PATHOLOGY OF THE HEART
 ISCHEMIC HEART DISEASE (= CORONARY HEART DISEASE )
=group of closely related clinical syndromes that result from
myocardial ischemia
ischemic heart disease is a common cause of death
- imbalance between myocardial oxygen demand and supply
could be caused by three possible mechanisms:
1) reduced coronary blood flow- coronary atherosclerosis,
superimposed by thrombosis, vasospasm and aggregation of platelets
can contribute to the ischemia
2) increased myocardial demand-due to tachycardia, myocardial
hypertrophy,etc
3) diminished oxygen transport- severe anaemia, advanced lung
disease, congenital cyanotic HD, carbon monoxide poisoning, cigarette
smoking
ISCHEMIC HEART DISEASE
-four different
distinguished:
syndromes
of
ischemic
heart
disease
can
be
1) angina pectoris
2) myocardial infarction
3) chronic ischemic heart disease
4) sudden death
 1) ANGINA PECTORIS
- characterized by attacks of chest pain due to myocardial ischemia
- angina pectoris is caused by atherosclerosis and stenosis of the
coronary arteries, that can provide adequate blood supply to the
myocardium at rest, but not enough in exercise -thus an increased
effort, stress, increased demand provoke pain (administration of
nitroglycerin causes a relief)
 2) ACUTE MYOCARDIAL INFARCTION
-is ischemic necrosis of myocardium
-Myocardial infarction could be subdivided into two types with
different morphology, pathogenesis and clinical significance :
1-subendocardial- is limited to the inner one third or one half of
ventricular wall-subendocardium is most vulnerable to any reduction
of blood flow
-often occurs in global ischemia due to diffuse severe coronary
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AS but without superimposed thrombosis- transient global borderline
perfusion made critical by an increased demand, vasospasm or
hypotension
2-transmural- necrosis involves the full thickness of the heart wall
-virtually all IM involve left ventricle, and interventricular septum
grossly: occlusive thrombus can usually, but not always be identified
in the coronary artery
microscopically: the appearance of IM changes with time-2h- no changes
-3-6h- changes may be visualized by the use of histochemic
techniques, such as staining for dehydrogenases
-more than 3h- early electron microscopic changes
-6-8h- early light microscopic changes and after 24h- first
macroscopic changes
 morphologic complications associated with IM:
- papillary muscle infarction may cause a rupture and acute
insufficiency of mitral valve
- fibrinous and fibrinohemorrhagic pericarditis
- mural thrombosis
- rupture of the heart in the area of IM- causes massive cardiac
tamponade
- chronic ventricular aneurysm
 3) CHRONIC ISCHEMIC HEART DISEASE
= chronic progressive coronary atherosclerosis and progressive
ischemic myocardial damage
morphology: modest left ventricular dilatation, atherosclerosis of
coronary arteries, and myofibrosis
clinical course: slowly progressive disease- serious cardiac arrhythmia
or IM may develop
 4) SUDDEN CARDIAC DEATH
= unexpected death from cardiac causes within 1-24h after the onset
of acute symptoms
-mechanism- malignant arrhytmia caused by ischemia
 CONGENITAL HEART DISEASES (CHD)
Etiology:
-in most cases of CHD -no identifiable cause
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-they are very
environmental inputs
likely
multifactorial
with
genetic
and
-in few patients, a specific cause can be identified, such as
transplacental infection of the fetus by rubeola virus (1st trimester)
-chromosomal abnormalities may be associated with CHD- high
incidence of defects of the atrioventricular valves in Down syndrome
-some drugs, such as thalidomide were shown to cause severe
defects in the fetus including cardiac anomalies
-fetal alcohol syndrom- due to high amounts of alcohol used
during early pregnancy
 CLASSIFICATION OF CHD:
-congenital heart anomalies are of two major types- shunts and
obstructions
 shunts= abnormal communications between heart chambers,
between large vessels or between chambers and vessels
Common defects are classified according to:
1- which side of the heart is involved
2- whether there is a communication (shunt) between both sides
3- in the defect with shunt, if there is a cyanosis (= a bluish
color of the skin and mucous membranes caused by increased
amount of reduced hemoglobin in arterial blood
 obstruction= typically coarctation, valvular stenoses (partial
occlusion) and atresias (complete occlusion). These do not cause
cyanosis
according to the major functional disorders, the CHD may be
classified to three categories:
 1 ) CHD with left-to-right shunts (=CHD with late cyanosis )
- these include interventricular and septal defects and patent
ductus arteriosus
-at early stage - these anomalies are without cyanosis, but the
increased blood pressure in right side induces chronic right heart
overload with pulmonary hypertension and right ventricle hypertrophy
