Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia

In patients with ischemic cardiomyopathy needing an implantable cardioverter-defibrillator (ICD), both catheter ablation and antiarrhythmic drugs (AADs) have been shown to reduce ICD shocks but, the most effective method remains ambiguous.

The aim of this study was to evaluate the efficacy and safety of catheter ablation procedure vs AAD as the first-line strategy in ICD patients with symptomatic ventricular tachycardias (VTs).

These data support the effectiveness of both catheter ablation and AAD in reducing mortality and preventing ICD therapies and ICD shocks, but suggest that catheter ablation leads to fewer adverse events and cardiac hospitalisations.

Substrate-based catheter ablation should be considered before AAD as a first-line treatment for patients with ischemic cardiomyopathy and symptomatic VT.

SURVIVE-VT (NCT03734562) was a phase IV, randomised controlled trial conducted at 9 centres specialised for performing VT substrate catheter ablation in Spain. Eligible patients were randomly assigned (1:1) to receive catheter ablation or AAD therapy. Patients undergoing ablation had their procedure scheduled within 15 days and patients in the AAD group initiated their treatment immediately.

• Composite of cardiovascular death, appropriate ICD shock, unplanned hospitalisation for worsening heart failure, or severe treatment-related complications from enrolment up to 24-month follow-up

• Sustained VT or ventricular fibrillation, appropriate and inappropriate ICD therapies, death from any cause, unplanned hospitalisation for ventricular arrhythmias and cardiac events, change in ventricular ejection fraction, and quality of life

• Previous myocardial infarction (>6 weeks)
• Optimal medical treatment (if ventricular dysfunction)
• An episode of very symptomatic VT defined as:
  • sustained VT treated using ICD shock (<6 months)
  • sustained VTs with syncope, even if terminated with antitachycardia pacing
• Monomorphic VT necessitating ICD (added in 2013 as a new qualifying criterion)

• 144 patients (median age, 70 years; 96% male) were randomised to catheter ablation (n=71) or AAD (n=73)
• Baseline characteristics between the trial groups were well balanced
• At 24 month, 28.2% of patients in the ablation group and 46.6% in the AAD group experienced the primary outcome [hazard ratio (HR), 0.52; 95% confidence interval (CI), 0.30–0.90; p= 0.021] with a significant decrease in severe treatment-related complications (9.9% vs 28.8%; HR, 0.30; 95% CI, 0.13–0.71; p=0.006)
• The number of patients hospitalised for heart failure were 8 in the ablation group and 13 in the AAD group (HR, 0.56; 95% CI, 0.23–1.35; p=0.198).
• No significant differences were observed in cardiac mortality between treatment arms
• Compared to AAD therapy, catheter ablation significantly redcued the recurrence as VT storm, incessant VT, and/or slow undetected VT, and hospital admissions for ventricular arrhythmias (HR, 0.21; 95% CI, 0.08–0.57; p=0.002), and any cardiac hospitalisation  

In patients with ischemic heart disease and symptomatic VT, substrate-based catheter ablation vs AAD significantly reduced the composite efficacy and safety endpoint of ICD shocks, cardiovascular death, hospitalisation for worsening heart failure, and severe treatment-related adverse events, and improved hospitalisation for cardiovascular causes.

• Enrolment was lengthier than expected and the population size was inferior to the approximation
• Only a small number of specialised centres participated
• Some analyses were performed post hoc
• The trial does not provide data on the appropriate time to treat patients with ICD therapies