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

Abstract

Background: The role and optimal sequence of ventricular tachycardia (VT) induction, mapping, and ablation when combined with substrate modification is unclear.

Objective: 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.

Methods: 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.

Results: 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).

Conclusion: 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.

Keywords: Catheter ablation; Myocardial infarction; Nonischemic cardiomyopathy; Substrate ablation; Ventricular tachycardia.