Substrate-Based Ablation Versus Ablation Guided by Activation and Entrainment Mapping for Ventricular Tachycardia: A Systematic Review and Meta-Analysis

Introduction: Substrate-based ablation for scar-related ventricular tachycardia (VT) has gained prominence: however, there is limited data comparing it to ablation guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs. We compared the acute procedural efficacy and outcomes of predominantly substrate-based ablation versus ablation guided predominantly by activation and entrainment mapping. Methods and Results: Database searches through April 2016 identified 6 eligible studies (enrolling 403 patients, with 1 randomized study) comparing the 2 strategies. The relative risk of VT recurrence at follow-up was assessed as the primary outcome using a random-effects meta-analysis. Secondary endpoints of acute success (based on noninducibility of VT), procedural complications, and mortality were assessed using weighted mean difference with the random effects model. At a median follow-up of 18 months, the relative risk (RR) of VT recurrence was not significantly different with substrate-based versus activation/entrainment guided VT ablation (0.72, 95% confidence interval [CI] 0.44–1.18), P = 0.2). Acute success (RR 1.02, 95% CI 0.95–1.1, P = 0.6), procedural complications (RR 0.8, 95% CI 0.35–1.82, P = 0.5) cardiovascular mortality and total mortality did not differ significantly (RR 0.83, 95% CI 0.38–1.79, P = 0.6 and RR 0.76, 95% CI 0.36–1.59, P = 0.5, respectively). Conclusions: This meta-analysis demonstrates similar acute procedural efficacy, and complications, VT recurrence and mortality rates when comparing a predominantly substrate-based ablation strategy to a strategy guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs.