Torsades de pointes: Difference between revisions

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==Background==
==Background==
*Most commonly occurs in pts w/ prolonged QT due to heart diseaes or meds.
*Form of polymorphic [[VTach]]
**Procainamide
**Gradual change in the amplitude of QRS complexes and twisting around isoelectric line
**Phenothiazine
*Associated with congenital or acquired [[prolonged QT]]
**TCAs
**Qunidine
**Disopyramide


*'''POINTES''' mneumonic
===Common Causes===
**'''P'''henothiazines
'''POINTES''' mnemonic:
**'''O'''ther medications (tricyclic antidepressants)
*[[Phenothiazines|'''P'''henothiazines]]
**'''I'''ntracranial bleed
*'''O'''ther medications (ie [[TCAs]])
**'''N'''o known cause (idiopathic)
*[[ICH|'''I'''ntracranial bleed]]
**'''T'''ype I anti-arrhythmics (quinidine, procainamide, dispyramide)
*'''N'''o known cause (idiopathic)
**'''E'''lectrolyte abnormalities
*'''T'''ype I [[antiarrhythmics]] ([[quinidine]], [[procainamide]], disopyramide)
**'''S'''yndrome of Prolonged QT (aka Long QT Syndrome)
*[[electrolyte Abnormality|'''E'''lectrolyte abnormalities]] ([[hypokalemia|hypoK]] & [[hypomagnesemia|hypoMg]])
*'''S'''yndrome of [[Prolonged QT]] (aka Long QT Syndrome)
*Other causes:
**[[Organophosphate toxicity]]
**[[Hydrocarbon toxicity]]
**[[Chloral hydrate toxicity]]
**[[Hypothermia]]


==Treatment==
==Clinical Features==
*[[Syncope]]
*[[Dizziness]], lightheadedness
*[[Palpitations]]
*Sudden [[cardiac arrest]]
 
==Differential Diagnosis==
*Drug induced
*Congenital long QT
*[[Hypocalcemia]]
*[[Hypomagnesemia]]
*[[Hypokalemia]]
*[[Hypothermia]]
*POINTES as above
 
{{Tachycardia (wide) DDX}}
 
==Evaluation==
===Workup===
*[[ECG]]
*BMP, Mg, Phos
 
===Diagnosis===
[[File:12leadTorsade.jpg|thumb|Classic torsades in 12-lead]]
[[File:Torsades de Pointes TdP.png|thumb|Torsades de Pointes (TdP) in patient with a potassium of 2.4 mmol/L and a magnesium of 1.6mg/dL.]]
*[[ECG]] showing the QRS complexes “twisting” around the isoelectric line
 
==Management==
Increasing HR decreases QT interval
Increasing HR decreases QT interval
#Magnesium - decreases calcium influx
#[[Magnesium sulfate]] - decreases calcium influx
##1-2gm IV over 1-2 min, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) gtt
#*1-2gm IV over 1-2 min, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) drip
###Danger of hyperMag2+ → depressed neuromuscular function
#**Danger of [[hypermagnesemia]] → depressed neuromuscular function and respiratory drive, so monitor closely
###Supplement with K+
#**Supplement with K+
#Isoproterenol - Increases HR / AV conduction
#[[Isoproterenol]] - Increases HR / AV conduction
##2-8 mcg/min
#*2-8 mcg/min
#[[Overdrive Pacing]] - Atrial over ventricular pacing
#*Target HR > 90 bpm
##Goal HR 90-120
#[[Overdrive Pacing]] - Atrial > Ventricular pacing
#*Goal HR 90-120
#*Note: Not a treatment for TdP, but useful in maintaining sinus rhythm
#[[Defibrillation]] / [[synchronized cardioversion]] - Patient in extremis
#'''AVOID''' amiodarone and procainamide, which may worsen prolonged QT
# Lidocaine (a class Ib antiarrhythmic drug) shortens the QT interval and may be effective especially for drug-induced torsades de pointes.
 
==Disposition==
*Admit


==See Also==
==See Also==
Line 31: Line 69:
*[[ACLS (2010 Guidelines)]]
*[[ACLS (2010 Guidelines)]]


==Source ==
==References==
*Tintinalli
<references/>


[[Category:Cards]]
[[Category:Cardiology]]

Revision as of 18:31, 26 September 2019

Background

  • Form of polymorphic VTach
    • Gradual change in the amplitude of QRS complexes and twisting around isoelectric line
  • Associated with congenital or acquired prolonged QT

Common Causes

POINTES mnemonic:

Clinical Features

Differential Diagnosis

Wide-complex tachycardia

Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise (it is safer to incorrectly assume a ventricular dysrhythmia than supraventricular tachycardia with abberancy)

^Fixed or rate-related

Evaluation

Workup

  • ECG
  • BMP, Mg, Phos

Diagnosis

Classic torsades in 12-lead
Torsades de Pointes (TdP) in patient with a potassium of 2.4 mmol/L and a magnesium of 1.6mg/dL.
  • ECG showing the QRS complexes “twisting” around the isoelectric line

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) drip
      • Danger of hypermagnesemia → depressed neuromuscular function and respiratory drive, 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
    • Note: Not a treatment for TdP, but useful in maintaining sinus rhythm
  4. Defibrillation / synchronized cardioversion - Patient in extremis
  5. AVOID amiodarone and procainamide, which may worsen prolonged QT
  6. Lidocaine (a class Ib antiarrhythmic drug) shortens the QT interval and may be effective especially for drug-induced torsades de pointes.

Disposition

  • Admit

See Also

References