Which electrolyte imbalance is seen with torsades de pointes?

Which electrolyte imbalance is seen with torsades de pointes?

• A. Hypermagnesemia
• B. Hypokalemia
• C. Hyperkalemia
• D. Hypomagnesemia

Answer: (D)

Low magnesium levels are a classic trigger for torsades de pointes. Torsades is a polymorphic ventricular tachycardia that arises when the heart’s repolarization is prolonged, creating early afterdepolarizations that can spark this dangerous rhythm. Magnesium helps stabilize the cardiac membrane and modulate calcium and potassium channel activity, reducing these afterdepolarizations. That’s why IV magnesium sulfate is the recommended first-line treatment for torsades, even if magnesium levels aren’t severely low. Hypokalemia can also contribute to QT prolongation and torsades, but the specific electrolyte imbalance most closely linked with this arrhythmia is low magnesium. Hypermagnesemia and hyperkalemia have different effects on conduction and rhythm and are not the typical culprits for torsades.

Low magnesium levels are a classic trigger for torsades de pointes. Torsades is a polymorphic ventricular tachycardia that arises when the heart’s repolarization is prolonged, creating early afterdepolarizations that can spark this dangerous rhythm. Magnesium helps stabilize the cardiac membrane and modulate calcium and potassium channel activity, reducing these afterdepolarizations. That’s why IV magnesium sulfate is the recommended first-line treatment for torsades, even if magnesium levels aren’t severely low.

Hypokalemia can also contribute to QT prolongation and torsades, but the specific electrolyte imbalance most closely linked with this arrhythmia is low magnesium. Hypermagnesemia and hyperkalemia have different effects on conduction and rhythm and are not the typical culprits for torsades.