Incidence of İdiopathic Long QT Syndrome in Children With Congenital Deafness

Long QT syndrome is characterized by a prolongation in the QT interval, associated with a high risk for syncope and sudden death. Jervell and Lange-Nielsen had initially deseribed it in association with congenital deafness. We have investigated the incidence of this syndrome in a school for deaf children; 350 children w ith an age range of 6-19 were evaluated by ECG. Corrected QT interval was calculated by Bazett's formula. Eight children with a QTc interval greater than 0.44 see were further studied: Cardiac examination, repeated ECGs (3 times), Rolter monitoring, echocardiography and exercise tests were performed for these 8 children. The families were assessed in regard to a history of syncope and deafness, as well as a lengthened QTc interval. Two girls, aged 14 and 15, were diagnosed to have long QT syndrome according to Schwartz criteria (0.57 % among the 350 children). The first case had two major (QTc=483 see and history of syncopal attack) plus one minor criteria (congenital deafness), the second girl had two major (QTc= 613 see and family members with LQTS) plus one minor criteria (congenital deafness). Prophylactic beta bloeker therapy was started. This syndrome should be sought for in children with syncope or a family history of it, especially in children w ith loss of hearing.