- results in reversal of the direction of blood flow-leads to a
development of right-to-left shunt- means that unoxygenated blood is
then shunted to the left heart-which causes „ late cyanosis“
1. ATRIAL SEPTAL DEFECTS
-is characterized by an abnormal opening in the atrial septum that
allows free communication of blood
- when less than 1 cm, it is well tolerated, even larger ASDs are
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usually not detected until adult life, the problems appear with the
reversal of the blood flow and cyanosis and right-sided heart failure
2. VENTRICULAR SEPTAL DEFECTS
-is an abnormal opening in the ventricular septum that allows free
communication between left and right ventricles
- are among the most common CHD
clinical significance of ventricular septal defects ( VSD) depends on the
size of defect
-large VSD are much serious with clinical manifestation in early
life- strong left-to-right shunt causes an increased blood flowpulmonary hypertension- narrowing of the pulmonary arteries
-small VSD - mild left-to-right shunt does not cause changes in
blood flow, but the patients are in increased risk of infective
endocarditis
- surgical correction is advocated before right heart overload and
vascular pulmonary disease develop
3. PATENT DUCTUS ARTERIOSUS
- in the fetus, the ductus arteriosus is a normal fetal vascular channel
that connects the pulmonary artery and the aorta - permitting to bypass the inactive fetal lungs
- after the birth, the ductus closes spontaneously by muscle spasm
within 1 to 2 days of life
clinical significance:
-even large PDA are initially asymptomatic, but later they cause
a left-to-right shunt, pulmonary hypertension- reversal of blood flow,
right-sided hypertrophy and right-sided heart failure
- early surgical closure of a PDA is advocated
 2 ) CHD with right-to-left shunts (=CHD with early cyanosis)
- these include tetralogy of Fallot,
transpositions of large heart arteries
truncus
arteriosus
and
- secondary finding in long-standing cyanotic HD induce clubbing of
the fingers and toes, hypertrophic osteopathy and polycytemia
1. TETRALOGY OF FALLOT
-is the most common cyanotic CHD
 -it is characterized by
-large ventricular septal defects
-dextroposed aorta overriding the ventricular septal defect
-stenosis of the pulmonary tract with RV outflow obstruction
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-hypertrophy of the right ventricle
Cyanosis is present from birth-because the stenosis of pulmonary
artery causes right-to-left shunt from the very beginning (early
cyanosis) -„blue babies“
severity of clinical symptoms is directly related to the extent of RV
outflow obstruction
- mild pulmonic stenosis and large VSD produces only mild leftto-right shunt without cyanosis
- more severe pulmonary stenosis produces a cyanotic right-toleft shunt, right-sided hypertension appears-causing right-to left
shunt with hypoxemia, dyspnea, and cyanotic or hypoxic symptomsfinely pulmonary hypertension appears
-with complete pulmonic obstruction, survival is permitted only
by blood flow through a patent ductus arteriosus
 prognosis is very poor without treatment-surgical repair or at least
partial correction is now possible in all cases
 3 ) CHD with obstruction of blood flow without cyanosis
these include coarctation of the aorta, aortic valvular stenosis and
pulmonary valvular stenosis
1. COARCTATION OF THE AORTA
=represents narrowing or stenosis of the aorta
 clinical manifestation
obstruction-
depends
on
location
and
severity
of
two types of the coarctation of the aorta
 preductal type of coarctation - manifests early in life and may cause
rapid death
-survival depends on the ability of the ductus arteriosus to sustain
blood flow to the distal aorta and to the lower body adequately- even
then- severe lower body cyanosis- often associated with fetal RV
hypertrophy and early right heart failure
 postductal type -the „adult type“ because this type of anomaly is
generally asymptomatic untill adult life
-it usually leads to hypertension in the upper extremity, but weak
pulses and low blood pressure in the lower extremities- causes arterial
insufficiency-often claudications and coldness of the lower extremity
-collateral flow around stenosis of the aorta develops- with mammary
and axillary arteries dilatation
surgery: if untreated- life span is 40 years- death is due to aortic
dissection proximal to coarctation, intracranial hemorrhage, or
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infective endocarditis at the site of narrowing surgical resection of the
affected portion of the aorta and replacement by a prosthetic graft prevents these complications
ENDOCARDIAL AND VALVULAR DISEASES
among acquired valvular diseases, the most important are
1) CALCIFIC AORTIC VALVE STENOSIS
=represents 90% of acquired aortic stenoses, these are
degenerative, age-related lesions etiologically associated with AS,
morphology:
