II. Indications: Wide Complex Tachycardia in Adults

  1. Tachycardia (Heart Rate >130, and typically >150 bpm) AND
  2. Wide QRS Complex (duration at least 0.12 sec)
  3. No P Wave to QRS Complex relationship (other than retrograde P Waves)

III. Precautions: SVT with aberrancy

  1. Manage Wide Complex Tachycardia as Ventricular Tachycardia
  2. Algorithms (e.g. Griffith, Brugada, Bayesian) are inadequate
    1. Cannot distinguish VT from SVT with aberrancy (or RBBB) - miss rates of 6-7% at best
    2. Jastrezbski (2012) Europace 14(8): 1165-71 [PubMed]
    3. Szelenyi (2013) Acad Emerg Med 20(11): 1121-30 [PubMed]
  3. Consequence of treating Ventricular Tachycardia as SVT (e.g. with Calcium Channel Blocker) can be lethal
    1. In contrast, treating SVT with aberrancy with an Antiarrhythmic (e.g. Procainamide) is unlikely to cause harm
  4. Adenosine use in Wide Complex Tachycardia is also controversial
    1. Ventricular Tachycardia will convert to sinus rhythm with Adenosine in 5-10% of cases
    2. Conversion with Adenosine leads to incorrect conclusion that the underlying rhythm was SVT with aberrancy
    3. May result in missed VT diagnosis
      1. Misses associated telemetry admission, Antiarrhythmics and electrophysiology evaluation
    4. Amal Mattu recommends not using Adenosine in Wide Complex Tachycardia
      1. Risk of masking potentially lethal VT in up to 10% of cases
  5. References
    1. Mattu in Herbert (2014) EM:Rap 14(7): 4-5, 13-14

IV. Approach: General

  1. ABC Management with IV-O2-Monitor is paramount in all cases
  2. No pulse
    1. Treat as Pulseless Ventricular Tachycardia
  3. Unstable (Hypotension, ALOC, ischemic Chest Pain or acute CHF)
    1. Treat as Unstable Ventricular Tachycardia
    2. Administer Synchronized Cardioversion
  4. Stable
    1. Assess QRS Complex morphology
    2. Treat per protocols below
      1. Monomorphic Ventricular Tachycardia
      2. Polymorphic Ventricular Tachycardia

V. Approach: Wide Complex Tachycardia (key question is 'regular or irregular')

  1. Unstable Wide Complex Tachycardia
    1. Synchronized Cardioversion (or asynchronized, Defibrillation if not responding)
  2. Stable Wide Complex Tachycardia (see each approach described in sections below)
    1. Irregular Wide Complex Tachycardia
    2. Regular Wide Complex Tachycardia

VI. Approach: Irregular Wide Complex Tachycardia (stable)

  1. Polymorphic Ventricular Tachycardia
    1. INITIAL Steps
      1. Immediate Defibrillation (non-Synchronized Cardioversion)
      2. Differentiation based on QT Interval is directed at prevention of recurrent Arrhythmia
    2. Prolonged QT interval (on baseline EKG): Torsades de Pointes
      1. Give Magnesium 2 grams IV
        1. May be repeated in 5-15 minutes
        2. May be continued as infusion Magnesium 3 to 20 mg/min IV for Prolonged QTc
      2. Correct other Electrolyte abnormalities (5H5T)
      3. Stop all medications that prolong QT Interval
        1. Do NOT give any AV Nodal blocking agents (e.g. Amiodarone, Beta Blockers, Calcium Channel Blockers)
        2. Do NOT give any agent that prolongs QTc (e.g. Procainamide)
      4. Reverse toxic ingestions and Poisonings
      5. Consider overdrive pacing to Heart Rate of 100 bpm
      6. Avoid Isoproterenol (used historically)
    3. Normal QT Interval (on baseline EKG): Polymorphic Ventricular Tachycardia
      1. Exercise caution that QTc is normal (not Torsades de Pointes)
        1. All agents described below can be lethal in Torsades de Pointes
        2. If in doubt, treat as Torsades de Pointes (esp. Magnesium)
      2. Myocardial Ischemia (most common)
        1. Beta Blockers
        2. Emergent cardiac catheterization for revascularization
        3. Consider Amiodarone 150 mg IV
      3. Catecholaminergic Ventricular Tachycardia
        1. Consider Beta Blockers
      4. Brugada Syndrome
        1. Consider Isoproterenol
  2. Pre-excited Atrial Fibrillation (antegrade conduction via accessory pathway, e.g. WPW)
    1. Rhythm is more irregular (R-R Interval) than with Polymorphic Ventricular Tachycardia (Torsades de Pointes)
    2. Avoid AV Nodal blockers (Beta Blockers, Diltiazem, Verapamil, Digoxin, Adenosine)
    3. Consult with local experts
    4. Rapid Heart Rate typically requires electrical cardioversion
    5. Consider Amiodarone 150 mg IV
  3. Atrial Fibrillation with aberrancy
    1. Treat as Narrow Complex Tachycardia only if can rule-out pre-excited Atrial Fibrillation

