Cardiac arrythmias in patients with epilepsy
Sudden unexplained death in epilepsy (SUDEP) may account for 8-17% of deaths in patients with epilepsy. The MORTEMUS study by Ryvlin et al. (Lancet Neurol 2013; 12: 966–77) made us aware that SUDEP is associated with centrally mediated severe alterations of cardiac and respiratory functions in the early postictal phase.
Cardiac arrhythmias during or after epileptic seizures. Marije van der Lende, Rainer Surges, Josemir W Sander, Roland D Thijs. J Neurol Neurosurg Psychiatry, 2016 Jan;87(1):69-74.
Postictal arrhythmias were mostly found following convulsive seizures and were associated with postictal generalized EEG suppression and SUDEP. In a systematic review of 1167 papers Prof. Ley Sander (Department of Clinical & Experimental Epilepsy, Institute of Neurology, Queen Square London) and his team identified seven distinct patterns of (post)ictal cardiac arrhythmias: ictal asystole (103 cases), postictal asystole (13 cases), ictal bradycardia (25 cases), ictal atrioventricular (AV)-conduction block (11 cases), postictal AV-conduction block (2 cases), (post)ictal atrial flutter/atrial fibrillation (14 cases) and postictal ventricular fibrillation (3 cases). The contrasting clinical profiles of ictal and postictal arrhythmias suggested different pathomechanisms. In line with the MORTEMUS study, postictal rather than ictal arrhythmias seemed of greater importance to the pathophysiology of SUDEP.
It is thought that a diminished cardioprotective parasympathetic tone which can be found for instance in patients with intractable seizures increases the vulnerability for cardiac arrhythmias, asystole, and hence, the risk for SUDEP. The risk prediction for cardiac arrhythmia would have practical consequences for the optimization of antiepileptic drug therapy, the withdrawal of negative inotropic or proarrhythmogenic drugs, and even epilepsy surgery.
Whether cardioautonomic functions as a reduced heart rate variability or baroreflex sensitivity will help us to predict the risk for postictal cardiac arrhythmias in epilepsy is still unclear. However, studies are underway which are investigating the relationship of cardioautonomic and respiratory functions with EEG findings and structural changes in regions of central autonomic control.
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