grossly- calcified masses within the sinuses of Valsalvae, that cause
thickening and fibrosis of the aortic valve with narrowing of the orifice
clinically: CHF due to LV hypertrophy and ischemia- because the
process may cause a narrowing of proximal parts of coronary arteries
2) POSTRHEUMATIC HEART DISEASE ( RHD)
-results from consequencies of acute rheumatic fever= is an acute
nonsuppurative inflammatory immune-mediated disease that follows
2-3 weeks after acute streptoccocal pharyngitis
-acute bacterial infection initiates a production of antibodies
that cross react with myocardial and endocardial cells and with other
cells of the body- resulting in a process of autoimmune tissue
destruction
-in acute rheumatic fever - many organs may be affected,
including

the heart- all layers may be involved
in myocardium- acute myocarditis- characterized by presence of
Aschoff bodies- composed of focal fibrinoid necrosis of collagen,
scattered lymphocytes and plasma cells and Aschoff giant epithelioid
histiocytes
in the endocardium- the disease affects particularly the valves- in
acute inflammation- the involved valves show edema, endocardial
damage and rheumatic vegetations (composed of fibrin and platelets,
and debris), in chronic phase- rheumatic endocarditis heals by
fibrosis- Mc Callum patch= focal fibrotic scar of the free endocardium
in the posterior wall of the left atrium
-fibrosis of the affected valve- causes a narrowing of the orifice=
valve stenosis
or severe destruction of the valve-may cause rigid dilatation=valve
incompetence
-the mitral valve is most commonly affected (aortic valve, less
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often the valves of right heart)
the joints - infection affects mostly large joints, tend to migrate from
joint to joint
basal ganglia of the brain- causes so called chorea- involuntary
movements
skin lesions subcutaneous rheumatic nodules- consist of fibrinoid
necrosis surrounded by a rim of granulation inflammatory reaction
3) INFECTIVE ENDOCARDITIS
-colonization of heart valves with microbes in severe bacteriemia
leads to formation of friable infected thrombi (vegetations) and to
destruction of the valve
ACUTE INFECTIVE ENDOCARDITIS
caused by highly virulent agents that can even attack previously
normal valves-severe bacteriemia
-large vegetations cause embolic complications with metastatic
abscesses in many organs. The disease typically presents as a rapidly
developing fever with rigor and severe weakness

SUBACUTE INFECTIVE ENDOCARDITIS
more common, caused by organisms with lower virulence, infection
usually affects previously damaged valves (chronic RHD, CHD,
prosthetic valves, degenerative valve diseases)
clinically low grade bacteriemia, fever. This disease tends to have a
protracted course.
morphology:
damaged valves are covered by infected thrombi (=vegetation)- consist
of collections of leukocytes, bacterial colonies, fibrin, cellular debris
-vegetations- are large, soft, friable, possible subject of
embolism- systemic embolism- infarction in the brain, kidney, spleen
mycotic aneurysm= infected embolus causes weakening of the affected
artery wall- formation of the aneurysm= miliary microabscesses
clinically:
-bacteriemia- blood culture positive for bacteria
-fever-most common feature
-splenomegaly-due to activation in chronic bacteriemia
(phagocytic and endothelial cell hyperplasia in the spleen)
-valvular dysfunction- cardiac
myocardium (abscess, perforation)
murmurs
or
injury
to
-systemic embolism -spleen, kidney, brain- including the
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metastatic infections
MYOCARDIAL DISEASES.
-diffuse heart disease can be separated to two major groups
1) myocarditis - diffuse diseases of the heart characterized by
inflammatory reaction
2) cardiomyopathy -diffuse non-inflammatory myocardial diseases
MYOCARDITIS
=inflammatory disease of the myocardium characterized by
rapid onset of clinical symptoms, such as arrhythmias or various ECG
changes
-usually most patients recover quickly but in some of them
years later, chronic heart failure (due to dilated cardiomyopathy)
-most cases are of viral origin - particularly coxsackie viruses,
influenza, cytomegalovirus- cardiac involvement occurs several days
to a few weeks after a primary virus infection at another site
-noninfectious myocarditis- may be immune mediated, for
example myocarditis associated with rhematic fever, SLE, drug
allergies, sarcoidosis
-idiopathic myocarditis- no infectious agent is found
giant cell myocarditis, Fiedler myocarditis
-rarely of bacterial origin- often secondary in patients with
bacteriemia (staphylococcal)
in severe cases of myocarditis- chronic heart failure due to dilated
cardiomyopathy develops
 CARDIOMYOPATHY
=the term implies a noniflammatory diffuse myocardial disease that is
not related to pressure or blood volume overload, not included
rheumatic heart disease, ischemic heart disease, congenital diseases
etc.
