hypertrophic cardiomyopathy (HCM)

its also called Asymmetric Septal Hypertrophy and also some books called it Idiopathic Hypertrophic Subaortic stenosis.

so from the name its characterized by hypertrophy specially if the left ventricle, the ventricle wall becomes thick, stiff, and thick, stiff and solid, and for this reason there will be forceful contraction that rapidly expel or push the blood, but there will be problems in diastole, there will be abnormal diastolic filling, there is no relaxation in the ventricle , the blood in the ventricle is greatly reduced, the so the ejection or expelling from the ventricle is ineffective (amount expelled is low), is in general what we see is decrease in cardiac output.

Pathogenesis: 

 studies said that 50% of HCM cases is inherited autosomal dominant trait and usually occurred by either:

• mutation in gene that synthesize the proteins such as beta-myosin heavy chain which occurs in about 30% of cases. \
• troponin I and T, alpha-tropomyosin and myosin ligh chains. 
• allelic heterogeneity which mean that genotype is caused by different mechanism.

pathology: 
 because of the hypertrophy, the heart become big and will wiegh more than 800gm. we see hypertrophy in the left ventricle and inter-ventricular spetum without dilation, the dilation may occur in the left atrium.

thickening in the walls of the ventricle will not be the same, for that reason it will be called Asymmetric septal hypertrophy.

Metabolism of cardiac muscle

now if we look at the cardiac muscle what is the big difference between the cardiac muscle and skeletal muscle???
 there are many difference, but basically the same metabolism takes place in the skeletal muscle and cardiac muscle except for few points.

functionally cardiac muscle is always working but skeletal muscle work and rest, so the cardiac muscle has a continuous job which requires continuous supply of energy for the contractivity. this is one of the major difference between skeletal muscle and cardiac muscle.

how muscle gets energy???
by the metabolism pathway:

1) glycolysis:
            the major substance here is glucose, glucose is the major fule that require for energy production. (note that glycolysis can be aerobic and anerobic)

so glucose molecule should be delivered in the cell which require insulin.

2) beta-oxidation of fatty acids:
 
3) glycolysis produce lactic acid (lactate)
lactate is utilized through conversion to glucose, its produced by anaerobic glycolysis and kori cycle.
 kori cycle is the conversion of glucose to pyrovate by lacated dehydrogenase enzyem then pyrovate is broken into Acytel CO which could be utalised in the TCA cycle for energy production.

now we compare the heart muscle to skeletal muscle they are the same except for few difference

the heart muscle is always pumping blood, as we say, the skeletal muscle is rapid or sustained movement, during movement it require energy, major pathway naturally aerobic pathway beta-oxidation and TCA cycle.

Beta-oxidation and TCA cycle require presence of oxygen so there are aeirobic pathway.

the aerobic pathway the same in the skeletal muscle as in cardiac muscle.

the main substrates is:
1) free fatty acids.
2) lactate
3) ketone bodies
4) VLDL
5)chylomicron