ABLATION OF TREATMENT-REFRACTORY VT USING CT SUBSTRATE MAPPING, AUTOMATED ECG LOCALIZATION AND INFUSION NEEDLE CATHETER ABLATION

Abstract

Catheter ablation of VT related to deep myocardial substrate can be challenging, but could be facilitated by techniques to identify and ablate intramyocardial substrate. We have previously described an automated method for localizing induced VT based on integrals of the initial portion of the QRS, with patient-specific regression coefficients calculated by pacing from known intracardiac sites. CT imaging with 3D reconstruction can be helpful to plan suitable ablation targets. Infusion needle ablation can be used to ablate deep myocardial substrate. We explored feasibility of combining 3D scar reconstruction with automated VT localization and intramural infusion needle ablation. In a patient with prior CABG and 3 failed endocardial ablations, a delayed contrast CT was analysed using MUSIC software. Ablation was performed using an infusion needle catheter, and locations of sites of successful ablation were compared to predicted sites using automated software. Of 8 VTs induced, 4 were terminated with RF and included in the analysis. VTs 1 & 2 were localised to the mid-anterolateral wall at the superior border of imaged scar within 1mm of the site of termination with needle ablation. VT 6 was localised to the superior margin of basal septal scar 8 mm from the site of termination with needle RF. VT 7 was localised to the apical inferoseptum at the margin of a thinned segment, 8 mm from the successful needle ablation site. Noninvasive anatomic substrate imaging, automated VT localization and delivery of targeted intramyocardial ablation lesions could facilitate successful VT ablation.