When is Likelihood of brain damage and typical timing after heart stopping?

The likelihood of brain damage increases significantly within minutes after the heart stops, as the brain is highly sensitive to a lack of oxygen. Typically, irreversible brain damage can occur within 4 to 6 minutes of cardiac arrest, although some brain cells may begin to die within just a few minutes. Prompt cardiopulmonary resuscitation (CPR) and defibrillation are critical to prolonging brain viability and minimizing damage. After about 10 minutes without oxygen, the chances of survival with intact brain function diminish greatly.