Mending Broken Hearts

Probing the heart’s muscle fibres to tackle defects and disease


When 23-year-old footballer, Fabrice Muamba, stepped out onto the pitch back in 2012, no-one expected he would be carried off in an ambulance after a serious cardiac arrest.
Thankfully, doctors managed to save the young man’s life, but Muamba’s near-miss underlines the potentially stark consequences of heart defects, particularly for those with an undiagnosed and possibly life-threatening condition.
Around 9 in every 1,000 babies born in the UK are affected by a particular type of heart defect known as ‘congenital heart disease’. This term incorporates a number of different conditions: some can be mild or manageable with treatment, but others can be life-changing.
There’s no straightforward cure, but we’ve made huge progress in treatment and science is helping us to go even further.
As research and technology advances, we’re learning more about how defects occur. This vital research may help us to improve treatments, but it could also allow us to better diagnose conditions before a baby is even born.
And knowing about a condition then could have major implications: for a small number of conditions it may actually be possible to reverse congenital heart disease at the fetal stage.
The experimental set-up on I13
But to get there requires a lot of research. The heart is a complex organ, and sometimes very significant defects can be traced back to developmental issues on the smallest scale. That’s why Dr Andrew Cook and his group from University College London (UCL) are studying the tiny fibres that make up the heart’s muscular wall.
Known as the myocardium, the heart’s muscles contract and relax to pump blood around the body.
Because they’re so central to the function of the heart, the individual fibres that make up these muscles must be precisely aligned – if they’re not then the heart won’t pump correctly.
This can cause real problems when the body is put under stress – for instance, when running or in surgery – as these muscles might falter and thereby damage the heart.
We still don’t know enough about how the heart’s muscle fibres form, or at what stage in a pregnancy they become misaligned. And so Andrew and his group are using Diamond’s Imaging and Coherence beamline (I13) to study the process.
“Like a grain in wood, these fibres are oriented in a certain direction. We want to study how this alignment is formed and how it might be correlated to congenital heart defects”, Andrew explains.
“We’re seeing hearts with major problems, like artery defects, also showing signs of misalignment in the heart muscle fibres. Why is that? Could there be a link there?
“If we can answer these questions, we can develop new ways of diagnosing, treating and, yes, even correcting congenital heart disease”.

Andrew’s research is helping to unpick some of the uncertainty surrounding congenital heart disease, but the impact of the study goes even further. The UCL group use a technique called X-ray phase contrast imaging for their research.
This relatively non-destructive technique uses light waves to create an intricate picture of matter and its surroundings. At Diamond, the group are pushing the boundaries of what this technique can achieve, opening up new avenues for the study of human hearts.
This is not just exciting for early-stage medical research: it may also have applications in a clinical setting. If it’s further progressed, phase contrast imaging could help develop new ways of performing non-surgical diagnosis of heart defects.
At the moment, these things are impossible to properly see beyond a certain level of detail without surgery. We can detect heart defects using a range of techniques – from MRI scans to blood tests. At the foetal stage, ultrasound is often used to identify potential problems.
But it’s not always easy to scrutinise the exact problem with a patient’s heart without exposure to radiation. Although radionuclide tests do exist, the amount of radiation needs to be very small, meaning that the information clinicians get is not as detailed as it could be.
But phase contrast imaging uses less radiation than this test, and yet is capable of producing more in-depth information than ultrasound, MRI scanning and other techniques.
If we can further develop phase contrast imaging for use on human hearts – as Andrew and his team are currently doing – we may see it become widely used in clinical diagnosis to provide patients, expectant mothers and medical practitioners with more in-depth information on individual heart defects.
In the 1950s, only 2 of every 10 babies born with complex congenital heart defects made it to their first birthday. But thanks to the great work of scientists and charities like the British Heart Foundation, we now have 8 in 10 children with congenital heart disease surviving to adulthood.
With research like Andrew’s, that number will continue to increase, as more lives are saved and more hearts kept beating.

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