Clinical Electrophysiology -> Ventricular Arrhythmias -> Experimental methods D-AB10 - Ventricular Arrhythmias from Mechanism to New Ablation Targets (ID 52) Abstract Plus

D-AB10-01 - MUSIC CT-guided Stereotactic Radioablation For Ventricular Tachycardia (ID 735)

Abstract

Background: Stereotactic body radiotherapy (SBRT) is a promising therapy for ventricular tachycardia (VT) refractory to catheter ablation. However, designing the radioablation treatment volume to cover the electroanatomical target can be challenging.
Objective: To demonstrate the feasibility of applying MUSIC (Liryc, Bordeaux, Fr) to arrhythmogenic substrate for SBRT treatment planning.
Methods: 4 males, median age 72, with ischemic cardiomyopathy and LVEF 20%(IQR 19-25%), with VT storm after exhausting antiarrhythmic options and failing 3 (IQR 2-4.5) catheter ablations underwent SBRT. MUSIC-reconstructed cardiac CT characterized high yield sites for arrhythmogenesis (severe wall thinning, calcification and fat), and causes for failed catheter ablation (e.g. laminated thrombus) (Panel B, C). Together with ECG of the clinical VT and electroanatomical mapping data (Panel A and D), the radioablative treatment target was defined. MUSIC contours were imported into radiotherapy planning software co-registered with planning CT to ensure coverage of critical arrhythmogenic substrate without collateral organ injury (Panel E).
Results: Median planning treatment volume (PTV) was 319 (IQR 280-330)mL (Panel E), and 25Gy was prescribed. One patient recurred with recalcitrant slow VT below his device detection, and underwent repeat catheter ablation. In the remaining 3 patients, no VT was observed at 3 months post-therapy despite a median of 57 VT episodes and 13 shocks in the preceding 6 months. No treatment related side effects were observed.
Conclusion: In this small series, it was feasible to use MUSIC to facilitate SBRT treatment target delineation and PTV design.
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