Ventricular tachycardia substrate ablation in patients with slightly depressed left ventricular ejection fraction. Predictors of VT-free survival in a prospective multicentre registry

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: There is no consensus about the need for ICD implantation in patients with slightly depressed left ventricle ejection fraction (LVEF) after catheter ablation for hemodynamically tolerated ventricular tachycardia (VT). PURPOSE: This study aims to investigate predictors of mortality VT-free survival in this population. METHODS: We evaluated predictors of VT-free survival in patients with LVEF>40% from a prospective multicenter register of patients undergoing VT substrate ablation for hemodynamically tolerated VT. Decision to protect with ICD implantation at hospital discharge was performed according to the judgment of the treating cardiologist. The patients included in the study were followed every six months. Ventricular arrhythmia-free survival was the primary endpoint. Any episode of sustained VT (> 30 s) or appropriate ICD therapy was considered VT recurrence. RESULTS: One-hundred thirty-two patients [67±13 years, 91% male, 50±8% mean LVEF, 85 (65%) with ischemic heart disease] with a LVEF>40% were identified. Twenty-one (16%) of them were non-inducible at the end of the procedure and were discharged without ICD implantation as they were considered to have a low risk of recurrences. After a mean follow-up of 26±23 months, 32 (24%) patients had VT recurrences. A complete arrhythmogenic substrate elimination [HR: 0.34 (0.16-0.7), p<0.01] and the use multiple ventricular extrastimuli for hidden slow conduction (HSC) identification and ablation [HR: 0.51 (0.27-1.1), p=0.09] were related with VT-free survival (Figure 1). 53 (40%) patients fulfilled both criteria, having a 8% recurrence rate during the follow-up. Compared with the clinical decision making of ICD implantation at hospital discharge, the use of these two variables better identify patients at risk for VT recurrences, with a net reclassification improvement of 23% (Figure 2). CONCLUSIONS: VT recurrence after VT substrate ablation in patients with slightly depressed LVEF remains high. However, complete substrate elimination and HSC analysis and ablation are related with higher VT-free survival and identify a subgroup of patients in whom ICD might be not beneficial. [Figure: see text] [Figure: see text]