For years, many people had thought that there was a risk of mobile phone signals interfering with pacemakers - and, at times, have even warned those who have pacemakers installed to stay away from mobile phones (as if that's possible, these days). Now, a study has come out saying that, indeed, some pacemakers get confused by some signals from GSM phones. They say this isn't a problem if the pacemaker has a ceramic filter (most new ones do), and suggest that all new pacemakers use a ceramic filter. It's unclear from the article how big a problem this really is, or what the likelihood of interference really is.