Researchers studied the outcomes of more than 14,000 men and women whose hearts stopped suddenly. Those in large crowds like malls, sports stadiums or airports, who were shocked with an automated external defibrillator and then brought to a hospital, had a 34 percent survival rate.
That's compared to an 11 percent survival rate among those who were treated at home with an AED.
Researchers say demographics may explain the difference. Those at home during a cardiac event tend to be older and have more health problems than those who are active and attending major public events.