If you have hypertrophic cardiomyopathy, the muscles in the left side of your heart become abnormally thick which makes both filling and emptying of the heart difficult.
If you have hypertrophic cardiomyopathy, the muscles in the left side of your heart become abnormally thick, which makes both filling and emptying of the heart difficult, increasing the workload of the heart. Hypertrophic cardiomyopathy, also called HCM or hypertrophic obstructive cardiomyopathy, occurs in about one in 500 people in the United States. It is the most common cause of sudden cardiac deaths in young adults (under age 35). But it’s not only a disease of the young. It’s increasingly being diagnosed in older adults. It is more common in men.
Symptoms can range from very mild to very serious, including sudden cardiac death. Some people without symptoms are diagnosed with this condition when a heart imaging study or electrocardiogram (ECG) is done for other reasons. There is no cure for hypertrophic cardiomyopathy, but, with proper treatment most people can live a long and healthy life. Less than one percent of people with hypertrophic cardiomyopathy dies from the disease.
Hypertrophic cardiomyopathy is usually caused by a gene abnormality, called a genetic mutation. The mutation occurs in genes that control proteins in the muscle cells of the heart. In about 60 percent of cases, the genetic mutation is passed down through families, called familial hypertrophic cardiomyopathy. The type of inheritance for this condition is known as autosomal dominant, which means if one parent has the gene mutation, there is a 50 percent chance a child will inherit it, and a 100 percent chance if both parents have the mutation.
In about 40 percent of cases, there is no family history of hypertrophic cardiomyopathy, and no abnormal genes found with genetic blood testing. The cause of the nonfamilial type is unknown.
No matter the cause, there are two types of cardiomyopathies, obstructive and nonobstructive. Hypertrophic obstructive cardiomyopathy is the most common type. In this type, the wall separating the left side of the heart from the right side become thick and stiff. This decreases the amount of blood that can fill the left ventricle, which fills with the blood from the lungs to be pumped out to the body. Thickening of the left ventricle is called left ventricular hypertrophy. In nonobstructive cardiomyopathy, the heart muscle thickens, but not enough to cause left ventricular hypertrophy severe enough to reduce blood flow.
People with nonobstructive hypertrophic cardiomyopathy may have mild symptoms, symptoms that only occur with exercise, or no symptoms at all. However, even people without obstructive cardiomyopathy can develop abnormal heart rhythms, called arrhythmias. If the arrythmia occurs in the ventricle, called ventricular tachycardia, it can cause the heart to suddenly stop beating. This may be the cause of sudden cardiac deaths in young adults, especially athletes who have no symptoms or diagnosis of obstructive cardiomyopathy or left ventricular hypertrophy.
About 50 percent of people with hypertrophic cardiomyopathy have no symptoms or have mild symptoms. When symptoms occur, they may include:
These symptoms may be triggered or worsened by exercise or activities that make the heart work harder.
Although hypertrophic cardiomyopathy can be diagnosed at any age, the average age at the time of diagnosis is age 30. A very important key to diagnosis of hypertrophic cardiomyopathy is having a family history of the disease or a family history of sudden cardiac death at a young age. In fact, about one in four people with the diagnosis will have a family history of the condition in a first-degree relative (parent, child, or sibling). Because cardiac death from hypertrophic cardiomyopathy may occur without any symptoms or very mild symptoms, this type of history may lead to diagnostic testing and a diagnosis.
The other key to diagnosis is a history of hypertrophic cardiomyopathy symptoms. On a physical exam, a healthcare provider may listen to the heart for signs of an arrhythmia or abnormal heart sound called a heart murmur. The most important diagnostic tests are ECG, cardiac imaging (echocardiogram or cardiac MRI), and genetic testing.
Because hypertrophic cardiomyopathy is often a genetic condition, genetic testing is recommended both for diagnosis of the patient and for screening for all first-degree relatives for a possible diagnosis.
Treatment for hypertrophic cardiomyopathy includes medications that slow the heart or prevent it from working too hard. These medications include blood pressure and heart medications like beta blockers and calcium channel blockers. Blood thinners (anticoagulants) may be given to reduce the risk of blood clotting inside the heart, where a clot may move into the brain (stroke), or lungs (pulmonary embolism).
In 2022, the U.S. Food and Drug Administration approved the first medication specifically meant to treat hypertrophic cardiomyopathy, called mavacamten (Camzyos). It has been proven to decrease symptoms and improve outcomes. Most patients with hypertrophic cardiomyopathy can be treated successfully with medications. In patients that continue to have symptoms despite optimal medical therapy, and who have left ventricular hypertrophy, surgical procedures may be used to decrease the thickness of the left ventricular wall of the heart. High risk patients, those that are prone to arrhythmia, may require implantable defibrillators. In very rare cases, as a last resort, a heart transplant may be needed. [1-3]
Although hypertrophic cardiomyopathy can be dangerous for some people, for most, the prognosis is good, and patients can have a good quality of life. Let your doctor know if you have any hypertrophic cardiomyopathy symptoms or an unexplained sudden cardiac death in your family. Get help right away for shortness of breath, rapid irregular heartbeat, exertional dizziness, or chest pain. Hypertrophic cardiomyopathy is a rare but important disease. Early diagnosis and treatment can relieve the symptoms and may prevent sudden cardiac death.
