2. INTRODUCTION
Cardiomyopathy is disease of the heart muscle.
This term is intended to exclude cardiac dysfunction that results from other
structural heart disease, such as coronary artery disease, primary valve
disease, or severe hypertension.
As of 2006, cardiomyopathies are defined as “a heterogeneous group of
diseases of the myocardium associated with mechanical and/or electrical
dysfunction that usually exhibit inappropriate ventricular hypertrophy or
dilatation and are due to a variety of causes that frequently are genetic”
3. GENERAL PRESENTATION
For all cardiomyopathies, the early symptoms often relate to exertional intolerance with
breathlessness or fatigue, usually from inadequate cardiac reserve during exercise.
Shortness of breath may occur during routine daily activity such as dressing and may
manifest as dyspnea or cough when lying down at night.
Peripheral edema
Particularly in younger patients in whom ascites and abdominal discomfort may dominate.
All three types of cardiomyopathy can be associated with atrioventricular valve
regurgitation, typical and atypical chest pain, atrial and ventricular tachyarrhythmias, and
embolic events.
5. DILATED CARDIOMYOPATHY
About one in three cases of congestive heart failure is due to dilated cardiomyopathy.
An enlarged left ventricle with decreased systolic function as measured by left ventricular
ejection fraction characterizes dilated cardiomyopathy.
The dilated cardiomyopathy phenotype is often viewed as a “final common pathway” of
numerous types of cardiac injuries.
LV and/or RV systolic pump function is impaired, leading to progressive cardiac dilatation
(remodelling).
Symptoms of HF typically appear only after remodelling has been ongoing for some
time (months to years).
6. DILATED CARDIOMYOPATHY
DCM is either familial or the end result of myocardial damage produced by a variety
of known or unknown infectious, metabolic, or toxic agents.
One-fifth to one-third of patients have familial forms of DCM.
A reversible form of DCM may be found with alcohol abuse, pregnancy, thyroid
disease, cocaine use, chemotherapy drugs, nutritional deficiencies and chronic
uncontrolled tachycardia.
Although DCM may occur at any age, it most commonly becomes apparent
clinically in the 3rd or 4th decades.
7. CAUSES
Genetic influences
20-50% are familial
Autosomal dominant –predominant pattern
Mutations in genes encoding dystrophin,δ sarcoglycan,troponin T, β MHC
Myocarditis
Alcohol and other toxins
Childbirth (peripartum cardiomyopathy)
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
Symptoms may be gradual in onset
Acute presentation
Misdiagnosed as viral URI in young adults
Symptoms/Signs of heart failure
Pulmonary congestion (left HF) dyspnea (rest, exertional, nocturnal), orthopnea
Systemic congestion (right HF) edema, nausea, abdominal pain, nocturia
Low cardiac output
Hypotension, tachycardia, tachypnea
Fatigue and weakness
Arrhythmia
Atrial fibrillation, conduction delays, sudden death
11. INVESTIGATIONS
Chest radiogram:
Enlargement of the cardiac silhouette due to LV dilatation, although
generalized cardiomegaly is often seen.
Electrocardiogram:
sinus tachycardia or atrial fibrillation,
ventricular arrhythmias,
left atrial abnormality,
low voltage,
diffuse nonspecific ST-T-wave abnormalities,
intraventricular and/or AV conduction defects.
13. INVESTIGATIONS
Echocardiography, CTI, and CMRI
will show LV dilatation, with normal, minimally thickened, or thinned walls, and
systolic dysfunction.
Circulating levels of brain natriuretic peptide(BNP) are usually elevated.
Cardiac catheterization and coronary angiography are often performed to
exclude ischemic heart disease.
