Polymorphic ventricular tachycardia: Difference between revisions
 
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==Background==
==Background==
*Form of [[ventricular tachycardia]] in which there are multiple ventricular foci, leading to QRS complexes with varying morphology
*Form of [[ventricular tachycardia]]
*Subtypes include [[Torsades de pointes]], bidirectional polymorphic VTach (seen in [[digoxin toxicity]]
**Multiple ventricular foci
**QRS complexes with varying morphology
*Subtypes include:
**[[Torsades de pointes]]
**bidirectional polymorphic [[VTach]] (as seen in [[digoxin toxicity]])


===Etiologies===
===Etiologies===
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*[[Syncope]]
*[[Syncope]]
*[[Palpitations]]
*[[Palpitations]]
*[[Altered level of consciousness]]
*May present with [[cardiac arrest]]


==Differential Diagnosis==
==Differential Diagnosis==
''Assume any wide-complex tachycardia is [[ventricular tachycardia]] until proven otherwise''
{{Tachycardia (wide) DDX}}
*[[A-fib]]/[[flutter]] with variable AV conduction AND bundle branch block (fixed or rate-related)
*A-fib/flutter with variable AV conduction AND accessory pathway (e.g. [[WPW]])
*A-fib + [[hyperkalemia]]


==Evaluation==
==Evaluation==
[[File:Torsades de Pointes (polymorphic VT).svg|thumb|Torsades de Pointes in a rhythm strip.]]
*Evaluate for underlying causes (e.g. electrolyte imbalances, [[ACS]])
*Evaluate for underlying causes (e.g. electrolyte imbalances, [[ACS]])


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*Wide QRS (>100ms or 3 small boxes)
*Wide QRS (>100ms or 3 small boxes)
*QRS complexes of varied amplitude, axis and duration
*QRS complexes of varied amplitude, axis and duration
***Torsades: QRS complexes appear to twist around isoelectric line
**Torsades: QRS complexes appear to twist around isoelectric line
*Rapid rhythm (usually 140-160 bpm, but can be up to 300 bpm)
*Rapid rhythm (usually 140-160 bpm, but can be up to 300 bpm)
*Irregular
*Irregular
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===Stable===
===Stable===
*Correct any electrolyte abnormalities
*Correct any electrolyte abnormalities
*Torsades:
*[[Torsades]]:
**[[Magnesium]] sulfate (for Torsades):  
**[[Magnesium]] sulfate (for Torsades):  
***1-2gm IV, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) drip
***1-2gm IV, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) drip
***Peds: 25-50mg/kg (max 2g) IV
***Peds: 25-50mg/kg (max 2g) IV
**[[Sotalol]] (100mg IV over 5 minutes)
**[[Isoproterenol]], 2-8 mcg/min (if available)
**[[Isoproterenol]], 2-8 mcg/min
**[[Overdrive Pacing]] to goal HR 90-120
**[[Overdrive Pacing]] to goal HR 90-120  
***Note that this is only effective for preventing recurrence of TdP - it will not convert TdP to sinus rhythm
**Consider Lidocaine
**Avoid procainamide, amiodarone (may further prolong QT)
**Avoid procainamide, amiodarone (may further prolong QT)
*Non-Torsades
*Non-Torsades (baseline QT interval not prolonged)
**[[Amiodarone]], agent of choice in setting of AMI or LV dysfunction
**[[Amiodarone]], agent of choice in setting of AMI or LV dysfunction
***150 mg over 10min (15 mg/min), followed by 1 mg/min drip over 6hrs (360 mg total), then 0.5 mg/min drip over next 18 hrs (540 mg total)
***150 mg over 10min (15 mg/min), followed by 1 mg/min drip over 6hrs (360 mg total), then 0.5 mg/min drip over next 18 hrs (540 mg total)
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**[[Procainamide]]
**[[Procainamide]]
***100 mg q5min until termination of arrhythmia, then start 2-6 mg/min (or 1-2 mg/min for renal/cardiac failure)  
***100 mg q5min until termination of arrhythmia, then start 2-6 mg/min (or 1-2 mg/min for renal/cardiac failure)  
***Max dose 17mg/kg OR widening of QRS >50%
***Max dose 17mg/kg '''OR''' widening of QRS >50%
**[[Lidocaine]], 1-1.5mg/kg IV q5min, repeat prn up to 300mg/hr
**[[Lidocaine]], 1-1.5mg/kg IV q5min, repeat PRN up to 300mg/hr
**[[Beta-blockers]] (e.g. [[metoprolol]] 5mg IV q5m x 3) if blood pressure tolerates


