As many as 1,000 cases of Sudden Unexpected Death in Epilepsy (SUDEP) occur each year in the UK.

Some are thought to be due to spells of irregular heart rate during seizures, which can be missed by routine checks.

An implant can continuously monitor the heart and show which patients need a pacemaker, the University College London team told the Lancet.

Professor John Duncan's team at the Institute of Neurology fitted 20 epilepsy patients with the loop recording device, which monitored heart rhythms for up to 22 months.

Heart rhythms were recorded during 377 of a total of 3,377 seizures reported by the patients.

The implants, inserted just above the heart, picked up eight episodes of serious drops in heart rate during the seizures.

Four patients, who were subsequently given pacemakers, all experienced periods in which the heartbeat ceased temporarily or went very slowly.

Sudden deaths

In three of these instances the heart irregularity would have been fatal had they not been fitted with the pacemaker, the researchers believe.

Professor Duncan said: "Most of the cardiac events detected by the device would not have been picked up during routine ECG monitoring, meaning these loop recorders offer a substantial improvement in spotting potentially fatal heart arrhythmias in these patients.

"This device not only offers them a much longer period of monitoring, but it enables them to continue with their everyday activities rather than spending a week in a hospital."

He and his team plan to study people with different types of epilepsy to further define which groups might benefit from a pacemaker.

"We think it will prevent some but not all SUDEPs.

"It may be that some cases of SUDEP are caused by cessation of breathing being the problem and a heart pacemaker would not prevent that," he said.

Margaret Thomas of the National Society for Epilepsy, which funded the research, said: "This research is an important step in the right direction.

"Ultimately, the goal is to get to the bottom of what is causing these sudden unexpected deaths and stop them from happening.

"If it is that some are caused by some sort of heart function abnormality then whatever we can do to remedy this has to be of benefit."

'Funding vital'

A spokeswoman from Epilepsy Bereaved said: "Two years ago, we found that up to 400 of 1,000 deaths a year were potentially avoidable through access to basic epilepsy services to prevent seizures, and this new research adds further hope that potentially fatal epilepsy seizures are treatable.

"We hope that vital funding is forthcoming to ensure access to any life-saving treatment, whether it is having an annual review to check seizures or having a pacemaker."

Simon Wigglesworth of Epilepsy Action said: "To achieve the better standards for epilepsy care set out in the NICE guidance, immediate inward investment by the government is needed, to increase the number of epilepsy nurses and neurologists in the country."