cardiomyopathy can be divided into three clinicopathologic categories:
1) dilated (congestive) CMP
2) hypertrophic CMP
3) restrictive ( obliterative ) CMP
 1) Dilated
CMP
-is characterized by marked gradual heart chamber dilatation
and hypertrophy with an disorder in contractile function that lack any
signs of myocarditis
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- the clinical course is slow and progressive to CHF
- dilated CMP represents the end stage of a variety of myocardial
disorders- such as -the heart damaged by viral infection- end stage of
viral injury to myocardium
CMP due to chronic alcohol abuse- alcohol has been shown to induce
regression changes within the myocardium - attributed to direct
toxicity of alcohol or to chronic thiamine deficiency
CMP due to cardiotoxic drugs, including adriamycin, daunorubicin,
heavy metal, such as cobalt and lithium)
clinical course:
-prognosis is poor, because dilated CMP represents a
progressive chronic heart disease with poor contraction ability and
markedly reduced cardiac output
-death due to fatal arrhythmia or of systemic embolism from
mural thrombi, or of progressive CHF
2) HYPERTROPHIC CMP -is characterized by subaortic septal
thickening that causes narrowing of the aortic outflow
-the disease may be familial and is transmitted by autosomal
dominant inheritence
morphology:- cardiac enlargment (great increase in weight) disproportionate myocardial hypertrophy -most evident in the left
ventricle and interventricular septum
-on cross section- the left ventricular cavity may be compressed by
hypertrophic septum into the banana-like shape, bulging septum into
the left ventricle cavity
clinically: hypertrophic CMP occurs most often in young adults- there
is an increased risk of sudden death
-the course of hypertrophic CMP is highly veriable
most patients with mild CMP improve or remain unchanged for years,
only in minority of patients the course is rapid
3) RESTRICTIVE (OBLITERATIVE) CMP - is the least common type
of CMP
is heterogenous group of diseases, such as cardiac amyloidosis,
sarcoidosis, endocardial fibroelastosis, endomyocardial fibrosis and
Loeffler endocarditis
common to all: -reduced ventricular elasticity and reduced diastolic
filling of the heart chambers and thus reduced cardiac output
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PERICARDIAL DISEASES
- almost always associated with disease in the heart, rarely pericardial
involvement may occur as a primary process
Accumulation of fluid in pericardial sac may include
1.) pericardial effusion
2.) hemopericardium
3.) pericardial exudate
 1.) pericardial effusion-the normal pericardial sac contains 30 to
50 ml of serous fluid non-inflammatory fluids
serous-most common form
-serosa is smooth and glistening,
-fluid accumulates slowly and therefore it is well tolerated untill
very large amount about 500 ml is formed
most common causes
hypoproteinemia
are
congestive
heart
failure
or
in
 2.) hemopericardium- accumulation of blood in the pericardial sac
without inflammatory component
most common causes are
- rupture of myocardium in IM
- follows trauma
- rupture of the intrapericardial part of the aorta
- or due to hemorrhage from the cancer metastases
200-300 ml may cause death- because the blood escapes rapidly and
produces cardiac tamponade
 3.) pericardial exudate- due to inflammation
-usually secondary to disorders involving the heart (IM, trauma,
tumors) or due to systemic diseases (uremia, autoimmune diseases)
 acute pericarditis
serous- in rheumatic fever, uremia, tumors, SLE, primary viral origin
-the fluid resorbs completely without any residues
fibrinous or sero-fibrinous- the most common form, typically occurs in
IM
-exudate may be completely resolved or be organized leaving typically
delicate, stringy adhesions= adhesive pericarditis
purulent- in fungal, bacterial or parasitic infections
-presents with prominent fever, rigors, fraction rub usually organizes
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and may produce constrictive pericarditis
hemorrhagic-denotes an exudate admixed with blood
-most commonly associated with TBC or cancer
-may organize by collagen formation with secondary hyalinization and
dystrophic calcification
caseous pericarditis- due to TBC usually by direct extension from
infected lymph nodes
 chronic pericarditis
adhesive- fibrous plaques („milk spots“) on the visceral pericardium or
adhesions between both two layers of the pericardium
-pericardial sac may be obliterated, the heart contracts with
difficulties- results in heart hypertrophy and dilatation
constrictive- uncommon chronic pericarditis, that is finally
characterized by encasement of the heart in a greatly thickened
fibrotic pericardium
-the pericardial sac is complitely obliterated -reduced is right atrial
filling- elevation of blood pressure in large veins -results in enlargment
of the liver and ascites
 TUMORS OF THE HEART AND PERICARDIUM
1) Cardiac myxoma - is a benign tumor of the endocardium- very
rare, occurs almost entirely in the atria
-is composed of small stellate cells embedded in an abundant myxoid
extracellular matrix
clinical features: -include fever, weight loss, anemia ( unexplained)
-systemic embolism, heart murmur, possible cause of sudden
unexpected death due to an acute prolapse of the tumor mass into
atrioventricular orifice which causes acute obstruction of circulation
2) Rhabdomyoma - the most common primary heart tumor in
children (very rare)
grossly- gray-whitish ventricular mass
microscopically- composed of large polygonal eosinophilic cells of
stellate shape- „spider cells“
secondary tumors of the heart- more common (site of primary
tumor- ca of lungs, breast, malignant melanoma, lymphoma,
leukemia)
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