Dilated cardiomyopathy is the most common type of cardiomyopathy and is characterized by left ventricular dilation and systolic dysfunction. Causes include genetic factors in 20-50% of cases as well as myocarditis, alcohol toxicity, and peripartum cardiomyopathy. Hypertrophic cardiomyopathy is caused by mutations in sarcomeric genes and is characterized by asymmetric hypertrophy of the ventricular septum. Restrictive cardiomyopathy results in stiff ventricles with impaired diastolic filling and is associated with conditions causing fibrosis like radiation, amyloidosis, and sarcoidosis. The main types of cardiomyopathy are dilated, hypertrophic, restrictive, and arrhythmogenic right ventricular cardiomyopathy.
2. Introduction
2006 AHA defined cardiomyopathies as “a heterogeneous group of
diseases of the myocardium associated with mechanical &/or electrical
dysfunction that usually (but not invariably) exhibit inappropriate
ventricular hypertrophy or dilatation and are due to a variety of causes
that frequently are genetic.”
Cardiomyopathies either are confined to the heart or are a part of
generalized systemic disorders
5. Definition
Primary (idiopathic) is a disease of unknown etiology that principally
affects the myocardium leading to LV dilation and systolic dysfunction
Most common of the cardiomyopathies
6. Causes
Genetic influences-
20-50% are familial
Autosomal dominant –predominant pattern
Mutations in genes encoding dystrophin,δ sarcoglycan,troponin T,β
MHC etc
Myocarditis
Alcohol and other toxins
Childbirth (peripartum cardiomyopathy)
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9. Morphology
Heart enlarged,heavy,flabby
Mural thrombi common
Dilatation of all chambers,both ventricular hypertrophy
Microscopically-atrophic and hypertrophic myocardial fibres,cardiac
myocytes show degenerative changes
Interstitial and endocardial fibrosis
10. Clinical features-
Highest incidence in middle age
Symptoms may be gradual in onset
Acute presentation
Misdiagnosed as viral URI in young adults
Symptoms/Signs of heart failure
Pulmonary congestion (left heart failure)
dyspnea (rest, exertional, nocturnal), orthopnea
Systemic congestion (right heart failure)
edema, nausea, abdominal pain, nocturia
Low cardiac output
Hypotension, tachycardia, tachypnea
Fatigue and weakness
Arrhythmia
Atrial fibrillation, conduction delays,,sudden death
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12. DCM - Incidence and Prognosis
Prevalence is 36 per 100,000 population
Third most common cause of heart failure
Most frequent cause of heart transplantation
Complete recovery is rare
50% die within 2yrs and 25% survive longer than 5yrs
14. Hypertrophic cardiomyopathy
Characterised by myocardial hypertrophy,abnormal diastolic
filling,intermittent ventricular outflow obstruction
Related to defects in force generation owing to altered sarcomeric
function
Leading cause of LVH,unexplained by other clinical/pathologic cause
Caused by mutation of genes encoding sarcomeric proteins
15. Pathogenesis
Autosomal dominant with variable penetrance
Remaining are sporadic
Mutations are mostly missense
Mutations causing HCM found in genes encoding β MHC,cardiac
TnT,α tropomyosin,myosin binding protein C
16. The major abnormality of the heart
in HCM -- excessive thickening of
the muscle. Thickening usually
begins during early adolescence and
stops when growth has finished.
uncommon for thickening to
progress after this age
left ventricle almost always affected
Hypertrophy is usually greatest in
the septum, associated with
obstruction to the flow of blood into
the aorta
17. Asymmetric septal
hypertrophy with obstruction
to the outflow of blood from
the heart may occur. The mitral
valve touches the septum,
blocking the outflow tract.
Some blood is leaking back
through the mitral valve
causing mitral regurgitation
22. Restrictive cardiomyopathy
Hallmark: abnormal diastolic function
Rigid ventricular wall with impaired ventricular filling ,contractile
functions are normal
Much less common then DCM or HCM
Characterised by primary disease in ventricular compliance resulting in
impaired ventricular filing during diastole
24. Morphology
Ventricles are of normal size
Cavities are not dilated
Myocardium is firm and non compliant
Biatrial dilatation is common
Patchy/diffuse interstitial fibrosis
25. Clinical manifestations
• Symptoms of right and left heart failure
• Echo-Doppler
– Abnormal mitral inflow pattern
-Prominent E wave (rapid diastolic filling)
Almost invariably progresses to congestive heart failure,10% survive
for 10 yrs
26. Amyloidosis
Cardiac enlargement without
ventricular dilatation
Ventricular walls are thickened
and rubbery
Amyloid deposition is most
prominent in
interstitial,perivascular and
endocardial regions