Content from the NCSL (National Conference of State Legislators)

Each year, more than 250,000 Americans die from sudden cardiac arrest.  According to medical experts, the key to survival is timely initiation of a “chain of survival”, including CPR (cardiopulmonary resuscitation).  Because of recent technological advances a portable lifesaving device, called an “automated external defibrillator” or “AED” has recently become an important medical tool.  Trained non-medical personnel can use these simplified electronic machines to treat a person in cardiac arrest. The AED device “guides the user through the process by audible or visual prompts without requiring any discretion or judgment.”The American Heart Association notes that at least 20,000 lives could be saved annually by prompt use of AEDs. Ultimately, with broad deployment of AEDs among trained responders, as many as 50,000 deaths due to sudden cardiac arrest could be prevented each year.

2016-17 UPDATES:

Due to recent interest, lists of states requiring placement of AEDs have been updated:

Arkansas Code § 17-95-101 (Good Samaritan Law)

(a) Any health care professional under the laws of the State of Arkansas who in good faith lends emergency care or assistance without compensation at the place of an emergency or accident shall not be liable for any civil damages for acts or omissions performed in good faith so long as any act or omission resulting from the rendering of emergency assistance or services was not grossly negligent or willful misconduct.
(b) Any person who is not a health care professional who is present at an emergency or accident scene and who:
(1) Believes that the life, health, and safety of an injured person or a person who is under imminent threat of danger could be aided by reasonable and accessible emergency procedures under the circumstances existing at the scene thereof; and
(2) Proceeds to lend emergency assistance or service in a manner calculated in good faith to lessen or remove the immediate threat to the life, health, or safety of such a person, shall not be held liable in civil damages in any action in this state for any act or omission resulting from the rendering of emergency assistance or services unless the act or omission was not in good faith and was the result of gross negligence or willful misconduct.
(c) No health care professional who in good faith and without compensation renders voluntary emergency assistance to a participant in a school athletic event or contest at the site thereof or during transportation to a health care facility for an injury suffered in the course of the event or contest shall be liable for any civil damages as a result of any acts or omissions by that health care professional in rendering the emergency care. The immunity granted by this subsection shall not apply in the event of an act or omission constituting gross negligence.
(d) For the purposes of this section, “health care professional” means a licensed physician, chiropractic physician, dentist, optometric physician, podiatric physician, and any other licensed health care professional.