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Cardiovascular System
Lecture 3
Cardiomyopathy, Pericardial disease
& Cardiac Tumors
Dr. Samir Al Bashir
Cardiomyopathies
• Cardiomyopathies have been classified into three forms:
– Dilated Cardiomyopathy
– Hypertrophic Cardiomyopathy
– Restrictive Cardiomyopathy
Dilated Cardiomyopathy (DCM)
• DCM is the most common form, accounting for about
90% of cases.
• Characterized by progressive cardiac hypertrophy,
dilation and contractile (systolic) dysfunction
(ineffective contraction, patients may have an ejection
fraction of less than 25%).
• Most common between ages of (20-50 years), men >
women.
Dilated Cardiomyopathy (DCM)
• End stage by time of Dx. & no specific pathologic
features at autopsy in majority of cases.
• Five general pathways:
– Inherited genetic abnormalities (20% to 50% ).
– Viral myocarditis: presence of nucleic acids of
coxsackievirus B and other enteroviruses.
– Toxic chemicals: Alcohol abuse, Cobalt and
Chemotherapeutic agents (Doxorubicin).
– Pregnancy: occurs late in pregnancy or several weeks
post partum (peripartum cardiomyopathy) .
– Iron overload: DCM most common manifestation
DCM: Genetic and familial
conditions
• Mutations in cytoskeletal protein genes such as:
– Dystrophin gene on chromosome X (Becker and
Duchenne muscular dystrophy).
– Genes encoding desmin, merosin, and dystrophinassociated proteins termed sarcoglycans.
• Abnormalities in certain mitochondrial enzymes.
• Mutations in certain sarcomere protein genes (e.g., βmyosin and cardiac troponin T).
DCM: Pathology
• The heart is enlarged and flabby, weighs 900 g (2-3X
normal), there is dilation of all chambers.
• Dilation and poor contractile function cause stasis of
blood → development of fragile mural thrombi and
subsequent emboli.
Microscopic features are non-specific
• Myocyte hypertrophy
• Interstitial fibrosis, wavy fiber change
• Iron accumulation with iron overload
• Scanty mononuclear infiltrate (sometimes)
DCM: Clinical Features
• Most cases arise sporadically (except familial cases).
• Patients develop progressive congestive heart failure.
• Prognosis is very poor (except peripartum DCM):
– 50% die within 2yr, 75% die within 5yr due to (CHF,
embolic complications or ventricular arrhythmias).
• Cardiac transplantation is the only mode of therapy
DCM: Four-chamber dilation and hypertrophy.
DCM: Histology demonstrating variable myocyte
hypertrophy and interstitial fibrosis
Hypertrophic Cardiomyopathy (HCM)
Asymmetric septal hypertrophy or
Idiopathic hypertrophic subaortic stenosis
It is characterized by:
• Myocardial hypertrophy which causes powerful
contractions that rapidly expel blood from the
ventricular cavities.
• Impaired diastolic filling because of the stiff, thick wall
of the ventricle.
• Intermittent ventricular outflow obstruction (in many
cases) .
So the basic problem is an inability to fill a hypertrophic
left ventricle during diastole. Ejection is forceful but
ineffective because the amount of blood in the left
ventricle is greatly reduced.
Hypertrophic Cardiomyopathy (HCM)
Asymmetric septal hypertrophy or
Idiopathic hypertrophic subaortic stenosis
Pathogenesis:
• In 50% of cases, HCM inherited as an autosomal
dominant trait
– Mutations in genes encoding sarcomeric contractile
proteins (70-80%):
• -myosin heavy chain (commonest )
• Troponin T, myosin binding protein C
• Allelic heterogeneity
HCM: Pathology
• Hypertrophy of LV and interventricular septum “IVS”,
without dilation (the left atrium may be dilated). (800
gm+)
• IVS is thicker than the free (lateral) wall of the left
ventricle, and is most evident in subaortic region.
• Asymmetric septal hypertrophy is often associated with
functional ventricular outflow obstruction during
systole (25%) which is caused by abnormal anterior
motion of the mitral valve leaflet during systole.
• This motion lead to recurrent, forceful contact between
the septum and the anterior mitral leaflet causing
thickening of the anterior mitral leaflet and adjacent
septal endocardium.
HCM: Pathology
Microscopically
• Irregular arrangement of hypertrophied abnormally
branching myocytes
• Myocardial fibrosis (late stage)
HCM: Clinical
•
•
•
•
•
•
•
Exertional dyspnea
Harsh systolic ejection murmur
Anginal pain because of myocardial ischemia
Atrial fibrillation with thrombus formation
Ventricular arrhythmias and sudden death
Increased risk of infective endocarditis
Later, progressive myocardial fibrosis may cause
congestive heart failure.
Prognosis: varies with the genetic defect, so molecular
diagnosis is useful
HCM: There is asymmetric hypertrophy of the septal
muscle, and the left atrium is enlarged.
HCM: disarray, extreme hypertrophy, and peculiar
branching of myocytes as well as interstitial fibrosis
Restrictive Cardiomyopathy (RCM)
Characterized by primary decrease in ventricular
compliance, resulting in impaired ventricular filling
during diastole.
