To study the inheritance pattern of SUDS families who have abnormal ECG pattern of Brugada Syndrome. Methods: Pedigrees of SUDS families were constructed from interviewing family member of SUDS victims. The exclusion criteria are unability to undergo ECG and procainamide testing, prolong QT interval, high grade atrioventricular block, procainamide allergy, pregnancy or breast milk feeding, and children under 5 years old. We performed the standard 12-lead ECG, higher-inctercostal-space-V1 to V3-lead ECG and procainamide was administered to detect RBBB and ST elevate in V1-V3 and higher-inctercostal-space-V1 to V3-lead ECG if standard ECG did not reveal ECG pattern of Brugada Syndrome. Result: We included 89 family members (41 male and 48 female) from 4 SUDS families (family A, B, C and D). Twenty six individuals (15 male and 11 female) with ECG pattern of Brugada Syndome were identified. Two SUDS victims had family history of presumptive SUDS (family A, B). Abnormal ECG patterns of Brugada Syndrome affected were detected in either parents of SUDS victims in all families. Seven out of 17 siblings and none of offsprings of SUDS victims were affected. The "father to son transmission" inheritance pattern were found in 3 of 4 families (family A, C, D). Conclusion: Using ECG pattern of Brugada Syndrome, PSUDS and SUDS as phenotype we demonstrated that the pattern of inheritance of 4 SUDS family was most consistant with autosomal dominant.
