HCM / HOCM

Manual Harrison 17th ed., p.686

Hypertrophic cardiomyopathy (HCM) （Hypertrophic obstructive cardiomyopathy ==> HOCM）

Marked LV hypertrophy; often asymmetric, without underlying cause. Systolic fuction is usually normal; increased LV stiffness results in eleated diastolic filling pressures. Typically results from mutations in sarcomeric proteins (autosomal dominant transmission).

S/S:

secondary to elevated diastolic pressure, dynamic LV outflow obstruction (if present), and arrhythmias; dyspnea on exertion, angina, and presyncope; sudden death may occur.

Other references:

Wikipedia: http://en.wikipedia.org/wiki/Hypertrophic_cardiomyopathy

Hypertrophic cardiomyopathy, HCM or HOCM, is a disease of the myocardium (the muscleof the heart) in which a portion of the myocardium is hypertrophied (thickened) without any obvious cause.^{[1][2][3][4][5][6]} It is perhaps most famous as a leading cause of sudden cardiac death in young athletes.^[7] The occurrence of hypertrophic cardiomyopathy is a significant cause of sudden unexpected cardiac death in any age group and as a cause of disabling cardiac symptoms.

A cardiomyopathy is a primary disease that affects the muscle of the heart. With hypertrophic cardiomyopathy (HCM), the sarcomeres (contractile elements) in the heart replicate causing heart muscle cells to increase in size and so the heart muscle to thicken. In addition, 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 most commonly due to a mutation in one of 9 sarcomeric genes that results in a mutated protein in the sarcomere, the primary component of the myocyte (the muscle cell of the heart).

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.

Myosin heavy chain mutations are associated with development of familial hypertrophic cardiomyopathy.