Hypertrophic Cardiomyopathy is the most common cardiomyopathy
- Hypertrophic Cardiomyopathy (HCM) is one of the four primary cardiomyopathies and is an autosomal dominant (or genetic) heart muscle disease.
- HCM often goes undiagnosed but is estimated to affect 1 in 500 adults worldwide.
- Research suggests that hypertrophic cardiomyopathy is more common than reported.
Hypertrophic Cardiomyopathy Overview
Hypertrophic Cardiomyopathy (HCM) is one of the four primary cardiomyopathies and is an autosomal dominant (or genetic) heart muscle disease. HCM is a progressive disease that is caused by a genetic mutation that results in abnormal heart muscle thickening, with scaring often developing between the cells. The part of the heart that thickens is the left and right ventricles and the septum (the wall that separates these two ventricles).The abnormal thickening of the ventricle walls and septum makes it harder for the heart to pump blood, and for a small percentage of people, this can result in life-threatening arrhythmias (abnormal heart rhythms) or even sudden death from heart-related complications.
Read MoreHow Common is Hypertrophic Cardiomyopathy?
Hypertrophic cardiomyopathy is the most common primary cardiomyopathy and is estimated to be the most commonly inherited (genetic) heart disease. HCM affects an estimated 600,00 to 1.5 million, or 1 in 500 people in the United States. This genetic heart muscle disease can occur in people of all ages, genders, and ethnic backgrounds. HCM in children (pediatric cases) is very rare, with an estimated 1 in 20,000 children being affected by hypertrophic cardiomyopathy. Many adults that have HCM are not diagnosed as they experience no symptoms, while many children with HCM are not diagnosed until adulthood or severe symptoms present.As most people with HCM do not have symptoms, most data for the last 20 years has supported the prevalence (how common it is) of HCM at roughly 1 in 500 people. New perspectives, making use of recent and relevant advances in population genetic studies, cardiovascular medicine, diagnostic imaging, fee-for-service testing, etc., has resulted in researchers revising the prevalence of HCM in the worldwide population.
Research suggests that hypertrophic cardiomyopathy is a lot more common, and the current data may be potentially outdated.
Causes
The most common cause of HCM is a genetic mutation that is inherited. There are also other causes of HCM, although further studies are needed to establish why certain factors cause or increase a person’s chances of getting hypertrophic cardiomyopathy.
Genetic mutations can occur in one of several genes that encode the cardiac sarcomere protein and are responsible for causing HCM. The most commonly involved genes are MYH7, TNNI3, MYBPC3, and TNNT2. You can inherit HCM from your parents and may pass it on to your children. Depending on the gene defect (mutation), the type of HCM can vary within a family or between family members. Some people that have the gene for HCM may never develop symptoms.
Other factors that may cause HCM to include high blood pressure, and aging, and in some HCM cases, the cause is still unknown.
Signs and symptoms
Many people that have HCM do not experience any symptoms and can lead a normal life, while other people with HCM may only experience symptoms when the disease progresses to an advanced stage. For a very small percentage of people, their first symptom may be sudden cardiac death.
Signs and symptoms of HCM that may present:
- Shortness of breath, especially during exercise (jogging, running, or climbing stairs)
- Light-headedness
- Fainting or dizziness when standing up quickly
- Passing out
- Chest pain
- Arrhythmias (abnormal heartbeats)
- Tiredness of fatigue
- Palpitations ( feeling of the heart beating too fast)
- Lack of energy
- Syncope (fainting)
While the symptoms associated with HCM are very similar to other conditions, it is essential to contact your health care provider if you have a history of HCM as it is genetic and if you experience any of the symptoms listed below, especially when partaking in any physical activities.
Getting a Diagnosis
When diagnosing HCM, your doctor will take your medical history and complete a physical exam, making notes if there are any heart murmurs. There are also several tests that can be conducted or help to confirm HCM. The most common diagnostic test used is an echocardiogram (ECHO), as it checks the blood flow through the heart and the thickness of the heart muscle. Other diagnostic tests that are used in HCM include:
- Transesophageal echo (TEE)
- Genetic testing
- Stress tests (stress echocardiogram)
- Electrocardiogram (ECG)
- Holter and event monitors are used to detect if there are any abnormal heart rhythms (arrhythmias).
- Cardiac magnetic resonance imaging (MRI)
- Cardiac catheterization
It is essential to seek medical advice if you experience any symptoms, or have a family history as “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 of course, prevent sudden death.”
Treatment and Management options
Once an HCM diagnosis has been established, your healthcare provider will draw up appropriate treatment and management options based on your individual needs and risk identification. Some people may find that lifestyle modifications may be sufficient to control and manage their symptoms. Other people with HCM may need medication, a surgical approach, or a combination of methods to control symptoms and prolong their life.
There are several treatment options and strategies that can be used to control and manage HCM; these include:
- Medications: Medications are not always administered to those with HCM, but they can be helpful in the management and treatment of HCM for some.
- Blood thinners (anti-coagulants)
- Calcium channel blockers
- Anti-arrhythmic medication
- Beta-blockers
- Diuretics
- Devices: If medications cannot effectively manage and treat HCM, then an implanted device may be used to reverse arrhythmias. Devices available for HCM include:
- Implantable cardioverter-defibrillator
- Pacemaker
- Septal reduction or a myectomy surgery.
- Alcohol septal ablation.
- Activity restriction
Long-term Outlook
Most patients with HCM experience no symptoms and have a near-normal life expectancy with good outcomes (no significant complications or limitations). In a few cases, sudden cardiac arrest or death is often the first symptom of HCM that patients may experience. Patients that present with symptoms of HCM at a younger age tend to have higher mortality rates.
As HCM is a chronic and progressive disease, it is crucial to go to follow-up appointments and consult with your doctor if you start experiencing any symptoms. HCM worsens over time if not diagnosed, treated, or managed appropriately. A small number of people with HCM are at high risk for heart complications; they can also vary amongst families and family members. Thus, healthcare professionals must identify HCM patients at high risk so the appropriate treatment and preventative measures can be taken.
Some complications that may be experienced include:
- Sudden cardiac death
- Atrial fibrillation
- Syncope (fainting)
- Heart failure
- Blocked blood flow
- Dilated cardiomyopathy
- Mitral valve disease
- Endocarditis (infection of the heart valves)
- Increased complications during pregnancy
- Stroke
Questions to Ask your Doctor
- If my mother has the gene for HCM but no symptoms, will I have HCM symptoms?
- How common is it for females to have HCM?
- Can children have HCM?
- Do I need to get a genetic test if a family member has HCM?
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