Suddenly waking up from a cardiac arrest during sleep may be caused by premature beats, serious heart disease, or over-exertion. 1. Premature beats: Premature beats are heart beats caused by premature impulses from an ectopic pacing point, and are the most common cardiac arrhythmia. When a premature beat occurs, due to the unexpected contraction of the heart, the heart beat can be clearly felt, and then there is a period of pause after the premature beat, so there can be a feeling of cardiac arrest. It is recommended that the patient go to the hospital to improve the 24-hour dynamic electrocardiogram to clarify the cause of the disease. 2. Serious heart disease: myocardial infarction, coronary heart disease, cardiovascular blockage can lead to sudden cardiac arrest, and hereditary heart disease can also lead to sudden cardiac arrest. It is recommended that patients go to the hospital to improve cardiac enzymes, electrocardiogram, cardiac ultrasound, chest CT and other tests to clarify the diagnosis. 3. Excessive exertion: Staying up late and working hard, long-term fatigue, overuse of the brain, emotional excitement, nervous tension, etc. can cause hallucinations similar to sudden cardiac arrest. It is recommended that patients go to the hospital for dynamic electrocardiogram or ordinary electrocardiogram. It is recommended that patients go to regular hospitals to avoid delays in diagnosis and treatment.