Relias Dysrhythmia Basic A Assessment
2026 Practice Questions & Answers PDF |
ECG & Cardiac Rhythm Interpretation Study
Guide with Verified Solutions & Rationales
• This 200-question practice guide mirrors the Relias Dysrhythmia Basic A
Assessment 2026, covering ECG interpretation, cardiac rhythm identification, and
clinical management with verified answers and detailed EXPERT RATIONALE.
• Use this material by reading each question carefully, selecting your answer
mentally before checking the bolded correct answer and EXPERT RATIONALE
below each question to reinforce understanding and fill knowledge gaps.
1. What is the normal resting heart rate for an adult?
A. 40–60 beats per minute
B. 50–90 beats per minute
C. 60–100 beats per minute
D. 80–120 beats per minute
E. 100–150 beats per minute
Correct Answer: C. 60–100 beats per minute
EXPERT RATIONALE: The normal adult resting heart rate is defined as 60–100
beats per minute. Rates below 60 bpm are classified as bradycardia, while rates
above 100 bpm are classified as tachycardia. This range reflects normal
automaticity of the sinoatrial (SA) node.
2. Which structure is known as the primary pacemaker of the heart?
A. Atrioventricular (AV) node
B. Bundle of His
C. Purkinje fibers
D. Sinoatrial (SA) node
,E. Bundle branches
Correct Answer: D. Sinoatrial (SA) node
EXPERT RATIONALE: The SA node, located in the right atrium, is the heart's primary
pacemaker. It spontaneously generates electrical impulses at a rate of 60–100 bpm
and initiates each normal cardiac cycle. All other conduction structures are
secondary pacemakers with slower intrinsic rates.
3. On an ECG, what does the P wave represent?
A. Ventricular depolarization
B. Atrial repolarization
C. Ventricular repolarization
D. Atrial depolarization
E. Bundle branch conduction
Correct Answer: D. Atrial depolarization
EXPERT RATIONALE: The P wave represents the electrical depolarization of the
atria, which triggers atrial contraction. It precedes the QRS complex and should be
upright in leads II, III, and aVF in normal sinus rhythm.
4. What does the QRS complex represent on an ECG?
A. Atrial depolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. SA node firing
E. Atrial repolarization
Correct Answer: C. Ventricular depolarization
,EXPERT RATIONALE: The QRS complex represents ventricular depolarization — the
electrical activation of the ventricles that triggers ventricular contraction (systole).
The normal QRS duration is 0.06–0.12 seconds (1.5–3 small squares on ECG paper).
5. What does the T wave represent on an ECG?
A. Atrial depolarization
B. Ventricular depolarization
C. SA node repolarization
D. Atrial repolarization
E. Ventricular repolarization
Correct Answer: E. Ventricular repolarization
EXPERT RATIONALE: The T wave reflects ventricular repolarization — the recovery
phase of the ventricles after contraction. It follows the QRS complex and is normally
upright in most leads. Inverted T waves can indicate ischemia or other pathology.
6. What is the normal PR interval duration?
A. 0.04–0.08 seconds
B. 0.06–0.10 seconds
C. 0.12–0.20 seconds
D. 0.20–0.28 seconds
E. 0.28–0.36 seconds
Correct Answer: C. 0.12–0.20 seconds
EXPERT RATIONALE: The PR interval represents the time from the beginning of
atrial depolarization to the beginning of ventricular depolarization, which includes
conduction through the AV node. Normal duration is 0.12–0.20 seconds (3–5 small
squares). A prolonged PR interval may indicate first-degree AV block.
, 7. What is the normal QRS complex duration?
A. 0.04–0.08 seconds
B. 0.06–0.12 seconds
C. 0.12–0.20 seconds
D. 0.20–0.24 seconds
E. 0.24–0.30 seconds
Correct Answer: B. 0.06–0.12 seconds
EXPERT RATIONALE: The normal QRS duration is 0.06–0.12 seconds. A QRS wider
than 0.12 seconds suggests abnormal ventricular conduction such as a bundle
branch block, ventricular rhythm, or aberrant conduction.
8. In a standard ECG, each small square on the horizontal axis represents how
much time?
A. 0.02 seconds
B. 0.04 seconds
C. 0.04 seconds
D. 0.20 seconds
E. 0.04 seconds
Correct Answer: B. 0.04 seconds
EXPERT RATIONALE: On standard ECG paper run at 25 mm/second, each small
square on the horizontal axis represents 0.04 seconds (40 milliseconds). Each large
square (5 small squares) represents 0.20 seconds. This standardization allows
accurate measurement of intervals and durations.
