Difference between revisions of "Torsades de pointes"
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*Palpitations | *Palpitations | ||
*Sudden Cardiac Death | *Sudden Cardiac Death | ||
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| + | ==Differential Diagnosis== | ||
| + | *Drug induced | ||
| + | *Congenital long QT | ||
| + | *Hypocalcemia | ||
| + | *Hypomagnesemia | ||
| + | *Hypokalemia | ||
| + | *Hypothermia | ||
| + | *POINTES as above | ||
| + | |||
| + | {{Tachycardia (wide) DDX}} | ||
==Evaluation== | ==Evaluation== | ||
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[[File:12leadTorsade.jpg|thumb|Classic torsades in 12-lead]] | [[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.]] | [[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]] | + | *[[ECG]] showing the QRS complexes “twisting” around the isoelectric line |
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==Management== | ==Management== | ||
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#'''AVOID''' amiodarone and procainamide, which may worsen prolonged QT | #'''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. | # Lidocaine (a class Ib antiarrhythmic drug) shortens the QT interval and may be effective especially for drug-induced torsades de pointes. | ||
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| + | ==Disposition== | ||
| + | *Admit | ||
==See Also== | ==See Also== | ||
Revision as of 06:45, 5 April 2019
Contents
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:
- 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
- Dizziness
- Lightheadedness
- Palpitations
- Sudden Cardiac Death
Differential Diagnosis
- Drug induced
- Congenital long QT
- Hypocalcemia
- Hypomagnesemia
- Hypokalemia
- Hypothermia
- POINTES as above
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)
- Regular
- Monomorphic ventricular tachycardia
- PSVT with aberrant conduction:
- PSVT with bundle branch block^
- PSVT with accessory pathway
- Atrial flutter with bundle branch block^
- Sinus tachycardia with bundle branch block^
- Accelerated idioventricular rhythm (consider if less than or ~120 bpm)
- Metabolic
- Irregular
- Atrial fibrillation/atrial flutter with variable AV conduction AND bundle branch block^
- Atrial fibrillation/atrial flutter with variable AV conduction AND accessory pathway (e.g. WPW)
- Atrial fibrillation + hyperkalemia
- Polymorphic ventricular tachycardia
^Fixed or rate-related
Evaluation
Workup
- ECG
- BMP, Mg, Phos
Diagnosis
- ECG showing the QRS complexes “twisting” around the isoelectric line
Management
Increasing HR decreases QT interval
- 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+
- 1-2gm IV over 1-2 min, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) drip
- Isoproterenol - Increases HR / AV conduction
- 2-8 mcg/min
- Target HR > 90 bpm
- 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