What is the preferred pharmacologic agent for treating torsades de pointes with a pulse?

The preferred pharmacologic agent for treating torsades de pointes with a pulse is magnesium sulfate. This arrhythmia is often associated with a prolonged QT interval and can occur in the context of electrolyte imbalances, particularly low magnesium levels. Administering magnesium sulfate can help stabilize the myocardial cell membranes and restore a normal rhythm by addressing the underlying deficiency that may contribute to the arrhythmia.

Magnesium sulfate's effectiveness in acute situations is supported by clinical guidelines, which recommend it as the first-line treatment for torsades de pointes. When administered intravenously, a typical dose for this situation is 2 grams, which can rapidly correct magnesium levels and suppress the arrhythmia.

Other treatments listed, while used for different arrhythmias, are not the first choice for torsades de pointes. Amiodarone, for instance, is more suited for ventricular tachycardia or ventricular fibrillation due to its mechanism of action on sodium and potassium channels. Similarly, lidocaine is primarily effective for ventricular arrhythmias and may not effectively address the specific issues related to torsades de pointes. Procainamide, although it can be used for certain tachyarrhythmias, is not the recommended first-line choice for torsades given