Combining two types of heart scan could help doctors to detect a deadly heart condition before symptoms and signs on conventional tests appear, new research co-led by the University of Leeds shows.
The study shows that hypertrophic cardiomyopathy (HCM), a leading cause of heart failure and sudden cardiac death, can be identified by using the two scanning techniques to look at heart muscle cells in patients with a genetic link to the condition but no overt symptoms.
Affecting around 1 in 500 people in the UK, the inherited condition causes the muscular walls of the heart to become thicker than normal, impacting the heart’s ability to pump blood around the body. It is currently diagnosed after the appearance of symptoms including dizziness, chest pain, shortness of breath and temporary loss of consciousness.
The study, published in the journal Circulation and funded by the British Heart Foundation, was carried out by researchers from Leeds, University College London and Barts Heart Centre. They say it offers an unprecedented opportunity to improve treatment for the condition at the earliest stages.
Being able to detect HCM earlier than ever before will also assist trials investigating gene therapies and drug treatments aimed at stopping the disease developing in those at risk.
Research co-lead Dr Erica Dall’Armellina, Associate Professor in Cardiology in the University of Leeds School of Medicine, said: “If we can diagnose HMC earlier, we can save lives. Our study provides evidence that this potentially life threatening and debilitating condition can indeed be detected before symptoms present themselves. This is good news for patients because a greater understanding of how HCM develops may in future lead to better, earlier treatments.”
Researchers studied the hearts of three groups: healthy people, people who already had HCM, and people with an HCM-causing genetic mutation but no overt signs of disease (no heart muscle thickening).
To do this, they used cardiac MRI perfusion (perfusion CMR), which detects problems with the small blood vessels supplying the heart muscle (microvascular disease) and cardiac diffusion tensor imaging (cDTI), a type of MRI scan that shows how individual heart muscle cells are organised and packed together (the heart’s microstructure).
Combining the results of the scans showed that people with overt signs of HCM have very abnormal organisation of their heart muscle cells, and a high rate and severity of microvascular disease compared to healthy volunteers.
Crucially, the scans were also able to identify abnormal microstructure (muscle cell disorganisation) and microvascular disease in the people who had a problematic gene but no symptoms or muscle thickening. They found that 28 percent had defects in their blood supply, compared to no healthy volunteers. This meant that doctors were able to more accurately spot the early signs of HCM developing in patients’ hearts.
The first drug to slow HCM progression – mavacamten – has recently been approved for use in Europe and will allow doctors to reduce the severity of the disease once symptoms and muscle thickening have appeared. Genetic therapies are also in development, which could prevent symptoms entirely by intercepting HCM development at an early stage.
CMR is already being used in some clinics to help differentiate people with HCM from those with other causes of muscle thickening. However, cDTI Is a recent development and currently avaialble only as part of clinical research.
The researchers think that these scans, combined with the revolutionary new therapies, could in the near future give doctors the best ever chance of treating people at risk of HCM early enough that the condition never develops. This would free many families from the torment of seeing their loved ones lives blighted by these devastating conditions.
Better patient care
Research co-lead Dr George Joy, Clinical Research Fellow at University College London, said: “The ability to detect early signs of HCM could be crucial in trials testing treatments aimed at preventing early disease from progressing or correcting genetic mutations. The scans could also enable treatment to start earlier than we previously thought possible.
“We now want to see if we can use the scans to identify which patients without symptoms or heart muscle thickening are most at risk of developing severe HCM and its life-changing complications. The information provided from scans could therefore help doctors make better decisions on how best to care for each patient."
Professor Sir Nilesh Samani, Medical Director of the British Heart Foundation, said: “Hypertrophic cardiomyopathy is an inherited condition that is dignosed in thousands of people in the UK each year. As it progresses HCM can lead to heart failure and increase risk of sudden cardiac death.
“This research shows that the very early changes in the heart caused by HCM can now be picked up before changes are visible to the naked eye. This is important because in the future, as new treatments become available, this may allow the condition to be treated at a stage before irreversible changes have happened.“
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