Interictal autonomic nervous system function in patients with epilepsy.

We studied 24 patients with partial seizures receiving carbamazepine (CBZ) monotherapy and 40 normal controls, 17 of whom were tested with and without CBZ therapy. Autonomic nervous system assessment included baseline heart rate (HR) and blood pressure (BP); BP and HR changes during orthostasis and cold pressor test (CPT); and HR changes during sinus arrhythmia, Valsalva maneuver, and cold face test with apnea (CFTA). Our study demonstrated normal interictal autonomic function in patients with epilepsy, but, variations in BP and HR during orthostasis and CPT were significantly (p < 0.05) higher in epilepsy patients than in controls with or without CBZ. Epilepsy patients had higher initial increases in BP and greater subsequent decreases in BP than did nonmedicated controls during CPT. Controls with CBZ had higher HR during orthostasis and CFTA than did those without CBZ. CBZ levels correlated with baseline and orthostatic BP and HR during deep breathing (sinus arrhythmia). Our results showed that patients with epilepsy have greater BP and HR variability and reactivity than controls, attributable in part to CBZ levels.