Long QT syndrome in children with congenital deafness.

The Jervell and Lange Nielson syndrome(JLN) is an infrequent form of long QT syndrome (LQTS) in which prolonged QT interval and congenital deafness exist together. We attempted to identify patients with LQTS among 127 children (age 1.2 to 10 years) with congenital hearing loss. The corrected QT interval was measured from 12 lead electrocardiogram(ECG) , using Bazettes and Friedricia formulae.The QT interval was considered prolonged when it exceeded the upper limit of 440ms and 450ms, respectively. Ten children with congenital deafness had a corrected QT interval longer than 440ms. Although these children did not meet the definite criteria according to Schwartz parameters, all the 10 children could be defined as having intermediate probability of LQTS according to revised criteria. We advise that children with congenital deafness be screened for long QT syndrome.