Long QT syndrome in children.

Long QT syndrome is a disease that can cause syncope, seizures and sudden death. From June 1990 to June 1996, 11 children (male/female: 714; ages: 1 day-13 years with a median of 5.4 years) from different families were found to have long QT syndrome. Their corrected QT intervals (QTc) were 0.46-0.59 sec (median: 0.53 sec). All patients had normal hearing. One patient had Marfan syndrome with mitral valve prolapse. The presentation symptoms were: sudden death (2), seizures (6) and syncope (3). Their electrocardiogram abnormalities included: torsades de pointes (7), sinus bradycardia (4), T wave abnormalities (4), monomorphic ventricular tachycardia (2) and congenital complete atrioventricular block (1). All patients were treated with beta-blockers and one had pacemaker implantation. In a follow-up period of 0.5-6 years, 6 were symptom free, 1 died of ventricular tachycardia and 2 had recurrent syncope.