LAUSR

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular tachycardias(VT) are life-theatening cardiac arrhythmias. Catheter ablation, the standard approach to VT is relying heavily on maps depicting intracardiac signals. The current mapping approach was based on bipolar electrograms, which are massively influenced by the direction of the underlying tissue activation. The omnipolar (OT) electrogram method was recently proposed to generate orientation-independent electrograms and has shown improved results in recent publications (1-2). We describe the first cohort of patients ablated for VT with the help of an OT-enabled catheter. Purpose To evaluate acute and mid-term follow-up of patients ablated for VT using an OT enabled mapping system. Methods Eighteen patients (age 65 ± 19; 2 females, 32% nonischemic, median ejection fraction 40), underwent catheter ablation for scar-related VT. 50% (9) n patients had previous ablation, 4 of which underwent epicardial access. High-density omnipolar maps were obtained with an HD-grid catheter after which ablation was performed with an irrigated-tip catheter. In all patients the ablation was primarily substrate-based with the support of CT scan scar visualization. In 18 patients local abnormal ventricular activities (LAVA) ablation was performed (3), while one patient showed no LAVA. In 7 patients VT mapping was possible due to stable blood pressure during the tachycardia. The median radiofrequency application duration was 36 min. While all patients except one were inducible at the beginning of the procedure, only 3 patients were inducible at the end with a protocol using up to 3 extrastimuli. Follow-up was available in 13 patients (7.1 ± 2.5 months) with 66% freedom from VT recurrence (60% in redo cases and 71% in first procedures). Conclusion OT is a reliable method to visualize signals and perform a substrate-based ablation in with good acute and mid-term outcomes. Future studies will evaluate the impact on long term outcomes. Omnipolar map of a VT