The prevalence and prognosis of a Brugada-type electrocardiogram in a population of middle-aged Japanese-American men with follow-up of three decades

Background. The Brugada syndrome is an inherited arrhythmogenic and nonstructural heart disease associated with an increased risk of sudden cardiac death from ventricular fibrillation. There are conflicting data about its prevalence and prognosis. Particularly, population-based studies are lacking in the United States and other countries. Methods: A total of 8006 Japanese-American men aged 45 to 68 years participated in the initial examination of the Honolulu Heart Program during the period of 1965 through 1968. After excluding prevalent cases with coronary heart disease, 864 electrocardiograms coded as right bundle branch block were reviewed using the specified criteria for Brugada-type electrocardiogram. Baseline characteristics and the prognosis of Brugada-type electrocardiogram were compared with 5983 control subjects who had electrocardiograms coded as normal at the initial examination. Results: There were 12 typical cases and 11 atypical cases of Brugada-type electrocardiogram at the initial examination (prevalence, 0.15% and 0.14%, respectively). Analysis of baseline characteristics revealed no difference between control cases and either typical or atypical Brugada-type electrocardiogram cases except significantly lower body mass index in subjects with Brugada-type electrocardiogram. During the 30-year follow-up period, none of the subjects died suddenly within 24 hours after the onset of symptoms. Survival analysis revealed no significant difference between case and control groups. Conclusions: Brugada-type electrocardiograms among middle-aged or elderly Japanese-American men are uncommon and are not associated with increased risk of either sudden death or total mortality.