Transient cardiac asystole during vagus nerve stimulator implantation: A case report

BACKGROUND: Vagal nerve stimulation (VNS) is a Food and Drug Administration approved therapy for seizures with a suggested mechanism of action consisting of cortical desynchronization, facilitated through broad release of inhibitory neurotransmitters in the cortex and brainstem. The vagus nerve contains visceral afferents that transmit sensory signals centrally, from locations that include the heart and the aorta. Although the vagus nerve serves a role in cardiac function, electrical stimulation with VNS has rarely resulted in adverse cardiac events. Here, we report a case of a cardiac event during left-sided VNS implantation. CASE DESCRIPTION: A 22-year-old male with an 8-year history of absence seizures and a 3-year history of medically refractory generalized tonic-clonic seizure was planned for surgical implantation of a VNS device. In the operating room, the patient underwent left-sided VNS implantation. An initial impedance check was performed with subsequent wound irrigation; following a few seconds of irrigation, a 5 s complete cardiac pause was noted. A repeated impedance check, which included turning on the stimulation, did not replicate the cardiac pause. No further pauses or cardiac events were noted and the case continued to completion without issue. The patient was later activated without any further complications. CONCLUSION: This report describes the initiation of a cardiac event, unlikely resulting from VNS, but instead time linked to intraoperative irrigation directly on the vagus nerve.