Relias Dysrhythmia Basic B Clinical Assessment 2026 Questions & Answers with
Rationales
Core Concepts & Fundamentals (Questions 1-20)
Question 1: Which part of the cardiac conduction system acts as the primary
pacemaker of the heart?
A. AV Node
B. SA Node
C. Bundle of His
D. Purkinje Fibers
Correct Answer: B. SA Node
Rationale: The Sinoatrial (SA) node is the intrinsic pacemaker of the heart,
typically initiating impulses at a rate of 60 to 100 beats per minute. It is located in
,the right atrium and generates electrical impulses that spread throughout the
heart.
Question 2: What is the normal intrinsic firing rate of the SA node?
A. 20-40 bpm
B. 40-60 bpm
C. 60-100 bpm
D. 100-150 bpm
Correct Answer: C. 60-100 bpm
Rationale: The SA node normally fires at 60-100 beats per minute. If the SA node
fails, the AV node can take over as a secondary pacemaker at 40-60 bpm, and the
Purkinje fibers as a tertiary pacemaker at 20-40 bpm.
Question 3: The intrinsic firing rate of the AV (Junctional) tissue is:
,A. 60-100 bpm
B. 40-60 bpm
C. 20-40 bpm
D. 100-150 bpm
Correct Answer: B. 40-60 bpm
Rationale: If the SA node fails, the AV junction takes over at its inherent rate of 40
to 60 beats per minute. This is called a junctional escape rhythm.
Question 4: A PR interval is measured from the:
A. Beginning of the P wave to the beginning of the QRS complex
B. Peak of the P wave to the R wave
, C. End of the P wave to the start of the QRS
D. Beginning of the P wave to the end of the P wave
Correct Answer: A. Beginning of the P wave to the beginning of the QRS complex
Rationale: The PR interval represents the time from atrial depolarization to the
start of ventricular depolarization (AV conduction time). The normal PR interval is
0.12 to 0.20 seconds.
Question 5: The QRS complex represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Atrial repolarization
D. Ventricular repolarization
Rationales
Core Concepts & Fundamentals (Questions 1-20)
Question 1: Which part of the cardiac conduction system acts as the primary
pacemaker of the heart?
A. AV Node
B. SA Node
C. Bundle of His
D. Purkinje Fibers
Correct Answer: B. SA Node
Rationale: The Sinoatrial (SA) node is the intrinsic pacemaker of the heart,
typically initiating impulses at a rate of 60 to 100 beats per minute. It is located in
,the right atrium and generates electrical impulses that spread throughout the
heart.
Question 2: What is the normal intrinsic firing rate of the SA node?
A. 20-40 bpm
B. 40-60 bpm
C. 60-100 bpm
D. 100-150 bpm
Correct Answer: C. 60-100 bpm
Rationale: The SA node normally fires at 60-100 beats per minute. If the SA node
fails, the AV node can take over as a secondary pacemaker at 40-60 bpm, and the
Purkinje fibers as a tertiary pacemaker at 20-40 bpm.
Question 3: The intrinsic firing rate of the AV (Junctional) tissue is:
,A. 60-100 bpm
B. 40-60 bpm
C. 20-40 bpm
D. 100-150 bpm
Correct Answer: B. 40-60 bpm
Rationale: If the SA node fails, the AV junction takes over at its inherent rate of 40
to 60 beats per minute. This is called a junctional escape rhythm.
Question 4: A PR interval is measured from the:
A. Beginning of the P wave to the beginning of the QRS complex
B. Peak of the P wave to the R wave
, C. End of the P wave to the start of the QRS
D. Beginning of the P wave to the end of the P wave
Correct Answer: A. Beginning of the P wave to the beginning of the QRS complex
Rationale: The PR interval represents the time from atrial depolarization to the
start of ventricular depolarization (AV conduction time). The normal PR interval is
0.12 to 0.20 seconds.
Question 5: The QRS complex represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Atrial repolarization
D. Ventricular repolarization
