FAMILIAL SICK SINUS SYNDROME IN 2 SIBLINGS

Two siblings with sinus node disease are presented. The patients were severely affected and required permanent pacing. A cardiac electrophys iologic study was conducted in Case 2, which revealed an atrioventricu lar conduction disturbance in addition to sinus node dysfunction. The parents and other siblings showed no evidence of sinus node disorder. The occurrence of this disease in these siblings suggests an autosomal dominant mode of inheritance with variable penetrance.