Congenital long QT syndrome: diagnosis and management in pediatric patients.

The long QT syndrome (LQTS) is characterized by electrocardiographic abnormalities and a high incidence of syncope and sudden cardiac death (SCD). The diagnosis is suggested when ventricular repolarization abnormalities result in prolongation of the corrected QT interval. When LQTS is suspected, genetic screening may identify a specific long QT subtype and provide guidance for appropriate therapy. Treatment depends on the relative risk of SCD, which is increased with longer QT durations, prior cardiac events, and a family history of SCD. beta Blockers are considered the initial treatment of choice, with implantable cardioverter-defibrillator (ICD) therapy warranted in high-risk patients. In patients with frequent ICD shocks or in those at high risk for SCD where ICD placement cannot be performed, cardiac pacing and/or left cardiac sympathetic denervation may be indicated.