Long QT syndrome

Abstract

The long QT syndrome is a potentially lethal electric disorder of the heart, characterized by a transient or permanent prolongation of the QT interval, carrying a risk for syncope, due to torsade de pointes and / or for sudden cardiac death, secondary to ventricular fibrillation. It comprises a congenital form and an acquired one. Th e congenital form has a genetic background, representing one of the several channelopathies, as an inherited dysfunction of a ion channel or of a regulatory protein is their common denominator.Th e acquired form has an extrinsic cause, usually a QT prolonging drug, an electrolyte imbalance or a bradyarrhythmia, possibly occuring in individuals with low penetrance of the congenital type. Th e genetic classification, the mechanisms for arrhythmogenesis, as well as the principles of management, tailored to the categories at risk, are presented.