HEART PERIOD VARIABILITY DURING VAGAL NERVE-STIMULATION

Vagal nerve stimulation is an emerging therapy for epilepsy, yet littl e is known regarding the effects of this stimulation on heart period v ariability. We selected 10 patients (two female, eight male) who were receiving high-frequency, high-intensity left vagal nerve stimulation for intractable epilepsy. Electrocardiogram data were recorded for a 7 min baseline, 2.5 min of stimulation and a 7 min post-stimulation per iod. We found no significant changes in average heart period, instanta neous changes of successive R-to-R intervals greater than 50 ms or fra ctal dimension. We also found no significant changes in the total powe r in the 0.0-0.04 Hz, 0.04-0.12 Hz and 0.2-0.4 Hz bands with stimulati on of the left vagus nerve. This study suggests that left vagal nerve stimulation has little acute effect on the cardiac rhythm or heart per iod variability.