How long does it take before irreversable damage is done when someone has a heart attack?
Brain death starts to occur four to six minutes after someone experiences cardiac arrest if no CPR and/or defibrillation occurs during that time. CPR helps maintain vital blood flow to the heart and brain and increases the amount of time that an electric shock from a defibrillator can be effective. If bystander CPR is not provided, a sudden cardiac arrest victim’s chances of survival fall 7 percent to 10 percent for every minute of delay until defibrillation. Few attempts at resuscitation are successful if CPR and defibrillation are not provided within minutes of collapse. Effective bystander CPR , provided immediately after cardiac arrest, can double a victim’s chance of survival!
