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, or '''HCM''', is a disease of the /
European Society Of Cardiology clinical expert consensus document on hypertrophic cardiomyopathy. ''
J Am Coll Cardiol ''. 2003; '''42''':1687–713
Though perhaps most famous as a leading cause of
Sudden Cardiac Death in young athletes
Maron BJ, Thompson PD, Puffer JC, McGrew CA, Strong WB, Douglas PS, Clark LT, Mitten MJ, Crawford MH, Atkins DL, Driscoll DJ, Epstein AE. Cardiovascular preparticipation screening of competitive athletes. A statement for health professionals from the Sudden Death Committee (clinical cardiology) and Congenital Cardiac Defects Committee (cardiovascular disease in the young), American Heart Association. ''
Circulation ''. 1996 Aug 15; (4):850-6. (
Medline abstract ;
Full text )
HCM's more important significance is as a cause of sudden unexpected cardiac death in any age group and as a cause of disabling cardiac symptoms.
A
Cardiomyopathy is any disease that primarily affects the muscle of the heart. In HCM, the normal alignment of muscle cells is disrupted, a phenomenon known as ''
Myocardial Disarray ''. HCM also causes disruptions of the electrical functions of the heart. HCM is believed to be due to a mutation in one of many
Gene s that results in a mutated myosin heavy chain, one of the components of the
Myocyte (the muscle cell of the heart). Depending on the degree of obstruction of the outflow of
Blood from the
Left Ventricle of the heart, HCM can be defined as obstructive or non-obstructive.
HCM is also known as ('''IHSS''') and '''hypertrophic obstructive cardiomyopathy''' ('''HOCM'''). A non-obstructive variant of HCM is '''apical hypertrophic cardiomyopathy'''
Rivera-Diaz J, Moosvi AR. Apical hypertrophic cardiomyopathy. ''
South Med J ''. 1996 Jul; (7):711-3. (
Medline abstract ;
Full text ),
which is also known as and '''Japanese variant hypertrophic cardiomyopathy''' (since the first cases described were all in individuals of
Japan ese descent).
While most literature so far focuses on European, American, and Japanese populations, HCM appears in all racial groups. The incidence of HCM is about 0.2% to 0.5% of the general population.
Hypertrophic cardiomyopathy is inherited as an
Autosomal Dominant trait and is attributed to mutations in one of a number of genes that encode for one of the
Sarcomere Protein s including beta-cardiac myosin heavy chain (the first gene identified), cardiac actin, cardiac troponin T, alpha-tropomyosin, cardiac troponin I, cardiac myosin-binding protein C, and the myosin light chains. Currently there are more than 400 mutations in these genes. Approximately 45% of these mutations occur in the β
Myosin heavy chain gene on
Chromosome 14 q11.2-3) while approximately 35% involve the cardiac myosin binding protein C gene. The prognosis is variable, based on the gene mutation. In individuals without a family history of HCM, the most common cause of the disease is a
De Novo Mutation of the gene that produces the β-myosin heavy chain.
An insertion/deletion polymorphism in the
Gene encoding for
Angiotensin Converting Enzyme (ACE) alters the clinical
Phenotype of the disease. The D/D (deletion/deletion) genotype of ACE is associated with more marked hypertrophy of the left ventricle and may be associated with higher risk of adverse outcomes
Doolan G, Nguyen L, Chung J, Ingles J, Semsarian C. Progression of left ventricular hypertrophy and the angiotensin-converting enzyme gene polymorphism in hypertrophic cardiomyopathy. ''
Int J Cardiol ''. 2004 Aug; (2):157–63. (
Medline abstract )
Marian AJ, Yu QT, Workman R, Greve G, Roberts R. Angiotensin-converting enzyme polymorphism in hypertrophic cardiomyopathy and sudden cardiac death. ''
Lancet ''. 1993 Oct 30; (8879):1085–6. (
Medline abstract ).
Individuals with HCM have some degree of or
Hypertension . About two-thirds of individuals with HCM have asymmetric septal hypertrophy.
Many individuals with HCM demonstrate an obstruction to the outflow of blood from the left ventricle. This is known as dynamic outflow obstruction, because the degree of obstruction is variable and is dependent on the amount of blood in the ventricle immediately before ventricle
Systole (contraction).
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Hypertrophic Cardiomyopathy - Echocardiogram - Samogg
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Systolic anterior motion of the mitral valve
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Echocardiogram demonstrating systolic anterior motion of the anterior leaflet of the mitral valve
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"margin: inherit auto"
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