Read on to learn more about the symptoms and potential complications of HCM.
The Variable Nature of HCM Symptoms
HCM symptoms vary widely from person to person. HCM is estimated to affect between 1 in 500 people to 1 in 200 people around the world. Many people remain undiagnosed, partly because they have no symptoms at all.
Some people with HCM may never develop symptoms or develop them only later in life, while other people are very symptomatic at a young age. Furthermore, some people only experience symptoms with vigorous exercise and have no problems at rest, whereas more severe cases can cause symptoms even while at rest.
Age of Symptom Onset
The age at which people with HCM may experience symptoms is highly variable. HCM is much less likely to be diagnosed in childhood. This is partly because in HCM, the heart muscle can thicken over time with the condition. Thus, even people who have abnormal HCM genes may not have any identifiable heart muscle changes at a young age. The average age at diagnosis is around 40 to 50 years of age.
Signs and Symptoms From Heart Changes
Signs and symptoms of HCM can be caused by obstruction of blood flow out of the heart. They can also be caused by the arrhythmia or heart failure that can develop due to an abnormal heart muscle. Symptoms that occur because of changes to the heart include the following:
Heart murmurExercise intoleranceLight-headednessFaintingShortness of breathChest painFatiguePalpitations
Exercise May Exacerbate Symptoms
Obstructive HCM symptoms can worsened during exercise due to the obstruction of blood flow out of the heart. During exercise, the body’s need for blood flow and oxygen increases, and the heart muscle contracts more vigorously. In people with HCM, this results in even more obstruction of blood flow.
There are also steps you can take to help lessen symptoms, such as by staying well hydrated and avoiding alcohol, hot tubs, and saunas.
Furthermore, exercise may trigger arrhythmia and sudden cardiac death in people with HCM. Just over one-third of sudden cardiac death cases in competitive athletes are associated with HCM, and most of these deaths occurred during competition or practice.
For this reason, people with HCM should discuss the safety of competitive athletics and strenuous exercise with their cardiologist before engaging in physical activity. Light and moderately intense physical activity is generally considered safe.
Secondary Symptoms
People with HCM may have other symptoms which may be unrelated to exercise. This can include palpitations and heart failure.
The abnormal heart muscle arrangement in HCM makes palpitations from arrhythmias more likely. If you have HCM and experience arrhythmias, let your healthcare provider know so appropriate testing can be done. Arrhythmias can be serious and result in sudden cardiac death.
Heart failure symptoms, like shortness of breath, leg swelling, and fatigue, can occur in addition to exercise intolerance in HCM. Heart failure from HCM often occurs later in the course of the disease, a so-called burned-out stage where over many years, the heart fails to pump blood to supply the body efficiently.
Complications of HCM
Many people never experience problems from HCM, however others can develop severe complications that result in disability or death.
Complications from HCM can include the following:
Arrhythmia Heart failure Sudden cardiac death Blood clots and stroke Heart valve infection
HCM Monitoring
People who have been diagnosed with HCM are followed by a cardiologist, or heart specialist, for periodic monitoring. Even people with no symptoms need to be monitored for the onset of symptoms or complications from HCM.
Monitoring in Asymptomatic Individuals
Monitoring HCM and assessment for risk factors for sudden cardiac death should be performed at diagnosis and every one to two years and includes the following:
Symptom assessment Family medical history (particularly for sudden death, cardiac arrest, and arrhythmias) Physical examination Electrocardiogram Heart imaging (typically done with echocardiogram, though sometimes periodic cardiac magnetic resonance imaging, or MRI, is performed as well) Ambulatory rhythm monitoring (such as with a Holter monitor)
Any new symptoms that develop should be followed by a visit to a cardiologist.
Monitoring in Symptomatic Individuals
People with HCM who have symptoms should be assessed annually. Additionally, stress testing is recommended for people with symptoms who do not have signs of obstruction on a resting echocardiogram.
People with HCM symptoms will need frequent follow-ups with a cardiologist to ensure symptoms are well controlled and to have medications adjusted as needed. If symptoms are affecting daily life despite optimal medical treatment, referral for septal reduction therapy, such as with alcohol septal ablation or septal myectomy surgery may be recommended.
Summary
HCM can cause a range of symptoms or no symptoms at all. People with HCM should be seen by a cardiologist at least annually. A cardiologist can assess patients for their risk of sudden cardiac death and monitor the symptoms, complications, and progression of their disease.
A Word From Verywell
While HCM can be a serious condition that can cause symptoms and potentially life-threatening complications, treatments are available and most people with HCM go on to have an average life expectancy. If you have been diagnosed with HCM, it’s important to see a cardiologist regularly and follow a heart healthy lifestyle.
