Seizures Can Stop The Heartbeat: Does This Cause SUDEP?
The ability of the brain to affect our heart rate is well known by anyone who has felt her heart race after a surprise or passed out at the sight of blood. The electrical activity in the brain during a seizure can also change our pulse and usually causes an increase in heart rate. However, during some seizures, the heart can slow or even stop temporarily, which is referred to as ictal asystole. One study using implantable recorders to monitor heart rhythms in 19 people with focal epilepsy over 24 months found 21% of these people had their hearts stop during a seizure. However, this only occurred during a small number (2.1%) of the total number of seizures. This was also self-limited with the heart restarting on its own.
A review of patients admitted to the epilepsy monitoring unit at Mayo Clinic found that nearly all of the patients found to have significant slowing of the heart during a seizure also had a history of collapsing and becoming limp following the start of a seizure. Many of these patients were also noted to have brief irregular jerks called myoclonus after collapsing. Certain epilepsy syndromes may also have a greater risk for seizures causing the heart to stop, such as benign occipital epilepsy of childhood and anti-NMDA receptor antibody encephalitis.
Treatment of ictal asystole should focus on control of the seizures, which is also the best strategy for reducing the risk of sudden unexpected death in epilepsy(SUDEP). In patients who have intractable epilepsy , the use of a permanent cardiac pacemaker has been investigated. A study of 7 patients with ictal asystole at Mayo Clinic showed a significant reduction of falls after placing a pacemaker. A similar reduction in falls after pacemaker implantation was demonstrated in a study of another 7 ictal asystole patients in Europe. However, a study of 6 patients who underwent pacemaker implantation for ictal asystole at the Cleveland Clinic found that the pacemakers were not being used as the patients were not having further episodes of ictal asystole. It is reasonable to consider pacemaker implantation for individuals with ictal asystole who do not achieve seizure freedom with seizure medications or surgery and who continue to have seizure-related falls.
A direct link has not been proven between ictal asystole and SUDEP, and it is probable that seizure-related respiratory disturbances play a larger role in the pathology of SUDEP. However, the factors causing most cases of SUDEP are unknown, and it is possible that ictal asystole and other abnormal heart rhythms during seizures contribute to the cardiorespiratory instability seen during and following a seizure. When ictal systole is coupled with other autonomic disturbance, it could theoretically increase the risk of a fatal outcome. It is not known whether pacemaker use will reduce the risk of SUDEP in patients with ictal asystole. The recurrence rate of ictal asystole is unknown, and a pacemaker may not impact all of the potential causes of SUDEP. We clearly need more research on cardiac rhythm changes during seizures to understand their impact and to improve the management of this condition.
by Gena Ghearing, M.D.
University of Pittsburgh
Last Reviewed: 1/8/2014