RV tissue heterogeneity on CT a novel tool to identify the VT substrate in ARVC

Abstract

OBJECTIVES This study sought to evaluate whether right ventricular (RV) tissue heterogeneity on computed tomography (CT): 1) is associated with conduction delay in arrhythmogenic right ventricular cardiomyopathy (ARVC); and 2) distinguishes patients with ARVC from those with exercise-induced arrhythmogenic remodeling (EIAR) and control individuals.BACKGROUND ARVC is characterized by fibrofatty replacement, related to conduction delay and ventricular tachycardiac. Distinguishing ARVC from acquired, EIAR is challenging.METHODS Patients with ARVC or EIAR and combined endocardial-epicardiat electroanatomic voltage mapping for VT ablation with CT integration were enrolled. Patients without structural heart disease served as control individuals. Tissue heterogeneity on CT (CT heterogeneity) was automatically quantified within the 2-mm subepicardium of the entire RV free wall at normal sites and tow voltage sites harboring late potentials (LP+) in ARVC/EIAR.RESULTS Seventeen patients with ARVC (15 mates; age: 50 17 years), 9 patients with EIAR (7 males; age: 45 14 years) and 17 control individuals (14 males; age: 50 +/- 15 years) were enrolled. Of 5,215 ARVC mapping points, 560 (11%) showed LP+ . CT heterogeneity was higher at sites with LP-i compared to normal sites (median: 31 HU/mm; IQR: 23 to 46 HU/mm vs. median: 16 HU/mm; IQR: 13 to 21 HU/mm; p < 0.001). The optimal CT heterogeneity cutoff for detection of LP+ was 25 HU/mm (area under the curve [AUG 0.80; sensitivity: 72%; specificity: 78%). Overall CT heterogeneity allowed highly accurate differentiation between patients with ARVC and control individuals (AUC: 0.97; sensitivity: 100%; specificity: 82%) and between ARVC and EIAR (AUC: 0.78; sensitivity: 65%; spedficity: 89%).CONCLUSIONS In patients with ARVC, tissue heterogeneity on CT can be used to identify LP+ as a surrogate for ventricular tachycardia substrate. The overall tissue heterogeneity on CT allows the distinguishing of patients with ARVC from those with EIAR and control individuals. (C) 2020 by the American College of Cardiology Foundation.