Secundum type atrial septal defect with prolonged PR interval and autosomal dominant mode of inheritance.

This report describes a family where secundum type atrial septal defect with prolonged atrioventricular con- duction time occurredcertainly in 6, andprobably in at least I more, members of thefamily in 3 or 4 generations. No skeletal anomalies were found. Because of a certain type of kinship in two affected branches, and an almost 50-50 distribution case among sibs and the two sexes, an autosomal dominant mode of inheritance with complete penetrance is probable.