Long QT Syndrome

**Semantic type:** Disease or Syndrome

**Definition:** A ventricular arrhythmia characterized by a long QT interval, and accompanied by syncopal episodes sometimes leading to sudden death due to paroxysmal ventricular arrhythmia. This arrhythmia is associated with a prolongation of repolarization following depolarization of the cardiac ventricles. The prolongation of the Q-T interval combined with torsades de pointes manifests as several different forms; some may be acquired or congenital; some may lead to serious arrhythmia and sudden cardiac death.

**Synonyms:** - LONG QT SYNDROME - Ventricular arrhythmia associated with long QT syndrome