Torsades de pointes

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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.

Common Causes

POINTES mnemonic:

    • 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)

Clinical Features

Diagnosis

Torsades in 12-lead
  • [[ECG]

Differential Diagnosis

Treatment

Increasing HR decreases QT interval

  1. Magnesium sulfate - decreases calcium influx
    • 1-2gm IV over 1-2 min, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) gtt
      • Danger of hypermagnesemia → 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

Source