Heritable channelopathies that include congenital long QT syndrome (LQTS), Brugada syndrome (BrS), and catecholaminergic polymorphic ven tricular tachycardia (CPVT) affect an estimated 1 in 2000 persons, may present with syncope or sudden cardiac death, and often elude detection by standard 12-lead electrocardiography (ECG). In LQTS, an estimated 40% of genetically affected subjects have concealed LQTS with a normal or borderline heart rate corrected QT interval (QTc) at rest. A significant proportion of patients with BrS has concealed BrS with no evidence of a type 1 Brugada electrocardiographic pattern at rest. Every patient with CPVT has a normal resting ECG. Provocative testing with catecholamines and pharmacological testing with sodium channel blockers are critical diagnostic tests in the evaluation of these channelopathies and can help unmask LQTS, BrS, and CPVT in their concealed state. The role of these provocative tests in the evaluation of inherited arrhythmia syndromes will be reviewed in this chapter.
|Original language||English (US)|
|Title of host publication||Electrical Diseases of the Heart|
|Subtitle of host publication||Genetics, Mechanisms, Treatment, Prevention|
|Number of pages||10|
|State||Published - Dec 1 2008|
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