The probability of waking up after a cardiac arrest depends on the time of the cardiac arrest, as follows: 1. If the patient has a cardiac arrest within 4 minutes, the probability of waking up after resuscitation is about 40%-50%; 2. Most of the cardiac arrests are caused by the sudden cessation of the ejection function of the heart, and slow or rapid arrhythmias are the main pathological and physiological mechanisms leading to cardiac arrest. After cardiac arrest, the blood supply to the brain is suddenly interrupted, causing the patient to lose consciousness, which may have a chance of survival through timely resuscitation or biological death. Therefore, whether or not a cardiac arrest patient can wake up from a coma is very much related to whether or not timely resuscitation is performed.