• It is the least common type of Cardiomyopathy.
• The problem is a stiff and inelastic ventricle that can be
filled only with great effort.
• Myocardial contractility, although often normal early in
the course of the disease, usually declines, causing
congestive heart failure in later stages.
• Symptoms: fatigue, exertional dyspnea, chest pain, and
arrhythmias
RCM
Causes:
• Endomyocardial fibrosis (the most common cause)
accounts for up to 10% of cases of childhood heart
disease in tropical areas.
• Eosinophilic
endomyocardial
fibrosis
(Löffler
syndrome), is rare.
• Genetic factors are not clearly defined, but may account
for some cases (desmin mutations)
• Additional important causes:
– Amyloidosis–systemic or senile cardiac (transthyretin)
– Sarcoidosis
– Radiation injury to the heart.
– Endocardial fibroelastosis
RCM: Pathology
• Tropical endomyocardial fibrosis and Löffler syndrome:
– The atria are dilated, and the ventricles of normal size
– The endocardium is thick and solid (left ventricle).
– Microscopically: dense fibrosis in endo &
myocardium.
• Eosinophilic endomyocardial fibrosis:
– infiltration by eosinophils (early stages).
• Endocardial fibroelastosis (uncommon):
– Occurs mostly in children < 2 years of age,
– Abundant fibroelastic tissue in the endocardium
revealing porcelain-like appearance).
Pericardial Effusions
Accumulation of fluid in the pericardial space, fluid
nature varies with the cause. Major types and their
causes are:
 Serous: congestive heart failure, hypoalbuminemia
 Serosanguineous: chest trauma, malignancy
 Chylous: mediastinal lymphatic obstruction
 Fibrinous / Serofibrinous: RF, connective tissue
diseases (SLE), MI and post-MI, trauma & uremia
 Blood (Hemopericardium): ruptured aortic aneurysms,
ruptured myocardial infarcts, penetrating traumatic
injury to the heart.
Pericarditis: Pericardial Inflammation


Pericarditis is usually secondary to:
 Myocardial
infarction, cardiac surgery, or
radiation to the mediastinum.
 Associated with systemic disorders, mostly with
uremia
 Rheumatic fever, systemic lupus erythematosus
(SLE), and metastatic malignancies (bloody
effusions).
Primary Pericarditis is uncommon, mostly of viral
origin and sometimes may be caused by other
organisms (pyogenic bacteria, mycobacteria and
fungi).
Pericarditis: Morphology
• In uremia, and acute rheumatic fever: the exudate is
fibrinous and reveals a shaggy irregular pericardial
surface (bread and butter pericarditis).
• Viral pericarditis  fibrinous exudate.
• Acute bacterial pericarditis  fibrinopurulent exudate.
• Tuberculosis caseous materials.
• Pericardial metastases  shaggy fibrinous exudate
and a bloody effusion.
• Chronic Pericarditis: Ranges from slight adhesions to
dense fibrotic scars that encases the heart so it cannot
expand normally during diastole, a condition called
constrictive pericarditis.
Pericarditis: Clinical




Atypical chest pain (worse on reclining), and harsh
friction rub.
Significant exudate  signs and symptoms of cardiac
tamponade (weak distant heart sounds, distended neck
veins, declining cardiac output, and shock).
Chronic constrictive pericarditis  venous distension
and low cardiac output.
Pericarditis may
 Cause immediate hemodynamic complications if a
significant effusion is present
 Resolve without significant sequelae
 Progress to a chronic fibrosing process.
Fibrinous Pericarditis
Hemorrhagic Pericarditis
Cardiac Tumors
• Primary heart tumors are rare.
• Metastatic neoplasms are seen in up to 10% of patients
dying of disseminated cancer, mostly involving
pericardium.
• The most common primary neoplasms that metastasize
to the heart are:
– Carcinomas of the lung and breast,
– Malignant melanomas,
– Lymphomas and leukemias.
Metastases may reach the heart via lymphatic, venous,
or arterial channels.
Metastatic tumor masses involving the
myocardium and endocardium.
Cardiac
tumors
Primary tumors include:
• Myxoma: benign tumor, occurs
mainly in atria, left atrium in
about 80% of the cases. They
appear
as
sessile
or
pedunculated gelatinous mass
covered by endothelium. The
commonest 1ry adult heart
tumor.
– Microscopically:
multinucleated stellate (Starshaped) cells, edema and
mucoid stroma.
Cardiac tumors
• Rhabdomyoma
– Common (infancy and children)
– Associated with tuberous sclerosis (neurocutaneous
syndrome)
– Grossly: myocardial masses project into the
ventricular lumen (solitary or multifocal).
– Microscopically: eosinophilic polygonal cells (contain
large glycogen granules in their cytoplasm).
• Lipoma, and Papillary Elastofibromas,
• Sarcomas: Angiosarcomas, and Rhabdomyosarcomas.
Rhabdomyoma of the left
ventricle