Relias Dysrhythmia Basic B Actual Exam – Relias Learning Systems –
2026/2027 Academic Year – Verified Questions and Answers for
Healthcare Professionals and Nursing Staff
Question 1
The electrical impulse normally originates from which structure of the heart?
A) AV node
B) Bundle of His
C) SA node
D) Purkinje fibers
Answer: C) SA node
Rationale: The sinoatrial (SA) node is the heart's primary pacemaker, located in the right
atrium. It normally initiates impulses at a rate of 60-100 bpm .
Question 2
What is the normal intrinsic firing rate of the AV node?
A) 20-40 bpm
B) 40-60 bpm
C) 60-100 bpm
D) 100-150 bpm
Answer: B) 40-60 bpm
Rationale: The AV node serves as the secondary pacemaker with an intrinsic rate of 40-
60 bpm. It takes over if the SA node fails .
Question 3
Which ECG component represents ventricular depolarization?
A) P wave
B) PR interval
,C) QRS complex
D) T wave
Answer: C) QRS complex
Rationale: The QRS complex reflects the electrical impulse as it travels through the
ventricles, causing ventricular contraction. A normal QRS is narrow (<0.12 seconds) .
Question 4
What is the normal duration of the PR interval?
A) 0.04-0.10 seconds
B) 0.06-0.12 seconds
C) 0.12-0.20 seconds
D) 0.20-0.35 seconds
Answer: C) 0.12-0.20 seconds
Rationale: The PR interval measures the time from the start of atrial depolarization to
the start of ventricular depolarization, including conduction through the AV node .
Question 5
The T wave on an ECG represents:
A) Atrial depolarization
B) Ventricular depolarization
C) Atrial repolarization
D) Ventricular repolarization
Answer: D) Ventricular repolarization
Rationale: The T wave represents the recovery or repolarization phase of the ventricles
after they have contracted .
Question 6
A patient's ECG shows a regular rhythm with a heart rate of 82 bpm. There is a P wave
before every QRS complex, the PR interval measures 0.18 seconds, and the QRS complex
measures 0.08 seconds. What is this rhythm?
,A) Sinus Bradycardia
B) Normal Sinus Rhythm
C) Sinus Tachycardia
D) First-Degree AV Block
Answer: B) Normal Sinus Rhythm
Rationale: Normal Sinus Rhythm (NSR) originates from the SA node with a rate of 60-
100 bpm, has a consistent P wave before each QRS, and normal PR (0.12-0.20s) and QRS
(<0.12s) intervals .
Question 7
Which of the following rhythms is characterized by a heart rate of less than 60 bpm and
all other characteristics of a normal sinus rhythm?
A) Sinus Tachycardia
B) Sinus Bradycardia
C) Sinus Arrhythmia
D) Junctional Rhythm
Answer: B) Sinus Bradycardia
Rationale: Sinus bradycardia is defined as a sinus rhythm with a rate below 60 bpm.
Conduction remains normal despite the slowed rate .
Question 8
A patient with a heart rate of 120 bpm, regular rhythm, and normal P waves is likely
experiencing which rhythm?
A) Sinus Bradycardia
B) Ventricular Tachycardia
C) Sinus Tachycardia
D) Atrial Flutter
Answer: C) Sinus Tachycardia
Rationale: Sinus tachycardia is a normal rhythm with an increased rate above 100 bpm
while maintaining a normal conduction pattern (P waves present, normal PR/QRS) .
, Question 9
A patient with symptomatic sinus bradycardia (hypotension, dizziness) should initially be
treated with:
A) Defibrillation
B) Atropine administration
C) Lidocaine infusion
D) Synchronized cardioversion
Answer: B) Atropine administration
Rationale: Atropine is the first-line medication for symptomatic bradycardia. It works by
inhibiting vagal stimulation on the SA node to increase the heart rate .
Question 10
Which of the following is NOT a characteristic of Sinus Arrhythmia?
A) Irregular rhythm
B) Rate increases with inspiration
C) Rate decreases with expiration
D) Rate is consistently >100 bpm
Answer: D) Rate is consistently >100 bpm
Rationale: Sinus arrhythmia is a normal variation where the heart rate varies with the
respiratory cycle (irregular rhythm). A rate consistently >100 bpm would be Sinus
Tachycardia .
Question 11
Which ECG finding is characteristic of Atrial Fibrillation?
A) Sawtooth flutter waves
B) Absent P waves with fibrillatory waves
C) Progressive PR prolongation
D) Wide QRS complexes
Answer: B) Absent P waves with fibrillatory waves
Rationale: In Atrial Fibrillation, the atria quiver instead of contracting in an organized
2026/2027 Academic Year – Verified Questions and Answers for
Healthcare Professionals and Nursing Staff
Question 1
The electrical impulse normally originates from which structure of the heart?
