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.📖
- 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.📖
- 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 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.
- 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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questions & discussion
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To keep this page small and fast, questions & discussion about this post can be found on another page here.
What is the best treatment for torsades de pointes?
Intravenous magnesium is the first-line pharmacologic therapy in Torsades de Pointes. Magnesium has been shown to stabilize the cardiac membrane, though the exact mechanism is unknown. The recommended initial dose of magnesium is a slow 2 g IV push.
How is torsades treated?
The torsades rhythm is treated with magnesium sulfate 2 g IV over 1 to 2 minutes, correction of hypokalemia, pacing or isoproterenol to increase heart rate, and correction of the cause.
Which of the following is not a treatment for torsades de pointes?
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].
Does amiodarone treat torsades de pointes?
Background Amiodarone is an effective antiarrhythmic drug rarely associated with torsade de pointes arrhythmias [TdP]. The noniodinated compound dronedarone could resemble amiodarone and be devoid of the adverse effects.