Adult Stable Polymorphic VT (Torsades de Pointes) is treated with which magnesium sulfate regimen?

Adult Stable Polymorphic VT (Torsades de Pointes) is treated with which magnesium sulfate regimen?

• A. Magnesium Sulfate: 2 g IV/IO in 100 mL bag, 10 DROP SET WIDE OPEN
• B. Magnesium Sulfate: 1 g IV in 50 mL bag
• C. Amiodarone: 150 mg IV
• D. Potassium chloride: 20 mEq IV

Answer: (A)

Torsades de pointes responds best to magnesium sulfate because magnesium helps stabilize the cardiac cell membranes and suppress the early afterdepolarizations that drive this arrhythmia. In an adult with stable polymorphic VT (torsades), giving magnesium quickly is the priority, even if serum magnesium isn’t demonstrably low. The recommended regimen is 2 g of magnesium sulfate given IV or IO in a 100 mL bag with a rapid infusion (wide-open drop set). This rapid delivery raises magnesium levels quickly to help terminate the rhythm and prevent recurrence. If needed, you can repeat the dose after several minutes and monitor the rhythm, airway, breathing, and circulation. Why the other options aren’t the best fit: a smaller, slower dose isn’t as effective for rapidly suppressing torsades; amiodarone is not the first choice for torsades and can worsen QT prolongation in this context; potassium chloride addresses potassium but doesn’t treat the underlying mechanism of torsades as effectively as magnesium does.

Torsades de pointes responds best to magnesium sulfate because magnesium helps stabilize the cardiac cell membranes and suppress the early afterdepolarizations that drive this arrhythmia. In an adult with stable polymorphic VT (torsades), giving magnesium quickly is the priority, even if serum magnesium isn’t demonstrably low.

The recommended regimen is 2 g of magnesium sulfate given IV or IO in a 100 mL bag with a rapid infusion (wide-open drop set). This rapid delivery raises magnesium levels quickly to help terminate the rhythm and prevent recurrence. If needed, you can repeat the dose after several minutes and monitor the rhythm, airway, breathing, and circulation.

Why the other options aren’t the best fit: a smaller, slower dose isn’t as effective for rapidly suppressing torsades; amiodarone is not the first choice for torsades and can worsen QT prolongation in this context; potassium chloride addresses potassium but doesn’t treat the underlying mechanism of torsades as effectively as magnesium does.