Relation between ictal asystole and cardiac sympathetic dysfunction shown by MIBG-SPECT

Area of Science:

• Neurology
• Cardiology
• Nuclear Medicine

Background:

• Tachyarrhythmias are common during epileptic seizures, while bradyarrhythmias and asystoles are less frequent.
• Ictal asystole may be linked to cardiac sympathetic denervation caused by epilepsy.

Purpose of the Study:

• To evaluate cardiac post-ganglionic denervation in epilepsy patients presenting with ictal asystoles.
• To assess the utility of I123-meta-iodobenzylguanidine (MIBG) scintigraphy in identifying cardiac denervation.

Main Methods:

• Utilized I123-meta-iodobenzylguanidine (MIBG) scintigraphy (MIBG-SPECT) to measure post-ganglionic cardiac norepinephrine-uptake.
• Compared MIBG uptake (heart/mediastinum ratios) in five epilepsy patients with ictal asystoles to 18 epilepsy patients without bradyarrhythmias and 14 healthy controls.

Main Results:

• Five out of 844 patients experienced ictal asystoles during seizures.
• Cardiac MIBG uptake, measured by heart/mediastinum ratios, was significantly lower in asystole patients (1.58) compared to non-asystole epilepsy patients (1.81) and controls (1.96).
• Cardiological examinations were unremarkable in all groups, suggesting MIBG-SPECT detects subclinical denervation.

Conclusions:

• A pronounced reduction in cardiac MIBG uptake in asystole patients suggests post-ganglionic cardiac catecholamine disturbance.
• Impaired sympathetic cardiac innervation may limit heart rate modulation, increasing the risk of asystole and sudden unexpected death in epilepsy (SUDEP).