Scientists for the first time have taken pictures of bleeding inside the heart after a heart attack.
The research, which shows that the amount of bleeding can indicate how damaged a person's heart is after a heart attack, has been published in the journal Radiology.
The researchers, from the MRC Clinical Sciences Centre at Imperial College London, hope that this kind of imaging will be used alongside other tests to create a fuller picture of a patient's condition and their chances of recovery.
People suffer heart attacks when an artery that feeds blood to the heart becomes blocked, stopping the heart's blood supply and depriving the heart muscle of oxygen.
For the study, researchers captured images of bleeding inside the heart in 15 patients from Imperial College Healthcare NHS Trust who had recently suffered a heart attack, using Magnetic Resonance Imaging (MRI).
Analysis of the MRI scans revealed that the amount of bleeding correlated with how much damage the heart muscle had sustained.
Patients who had suffered a large heart attack, where a lot of the heart muscle was damaged, had a lot of bleeding into the heart muscle compared with those whose heart attack was relatively small.
The researchers were able to detect the area of bleeding because of the magnetic effects of iron, which is present in the blood.
Dr Declan O'Regan, the first and corresponding author of the study from the MRC Clinical Sciences Centre at Imperial College London, said: ''Our study gives us a new insight into the damage that heart attacks can cause.
''Using this new scanning technique shows us that patients who develop bleeding inside their damaged heart muscle have a much poorer chance of recovery. We hope that this will help us to identify which patients are at most risk of complications following their heart attack.''