Diagnosing Hypertrophic Cardiomyopathy (HCM)
- HCM remains largely underdiagnosed due to many people being asymptomatic or their symptoms being attributed to other cardiovascular conditions.
- Due to the chronic, progressive nature of HCM, early diagnosis greatly improves outcomes and is beneficial when determining available treatment options.
- A complete physical exam and medical history will be part of the initial evaluation for HCM. A family history of HCM would be an indicator that a patient is at risk for this genetic heart condition. It is typically inherited from a family member, though some people with HCM do not have a family history.
- Your cardiologist may use several tests like genetic tests, echocardiogram, electrocardiogram, stress and heart monitors, and cardiac MRI among others to provide a full understanding of the extent of damage to the heart and how it affects the heart's functionality.
What is Hypertrophic Cardiomyopathy?
Hypertrophic cardiomyopathy (HCM) is a chronic and progressive disease state that typically arises from gene mutation(s) in the muscle of the heart. These mutations allow the muscle to become abnormally enlarged. This generally occurs in the walls of the heart's left ventricle."With each beat, your heart pumps out blood, but in order to do that, it also has to receive the blood," Dr. Aeshita Dwivedi, a cardiologist at Lenox Hill Hospital told SurvivorNet. "When the walls of the heart get very thick and abnormal, your heart becomes stiff and becomes less compliant and is not able to accept the blood as it should."
Read MoreWho is at Risk?
A family history of HCM would be an indicator that a patient is at risk for this genetic heart condition. It is typically inherited from a family member, though some people with HCM do not have a family history.The condition usually begins to develop in adolescence and early adulthood, but the average age at first diagnosis is approximately 39 years old. This may be because it takes considerable time for the condition to progress enough that people become symptomatic.
HCM does not have significantly different affected rates between ethnic groups. Although the condition is seen in both males and females, some studies suggest that it is detected earlier in males. Despite it being a common type of genetic heart disease, estimated to affect 1 in 500 people, HCM remains largely underdiagnosed due to many people being asymptomatic or their symptoms being attributed to other cardiovascular conditions.
What Symptoms May Indicate a Need for Testing?
Many people with HCM either do not experience symptoms, or the symptoms are so minor and nonspecific that they do not cause the patient to seek evaluation until the condition has progressed. Oftentimes, symptoms are most pronounced when the person is exercising or upon exertion. In the younger generation, it is more commonly seen in athletes.
Some symptoms that may indicate a need for further evaluation and support a diagnosis include, but are not limited to, the following:
- Chest pain or difficulty breathing, typically upon exertion
- Fainting, usually related to exertion
- Heart murmur or pounding heartbeats
- General tiredness, fatigue, or lightheadedness
How is Hypertrophic Cardiomyopathy Diagnosed?
To make a firm and conclusive diagnosis, cardiologists will evaluate patients with:
- A physical exam
- Thorough medical and family history
- Diagnostic testing/procedures
The primary hypertrophic cardiomyopathy diagnostic criteria include the thickness of the walls of the heart and how the heart functions. Generally, most cardiologists would consider an HCM diagnosis if the left ventricle wall thickness is ≥ 15 mm at any point with no other explanation for the enlargement, or ≥ 13 mm with a family history of HCM or genetic markers of the disease present.
If the patient is a child, relative body surface area calculations are used to determine if the thickness of the heart is abnormal. The thickness can be variable in different parts of the ventricle wall.
However, there is not a specific thickness that provides a conclusive diagnosis alone, as other heart conditions can also cause hypertrophy. Hypertension and aortic stenosis are two conditions that commonly lead to an increase in the thickness of the left ventricle as well. These conditions, amongst others, must be ruled out.
It is also possible for people to have HCM that has not yet progressed to the point where the wall thickness is ≥ 15 mm.
There are clinical guidelines developed by the American Heart Association (AHA) and the American College of Cardiology (ACC) that help guide the diagnosis and treatment of this genetic heart condition.
Physical Exam and History
A complete physical exam and medical history will be part of the initial evaluation for HCM. Family history is also an important aspect of diagnosis since most people with the condition have inherited it from their family tree. Guidelines recommend assessing three generations for a complete family history.
Other cardiovascular events or conditions, such as heart attack or heart failure, may also be related to the disease. However, in some cases, patients do not have a family history at all. Physical exams would include a review of symptoms, including what triggers worsening symptoms, and listening to heart sounds and rhythms.
HCM Diagnostic Tests and Procedures
Hypertrophic cardiomyopathy diagnostic criteria are also evaluated using a series of tests. Your cardiologist may use several of the following procedures to provide a full understanding of the extent of damage to the heart and how it affects the heart's functionality.
- Echocardiograms (or echo) are the most common diagnostic procedure. It allows your healthcare team to evaluate the thickness of the left ventricle and assess how the blood moves throughout the heart. A transesophageal echocardiogram gives the same information as a traditional echocardiogram, but is performed with a probe inserted into the esophagus.
- Electrocardiograms (ECG) are used for many different cardiovascular events. This test provides information on the electrical signals through the heart and can detect arrhythmias or problems with blood flow.
- Cardiac magnetic resonance imaging (MRI) scans provide an image of the heart's structure and information on how it is functioning. This type of scan can also describe the thickness of the walls of the heart and how it is beating.
- Stress tests and heart monitors may also be utilized. Stress tests are particularly helpful because they assess how the heart performs during physical exertion. Many patients only experience symptoms of HCM while exercising. A Holter monitor is similar to a continuous ECG and is worn for just a couple of days. Other heart monitors, like an event monitor, can be worn for longer but only records data when a patient is experiencing symptoms.
- Genetic testing may be performed to help confirm a diagnosis or to determine if other close relatives may be at risk of developing the condition.
- Cardiac catheterization may sometimes be used to give more detailed information regarding the heart. It involves inserting a catheter into part of the heart. This procedure can help determine if surgical intervention is needed.
What is Next After an HCM Diagnosis?
HCM remains largely underdiagnosed. Historically, it was considered to be a relatively rare cardiac condition. However, it has been connected with sudden death of young athletes, increasing awareness of the disease as of late. It is now realized that this condition is not so uncommon, and for many patients, it is quite manageable. It is predicted that there may be as many as 750,000 people in the U.S. living with the condition, but only about 100,000 diagnoses.
This shows that there is a need for increased evaluation and screening for this genetic heart condition. "Hypertrophic cardiomyopathy, when not diagnosed and not treated, carries a high incidence of sudden death," Dr. Philip Weintraub, a cardiologist at NYU Langone Health explained. "So, therefore, one likes to make the diagnosis of a cardiomyopathy secondary to hypertrophic factors because there are things that could be done to prevent its progression and to of course, prevent sudden death."
Due to the chronic, progressive nature of the disease, early diagnosis greatly improves outcomes and is beneficial when determining available treatment options. For some patients, heart-healthy lifestyle changes may be sufficient to manage the disease.
Other people may need to consider medications, including newly FDA-approved Camzyos (mavacamten). In some cases, pacemakers or surgical interventions may be necessary for more advanced diseases.
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