We aimed to investigate associations between pre-to-post-ictal BRS changes with hemodynamic patterns during stimulation-induced seizures (SIS).

Ictal cardiovascular autonomic dysfunction (CAD) is widely recognized, but may present with a variety of hemodynamic types. Disruption of central autonomic control, specifically arterial baroreflex sensitivity (BRS) dysfunction, may be more profound during a distinct combinations of heart rate (HR) and blood pressure (BP) changes.

We analyzed HR and beat-to-beat BP data from 35 patients (median age with interquartile range 30 years [25-39 years], 22 women) with drug resistant focal epilepsy undergoing stereo-EEG (SEEG) monitoring with electrical stimulation. Ictal CAD was defined as newly appeared hypertension (systolic or diastolic BP ≥140/90 mmHg), hypotension (systolic or diastolic BP <90/60 mmHg), tachycardia (HR >100 bpm), and bradycardia (HR <60 bpm) during the first minute of seizures if changes of HR/BP exceeded 3 standard deviation thresholds from prestimulation baseline mean values. Hemodynamic patterns were categorized based on constellations of HR and BP changes. BRS was assessed during 1-minute preictal and ictal periods. Wilcoxon signed-rank test was used to compare pre-to-post-ictal changes of BRS (p < 0.05).

We registered 54 SIS, 20 of them revealed three hemodynamic patterns. Pattern 1 (n=5): ictal hypotension – bradycardia; Pattern 2 (n=5) ictal hypotension – tachycardia; Pattern 3 (n=10) hypertension – tachycardia. We did not reveal significant pre-to-post-ictal changes of BRS for Pattern 1 (p=0,3) and Pattern 2 (p=0,06). Significant decrease of BRS values was found in SIS manifesting with Pattern 3 (p=0,002).

Our findings demonstrate diverse ictal hemodynamic patterns during SIS. Significant blunting of BRS was associated with the ictal hypertension-tachycardia pattern and reflected transient impairment of central autonomic regulation during stimulation-induced seizures.