A) AV node
B) Bundle of His
C) SA node
D) Purkinje fibers
Answer: C) SA node
Rationale: The sinoatrial (SA) node is the heart's primary pacemaker, located in the right
atrium. It normally initiates impulses at a rate of 60-100 bpm .
Question 2
What is the normal intrinsic firing rate of the AV node?
A) 20-40 bpm
B) 40-60 bpm
C) 60-100 bpm
D) 100-150 bpm
Answer: B) 40-60 bpm
Rationale: The AV node serves as the secondary pacemaker with an intrinsic rate of 40-
60 bpm. It takes over if the SA node fails .
Question 3
Which ECG component represents ventricular depolarization?
A) P wave
B) PR interval
,C) QRS complex
D) T wave
Answer: C) QRS complex
Rationale: The QRS complex reflects the electrical impulse as it travels through the
ventricles, causing ventricular contraction. A normal QRS is narrow (<0.12 seconds) .
Question 4
What is the normal duration of the PR interval?
A) 0.04-0.10 seconds
B) 0.06-0.12 seconds
C) 0.12-0.20 seconds
D) 0.20-0.35 seconds
Answer: C) 0.12-0.20 seconds
Rationale: The PR interval measures the time from the start of atrial depolarization to
the start of ventricular depolarization, including conduction through the AV node .
Question 5
The T wave on an ECG represents:
A) Atrial depolarization
B) Ventricular depolarization
C) Atrial repolarization
D) Ventricular repolarization
Answer: D) Ventricular repolarization
Rationale: The T wave represents the recovery or repolarization phase of the ventricles
after they have contracted .
Question 6
A patient's ECG shows a regular rhythm with a heart rate of 82 bpm. There is a P wave
before every QRS complex, the PR interval measures 0.18 seconds, and the QRS complex
measures 0.08 seconds. What is this rhythm?
,A) Sinus Bradycardia
B) Normal Sinus Rhythm
C) Sinus Tachycardia
D) First-Degree AV Block
Answer: B) Normal Sinus Rhythm
Rationale: Normal Sinus Rhythm (NSR) originates from the SA node with a rate of 60-
100 bpm, has a consistent P wave before each QRS, and normal PR (0.12-0.20s) and QRS
(<0.12s) intervals .
Question 7
Which of the following rhythms is characterized by a heart rate of less than 60 bpm and
all other characteristics of a normal sinus rhythm?
A) Sinus Tachycardia
B) Sinus Bradycardia
C) Sinus Arrhythmia
D) Junctional Rhythm
Answer: B) Sinus Bradycardia
Rationale: Sinus bradycardia is defined as a sinus rhythm with a rate below 60 bpm.
Conduction remains normal despite the slowed rate .
Question 8
A patient with a heart rate of 120 bpm, regular rhythm, and normal P waves is likely
experiencing which rhythm?
A) Sinus Bradycardia
B) Ventricular Tachycardia
C) Sinus Tachycardia
D) Atrial Flutter
Answer: C) Sinus Tachycardia
Rationale: Sinus tachycardia is a normal rhythm with an increased rate above 100 bpm
while maintaining a normal conduction pattern (P waves present, normal PR/QRS) .
, Question 9
A patient with symptomatic sinus bradycardia (hypotension, dizziness) should initially be
treated with:
A) Defibrillation
B) Atropine administration
C) Lidocaine infusion
D) Synchronized cardioversion
Answer: B) Atropine administration
Rationale: Atropine is the first-line medication for symptomatic bradycardia. It works by
inhibiting vagal stimulation on the SA node to increase the heart rate .
Question 10
Which of the following is NOT a characteristic of Sinus Arrhythmia?
A) Irregular rhythm
B) Rate increases with inspiration
C) Rate decreases with expiration
D) Rate is consistently >100 bpm
Answer: D) Rate is consistently >100 bpm
Rationale: Sinus arrhythmia is a normal variation where the heart rate varies with the
respiratory cycle (irregular rhythm). A rate consistently >100 bpm would be Sinus
Tachycardia .
Question 11
Which ECG finding is characteristic of Atrial Fibrillation?
A) Sawtooth flutter waves
B) Absent P waves with fibrillatory waves
C) Progressive PR prolongation
D) Wide QRS complexes
Answer: B) Absent P waves with fibrillatory waves
Rationale: In Atrial Fibrillation, the atria quiver instead of contracting in an organized
