regular rhythm, a P wave before every QRS complex, a PR interval of
0.16 second, and a QRS duration of 0.08 second. How should the
nurse interpret this rhythm?
A. Normal sinus rhythm
B. Sinus tachycardia
C. Junctional rhythm
D. Atrial flutter
Answer: A
Explanation: Normal sinus rhythm is identified by a regular rate of 60–
100 beats/min, one upright P wave before each QRS complex, a PR
interval of 0.12–0.20 second, and a QRS duration of less than 0.12
second.
2. A client has a heart rate of 48 beats/min with otherwise normal
sinus rhythm. Which rhythm is present?
A. Atrial fibrillation
B. Sinus bradycardia
C. Ventricular tachycardia
D. Junctional rhythm
Answer: B
Explanation: Sinus bradycardia is a sinus rhythm with a heart rate
below 60 beats/min. It may be normal in athletes but can also occur
with medications or conduction abnormalities.
, 3. Which client is most likely to develop sinus tachycardia?
A. A client with hypovolemia and fever
B. A client sleeping comfortably
C. A trained marathon runner
D. A client with complete heart block
Answer: A
Explanation: Fever, hypovolemia, anxiety, exercise, pain, and hypoxia
commonly increase sympathetic stimulation, producing sinus
tachycardia.
4. Which ECG characteristic is expected with atrial fibrillation?
A. Saw-tooth flutter waves
B. Irregularly irregular rhythm with no distinct P waves
C. Wide QRS complexes only
D. Regular rhythm with upright P waves
Answer: B
Explanation: Atrial fibrillation produces chaotic atrial activity, resulting
in absent P waves and an irregularly irregular ventricular rhythm.
5. A client suddenly develops a rapid, regular rhythm at 180
beats/min with narrow QRS complexes. Which dysrhythmia is most
likely?
A. Ventricular fibrillation