===Refractory===
===Refractory===
*≥3 episodes within 24 hours considered [[electrical storm]]
*≥3 episodes within 24 hours considered [[electrical storm]]
*May require alternate treatment (i.e. [[beta blockers]], sedation, ablation)
*May require alternate treatment (i.e. [[β-blockers]], sedation, ablation)


==Disposition==
==Disposition==
*Admit, even if back in normal sinus rhythm
*Admit with cardiology consult, even if back in normal sinus rhythm
**Stable patients may be admitted to ward
***Pads should remain on patient's chest anticipating need for repeat cardioversion
***All patients should remain on telemetry or full cardio-respiratory monitoring for recurrent events
**Patients with features of instability or refractory VT are best admitted to CCU or ICU and may require urgent or emergent pacemaker placement


==See Also==
==See Also==

Latest revision as of 16:50, 30 July 2025

Background

Etiologies

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

Torsades de Pointes in a rhythm strip.
  • Evaluate for underlying causes (e.g. electrolyte imbalances, ACS)

ECG Findings

  • Wide QRS (>100ms or 3 small boxes)
  • QRS complexes of varied amplitude, axis and duration
    • Torsades: QRS complexes appear to twist around isoelectric line
  • Rapid rhythm (usually 140-160 bpm, but can be up to 300 bpm)
  • Irregular

Management

Pulseless

See Adult pulseless arrest and Pediatric pulseless arrest

Unstable

  • Unsynchronized cardioversion (defibrillation) 200J (or 2J/kg for pediatrics)
  • Correct any electrolyte abnormalities

Stable

  • Correct any electrolyte abnormalities
  • Torsades:
    • Magnesium sulfate (for Torsades):
      • 1-2gm IV, repeat in 5-15min; then 1-2gm/hr (3-10mg/min) drip
      • Peds: 25-50mg/kg (max 2g) IV
    • Isoproterenol, 2-8 mcg/min (if available)
    • Overdrive Pacing to goal HR 90-120
      • Note that this is only effective for preventing recurrence of TdP - it will not convert TdP to sinus rhythm
    • Consider Lidocaine
    • Avoid procainamide, amiodarone (may further prolong QT)
  • Non-Torsades (baseline QT interval not prolonged)
    • Amiodarone, agent of choice in setting of AMI or LV dysfunction
      • 150 mg over 10min (15 mg/min), followed by 1 mg/min drip over 6hrs (360 mg total), then 0.5 mg/min drip over next 18 hrs (540 mg total)
      • Peds: 5mg/kg (max 300mg), may repeat twice
    • Procainamide
      • 100 mg q5min until termination of arrhythmia, then start 2-6 mg/min (or 1-2 mg/min for renal/cardiac failure)
      • Max dose 17mg/kg OR widening of QRS >50%
    • Lidocaine, 1-1.5mg/kg IV q5min, repeat PRN up to 300mg/hr
    • Beta-blockers (e.g. metoprolol 5mg IV q5m x 3) if blood pressure tolerates

Refractory

Disposition

  • Admit with cardiology consult, even if back in normal sinus rhythm
    • Stable patients may be admitted to ward
      • Pads should remain on patient's chest anticipating need for repeat cardioversion
      • All patients should remain on telemetry or full cardio-respiratory monitoring for recurrent events
    • Patients with features of instability or refractory VT are best admitted to CCU or ICU and may require urgent or emergent pacemaker placement

See Also

External Links

References

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