The research is the first to reveal that grief can be lethal for people suffering from heart failure. More than 900,000 people in Britain suffer from heart failure, with 60,000 new patients diagnosed each year.

A study by the Karolinska Institute, in Sweden, looked at 500,000 people with heart failure and followed them up for nearly four years.

In that time, around 11 per cent lost loved ones. The study showed that losing a spouse increased the risk of dying by 20 per cent over the period, but that rose to 113 per cent in the first week of bereavement.

Surprisingly, the effect was far greater when a husband or wife died than after the loss of a child, which raised the overall risk of death by 10 per cent, and 31 per cent in the first week.

Bereavement of any close family member increases risk

Overall, a bereavement of any close family member increased the risk of death from heart failure by 28 per cent over the study period and 78 per cent in the first week.

“The findings of the study may call for increased attention from family members, friends and involved professionals for bereaved heart failure patients, particularly in the period shortly after the loss,” said Krisztina Laszlo, the senior author of the study and an associate professor from the Department of Global Public Health at the Karolinska Institute.

The study authors speculated that systems regulating stress and emotional response may be behind the deaths.

“The association between bereavement and mortality was not only observed in cases of loss due to cardiovascular disease and other natural causes, but also in cases of unnatural deaths,” said Hua Chen, the lead author and a doctoral student at the institute.

“Our finding that bereavement was associated with mortality in heart failure patients contributes to and extends the existing literature regarding role of stress in prognosis of heart failure and is consistent with studies reporting associations between bereavement and increased risk of incident cardiovascular conditions.”

The research was published in the Journal of the American College of Cardiology: Heart Failure.