Original Research ARTICLE
Post-ictal Modulation of Baroreflex Sensitivity in Patients with Intractable Epilepsy
- 1Neurology, Columbia University Medical Center, United States
- 2Electrical Engineering and Computer Science, Case Western Reserve University, United States
- 3Neurology, University Hospitals Cleveland Medical Center, United States
OBJECTIVE: Seizure-related autonomic dysregulation occurs in epilepsy patients and may contribute to Sudden Unexpected Death in Epilepsy (SUDEP). We tested how different types of seizures affect baroreflex sensitivity (BRS) and heart rate variability (HRV). We hypothesized that BRS and HRV would be reduced after bilateral convulsive seizures (BCS). METHODS: We recorded blood pressure (BP), electrocardiogram (ECG) and oxygen saturation continuously in patients (n=18) with intractable epilepsy undergoing video-EEG monitoring. A total of 23 seizures, either focal seizures (FS, n=14) or BCS (n=9), were analyzed from these patients. We used 5 different HRV measurements in both the time and frequency domains to study HRV in pre- and post-ictal states. We used the average frequency domain gain, computed as the average of the magnitude ratio between the systolic BP (BPsys) and the RR-interval time series, in the low-frequency (LF) band as frequency domain index of BRS in addition to the instantaneous slope between systolic BP and RR-interval satisfying spontaneous BRS criteria as a time domain index of BRS. RESULTS: Overall, the post-ictal modulation of HRV varied across the subjects but not specifically by the type of seizures. Comparing pre- to post-ictal epochs, the LF power of BRS decreased in 8 of 9 seizures for patients with BCS; whereas following 12 of 14 FS, BRS increased. Similarly, spontaneous BRS decreased following 7 of 9 BCS. The presence or absence of oxygen desaturation was not consistent with the changes in BRS following seizures, and the HRV does not appear to be correlated with the BRS changes. These data suggest that a transient decrease in BRS and temporary loss of cardiovascular homeostatic control can follow BCS but is unlikely following FS. SIGNIFICANCE: These findings indicate significant post-ictal autonomic dysregulation in patients with epilepsy following BCS. Further, reduced BRS following BCS, if confirmed in future studies on SUDEP cases, may indicate one quantifiable risk marker of SUDEP.
Keywords: epilepsy; autonomic nervous system; baroreflex function; baroreflex sensitivity;
heart rate variability; SUDEP
Keywords: Epilepsy, Autonomic Nervous System, baroreflex function, baroreflex sensitivity, Heart rate variability, SUDEP
Received: 31 Jan 2018;
Accepted: 03 Sep 2018.
Edited by:Mark J. Cook, The University of Melbourne, Australia
Reviewed by:Luiz Eduardo Betting, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Brazil
Marino M. Bianchin, Universidade Federal do Rio Grande do Sul (UFRGS), Brazil
Copyright: © 2018 Esmaeili, Kaffashi, Theeranaew, Dabir, Lhatoo and Loparo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Behnaz Esmaeili, Columbia University Medical Center, Neurology, New York, 10032, NY, United States, firstname.lastname@example.org