The damage caused by heart disease may make the organ cope better with the dangers of surgery, say researchers.
Damage may trigger protective chemical changes
Mice with symptoms of heart disease were found to be more resistant to the damage caused by cardiac surgery, which involves stopping the heart itself.
Writing in Critical Care Medicine, the researchers believe by understanding the exact chemical reaction they may be able to replicate this with drugs.
The Bristol University team hope to boost the odds for all heart patients.
Almost 30,000 patients a year undergo coronary artery bypass operations, which help replace sections of artery left dangerously narrowed by heart disease.
The heart is stopped during the operation, and may suffer some damage to its tissue as a result.
The study suggests that the pressure of living with heart disease may actually increase the chances of being able to minimise this damage.
Normal mice cannot develop heart disease in the same way as humans, but the Bristol team used mice which had been genetically modified so they are more prone to get the same fatty build-up in their heart arteries if they eat a poor diet.
Some of the modified mice were fed a high-fat diet, so they developed heart disease, while others had a normal rodent diet.
When mock cardiac surgery was carried out on the "heart disease" mice, their hearts coped better with the stresses of the operation than the normally-fed mice.
Professor Saadeh Suleiman, who led the study, said: "The heart is a very clever organ - we think that it has the ability to change its chemical pathways to respond to the damage caused by heart disease.
"We believe that we could target these pathways to help people who are undergoing heart surgery."
However, Professor Suleiman stressed it was still better to avoid surgery altogether by adopting healthy eating habits.
Professor Jeremy Pearson, from the British Heart Foundation, said: "These findings take an important step towards untangling the heart's complex protective mechanisms, which will help researchers devise treatments to reduce the risks for patients during heart surgery."