Seizure-related cardiovascular symptoms: Comorbidities or SUDEP risk factors?

Sudden unexpected death in epilepsy (SUDEP) is one of the leading drivers of premature mortality in people with epilepsy (PWE), especially in those with difficult-to-treat epilepsy and frequent tonic-clonic seizures (TCS). Cardiovascular symptoms commonly occur in association with seizures, prompting the hypothesis that SUDEP is primarily linked to seizure-related cardiovascular dysfunction. This short narrative review summarizes the spectrum of cardiovascular alterations in the context of seizures and discusses putative links to SUDEP. Focal seizures go frequently along with increased heart rates (HR) that resolve shortly after seizure cessation. HR decrease and ictal asystole (IA) are rarely observed in focal unaware seizures in a small proportion of people with temporal lobe epilepsy. IA is reported to be a self-limiting benign condition without a link to SUDEP. Focal to bilateral or generalized TCS are typically accompanied by excessively released catecholamines, which underlie, in turn, various postictal symptoms. Prominent, sustained sinus tachycardia is a common and benign finding, whereas ventricular fibrillation/tachycardia were only anecdotally reported in a few near-SUDEP or SUDEP patients. Cases of transient, non-fatal atrial fibrillation were also scarcely described in the aftermaths of TCS. Takotsubo cardiomyopathy was rarely reported following TCS, usually with a favorable outcome. In most recorded SUDEP cases, however, a rather stereotypical fatal cascade was consistently documented, characterized by primary central apnea that occurs in the early postictal phase after a TCS, secondarily followed by bradyarrhythmia and terminal asystole. Blood pressure commonly increases in association with focal seizures and TCS, but the pattern may be complex with transient decreases or no significant change during or after seizures. Apart from the immediate effects on cardiovascular function, increasing evidence suggests that recurrent seizures also have a remote impact on cardiac properties, coined by the term `epileptic heart syndrome'. In conclusion, cardiovascular symptoms related to focal seizures are typically transitory and benign. In contrast, TCS can rarely cause postical onset of ventricular tachycardia and acute cardiomyopathy, potentially leading to sudden cardiac death. SUDEP, in turn, was consistently reported to occur in the aftermaths of TCS primarily due to central apnea. To prevent potentially serious cardiovascular complications, full control of TCS whether by antiseizure medication, neuromodulatory devices or epilepsy surgery should be aimed at.