Why is hypertrophic cardiomyopathy, the most commonly inherited heart disease, often undiagnosed?

Hypertrophic cardiomyopathy (HCM) is an inherited cardiovascular disease. Learn more about HCM, its impacts and its symptoms.

May 01, 2022     

Hypertrophic cardiomyopathy (HCM) is a chronic, inheritable disease where there is excessive thickening of the heart muscle. The most frequent cause of HCM is the presence of mutations in sarcomere protein genes. In its progressive form, HCM can lead to serious complications, including increased risk for atrial fibrillation, stroke, heart failure, and in rare cases, sudden cardiac death.

There are two main subtypes of HCM: obstructive HCM and non-obstructive HCM. Obstructive HCM occurs when the left ventricular outflow tract (LVOT) becomes blocked or has reduced blood flow due to the heart walls becoming thick or stiff. In non-obstructive HCM, the thickened heart muscle does not cause restriction of blood flow. 

Roland Chen, MD, Senior Vice President and Head of Cardiovascular Development, Global Drug Development

Roland Chen, MD, Senior Vice President and Head of Cardiovascular Development, Global Drug Development

“HCM is the most commonly inherited heart disease, impacting an estimated 700,000 adults in the U.S., yet 85% of those adults may remain undiagnosed,” said Roland Chen, MD, senior vice president and head of Cardiovascular Development, Global Drug Development at Bristol Myers Squibb. “BMS is committed to helping patients with HCM and other cardiovascular diseases.”  

Fast facts on HCM

  • HCM affects an estimated 1 in 500 people and possibly as high as 1 in 200.*
  • It has also been estimated that ~700,000 adults in the U.S. have HCM, yet ~85% of those adults may remain undiagnosed.^
  • HCM can be a debilitating and life-changing disease that can reduce physical functioning and overall well-being.
  • HCM is the most common inherited heart disease and can run in families. Rates are similar across ethnic groups, although prevalence increases with age and patients are typically diagnosed in midlife.

Why are so many patients undiagnosed?

For many patients, the path to an HCM diagnosis can be long and often confusing. HCM is a diverse disease and can be a diagnostic challenge for doctors because the disease presentation varies across patients, and the symptoms are sometimes nonspecific, with gradual onset. 

Generally, common symptoms may include shortness of breath, tiredness, chest pain, rapid heartbeat and dizziness. Patients may also be asymptomatic or may have mild symptoms that are identified unintentionally.

“HCM is a progressive heart disease,” said Dr. Chen. “In some cases, when HCM symptoms do appear, they may be difficult for doctors to recognize because they can be similar to other health conditions such as exercise-induced asthma, hypertensive heart disease, anxiety, or other cardiac-related conditions, which makes education and awareness even more important.”

Dr. Chen added, “For more than 60 years, Bristol Myers Squibb has been a trailblazer in cardiovascular disease, bringing new and transformative therapies forward for patients. We’re committed to increasing awareness of HCM and providing support, education, and resources for patients and families.” 

* CARDIA study (published in 1995) is a multicenter, U.S.-population-based echocardiography study of 4,111 subjects (aged 23-35), identified the prevalence of HCM as 1:500 people in the general population. The 2015 Semsarian publication identified that the prevalence of HCM-gene carriers could be as high as 1:200.

^ Based on a 2013 ICD-9 claims database analysis (N = 169,089,614) that estimated/concluded: 1. ~ 600,000 patients with undiagnosed HCM (based on analysis’ assumption that 1 in 500 prevalence represents clinically unrecognized cases), 2. ~100,000 patients with diagnosed HCM (based on 2013 U.S. Census population and the ratio of 59,009 patients with a claim for HCM over the total N, stratified by age/gender), and 3. ~700,000 overall U.S. prevalence of HCM.

Hypertrophic cardiomyopathy fact sheet

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