Lipomatous metaplasia is the best CT predictor for conducting channel localization in scar-related ventricular tachycardia ablation

Abstract

Abstract Introduction Recent evidence has shown that intramyocardial lipomatous metaplasia (LM) can be directly identified with cardiac computer tomography (CT) and plays a significant role in ventricular arrhythmogenesis and facilitation in structural heart disease. Purpose We sought to explore the diagnostic performance of three different CT features (LM, CT channels, wall thinning) identified at ADAS3D post-processing as electroanatomical substrate predictors and their potential role in planning and aiding ventricular tachycardia (VT) scar dechanneling procedures. Methods All patients undergoing VT ablation at our institution were enrolled. CT images were post-processed with ADAS3D software to assess LM and left ventricle wall thickness. Images were then retrospectively imported into CARTO3 software and concordance between CT and electroanatomical features (conducting channels, channel entrances, bipolar scar, voltage channels, ablation VISITAGs) was assessed at a cardiac segment level. Results From July 2016 to December 2022 131 patients underwent VT ablation at our institution. 88 patients did not undergo preprocedural CT examination, 15 patients had a low-quality CT scan and, at ADAS3D analysis 9 patients did not have significant LM. 19 patients (14 ischemic and 5 non-ischemic, 323 cardiac segments) were then included for analysis. 90 segments (27,86%) showed LM, 93 segments (28,79%) showed thickness < 5 mm and 12 segments (3,72%) held CT channels. In terms of conducting channel prediction, in ischemic patients, LM showed 70% sensitivity, 89% specificity, 73% PPV and 88% NPV when compared to CT channels (10% sensitivity, 98% specificity, 70% PPV, 72% NPV) or wall thinning (61% sensitivity, 82% specificity, 58% PPV and 84% NPV). In non-ischemic patients LM showed with 69% sensitivity, 81% specificity, 39% PPV and 94% NPV when compared to CT channels (15% sensitivity, 100% specificity, 100% PPV, 87% NPV) or wall thinning (46% sensitivity, 82% specificity, 32% PPV and 89% NPV). Overall, at multivariate analysis only LM (OR 12,46 95% C.I. 6,59-23,58) and wall thinning (OR 4,73 95% C.I. 2,45-9,14) were independent predictors for conducting channel. Conclusion Lipomatous metaplasia is the best CT predictor for conducting channel presence both in ischemic and non-ischemic patients with scar related ventricular tachycardia and a potentially useful tool for procedure planning and guidance.CT predictors for EAM substrate findingsMultivariate forest plots