Nearly 3.7 million Britons are diabetic.
More than 90 per cent have Type 2 diabetes, which is linked to being overweight and having a sedentary lifestyle.
Without a swift diagnosis and the right care, having diabetes can put them at much higher risk of developing heart disease.
It is estimated that nearly a fifth of people who have a heart attack in the UK also have diabetes.
The research, published in the Journal of the American College of Cardiology, has revealed that, after a heart attack, a protein called HIF acts to help heart cells to survive.
But in people with diabetes, fat accumulates within the heart muscle, preventing HIF from becoming active – making diabetics more likely to have heart failure after a heart attack.
The researchers, funded by the British Heart Foundation and Diabetes UK, treated diabetic rats with a drug which activates the HIF protein and were able to encourage the heart to recover after a heart attack.
Further research is now needed to see whether the process can be replicated in humans.
However, the initial results suggest that several drugs known to activate HIF – and currently undergoing clinical trials to treat people with anaemia – could potentially be given to people with diabetes immediately after a heart attack in the future.
Dr Lisa Heather, who led the research, said: “What we have shown with this research is that the metabolism of people with Type 2 diabetes means they have higher levels of fatty acids in the heart.
“This prevents signals going to the heart-protective protein telling it to ‘kick in’ after a heart attack.
“But what is perhaps most exciting is that existing drugs – currently being trialled for people with blood disorders – can reverse that effect and allow the protein to be activated after a heart attack.
“This opens the possibility that, in the near future, we could also use these drugs to help to treat heart attacks in people with Type 2 diabetes.”