Endocardial (ENDO)-only ventricular tachycardia (VT) ablation has been found to indicate long-term VT-free survival in more than half of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and more than 75% if VT noninducibility is achieved following ablation, according to the results of a study presented at Heart Rhythm 2024 and simultaneously published in JACC: Clinical Electrophysiology.

The study, conducted at the Hospital of the University of Pennsylvania between 1998 and 2020, collected information on 74 ARVC patients (75.7% men; mean age 43.8 years; mean left ventricular ejection fraction [LVEF] 54.6%) who underwent an ENDO-only first catheter ablation with the end goal of achieving noninducibility of monomorphic VT. ARVC was determined by the 1994 and then 2010 Task Force Criteria (mean task force criteria score 5.9).

Noninducibility was assessed at the end of the procedure using single, double and triple extrastimuli. Induced polymorphic VT (≤230 ms unless it was the baseline arrythmia induced) was considered noninduced monomorphic VT for the purposes of the study. Ventricular noninducibility was achieved in 49 patients (68.1%) and not assessed in two.

Results showed that the primary endpoint, relief from any recurrent sustained ventricular arrythmia (including monomorphic and polymorphic VT and ventricular fibrillation) from baseline to a median follow-up of 6.6 years (IQR 3.4-11.2) was achieved in 40 (54.1%) patients. Among the patients with VT noninducibility at last ENDO procedure, VT-free survival was heightened to 75.5%.

Nine additional patients (12.2%) had rare VT episodes. Five (6.8%) had a single episode and four (5.4%) had two episodes; 50% of recurrences occurred during the first year of follow-up. Of the 29 patients who had more than one VT, 23 (31.1%) needed a subsequent EPI ablation, a secondary endpoint.

Other secondary endpoints included need for a heart transplant and death from any cause. Eight patients (10.8%) underwent heart transplant at a mean of 5.1 years after their last ENDO ablation procedure.

Nine patients (12.2%) died of refractory heart failure at a mean of 9.7 years after their last ENDO ablation procedure. Five of these patients were free from VT recurrence, and the other four had experienced their last VT episodes more than year before their deaths. Seven suffered from biventricular heart failure, and the other two from right ventricular failure.

Multivariable analysis showed that age >45 years at diagnosis (hazard ratio [HR], 0.41; 95% CI, 0.17-0.98; p=0.045) and VT noninducibility (HR, 0.36; 95% CI, 0.16-0.80; p=0.012) were significantly associated with VT-free survival.

"Our data would suggest," study authors Corentin Chaumont, MD, et al., write, "the soundness of a stepwise approach to VT ablation in patients with ARVC and proceeding to EPI ablation in those without an endocardial VT substrate or in patients with persistent inducible VT only after endocardial ablation, particularly if elderly." They add that, "the ENDO approach should remain an essential part of the ablation strategy."