Those minutes that it takes for emergency medical aid to arrive can make a huge difference in whether the person survives in cases of cardiac arrest. According to the American Red Cross, after a person experiences cardiac arrest, the person’s chance of surviving drops by 7%-10% per minute until treated with defibrillation. They can be bought at several national retailers, and doctors often prescribe them to patients at risk of cardiac arrest. CPR just extends the amount of time a person can be in cardiac arrest and still have this defibrillation work. Good quality CPR and rapid defibrillation together will give the person in cardiac arrest the greatest chance of survival.