Hypertrophic cardiomyopathy is usually caused by abnormal genes (gene mutations) that cause the heart muscle to grow abnormally thick. People with hypertrophic cardiomyopathy also have an abnormal arrangement of heart muscle cells, a condition known as myofiber disarray. This disarray can contribute to arrhythmia in some people.
The severity of hypertrophic cardiomyopathy varies widely. Most people with hypertrophic cardiomyopathy have a form of the disease in which the wall (septum) between the two bottom chambers of the heart (ventricles) becomes enlarged and obstructs blood flow. This condition is sometimes called hypertrophic cardiomyopathy with obstruction or hypertrophic obstructive cardiomyopathy. About 70 percent of people with obstructive HCM experience symptoms.
Sometimes hypertrophic cardiomyopathy occurs without significant obstruction of blood flow. However, the heart's main pumping chamber (left ventricle) may become stiff, reducing the amount of blood the ventricle can hold and the amount pumped out to the body with each heartbeat. This condition is sometimes called hypertrophic cardiomyopathy without obstruction or nonobstructive hypertrophic cardiomyopathy.
Feb. 22, 2014
- Maron MS, et al. Overview of hypertrophic cardiomyopathy management including treatment of special problems http://www.uptodate.com/home. Accessed Sept. 26, 2013.
- AskMayoExpert. What tests are needed to confirm the diagnosis of hypertrophic cardiomyopathy (HCM), and what is the role of genetic testing? Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2013.
- Bonow RO, et al. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Philadelphia, Pa.: Mosby Elsevier; 2012. Accessed Sept. 26, 2013.
- Ferri FF. Ferri's Clinical Advisor 2014: 5 Books in 1. Philadelphia, Pa.: Mosby Elsevier; 2014. https://www.clinicalkey.com. Accessed Sept. 26, 2013.
- Jacoby DL, et al. Hypertrophic cardiomyopathy: Diagnosis, risk stratification and treatment. Canadian Medical Association Journal. 2013;185:127.
- Gersh BJ, et al. 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: Executive summary: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2011;124:2761.
- Hypertrophic cardiomyopathy. American Heart Association. http://www.heart.org/idc/groups/heart-public/@wcm/@hcm/documents/downloadable/ucm_312225.pdf. Accessed Sept. 28, 2013.
- Ommen SR (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 3, 2013.