Relationship between MDCT-imaged myocardial fat and ventricular tachycardia substrate in arrhythmogenic right ventricular cardiomyopathy

Background-myocardial fibrofatty infiltration is a milieu for ventricular tachycardia (vt) in arrhythmogenic right ventricular cardiomyopathy (arvc) and can be depicted as myocardial hypodensity on contrast-enhanced multidetector computed tomography (mdct) with high spatial and temporal resolution. this study aimed to assess the relationship between mdct-imaged myocardial fat and vt substrate in arvc. methods and results-we studied 16 patients with arvc who underwent ablation and preprocedural mdct. high-resolution imaging data were processed and registered to high-density endocardial and epicardial maps in sinus rhythm on 3-dimensional electroanatomic mapping (3d-eam) (626±335 and 575±279 points/map,respectively). analysis of the locations of low-voltage and fat segmentation included the following endocardial and epicardial regions: apex,mid (anterior,lateral,inferior),and basal (anterior,lateral,inferior). the location of local abnormal ventricular activities (lava) was compared with fat distribution. rv myocardial fat was successfully segmented and integrated with 3d-eam in all patients. the j agreement test demonstrated a good concordance between the epicardial low voltage and fat (κ=0.69,95% ci 0.54 to 0.84),but fair concordance with the endocardium (κ=0.41,95% ci 0.27 to 0.56). the majority of lava (520/653 [80%]) were located within the rv fat segmentation,of which 90% were not farther than 20 mm from its border. registration of mdct allowed direct visualization of the coronary arteries,thus avoiding coronary damage during epicardial radiofrequency delivery. conclusions-the integration of mdct-imaged myocardial fat with 3d-eam provides valuable information on the extent and localization of vt substrate and demonstrates ablation targets clustering in its border region. © 2014 the authors.