Abstract 15362: Epicardial Adipose Tissue Effects on Systolic Function: A Direct or Systemic Metabolic Effect?

Abstract

Introduction: Obesity is associated with increased epicardial adipose tissue (EAT). It is unknown if this ectopic fat deposit has direct cardiotoxic paracrine effects on regional systolic function. We have previously shown that EAT mediates diastolic dysfunction via systemic effects, rather than localized effects. We similarly hypothesized regional EAT deposits would have no effect on the left ventricular (LV) strain of adjoining myocardial segments. Methods: We studied 28 obese healthy adults (mean age 48 ± 5 yrs, BMI 38.2 ± 5.0 kg/m 2 ). EAT was quantified on each individual MRI slice from base to apex and summed to obtain total volume. It was then separated into anterior, lateral, and inferior regions corresponding to the adjacent LV segments. Using MRI feature tracking, global longitudinal LV strain (GLS) and peak regional anterior, inferior, and lateral LV strain were quantified. Associations between total EAT and GLS, and between regional EAT and corresponding regional strain were determined by linear regression. Results: Mean total EAT volume was 69.6 ± 29.8 mL and mean GLS was -19.4 ± 2.0%. Individual data points for EAT and longitudinal strain are shown in the figure. Greater total EAT volume was modestly associated with decreased GLS (r2 = 0.127). However, anterior, lateral, and inferior EAT volume did not correlate with a decrease in corresponding regional strain (r2 = 0.003, r2 = 0.088, r2 = 0.016, respectively). Conclusion: In obese adults, total EAT volume was associated with a decrease in global LV systolic function measured by GLS. There was no association between regional EAT depots and corresponding regional LV function to suggest localized metabolic cardiotoxic effect. These preliminary results support our previous findings that EAT has little paracrine effect on cardiac function. Rather, EAT likely represents an additional depot of ectopic fat reflective of a general metabolic abnormality.