What is the treatment for torsades de pointes?

Treatment for Torsades de Pointes

Administer intravenous magnesium sulfate 1-2 g over 1-2 minutes immediately as first-line therapy, even when serum magnesium levels are normal, as this is the treatment of choice for torsades de pointes. 1, 2

Immediate Stabilization

Hemodynamic Assessment

• Perform immediate direct current cardioversion with appropriate sedation if the patient is hemodynamically unstable 1, 2
• Withdraw all QT-prolonging medications immediately 1, 2

First-Line Pharmacologic Therapy

• Administer IV magnesium sulfate 1-2 g over 1-2 minutes as initial therapy, which is effective even with normal serum magnesium levels 1, 2, 3
• In pediatric patients, give 25-50 mg/kg IV (maximum 2 g): as a bolus for pulseless torsades or over 10-20 minutes for torsades with pulses 1
• Monitor for hypotension and bradycardia during rapid infusion, and have calcium chloride available to reverse potential magnesium toxicity 1

Electrolyte Correction

• Target serum potassium between 4.5-5 mEq/L to shorten the QT interval and reduce recurrence 1, 2
• Correct hypomagnesemia aggressively 1

Second-Line Interventions (When Magnesium Fails)

Cardiac Pacing

• Temporary cardiac pacing is highly effective for recurrent torsades after magnesium and potassium supplementation 1, 2
• Pacing shortens the QT interval and eliminates the pauses that precipitate torsades 4

Isoproterenol Infusion

• Start isoproterenol at 2-10 mcg/min IV infusion when temporary pacing cannot be immediately implemented 2
• Titrate to increase heart rate sufficiently to abolish postectopic pauses 2
• Critical contraindication: Avoid isoproterenol in patients with congenital long QT syndrome, as it can worsen the condition 2, 4
• Only use isoproterenol for pause-dependent torsades in acquired LQTS when the underlying rhythm is slow 2, 4
• Monitor for hypotension and myocardial ischemia 2
• Continue until the underlying cause is corrected 2

Special Clinical Situations

Ischemia-Associated Torsades

• Perform urgent coronary angiography with view to revascularization 1
• Administer intravenous beta blockers 1

LQT3 Patients

• Consider intravenous lidocaine or oral mexiletine 1

Digoxin-Induced Torsades

• Administer digoxin-specific Fab antibody for severe intoxication 1

Critical Pitfalls to Avoid

• Do not use standard antiarrhythmic drugs (particularly Class IA agents like quinidine or disopyramide), as they prolong the QT interval and will aggravate torsades 5
• Recognize that sodium channel blockers can increase defibrillation energy requirements and pacing thresholds, potentially requiring cardiac device reprogramming 1
• Be aware that continuous maternal administration of magnesium sulfate beyond 5-7 days in pregnancy can cause fetal abnormalities 3
• In severe renal insufficiency, do not exceed 20 grams magnesium sulfate per 48 hours and obtain frequent serum magnesium concentrations 3
• Watch for "impending torsades" signs: bizarre QT changes with giant U waves in the sinus complex following postextrasystolic pauses 4