Cardiorespiratory effects induced by vagus nerve stimulation in epileptic children.

Vagus nerve stimulation (VNS) is used in pharmaco-resistant epilepsy to decrease the number of seizures. Although it is well known that VNS affects respiration, there are only a few reports concerning an effect of VNS on heart rate or heart rate variability (HRV). We investigated the relationship between respiratory frequency and the high frequency (HF) domain of the discrete Fourier transform (DFT) of the RR interval function during night sleep recordings of ten subjects treated with VNS. Our results show that VNS shifts the frequency of maximal power spectrum density (PSD) in the HF-band, decreases the related PSD and induces a partial cardiorespiratory decoupling.