If someone you love suddenly went into cardiac arrest and stopped breathing, would you know what to do? Many Americans die each year from sudden cardiac arrest, but with the right tools and citizen training, thousands could survive.

During sudden cardiac arrest, the heart muscle ceases pumping and quivers, a condition called ventricular fibrillation. A small percentage of patients who suffer a sudden cardiac arrest outside of the hospital survive.

While celebrating her 48th birthday, New York nurse Julie Lycksell suddenly collapsed and stopped breathing. Her friend asked someone to call 911, while her husband and a restaurant patron started cardiopulmonary resuscitation (CPR), and within a minute or two a policeman trained in using an automated external defibrillator (AED) arrived and administered life-saving pulses of electricity. Unlike most sudden cardiac arrest victims, Lycksell had no history of heart trouble, and doctors could not determine why she developed an abnormal heart rhythm.

"The doctor told me it was just a strange thing that happened to me," Lycksell says. "If the policeman hadn't had a defibrillator, I'd be dead."

Rapid initiation of the American Heart Association's chain of survival can save the lives of people who experience sudden cardiac arrest.

Here's what to do:

• Recognize that there is an emergency. If the person is unresponsive, emergency care should be started.
• Call 911 or have someone else call.
• If there is an AED available, get it (or have someone else get it) and follow the steps on the machine.
• Start CPR by giving chest compressions. Push in the chest at least two inches at a fast rate of at least 100 compressions per minute.
• If you are trained in CPR, after 30 compressions, open the person's airway and give two rescue breaths. Then, continue with the chest compressions. If you feel more comfortable, you can give the compressions without the breaths until the ambulance arrives.

The American Heart Association conducts classes to teach lay people how to administer CPR. International bystander-CPR advocate Mickey S. Eisenberg, MD, PhD, director of the University of Washington Medical Center's emergency medicine service, studied young people and adults older than 60 and found that they are able to learn the life-saving skill online and then successfully perform CPR on a mannequin.

Early defibrillation plays a key role in improving the odds someone will survive sudden cardiac arrest without brain damage. The American Heart Association's emergency care guidelines place a stronger emphasis on early defibrillation and improved access to AEDs. Heartsaver AED CPR classes include information about how to use the devices.

Two studies published in The New England Journal of Medicine report unprecedented survival rates of 53% after trained casino security guards administered CPR and AED, and 40% after airline flight attendants did the same. University of Arizona researchers reported that the high success rate at the casinos depended on no more than three minutes elapsing between time of collapse and defibrillation.

Prior studies have shown improved survival rates in communities where trained police officers, often the first on the scene of an emergency, carry defibrillators. Dr. Eisenberg believes many lives would be saved if a defibrillator was nearby and family members knew how to use it.

Dr. Eisenberg's research has shown that older adults can correctly use AEDs after watching a short video. Another University of Washington study showed that sixth-grade students could accurately place and activate the devices during a training session.

AEDs are found in airports, shopping malls, casinos, community centers, and sports or medical facilities. AEDs can be somewhat costly and are available over the counter, without prescription. If you purchase an AED, be sure to get proper training on how to safely use it.