Scientists have developed a simple blood test that can predict which heart disease patients face the greatest risk of life-threatening complications.
Here's the cruel paradox of hypertrophic cardiomyopathy (HCM for short, this is a genetic condition where the heart's muscular walls become abnormally thick): Doctors can diagnose it but they can't predict it.
Some patients live perfectly normal lives. Others develop heart failure or die suddenly. Until now, there's been no way to tell how those suffering from this condition will react to it.
That might be about to change. Researchers from the Harvard Medical School and the University of Oxford have been studying a protein that acts like an early warning system for the heart.
And the results suggest a routine blood test could finally answer the question that haunts an estimated one in 500 people living with the condition -- what happens next?
HCM is exactly what it sounds like -- abnormally thick heart muscle, caused by faulty genes passed down through families. The thickened walls become stiff, struggling to relax between beats. Blood flow suffers.
For some, it's a minor inconvenience. For others, it's deadly.
The British Heart Foundation puts it bluntly -- after an HCM diagnosis, patients and their families want to know what the future holds. But, till now, doctors haven't had good answers.
When your heart sends an SOS
Enter a protein named NT-proBNP. Think of it as your heart's distress signal. When the heart muscle is straining -- thickened, scarred, blocked -- it pumps out more of this protein into the bloodstream. Measure the levels and you're essentially eavesdropping on how hard your heart is working.
Scientists have known about NT-proBNP for years. What's new is understanding just how much it can tell us about HCM.
Last year, researchers published results from 282 patients with the obstructive form of the disease (that's where the thickened muscle actually blocks blood flow).
The findings, published in the European Heart Journal, were stark. High NT-proBNP levels correlated with everything you don't want -- reduced blood flow, scarred heart tissue, worse exercise capacity (Coats et al., 2024).
More striking still -- when patients started newer treatments, their NT-proBNP levels plummeted by 79 per cent within two months. Stop the treatment and the levels bounced right back. It's a remarkably precise gauge of what's happening inside the heart.
'This study shows that measuring various proteins circulating in the blood could help predict how the heart is functioning and future risk of complications,' Professor Bryan Williams, chief scientific and medical officer, British Heart Foundation, told The Guardian newspaper.
The personalisation problem
Not everyone with HCM needs aggressive treatment. For some, monitoring is adequate. Others need implantable defibrillators to prevent sudden death or even surgery to carve away excess muscle. The trick is knowing who needs what kind of treatment.
A blood test could split patients into risk groups. High levels? Time for serious intervention. Low levels? Perhaps watchful waiting is enough. This blood test means no more guesswork. No more treating everyone the same and hoping for the best.
According to the American College of Cardiology, NT-proBNP has another advantage -- it's relatively unaffected by age, kidney function or body weight. That makes it more reliable than many other cardiac markers across different populations.
The test itself is just a standard blood draw. Most hospitals already have the equipment to measure it; they don't need new expensive scanners or specialist labs.
Williams sees the potential reaching beyond individual treatment decisions. 'This new method may also provide insights in the evolution of the structure and function of the heart in people with HCM that could point to new ways of treating this condition to reduce future risk,' he said.
Researchers are careful not to oversell -- more studies are needed, thresholds need establishing, treatment protocols need refining. But for millions living with HCM, many of them undiagnosed, a simple blood test could now mark the difference between anxiety and action, between wondering and knowing.
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