Which statement correctly describes the use of magnesium in torsades de pointes?

• A. Magnesium sulfate is given intravenously; underlying causes are corrected and patient monitored
• B. Magnesium is avoided due to pro-arrhythmic risk
• C. Only potassium is addressed; magnesium is not used
• D. Magnesium is given orally

Answer: (A)

In torsades de pointes, the immediate goal is to suppress the abnormal stopped-to-start oscillation of the ventricles and prevent recurrence. Magnesium sulfate given intravenously is the first-line treatment because it helps stabilize the cardiac membranes and reduces early afterdepolarizations that drive this arrhythmia. This effect is useful even if the patient’s magnesium level is not low, which is why IV magnesium is used rather than relying on oral supplements.

Beyond giving magnesium, the underlying triggers must be addressed: correct electrolyte disturbances such as low potassium or low magnesium, discontinue or avoid QT-prolonging drugs, and manage bradycardia if present (sometimes with pacing or drugs that increase heart rate). The patient is then closely monitored with continuous ECG and clinical observation to ensure the rhythm stabilizes and to catch any recurrence.

Oral magnesium isn’t appropriate in this acute setting because it acts too slowly. Magnesium is not avoided due to pro-arrhythmic risk; it’s specifically used to counteract the arrhythmia.