Heart rate variability (HRV) could help assess risk of sudden unexpected death in epilepsy (SUDEP) in people with epilepsy, according to a new Portuguese study in the journal Epilepsy Research.
Researchers Maria Teresa Faria and colleagues explained that people with epilepsy, especially treatment-resistant epilepsy, have lower HRV. They said this reduced variability is a risk factor for sudden death in other diseases.
The researchers included 23 people, aged between 16 and 55 years, who have generalised tonic-clonic seizures in the research, as these types of seizure are known to be a risk factor for SUDEP. They measured HRV every five minutes, and looked at results during daytime, during night time and before and after a tonic-clonic seizure. The data were compared with values from people without epilepsy.
About a third (30%) had heart disease risk factors, such as smoking and high blood pressure, but none had had heart disease previously.
The team found that HRV was significantly lower in the period after a seizure had occurred. They also found that HRV was generally lower in the people in the study than people without epilepsy.
However, there were no significant differences in HRV between other measured factors, such as between daytime and night time. There was also no significant difference in HRV between seizures starting in the temporal lobe or elsewhere, and whether or not there was a heart-related risk factor or not.
The team concluded that their research confirms a heart-related risk factor in people with treatment-resistant epilepsy, and they said this may play a part in some SUDEP cases. They said that identifying these kinds of heart-related problems can be a marker for a higher risk of SUDEP.
The full study is available online and there is more information about SUDEP on the Epilepsy Action website.