The long QT syndrome in children

We examined 29 pediatric patients with long-Qt-syndrome in three academic hospitals. The mean age was 10 years (3-17). Of these patients 22 used betablocker therapy, in three combined with pacemaker. Genotyping has been performed in 22 children. LQTSI (mutation in the KCNQ1 gene) was found in twelve, LQTS2 (mutation in the HERG gene) in eight and LQTS3 (mutation in the SCN5Agene) in two. Patients came under attention due to bradycardia postnatally in four, after near-drowning in three and after syncope in another four patients. In most of these eleven children family history was found retrospectively to be positive for sudden cardiac death or recurrent syncope. In eighteen children the diagnosis of LQTS was made during family screening. Retrospectively, six of these children were found to have had recurrent syncope. Although LQTS is becoming a well-known disease, there still are patients that come under attention after a considerable delay. This may result in sudden cardiac death that might have been prevented. Genotyping is essential in this familial disorder. There is a relation between genotype and fenotype, thus leading to differences in therapy and advice. It is also possible to diagnose asymptomatic carriers, thus enabling secondary prevention. In conclusion, LQTS has a high mortality, which can be greatly reduced by therapy. It is therefore necessary to evaluate precisely patients and family members in the case of recurrent syncope, near-drowning or sudden cardiac death. The joint management of (pediatric) cardiologist and clinical geneticist plays an important role in diagnosis and therapy