Fatal arrhythmia is the leading cause of mortality in chronic haemodialysis patients. Long QT syndrome is responsible for polymorphic ventricular tachycardia known as Torsade de Pointes. Classically, long QT syndromes were divided into congenital and acquired; however ‘silent’ variants, in which patients remain asymptomatic until exposed to a drug or electrolyte disturbance precipitating the arrhythmia, have now been recognized.