Health bosses at a hospital trust in Nottingham have apologised after a series of infections involving patients undergoing heart valve operations left three dead and five seriously ill.

Nottingham City Hospital has contacted 94 other patients who have undergone similar operations, as five people continue to battle endocarditis, a rare bacterial infection that affects the heart.

Hospital chiefs insist the site’s theatres are not to blame for the infection, and say a full investigation into the origin of the problem has been launched.

Dr Stephen Fowlie, medical director of Nottingham University Hospitals trust, which runs the hospital, said: “We would like to offer our deepest condolences to the families of those patients who have died and our apologies to the patients of families who have been distressed by these events.

“This tragic infection has affected only those patients who have had heart valve operations and we are investigating all the factors that may be common to those patients.”

Medical experts identified a problem on 13 July after tests on a patient who complained of feeling unwell confirmed the cases were linked to heart valve patients.

The mortality rate for endocarditis is between 30 per cent and 70 per cent, although the five patients who are infected are in a stable condition.