Polymorphic VT that develops in association with an acute coronary syndrome requires immediate DC cardioversion, as it frequently degenerates into ventricular fibrillation. Those patients with Torsades who are stable require intravenous magnesium and correction of underlying abnormalities (e.g. hypokalaemia, hypoxia) where appropriate [1].

Magnesium has diverse actions on the heart’s conduction system: it acts as an anti-arrhythmic agent and diminishes the frequency of ventricular ectopics. It is unlikely to be effective in polymorphic VT with a normal QT interval [4-5]. Overdrive pacing can be used as second-line therapy.