Cardiopulmonary resuscitation is crucial when people collapse with cardiac arrest, but it's hard to perform correctly.
High-tech machines that promise to help are already showing up in ambulances and offices. It's not yet proven whether the new technology will improve the 40-year-old resuscitation technique and save lives.
Emergency-care specialists agree CPR today doesn't save as many lives as it could.
Mary Fran Hazinski of the American Heart Association says, "We've got our work cut out for us to make sure CPR is done better."
More than 300,000 Americans each year die of cardiac arrest, where the heart's electrical system goes haywire and the heart abruptly stops beating.
