title: Troubleshooting pacemakers and implantable cardioverter-defibrillators.
abstract: OBJECTIVE
  The purpose of this review is to provide an update on stored diagnostic information furnished by new model pacemakers and implantable cardioverter-defibrillators (ICDs). This information provides crucial information about both device function and arrhythmias discovered with device interrogation and is invaluable when troubleshooting problems with devices.
  
  
  RESULTS
  The most recent generation of pacemakers and ICDs provides extensive diagnostic data regarding both device and lead function. Regular measurements of lead impedance and pacing thresholds allow for early detection of lead insulation break, fracture, dislodgement, or other problems. Analysis of stored intracardiac electrograms (EGMs) alerts the physician to oversensing and undersensing problems, which may manifest as abnormal device function, inappropriate arrhythmia detection, or inappropriate therapy. Simultaneous dual-chamber EGMs help the clinician diagnose the electrophysiologic mechanism of atrial and ventricular tachyarrhythmias, whether they are sustained, nonsustained, symptomatic, or asymptomatic. Detection and specific diagnosis of arrhythmias with EGMs may determine the need for anticoagulation, institution or change of antiarrhythmic drug therapy, or reprogramming of device detection or therapy parameters. Some devices also have the ability to function as patient-activated monitors.
  
  
  CONCLUSIONS
  Better diagnostic data by current pacemakers and ICDs allow for earlier and more accurate identification of device and lead malfunctions as well as better arrhythmia management. In addition, detection of asymptomatic clinically relevant arrhythmias may prompt actions by the physician that can alter clinical outcome.
authors.affiliation: Cardiac Electrophysiology, PinnacleHealth System, Harrisburg, Pennsylvania 17110, USA. dlsmd@comcast.net
authors.forename: David L
authors.initials: DL
authors.lastname: Scher
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000628:therapy; D017147:Defibrillators, Implantable / Q000592:standards / Q000639:trends; D004562:Electrocardiography; D004868:Equipment Failure; D006801:Humans; D010138:Pacemaker, Artificial / Q000592:standards / Q000639:trends