Cardiac function refers to the pumping function of the heart. If we compare the human body to a machine, the heart is the engine, and the engine keeps pumping blood to the periphery every moment to complete the circulation. Especially the EF value, which is the reflection of the heart’s pumping function. Under normal circumstances, an EF value of more than 50% indicates that the heart can pump 50% of the blood outside the heart with each beat. If the EF value is below 50%, consider cardiac insufficiency or decreased cardiac function and perfect further examination to find out the cause of the decreased cardiac function.