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Relias Dysrhythmia Basic A Test Actual Exam
2025/2026 – Complete Exam-Style Questions with
Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
[SECTION 1: Cardiac Conduction System & ECG Basics — Questions 1-12]
Q1: The nurse is calculating the heart rate using the 6-second strip method. On a 30-large-box
strip (representing 6 seconds), 8 QRS complexes are counted. What is the heart rate?
A. 60 bpm
B. 75 bpm
C. 80 bpm
D. 96 bpm
Correct Answer: C
Rationale: To calculate heart rate using the 6-second strip method, count the number of QRS
complexes within 30 large boxes (6 seconds) and multiply by 10. In this scenario, 8 complexes
multiplied by 10 equals 80 bpm. Option A (60 bpm) would result from 6 complexes, Option B
(75 bpm) from 7.5 complexes (impossible count), and Option D (96 bpm) from 9.6 complexes.
This method is a standard rapid estimation technique in cardiac monitoring.
Q2: Which ECG lead placement is located at the 5th intercostal space, midclavicular line?
A. V1
B. V2
C. V3
D. V4
Correct Answer: D
Rationale: V4 is correctly placed at the 5th intercostal space in the midclavicular line. V1 is
placed at the 4th intercostal space right sternal border, and V2 is at the 4th intercostal space left
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sternal border. V3 is placed midway between V2 and V4. Proper anatomical landmarking is
essential for accurate ECG interpretation and detecting ischemic changes.
Q3: On an ECG tracing, the PR interval measures 0.24 seconds. How should the nurse interpret
this finding?
A. Normal interval
B. Prolonged interval
C. Shortened interval
D. Non-measurable interval
Correct Answer: B
Rationale: The normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small boxes). A PR
interval of 0.24 seconds indicates a delay in conduction from the SA node through the AV node,
classified as a prolonged PR interval or First-degree AV block. Option A is incorrect because it
exceeds the upper limit of normal. Option C would indicate pre-excitation (e.g., Wolff-
Parkinson-White), and Option D implies an absence of atrial conduction, such as in atrial
fibrillation.
Q4: Which component of the ECG represents ventricular repolarization?
A. P wave
B. QRS complex
C. ST segment
D. T wave
Correct Answer: D
Rationale: The T wave represents ventricular repolarization, or the recovery of the ventricular
muscle cells. The P wave represents atrial depolarization, and the QRS complex represents
ventricular depolarization. The ST segment represents the early phase of ventricular
repolarization and is normally isoelectric; elevation or depression here indicates ischemia or
injury.
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Q5: A patient has an intrinsic heart rate of 45 bpm. The ECG shows a narrow QRS complex with
a regular rhythm, but no visible P waves. Which pacemaker is most likely acting as the escape
rhythm?
A. SA Node
B. AV Node (Junctional)
C. Purkinje Fibers
D. Atrial Foci
Correct Answer: B
Rationale: The inherent rate of the AV junction is 40 to 60 bpm. The rhythm described (regular,
narrow QRS, rate 45) aligns with a junctional escape rhythm. The SA node fires at 60-100 bpm
(A is incorrect), and Purkinje fibers fire at 20-40 bpm (C is incorrect). Atrial foci typically would
show P waves with abnormal morphology (D is incorrect). Junctional rhythms dominate when
the SA node fails.
Q6: What is the correct interpretation of a QT interval measurement of 0.52 seconds in a male
patient?
A. Normal
B. Prolonged
C. Shortened
D. Non-diagnostic
Correct Answer: B
Rationale: The normal corrected QT interval (QTc) is generally less than 0.44 seconds (440 ms)
in males and less than 0.46 seconds in females. A QT interval of 0.52 seconds is significantly
prolonged, which increases the risk of torsades de pointes. Options A and C are incorrect based
on standard values. Option D is incorrect because a prolonged QT is a critical diagnostic finding
requiring medication review.
Q7: Which cardiac property refers to the ability of the cardiac cells to generate an electrical
impulse spontaneously?
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A. Conductivity
B. Contractility
C. Automaticity
D. Excitability
Correct Answer: C
Rationale: Automaticity is the property of specialized cardiac cells to spontaneously depolarize
and generate an electrical impulse without external stimulation. Conductivity is the transmission
of impulses, contractility is the mechanical pumping ability, and excitability is the ability to
respond to an electrical stimulus. Understanding automaticity explains why ectopic beats or
escape rhythms occur.
Q8: The nurse observes that the QRS complex duration is 0.14 seconds. What does this indicate?
A. Normal ventricular depolarization
B. Abnormal conduction within the ventricles
C. Fast atrial rate
D. Normal atrial repolarization
Correct Answer: B
Rationale: The normal QRS duration is 0.06 to 0.10 seconds (up to 0.12 seconds in some
criteria). A QRS of 0.14 seconds is wide, indicating abnormal conduction through the ventricles,
such as a bundle branch block, ventricular rhythm, or aberrancy. Option A is incorrect because a
narrow QRS represents normal conduction. Options C and D relate to atrial activity and
repolarization, not ventricular depolarization time.
Q9: How many millimeters does one large box represent on standard ECG paper (vertical axis) at
standard calibration?
