Wide complex tachycardia

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  • 3 wide complexes in a row is considered ventricular tachycardia; non-sustained if lasts less than 30 seconds
  • Sustained ventricular tachycardia is ventricular tachycardia >30 seconds


  • WCT is due to true ventricular tachycardia in 80% of cases
  • For patients with underlying cardiac disease, this number increases to > 90%
  • Multiple other causes must be considered, including Hyperkalemia, Digoxin toxicity, severe metabolic acidosis, and others

Clinical Features

Differential Diagnosis



  • A-fib/flutter with variable AV conduction AND BBB (fixed or rate-related)
  • A-fib/flutter with variable AV conduction AND accessory pathway (eg WPW)
  • A-fib + Hyperkalemia
  • Polymorphic v-tach/torsades


Ventricular tachycardia


Wide Regular Tachycardia[4]

Pulseless: see Adult pulseless arrest

  • Unstable: Hypotension, altered mental status, shock, ischemic chest discomfort, acute heart failure
  • Stable:
    1. Medications
      • Procainamide (first-line drug of choice)
        • 20-50mg/min until arrhythmia suppressed (max 17mg/kg or 1 gram); then, maintenance infusion of 1-4mg/min x 6hr
          • Alternative administration: 100 mg q5min at max rate of 25-50 mg/min[5]
        • Stop if QRS duration increases >50% or hypotension
        • Avoid if prolonged QT or CHF
        • Favored over Amiodarone in PROCAMIO trial; termination of tachycardia in 67% of procainamide group vs 38% of amiodarone group, adverse cardiac events 9% vs 41%, respectively [6]
      • 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)[7]
        • Then 0.5 mg/min drip over next 18 hrs (540 mg total)
        • Oral dosage after IV infusion is 400 -800 mg PO daily
      • Consider adenosine
    2. Synchronized Cardioversion (100J)

Wide Irregular Tachycardia

DO NOT use AV nodal blockers as they can precipitate V-Fib
Pulseless: see Adult pulseless arrest


  • ≥3 episodes within 24 hours considered electrical storm and may require alternate treatment (i.e. beta blockade, sedation, ablation)

Other considerations

  • True Vtach generally has rate >120bpm. If rate <120bpm or refractory to other therapy, consider other causes
  • When in doubt, use cardioversion for treatment of regular WCT. In irregular WCT, consider Afib with WPW in which Procainamide is the treatment of choice.
  • In very wide complex (>0.2 msec) and <120 bpm in a patient with significant history, consider giving calcium chloride to treat hyperkalemia
  • Consider Acidosis
  • Sodium channel blockade (e.g. from benadryl, TCA, or cocaine toxicity) may cause very wide complex (>0.2msec) tachycardia with rate <120bpm


  • Admit all patients (even if converted to normal sinus rhythm in ED)

See Also



  1. Gupta AK, Thakur RK. Wide QRS complex tachycardias. Med Clin North Am. 2001;85(2):245–66– ix–x.
  2. Akhtar M, Shenasa M, Jazayeri M, Caceres J, Tchou PJ. Wide QRS complex tachycardia. Reappraisal of a common clinical problem. Ann Intern Med. 1988;109(11):905–912.
  3. Stewart RB, Bardy GH, Greene HL. Wide complex tachycardia: misdiagnosis and outcome after emergent therapy. Ann Intern Med. 1986;104(6):766–771.
  4. American Heart Association. Web-based Integrated Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care – Part 7: Adult Advanced Cardiovascular Life Support. ECCguidelines.heart.org
  5. Procainamide. GlobalRPH. http://www.globalrph.com/procainamide_dilution.htm.
  6. Ortiz M, Martín A, Arribas F, et al. Randomized comparison of intravenous procainamide vs. intravenous amiodarone for the acute treatment of tolerated wide QRS tachycardia: the PROCAMIO study. Eur Heart J. 2017 May 1;38(17):1329-1335
  7. Amiodarone. GlobalRPH. http://www.globalrph.com/amiodarone_dilution.htm.


Ross Donaldson