Heart scars reveal sudden death risk

Scans can help doctors decide which patients should be fitted with an implanted defibrillator.

Scarring of the heart muscle visible on scans is an accurate indicator of risk for sudden cardiac death among patients with a common heart condition, according to a study published today in the Journal of the American Medical Association. The finding, made by scientists at Royal Brompton Hospital and Imperial College London, will help doctors decide which patients should be fitted with an implanted device that can restore the heart’s rhythm when it beats abnormally.

In patients with dilated cardiomyopathy, the heart is enlarged, its walls become thinner and weaker and it fails to pump properly. Affecting more than 35,000 people, it is a leading cause of heart failure in the UK and the most common reason for needing a heart transplant. Some patients can benefit from an implanted cardioverter defibrillator device (ICD) but this is an expensive form of treatment, with unpredictable results.

The researchers, who studied more than 470 patients over eight years, found that scarring, which can be detected through a cardiovascular magnetic resonance (CMR) scan, predicts the risk of sudden death more reliably than ejection fraction –  the volume of blood expelled by the heart at each beat, which is the main measure currently used to assess whether to implant an ICD.

Professor Dudley Pennell, a Royal Brompton cardiologist, Director of the National Institute for Health Research Royal Brompton Cardiovascular Biomedical Research Unit and Professor of Cardiology at Imperial College London, said: “Implantable defibrillators can be an effective treatment to prevent risk of sudden death, but we need much more evidence to know which patients would benefit from treatment. Implantable defibrillators don’t work for all patients, and this can be very stressful for patients.

“Our findings mean we can improve the selection of patients to have a device fitted – saving lives and potentially, 30 per cent in costs to the NHS for these patients.”

The study’s lead author, Dr Sanjay Prasad, a Royal Brompton cardiologist and Senior Lecturer at Imperial, said: “Our findings fill an important and significant gap in clinical knowledge about treating dilated cardiomyopathy.

“In the past, it has been challenging to determine in advance which patients would benefit most from a defibrillator. Now we know that a CMR scan for each patient to look for the presence of fibrosis can provide essential information for determining effective treatment.”

Lord Howe, Health Minister, said: “We want our patients to have access to the most effective treatments possible, especially if that treatment could help to save their lives. Research like this is incredibly important and I’m delighted we could support the work of clinicians at Royal Brompton Hospital through the National Institute for Health Research.

“Their work will ensure that patients get the most appropriate treatment, directly saving and improving lives, and help NHS funds to be used most effectively.”

The study was an international collaboration between teams at Royal Brompton Hospital, the National Heart and Lung Institute (NHLI) at Imperial College London, University of Edinburgh Centre for Cardiovascular Science and the Singapore National Heart Centre. It has been funded and supported by the National Institute for Health Research Royal Brompton Cardiovascular Biomedical Research Unit, Imperial College London, the British Heart Foundation, CORDA and Rosetrees Trust.

Based on a news release from Royal Brompton & Harefield NHS Foundation Trust.

Reference

A Gulati et al. 'Association of Fibrosis With Mortality and Sudden Cardiac Death in Patients With Nonischemic Dilated Cardiomyopathy' JAMA. 2013;309(9):896-908. doi:10.1001/jama.2013.1363.