A. 5 mm
B. 10 mm
C. 15 mm
Relias Dysrhythmia Basic A Test Actual Exam
2025/2026 – Complete Exam-Style Questions with
Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
[SECTION 1: Cardiac Conduction System & ECG Basics — Questions 1-12]
Q1: The nurse is calculating the heart rate using the 6-second strip method. On a 30-large-box
strip (representing 6 seconds), 8 QRS complexes are counted. What is the heart rate?
A. 60 bpm
B. 75 bpm
C. 80 bpm
D. 96 bpm
Correct Answer: C
Rationale: To calculate heart rate using the 6-second strip method, count the number of QRS
complexes within 30 large boxes (6 seconds) and multiply by 10. In this scenario, 8 complexes
multiplied by 10 equals 80 bpm. Option A (60 bpm) would result from 6 complexes, Option B
(75 bpm) from 7.5 complexes (impossible count), and Option D (96 bpm) from 9.6 complexes.
This method is a standard rapid estimation technique in cardiac monitoring.
Q2: Which ECG lead placement is located at the 5th intercostal space, midclavicular line?
A. V1
B. V2
C. V3
D. V4
Correct Answer: D
Rationale: V4 is correctly placed at the 5th intercostal space in the midclavicular line. V1 is
placed at the 4th intercostal space right sternal border, and V2 is at the 4th intercostal space left
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sternal border. V3 is placed midway between V2 and V4. Proper anatomical landmarking is
essential for accurate ECG interpretation and detecting ischemic changes.
Q3: On an ECG tracing, the PR interval measures 0.24 seconds. How should the nurse interpret
this finding?
A. Normal interval
B. Prolonged interval
C. Shortened interval
D. Non-measurable interval
Correct Answer: B
Rationale: The normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small boxes). A PR
interval of 0.24 seconds indicates a delay in conduction from the SA node through the AV node,
classified as a prolonged PR interval or First-degree AV block. Option A is incorrect because it
exceeds the upper limit of normal. Option C would indicate pre-excitation (e.g., Wolff-
Parkinson-White), and Option D implies an absence of atrial conduction, such as in atrial
fibrillation.
Q4: Which component of the ECG represents ventricular repolarization?
A. P wave
B. QRS complex
C. ST segment
D. T wave
Correct Answer: D
Rationale: The T wave represents ventricular repolarization, or the recovery of the ventricular
muscle cells. The P wave represents atrial depolarization, and the QRS complex represents
ventricular depolarization. The ST segment represents the early phase of ventricular
repolarization and is normally isoelectric; elevation or depression here indicates ischemia or
injury.
,3
Q5: A patient has an intrinsic heart rate of 45 bpm. The ECG shows a narrow QRS complex with
a regular rhythm, but no visible P waves. Which pacemaker is most likely acting as the escape
rhythm?
A. SA Node
B. AV Node (Junctional)
C. Purkinje Fibers
D. Atrial Foci
Correct Answer: B
Rationale: The inherent rate of the AV junction is 40 to 60 bpm. The rhythm described (regular,
narrow QRS, rate 45) aligns with a junctional escape rhythm. The SA node fires at 60-100 bpm
(A is incorrect), and Purkinje fibers fire at 20-40 bpm (C is incorrect). Atrial foci typically would
show P waves with abnormal morphology (D is incorrect). Junctional rhythms dominate when
the SA node fails.
Q6: What is the correct interpretation of a QT interval measurement of 0.52 seconds in a male
patient?
A. Normal
B. Prolonged
C. Shortened
D. Non-diagnostic
Correct Answer: B
Rationale: The normal corrected QT interval (QTc) is generally less than 0.44 seconds (440 ms)
in males and less than 0.46 seconds in females. A QT interval of 0.52 seconds is significantly
prolonged, which increases the risk of torsades de pointes. Options A and C are incorrect based
on standard values. Option D is incorrect because a prolonged QT is a critical diagnostic finding
requiring medication review.
Q7: Which cardiac property refers to the ability of the cardiac cells to generate an electrical
impulse spontaneously?
, 4
A. Conductivity
B. Contractility
C. Automaticity
D. Excitability
Correct Answer: C
Rationale: Automaticity is the property of specialized cardiac cells to spontaneously depolarize
and generate an electrical impulse without external stimulation. Conductivity is the transmission
of impulses, contractility is the mechanical pumping ability, and excitability is the ability to
respond to an electrical stimulus. Understanding automaticity explains why ectopic beats or
escape rhythms occur.
Q8: The nurse observes that the QRS complex duration is 0.14 seconds. What does this indicate?
A. Normal ventricular depolarization
B. Abnormal conduction within the ventricles
C. Fast atrial rate
D. Normal atrial repolarization
Correct Answer: B
Rationale: The normal QRS duration is 0.06 to 0.10 seconds (up to 0.12 seconds in some
criteria). A QRS of 0.14 seconds is wide, indicating abnormal conduction through the ventricles,
such as a bundle branch block, ventricular rhythm, or aberrancy. Option A is incorrect because a
narrow QRS represents normal conduction. Options C and D relate to atrial activity and
repolarization, not ventricular depolarization time.
Q9: How many millimeters does one large box represent on standard ECG paper (vertical axis) at
standard calibration?
A. 5 mm
B. 10 mm
C. 15 mm
