Association of epicardial and intramyocardial fat with ventricular arrhythmias

Background Among ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM) patients, myocardial fibrosis is associated with an increased risk for VA. Growing evidence suggests that myocardial fat contributes to ventricular arrhythmogenesis. However, little is known about the volume and distribution of epicardial adipose tissue and intramyocardial fat and their relationship with VAs. Objective This study aimed to assess the association of contrast-enhanced computed tomography (CE-CT) derived LV tissue heterogeneity, epicardial adipose tissue volume, and intramyocardial fat volume with the risk of VA in ICM and NICM patients. Methods Patients enrolled in the PROSE-ICD registry who underwent CE-CT were included. Intramyocardial fat volume (voxels between -180 and -5 HU), epicardial adipose tissue volume (between -200 to -50 HU), and LV tissue heterogeneity were calculated. The primary endpoint was appropriate ICD shocks or sudden arrhythmic death. Results Among 98 patients (47 ICM and 51 NICM), LV tissue heterogeneity was associated with VA (OR = 1.10, P = .01), particularly in the ICM cohort. In the NICM subgroup, epicardial adipose tissue and intramyocardial fat volume were associated with VA (OR = 1.11, P = .01, OR = 1.21, P = .01) but not in the ICM patients (OR = 0.92, P =.22, and OR = 0.96, P =.19). Conclusion In ICM patients, increased fat distribution heterogeneity is associated with VA. In NICM patients, an increased volume of intramyocardial fat and epicardial adipose tissue is associated with a higher risk for VA. Our findings suggest that fat's contribution to VAs depends on the underlying substrate. Among ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM) patients, myocardial fibrosis is associated with an increased risk for VA. Growing evidence suggests that myocardial fat contributes to ventricular arrhythmogenesis. However, little is known about the volume and distribution of epicardial adipose tissue and intramyocardial fat and their relationship with VAs. This study aimed to assess the association of contrast-enhanced computed tomography (CE-CT) derived LV tissue heterogeneity, epicardial adipose tissue volume, and intramyocardial fat volume with the risk of VA in ICM and NICM patients. Patients enrolled in the PROSE-ICD registry who underwent CE-CT were included. Intramyocardial fat volume (voxels between -180 and -5 HU), epicardial adipose tissue volume (between -200 to -50 HU), and LV tissue heterogeneity were calculated. The primary endpoint was appropriate ICD shocks or sudden arrhythmic death. Among 98 patients (47 ICM and 51 NICM), LV tissue heterogeneity was associated with VA (OR = 1.10, P = .01), particularly in the ICM cohort. In the NICM subgroup, epicardial adipose tissue and intramyocardial fat volume were associated with VA (OR = 1.11, P = .01, OR = 1.21, P = .01) but not in the ICM patients (OR = 0.92, P =.22, and OR = 0.96, P =.19). In ICM patients, increased fat distribution heterogeneity is associated with VA. In NICM patients, an increased volume of intramyocardial fat and epicardial adipose tissue is associated with a higher risk for VA. Our findings suggest that fat's contribution to VAs depends on the underlying substrate.