2024 CCRN CARDIOVASCULAR
PRACTICE EXAM QUESTIONS WITH
CORRECT ANSWERS
A patient with chest pain, dizziness, and shortness of breath is admitted to
the critical care unit. The monitor shows type II second-degree AV block with
a rate of 40 beats/min. The initial treatment for this patient's heart rhythm is
which of the following actions?
a. Administration of epinephrine 1 mg IV
b. Administration of adenosine (Adenocard) 6 mg IV
c. Application of transcutaneous pacemaker
d. Preparation of the patient immediately for insertion of an external
transvenous pacemaker - CORRECT-ANSWERSCorrect answer: c
Rationale: Transcutaneous pacing is the initial treatment of choice because
of the speed with which it can be instituted. Transvenous pacing is indicated
as soon as possible because of the potential discomfort of transcutaneous
pacing. Adenosine is given in supraventricular tachycardias and not slow
rhythms, and epinephrine would be used for asystole but not if the patient
has a rhythm and cardiac output. You may have considered atropine (though
it was not listed as an option), but it would have been contraindicated
because of the chest pain and, therefore, presumed myocardial ischemia
because it could cause significant tachycardia and an increase in myocardial
oxygen consumption.
Test-Taking Strategy: Eliminate option b because adenosine is used for
supraventricular tachycardias and not for bradycardias. Epinephrine is used
in pulseless situations, so eliminate option a. This patient does need a
pacemaker, so choose the one immediately available. Choose option c.
1A 52-year-old man has undergone coronary artery bypass grafting and has
returned to the critical care unit. During the last hour his parameters were as
follows:
O2 saturation 99%
PaO2 with FiO2 0.4 184 mm Hg Hemoglobin 12 gm/dL
Serum potassium 3.8 mEq/L
Urine output 100 mL/hr
Now the patient's venous oxygen saturation (SvO2) monitor shows a rapid
decline from a reading of 75% to 62% without any change in arterial oxygen
saturation (SaO2). His cardiac rhythm changes from normal sinus rhythm to
a sinus rhythm with ventricular bigeminy.
The nurse should first:
,a. check serum arterial blood gases.
b. administer 10 mEq potassium.
c. increase the FiO2.
d. check the serum potassium level. - CORRECT-ANSWERSCorrect answer: d
Rationale: Because the SaO2 has not changed, the drop in SvO2 most likely
is linked to the decrease in cardiac output caused by the ventricular ectopy.
The nurse's initial action would be to identify the cause so that treatment
can be directed toward that cause. Given the patient's urine output of 100
mL/hr, hypokalemia is a likely cause as a result of the high urine output
because, in most cases, potassium excretion is related directly to urine
output.
Test-Taking Strategy: Note that the assessment of arterial blood gases
(option a) and administration of additional oxygen (option c) seem to be
good answers, but the SaO2 has not changed. This indicates that the
decrease in SvO2 is due to a decrease in cardiac output or hemoglobin or an
increase in oxygen consumption at the tissue level. The last recorded
hemoglobin was acceptable, and there is no new evidence of bleeding.
Because of the recent onset of dysrhythmia, an additional drop in potassium
should be suspected but should be confirmed, so select option d.
A 52-year-old man has undergone coronary artery bypass grafting and has
returned to the critical care unit. During the last hour his parameters were as
follows:
O2 saturation 99%
PaO2 with FiO2 0.4 184 mm Hg Hemoglobin 12 gm/dL
Serum potassium 3.8 mEq/L
Urine output 100 mL/hr
Now the patient's venous oxygen saturation (SvO2) monitor shows a rapid
decline from a reading of 75% to 62% without any change in arterial oxygen
saturation (SaO2). His cardiac rhythm changes from normal sinus rhythm to
a sinus rhythm with ventricular bigeminy.
The nurse would assess the patient for which of the following?
a. Decreased cardiac output
b. Internal hemorrhage
c. Hypermetabolism
d. Hypoxemia - CORRECT-ANSWERSCorrect answer: a
Rationale: Mixed venous oxygen saturation is affected by four factors:
oxygen saturation, hemoglobin, cardiac output, and tissue extraction. In
evaluating this patient's decreased SvO2, the nurse has current information
for these factors except for cardiac output and tissue extraction.
Test-Taking Strategy: Of the given options, option a is the correct choice
because ventricular dysrhythmias commonly result in a decrease in cardiac
output. If you had no idea of a correct answer, cluster options b, c, and d as
noncardiac involvement, then select option a. The clinical situation is related
to the heart, so that would be a priority assessment.
