Abstract 14174: MRI-Based Patient-Specific Virtual Electrophysiology Laboratory for Scar-Related Ventricular Tachycardia
In scar-related ventricular tachycardia (VT), there is a heterogeneous zone (HZ), which is a highly complex mixture of scar and normal-appearing tissue. A part of HZ may be the region of slow conduction that serves as the substrate for reentry. Currently, we use invasive catheter mapping to ‘search and destroy’ this slowly conducting tissue. Our aim is to investigate the role of the MRI-defined HZ as the ablation target for scar-related VT by utilizing MRI-based computational simulations. In 13 patients with scar-related VT (age 65 ± 9 years, ejection fraction 42 ± 16 %) referred for VT ablation, pre-ablation MRI with late gadolinium enhancement (LGE) was performed. With LGE, the scar was defined as the myocardium with signal intensity (SI)>50% of the peak SI within the myocardium, and HZ was defined as the myocardium with SI>peak SI in the remote normal myocardium but <50% of the peak SI within the myocardium. Scar and HZ were integrated into computational simulation. The scar was modeled as an insulator, and HZ as the slowly conducting tissue. Myofiber orientation was estimated from the ventricular geometry. Simulation results were validated against electrophysiology study, mapping, and actual 12-lead ECG data. VT was induced in simulation by simulated programmed electrical stimulation in each patient. Simulated surface 12-lead ECG of the induced VT matched well with the actual surface ECG of the clinical VT. Ablation lesions were simulated by creating areas of insulation in the computational model. Simulated programmed electrical stimulation was done after each simulated ablation to determine if VT was no longer inducible. In all cases, the successful ablation sites that terminated the clinical VT in the actual ablation procedure coincided with the optimal ablation targets predicted by the simulation results. We conclude that, using pre-ablation MRI, scar-related VT can be reproduced in computer simulation and successful ablation sites can be accurately determined.
- © 2011 by American Heart Association, Inc.