What are the treatments for ventricular tachycardia?

Treatment of Ventricular Tachycardia

For ventricular tachycardia (VT), immediate synchronized electrical cardioversion is the first-line treatment for hemodynamically unstable patients, followed by intravenous amiodarone as the most effective antiarrhythmic agent for prevention of recurrence. 1

Initial Assessment and Management

Hemodynamically Unstable VT

1. Immediate synchronized electrical cardioversion

   • Start with 100 J, escalate to 200 J, then 360 J if unsuccessful 1
   • Provide appropriate sedation if patient is conscious 1
   • For pulseless VT, follow VF protocol with immediate defibrillation 2

2. Post-cardioversion pharmacological management

   • Intravenous amiodarone (first-line):
     • 300 mg IV bolus over 10 minutes
     • Followed by 1 mg/min infusion for 6 hours
     • Then 0.5 mg/min maintenance 1
     • Additional 150 mg IV dose if VT recurs 1

Hemodynamically Stable VT

1. Pharmacological options:

   • Intravenous amiodarone: First-line for patients with heart failure or suspected ischemia 2, 3
   • Intravenous procainamide: Reasonable initial treatment for stable sustained monomorphic VT
     • Administered at 30 mg/min to total dose of 17 mg/kg 1, 4
     • Monitor blood pressure and cardiovascular status closely
   • Intravenous lidocaine:
     • 1-1.5 mg/kg IV bolus, followed by 2-4 mg/min infusion 1
     • Particularly effective for VT associated with acute myocardial ischemia 1
     • Follow with 20 ml saline bolus when delivered through peripheral vein 2

2. Special considerations:

   • For LV fascicular VT (RBBB morphology with left axis deviation): Use intravenous verapamil or beta-blockers 2
   • For Torsades de Pointes: Intravenous magnesium (8 mmol bolus followed by 2.5 mmol/h infusion) 2, 1

Refractory VT Management

1. Catheter ablation:

   • Urgent catheter ablation recommended for incessant VT or electrical storm in patients with scar-related heart disease 2
   • Recommended for recurrent ICD shocks due to sustained VT in patients with ischemic heart disease 2
   • Should be considered after first episode of sustained VT in patients with ischemic heart disease and an ICD 2

2. Additional interventions:

   • Overdrive pacing
   • General anesthesia
   • Urgent coronary angiography with revascularization (if ischemia suspected) 1
   • Combination therapy with intravenous amiodarone and beta-blockers may be reasonable for VT storm 1

Specific VT Scenarios

1. Polymorphic VT:

   • Intravenous beta-blockers are particularly effective and considered the single most effective therapy for polymorphic VT storm 1

2. Ischemia-related VT:

   • Intravenous lidocaine (1-1.5 mg/kg bolus, followed by 2-4 mg/min infusion) 1
   • Consider urgent revascularization when myocardial ischemia cannot be excluded 1

3. Electrolyte management:

   • Correct hypokalemia and hypomagnesemia
   • Consider potassium repletion to 4.5-5 mmol/L for patients with torsades de pointes 1

Important Cautions

1. Avoid calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardias of unknown origin, especially with history of myocardial dysfunction 1

2. Monitor for drug toxicity:

   • Lidocaine: CNS effects
   • Amiodarone: Hypotension, bradycardia, QT prolongation, and hepatotoxicity 1
   • Procainamide: Serious hematological disorders, particularly leukopenia or agranulocytosis 4

3. Efficacy considerations:

   • Despite widespread use, research suggests IV amiodarone may be poorly effective for acute termination of sustained monomorphic VT (29% success rate in one study) 5
   • However, amiodarone remains recommended by guidelines for prevention of recurrence 1, 3

Long-term Management

1. Transition to oral therapy:

   • Patients may be transferred to oral amiodarone therapy after initial IV treatment 3
   • Long-term oral amiodarone can be effective in 69-75% of patients with VT refractory to conventional antiarrhythmic drugs 6

2. Monitoring:

   • Continuous cardiac monitoring during and after treatment
   • Assess for underlying causes of VT (ischemia, electrolyte abnormalities, drug toxicity)
   • Consider electrophysiology studies for sustained VT occurring >48 hours after MI 1