ABSTRACT
The exact pathophysiology of sudden unexplained death in epilepsy (SUDEP) remains unknown, but a growing body of evidence points to peri-ictal (occurring concurrently with a seizure) respiratory, cardiac, or autonomic dysfunction. Not every case of SUDEP necessarily has the same cause; these causes are also not mutually exclusive. Proposed causes for SUDEP fall into three primary categories: cardiovascular, including ictal arrhythmias or asystole; neurogenic pulmonary edema; or ictal respiratory suppression (Leung et al. 2006; Sowers et al. 2013; Zhao et al. 2014). A retrospective review of data from multiple epilepsy monitoring units examined patients who died from SUDEP. The data suggest that the patients had postictal centrally mediated cardiorespiratory dysfunction, especially associated with antiepileptic drug (AED) withdrawal (Ryvlin et al. 2013). The “lockstep phenomenon” (LSP), which has been identified in animal models, is one potential mechanism for seizures triggering cardiac arrhythmias to cause SUDEP. In LSP, abnormal cardiac sympathetic neural discharges and cardiac arrhythmias are linked temporally to interictal and ictal epileptic activity (Lathers et al. 1987; Stauffer et al. 1989). The mechanism by which this association occurs has not been fully delineated.