16. MANAGEMENT
Limit activity based on functional
status
Salt restriction of 5g NaCl diet
Fluid restriction for significant low
Na+
Initiate medical therapy
ACE inhibitors, diuretics
digoxin, carvedilol
ß-blocking agents
Anticoagulation for EF <30%, or if
patient has a history of
thromboembolism, presence of mural
thrombi
Intravenous dopamine, dobutamine
and/or phosphodiesterase inhibitors
Cardiac transplantation
18. HYPERTROPHIC CARDIOMYOPATHY
Hypertrophic cardiomyopathy is defined as left ventricular hypertrophy that develops in
the absence of causative hemodynamic factors, such as hypertension, aortic valve disease,
or systemic infiltrative or storage diseases.
It is the leading cause of sudden death in the young and is an important cause of heart
failure.
A sarcomere mutation is present in 60% of patients with hypertrophic cardiomyopathy
and is more common in those with familial disease and characteristic asymmetric septal
hypertrophy.
19. HYPERTROPHIC CARDIOMYOPATHY
Hypertrophic cardiomyopathy is characterized by age-dependent and incomplete
penetrance.
More than nine different sarcomere genes with over 1400 mutations have been implicated,
although 80% of patients have a mutation in either MYH7 or MYBPC3
In MYBPC3 mutation carriers, the average age of disease development is 40 years, while
30% remain free from hypertrophy after 70 years.
LV hypertrophy is asymmetric, often with preferential hypertrophy of the interventricular
septum.
It is found in about 1 in 500 of the general population
20. PATHOGENESIS
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.
Hypertrophy is usually greatest in the septum, associated
with obstruction to the flow of blood into the aorta.
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
21. PATHOGENESIS
Systolic obstruction is initiated by drag forces, which push an anteriorly displaced and
enlarged anterior mitral leaflet into contact with the hypertrophied ventricular septum.
Mitral leaflet coaptation may ensue, leading to posteriorly directed mitral regurgitation.
In order to maintain stroke volume across outflow tract obstruction, the ventricle generates
higher pressures, leading to higher wall stress and myocardial oxygen demand.
Smaller chamber size and increased contractility exacerbate the severity of obstruction.
23. CLINICAL FEATURES
About half of all patients with HCM have a positive family history compatible
with autosomal dominant transmission.
Many patients are asymptomatic - echocardiographic finding
Symptomatic
dyspnea in 90%
angina pectoris in 75%
fatigue, pre-syncope, syncope.
↑ risk of SCD
palpitation, PND, CHF, dizziness less frequent
Atrial fibrillation and thromboembolism
24. PHYSICAL EXAMINATION
Most patients demonstrate a double or triple apical precordial impulse and S4 heart
sound.
A rapidly rising arterial pulse: Those with intraventricular pressure gradients.
Systolic murmur:
The hallmark of obstructive HCM is a systolic murmur, which is typically harsh, diamond-
shaped, and usually begins well after the first heart sound.
The murmur is best heard at the lower left sternal border as well as at the apex, where it is
often more holosystolic and blowing in quality, no doubt due to the mitral regurgitation
that usually accompanies obstructive HCM
26. INVESTIGATIONS
ECG: LV hypertrophy and widespread deep, broad Q waves, T wave inversions.
Chest X-ray: may be normal, although a mild to moderate increase in the cardiac silhouette is
common.
Echocardiogram:
The mainstay of the diagnosis of HCM
LV hypertrophy, often with the septum 1.3 times the thickness of the posterior LV free wall.
SAM of the mitral valve, often accompanied by mitral regurgitation, is found in patients with pressure
gradients.
The LV cavity typically is small in HCM, with vigorous motion of the posterior wall but with reduced septal
excursion.
CMRI: is superior to echocardiography in providing accurate measurements of regional hypertrophy
and in identifying sites of regional fibrosis
29. MANAGEMENT
Since SCD often occurs during or just after physical exertion, competitive
sports and very strenuous activities should be proscribed.
Beta-adrenergic blockers
Calcium antagonist
Disopyramide
Amiodarone, sotalol
Pacemaking
Myotomy-myectomy
30. RESTRICTIVE CARDIOMYOPATHY
The least common of the physiologic triad of cardiomyopathies.
restrictive cardiomyopathy, which is dominated by abnormal diastolic function, often with mildly
decreased contractility and ejection fraction (usually >30-50%).
