Long QT syndrome (LQTS) is an inherited condition associated with delayed repolarization of the ventricles. It is important to recognise as it may lead to ventricular tachycardia/torsade de pointes and can therefore cause collapse/sudden death. The most common variants of LQTS (LQT1 & LQT2) are caused by defects in the alpha subunit of the slow delayed rectifier potassium channel. A normal corrected QT interval is less than 430 ms in males and 450 ms in females.

Causes:

Features

• may be picked up on routine ECG or following family screening
• Long QT1 - usually associated with exertional syncope, often swimming
• Long QT2 - often associated with syncope occurring following emotional stress, exercise or auditory stimuli
• Long QT3 - events often occur at night or at rest
• sudden cardiac death

Management

• Beta blockade
• Cardiac Pacing
• Manage underlying cause
• Implantation of ICD