Bradycardia and asystole with the use of vagus nerve stimulation for the treatment of epilepsy: a rare complication of intraoperative device testing

Epilepsia. 1999 Oct;40(10):1452-4. doi: 10.1111/j.1528-1157.1999.tb02019.x.


Purposes: A 56-year-old man with mild mental retardation, right congenital hemiparesis, and refractory partial seizures was referred for vagus nerve stimulation (VNS).

Methods: Routine lead diagnostic testing during the surgical procedure (1.0 mA, 20 Hz, and 500 micros, for approximately 17 s) resulted, during the initial two stimulations, in a bradycardia of approximately 30 beats/min. A third attempt led to transient asystole that required atropine and brief cardiopulmonary resuscitation.

Results: The procedure was immediately terminated, the device removed, and the patient recovered completely. A postoperative cardiologic evaluation, including an ECG, 24-h Holter monitor, echocardiogram, and a tilt-table test, was normal.

Conclusions: Possible mechanisms for the bradycardia/asystole include stimulation of cervical cardiac branches of the vagus nerve either by collateral current spread or directly by inadvertent placement of the electrodes on one of these branches; improper plugging of the electrodes into the pulse generator, resulting in erratic varying intensity of stimulation; reverse polarity; and idiosyncratic-type reaction in a hypersusceptible individual. The manufacturer reports the occurrence rate in approximately 3,500 implants for this intraoperative event to be approximately one in 875 cases or 0.1%.

Publication types

  • Case Reports

MeSH terms

  • Bradycardia / etiology*
  • Electric Stimulation Therapy / adverse effects*
  • Electric Stimulation Therapy / instrumentation*
  • Epilepsy / surgery*
  • Epilepsy, Complex Partial / surgery
  • Equipment Failure
  • Heart Arrest / etiology*
  • Humans
  • Intraoperative Complications / etiology*
  • Male
  • Middle Aged
  • Vagus Nerve / physiology*