What is a runaway pacemaker?

Updated: Oct 11, 2019
  • Author: Daniel M Beyerbach, MD, PhD; Chief Editor: Jeffrey N Rottman, MD  more...
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A malfunction of the pacemaker generator resulting in a life-threatening rapid tachycardia (up to 200 beats per minute [bpm]) is known as runaway pacemaker. The generator may malfunction from various causes, although most commonly it is a battery failure or external damage.

This rare medical emergency requires immediate action. An external magnet may induce slower pacing, but it is possible that the device will not respond to magnet application and more aggressive measures may be necessary. If a patient becomes unstable, treatment involves making an incision in the chest wall over the pacemaker and severing the pacemaker leads from the generator. Note that the patient may require temporary pacing as a result.

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