Torsades de pointes

Background

• Torsades de Pointes is a form of polymorphic VTach, where there is a gradual change in the amplitude and twisting of the QRS complexes around the isoelectric line
• Associated with prolonged QT, which may be congenital or acquired. POINTES mnemonic for common etiologies:
  • Phenothiazines
  • Other medications (ie TCAs)
  • Intracranial bleed
  • No known cause (idiopathic)
  • Type I anti-arrhythmics (quinidine, procainamide, disopyramide)
  • Electrolyte abnormalities (hypoK & hypoMag)
  • Syndrome of Prolonged QT (aka Long QT Syndrome)

Treatment

Increasing HR decreases QT interval

1. Magnesium - decreases calcium influx
   • 1-2gm IV over 1-2 min, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) gtt
     • Danger of hyperMag2+ → depressed neuromuscular function, so monitor closely
     • Supplement with K+
2. Isoproterenol - Increases HR / AV conduction
   • 2-8 mcg/min
3. Overdrive Pacing - Atrial > Ventricular pacing
   • Goal HR 90-120
4. Defibrillation / Synchronized Cardioversion - Patient in extremis

See Also

• Tachycardia (Wide)
• ACLS (2010 Guidelines)

Source

• Tintinalli