Preliminary cardiological examinations in deaf children.

There is some evidence that deaf children are more threatened than the general population by dangerous heart arrhythmias. An example is Jervell-Lange-Nielsen syndrome (one of the forms of long QT syndrome) which is characterised primarily by congenital deafness and prolongation of the QT interval. The aim of this study was to perform preliminary cardiological examinations on 162 deaf children (76 girls and 86 boys, 3-15 years old, mean age 10.5 +/- 2.8 years) who attend the Regional School Centre for Deaf Children in Katowice. The data in our analysis was obtained from case histories (school records and special questionnaires sent to parents), physical examinations with special regard to the cardiovascular system, double blood pressure measurement and 12 lead surface electrocardiogram. In the studied group, 90 children (55.5%) were congenitally deaf. Within this group, 24 children manifested tachycardia while 4 children manifested-bradycardia. A-V block of I degree was found in 3 children. Incomplete right bundle branch block (RBBB) was observed in 44 children while a complete RBBB was noticed in 1 child. QTc interval was prolonged (> 0.44s) in 12 children suffering from congenital form of deafness and in 16 children suffering from all causes of deafness. On the basis of case history, physical examination, and standard 12-lead electrocardiogram, we established the occurrence of risk factors according to the new diagnostic criteria of Schwartz et al. with relative points assigned to the electrocardiographical, clinical and familial findings. These points when summed up represent the risk of sudden death caused by ventricular arrhythmia due to long QT syndrome. In the studied group (according to the Schwartz criteria), 2 (1.2%) children had high probability (> or = 4 points) of long QT syndrome (LQTS), 25 (15.4%) children had intermediate probability of LQTS (2-3 points) and 135 children had low probability of LQTS (< or = 1 point).