Study Reveals Outdated Guidelines Hinder Diagnosis of Serious Heart Disease in Women

heart muscle and ventricular stiffness. They can also cause cellular changes and modifications to the mitral valve (which separates the left atrium and ventricle). Over time, the heart no longer pumps enough blood with each beat to meet the body's needs.

This is followed by chest pain, shortness of breath, palpitations and arrhythmias. However, some people with HCM do not experience any symptoms, or only with exercise. Over time, the disease progresses and can lead to serious health problems such as atrial fibrillation, heart failure, stroke or arrhythmias that can cause cardiac arrest. It is one of the main causes of sudden cardiac death, especially in people under 35. Hence the importance of detecting this disease as early as possible.

A diagnostic criterion influenced by several factors

There is no single gold standard test for HCM. The diagnosis is based on medical history, auscultation, as well as a whole series of tests. The most important of these is measuring the thickness of the wall of the left ventricle, the main pumping chamber of the heart. For 50 years, the threshold for diagnosing HCM in this way has been 15 millimeters. If the muscle is thicker than this, it is considered that the patient, whoever it is, probably has this heart disease.

Typically, two-thirds of those currently diagnosed are men. But a team of researchers says women are just as likely to get the condition. Their identification is simply less frequent, due to an inadequate threshold value.

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“ It is clear that this threshold, which is based on the results of studies from the 1970s, must be reconsidered. Having the same threshold for everyone, regardless of age, gender or height, completely ignores the fact that the thickness of the heart wall is strongly influenced by these factors “, explains Dr Hunain Shiwani, from the UCL Institute of Cardiovascular Science, who led the research.

It was therefore essential to update this approach, by developing a more personalized diagnostic method, taking into account physical criteria. To do this, the team analyzed cardiac MRI data from more than 5,000 healthy adults using an artificial intelligence algorithm. The latter measured the thickness of the left ventricle wall of each individual. This made it possible to define the “normal” thickness of the ventricular wall according to age, sex and body surface area. The values ​​oscillated between 10 and 17 mm.

Researchers raised the threshold for older, taller people or men. It was lower for younger, shorter people or women.

Patients wrongly diagnosed or “invisible”

They then validated these new thresholds in a cohort of individuals with HCM, involving more than 2,400 patients. They found that they were particularly beneficial for the female population.

A significant proportion of patients in this cohort were diagnosed with HCM despite ventricular wall thickness below the traditional threshold (15 mm). The disease affected approximately 27% of women and 18% of men. Using thresholds adjusted for demographic criteria reduced these proportions to 7% and 15% respectively. The patients had a slightly smaller maximum ventricular wall thickness (18 mm vs 19 mm), but higher z scores (representing the deviation from the mean) (5.1 vs 4.5), specify the authors of the study.

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The next step was to apply the new diagnostic method on a larger scale. The team therefore considered a cohort of more than 43,000 individuals, from the UK Biobank.

The traditional threshold (15 mm) first made it possible to classify 4.3% of the cohort as suffering from HCM. The male/female distribution was very unequal, with only 11% of women diagnosed. The people identified were much taller, heavier and older than the population average.

With the thresholds adjusted according to demographic criteria, the confirmation rate fell to 2.2%, thereby reducing the bias linked to sex. This time, women represented 44% of those identified. “ Ce which is much more realistic given that HCM should affect men and women equally », Notes the UCL press release. Similar reductions in bias by height, weight, and age were also observed.

Correctly identify patients to prevent complications

Redefining abnormal ventricular wall thickness ultimately identified more women and smaller individuals who otherwise would have been underdiagnosed.

This research, funded by the British Heart Foundation, shows that this new personalized approach significantly improves the accuracy of HCM diagnosis. Not only does it prevent affected people from falling “through the cracks”, but it reduces the number of people wrongly diagnosed.

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“ Effective treatments for HCM are beginning to be used for the first time, making it more important than ever to correctly identify people who need them », underlines Dr Shiwani. Sonya Babu-Narayan, clinical director at the British Heart Foundation and clinical cardiologist, speaks of a “new era” for patients and families affected by this cardiomyopathy.

By incorporating other key factors, such as ethnicity, and ensuring that the new thresholds work with echocardiograms used in the clinic, the team hopes to ensure that personalized guidelines are adopted as soon as possible by doctors.

HCM is a serious and potentially fatal disease. It affects approximately 1 in 500 people in the general population. It is most often diagnosed in adolescents and young adults, but it can appear at any age. To date, there is no curative treatment. However, several medications (beta blockers, antiarrhythmics, etc.) can reduce symptoms and prevent complications. Surgical intervention may be necessary in cases of obstructive HCM.