Alteration of Cardiac Function in Patients with Temporal Lobe Epilepsy: Different Roles of EEG‐ECG Monitoring and Spectral Analysis of RR Variability

Abstract

Summary: Purpose: Because several reports have described the relation between epilepsy and cardiac arrhythmias and suggest that changes in autonomic neural control of the heart could be involved in the pathogenesis of sudden unexplained death in patients with epilepsy, the aim of this study was to evaluate cardiac function in patients with temporal lobe epilepsy.Methods: Sixty-five patients with epilepsy were evaluated by simultaneous ambulatory 24-h EEG-ECG monitoring, and in 30 of these, power spectral analysis of relative-risk (RR) variability also was carried out, both in the supine position and in a passive tilt position at 60". The power spectrum of RR variability, the two major spectral components detectable at low frequency (LF) and at high frequency (HF), respectively, and the LF/HF ratio were calculated.Results: By EEG-ECG monitoring, we recorded six partial seizures, and in four cases, discharges were associated with sinus tachycardia. However, interictally the occurrence of ventricular and supraventricular arrhythmias was not different from that in normal subjects. The spectral analysis of RR variability, on the other hand, demonstrated in patients with epilepsy a significant decrease in the total RR variability and in both of its components (LF and HF) in the supine position, and of the LF/HF ratio in orthostatic position.Conclusions: These findings suggest that the spectral analysis of RR variability may detect disorders of autonomic cardiac control in patients with epilepsy, even in the absence of abnormal findings during ECG monitoring. This alteration, which is more severe in cases with right EEG focus, could play a role in the pathogenesis of cardiac arrhythmias. Key Words: Temporal lobe epilepsy-Sudden unexplained death in patients with epilepsy-ECG monitoring-Heart rate variabilityAutonomic disorders.Sudden unexplained death in patients with epilepsy (SUDEP) is a well-recognized phenomenon (l), although its pathogenesis is not yet completely understood. In a recent cohort study (2), the maximal overall incidence of SUDEP observed was 1.35 cases/l,OOO person-years, which was similar to values described in previous studies (3,4). In particular, the incidence of SUDEP is increased in males and is correlated with the number of antiepileptic drugs (AEDs) prescribed and with treatment. with psychotropic drugs. It is also associated with alcohol abuse and slightly with mental retardation.With regard to the pathogenesis of SUDEP, the hypothesis of an acute disturbance of the cardiac rhythm as a possible mechanism is supported by various clinical case reports of patients with temporal lobe epilepsy (5,6) Accepted September 13, 1996. Address correspondence and reprint requests to Dr. L. Mum at Department of Neurosciences, Institute of Neurology, Via Roma, 67, 56126 Pisa, Italy and by the finding that both simple and complex partial seizures (CPSs) are consistently associated with tachycardia (7,s) and rarely with bradycardia (9,lO). On the other hand, certain data obtained interictally provide only par...

Pre-ictal heart rate variability assessment of epileptic seizures by means of linear and non-linear analyses

“…Autonomic dysfunction has also been noted in the interictal period, could be the only sign during this phase of clinical calm, and might play an important role in the cause of Sudden unexpected death in epilepsy (SUDEP) (25,26).…”

“…Changes in HRV vary between seizure types; for example in temporal lobe seizures, increased sympathetic and decreased vagal heart rate modulation often precedes ictal electroencephalographic (EEG) changes (27)(28)(29). Previous studies have reported diminished interictal HRV in temporal lobe epileptic patients using conventional short and long-term electrocardiogram (ECG) recordings, but general study with focused on changes in heart rate during pre-ictal phase failed, and many aspects of it has remained unclear (25,(30)(31)(32)(33).…”

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Bradicardia como manifestação epiléptica em epilepsia temporal: relato de caso

“…A monitorização vídeo-ECG/EEG é o melhor método para a diferenciação entre epilepsia e quadros sincopais 23 . A identificação de crise epiléptica causando arritmia cardíaca é necessária, pois implica em terapêutica específica.…”