2026 Practice Questions & Answers PDF |
ECG & Cardiac Rhythm Interpretation Study
Guide with Verified Solutions & Rationales
• This 200-question practice guide mirrors the Relias Dysrhythmia Basic A
Assessment 2026, covering ECG interpretation, cardiac rhythm identification, and
clinical management with verified answers and detailed EXPERT RATIONALE.
• Use this material by reading each question carefully, selecting your answer
mentally before checking the bolded correct answer and EXPERT RATIONALE
below each question to reinforce understanding and fill knowledge gaps.
1. What is the normal resting heart rate for an adult?
A. 40–60 beats per minute
B. 50–90 beats per minute
C. 60–100 beats per minute
D. 80–120 beats per minute
E. 100–150 beats per minute
Correct Answer: C. 60–100 beats per minute
EXPERT RATIONALE: The normal adult resting heart rate is defined as 60–100
beats per minute. Rates below 60 bpm are classified as bradycardia, while rates
above 100 bpm are classified as tachycardia. This range reflects normal
automaticity of the sinoatrial (SA) node.
2. Which structure is known as the primary pacemaker of the heart?
A. Atrioventricular (AV) node
B. Bundle of His
C. Purkinje fibers
D. Sinoatrial (SA) node
,E. Bundle branches
Correct Answer: D. Sinoatrial (SA) node
EXPERT RATIONALE: The SA node, located in the right atrium, is the heart's primary
pacemaker. It spontaneously generates electrical impulses at a rate of 60–100 bpm
and initiates each normal cardiac cycle. All other conduction structures are
secondary pacemakers with slower intrinsic rates.
3. On an ECG, what does the P wave represent?
A. Ventricular depolarization
B. Atrial repolarization
C. Ventricular repolarization
D. Atrial depolarization
E. Bundle branch conduction
Correct Answer: D. Atrial depolarization
EXPERT RATIONALE: The P wave represents the electrical depolarization of the
atria, which triggers atrial contraction. It precedes the QRS complex and should be
upright in leads II, III, and aVF in normal sinus rhythm.
4. What does the QRS complex represent on an ECG?
A. Atrial depolarization
B. Ventricular repolarization
C. Ventricular depolarization
D. SA node firing
E. Atrial repolarization
Correct Answer: C. Ventricular depolarization
,EXPERT RATIONALE: The QRS complex represents ventricular depolarization — the
electrical activation of the ventricles that triggers ventricular contraction (systole).
The normal QRS duration is 0.06–0.12 seconds (1.5–3 small squares on ECG paper).
5. What does the T wave represent on an ECG?
A. Atrial depolarization
B. Ventricular depolarization
C. SA node repolarization
D. Atrial repolarization
E. Ventricular repolarization
Correct Answer: E. Ventricular repolarization
EXPERT RATIONALE: The T wave reflects ventricular repolarization — the recovery
phase of the ventricles after contraction. It follows the QRS complex and is normally
upright in most leads. Inverted T waves can indicate ischemia or other pathology.
6. What is the normal PR interval duration?
A. 0.04–0.08 seconds
B. 0.06–0.10 seconds
C. 0.12–0.20 seconds
D. 0.20–0.28 seconds
E. 0.28–0.36 seconds
Correct Answer: C. 0.12–0.20 seconds
EXPERT RATIONALE: The PR interval represents the time from the beginning of
atrial depolarization to the beginning of ventricular depolarization, which includes
conduction through the AV node. Normal duration is 0.12–0.20 seconds (3–5 small
squares). A prolonged PR interval may indicate first-degree AV block.
, 7. What is the normal QRS complex duration?
A. 0.04–0.08 seconds
B. 0.06–0.12 seconds
C. 0.12–0.20 seconds
D. 0.20–0.24 seconds
E. 0.24–0.30 seconds
Correct Answer: B. 0.06–0.12 seconds
EXPERT RATIONALE: The normal QRS duration is 0.06–0.12 seconds. A QRS wider
than 0.12 seconds suggests abnormal ventricular conduction such as a bundle
branch block, ventricular rhythm, or aberrant conduction.
8. In a standard ECG, each small square on the horizontal axis represents how
much time?
A. 0.02 seconds
B. 0.04 seconds
C. 0.04 seconds
D. 0.20 seconds
E. 0.04 seconds
Correct Answer: B. 0.04 seconds
EXPERT RATIONALE: On standard ECG paper run at 25 mm/second, each small
square on the horizontal axis represents 0.04 seconds (40 milliseconds). Each large
square (5 small squares) represents 0.20 seconds. This standardization allows
accurate measurement of intervals and durations.
