NUR-255 Test 1 Exam Review | Complete Study
Guide with Complete Actual Exam Questions and
Verified Correct Detailed Answers| Latest Test -
Updated 2026/2027
Midlands Technical College
Question 1
When computing a heart rate on a patient's electrocardiogram (ECG) tracing, the nurse
counts 15 small blocks in an R-R interval. The rhythm is regular. Which heart rate in
beats/min would the nurse document?
A. 60
B. 75
C. 100
D. 150
Answer: C
Rationale: Each small block on ECG paper represents 0.04 second. 1500 small blocks
= 1 minute. Heart rate = 1500 ÷ number of small blocks between R waves. 1500 ÷ 15 =
100 beats/min.
Question 2
Which phrase describes the electrical activity represented by the PR interval on an
electrocardiogram (ECG)?
A. The length of time it takes to depolarize the atrium
B. The length of time it takes for the atria to depolarize and repolarize
C. The length of time for the electrical impulse to travel from the sinoatrial (SA) node to
the Purkinje fibers
D. The length of time it takes for the electrical impulse to travel from the SA node to the
atrioventricular (AV) node
Answer: C
Rationale: The PR interval measures the time from the beginning of the P wave to the
beginning of the QRS complex, representing the time for the electrical impulse to travel
from the SA node through the AV node to the Purkinje fibers.
pg. 1
,Question 3
Which electrocardiogram (ECG) characteristic will be present if a patient is experiencing
unifocal premature ventricular contractions (PVCs)? Select all that apply.
1. Normal T wave
2. Normal P wave
3. PR interval that is not measurable
4. Wide and distorted QRS complex
5. PVCs that have the same shape
A. 1,3,4,5
B. 2,3,4,5
C. 3,4,5
D. 1,2,3
E. All
F. None
Answer: A
Rationale: PVCs have a normal T wave (1), non-measurable PR interval (3),
wide/distorted QRS complex (4), and same shape if unifocal (5). P waves are rarely
visible and hidden in the PVC (2).
Question 4
A patient's electrocardiogram (ECG) shows a heart rate of 150 beats/min and a normal P
wave preceding each QRS complex. Which interpretation would the nurse make of these
findings?
A. Atrial fibrillation
B. Sinus tachycardia
C. Ventricular fibrillation
D. Premature atrial contractions
Answer: B
Rationale: Sinus tachycardia has a heart rate of 101-180 beats/min with a normal P
wave preceding each QRS complex.
Question 5
A patient's electrocardiogram (ECG) shows prolonged PR interval, normal P waves, and
pg. 2
, normal QRS complexes. The patient is asymptomatic and has a normal heart rate and a
regular rhythm. Which type of atrioventricular (AV) block is present?
A. First-degree AV block
B. Third-degree AV block
C. Type I second-degree AV block
D. Type II second-degree AV block
Answer: A
Rationale: First-degree AV block shows prolonged PR interval with normal P waves
and QRS complexes. The patient is asymptomatic with normal rate and regular rhythm.
Question 6
A patient's electrocardiogram (ECG) tracing shows occasional wide and distorted QRS
complexes. Which rhythm does this finding indicate?
A. Sinus tachycardia
B. Ventricular fibrillation
C. Junctional dysrhythmias
D. Premature ventricular contractions
Answer: D
Rationale: Premature ventricular contractions originate from the ventricles, causing
wide and distorted QRS complexes.
Question 7
Which time period does the T wave in an electrocardiogram (ECG) represent?
A. Ventricular repolarization
B. Depolarization of both ventricles
C. Passage of the electrical impulse through the atrium
D. Time between ventricular depolarization and repolarization
Answer: A
Rationale: The T wave represents ventricular repolarization. The QRS complex
represents ventricular depolarization.
Question 8
In which order do electrical impulses travel through the heart?
1. Bundle of His
pg. 3
Guide with Complete Actual Exam Questions and
Verified Correct Detailed Answers| Latest Test -
Updated 2026/2027
Midlands Technical College
Question 1
When computing a heart rate on a patient's electrocardiogram (ECG) tracing, the nurse
counts 15 small blocks in an R-R interval. The rhythm is regular. Which heart rate in
beats/min would the nurse document?
A. 60
B. 75
C. 100
D. 150
Answer: C
Rationale: Each small block on ECG paper represents 0.04 second. 1500 small blocks
= 1 minute. Heart rate = 1500 ÷ number of small blocks between R waves. 1500 ÷ 15 =
100 beats/min.
Question 2
Which phrase describes the electrical activity represented by the PR interval on an
electrocardiogram (ECG)?
A. The length of time it takes to depolarize the atrium
B. The length of time it takes for the atria to depolarize and repolarize
C. The length of time for the electrical impulse to travel from the sinoatrial (SA) node to
the Purkinje fibers
D. The length of time it takes for the electrical impulse to travel from the SA node to the
atrioventricular (AV) node
Answer: C
Rationale: The PR interval measures the time from the beginning of the P wave to the
beginning of the QRS complex, representing the time for the electrical impulse to travel
from the SA node through the AV node to the Purkinje fibers.
pg. 1
,Question 3
Which electrocardiogram (ECG) characteristic will be present if a patient is experiencing
unifocal premature ventricular contractions (PVCs)? Select all that apply.
1. Normal T wave
2. Normal P wave
3. PR interval that is not measurable
4. Wide and distorted QRS complex
5. PVCs that have the same shape
A. 1,3,4,5
B. 2,3,4,5
C. 3,4,5
D. 1,2,3
E. All
F. None
Answer: A
Rationale: PVCs have a normal T wave (1), non-measurable PR interval (3),
wide/distorted QRS complex (4), and same shape if unifocal (5). P waves are rarely
visible and hidden in the PVC (2).
Question 4
A patient's electrocardiogram (ECG) shows a heart rate of 150 beats/min and a normal P
wave preceding each QRS complex. Which interpretation would the nurse make of these
findings?
A. Atrial fibrillation
B. Sinus tachycardia
C. Ventricular fibrillation
D. Premature atrial contractions
Answer: B
Rationale: Sinus tachycardia has a heart rate of 101-180 beats/min with a normal P
wave preceding each QRS complex.
Question 5
A patient's electrocardiogram (ECG) shows prolonged PR interval, normal P waves, and
pg. 2
, normal QRS complexes. The patient is asymptomatic and has a normal heart rate and a
regular rhythm. Which type of atrioventricular (AV) block is present?
A. First-degree AV block
B. Third-degree AV block
C. Type I second-degree AV block
D. Type II second-degree AV block
Answer: A
Rationale: First-degree AV block shows prolonged PR interval with normal P waves
and QRS complexes. The patient is asymptomatic with normal rate and regular rhythm.
Question 6
A patient's electrocardiogram (ECG) tracing shows occasional wide and distorted QRS
complexes. Which rhythm does this finding indicate?
A. Sinus tachycardia
B. Ventricular fibrillation
C. Junctional dysrhythmias
D. Premature ventricular contractions
Answer: D
Rationale: Premature ventricular contractions originate from the ventricles, causing
wide and distorted QRS complexes.
Question 7
Which time period does the T wave in an electrocardiogram (ECG) represent?
A. Ventricular repolarization
B. Depolarization of both ventricles
C. Passage of the electrical impulse through the atrium
D. Time between ventricular depolarization and repolarization
Answer: A
Rationale: The T wave represents ventricular repolarization. The QRS complex
represents ventricular depolarization.
Question 8
In which order do electrical impulses travel through the heart?
1. Bundle of His
pg. 3
