Since its FDA approval in 1997, Vagal Nerve Stimulation has become an important therapeutic option in drug-resistant epilepsy. VNS is considered an effective and safe therapy with low rates of complications. Bradycardia and asystole have been reported in the literature with an estimated incidence of 0.1%, primarily during the intraoperative period. Asystole related to VNS is a rare complication, with only few reported cases. There has only been one other reported case where routine replacement of a VNS generator led to asystole.

Cardiac monitoring showed asystole corresponding with the VNS Cycles. The device was turned off and cardiology consultation was obtained. Patient was monitored in the ICU while VNS was turned on at significantly lower settings. Patients Settings before generator replacement: Output current 2.5mA, Magnet Current 2.75mA, Frequency 25Hz, Pulse Width 250ms, On-Time 30 Seconds, Off Time 1.8 minutes. Patient’s new settings after asystolic episodes: Output current 0.25mA, Magnet Current 0.375mA, Frequency 25Hz, Pulse Width 250ms, On-Time 30 Seconds, Off Time 1.8 minutes. The patient tolerated the new settings without further asystolic episodes.

Although serious adverse events are rare, bradycardia and asystole can occur during the intraoperative period primarily during initial placement of the leads. Rarely it can happen after the initial placement. Our objective is to increase physician awareness of this rare but potentially fatal complication and to share the clinical approach that was utilized. We recommend device setting adjustments and close cardiac monitoring with cardiology consultation in these cases.