When is catheter ablation for ventricular tachycardia (VT) recommended?

Catheter Ablation for Ventricular Tachycardia: Recommendations and Indications

Catheter ablation is strongly recommended for patients with incessant VT, electrical storm resulting in ICD shocks, or hemodynamically unstable VT refractory to medications, as it significantly reduces mortality and morbidity in these critical scenarios. 1

Primary Indications for Catheter Ablation

Catheter ablation is indicated in the following scenarios:

• Urgent/Emergency Indications:

  • Incessant VT or electrical storm with ICD shocks
  • Hemodynamically unstable VT refractory to medications
  • VT storm (≥3 episodes within 24 hours)

• Specific VT Subtypes:

  • Bundle-branch reentrant VT
  • Symptomatic outflow tract VT
  • Symptomatic VA arising from papillary muscles
  • Verapamil-sensitive idiopathic LV tachycardia
  • Recurrent episodes of idiopathic VF
  • PVC-induced cardiomyopathy 1

• Recurrent VT Despite Medication:

  • VT occurring despite amiodarone therapy (catheter ablation is superior to escalating antiarrhythmic therapy in this scenario) 2
  • Recurrent VT causing ICD shocks despite first-line antiarrhythmic therapy 2

Patient Selection and Expected Outcomes

The success of catheter ablation varies based on underlying etiology:

• Post-MI Scar VT:

  • Better outcomes compared to non-ischemic cardiomyopathy
  • Acute success rates: 41-81%
  • Freedom from VT at 6 months: 46-53% 1

• Risk Stratification:

  • ICD implantation should be considered in eligible patients undergoing catheter ablation, as recurrence risk remains significant 1
  • Patients with ischemic cardiomyopathy have better ablation outcomes than those with non-ischemic cardiomyopathy 1

Procedural Approach

The ablation strategy should include:

1. Mapping Techniques:

   • Activation mapping during ongoing VT (when hemodynamically tolerated)
   • Substrate ablation in sinus rhythm (for unstable VT)
   • Three-dimensional electro-anatomical mapping systems
   • Non-contact mapping when needed 1

2. Ablation Strategies:

   • Point-by-point ablation
   • Linear lesion sets
   • Targeting of local abnormal ventricular activity
   • Epicardial mapping and ablation (particularly in DCM or ARVC) 1

Potential Complications

Important risks to consider include:

• Damage to coronary vasculature
• Inadvertent puncture of surrounding organs
• Left phrenic nerve palsy
• Pericardial tamponade 1

Timing of Ablation: Preventive vs. Deferred

The BERLIN VT trial compared preventive VT ablation (before ICD implantation) to deferred ablation (after 3 ICD shocks):

• Preventive ablation did not significantly reduce mortality or hospitalization for arrhythmia/heart failure compared to deferred ablation
• However, preventive ablation showed trends toward reduced sustained ventricular tachyarrhythmias (39.7% vs 48.2%) and appropriate ICD therapy (34.2% vs 47.0%) 3

Ablation vs. Antiarrhythmic Drugs

The VANISH trial demonstrated:

• For patients with prior MI, ICD, and VT despite first-line antiarrhythmic therapy, catheter ablation resulted in a 28% relative risk reduction in the composite endpoint of death, VT storm, and appropriate ICD shock
• Patients with VT despite amiodarone had better outcomes with ablation compared to increasing amiodarone dose or adding mexiletine 2

Clinical Algorithm for VT Management

1. First-line therapy for all VT patients:

   • Immediate synchronized cardioversion for unstable VT
   • ICD implantation with appropriate programming for eligible patients
   • Beta-blockers for all patients without contraindications 1

2. For recurrent VT despite first-line therapy:

   • If on sotalol and experiencing VT: Consider either catheter ablation or amiodarone
   • If on amiodarone and experiencing VT: Proceed to catheter ablation (superior to escalating antiarrhythmic therapy) 2

3. For specific urgent scenarios (proceed directly to ablation):

   • Electrical storm
   • Incessant VT
   • VT below ICD detection rate
   • Hemodynamically stable but recurrent VT 1, 2

Post-Procedure Management

• Continuous cardiac monitoring for 24-48 hours
• Maintenance antiarrhythmic therapy for 6-24 hours
• Consider chronic oral antiarrhythmic therapy
• Oral beta-blockers should be administered during hospital stay and continued thereafter 1

The ongoing VANISH2 trial is investigating whether ablation is superior to antiarrhythmic drugs as first-line therapy for VT in ischemic cardiomyopathy, which may further refine these recommendations in the future 4.