Major study reveals why more men than women are diagnosed with deadly heart disease

A diagnosis that could shape your future might be resting on outdated rules. For decades, the key number used to flag a potentially dangerous heart condition—hypertrophic cardiomyopathy—has been the same for everyone. That number is 15 millimeters.

If the wall of your heart's main pumping chamber measures more than that, a diagnosis may follow. But what if you're smaller? Younger? A woman? Researchers now say this one-size-fits-all method may be leaving people behind—especially women—and mislabeling others.

Hypertrophic cardiomyopathy, or HCM, thickens the heart’s muscular wall, making it harder to pump blood. It can lead to irregular rhythms, cardiac arrest, or sudden death. Often inherited, HCM affects about 1 in 500 people. Diagnosing it early can be life-saving. But the stakes are high on both ends. A false positive could mean being barred from careers, denied insurance, or told to stop exercising. That’s why the accuracy of diagnosis matters.

Until now, the most crucial number in HCM screening has been a muscle thickness of 15 millimeters. This cut-off was based on studies done over 50 years ago using older ultrasound tools. It ignores major factors that shape heart size, like sex, age, and body build. While other cardiac measurements are personalized—especially for children—this one has stubbornly stayed static for adults.

In real-world clinics, HCM seems to affect twice as many men as women. Yet researchers insist the condition doesn’t actually favor one sex. So why the skew? The answer may lie in the outdated thickness rule.

Women often get diagnosed later, when they already show more severe symptoms. These include scarring, atrial dilation, and worse long-term outcomes. It’s not that women are less likely to develop HCM. They’re just less likely to meet the outdated criteria in time.

Lower thresholds have already been tried elsewhere. In Asia, cutoffs are 10 millimeters for women and 12 for men. These numbers better reflect average body sizes. But even these changes don’t go far enough. They still apply a flat standard, rather than adjusting for each person’s build.

Now, a new method led by scientists at University College London may fix this.

Dr. Hunain Shiwani and a team at UCL’s Institute of Cardiovascular Science, along with St Bartholomew’s Hospital, designed a new way to judge heart wall thickness. The tool they created uses artificial intelligence to analyze MRI scans with high speed and accuracy.

By examining 5,000 scans of healthy hearts from the UK Biobank, they figured out what counts as a “normal” heart wall thickness for different people. The AI took into account age, sex, and body surface area—the combination of weight and height—to define the expected range for each group.

Then they tested this new system on 1,600 people already diagnosed with HCM. The results were striking. The personalized method increased diagnosis in women by 20 percentage points. That’s not a small bump—it’s the difference between being seen and being missed.

They didn’t stop there. The team checked their approach against over 43,000 people in the UK Biobank, a major long-term health study. Under the old 15-millimeter rule, only one out of every eight people flagged as possibly having HCM was a woman. The rest were older, taller, and heavier than average.

The personalized model shifted the balance. Fewer people overall were diagnosed, which likely means fewer false positives. But nearly half of those flagged were women—about 44%. That’s a far more realistic split, given that HCM is inherited and should affect men and women equally.

Doctors rarely use just one test to confirm HCM. They consider clinical signs, genetic history, imaging, and more. But the thickness of the left ventricle wall remains the most important factor.

The new approach doesn’t aim to replace those other elements. Instead, it offers a smarter foundation. By adjusting thresholds based on your body, it helps doctors catch true cases and avoid mislabeling healthy people.

Dr. Shiwani sees this as long overdue. “It is clear that this threshold, which is based on the results of studies from the 1970s, needs to be reconsidered,” he said. “Having the same cut off for everyone regardless of age, sex or size completely ignores the fact that heart wall thickness is strongly influenced by these factors.”

With new treatments for HCM now being rolled out, early and accurate diagnosis has never mattered more.

Dr. Sonya Babu-Narayan, a clinical cardiologist and director at the British Heart Foundation, agrees. “A diagnosis is itself a life changing event and we should be making every effort to prevent misdiagnosing people,” she said.

Her foundation helped fund the study, which was published in the Journal of the American College of Cardiology. The research suggests that making room for individual differences will help save lives and reduce harm.

“This more personalized approach to defining abnormal heart muscle thickness heralds a new era for accurate diagnosis,” said Babu-Narayan.

The team hopes to expand their work to include other variables, such as ethnicity. They also want to ensure that this personalized approach works not just with MRI but with echocardiogram scans, which are more common in everyday clinics.

If the method holds up in wider studies, guidelines across Europe and the U.S. may soon change. Instead of a single cutoff for all adults, doctors could use flexible thresholds tailored to each person.

This shift would not just improve care for women. It would help people of all shapes and sizes get better answers—and fairer treatment. For many, that could mean earlier intervention, fewer restrictions, and peace of mind.

A small change in how heart thickness is measured could have a big impact on countless lives.

Note: The article above provided above by The Brighter Side of News.

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