Is ventricular tachycardia (VTach) with a pulse immediately shockable?

Management of Ventricular Tachycardia with Pulse

Ventricular tachycardia (VT) with a pulse is not immediately shockable and should be treated with synchronized cardioversion rather than defibrillation. 1

Differentiating Treatment Based on Hemodynamic Status

Hemodynamically Unstable VT with Pulse

• Immediate synchronized cardioversion is recommended
• Initial energy: 100J (biphasic) or 200J (monophasic)
• If unsuccessful, increase energy in stepwise fashion 1, 2
• Establish IV access before cardioversion if possible and administer sedation if patient is conscious (but do not delay cardioversion if extremely unstable) 1

Hemodynamically Stable VT with Pulse

• Pharmacological therapy can be attempted first 2
• Options include:
  • Procainamide: recommended for patients without severe CHF or acute MI 1
  • Amiodarone: recommended for patients with or without severe CHF or acute MI 1
  • Sotalol: may be considered for stable monomorphic VT 1
  • Lidocaine: particularly useful when VT is associated with acute ischemia 2

Important Distinctions in VT Management

Monomorphic vs. Polymorphic VT

• Monomorphic VT with pulse: Treat with synchronized cardioversion 1
• Polymorphic VT: Cannot be synchronized - treat as VF with unsynchronized high-energy shocks (defibrillation) 1

Synchronized vs. Unsynchronized Cardioversion

• Synchronization times the shock with the QRS complex to avoid shock delivery during the relative refractory period 1
• Synchronization prevents the shock from inducing VF 3
• Research shows shocks delivered within 100ms of the QRS peak have a 93% success rate compared to 42% for shocks outside this window 3

Technical Considerations for Cardioversion

• For monomorphic VT with pulse, start with 100J (biphasic) or 200J (monophasic) 1
• If unsuccessful, increase energy in stepwise fashion 1
• Success rates for cardioversion are higher for slower VT (<200 bpm) compared to faster VT (>200 bpm) 4

Common Pitfalls to Avoid

1. Misclassification error: Never use synchronized cardioversion for pulseless VT or polymorphic VT - these require defibrillation 1
2. Synchronization failure: If synchronization is impossible and the patient is extremely unstable, use unsynchronized shocks (defibrillation doses) 1
3. Delay in treatment: Do not delay cardioversion if the patient is extremely unstable 1
4. Inappropriate energy selection: Using too low energy for faster VTs may result in failure to convert 4
5. Medication errors: Avoid calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardias of unknown origin 2

Special Considerations

• For pregnant patients with VT, perform manual left uterine displacement during CPR if needed 2
• For VT associated with long QT syndrome (Torsades de Pointes), correct electrolytes, administer IV magnesium, and consider pacing 2
• Always have a defibrillator available when treating VT, as deterioration to VF can occur 3

By following these guidelines, clinicians can appropriately manage VT with a pulse, optimizing patient outcomes while minimizing risks associated with electrical therapy.