, Four days after a mitral valve replacement, the patient develops atrial
fibrillation. The nurse initially would:
a. order a 12-lead electrocardiogram.
b. evaluate the patient for clinical indications of hypoperfusion.
c. notify the physician.
d. ask the patient to bear down as if having a bowel movement. - CORRECT-
ANSWERSCorrect answer: b
Rationale: The onset of atrial fibrillation results in the loss of atrial kick. Loss
of atrial kick may reduce the cardiac output by as much as 20-30%. This is
especially true in patients whose cardiac output may be affected by long-
standing cardiac disease, such as mitral valve disease. Assess the patient for
clinical indications of hypoperfusion (e.g., cool skin, decreased urine output,
narrowed pulse pressure, and hypotension).
Test-Taking Strategy: Remember always being told to treat the patient and
not the monitor? What that really means is that clinical assessment is always
indicated to evaluate the implications of the rhythm change. Always finish
your assessment before notifying the physician so that you have a complete
clinical presentation to describe. Eliminate option c. Ordering a 12-lead
electrocardiogram is a good option if you cannot interpret the rhythm from
the rhythm strip. This question indicates that the rhythm is clear, so the 12-
lead electrocardiogram is not the priority action, so eliminate option a.
Asking the patient to bear down will increase vagal stimulation. It may slow
down but usually will not cause conversion of atrial fibrillation, so eliminate
option d. Assessment is the priority in this question. Choose option b.
A patient is admitted to the coronary care unit with third-degree AV heart
block, and a transvenous temporary ventricular pacemaker is inserted. Four
hours later the patient complains of dizziness while lying in bed. The monitor
shows third-degree AV block with a ventricular rate of 52 beats/min and no
pacing spikes. This indicates which of the following?
a. Failure to capture
b. Failure to pace
c. Competition between pacemaker and intrinsic rhythm
d. Failure to sense - CORRECT-ANSWERSCorrect answer: b
Rationale: Return of the prepacemaker rhythm indicates a failure to pace. No
pacing spikes are evident.
Test-Taking Strategy: Failure to capture would be evidenced by pacing
spikes not followed by a QRS complex (or P wave if atrial pacer), so eliminate
option a. Failure to sense is evidenced by pacing spikes occurring on time
regardless of the patient's intrinsic rhythm, so eliminate option d. Failure to
sense causes competition between the pacemaker and the intrinsic rhythm,
so eliminate option c. Recall that no spikes equals no pacer activity. If there
is an intrinsic rate slower than the pacemaker rate, this would indicate a
malfunction referred to as failure to pace or failure to fire. Choose b.
PRACTICE EXAM QUESTIONS WITH
CORRECT ANSWERS
A patient with chest pain, dizziness, and shortness of breath is admitted to
the critical care unit. The monitor shows type II second-degree AV block with
a rate of 40 beats/min. The initial treatment for this patient's heart rhythm is
which of the following actions?
a. Administration of epinephrine 1 mg IV
b. Administration of adenosine (Adenocard) 6 mg IV
c. Application of transcutaneous pacemaker
d. Preparation of the patient immediately for insertion of an external
transvenous pacemaker - CORRECT-ANSWERSCorrect answer: c
Rationale: Transcutaneous pacing is the initial treatment of choice because
of the speed with which it can be instituted. Transvenous pacing is indicated
as soon as possible because of the potential discomfort of transcutaneous
pacing. Adenosine is given in supraventricular tachycardias and not slow
rhythms, and epinephrine would be used for asystole but not if the patient
has a rhythm and cardiac output. You may have considered atropine (though
it was not listed as an option), but it would have been contraindicated
because of the chest pain and, therefore, presumed myocardial ischemia
because it could cause significant tachycardia and an increase in myocardial
oxygen consumption.
Test-Taking Strategy: Eliminate option b because adenosine is used for
supraventricular tachycardias and not for bradycardias. Epinephrine is used
in pulseless situations, so eliminate option a. This patient does need a
pacemaker, so choose the one immediately available. Choose option c.
1A 52-year-old man has undergone coronary artery bypass grafting and has
returned to the critical care unit. During the last hour his parameters were as
follows:
O2 saturation 99%
PaO2 with FiO2 0.4 184 mm Hg Hemoglobin 12 gm/dL
Serum potassium 3.8 mEq/L
Urine output 100 mL/hr
Now the patient's venous oxygen saturation (SvO2) monitor shows a rapid
decline from a reading of 75% to 62% without any change in arterial oxygen
saturation (SaO2). His cardiac rhythm changes from normal sinus rhythm to
a sinus rhythm with ventricular bigeminy.
The nurse should first:
,a. check serum arterial blood gases.
b. administer 10 mEq potassium.
c. increase the FiO2.
d. check the serum potassium level. - CORRECT-ANSWERSCorrect answer: d
Rationale: Because the SaO2 has not changed, the drop in SvO2 most likely
is linked to the decrease in cardiac output caused by the ventricular ectopy.
