Case report of patient with bradycardia as a complication of VNS therapy and psychiatric worsening after turning VNS off

Abstract

Despite available pharmacological treatment methods, about 25-40% of patients suffer from pharmacoresistant epilepsy. Such patients are candidates for surgery, that is, classic resectable or minimally invasive neurosurgical treatment. Vagal nerve stimulator (VNS) as minimally invasive neurosurgical treatment is indicated for the adjuvant and palliative treatment of pharmacoresistant epilepsy [1]. The side effects of VNS are mostly transient and mild, such as paraesthesia, cough, dyspnoea, pharyngitis, hoarseness, alteration of voice, neck pain, and swallowing disorders, while laryngeal muscle spasm and obstruction of upper airways occur less frequently, as well as worsening of sleep apnoea. Bradycardia, atrioventricular block, and asystole, as the most severe side effects, are very rare [2]. In 2005 VNS was approved for the adjunctive long-term treatment of chronic or recurrent depression in adult patients experiencing a major depressive episode who had failed to respond to four or more adequate antidepressant treatments. However, the efficacy of VNS for treating depression remains unclear [3].

Cardiovascular comorbidities in epileptology

“…In pharmacoresistant patients, vagus nerve stimulation (VNS) presents a frequently used therapeutic method that has documented success in seizure reduction, although its exact mechanism of action is still unknown (36). VNS-induced cardiovascular complications have rarely been reported (37,38,39). Conversely, the current state of knowledge suggests that VNS exhibits a significant cardioprotective effect by two separate mechanisms: affecting the central nervous system leading to seizure reduction, and direct influence on the heart leading to a decrease in its electrical instability (40).…”

Externalization of an infected vagus nerve stimulator generator without a break in anti-seizure therapy: a technical note

“…[1] Often there is an observation period to ensure complete removal of the infection before a new VNS device can be implanted, resulting in an interruption in VNS therapy for weeks or even months [4], leaving the patient vulnerable to an increase in seizure frequency. [4][5][6] We report a case of VNS pocket infection successfully managed with generator externalization leaving the device therapeutically intact. This allowed uninterrupted VNS therapy during infection treatment as well as short-interval replacement of the generator and leads.…”