Difference between revisions of "Torsades de pointes"

(Text replacement - "==Source ==" to "==References== <references/>")
(Text replacement - "==Treatment==" to "==Management==")
Line 31: Line 31:
 
*POINTES as above
 
*POINTES as above
  
==Treatment==
+
==Management==
 
Increasing HR decreases QT interval
 
Increasing HR decreases QT interval
 
#[[Magnesium sulfate]] - decreases calcium influx
 
#[[Magnesium sulfate]] - decreases calcium influx

Revision as of 10:41, 9 July 2016

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

  • Syncope

Diagnosis

Classic torsades in 12-lead
12-lead ECG of Torsades de Pointes (TdP) in a 56-year-old white female with a potassium of 2.4 mmol/L and a magnesium of 1.6 mg/dL.
  • ECG
  • BMP, Mg, Phos

Differential Diagnosis

  • Drug induced
  • Congenital long QT
  • Hypocalcemia
  • Hypomagnesemia
  • Hypokalemia
  • Hypothermia
  • POINTES as above

Management

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
    • Target HR > 90 bpm
  3. Overdrive Pacing - Atrial > Ventricular pacing
    • Goal HR 90-120
  4. Defibrillation / synchronized cardioversion - Patient in extremis
  5. AVOID amiodarone and procainamide, which may worsen prolonged QT

See Also

References