Cardiac arrhythmias in sudden unexpected death in epilepsy: A systematic review

Sudden unexpected death in epilepsy (SUDEP) is a devastating event, where the role of cardiac arrhythmias is poorly understood. We systematically evaluated the types and timing of cardiac arrhythmias in SUDEP/near-SUDEP patients from published literature.

A systematic search was performed on PubMed and Embase. Case reports/series were included if cardiac monitoring was documented during SUDEP/near-SUDEP events. Data collected included baseline demographics, seizure types, baseline and peri-event cardiac rhythms, electroencephalograms and respiratory patterns. Onset post-seizure is reported as mean ± standard deviation.

Twenty-two studies were included with a total of 74 patients (54 SUDEP, 20 near-SUDEP). Epilepsy types were generalized (49 %), focal (42 %), generalized and focal (1 %) and unknown (8 %). 93 % of patients did not have significant cardiac comorbidities. Twenty-three events (31 %) occurred at night. Normal sinus rhythm was the most common baseline rhythm (89 %); abnormal baseline rhythms included first-degree atrioventricular (AV) block (n = 3) and QTc prolongation (n = 1). 116 ECG rhythms were documented for 74 patients during the peri-event period. 21 patients (28 %) had documented asystole, with an onset of 6.8 ± 12.3 min post-seizure. There were eight episodes of ventricular fibrillation, six of ventricular tachycardia, five of atrial fibrillation/atrial flutter, and two of high-degree AV block captured. The onset of apnea post-seizure was 3.8 ± 3.7 min.

Cardiac arrhythmias in SUDEP/near-SUDEP are varied. The most common mechanism involves initial respiratory apnea followed by progressive asystole. Some patients have shockable malignant arrhythmias that may benefit from an implantable cardiac defibrillator. Further research is needed to clarify the mechanism and potential preventive measures in SUDEP.