Echocardiography is the most common tool used in cardiology to show the structure of the heart chambers, ventricular wall motion and hemodynamics, and it is inexpensive, non-invasive and suitable for all people. In clinical work, we often encounter abnormal diastolic function written on the cardiac ultrasound report, does it mean heart failure or coronary artery disease? Many patients come to the clinic with this question. Ventricular diastole includes both ventricular relaxation and ventricular compliance. Determinants of diastolic function include age, filling pressures, myocardial stiffness, and early diastolic abnormalities. Epidemiological surveys have found that left ventricular diastolic dysfunction is higher than systolic dysfunction in community populations and increases with age, due to physiological degenerative lesions such as thickening of myocardial fibers and increased type II collagen content with increasing age. In addition, hypertension, left ventricular hypertrophy, diabetes mellitus, hyperinsulinemia and coronary artery disease are all independent risk factors for abnormal diastolic function. Some specific types of heart disease such as restrictive cardiomyopathy are due to infiltration of abnormal interstitial material that affects the diastolic function of the heart. The spectrum of mitral orifice flow velocity on cardiac ultrasound is a bimodal pattern: peak E and peak A. Peak E is the filling peak caused by active dilatation of the left ventricle, and peak A is the filling peak that occurs during contraction of the left atrium; peak E > peak A in normal left ventricular diastolic function and peak E in impaired diastolic function.