Cardiac arrest, also called cardiac arrest, is when the heart suddenly stops beating once or twice in a normal rhythm, causing a series of symptoms in patients, such as chest tightness, palpitations, blackness, fainting, shock, or in more serious cases, life-threatening. Therefore, cardiac arrest is very dangerous to health, and the patient’s life is at risk at any time. In case of cardiac arrest, patients need to go to the hospital immediately for treatment. The examination includes electrocardiogram, cardiac ultrasound and color ultrasound Doppler. These tests can clearly identify the original cause of cardiac arrest and provide active treatment in order to achieve the goal of human health.