Prevalence of Idiopathic Long QT Syndrome in Children with Congenital Deafness

Abstract

Long QT syndrome (LQTS) is characterized by prolongation of the QT interval associated with a high risk for syncope and sudden death. Jervell and Lange-Nielsen initially described LQTS in association with congenital sensorineural deafness. We have investigated the prevalence of this syndrome in a school for deaf children, evaluating by ECG 350 congenitally deaf children with an age range of 6-19 years. The corrected QT interval (QTc) was calculated by Bazett's formula. Eight children with a QTc interval >440 ms were further studied by cardiac examination, repeat ECGs (three times), Holter monitoring, echocardiography, and exercise testing. The families were assessed for a history of syncope and deafness and underwent ECG evaluations regarding lengthened QTc interval. Among these eight children only two girls aged 14 and 15 years were diagnosed as having LQTS according to Schwartz's criteria (0.57% of the 350 deaf children; 95% confidence intervals 0, </= p </= 0.013). The first patient had two major criteria (QTc 483 ms and a history of syncopal attack) and one minor criteron (congenital deafness); the second also had two major criteria (QTc 613 ms and family members with LQTS) and one minor criterion (congenital deafness). Prophylactic beta-blocker therapy was started in these two patients to prevent sudden death. In conclusion, this syndrome should be sought in children with syncope or a family history of it, especially those with congenital deafness.

Syndromic etiology in children at schools for the deaf in Turkey

“…Hanioglu-Kargi et al [29] found in an ophthalmologic screen of deaf pupils one Waardenburg, 1 Usher syndrome in 104 Turkish deaf pupils. Ocal et al [30] found 2 Jervell Lange Nielsen syndrome in cardiologically screened 350 Turkish deaf pupils. In our study, syndromic etiology was found in 18.0% of the entire study group and 28.61% of those with genetic etiology.…”

The frequency of congenital long QT syndrome based on new formula in children with sensori-neural hearing loss

“…Finally, two girls aged 14 and 15 were diagnosed with LQTS. [19] In our study, due to lack of repeated access to the patients, their ECG records available were only studied. However, in some studies, genetic analysis was conducted regarding LQTS and the patients' genotypes were studied regarding LQTS.…”

QTc prolongation in patients with hearing loss: Electrocardiographic and genetic study

“…Furthermore, there has been a study published on 132 children with a hearing loss, among who 5 (3.8%) patients were diagnosed with JL-N syndrome [8]. On the other hand, in 350 Turkish children with congenital hearing loss, who were between the ages of 6 and 19 years, LQTS (according to Schwartz criteria) was present in only 2 (0.57%) patients (girls aged 14 and 15 years) [9]. In that Turkish study, the population of children was older than in our study.…”