50 Hz oversensing Copy Copy


  • 72-year-old man
  • Ingenio pacemaker (Boston Scientific)
  • ATR episodes recorded in the device memory


  • oversensing of a very fast signal in the atrial channel (viewable at the ventricular channel level but not sensed) saturating the baseline
  • entry counter filled (programmed at 8); duration begins; acceleration of the ventricular pacing rate
  • switch to an asynchronous mode


  • this tracing corresponds to the recording of a 50 Hz source and not to a real atrial arrhythmia
  • it is essential to systematically verify all episodes recorded in the device memory
  • analysis of the EGMs can sometimes correct an erroneous diagnosis concluded by the device
  • the solution in this patient is to identify and eliminate the source of the interference