218-04: Substrate Ablation Before or After Ventricular Tachycardia Induction and Ablation. A Randomized Study

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Background: Ventricular tachycardia (VT) induction and mapping as the first step in VT ablation procedures remains standard practice. However, the role and the optimal sequence of VT induction and ablation when combined with substrate ablation during procedures remains unclear. Methods and Results: Forty-eight consecutive patients with structural heart disease and clinical VTs were included and randomized to a simplified substrate ablation procedure with scar dechanneling as the first step (group 1, n = 24) or standard procedure with VT induction and ablation followed by scar dechanneling afterwards (group 2, n = 24). Thirty-eight patients had coronary artery disease, 10 non-ischemic cardiomyopathy and 1 arrhythmogenic right ventricular dysplasia. Prior to substrate ablation, 32 VTs were induced and targeted for ablation in 23 patients of the group 2. Procedure time (209 ± 70 min. vs. 262 ± 63 min., P = 0.009), fluoroscopy time (14 ± 6 min. vs. 21 ± 9 min, P = 0.005) and the need for electrical cardioversion (25% vs 54%, P = 0.039) were lower in group 1. After substrate ablation, 16 (66%) patients from group 1 and 12 (50%) from group 2 were non-inducible (P = 0.242). After residual inducible-VT ablation the percentage of patients with acute procedure success was 87.5% in group 1 and 70.8% in group 2 (P = 0.155). There were no differences in VT recurrence rate between groups during a mean follow-up of 22 ± 14 months (log rank P= 0.557). Conclusion: VT induction and mapping prior to substrate ablation prolongs the procedure, radiation exposure and the need for of electrical cardioversion; without benefit in terms of acute and long-term outcomes.