Scientists say a new scan technique could identify people at risk of collapsing and dying suddenly from a hidden heart condition.
Normally, in people with hypertrophic cardiomyopathy, signs of structural changes in the heart can only be picked up after death.
But University of Oxford researchers used microscopic imaging to spot the same patterns in living patients.
The condition is the top cause of sudden cardiac death in young people.
It is a common, inherited condition, affecting one in 500 people in the UK, which can be fatal in small numbers of people.
Yet many of those with hypertrophic cardiomyopathy, or HCM, have few or no warning symptoms – and some are able to lead perfectly normal lives.
The research team focused on detecting those at risk of sudden death, by looking for abnormal fibre patterns in the heart which could lead to potentially deadly heart rhythms.
This is thought to affect around 1% of people with the condition.
Dr Rina Ariga, study author and cardiologist at University of Oxford, said: “We’re hopeful that this new scan will improve the way we identify high-risk patients, so that they can receive an implantable cardioverter defibrillator early to prevent sudden death.”
She added: “We now need to work on making this scan shorter and faster for patients so that we can test its utility in a large multi-centre study.”
Currently, calculating a patient’s risk is based on the thickness of their heart wall, their family history, plus any unexplained collapses and abnormal heart rhythms.
The difference with the Oxford researchers’ approach is that they used MRI scans to look at detailed images of the structure of the heart muscle to check for “muscle fibre disarray”.
This suggests that heartbeats are not allowed to spread evenly across the heart’s muscle fibres.
The technique, called diffusion tensor magnetic resonance imaging, is normally used on the brain – but advances mean it can now be used on the heart.
Dr Steven Cox, chief executive of charity Cardiac Risk in the Young, said: “It is fantastic to think in the future these clinical findings could be identified in patients living with HCM and used to help in their routine diagnostic and treatments pathways.”
Dr Cox said the key to identifying those at risk in the general population was through cardiac screening “using the cost effective and non-invasive ECG [electrocardiogram] test”.
“This work is an excellent example of cutting-edge, research-led technology that could change the way we diagnose and treat heart and circulatory diseases.”