Cardiovascular autonomic functions in well-controlled and intractable partial epilepsies

Area of Science:

• Cardiovascular Autonomic Function
• Epilepsy Research
• Neurology

Background:

• Epilepsy is linked to autonomic nervous system imbalance, potentially leading to sudden unexplained death in epilepsy (SUDEP).
• Differences in autonomic profiles between well-controlled epilepsy (WcE) and intractable epilepsy (IE) may explain varying SUDEP risks.

Purpose of the Study:

• To investigate and compare inter-ictal cardiovascular autonomic function between partial WcE and IE subjects.
• To identify potential autonomic markers associated with epilepsy severity and SUDEP risk.

Main Methods:

• Autonomic function tests including deep breathing, Valsalva maneuver, isometric exercise, cold pressor, and tilt-table tests were performed.
• Heart rate variability (HRV) was analyzed to assess autonomic tone.
• Autonomic severity score and anxiety status were evaluated in 30 WcE and 31 IE subjects.

Main Results:

• IE subjects exhibited significantly altered HRV with elevated low frequency and decreased high frequency components.
• IE subjects showed higher diastolic blood pressure and reduced heart rate variability during deep breathing tests.
• Intractable epilepsy was associated with significantly higher levels of dysautonomia compared to well-controlled epilepsy.

Conclusions:

• Intractable epilepsy is characterized by increased sympathetic tone, reduced parasympathetic tone, and diminished parasympathetic reactivity.
• More severe dysautonomia in IE subjects suggests a potential predisposing factor for sudden unexplained death in epilepsy (SUDEP).
• Cardiovascular autonomic regulation is altered in refractory epilepsy, highlighting a critical area for SUDEP risk assessment.