Polymorphic ventricular tachycardia

• Myocardial ischemia (most common)
• Acquired or congenital prolonged QT
  • TCAs, phenothiazines, Type I antiarrhythmics (quinidine, procainamide)
  • Hypokalemia
  • Hypomagnesemia
  • Elevated intracranial pressure
• Brugada syndrome, short QT syndrome, congenital catecholaminergic polymorphic ventricular 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
    • Hyperkalemia
    • Digoxin toxicity
    • Severe metabolic acidosis
• 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
    • Torsades de pointes
    • Nonsustained ventricular tachycardia

^Fixed or rate-related

• 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

See Adult pulseless arrest and Pediatric pulseless arrest

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

• 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
  • Sotalol (100mg IV over 5 minutes)
  • Isoproterenol, 2-8 mcg/min
  • 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
  • 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

• ≥3 episodes within 24 hours considered electrical storm
• May require alternate treatment (i.e. β-blockers, sedation, ablation)