NURS 4581 Exam 2– Nursing of Adults with Complex Needs -UTA Critical Care Exam 2: Dysrhythmias, Pacemakers, CAD/ACS, and Hemodynamic Monitoring

NURS 4581 Exam 2– Nursing of Adults with Complex Needs -UTA

Critical Care Exam 2: Dysrhythmias, Pacemakers,
CAD/ACS, and Hemodynamic Monitoring


Section 1: Basic Heart Information and ECG Interpretation
(10 questions)
1. The primary pacemaker of the heart is the:
A. AV node
B. Purkinje fibers
C. SA node
D. Bundle of His
Answer: C
Rationale: The SA node is the primary pacemaker, firing at 60–100 beats per minute.




2. The secondary pacemaker of the heart is the:
A. SA node
B. AV node
C. Purkinje fibers
D. Atrial muscle
Answer: B
Rationale: The AV node can pace at 40–60 beats per minute if the SA node fails.




3. Purkinje fibers can pace at which rate if upstream conduction is compromised?
A. 60–100
B. 40–60
C. 15–40
D. 0–15
Answer: C
Rationale: Purkinje fibers are the tertiary pacemaker with a rate of 15–40.

,4. The P wave represents:
A. Ventricular depolarization
B. Atrial depolarization
C. Ventricular repolarization
D. Atrial repolarization
Answer: B
Rationale: The P wave reflects atrial depolarization. An upright P wave indicates the
beat originated in the SA node.




5. The QRS complex represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. AV node conduction
Answer: B
Rationale: QRS represents ventricular depolarization – the ventricles "going to work."




6. The T wave represents:
A. Ventricular depolarization
B. Atrial repolarization
C. Ventricular repolarization
D. Atrial depolarization
Answer: C
Rationale: The T wave indicates ventricular repolarization – the ventricles "resting."




7. The normal PR interval is:
A. 0.12–0.20 seconds
B. 0.20–0.40 seconds
C. ≤0.12 seconds
D. 0.04–0.10 seconds
Answer: A
Rationale: Normal PR interval is 0.12–0.20 seconds, representing time for atrial
contraction and AV node conduction.

,8. The normal QRS duration is:
A. 0.12–0.20 seconds
B. ≤0.12 seconds
C. >0.12 seconds
D. 0.20–0.40 seconds
Answer: B
Rationale: Normal QRS is ≤0.12 seconds. A narrow QRS indicates atrial origin; a wide QRS
indicates ventricular origin.




9. Using the 6-second strip method, how is heart rate calculated?
A. Count the P waves and multiply by 10
B. Count the R waves and multiply by 10
C. Count the small boxes between R waves and divide by 1500
D. Count the QRS complexes and multiply by 6
Answer: B
Rationale: Count R waves in a 6-second strip and multiply by 10.




10. Using the small box method, how is heart rate calculated?
A. Count small boxes between R waves and multiply by 10
B. Count small boxes between R waves and divide by 1500
C. Count large boxes and multiply by 300
D. Count R waves and divide by 6
Answer: B
Rationale: Divide 1500 by the number of small boxes between two R waves.




Section 2: Sinus Rhythms
(8 questions)
11. Normal sinus rhythm (NSR) has a rate of:
A. <60
B. 60–100
C. >100
D. 40–60
Answer: B
Rationale: NSR rate is 60–100 bpm, regular rhythm, upright P waves, normal PR and
QRS.

, 12. Sinus bradycardia is defined as a rate:
A. <60 bpm
B. <50 bpm
C. <40 bpm
D. <30 bpm
Answer: A
Rationale: Sinus bradycardia is SA node firing slower than 60 bpm.




13. Sinus tachycardia is defined as a rate:
A. >80 bpm
B. >90 bpm
C. >100 bpm
D. >120 bpm
Answer: C
Rationale: Sinus tachycardia is SA node firing faster than 100 bpm.




14. Which characteristic confirms that a rhythm originated from the SA node?
A. Narrow QRS
B. Upright, rounded P wave consistent in shape and paired with QRS
C. Heart rate >100
D. PR interval >0.20 seconds
Answer: B
Rationale: Upright P waves indicate sinus origin; the rhythm name begins with "sinus."




15. A patient with sinus bradycardia is asymptomatic. The appropriate initial action
is:
A. Administer atropine
B. Apply transcutaneous pacemaker
C. Observe and monitor
D. Start dopamine infusion
Answer: C
Rationale: Asymptomatic bradycardia does not require treatment; observe and
monitor.