Dynamic alterations in cardiac autonomic regulation during recurrent generalized seizures.

Epileptic seizures are increasingly recognized as systemic events that can disrupt not only brain activity but also peripheral physiological systems, including cardiovascular function. Clinical studies have documented peri-ictal cardiac abnormalities such as bradycardia, asystole, and altered heart rate variability (HRV), especially during generalized tonic-clonic seizures (GTCS). These disturbances are thought to be associated with seizure-related alterations in autonomic regulation, yet the underlying mechanisms and their evolution over time remain incompletely understood. Sudden unexpected death in epilepsy (SUDEP) represents a severe clinical outcome in epilepsy and is frequently associated with generalized convulsive seizures. Postmortem and video-EEG monitoring studies, such as the MORTEMUS study, suggest that fatal events often involve a cascade of cardiorespiratory dysfunction, with respiratory failure typically preceding cardiac arrest. While these observations highlight a link between seizures and autonomic compromise, SUDEP is a multifactorial process, and the specific contribution of altered cardiac autonomic regulation remains difficult to define in clinical settings. Clinical investigations of autonomic function in epilepsy have yielded inconsistent findings. Some studies report reduced HRV, suggesting impaired autonomic regulation, whereas others report differing patterns of autonomic imbalance. These discrepancies may reflect differences in seizure type, disease duration, and experimental conditions, and underscore the need for controlled experimental models to dissect how seizures influence autonomic regulation over time.