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U N I T 5
Circulatory Function
R E V I EW E X E R C I S E S
1.
A 40-year-old man presents in the emergency
department complaining of substernal chest pain
that is also felt in his left shoulder. He is short of
breath and nauseated. His blood pressure is 148/90
mm Hg and his heart rate is 110 beats/minute. His
ECG shows an ST-segment elevation with T-wave
inversion. He is given aspirin, morphine, and
oxygen. Blood tests reveal elevated CK-MB and
troponin I.
A.
What is the probable cause of the man’s
symptoms?
B.
Explain the origin of the left arm pain, nausea,
and increased heart rate.
C.
What is the significance of the ST-segment
changes and elevation in CK-MB and troponin
I?
D.
Relate the actions of aspirin, morphine, and
oxygen to the treatment of this man’s condition.
2.
A 50-year-old woman presents with complaints
of paroxysmal nocturnal dyspnea and orthopnea,
palpitations, and fatigue. An echocardiogram
demonstrates a thickened, immobile mitral valve
with anterior and posterior leaflets moving
together; slow early diastolic filling of the ventricle;
and left atrial enlargement.
A.
What is the probable cause of this woman’s
symptoms?
B.
Explain the pathologic significance of the slow
early diastolic filling, distended left atrium, and
palpitations.
C.
Given the echocardiographic data, what type of
cardiac murmur would you expect to find in this
woman?
D.
Which circulation (systemic or pulmonary)
would you expect to be affected as this woman’s
mitral valve disorder progresses?
3.
A 4-month-old male infant is brought into the
pediatric clinic by his mother. She reports that she
noted over the past several weeks that her baby’s
lips and mouth and his fingernails and toenails
have become a bluish-gray color. She also states
that he seems to tire easily and that even nursing
seems to wear him out. Lately, he has had several
spells where he has suddenly turned blue, has had
difficulty breathing, and has been very irritable.
During one of these spells he turned limp and
seemed to have passed out for a short time. An
echocardiogram reveals a thickening of the right
ventricular wall with overriding of the aorta,
a large subaortic ventricular septal defect, and
narrowing of the pulmonary outflow with stenosis
of the pulmonary valve.
A.
What is this infant’s probable diagnosis?
B.
Describe the shunting of blood that occurs
with this disorder and its relationship to the
development of cyanosis.
C.
The mother is instructed to place the infant in
the knee–chest position when he has one of the
spells in which he becomes blue and irritable.
How does this position help to relieve the
cyanosis and impaired oxygenation of tissues?
D.
The surgical creation of a shunt between the
aorta and pulmonary artery may be performed
as a palliative procedure for infants with
marked hypoplasia of the pulmonary artery,
with corrective surgery performed later in
childhood. Explain how this procedure increases
blood flow to the lungs.
R E F E R E N C E S
1. Gaziano TA, Gaziano JM. Global burden of cardiovascular
disease. In: Bonow R, Mann DL, Zipes DP, et al., eds.
Braunwald’s Heart Disease: A Textbook of Cardiovascular
Medicine
. 9th ed. Philadelphia, PA: Saunders Elsevier;
2012:1–22.
2. Moore KL, Dalley AF, Agur AMR.
Clinically Oriented Anatomy
.
6th ed. Philadelphia, PA: Wolters Kluwer Health | Lippincott
Williams & Wilkins; 2010:144–148.
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Congenital heart defects are commonly
classified according to anatomic site (e.g.,
atrial or ventricular septal), hemodynamic
alterations (shunting of blood), and their effect
on pulmonary blood flow and tissue oxygenation
(noncyanotic, cyanotic).
■■
Hemodynamic alterations may produce shunting
of blood from the right to the left or from the left
to the right side of the heart, with the direction
and degree of shunt depending on the size and
position of the defect that connects the two sides
of the heart and the difference in resistance
between the two sides of the circulation. Left-to-
right shunts typically increase the volume of the
right side of the heart and pulmonary circulation,
and right-to-left shunts transfer deoxygenated
blood from the right side of the heart to the left
side, diluting the oxygen content of blood that is
being ejected into the systemic circulation and
causing cyanosis.
■■
Kawasaki disease is an acute vasculitis of young
children that affects the skin, brain, eyes, joints,
liver, lymph nodes, and heart.The disease can
produce aneurysmal disease of the coronary
arteries and is the most common cause of
acquired heart disease in young children.
SUMMARY CONCEPTS
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