Some patients with HCM have no symptoms (asymptomatic), while others may experience life-threatening symptoms. Both obstructive and nonobstructive hypertrophic cardiomyopathies can cause symptoms. The most common symptoms patients experience may include:
- Shortness of breath
- Chest pain (angina)
- Abnormal heart rhythm (arrhythmia)
- Heart palpitations
- Swelling in the ankles, feet, legs, abdomen and neck veins
As HCM worsens, symptoms of heart failure may become evident. HCM in young adults is often more severe than HCM in older patients. In affected persons, collapse and sudden death may be the first symptom. This can be caused by dangerous arrhythmia or by a blockage of blood outflow to the rest of the body.
Causes and Risk Factors
HCM is generally caused by an inherited genetic mutation (abnormality). Patients with HCM also have a related condition known as myofiber disarray, an abnormal arrangement of the heart muscle cells that is one possible cause for the development of arrhythmia. There are also forms of HCM that are not inherited but are caused by abnormal depositions in the heart muscle or from intense physical training, high blood pressure or heart valve disease.
Patients of any age, gender or ethnicity can develop HCM. Young adults are generally at higher risk for sudden death.