Heart‐rate variability indices as predictors of the response to vagus nerve stimulation in patients with drug‐resistant epilepsy

• Published in: Epilepsia (Copenhagen) Vol. 58; no. 6; pp. 1015 - 1022
• Main Authors: Liu, Hongyun, Yang, Zhao, Huang, Lei, Qu, Wei, Hao, Hongwei, Li, Luming
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.06.2017
• Subjects: Adolescent; Adult; Antiepileptic drug; Autonomic nervous system; Autonomic Nervous System - physiopathology; Child; Drug resistance; Drug Resistant Epilepsy - physiopathology; Drug Resistant Epilepsy - therapy; Drug‐resistant epilepsy; EKG; Electrocardiography; Electrocardiography, Ambulatory; Electrodes, Implanted; Epilepsy; Female; Heart diseases; Heart rate; Heart Rate - physiology; Heart‐rate variability; Humans; Male; Nonlinear Dynamics; Parasympathetic nervous system; Seizures; Sex; Signal Processing, Computer-Assisted; Treatment Outcome; Vagus nerve; Vagus Nerve Stimulation; Xenografts; Young Adult; Antiepileptic drug; Vagus nerve stimulation; Drug-resistant epilepsy; Autonomic nervous system; Heart-rate variability
• ISSN: 0013-9580; 1528-1167; 1528-1167
• DOI: 10.1111/epi.13738

Summary Objective To assess heart‐rate variability (HRV) measures of interictal electrocardiography (ECG) for drug‐resistant epilepsy and to relate the findings to the outcome of vagus nerve stimulation (VNS) treatment. Methods Time‐domain, frequency‐domain, and nonlinear analyses were used to analyze preoperative HRV measures in 32 patients with drug‐resistant epilepsy who had received VNS implants at the same hospital and 32 healthy age‐ and sex‐matched control subjects. HRV measurements based on ambulatory 24 h ECG recordings were analyzed to identify seizure reduction 1 year after VNS treatment. Responders were defined as having at least 50% seizure reduction 1 year after treatment. Results Patients with drug‐resistant epilepsy had significantly lower time domain (SDNN, RMSSD, pNN50), frequency domain (VLF, LF, HF, TP), and nonlinear (SD1, SD2) HRV measurements than matched healthy controls. None of the analyzed HRV measures of the responders differed significantly from their controls, whereas those of the nonresponders had significantly lower RMSSD, pNN50, HF, and SD1 than the responders. Significance The preoperative HRV indices demonstrate that nonresponders have more pronounced impairment of their cardiac autonomic function than the responders. Presurgical HRV measurements representing parasympathetic cardiac control or vagal tone were significantly associated with the responsiveness to VNS. Thus the measurements show promise for predicting the reduction of seizure frequency after VNS treatment.