2. CARDIOMYOPATHY
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Group of myocardial diseases that result in cardiac
dysfunction.
Can be primary → mainly confined to the myocardium
or secondary → presenting as the cardiac manifestation of
a systemic disorder.
Based on clinical, functional, and pathologic patterns
classified into three.
3. 1. Dilated Cardiomyopathy
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Most common form of cardiomyopathy.
Dilation of all four chambers of the heart, caused
by a dysfunction in the heart muscle's ability to
contract.
Results in systolic dysfunction (ventricles cannot
pump), causing more blood to remain in the
ventricle which means less blood has left the
ventricle. So there's a decreased flow to the rest
of the body (decreased ejection fraction).
Leading to biventricular CHF. These signs and
symptoms of heart failure are due to two
processes. They're either due to a decreased
ability to pump the flow forwards, Or due to the
blood backing up behind the heart.
4. 4
Most commonly idiopathic; other causes include:
1. Genetic mutation (usually autosomal dominant) - due to
problems with some of the proteins in the muscle cells that
don't allow them to contract quite as well.
2. Myocarditis (usually due to coxsackie virus A or B) - results
in chest pain, arrhythmia with sudden death, or heart failure.
Dilated cardiomyopathy is a late complication.
3. Alcohol abuse
4. Drugs (e.g., doxorubicin, cocaine)
5. Pregnancy - seen during late pregnancy or soon after
childbirth; results in heart failure.
Treatment is heart transplant.
5. 2. Hypertrophic Cardiomyopathy
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Massive hypertrophy of the left ventricle.
Usually due to genetic mutations of the muscle cell proteins, which
don't allow the muscle to contract properly. It compensates for this
decreased contraction ability by hypertrophying. Most common form is
autosomal dominant.
Clinical features include:
1. Decreased cardiac output - Hypertrophy makes the heart so tight
that ventricle cannot fill.
2. Sudden death due to ventricular arrhythmias; hypertrophic
cardiomyopathy is a common cause of sudden death in young athletes.
3. Syncope with exercise - hypertrophy of the ventricular septum
results in functional aortic stenosis.
7. 3. Restrictive Cardiomyopathy
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Restriction from filling the heart during diastole because of decreased
compliance of the ventricular endomyocardium.
The heart muscle isn't able to relax, so the heart isn't able to fill
properly → results in diastolic heart failure.
Causes include:
1. Amyloidosis - proteins are deposited in the heart muscle.
2. Sarcoidosis - granulomas in the heart muscle.
3. Hemochromatosis - iron is deposited in the muscle fibers.
4. Endocardial fibroelastosis (children) - dense layer of fibrosis
and elastic tissue in the endocardium
5. Loeffler syndrome - an eosinophilic infiltrate with inflammation
and eosinophilia that results in fibrosis of both endocardium and
myocardium.
Presents as congestive heart failure.
