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Essentials of Pathophysiology
CHAPTER 19
DISORDERS OF CARDIAC FUNCTION
PRE-LECTURE QUIZ
F
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Pericarditis represents an inflammatory process of
the myocardium.
All types of angina represent an acute myocardial
infarction, also known as a heart attack.
The heart extracts and uses 60% to 80% of the
oxygen in blood flowing through the coronary
arteries.
Atherosclerosis is by far the most common cause of
coronary heart disease.
Stable atherosclerotic plaques tend to rupture more
than unstable atherosclerotic plaques and lead to
acute coronary syndromes, ranging from unstable
angina to ST-segment elevation myocardial
infarction.
PRE-LECTURE QUIZ

Cardiac __________ is a life-threatening, slow or rapid
compression of the heart due to the accumulation of
fluid, pus, or blood in the pericardial sac.

Rheumatic heart disease, a disorder that follows a
group A _____________ throat infection, is of great
concern because of the potential effects of chronic
valvular disorders that produce permanent cardiac
dysfunction and sometimes fatal heart failure years
later.
__________ refers to a narrowing of the valve orifice and
failure of the valve leaflets to close properly.
corornary
Markers
Stenosis

Streptococcal

Creatine kinase, myoglobin, and troponin are known as
serum cardiac __________ and are useful for acute
myocardial infarction determination and classification.

Coronary heart disease is a disorder of impaired
__________ blood flow, usually caused by
atherosclerosis.
Tamponade
DISORDERS THAT AFFECT THE WHOLE HEART

Pericardial disorders

Coronary heart disease

Myocardial diseases

These disorders can cause symptoms of both rightand left-sided heart failure
THE PERICARDIUM SURROUNDS THE HEART
PERICARDITIS

Inflammation of the pericardium causes:
 Pain
 Exudate
º
Serous  pericardial effusion

º
Cardiac tamponade: rapid accumulation of exudate
compresses the heart
Fibrous  friction rub; adhesions
 ECG
changes
PERICARDITIS (CONT.)

Inflammation of the pericardium may restrict the
heart’s movement due to:
 Serous exudate filling the pericardial cavity
(pericardial effusion)
 Fibrous scar tissue making the pericardium
stick to the heart (constrictive pericarditis)
CONSEQUENCES OF
PERICARDIAL
EFFUSION
fluid in pericardial
cavity
restricts heart
expansion
left ventricle
cannot accept
enough blood
right ventricle
cannot accept
enough blood
decreased
cardiac
output
increased venous
pressure; jugular
distension
decreased blood
pressure and
shock
QUESTION
What is the immediate treatment for severe
cardiac tamponade?
a. Oxygen
b. Cardiac drugs
c. Surgery
d. Pericardiocentesis (removal of fluid from the
sac with a needle)
PERICARDITIS

Inflammation of the pericardium causes:
 Pain
 Exudate
º
Serous  pericardial effusion

º
Cardiac tamponade: rapid accumulation of exudate
compresses the heart
Fibrous  friction rub; adhesions
 ECG
changes
PERICARDITIS (CONT.)

Inflammation of the pericardium may restrict the heart’s
movement due to:
 Serous exudate filling the pericardial cavity (pericardial
effusion)
 Fibrous scar tissue making the pericardium stick to the
heart (constrictive pericarditis)
CONSEQUENCES OF
PERICARDIAL
EFFUSION
fluid in pericardial
cavity
restricts heart
expansion
left ventricle
cannot accept
enough blood
right ventricle
cannot accept
enough blood
decreased
cardiac
output
increased venous
pressure; jugular
distension
decreased blood
pressure and
shock
QUESTION
What is the immediate treatment for severe
cardiac tamponade?
a. Oxygen
b. Cardiac drugs
c. Surgery
d. Pericardiocentesis (removal of fluid from the sac with a
needle)
ANSWER
Pericardiocentesis (removal of fluid from the
sac with a needle)
Rationale: In severe cardiac tamponade, there is
so much fluid in the pericardial sac
compressing the heart that its function
declines rapidly. The fluid must be removed
quickly by inserting a needle into the
pericardial space and aspirating the
accumulated fluid.
d.
PULSUS PARADOXUS
On inhaling, the right
ventricle fills with extra
blood
 When the right ventricle
is overfilled, the left
ventricle is compressed
and cannot accept much
blood. Because the
heart cannot fully
expand
 On the next heartbeat,
the left ventricle does
not send out much
blood: systolic BP drops

