Many heart specialists and others want to install these simplified, automated devices in airports, shopping malls, casinos, stadiums, schools and even homes to save victims of sudden cardiac arrest, according to an Associated Press report.

Several studies have examined the effectiveness of automated defibrillators when used by trained and designated staff members at casinos and other public places. But in this study, sponsored by the city of Chicago, four-pound defibrillators were distributed like fire extinguishers in labeled glass cabinets at Chicago's O'Hare, Midway and Meigs Field airports. About the size of a toaster, they carried both written and recorded instructions.

During the two-year study, someone tried to use one in each of 18 witnessed cases of fibrillating cardiac arrest. Eleven people were revived. Six of the primary rescuers in the 11 successful efforts were passers-by, largely travelers, with no connection to the program or experience with the machines.

Also, in each case, someone helped by applying cardiopulmonary resuscitation, a manual technique for temporarily restoring some blood flow.

Illinois and many other states have adopted good Samaritan laws, which offer varying protection from lawsuits for well-meaning rescuers. No one was sued during the Chicago airport study. However, one of the 53 defibrillators was stolen.

The study was published Thursday in The New England Journal of Medicine.

Sudden cardiac arrest - from heart attacks, heart disease, accidents or other causes - strikes about 250,000 American adults every year outside hospitals. About 95 percent die before reaching the hospital.

People stand a much better chance of surviving if they undergo defibrillation, which restores a normal beat to a helplessly quivering heart, within the first few minutes of cardiac arrest. Ambulances often fail to arrive with their rescue equipment within ten minutes.

Small, easy-to-operate defibrillators automatically detect the heart's rhythm and decide whether it needs a shock. They typically cost about $2,500 each.