Which of the following is the treatment of choice for torsades de pointes?

Occasional patients will have recurrent episodes of torsade (“Torsade storm”).  Each individual episode may be treated with magnesium or defibrillation, if needed (Treatment step #1 above).  However, additional therapies are required to stop recurrence and end the storm.

re-load magnesium if needed

• Recurrent torsade may reflects inadequate magnesium dosing (e.g., patient is bolused with 2-4 grams, without an infusion).  The first step when managing recurrent torsade is therefore to ensure that the patient has truly received an adequate dose of magnesium.
• If the patient was bolused with magnesium a few hours ago without an infusion, re-load with 2-4 grams IV immediately (8-16 mM).
• If the patient is a candidate for magnesium infusion (GFR >30 ml/hr), this should be started.
• If the patient has renal failure and has already received 4-6 grams of magnesium (16-24 mM), then check magnesium levels and ensure that a high level is achieved.   Note that a therapeutic level for torsade is roughly 3.5-5 mg/dL (1.5-2 mM) – not a “normal” level.
• More on magnesium above.📖

treat any other precipitating factors

• Hypokalemia, should be treated aggressively, targeting a high-normal potassium level (>4.5 mEq/L).(29084733)
• Hypocalcemia may promote torsade and should be treated if present.📖
• Hypothermia should be aggressively reversed.📖

speed up the heart

• Speeding up the heart rate will generally decrease the QT interval and reduce the risk of acquired torsade.  However, this probably doesn't work in Type-I congenital long-QT syndrome, which is not a pause-dependent arrhythmia. 📄 (34039680)  
• The usefulness of chronotropy depends on the patient's baseline heart rate.
  • Chronotropy is most beneficial for patients starting out with bradycardia.
  • If the patient is already significantly tachycardic, chronotropy is unlikely to provide benefit.  The usual target heart rate is 100-110 b/m, but occasionally heart rates up to 140 b/m may be needed.(26183037)  There's no high-quality data on this.
• Medical chronotropy is generally the easiest & fastest way to stabilize the patient.  The ideal chronotrope depends on the patient's hemodynamics and baseline blood pressure.
  • Baseline severe hypotension:  epinephrine infusion.
  • Baseline normotension or mild hypotension:  dobutamine or isoproterenol infusion.
  • ⚠️ Caution:  If chronotropic therapy causes lots of premature ventricular complexes, this may be counterproductive (since premature ventricular complexes can trigger torsade).(31114687)  In this situation, consider transvenous pacing and/or lidocaine.
  • ⚠️ Caution:  Beta-adrenergic agonists are contraindicated in patients with congenital long-QT syndrome.
• Electrical chronotropy may be used if medical chronotropy fails or is contraindicated:
  • Transcutaneous pacing may work, but this is painful for conscious patients.
  • Transvenous pacing is more comfortable, but this is more invasive and takes a bit longer to achieve.
  • Patients with a pacemaker may have the device rate increased.

lidocaine 💊

• Lidocaine is the preferred antiarrhythmic drug for torsade, although there isn't a ton of evidence supporting its use.
  • Do not use amiodarone, procainamide, beta-blockers, or most other antiarrhythmics.  Most of these will stretch out the QT interval even further!  Beta-blockers will slow down the heart rate, increasing the risk of torsade (although beta-blockers may be beneficial in some patients with congenital long-QT syndrome).📄 (34039680) 
• Start with a loading dose of 1-1.5 mg/kg lidocaine followed by a 1 mg/min infusion.  For recurrent arrhythmias, re-load with another 1 mg/kg bolus and increase the maintenance infusion to 2-3 mg/min.

consider an alternative diagnosis

• Acquired torsade is generally fairly easy to control with a combination of high-dose magnesium, heart rate augmentation, and occasionally some lidocaine.  Failure to respond to these interventions suggests an alternative diagnosis (e.g. polymorphic VT due to ischemia, catecholaminergic ventricular tachycardia, or congenital long-QT syndrome).

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What is the best treatment for torsades de pointes?

How is torsades treated?

Which of the following is not a treatment for torsades de pointes?

Does amiodarone treat torsades de pointes?