Sudden cardiac arrest (SCA) is a leading cause
of death in the United States, striking more than 350,000 individuals each year.
Sudden cardiac arrest can happen anywhere, to anyone, at any time - without warning,
without symptoms, and regardless of age or general health. People who suffer sudden
cardiac arrest usually do not know in advance that they are vulnerable to this fatal
SCA is most often caused by ventricular fibrillation
(VF), an irregular, quivering heart rhythm. The victim stops breathing, and no pulse
is present. Defibrillation, an electric shock to the heart, is the only effective
treatment for VF, stopping the chaotic activity and allowing a coordinated heart
rhythm to resume. SCA can be caused by electrical shock, allergic reaction, drug
overdose, suffocation, drowning, heart attack (myocardial infarction), or, in many
cases, for no apparent reason.
Defibrillation is the delivery of a specific
electrical shock to the heart. This shock stops the uncoordinated electrical activity
of the heart, and allows the return of the heart's regular rhythm and pulse. Defibrillation
is the only definitive treatment for sudden cardiac arrest, and time is very critical.
Surviving SCA is largely dependent on how quickly the patient is defibrillated.
For each minute that defibrillation is delayed, the victim's chance of survival
decreases by seven to ten percent. The patient suffers irreversible brain damage
within 4 to 6 minutes after cardiac arrest. After 10 minutes, few victims of SCA
survive. The American Heart Association estimates that an additional 50,000 lives
could be saved each year with widespread access to defibrillators.
Over the last 10 years, advances in technology
and design have made defibrillators easy to operate for people with little training.
Modern automated external defibrillators (AEDs) are safe, easy to use, effective,
and reliable. The defibrillator will only permit a shock to be delivered if a specific,
irregular heart rhythm is detected. It will not allow a shock to be delivered if
one is not needed. No longer must one sit and wait for help to arrive as precious
seconds pass. No longer must one rely on CPR, which can buy time for a sudden cardiac
arrest victim, but alone cannot save a life.
AEDs are simple to use, and designed for rescuers
with minimal training. Simple voice and/or text instructions guide the rescuer through
AEDs are designed to permit a shock to be delivered
only when needed. The AED quickly analyzes the victim's heart rhythm through adhesive
pads placed on the chest and only allows a shock to be delivered when a shockable
rhythm is present.