The nurse's initial action would be to identify the cause so that treatment
can be directed toward that cause. Given the patient's urine output of 100
mL/hr, hypokalemia is a likely cause as a result of the high urine output
because, in most cases, potassium excretion is related directly to urine
output.
Test-Taking Strategy: Note that the assessment of arterial blood gases
(option a) and administration of additional oxygen (option c) seem to be
good answers, but the SaO2 has not changed. This indicates that the
decrease in SvO2 is due to a decrease in cardiac output or hemoglobin or an
increase in oxygen consumption at the tissue level. The last recorded
hemoglobin was acceptable, and there is no new evidence of bleeding.
Because of the recent onset of dysrhythmia, an additional drop in potassium
should be suspected but should be confirmed, so select option d.
A 52-year-old man has undergone coronary artery bypass grafting and has
returned to the critical care unit. During the last hour his parameters were as
follows:
O2 saturation 99%
PaO2 with FiO2 0.4 184 mm Hg Hemoglobin 12 gm/dL
Serum potassium 3.8 mEq/L
Urine output 100 mL/hr
Now the patient's venous oxygen saturation (SvO2) monitor shows a rapid
decline from a reading of 75% to 62% without any change in arterial oxygen
saturation (SaO2). His cardiac rhythm changes from normal sinus rhythm to
a sinus rhythm with ventricular bigeminy.
The nurse would assess the patient for which of the following?
a. Decreased cardiac output
b. Internal hemorrhage
c. Hypermetabolism
d. Hypoxemia - CORRECT-ANSWERSCorrect answer: a
Rationale: Mixed venous oxygen saturation is affected by four factors:
oxygen saturation, hemoglobin, cardiac output, and tissue extraction. In
evaluating this patient's decreased SvO2, the nurse has current information
for these factors except for cardiac output and tissue extraction.
Test-Taking Strategy: Of the given options, option a is the correct choice
because ventricular dysrhythmias commonly result in a decrease in cardiac
output. If you had no idea of a correct answer, cluster options b, c, and d as
noncardiac involvement, then select option a. The clinical situation is related
to the heart, so that would be a priority assessment.
, Four days after a mitral valve replacement, the patient develops atrial
fibrillation. The nurse initially would:
a. order a 12-lead electrocardiogram.
b. evaluate the patient for clinical indications of hypoperfusion.
c. notify the physician.
d. ask the patient to bear down as if having a bowel movement. - CORRECT-
ANSWERSCorrect answer: b
Rationale: The onset of atrial fibrillation results in the loss of atrial kick. Loss
of atrial kick may reduce the cardiac output by as much as 20-30%. This is
especially true in patients whose cardiac output may be affected by long-
standing cardiac disease, such as mitral valve disease. Assess the patient for
clinical indications of hypoperfusion (e.g., cool skin, decreased urine output,
narrowed pulse pressure, and hypotension).
Test-Taking Strategy: Remember always being told to treat the patient and
not the monitor? What that really means is that clinical assessment is always
indicated to evaluate the implications of the rhythm change. Always finish
your assessment before notifying the physician so that you have a complete
clinical presentation to describe. Eliminate option c. Ordering a 12-lead
electrocardiogram is a good option if you cannot interpret the rhythm from
the rhythm strip. This question indicates that the rhythm is clear, so the 12-
lead electrocardiogram is not the priority action, so eliminate option a.
Asking the patient to bear down will increase vagal stimulation. It may slow
down but usually will not cause conversion of atrial fibrillation, so eliminate
option d. Assessment is the priority in this question. Choose option b.
A patient is admitted to the coronary care unit with third-degree AV heart
block, and a transvenous temporary ventricular pacemaker is inserted. Four
hours later the patient complains of dizziness while lying in bed. The monitor
shows third-degree AV block with a ventricular rate of 52 beats/min and no
pacing spikes. This indicates which of the following?
a. Failure to capture
b. Failure to pace
c. Competition between pacemaker and intrinsic rhythm
d. Failure to sense - CORRECT-ANSWERSCorrect answer: b
Rationale: Return of the prepacemaker rhythm indicates a failure to pace. No
pacing spikes are evident.
Test-Taking Strategy: Failure to capture would be evidenced by pacing
spikes not followed by a QRS complex (or P wave if atrial pacer), so eliminate
option a. Failure to sense is evidenced by pacing spikes occurring on time
regardless of the patient's intrinsic rhythm, so eliminate option d. Failure to
sense causes competition between the pacemaker and the intrinsic rhythm,
so eliminate option c. Recall that no spikes equals no pacer activity. If there
is an intrinsic rate slower than the pacemaker rate, this would indicate a
malfunction referred to as failure to pace or failure to fire. Choose b.
