P5693Critical sites for scar-related ventricular tachycardias treatment: an approach based on sinus rhythm late activation zones

Introduction Despite advances in antiarrhythmic and device therapy, ventricular tachycardia (VT) is a major cause of increased morbidity and mortality. During scar-mediated monomorphic VT ablation, the search for critical isthmus sites continues to be the primary goal during successful ablative procedures. However, catheter ablation based on conventional mapping techniques is associated with low success rates and is limited to patients with stable VT. Objective The aim of the study was to evaluate, in patients with history of VT, the success of a strategy based on substrate mapping and ablation during sinus rhythm. Methods Retrospective single center analysis of patients undergoing VT ablation from November 2015 to November 2017. Clinical profiles and procedural details were determined. We used high-density structural map to identify voltage abnormalities as well a functional map of sinus rhythm activation to identify the regions of late potentials. Radiofrequency applications were performed in the areas with the latest activation. Recurrence of VT was considered the end-points of the follow-up. Results A total of 22 patients were included in the analysis, 95% male, with an median age of 65,5 (57–71) years old. The majority of the patients (18) with ischemic cardiomyopathy, 3 with nonischemic cardiomyopathy, and 1 with arrhythmogenic right ventricular cardiomyopathy were included. Epicardial mapping was performed in 27% of the cases. CARTO mapping system was used in 10 patients and Rhythmia in the remaining cases. Areas with the latest activation corresponded to regions of abnormal voltage in 21 patients. During a 26,5 (21,5–29,3) months of follow-up, the observed VT recurrence rate was 35%. 25% of the patients needed hospital admission due to arrhythmias and one patient died due to an arrhythmic cause. Treatment success was higher in epicardial approach (100% VS 50%, p=0,03). The location of the scar in the left ventricle was not a determinant of success (anterior-66,7% VS lateral/inferior-61,5%, p=0,806). Conclusion A substrate-based approach that targets regions of late activation within the scar seems attractive and may be a simple way to perform VT ablation with success. In our population, this strategy seams successful, especially in epicardial approach. Substrate modification strategies aiming to eradicate all potential reentrant circuits may be the most successful way to treat VT and avoid recurrences.