A study done in part at the University of Iowa finds those machines that can jump-start human hearts have a wider ability to heal. Automatic external defibrillators or A-E-Ds are becoming more common in Iowa office buildings, airports, malls and police cars. A-E-Ds were only supposed to be used on people over age eight, but U-of-I pediatrics professor Dianne Atkins says research shows they’re effective on younger children, even infants.Dr. Atkins is senior author of the paper that’ll be published in the May 22nd issue of the journal “Circulation.” She says A-E-Ds can analyze a person’s heartbeat and determine the need for a shock which can normalize the heartbeat and save their life.She says A-E-Ds can be used for detecting types of arrhythmias in children — or irregular or inefficient heartbeats.