Epicardial Adipose Tissue Thickness as Assessed by Echocardiography & Left Ventricular Diastolic Dysfunction

Epicardial adipose tissue (EAT) has been found to be associated with cardiac diseases including coronary artery disease & atrial fibrillation. The relationship of EAT with diastolic function has not been studied well. We evaluated 500 consecutive echocardiograms to calculate maximum EAT thickness (EATmax) in parasternal long axis on 2D echocardiography over the right ventricle in end-systole to quantify EAT. Diastolic function was estimated using transmitral flow & mitral annular tissue doppler in patients with preserved left ventricular function. EATmax & diastolic function was available in 307 patients with preserved LV systolic function (EF>45%). Diastolic function was normal in 67 patients (group 0). 184 patients had grade I diastolic dysfunction (group 1), 47 patients had grade II diastolic dysfunction(group 2) & 9 patients had restrictive/grade III or IV diastolic dysfunction (included in group 2). ANOVA demonstrated significant between the group differences in EATmax. Post hoc test using Bonferroni correction showed significant differences in EATmax between group 0(0.57+0.26 cm) & group 1(0.76+0.26 cm) {p <0.001} &, between group 0 & group 2(0.76+0.24cm){p value<0.001}. There was a significant difference in EATmax between group with normal diastolic function & abnormal diastolic function (p value<0.001). A multivariate logistic regression was performed to assess predictors of abnormal diastolic function using variables of age, gender, EATmax & EF. Only age & EATmax were found to be significant predictors (p value 0.000 & 0.036 respectively; overall model R2= 0.708). In a subgroup analysis including patients in whom complete clinical data was available, the independent predictive significance of EATmax was lost after adding variables such as diabetes mellitus (DM), hypertension(HTN) & body mass index(BMI) to the multivariable regression model. In patients with preserved systolic function, increased quantity of epicardial adipose tissue as assessed by echocardiography predicts abnormal left ventricular diastolic function. However, the independent predictive significance of EATmax is lost after correcting for BMI, DM, HTN & age. Longitudinal studies are required to establish causal association of EAT in pathogenesis of diastolic dysfunction.