Summary

• 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.