Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get StartedCauses
By Mayo Clinic staffHypertrophic cardiomyopathy is usually caused by gene mutations. It's thought these mutations cause the heart muscle to grow abnormally thick. People with hypertrophic cardiomyopathy also have an abnormal arrangement of heart muscle fibers. The heart muscle cells become jumbled, known as myofiber disarray. This disarray can contribute to an irregular heartbeat (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 (the ventricles) becomes enlarged and obstructs blood flow. This is sometimes referred to as hypertrophic cardiomyopathy with obstruction or hypertrophic obstructive cardiomyopathy. About 70 percent of those with hypertrophic cardiomyopathy have some form of obstruction.
Sometimes hypertrophic cardiomyopathy occurs without significant obstruction of blood flow. However, the heart's main pumping chamber (the left ventricle) may become stiff, which reduces how much blood the ventricle can hold and how much blood gets pumped out to the body with each contraction. Doctors sometimes refer to this as hypertrophic cardiomyopathy without obstruction or nonobstructive hypertrophic cardiomyopathy.
- Cardiomyopathy. American Heart Association. http://www.americanheart.org/presenter.jhtml?identifier=4468. Accessed Jan. 20, 2009.
- Maron BJ. Hypertrophic cardiomyopathy. In: Libby P, et al, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/117866989-4/796148825/1549/451.html#4-u1.0-B978-1-4160-4106-1..50068-6_7427. Accessed Jan. 20, 2009.
- Elliot P, et al. Clinical manifestations of hypertrophic cardiomyopathy. http://www.uptodate.com/home/index.html. Accessed Jan. 20, 2009.
- Hypertrophic cardiomyopathy. The Merck Manuals Online Medical Library: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec07/ch084666/ch084666c.html. Accessed Jan. 20, 2009.
- Ferri F. Cardiomyopathy, hypertrophic. In: Ferri FF. Ferri's Clinical Advisor 2009. St. Louis, Mo.: Mosby; 2008:162.
- You JJ, et al. Life expectancy gains and cost-effectiveness of implantable cardioverter/defibrillators for the primary prevention of sudden cardiac death in patients with hypertrophic cardiomyopathy. American Heart Journal. 2007;154:899.
- Pigozzi F, et al. Sudden death in competitive athletes. Clinics in Sports Medicine. 2008;27:153.
- Maron BJ. Hypertrophic dardiomyopathy and other causes of sudden cardiac death in young competitive athletes, with considerations for preparticipation screening and criteria for disqualification. Cardiology Clinics. 2007;25:399.
- Ingles J. Psychosocial impact of specialized cardiac genetic clinics for hypertrophic cardiomyopathy. Genetics in Medicine. 2008;10:117.
- Morgan JF, et al. Psychiatric disorders in hypertrophic cardiomyopathy. General Hospital Psychiatry. 2008;30:49.