CORONARY HEART DISEASE


Atherosclerosis blocks coronary arteries
Ischemia may cause:
 Angina
 Heart attack
 Cardiac arrhythmias
 Conduction deficits
 Heart failure
 Sudden death
Plaque/Thrombus Formation

CHRONIC ISCHEMIC HEART DISEASE

Imbalance in blood supply and the heart’s
demands for oxygen
 Less
blood
º
Atherosclerosis
º
Vasospasm
º
Thrombosis
 Higher
oxygen demand
º
Stress
º
Exercise
º
Cold
KINDS OF ANGINA



Stable angina
 Pain when heart’s oxygen demand increases
Variant angina
 Pain when coronary arteries spasm
Silent myocardial ischemia
 Myocardial ischemia without pain
ACUTE CORONARY SYNDROMES


ECG changes
 T-wave inversion
 ST-segment depression or elevation
 Abnormal Q wave
Serum cardiac markers
 Proteins released from necrotic heart cells
º Myoglobin, creatine kinase, troponin
QUESTION
Tell whether the following statement is true or
false.
Chronic ischemic heart disease is more likely to
result in stable angina than acute coronary
syndromes.
ANSWER
True
Rationale: Ischemic heart disease is
characterized by stable angina, which is
associated with plaques that are fixed
obstructions. Unstable angina is characterized
by plaques with platelets stuck to them (these
are likely to form a thrombus)—they cause a
range of acute coronary syndromes.
ACUTE MYOCARDIAL INFARCTION



Chest pain
 Severe, crushing, constrictive, OR like
heartburn
Sympathetic nervous system response
 GI distress, nausea, vomiting
 Tachycardia and vasoconstriction
 Anxiety, restlessness, feeling of impending
doom
Hypotension and shock
 Weakness in arms and legs
AN ACUTE MI (AMI) LEAVES BEHIND AN AREA
OF YELLOW NECROSIS
COMPLICATIONS OF AMI

Heart failure

Cardiogenic shock

Pericarditis

Thromboemboli

Rupture of the heart

Ventricular aneurysms
MALFUNCTIONING HEART MUSCLE

Malfunctioning heart muscle can cause heart
failure if:
 Ventricles are unusually thick so there is not a
normal amount of room for blood inside them
(hypertrophic cardiomyopathy)
 Ventricles are too stiff to stretch (restrictive
cardiomyopathy)
 Ventricles are too weak to pump out the blood
that is in them (MI, myocarditis, dilated
cardiomyopathy)
MYOCARDIAL DISORDERS


Myocarditis
Cardiomyopathies
 Dilated cardiomyopathies
 Hypertrophic cardiomyopathies
 Restrictive cardiomyopathies
 Peripartum cardiomyopathy
HYPERTROPHIC CARDIOMYOPATHY



Defects in their
contractile proteins
make cells too weak
They hypertrophy to
do the same amount
of work as normal
cells
Need more oxygen
and perform less
efficiently, so the
person is prone to
heart failure and may
suffer sudden death
during exertion
QUESTION
Which type of cardiomyopathy is characterized by
weakened ventricles?
a. Dilated cardiomyopathy
b. Hypertrophic cardiomyopathy
c. Restrictive cardiomyopathy
d. Peripartum cardiomyopathy
ANSWER
Dilated cardiomyopathy
Rationale: In dilated cardiomyopathy, the
ventricles are too weak to pump blood,
resulting in a diminished cardiac output (CO).
The other types listed are caused by thick
ventricles, stiff ventricles, or LV dysfunction in
late pregnancy or postpartum, respectively.
a.
VALVULAR DISORDERS AND HEART DEFECTS

By
interfering
with normal
blood flow,
these often
cause the
signs and
symptoms of
left- or rightsided heart
failure
body
left
heart
right
heart
lungs
THE ENDOCARDIAL STRUCTURES

