An ECG study of individuals receiving vagus nerve stimulation (VNS) for drug-resistant focal epilepsy has demonstrated that VNS induces favourable changes in T-wave alternans, possibly reflecting improved balance between sympathetic and parasympathetic activity. T-wave alternans is an established noninvasive marker for risk of sudden cardiac death; the study finding, therefore, suggests that VNS reduces the risk of sudden unexpected death in epilepsy (SUDEP).