Torsades de Pointes may benefit from administration of which medication?

• A. Lidocaine
• B. Magnesium sulfate
• C. Amiodarone
• D. Adenosine

Answer: (B)

Torsades de Pointes is driven by prolonged repolarization and early afterdepolarizations, so treatment focuses on stabilizing the myocardium and stopping those afterdepolarizations. Magnesium sulfate is the best choice because it helps regulate calcium influx during the plateau phase, suppresses early afterdepolarizations, and stabilizes the cardiac membrane, which reduces the tendency for this polymorphic VT to develop. It’s effective even when magnesium levels are normal, making it the go-to therapy in this scenario.

Other options don’t address the underlying mechanism. Lidocaine targets certain ventricular arrhythmias but not the prolonged QT–driven torsades. Amiodarone can prolong the QT interval and isn’t the preferred remedy for torsades. Adenosine is used for certain supraventricular tachycardias and has no role here.