Pacemaker and defibrillators

Frequent questions and problems in patients with pacemaker and/or defibrillator

Magnet effect


  • Asynchronous mode (delivers stimuli at a fixed rate, independent of any atrial or ventricular activity).
  • Loss of detection of spontaneous electrical activity. Stimulation is blind in VOO or DOO mode.
  • With magnet retrieval initial programmation immediately and automatically restored.
  • Transient loss of rate responsiveness.

Various behaviour with magnet application.

Pacemaker Medtronic

85 bpm, first 3 beats at 100 bpm for threshold control, 65 bpm for ERI (Elective replacement interval) meaning pacemaker signifie que l'appareil doit être remplacé.

Pacemaker St Jude

98.6-100 bpm, progressive diminution up to ERI rate of 85-86 bpm depend on model.

Pacemaker Sorin

96 bpm, progressive diminution up to 80 bpm at ERI.

Pacemaker Boston

100 bpm, 90 bpm then 85 bpm if ERI. 96 bpm, progressive diminution up to 80 bpm at l’ERI.

Pacemaker Biotronik

90 bpm, depend on underlying programmation and depend on battery status. ERI if 80 bpm or 11% of programmed heart rate.


  • No commutation in asynchronous mode.
  • Deactivation of anti-tachycardia therapy.