Does Long QT Syndrome Contribute to the Incidence of SIDS?
The sudden infant death syndrome (SIDS) is distressingly common. Despite a 30 percent decline between 1991 and 1995 for unknown reasons, the current incidence is 1/1000 during the first year of life. Etiologic possibilities include autonomic dysfunction, infection, and prone positioning. Direct physiologic observations of the event are exceedingly rare and have led to the general belief that ventricular fibrillation is not a likely precipitant. In this case report, a 6-week-old infant in previously good health was found cyanotic and pulseless. Rapid resuscitation was instituted with correction of ventricular fibrillation and restoration of sinus rhythm. Marked QTc prolongation, a cardiac repolarization abnormality associated with ventricular arrhythmias and sudden death, was observed. Genetic analysis revealed a mutation in SCN5A, the cardiac sodium-channel gene. This mutation results in a prolongation of cardiac depolarization and is associated with a heritable form of QT-interval pro
