Echocardiographic Epicardial Fat: A Review of Research and Clinical Applications

Echocardiographic epicardial fat thickness. Epicardial fat thickness (within red dashed shape) is identified as the echo-free space between the outer wall of the myocardium and the visceral layer of pericardium in the parasternal long-axis view. Epicardial fat thickness is measured during end-systole at the point on the free wall of the right ventricle along the midline of the ultrasound beam, with the best effort to be perpendicular to the aortic annulus, used as an anatomic landmark.

Epicardial versus pericardial fat thickness. Pericardial fat (within yellow arrows and yellow dashed shape) can be identified as the hypoechoic space anterior to the epicardial fat (within red arrows and red dashed shape). Pericardial fat usually does not deform substantially with cardiac cycles and does not appear as hyperechoic space. Modified parasternal long-axis view.

Large echocardiographic epicardial fat thickness. Large epicardial fat thickness (within red arrows and red dashed shape) when measured just to the right of the aortic annular plane may abruptly increase in size. This abrupt increase in end-systolic epicardial fat thickness is due to the steep downward turn of the free wall of the right ventricle as it approaches the proximal ascending aorta. In these cases, it is recommended to measure the largest epicardial fat thickness to the left of the annular plane.