Dr. Peter Libby, chief of cardiovascular medicine at the Brigham and Women’s Hospital in Boston, replies:
Cellphones and portable media players do indeed produce measurable electrical and magnetic fields. But the strength of these fields will not affect ordinary heart rhythm or function, studies suggest. Various studies have also looked at whether cellphones and media players can present a danger to those with an implanted pacemaker, internal defibrillator or similar device. The results, for the most part, have been reassuring. – from NYTimes