68 Ripple Mapping the Ventricular Scar: A Novel Approach to Substrate Ablation of Post-infarct Ventricular Tachycardia to Prevent Implantable Defibrillator Therapy

Introduction Ventricular Tachycardia (VT) is a common cause of mortality post myocardial infarction. Any mortality benefit of an implantable cardiac defibrillator (ICD) may be offset by the significant morbidity caused by VT shocks from the device. The VT circuit is dependent upon channels of surviving myocardium within the infarct substrate. As VT is often poorly tolerated, ablation of characteristic electrograms (fractionated and late potentials) associated with these channels in sinus rhythm is preferred to reduce ICD therapies, though recurrence rates remain high. Ripple Mapping (RM) displays all electrogram components from each anatomical point as a dynamic bar that protrudes from its 3D location. We have described how RM might visualize “conducting channels” (RM-CCs) of these characteristic electrograms within the infarcted substrate in a retrospective series. In this study, we used RM prospectively (CARTO3v4™) to characterize the VT substrate to guide ablation. Methods Consecutive pts referred for VT ablation following episodes of sustained VT or ICD therapies post distant MI were included. High point density bipolar LV endocardial electrograms were collected in sinus rhythm or ventricular pacing within the infarct “scar” ( Results 15 consecutive pts (median age 68yrs, LVEF 30%) were studied (6 month pre-procedural ICD therapies: median 19 ATP events (IQR=4–93) and 1 shock (IQR=0–3)). Scar ( Conclusions RM identifies conducting channels within the post-infarct scar that might support re-entrant VT and can be used to guide substrate based ablation to reduce future ICD therapies.