The majority of deaths yearly in the United States (approximately 1 million) are the result of cardiovascular disease. Many of these deaths occur because of sudden and unexpected disturbances of the normal heart rhythm that result in ineffective pumping of the blood to the brain and other vital organs. Cardiac arrest from these life-threatening disturbances of the heart rhythm is a leading cause of disability and a major source of healthcare costs in the United States. It is estimated that more than 350 000 cases of cardiac arrest occur annually in this country.
Cardiac arrest is usually caused by a disturbance of the cardiac rhythm called “ventricular fibrillation,” wherein the left chamber of the heart develops a very rapid rhythm that prevents blood from pumping out to the body and that is incompatible with life. Immediate therapy with defibrillation is the only effective treatment. Defibrillation involves delivering a shock to the chest wall through adhesive pads or paddles to reestablish a normal cardiac rhythm. Although standard defibrillators must be operated by trained medical personnel, automated external defibrillators (AEDs) are now available for use by trained medical and minimally trained lay personnel. Using AEDs can result in more cases of survival from cardiac arrest.