PURPOSE Many patients with epilepsy are unable to completely control seizures with medication alone. Vagus nerve stimulation is an effective nonpharmacologic option for treatment-resistant epilepsy. AutoStim technology is a relatively new VNS feature that provides extra stimulations in response to tachycardia, which often precedes seizures. This feature adds a currently unknown number of extra stimulations per day. This study aims to evaluate that actual stimulations' patients receive per day as a function of varying VNS settings. METHODS This project was a retrospective chart review. All patients with implanted VNS devices with AutoStim technology managed at Northwestern's epilepsy clinic were included in the study. Data were collected on duty cycle, tachycardia threshold, expected number of stimulations per day, normal mode stimulations per day, and AutoStims per day. Associations between all variables were evaluated. RESULTS Sixty-seven patients with VNS stimulators met inclusion criteria leading to 305 unique VNS interrogation results. This study demonstrated the smallest number of extra stimulations between tachycardia thresholds of 40 and 60 with absolute minimums at 35 and 45. Our results also demonstrate a trend of decreasing extra stimulations per day with increased duty cycle at each tachycardia threshold evaluated. CONCLUSIONS These data demonstrate the effect of duty cycle and tachycardia threshold on extra stimulations per day and demonstrated the optimal settings for reducing extra stimulations. This research provides reassurance and information to patients and providers about the actual number of stimulations patients receive with AutoStim technology.

中文翻译：

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心反应性迷走神经刺激中占空比、心动过速阈值与自刺激传递之间的关系

目的 许多癫痫患者仅靠药物无法完全控制癫痫发作。迷走神经刺激是治疗难治性癫痫的有效非药物选择。AutoStim 技术是一种相对较新的 VNS 功能，它提供额外的刺激来应对经常在癫痫发作之前发生的心动过速。此功能每天添加当前未知数量的额外刺激。本研究旨在评估患者每天接受的实际刺激作为不同 VNS 设置的函数。方法 该项目是一项回顾性图表审查。所有在 Northwestern 癫痫诊所管理的具有 AutoStim 技术的植入式 VNS 设备的患者都包括在该研究中。收集有关占空比、心动过速阈值、每天的预期刺激次数、每天正常模式刺激，每天 AutoStims。评估了所有变量之间的关联。结果 67 名使用 VNS 刺激器的患者符合纳入标准，产生了 305 个独特的 VNS 询问结果。该研究表明，心动过速阈值 40 和 60 之间的额外刺激次数最少，绝对最小值为 35 和 45。我们的结果还表明，随着每个评估的心动过速阈值的占空比增加，每天额外刺激减少的趋势。结论 这些数据证明了占空比和心动过速阈值对每天额外刺激的影响，并证明了减少额外刺激的最佳设置。