3. Definition
• more than 35 years, the term cardiomyopathies has been
used to describe disorders of the heart with particular
morphological and physiological characteristics; hypertrophy,
restrictive, etc
• Previously was thought to be of unknown origin
• Now described are genetic metabolic and structural
abnormalities
4. Definition
A myocardial disorder in which the heart muscle
is structurally and functionally abnormal, in the
absence of coronary artery disease,
hypertension, valvular disease and congenital
heart disease sufficient to cause the observed
myocardial abnormality
European cardiac society- european heart journal 2007
5. Subtypes
Cardiomyopathies are grouped into specific
morphological and functional phenotypes; each
phenotype is then sub-classified into familial
and non-familial forms
In this context, familial refers to the occurrence,
in more than one family member, of either the
same disorder or a phenotype that is (or could
be) caused by the same genetic mutation and
not to acquired
6. Types of cardiomyopathies
• Dilated
• Hypertrophic
• Restrictive
• Arrhythmogenic right ventricular
cardiomyopathy
7. DILATED CARDIOMYOPATHY
• Accounts for 90%
• Progressive heart muscle dilatation and
hypertrophy- biventricular
• Leads to congestive heart failure due to
systolic dysfunction
8. Pathogenesis of DCM
• Several aetiopathogenic mechanisms have
been demonstrated
– Alcohol
– Inflammatory (infections, immunologic, etc)
– Pregnancy – develops at peuperium
– Genetic predisposition- up to 35%
• A majority are ideopathic
9. Pathogenesis of DCM
• Infections- entero viruses, Cocksackie B-
myocarditis demonstrated
• Alcoholism- i)metabolites, e.g acetaldehyde,
formaldehyde, etc- cause direct
toxicity
ii) thiamine deficiency leading
to Beriberi
10. DCM pathogenesis
• Drugs i) Cytotoxics-e.g Adriamycin
ii)HAART-
• Pregnancy –postpartum or peuperium-CM
Thought to be due to nutritional def;
volume overload;
hypertension;metabolic
derrangments; immunological
11. DCM-PATHOGENESIS
• Genetic- commonly seen in younger patient ,
below 20years of age; due to
autosomal dorminant ; or X-linked
autosomal recessive patternt
• Mutions are seen in mitochondrial genes affecting oxidative
phosphorylation during glucose metabolism
• X- linked defects are linked to defects in dystrophin- a cell
membrane cytoskeleton important in linking internal
cytoskeleton with external basement membrane ; defect seen
in Duchene
12. Arrythmogenic right ventricular
dysplasia/CM
• Linked to Chr 14 defects
• Mainly right ventricular dilatation with failure;
irregular right ventricular myocytes
• Clinically shows arrhythmias- e.g ventricular
tarchycardia or braddycardia
13. MORPHOLOGY
• Gross-enlarged heart 2-3x the expected weight,
flabby; dilated such that the ventricular thickness
may appear normal; mural thrombi common
• Micro- irregular; hypertrophy; irregular; enlarged
nuclei; boxed nuclei; subendocardial or
perimyocyte fibrosis
• These changes don’t correlate with the degree of
disease
16. HCP PATHOGENESIS
• Defects in in genes that code for proteins that
are part of the sarcomere
• Autosomal dorminant with variable
penetrance
• Beta-myosin heavy chain gene (BMHC);
alphatropomysin etc
• Leads to abnormal, forceful contraction
17. morphology
• Gross-massive heart; left ventricular
thickenning; most marked in the
interventricluar septum ; free wall:ventricle
ratio more that 1:3; mural thrombi
• The ventricle becomes elliptical-ovoid
• Leads to poor diastolic feeling
• Micro- extensive myocyte hypertrophy;
irregularity (>40um cf 15um)
18. CLINICAL PRESENTATION
• Mainly exertional dyspnoe due to pulmonary
pooling and poor diastolic filling; systolic
ejectionb murrmur due to aortic obstruction;
anginal pain due to poor perfusion;
arrhthmias; sudden death
19. Restrictive cardiomyopathy
• Rare
• Endomyocardial fibrosis- disease of African
children; fibrosis with restriction hence poor
diastolic feeling; unknown cause
• Loefflers myocarditis- endomyocardial fibrosis-
eosinophilia; thought to lead to the inflammation
and fibrosis
• Endocardial fibroelastosis-mainly left ventriclular
focal submural elastosis; common in infants.
