5.2. Cardiovascular reflex tests (Studies I-II and IV)

The main results of the Study I are presented in Tables 9 and 10. The mean HR and BP responses in patients with untreated recently diagnosed epilepsy did not differ from those of the control subjects. The SD of RR intervals (p < 0.05) and the maximum systolic BP increase in isometric work (p < 0.05) were diminished in patients who had been treated with AEDs for epilepsy for a long time. The diminished max-min ratio (p < 0.05), Valsalva ratio (p < 0.001) and BP responses during isometric work (p < 0.001) were noted only in patients treated with CBZ. In relation to the type of epilepsy, the patients with idiopathic generalized epilepsies had diminished SD of RR interval (p < 0.05), whereas patients with partial epilepsies had diminished BP responses during isometric work (p < 0.05).

Two (5.4%) patients with recently diagnosed untreated partial epilepsies had two measurements of cardiovascular reflexes outside the reference range obtained in our control subjects (mean ± 2 SD). One had diminished SD of RR interval and Valsalva ratio, and the other had abnormal BP responses 2 and 7 min after tilting (30:15 ratio). One patient (2.1%) receiving long-term monotherapy (CBZ) for partial epilepsy had two tests (max-min ratio and Valsalva ratio) outside the normal range. None of the control subjects had two or more abnormal test.

In Study II the SD of RR interval (p < 0.001) and 30:15 ratio (p < 0.05) were lower in patients with refractory TLE than in the control subjects. The 30:15 ratio (p < 0.05) was also diminished in patients with well controlled TLE compared to the control subjects. Patients with refractory TLE had lower SD of RR interval compared to the patients with well controlled TLE (p < 0.05). The BP responses (to tilting and isometric work) showed no differences between the patients and the control subjects (Table 11).

A decreased max-min ratio was found in patients taking CBZ as either monotherapy or polytherapy, compared to the control subjects (patients 1.26 0.03, control subjects 1.37 0.03, p < 0.01). They also had lower 30:15 ratio than the control subjects (1.10 0.02 versus 1.21 0.02 respectively, p < 0.01). The patients taking CBZ only as monotherapy showed a trend to the lower SD of the RR interval (31.13 ± 6.90 versus 46.25 ± 5.67 respectively, p = 0.127), the max-min ratio (1.39 ± 0.03 versus 1.30 ± 0.05 respectively, p = 0.217), the Valsalva ratio (2.16 ± 0.09 versus 1.91 ± 0.20 respectively, p = 0.217), and the 30:15 ratio (1.19 ± 0.03 versus 1.13 ± 0.04 respectively, p = 0.207) (Table 11).

The values of the measured parameters did not differ between patients taking other AEDs as monotherapy or polytherapy and the control subjects, or between patients taking different AED regimens, lateralization of epileptic focus, or interictal EEG findings.

Three patients with refractory TLE (15.8%) and two patients with well controlled TLE (10.5%) had two values of the measurements of cardiovascular responses below the reference range obtained in our control subjects (mean 2 SD). These patients did not show any characteristic pattern of antiepileptic medication, drug dosage or serum concentration, type or frequency of seizures, duration of TLE or lateralization of epileptic focus in EEG-registration compared to the patients with cardiovascular responses within normal range. However, four out of five patients with clinically significant abnormalities of cardiovascular reflexes were men.

In Study IV, the SD of the RR interval (p < 0.05), the max-min ratio (p < 0.05) and the 30:15 ratio (p < 0.001) of the HR responses were lower in the patients with TLE than in the control subjects. In patients with hippocampal sclerosis, the mean values of most of the parameters of the cardiovascular reflex tests were smaller than those of the patients without hippocampal sclerosis. However, the differences did not reach statistical significance (Table 12).

One patient with (12.5%) and three patients without (9.7%) HS had two values of the measurements of cardiovascular reflex tests below the reference range obtained in our control subjects (mean ± 2 SD). These patients did not show any characteristic pattern of AEDs, type or frequency of seizures, duration of TLE, lateralization of epileptic focus in EEG-registration compared with patients with cardiovascular responses within normal range. Yet, three out of four patients with clinically significant abnormalities in cardiovascular reflexes were men.