Long QT syndrome refers to the prolongation of a patient's QT interval, at greater than 450 milliseconds for men and greater than 470 milliseconds for women. At intervals above 500 milliseconds, the risk of cardiac events is significantly multiplied as QTc prolongation predisposes individuals to ventricular tachyarrhythmias like TdP, ventricular fibrillation, and resulting death. LQTS may be inherited, or acquired due to drug effects or electrolyte changes.