Cardiac arrhythmias during or after epileptic seizures

Abstract

Seizure-related cardiac arrhythmias are frequently reported and have been implicated as potential pathomechanisms of Sudden Unexpected Death in Epilepsy (SUDEP). We attempted to identify clinical profiles associated with various (post)ictal cardiac arrhythmias. We conducted a systematic search from the first date available to July 2013 on the combination of two terms: 'cardiac arrhythmias' and 'epilepsy'. The databases searched were PubMed, Embase (OVID version), Web of Science and COCHRANE Library. We attempted to identify all case reports and case series. We 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). Ictal asystole had a mean prevalence of 0.318% (95% CI 0.316% to 0.320%) in people with refractory epilepsy who underwent video-EEG monitoring. Ictal asystole, bradycardia and AV-conduction block were self-limiting in all but one of the cases and seen during focal dyscognitive seizures. Seizure onset was mostly temporal (91%) without consistent lateralisation. Postictal arrhythmias were mostly found following convulsive seizures and often associated with (near) SUDEP. The contrasting clinical profiles of ictal and postictal arrhythmias suggest different pathomechanisms. Postictal rather than ictal arrhythmias seem of greater importance to the pathophysiology of SUDEP.

Keywords: CARDIOLOGY; EPILEPSY; SUDDEN DEATH.

Figure 1

Schematic overview of the mechanisms for seizure-related asystole. Ictal asystole is strongly associated with temporal lobe seizures. It could be a direct consequence of epileptic activity stimulating the central autonomic network or an indirect effect of the seizure (eg, catecholamine release) evoking a vasovagal reflex. Ictal asystole is self-limiting, as cerebral anoxia caused by the asystole ceases the seizure. In contrast, postictal asystole is associated with convulsive seizures and could be fatal. Postictal apnoea is often preceded by apnoea and/or PGES. Prolonged apnoea eventually causes arousal as well as bradycardia and asystole. Postictal coma may, however, block the arousal effect and thus the resumption of ventilation, explaining why postictal asystole may lead to SUDEP. SUDEP, sudden unexpected death in epilepsy; TLS, temporal lobe seizure, CS, convulsive seizure, CANS, central autonomic nervous system; PGES, postictal generalised EEG suppression.