Abstracts

Rationale:
Decreased interictal autonomic cardiovascular modulation in persons with epilepsy was previously reported and might contribute to sudden unexpected death in epilepsy. We aimed to compare autonomic cardiovascular regulation between patients with focal (FE-patients) and generalized (GE-patients) epilepsies which are two major and most frequent forms of the disease.
Method:
Patients with generalized tonic-clonic or focal to bilateral tonic-clonic seizures who did not have somatic or psychiatric comorbidities participated in the study. In 33 FE-patients (mean age 32.0 ± 8.0 years, 12 males), 15 GE-patients (mean age 29.9 ± 10.2, 4 males) and 30 healthy controls (mean age 30.6 ± 6.5 years, 12 males), we recorded RR-intervals (RRI), beat-to-beat systolic blood pressure (BPsys), and respiratory frequency during 5 minutes at supine rest and upon active standing. We calculated RRI-standard-deviation (RRI-SD), RRI-coefficient-of-variation (RRI-CV), total powers of RRI reflecting total cardiac autonomic modulation, low frequency powers of RRI-modulation (LF-RRI) and of BPsys-modulation (LF-BP) reflecting sympathetic modulation, root-mean-square-of-successive-RRI-differences (RMSSD) and high frequency powers of RRI-modulation (HF-RRI) reflecting parasympathetic modulation, supine and standing baroreflex sensitivity (BRS), and the RRI-30:15-ratio reflecting baroreflex response to active standing. We compared autonomic parameters between FE-patients, GE-patients, and controls (Kruskal-Wallis test and post-hoc Mann-Whitney-U-tests; significance: p < 0.05). Data are presented as median and interquartile ranges.
Results:
Kruskal-Wallis test revealed significant differences in all the above parameters except for supine BRS between the three groups. Compared to controls, all autonomic parameters were reduced in FE-patients, but did not differ from control values in GE-patients. Compared to GE-patients, FE-patients had lower RRI-CV (4.18 [3.34-5.61] vs 5.37 [4.02-7.23]; p = 0.044) and higher respiratory frequency (15.0 [13.0-18.0] vs 11.0 [9.0-15.0]; p = 0.008), the other parameters did not differ significantly between FE-patients and GE-patients.
Conclusion:
FE-patients had an overall decrease in autonomic cardiovascular modulation, while GE-patients did not show autonomic dysfunction. Compromised autonomic modulation is a well-known risk factor associated with increased mortality. Hence, our findings contribute to explaining why mortality rate is higher in persons with focal rather than generalized epilepsy.
Funding:
:None.