Abstract 12905: Epicardial and Intramyocardial Fat as Predictors of Ventricular Arrhythmia in Ischemic and Non-Ischemic Cardiomyopathy

Abstract

Background: Sudden cardiac death from ventricular arrhythmia (VA) is a global concern. While emerging evidence suggests a role for myocardial fat in the development of VA among ischemic (ICM) and non-ischemic cardiomyopathy (NICM) patients, the volume and distribution of epicardial adipose tissue (EAT) and intramyocardial fat (IMF) linked to VA remain underexplored. Objective: To evaluate the predictive value of LV tissue heterogeneity, EAT, and IMF volumes in assessing the risk of VA in ICM and NICM patients. Methods: Patients enrolled in the PROSE-ICD registry, who underwent contrast-enhanced computed tomography were included. The designated endpoint was ventricular arrhythmia, defined as appropriate ICD shock or sudden arrhythmic death. IMF volume (voxels between -180 and -5 HU), EAT volume (voxels between -200 to -50 HU), and myocardial fat tissue heterogeneity (defined as the magnitude of change between nearby voxels) were calculated. Logistic regression models were employed to assess the association between explanatory variables and outcome. Results: 98 patients (47 ICM, 51 NICM) were included with a mean follow up time of 5.6±3.4 years. Participants’ mean age was 56±13.2 years, and 66% were male. LV tissue heterogeneity (per HU/mm) was associated with VA incidence (OR = 1.11; P < 0.01) in the ICM cohort, whereas EAT and IMF volume were associated with VA in the NICM subgroup [(OR = 1.12; P < 0.01), and (OR = 1.21; P = 0.01), respectively]. Even after adjusting for various covariates, LV tissue heterogeneity in the ICM group and EAT in the NICM group maintained a significant association with VA. Conclusion: In ICM, increased fat distribution heterogeneity is associated with VA, while in NICM, increased IMF and EAT volume are linked to a higher risk for VA. These findings suggest that LV tissue heterogeneity and EAT volume offer valuable prognostic insights in cardiomyopathy patients, indicating that the contribution of fat to VA depends on the underlying substrate.