Long QT syndrome

An inherited condition involving mutations that affect ion channels important in myocardial repolarisation.

May also be acquired secondary to drugs, electrolyte imbalances, or bradyarrhythmias.

Twelve-lead ECG commonly shows a prolonged QT interval.

Sufferers are at increased risk of syncope, ventricular arrhythmias (including torsades de pointes), and sudden cardiac death.

Primary treatment involves beta-blockers and, in selected cases, implantation of a cardioverter-defibrillator, as well as avoidance of competitive sports and QT-prolonging drugs.

Long QT syndrome (LQTS) is a genetic or acquired condition characterised by a prolonged QT interval on the surface ECG and is associated with a high risk of sudden cardiac death due to ventricular tachyarrhythmias. Mutations within 13 identified genes result in a variety of channelopathies affecting myocardial repolarisation, thus prolonging the QT interval.