The endocardial structures lining the heart can
cause heart failure
 If the AV valves leading into the ventricles do
not work (mitral or tricuspid problems)
 If the semilunar valves leading out of the
ventricles do not work (aortic or pulmonary
problems)
CARDIAC CYCLE
Discussion:
Arrange these steps in the proper order:
4 – First heart sound
6 – Ventricles relax
5 – Semilunar valves open
1 – Start Systole
10 – End Diastole
3 – AV valves close
9 – AV valves open
7 – Semilunar valves close
2 – Ventricles contract
8 – Second heart sound
VALVE DEFECTS

Each of the four valves can be defective

Stenosis: valve will not open all the way; it is harder
to force blood through it

Regurgitation: valve will not close all the way; it
leaks when it should be closed
Also called valvular insufficiency
QUESTION
Tell whether the following statement is true or
false.
Mitral valve regurgitation results in a diminished
stroke volume.
ANSWER
True
Rationale: If the mitral valve does not close as it
should, a portion of the stroke volume (amount
of blood ejected by the ventricle/beat) leaks
back into the left atrium, decreasing the
amount of blood that is ejected during that
beat (SV).
DISCUSSION
Defects in which valves might cause:
 Severe dependent edema?
 Paroxysmal nocturnal dyspnea?
 Congested liver?
 Distended jugular veins?
 Productive cough with frothy sputum?
IDENTIFYING DEFECTIVE VALVES
The blood going through the valve makes a
noise
 These are called heart murmurs
 You can identify them by:

Where they are—which valve are they near?
 How they sound—high- or low-pitched?
 When they happen—systole or diastole?

WHEN WILL YOU HEAR MURMURS?

If a valve is stenotic, you
will hear a murmur of
blood shooting through
the narrow opening
when the valve is open

If a valve is regurgitant,
you will hear a murmur
of blood leaking back
through when the valve
should be closed
LEFT-SIDED VALVULAR DISORDERS


Mitral valve disorders
 Mitral valve stenosis
 Mitral valve regurgitation
 Mitral valve prolapse
Aortic valve disorders
 Aortic valve stenosis
 Aortic valve regurgitation
Valvular Disorders
•Mitral Regurgitation
•Part of SV goes back
into the LA
•Heart has to work
harder to meet body
needs
•LV hypertrophy
•Aortic Regurgitation
•Blood flows
backward into the LV
from the Aorta
•LV Dilatation
•Aortic Valve Stenosis
•Aortic valve is constricted
•Difficult to pump blood
from the LV
•LV hypertrophy
•Mitral Stenosis
•Incomplete LV filling
•Lower CO
CONGENITAL HEART DEFECTS

Atrial septal defects

Ventricular septal defects

Endocardial cushion defects

Patent ductus arteriosus

Pulmonary stenosis

Tetralogy of Fallot

Transposition of the great vessels

Coarctation of the aorta
SHUNTS



A shunt is an opening or connection that lets
blood move from one side of the circulation to
the other
Most shunts occur in the heart and move blood
either from the left to the right or from the right
to the left
Because the left side is stronger, blood is
usually pushed from the left to the right side
SHUNTS (CONT.)




Shunts are normal before birth
Foramen ovale
 Lets blood go from the right atrium to the left
atrium to bypass the lungs
Ductus arteriosus
 Lets blood go from the pulmonary trunk to the
aorta to bypass the lungs
Ductus venosus
 Lets blood go from the visceral veins to the
vena cava, bypassing the liver
LEFT-TO-RIGHT SHUNT
body
right
heart
Less blood
goes to body
Blood moves from left
left to right heart
More blood
goes to lungs
lungs
RIGHT-TO-LEFT SHUNT
body
right
heart
Deoxygenated
blood goes to
body
Blood moves from
right to left
Less blood goes
to lungs
lungs
left
heart
DISCUSSION
Show how the diagram would
look for:
 Patent ductus arteriosus
body
left
heart
right
heart
lungs
DISCUSSION
Show how the diagram would
look for:
 Transposition of the great
vessels
body
left
heart
right
heart
lungs
DISCUSSION
Show how the diagram would
look for:
 Tetralogy of Fallot
body
left
heart
right
heart
lungs