Substrate modification or ventricular tachycardia induction, mapping, and ablation as the first step? A randomized study

Abstract

The role and optimal sequence of ventricular tachycardia (VT) induction, mapping, and ablation when combined with substrate modification is unclear. The purpose of this study was to test the benefits of starting the scar-related VT ablation procedure with substrate modification vs the standard protocol of VT induction, mapping, and ablation as the first step. Forty-eight consecutive patients with structural heart disease and clinical VTs were randomized to simplified substrate ablation procedure with scar dechanneling as the first step (group 1, n = 24) or standard procedure with VT induction, mapping, and ablation followed by scar dechanneling (group 2, n = 24). Procedure and fluoroscopy times, the need for external cardioversion, acute results, and VT recurrence during follow-up were compared between groups. Thirty-seven patients had ischemic cardiomyopathy, 10 nonischemic cardiomyopathy, and 1 arrhythmogenic cardiomyopathy. Before substrate ablation, 32 VTs were induced and targeted for ablation in 23 patients of group 2. Procedure time (209 ± 70 minutes vs 262 ± 63 minutes; P = .009), fluoroscopy time (14 ± 6 minutes vs 21± 9 minutes; P = .005), and electrical cardioversion (25% vs 54%; P = .039) were lower in group 1. After substrate ablation, 16 patients (66%) of group 1 and 12 patients (50%) of group 2 were noninducible (P = .242). End-procedure success (after residual inducible VT ablation) was achieved in 87.5% and 70.8% of patients, respectively (P = .155). There were no differences in VT recurrence rate between groups during a mean follow-up of 22 ± 14 months (log rank, P = .557). VT induction and mapping before substrate ablation prolongs the procedure, radiation exposure, and the need for electrical cardioversion without improving acute results and long-term ablation outcomes.