The number of malfunctioning pacemakers removed and replaced in patients decreased from 1990 to 2002, while the number for implantable cardioverter defibrillators (ICDs) increased, according to a retrospective review by the US Food and Drug Administration (http://www.fda.gov/cdrh/ocd/icd/). The agency noted that while the reasons for the increased malfunction rate in ICDs have not been determined, they may be due to increased device complexity or more frequent reporting by physicians.
Hampton T. Cardiac Device Safety. JAMA. 2005;294(20):2564. doi:10.1001/jama.294.20.2564-a