SLEEP increases the risk of sudden death in individuals diagnosed with epilepsy, a new study carried out at the University of Virginia School of Medicine (UVA), Charlottesville, Virginia, USA, suggests. Both sleep and seizures are characterised by changes in heart rate, and both, in some situations, can cause sudden unexpected death in epilepsy, otherwise known as SUDEP.
Understanding the cardiac changes that occur during a seizure attack is key to identifying the risk of SUDEP in patients diagnosed with epilepsy. During the study, the team investigated the heart rates of patients with epilepsy admitted to the hospital. Most of the patients developed tachycardia, a fast heart rate, following a seizure. However, a notable subgroup of patients had a decreased heart rate; this decreased heart rate was more pronounced when the patients were asleep. Within current research the mechanism of SUDEP is not well understood; however, it is known to mainly occur when a patient’s epilepsy is not well controlled and during sleep when the heart rate is lower. The majority of SUDEP cases occur during sleep.
To gain better understanding of SUDEP, the research team at UVA, led by Andrew Schomer and Mark Quigg, Department of Neurology, monitored the brain and heart activity of individuals with epilepsy as they slept. The study was carried out in a UVA epilepsy monitoring unit between February 2018 and August 2019, on participants aged 17 or older. The researchers evaluated 101 sleep seizures in 41 patients, with a median age of 40.5 years. The participants, on average, had been diagnosed with epilepsy more than 20 years previously. The researchers observed how deeply the patients were sleeping when the seizures occurred. It was noted that some seizures caused the heart rate to increase. The scientists found that the greater the depth of sleep prior to a seizure, the slower the patient’s heart rate was likely to become after the seizure.
“People with poorly controlled seizures have the greatest risk of SUDEP, and seizures during sleep may hold the higher risk,” said Quigg. “Our findings can direct further research to determine how the heart’s and lung’s control systems fail during sleep-related seizures in order to help prevent SUDEP.”