 30 were asymptomatic before recognition of Brugada syndrome (group C). Programmed electrical stimulation induced sustained ventricular arrhythmias in 88% (7/8), 82% (9/11), and 27% (3/11) of patients in group A, group B, and group C, respectively. New arrhythmic events occurred in 50% (4/8) of patients in group A and 17% (2/12) of patients in group B after a mean follow-up period of 30 (standard deviation, 13) months and 25 (7) months, respectively. All group C patients remained asymptomatic during a mean follow-up period of 25 (standard deviation, 11) months. Five of 36 probands and three of eight family members who underwent genetic testing were found to have a mutation in their SCN5A gene.

CONCLUSIONS. Chinese patients with Brugada syndrome who are symptomatic have a high likelihood of arrhythmia recurrence, whereas asymptomatic patients enjoy a good short-term prognosis. The prevalence of SCN5A mutation among probands is 14%. Thus, Chinese patients with Brugada syndrome share with their western counterparts similar clinical and genetic heterogeneity.

Hong Kong Med J 2004;10:32-7

Key words: Arrhythmia; Chinese; Death, sudden, cardiac; Genetics; Recurrence