ECG Interpretation for Nurses & Cardiac Arrhythmia Recognition
Practice Exam 2026 | Comprehensive ECG/EKG Interpretation Study
Guide | Heart Rhythm Analysis, Arrhythmia Identification,
Dysrhythmias, Cardiac Monitoring & Nursing Interventions |
University/College Nursing Program – 190 Multiple-Choice Questions
with Answers
Question 1
Which waveform on the ECG represents ventricular depolarization?
A. P wave
B. PR interval
C. QRS complex
D. T wave
Correct Answer: C
Explanation: The QRS complex reflects depolarization of the ventricles; its duration and
morphology reveal conduction integrity. The P wave is atrial depolarization, and the T
wave is ventricular repolarization.
Question 2
The normal duration of the PR interval in adults is:
,A. 0.04–0.10 seconds
B. 0.12–0.20 seconds
C. 0.20–0.28 seconds
D. 0.28–0.36 seconds
Correct Answer: B
Explanation: A normal PR interval measures 0.12–0.20 seconds (3–5 small boxes);
prolongation beyond 0.20 seconds suggests first-degree AV block.
Question 3
On standard ECG paper, one small box represents how much time?
A. 0.02 seconds
B. 0.04 seconds
C. 0.10 seconds
D. 0.20 seconds
Correct Answer: B
Explanation: Each small box equals 0.04 seconds at 25 mm/sec; five small boxes (one
large box) equal 0.20 seconds.
Question 4
A nurse notes a QRS duration of 0.14 seconds. This finding indicates:
A. Normal ventricular conduction
B. Supraventricular origin
,C. Widened QRS, suggesting ventricular or aberrant conduction
D. Atrial fibrillation
Correct Answer: C
Explanation: QRS >0.12 seconds indicates delayed ventricular conduction, seen in
bundle branch blocks, ventricular rhythms, or aberrant conduction.
Question 5
Which lead is most useful for continuous bedside monitoring of arrhythmias?
A. Lead II
B. Lead aVR
C. Lead V1
D. Lead V6
Correct Answer: A
Explanation: Lead II is parallel to the heart's electrical axis, producing prominent P
waves and clear QRS complexes ideal for rhythm monitoring.
Question 6
The isoelectric line on an ECG represents:
A. Ventricular repolarization
B. Electrical baseline with no net current flow
C. Atrial contraction
D. Peak of the R wave
, Correct Answer: B
Explanation: The isoelectric line is the baseline between waves where no net electrical
activity is recorded; deviations indicate ST-segment changes.
Question 7
Which interval reflects the time from the onset of atrial depolarization to the onset of
ventricular depolarization?
A. QT interval
B. RR interval
C. PR interval
D. ST segment
Correct Answer: C
Explanation: The PR interval measures from the start of the P wave to the start of the
QRS, encompassing atrial depolarization and AV nodal delay.
Question 8
A normal QT interval in adults at heart rates of 60–100 bpm is generally:
A. 0.20–0.30 seconds
B. 0.30–0.44 seconds
C. 0.44–0.60 seconds
D. 0.10–0.20 seconds
Correct Answer: B
Practice Exam 2026 | Comprehensive ECG/EKG Interpretation Study
Guide | Heart Rhythm Analysis, Arrhythmia Identification,
Dysrhythmias, Cardiac Monitoring & Nursing Interventions |
University/College Nursing Program – 190 Multiple-Choice Questions
with Answers
Question 1
Which waveform on the ECG represents ventricular depolarization?
A. P wave
B. PR interval
C. QRS complex
D. T wave
Correct Answer: C
Explanation: The QRS complex reflects depolarization of the ventricles; its duration and
morphology reveal conduction integrity. The P wave is atrial depolarization, and the T
wave is ventricular repolarization.
Question 2
The normal duration of the PR interval in adults is:
,A. 0.04–0.10 seconds
B. 0.12–0.20 seconds
C. 0.20–0.28 seconds
D. 0.28–0.36 seconds
Correct Answer: B
Explanation: A normal PR interval measures 0.12–0.20 seconds (3–5 small boxes);
prolongation beyond 0.20 seconds suggests first-degree AV block.
Question 3
On standard ECG paper, one small box represents how much time?
A. 0.02 seconds
B. 0.04 seconds
C. 0.10 seconds
D. 0.20 seconds
Correct Answer: B
Explanation: Each small box equals 0.04 seconds at 25 mm/sec; five small boxes (one
large box) equal 0.20 seconds.
Question 4
A nurse notes a QRS duration of 0.14 seconds. This finding indicates:
A. Normal ventricular conduction
B. Supraventricular origin
,C. Widened QRS, suggesting ventricular or aberrant conduction
D. Atrial fibrillation
Correct Answer: C
Explanation: QRS >0.12 seconds indicates delayed ventricular conduction, seen in
bundle branch blocks, ventricular rhythms, or aberrant conduction.
Question 5
Which lead is most useful for continuous bedside monitoring of arrhythmias?
A. Lead II
B. Lead aVR
C. Lead V1
D. Lead V6
Correct Answer: A
Explanation: Lead II is parallel to the heart's electrical axis, producing prominent P
waves and clear QRS complexes ideal for rhythm monitoring.
Question 6
The isoelectric line on an ECG represents:
A. Ventricular repolarization
B. Electrical baseline with no net current flow
C. Atrial contraction
D. Peak of the R wave
, Correct Answer: B
Explanation: The isoelectric line is the baseline between waves where no net electrical
activity is recorded; deviations indicate ST-segment changes.
Question 7
Which interval reflects the time from the onset of atrial depolarization to the onset of
ventricular depolarization?
A. QT interval
B. RR interval
C. PR interval
D. ST segment
Correct Answer: C
Explanation: The PR interval measures from the start of the P wave to the start of the
QRS, encompassing atrial depolarization and AV nodal delay.
Question 8
A normal QT interval in adults at heart rates of 60–100 bpm is generally:
A. 0.20–0.30 seconds
B. 0.30–0.44 seconds
C. 0.44–0.60 seconds
D. 0.10–0.20 seconds
Correct Answer: B
