Epilepsy heart find.
Four patients went on to have pacemakers fitted to ensure their hearts kept in step.
Potentially fatal pauses in heart rhythms were detected during seizures in three of these patients.
An epileptic fit occurs when nerve cells in the brain become over-excited. Sometimes this can result in a potentially dangerous irregular heart rhythm.
The implant which identified the irregular heart rhythms was inserted just above the patients' hearts by scientists at University College London.
In the pilot trial, funded by the National Society of Epilepsy, the implant was programmed to record exceptionally low or fast heart rates running at below 40 or above 140 beats per minute.
Heart rhythms were recorded during 377 of a total of 3,377 seizures, the researchers reported in The Lancet medical journal.
The four patients subsequently given pacemakers all experienced periods during which the heart beat ceased temporarily or pulsed very slowly.