Familial occurrence of electrocardiographic abnormalities of the Brugada-type.

Electrocardiographic abnormalities were pointed out in a 51-year-old Japanese male whose major complaint was dizziness. His electrocardiogram showed a complete right bundle branch block, and a prolonged His bundle-ventricle (HV) interval of 100 msec. Two members of his family died of heart disease and 3 members, including a case of sudden death, presented an abnormal electrocardiogram of the Brugada-type with persistent ST segment elevation in the right precordial leads and right bundle branch block. The signal-averaged examination was made in the children of cases that died with the diagnosis of sudden death. Four cases showed a tendency of delay in the HV interval and a positive finding in the late potential. Further studies are necessary to clarify the relationship between electrocardiographic abnormalities of the Brugada-type and atrioventricular conduction disorder as well as to clarify the genetic basis of this disorder.