Both atria are enlarged, sometimes massively.
Modest left ventricu1ar dilation can be present, usually with an end diastolic dimension <6 cm.
End-diastolic pressures are elevated in both ventricles, with preservation of cardiac output until
late in the disease.
Much less common than DCM and HCM
32. CLINICAL MANIFESTATIONS
Symptoms of right and left heart failure.
Exercise intolerance and dyspnea are usually prominent.
Commonly have dependent edema, ascites, and an enlarged, tender, and often pulsatile liver.
Kusmaul’s sign is positive.
Heart sounds may be distant, and third and fourth heart sounds are common.
Unlike constrictive pericarditis the apex impulse is usually easily palpable, and mitral regurgitation
is more common.
Thromboembolic complications are frequent in such patients.
33. AMYLOIDOSIS
Amyloidosis is the major cause of restrictive cardiomyopathy.
Several proteins can self-assemble to form the beta-sheets of amyloid proteins, which deposit with
different consequences depending on the type of protein.
Cardiac amy10id is classically suspected from thickened ventricular walls with an ECG that shows 10w
voltage.
A characteristic refractile brightness in the septum on echocardiography is suggestive of the diagnosis,
but neither sensitive nor specific.
Both atria are dilated, often dramatically, and diastolic dysfunction may be more obvious than in left
ventricular hypertrophy from other causes.
Therapy for all types of amyloid is predominantly for symptoms of fluid retention, which often requires
high doses of loop diuretics.
34. MORPHOLOGY
The heart is firm and rubbery with a
waxy cut surface. The atria are
markedly dilated and the left
endocardium, normally smooth has a
yellow – brown amyloid deposit that
gives texture to the surface.
Echo shows thickened walls of both ventricle
without major chamber dilation. The atria are
markedly dilated consistent with chronically
elevated ventricular pressure.
35. FIBROTIC RCM
Progressive fibrosis can cause restrictive myocardial disease without
ventricular dilation. Thoracic radiation, common for breast and lung cancer
or mediastinal lymphoma, can produce early or late restrictive
cardiomyopathy.
Scleroderma causes small vessel spasm and ischemia that can lead to a
small, stiff heart with reduced ejection fraction without dilation.
The pulmonary hypertension associated with scleroderma may lead to
more clinical right heart failure because of concomitant fibrotic disease of
the right ventricle.
36. INVESTIGATIONS
ECG: low-voltage, nonspecific ST-T-wave abnormalities and various
arrhythmias.
Chest x-ray: Pericardial calcification which occurs in constrictive
pericarditis, is absent.
Echocardiography, CTI, and CMRI typically reveal symmetrically thickened
LV walls and normal or slightly reduced ventricular volumes and systolic
function; the atria are usually dilated.
Doppler echocardiography typically shows diastolic dysfunction
37. MANAGEMENT
No satisfactory medical therapy.
Chronic anticoagulation is often recommended to reduce the risk of embolization
from the heart.
Drug therapy must be used with caution.
Diuretics for extremely high filling pressures.
Vasodilators may decrease filling pressure.
Calcium channel blockers to improve diastolic compliance.
digitalis and other inotropic agents are not indicated.
38. Reference
Harrisons
Maron BJ, Moller JH, Seidman C. et al. Impact of laboratory molecular
diagnosis on contemporary diagnostic criteria for genetically transmitted
cardiovascular disease: hypertrophic cardiomyopathy, long-QT syndrome,
and Marfan Syndrome. Circulation. 1998;98
Elliott P, Andersson B, Arbustini E, Bilinska Z, Cecchi F, Charron P, Dubourg
O, Kühl U, Maisch B, McKenna WJ, et al. Classification of the
cardiomyopathies: a position statement from the European Society Of
Cardiology Working Group on Myocardial and Pericardial Diseases. Eur
Heart J. 2008