Interictal cardiovascular autonomic responses in patients with temporal lobe epilepsy

PURPOSE: To measure interictal cardiovascular autonomic functions in patients with either refractory or well-controlled temporal lobe epilepsy (TLE). METHODS: For autonomic assessment, heart rate variation during normal and deep breathing, Valsalva maneuver, and tilting were measured in 19 patients with chronic refractory TLE, 19 patients with well-controlled TLE, and 38 age- and sex-matched healthy control subjects. Blood pressure responses to tilting and isometric work also were evaluated. RESULTS: Heart-rate (HR) variation during normal breathing (p = 0.006) and tilting (p = 0.043) was lower in patients with refractory TLE than in control subjects. Heart-rate response to tilting (p = 0.036) was also lower in patients with well-controlled TLE than in control subjects. Blood-pressure responses showed no differences between the patients and the control subjects. Patients taking carbamazepine (CBZ) medication had decreased HR responses to deep breathing (p = 0.046) and to tilting (p = 0.014) compared with the control subjects. CONCLUSIONS: Refractory TLE seems to be associated with dysfunction of the cardiovascular autonomic regulation, manifesting as impaired HR responses to certain stimuli. Interictal autonomic dysfunction is seen in patients with well-controlled TLE as well, but it may be more evident in patients with refractory epilepsy. CBZ medication may also be associated with altered autonomic cardiac control.