Tachycardia (wide)

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Background

  • Consider Hyperkalemia, Dig Toxicity, severe metabolic acidosis
  • Sustained ventricular tachycardia is VT > 30 seconds
  • 3 beats is considered VT; less than 30 seconds is non-sustained VT

Epidemiology[1][2][3]

  • WCT is due to ventricular tachycardia in 80% of cases
  • For patients with underlying cardiac disease, this number increases to > 90%

Differential Diagnosis

Regular

Irregular

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

Evaluation

Ventricular tachycardia
  • Assume ventricular tachycardia until proven otherwise
  • See V Tach vs. SVT

Management

Pulseless: see Adult pulseless arrest

  • Unstable:
    • Regular: Synchronized cardioversion 100-200J
    • Irregular: Unsynchronized cardioversion (defibrillation) 200J
  • Stable
    • Regular (treat as presumed V-tach)
      • Procainamide 100 mg q5min at max rate of 25-50 mg/min[4]
        • Until termination of arrhythmia, then start 2-6 mg/min (or 1-2 mg/min for renal/cardiac failure)
        • OR max 17 mg/kg total dose given (12 mg/kg if renal failure)
        • OR if QRS widens > 50%
      • 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)[5]
        • Then 0.5 mg/min drip over next 18 hrs (540 mg total)
        • Oral dosage after IV infusion depends on IV infusion length:
          • < 1 wk IV infusion: 800-1600 mg PO QD
          • 1-3 wks: 600-800 mg PO QD
          • > 3 wks: 400 mg PO QD
      • Lidocaine 1-1.5mg/kg IV q5min, repeat prn until up to 300mg/hr
    • Irregular (treat as presumed preexcited A-fib)
  • Refractory
    • ≥3 episodes within 24 hours considered electrical storm and may require alternate treatment (i.e. beta blockade, sedation, ablation)
  • In very wide complex (>0.2 msec) and <120 bpm in a patient with significant history, consider giving calcium chloride to treat hyperkalemia and Bicarbonate for Na channelopathy

Disposition

  • Admit all patients (even if converted to NSR with adenosine)

See Also

References

  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. Procainamide. GlobalRPH. http://www.globalrph.com/procainamide_dilution.htm.
  5. Amiodarone. GlobalRPH. http://www.globalrph.com/amiodarone_dilution.htm.