CHAPTER 4 ■
CARDIAC FUNCTION
89
5.
Left ventricular end-diastolic pressure is
increased by
a. Decreased afterload.
b. Decreased venous return.
c. Increased inotropy.
d. Ventricular hypertrophy.
6.
A 67-year-old male patient complains
of excessive shortness of breath during
exertion. The report from a follow-up
echocardiogram says that his left ven-
tricular stroke volume is 50 mL, with an
ejection fraction of 25%. Which of the
following statements is true concerning
this patient’s left ventricle?
a. End-diastolic volume is elevated
above normal.
b. End-systolic volume is less than normal.
c. Inotropy is increased.
d. Preload is reduced.
7.
A patient is experiencing an acute
hypertensive crisis. This large increase in
arterial pressure will have which of the
following direct effects on the heart?
a. Decrease left ventricular end-systolic
volume
b. Decrease the velocity of muscle fiber
shortening
c. Decrease ventricular preload
d. Increase stroke volume
8.
Increasing the inotropic state of the
myocardium will
a. Increase end-systolic volume.
b. Increase the width of the pressure-
volume loop.
c. Increase ventricular end-diastolic
volume.
d. Shift the force-velocity relationship to
the left.
9.
If each of the following is increased by 25%,
which one would cause the
smallest
change
in myocardial oxygen consumption?
a. Heart rate
b. Ventricular end-diastolic volume
c. Mean arterial pressure
d. Ventricular radius
ANSWERS TO REVIEW QUESTIONS
1.
The correct answer is “c” because the
mitral valve is open throughout ven-
tricular filling. Choice “a” is incorrect
because S4, when heard, is associated
with atrial contraction and frequently is
heard in hypertrophied hearts. Choice
“b” is incorrect because the aortic valve
is open only during ventricular ejec-
tion. Choice “d” is incorrect because the
ventricular pressure is higher than aortic
pressure only during the phase of rapid
ejection.
2.
The correct answer is “c” because aver-
age left atrial pressure is about 8 mm Hg
and average right atrial pressure is
about 4 mm Hg. Choice “a” is incorrect
because aortic diastolic pressure is about
80 mm Hg compared to a pulmonary
artery systolic pressure of 25 mm Hg.
Choice “b” is incorrect because left
atrial and left ventricular end-diastolic
pressures are normally higher than their
corresponding pressures on the right
side of the heart. Choice “d” is incorrect
because pulmonary artery diastolic pres-
sure is about 10 mm Hg, whereas right
atrial pressure is about 4 mm Hg.
3.
The correct answer is “c” because more
time is available for filling at reduced
heart rates (diastole is lengthened);
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