Heart rate variability in patients with frontal lobe epilepsy

OBJECTIVE To identify autonomic dysregulation in frontal lobe epilepsy (FLE). METHODS We studied 14 male and 11 female subjects with FLE and an equal number of matched healthy control subjects. Lead I electrocardiograms were obtained for 5 min in the interictal state during daytime. Frequency-domain analysis of heart rate variability was performed and the data subsequently converted to heart rate interval and high frequency (HF; 0.15-0.45 Hz) power which representing vagal or parasympathetic regulation, as well as low frequency (LF; 0.04-0.15 Hz) power and LF/(HF+LF) expressed in normalized units (LF%) (considered to mirror sympathetic regulation). Differences in data between groups were compared using t-test. RESULTS The epilepsy group had a lower mean heart rate interval and a lower high frequency power. CONCLUSIONS Patients with FLE have interictally faster heart rates, attributed to lower parasympathetic drive, which may contribute to the higher incidence of sudden death that is seen in this group of patients. This suggests that the mechanism of decreased HRV in patients with FLE is probably different from that in patients with temporal lobe epilepsy.