VII. Approach: Regular Wide Complex Tachycardia (stable)

  1. INITIAL: Adenosine (or go to below under Ventricular Tachycardia)
    1. AVOID if polymorphic or irregular Wide Complex Tachycardia (can degenerate to VF)
      1. Some experts recommend avoiding Adenosine in all cases of Ventricular Tachycardia (see precautions above)
    2. Dose: 6 mg IV (may repeat with up to two 12 mg IV doses)
    3. Effect
      1. SVT (or aberrancy): converts or at least slows rhythm for interpretation
      2. VT: no effect
        1. Exception: Irregular (in which case could degenerate into VF)
        2. Exception: 10% of Ventricular Tachycardia converts with Adenosine
          1. Response to Adenosine does NOT rule out Ventricular Tachycardia
  2. Monomorphic Ventricular Tachycardia (assume until proven otherwise)
    1. Synchronized Cardioversion if unstable or refractory to measures below
    2. Recommended agents for chemical cardioversion
      1. Procainamide
        1. Preferred if not contraindicated
          1. Zipes (2006) Circulation 114(10): e385-484 [PubMed]
        2. AVOID in Prolonged QT or CHF
        3. Loading Dose 50 mg/min
          1. Target: Until successful, Hypotension, or QRS widens >50%
          2. May slow rate to 20 mg/min (or stop and restart slowly) if QRS Widening or QT Prolongation occurs during infusion
          3. Maximum: Cummulative dose 17 mg/kg (or ~1 gram)
        4. Maintenance: 1-4 mg/min
          1. Post-cardioversion Antiarrhythmic infusion may be replaced with Beta Blocker instead (see below)
      2. Amiodarone
        1. Preferred in CHF or Prolonged QT (but effective in only 20% of cases)
        2. Dose 150 mg IV over 10 minutes
        3. Maintenance: 1 mg/min for 6 hours
          1. Post-cardioversion Antiarrhythmic infusion may be replaced with Beta Blocker instead (see below)
      3. Sotalol
        1. AVOID in Prolonged QT
        2. Dose 1.5 mg/kg up to 100 mg over 5 minutes
    3. Post-Cardioversion (chemical or electrical) management
      1. Beta Blocker (Metoprolol or Esmolol)
        1. Consider starting after successful cardioversion (not before due to negative inotropy)
        2. Suppresses Ventricular Tachycardia associated Catecholamine surges
        3. Consider in place of Antiarrhythmic infusions listed above

VIII. Management: Pregnancy

  1. Monitor both mother and fetus
  2. Women in pregnancy are more prone to supraventricular and ventricular Arrhythmias
    1. Increased Heart Rate, decreased Peripheral Vascular Resistance, increased Stroke Volume
  3. Evaluate for preexcitation syndromes (e.g. WPW)
    1. As in non-pregnant patients, avoid all AV Nodal blocking agents (e.g. Adenosine, Calcium Channel Blockers, Beta Blockers)
  4. Safe measures
    1. Procainamide
      1. Safe and well tolerated in pregnancy
    2. Cardioversion
      1. Avoid placing cardioversion pads over the Abdomen (place in typical chest positions)
      2. Minimal electrical penetration into Uterus
    3. Sedation
      1. Aspiration risk
      2. Avoid Hypotension
      3. Preferred sedation with Propofol or Ketamine
  5. Medications to avoid
    1. Amiodarone
      1. Risk of exposing fetal Thyroid to high Iodine
      2. Risk of IUGR
      3. Risk of Preterm Labor
  6. References
    1. DeMeester and Cormack in Herbert (2021) EM:Rap 21(9): 10-2

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