What is the management approach for ventricular tachycardia (V tach)?

Management of Ventricular Tachycardia (V tach)

Immediate synchronized direct current cardioversion is the treatment of choice for patients with ventricular tachycardia who are hemodynamically unstable, presenting with hypotension, altered mental status, or signs of shock. 1

Initial Assessment and Management

Hemodynamically Unstable V tach

• Perform immediate synchronized cardioversion for hemodynamically unstable patients 1
• For patients who are hypotensive but conscious, provide immediate sedation before cardioversion 1
• Use unsynchronized discharge (200J) for polymorphic VT that resembles VF, and synchronized discharge (100J) for monomorphic VT with rates >150 bpm 1
• If V tach recurs after cardioversion, consider antiarrhythmic drug therapy to prevent acute reinitiation 2

Hemodynamically Stable V tach

• For stable patients with monomorphic VT, follow this algorithm:
  1. Confirm diagnosis using ECG criteria (QRS >0.14s with RBBB or >0.16s with LBBB pattern, AV dissociation, fusion beats) 2
  2. Administer IV antiarrhythmic drugs 3, 4:
     • Amiodarone: Initial loading dose of 150mg over 10 minutes, followed by 1mg/min infusion for 6 hours, then 0.5mg/min maintenance 5
     • Alternative: IV procainamide or lidocaine 3, 6
  3. If pharmacological therapy is ineffective or contraindicated, proceed to synchronized cardioversion 2

Special Considerations

Medication Selection

• Prefer IV amiodarone in patients with heart failure or suspected myocardial ischemia 1
• Avoid calcium channel blockers (verapamil, diltiazem) in patients with VT and structural heart disease as they may worsen hemodynamics or precipitate collapse 1, 4
• Amiodarone is indicated for initiation of treatment and prophylaxis of frequently recurring VF and hemodynamically unstable VT in patients refractory to other therapy 5
• Amiodarone dosing requires close monitoring with adjustment as needed - typical starting dose is about 1000mg over first 24 hours 5

Long-term Management

• Consider implantable cardioverter-defibrillator (ICD) for patients with structural heart disease and sustained symptomatic VT, as it's superior to antiarrhythmic drugs for improving overall survival 7
• For patients with idiopathic VT (structurally normal heart), radiofrequency catheter ablation is a reasonable option 7
• Consider urgent catheter ablation in patients with scar-related heart disease presenting with incessant VT or electrical storm 1
• Beta-blockers and/or amiodarone are effective for primary prevention of sudden cardiac death 3

Common Pitfalls and Caveats

• Don't assume a wide-complex tachycardia is supraventricular - when in doubt, treat as VT 2, 8
• Avoid calcium channel blockers for wide-complex tachycardias unless certain they are fascicular VT 1
• Be aware that amiodarone can cause hypotension when infused too rapidly - do not exceed initial infusion rate of 30 mg/min 5
• Most post-MI VT occurs within the first 48 hours; sustained VT outside this timeframe requires careful evaluation 1
• Amiodarone must be delivered by volumetric infusion pump, preferably through a central venous catheter 5
• For infusions longer than 1 hour, do not exceed amiodarone concentrations of 2 mg/mL unless using a central venous catheter to avoid peripheral vein phlebitis 5