Cardiac causes of sudden unexpected death in children and their relationship to seizures and syncope: Genetic testing for cardiac electropathies
Ackerman MJ (2005) Cardiac causes of sudden unexpected death in children and their relationship to seizures and syncope: Genetic testing for cardiac electropathies. Semin Pediatr Neurol 12:1 52–8.
Abstract:The sentinel descriptions of congenital long QT syndrome (LQTS) under the eponyms of Jervell and Lange-Nielsen syndrome and Romano-Ward syndrome were provided in 1957 and the early 1960s. In 1995, the discipline of cardiac channelopathies was birthed formally with the landmark discoveries of cardiac channel mutations as the pathogenic basis for LQTS. Over the past decade, the discipline has expanded considerably being comprised of at least a dozen distinct heritable arrhythmia syndromes, several disease-susceptibility genes, and hundreds of implicated mutations. Previously confined to the purview of research testing, diagnostic genetic testing for several channelopathies is now available for routine clinical use.
Keywords: Long QT Syndrome, genetic testing, ion channels, sudden death
Context
Review of congenital cardiac channelopathies (or, more broadly, 'electropathies', as some mutations discussed are not in ion channels) leading to cardiac syndromes including long QT, Brugada, Timothy, and others. An abnormality in repolarization can, in the presence of an unexpected stimulus occurring at a certain point in the cardiac cycle, lead to torsades de pointes. This can lead to syncope and seizure or seizure-like behavior, and individuals with long QT syndrome have been diagnosed with a generalized seizure disorder and placed on anticonvulsant medication. Torsades de pointes can alternatively lead to syncope and death. Hence it is possible that rare deaths ascribed to SUDEP could actually be occurring in individuals misdiagnosed with epilepsy, through a mechanism of this type. If torsades leads to generalized seizure the mechanism is not clear.