Measuring vagal activity in postictal bradycardia.

Alterations to cardiac electrical conduction are some of the most frequently observed systemic complications of seizures, with autonomic dysregulation cited as the principal driver for these alterations. In this prospective study, we use 6-lead continuous ECG monitoring in hospitalized patients with epilepsy to trend heart rate patterns in the postictal period. A total of 117 seizures in 45 patients met the criteria for analysis. There was a postictal heart rate increase of 61% (n = 72 seizures), and a decline in heart rate (deceleration) following 38.5% (n = 45). Using 6-lead ECGs for waveform analysis revealed that there was PR prolongation accompanying those seizures that were associated with postictal bradycardia.

Synergistic effect of sleep depth and seizures correlates with postictal heart rate.

Our objective was to determine the effect of sleep on heart rate following a recorded seizure. We prospectively acquired heart rate data in hospitalized epilepsy monitoring unit patients. We analyzed heart rate trends for multiple seizures (n = 101) in patients (n = 42) with electroencephalographically confirmed events. The patient's sleep state was scored for the 5 min preceding each seizure and correlated with the postictal nadir heart rate (PINHR). The depth of sleep during the 5 min before a seizure correlated (correlation coefficient [CC] = -.229, p < .05) with PINHR. This result was more significant and strengthened (CC = -.272, 95% confidence interval = -.392 to -.152, p < .001) when adjusted for covariates of age, generalized tonic-clonic seizures, and baseline heart rate. Sleep depth is an independent predictor of the change in heart rate following a seizure. Diminished heart rate following a seizure in the setting of sleep is likely secondary to non-rapid eye movement sleep's synergistic effect on parasympathetic tone.