The prevalence of Brugada's electrocardiographic (ECG) pattern in 7,022 male adolescents in the seventh grade was determined, and the some subjects were reexamined 3 years later, while in tenth grade. Two subjects (0.03%) and 7 subjects (0.10%) showed Brugada's ECG pattern by the conventional criterion (J point or ST-segment greater than or equal to0.1 mV in leads V-1 to V-3), and no subjects (0%) and 2 subjects (0.03%) fulfilled the recent criterion (J point or ST-segment greater than or equal to0.2 mV) in the seventh and tenth grades, respectively, indicating that Brugada's ECG pattern begins to appear during junior high school and increases until late adulthood. (C) 2004 by Excerpta Medica, Inc.