Status epilepticus produces chronic alterations in cardiac sympathovagal balance.

Abstract

PURPOSE: Status epilepticus (SE) activates the autonomic nervous system, increasing sympathetic nervous system control of cardiac function during seizure activity. However, lasting effects of SE on autonomic regulation of the heart, which may contribute to mortality following seizure activity, are unknown. Therefore, autonomic control of cardiac function was assessed following SE. METHODS: Using Sprague-Dawley rats after 1-2 weeks of recovery from lithium-pilocarpine-induced SE or control procedures, we tested overall sympathovagal control of the heart, the individual contributions of the sympathetic and parasympathetic components of the autonomic nervous system, and baroreflex sensitivity. RESULTS: SE induced a chronic shift in sympathovagal balance toward sympathetic dominance resulting from decreased parasympathetic activity. Baroreflex sensitivity to increased blood pressure was also decreased, likely resulting from diminished vagal activation. DISCUSSION: Chronic alterations in autonomic regulation of cardiac function, characterized by increased sympathetic dominance, occur following SE and likely contribute to subsequent increased cardiac risk and mortality.