Epilepsy is associated with alterations in cardiovascular autonomic regulation. The patients did not have any clinical symptoms related to ANS dysfunction, but in cardiovascular reflex tests, cardiovascular dysregulation was detected. Patients with partial as well as idiopathic generalized epilepsies had changes in cardiovascular reflexes. At the group level, the cardiovascular reflexes of patients with untreated, newly diagnosed epilepsy were unaltered. The role of CBZ in contributing to these changes remains controversial.
TLE is associated with cardiovascular dysregulation. Patients with TLE did not complain of any symptoms of dysfunction of the ANS but altered cardiovascular regulation was detected with cardiovascular reflex tests and analysis of HRV. The dynamic measures of HRV were studied for the first time in patients with TLE. Spectral as well as dynamic measures of HRV showed altered pattern of oscillation of HRV in TLE patients. Clinically significant changes in cardiovascular reflex tests were detected in two patients with well controlled TLE and in three patients with refractory TLE, one of whom had hippocampal sclerosis as well.
Altered HRV is present both in patients with refractory and in patients with well controlled TLE. Although the results suggested that these changes are more prominent with severe form of TLE, it seems that TLE itself rather than its severity is important with regard to the observed changes in cardiovascular regulation in patients with TLE. Therefore, both patients with well controlled as well as with refractory TLE can be at risk for sudden cardiac fatalities. Whether the high number of different risk factors in an individual patient with TLE may additionally predispose to fatal dysfunction of the ANS remains unsolved.
The results of the present study did not support an association of structural changes in temporal lobes with particularly altered pattern of HRV. Diminished values of HRV were detected both in patients with and without hippocampal sclerosis. However, the number of patients with hippocampal sclerosis was small, and further studies in larger patient populations are needed to explore the hypothesis that functional imbalance of the ANS in the form of changing biochemical neuromodulation may contribute to cardioregulatory dysfunction in patients with TLE.
Both the cardiovascular reflex tests and analysis of HRV from ambulatory ECG appear to be useful in the assessment of ANS function in patients with TLE. However, their predictive value with regard to increasing the risk of sudden cardiac fatalities in patients with epilepsy remains to be established.