EurekAlert -- David Callans, MD, a professor of cardiovascular medicine at the University of Pennsylvania School of Medicine, will be available to comment on the New England Journal of Medicine study on the use of automated external defibrillators (AEDs) for sudden cardiac arrests that occur in the home. Callans, author of the journal editorial that accompanies the new study, serves as associate director of electrophysiology for the Penn Health System, and has extensive experience in studying ventricular arrhythmias.