Pacemaker Malfunction Differential Diagnoses

Updated: Jun 21, 2022
  • Author: Priyanka Ghosh, DO; Chief Editor: Jose M Dizon, MD  more...
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Diagnostic Considerations


In pseudomalfunction of the pacemaker, although an apparent pacing system malfunction is suggested clinically, the apparent malfunction is a normal programmed pacer function. This is partly due to new algorithms (eg, Managed Ventricular Pacing [MVP]) [9] to preserve intrinsic conduction and more physiologic pacing.

Examples of pseudomalfunction include the following:

  • Functional undersense with magnet application, safety pacing, triggered mode, fusion and pseudofusion beats, and blanking period

  • Functional oversense with short ventricular blanking period

  • Inappropriate rate with rate hysteresis, rate-drop response, rate smoothing, rate-responsive mode, programmed rest/sleep rate, and mode switch

  • Inappropriate mode with magnet application and mode switch

Manufacturers' advisories

Manufacturer recalls or advisories due to unanticipated device malfunction after their release may require replacement of the pulse generator, lead, or both. A decision analysis model by Amin et al warrants device replacement in pacemaker-dependent patients if a manufacturer advisory device failure rate is over 0.3%. [10]

Differential Diagnoses