First-line treatment for torsades de pointes is which therapy?

• A. Lidocaine
• B. Amiodarone
• C. Calcium Gluconate
• D. Magnesium Sulfate

Answer: (D)

Torsades de pointes is a dangerous form of polymorphic ventricular tachycardia driven by prolonged QT and early afterdepolarizations. The first-line therapy is intravenous magnesium sulfate because it directly suppresses those abnormal depolarizations and stabilizes the cardiac membrane, reducing the likelihood of recurrence even if serum magnesium is not low. Typical management involves giving magnesium sulfate as a bolus (about 1–2 g IV, may be repeated) and then continuing with a magnesium infusion as needed, all while correcting electrolytes and monitoring the rhythm.

Lidocaine and amiodarone are not preferred for torsades because they do not address the underlying QT-related triggers and can sometimes worsen the situation by prolonging QT. Calcium gluconate is useful if there is true hypocalcemia, but it does not prevent early afterdepolarizations in the same way magnesium does, so it isn’t the first choice for torsades.