The congenital long QT syndrome. An unusual cause of childhood seizures.

The congenital long QT syndrome is an unusual disorder characterized by Q-T interval prolongation on electrocardiogram that predisposes the heart to ventricular tachycardia and fibrillation. We describe herein four patients with the congenital long QT syndrome who initially presented with generalized seizures. Three of these children were initially misdiagnosed as having a primary seizure disorder. The causal relationship of complex ventricular arrhythmias to seizure activity was documented in each child. This experience emphasizes the importance of obtaining an electrocardiogram in all children with a seizure disorder of unknown origin.