The QT interval is the time from the beginning of the QRS complex, representing ventricular depolarization, to the end of the T wave, resulting from ventricular repolarization. The normal QT ...

A prolonged QT interval has a variety of causes and can be a very serious ECG finding, as it may lead to the potentially fatal arrhythmia polymorphic ventricular tachycardia (Torsades de Pointes).

Long QT syndrome (LQTS) is potentially lethal if left untreated. Accurate diagnosis is, therefore, vital. Patients with LQTS have impaired adaptation of the QT interval in response to changes in ...