1|Page
RELIAS DYSRHYTHMIA BASIC A EXAM | STUDY
GUIDE | LATEST UPDATE 2026/2027 | PRACTICE
QUESTIONS AND ANSWERS | EXAM REVIEW
(BRAND NEW!!!).
Table of Contents
1. ECG Foundations, Measurements, and Heart Rate Calculation
2. Sinus Rhythms and Sinus Node Dysfunction
3. Atrial Dysrhythmias
4. Junctional Rhythms
5. Ventricular Dysrhythmias
6. AV Blocks and Conduction Disorders
7. Pacemaker Rhythms and Artifact Recognition
8. Clinical Interventions and ACLS Correlation
,2|Page
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
Correct Answer: C. SA node
The sinoatrial (SA) node, located in the right atrium, is the heart's natural pacemaker. It
normally discharges at 60-100 beats per minute. The AV node delays impulses; Purkinje
fibers are the terminal conduction pathway.
Question 2: At what rate does the SA node normally fire in a resting adult?
A. 20-40 beats per minute
B. 40-60 beats per minute
C. 60-100 beats per minute
D. 100-150 beats per minute
Correct Answer: C. 60-100 beats per minute
The SA node is the primary pacemaker with an intrinsic firing rate of 60-100 bpm. The AV
junction has a backup rate of 40-60 bpm, and the Purkinje fibers have an intrinsic rate of 20-
40 bpm.
Question 3: Which component of the ECG represents ventricular depolarization?
A. P wave
B. PR interval
C. QRS complex
D. T wave
Correct Answer: C. QRS complex
The QRS complex represents the electrical impulse traveling through the ventricles, causing
them to contract. The P wave represents atrial depolarization, and the T wave represents
ventricular repolarization.
Question 4: On standard ECG paper, what is the standard speed?
A. 15 mm/second
B. 25 mm/second
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C. 50 mm/second
D. 100 mm/second
Correct Answer: B. 25 mm/second
The standard ECG paper speed is 25 mm per second. At this speed, each small box (1 mm)
represents 0.04 seconds, and each large box (5 mm) represents 0.20 seconds.
Question 5: On standard ECG paper, 1 small box (1 mm) represents how many seconds?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.50 seconds
Correct Answer: A. 0.04 seconds
At standard speed (25 mm/sec), each small box = 0.04 sec (40 ms). Each large box (5 small
boxes) = 0.20 sec. The PR interval is normally 0.12–0.20 sec (3–5 small boxes).
Question 6: A normal PR interval should measure:
A. 0.04–0.08 seconds
B. 0.08–0.12 seconds
C. 0.12–0.20 seconds
D. 0.20–0.30 seconds
Correct Answer: C. 0.12–0.20 seconds
The normal PR interval ranges from 0.12 to 0.20 seconds (3-5 small boxes). It represents the
time from the onset of atrial depolarization to the onset of ventricular depolarization.
Question 7: What does the horizontal axis on an ECG measure?
A. Voltage
B. Time
C. Amplitude
D. Resistance
Correct Answer: B. Time
The horizontal axis on ECG paper measures time. The vertical axis measures voltage
(amplitude).
RELIAS DYSRHYTHMIA BASIC A EXAM | STUDY
GUIDE | LATEST UPDATE 2026/2027 | PRACTICE
QUESTIONS AND ANSWERS | EXAM REVIEW
(BRAND NEW!!!).
Table of Contents
1. ECG Foundations, Measurements, and Heart Rate Calculation
2. Sinus Rhythms and Sinus Node Dysfunction
3. Atrial Dysrhythmias
4. Junctional Rhythms
5. Ventricular Dysrhythmias
6. AV Blocks and Conduction Disorders
7. Pacemaker Rhythms and Artifact Recognition
8. Clinical Interventions and ACLS Correlation
,2|Page
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
Correct Answer: C. SA node
The sinoatrial (SA) node, located in the right atrium, is the heart's natural pacemaker. It
normally discharges at 60-100 beats per minute. The AV node delays impulses; Purkinje
fibers are the terminal conduction pathway.
Question 2: At what rate does the SA node normally fire in a resting adult?
A. 20-40 beats per minute
B. 40-60 beats per minute
C. 60-100 beats per minute
D. 100-150 beats per minute
Correct Answer: C. 60-100 beats per minute
The SA node is the primary pacemaker with an intrinsic firing rate of 60-100 bpm. The AV
junction has a backup rate of 40-60 bpm, and the Purkinje fibers have an intrinsic rate of 20-
40 bpm.
Question 3: Which component of the ECG represents ventricular depolarization?
A. P wave
B. PR interval
C. QRS complex
D. T wave
Correct Answer: C. QRS complex
The QRS complex represents the electrical impulse traveling through the ventricles, causing
them to contract. The P wave represents atrial depolarization, and the T wave represents
ventricular repolarization.
Question 4: On standard ECG paper, what is the standard speed?
A. 15 mm/second
B. 25 mm/second
, 3|Page
C. 50 mm/second
D. 100 mm/second
Correct Answer: B. 25 mm/second
The standard ECG paper speed is 25 mm per second. At this speed, each small box (1 mm)
represents 0.04 seconds, and each large box (5 mm) represents 0.20 seconds.
Question 5: On standard ECG paper, 1 small box (1 mm) represents how many seconds?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.50 seconds
Correct Answer: A. 0.04 seconds
At standard speed (25 mm/sec), each small box = 0.04 sec (40 ms). Each large box (5 small
boxes) = 0.20 sec. The PR interval is normally 0.12–0.20 sec (3–5 small boxes).
Question 6: A normal PR interval should measure:
A. 0.04–0.08 seconds
B. 0.08–0.12 seconds
C. 0.12–0.20 seconds
D. 0.20–0.30 seconds
Correct Answer: C. 0.12–0.20 seconds
The normal PR interval ranges from 0.12 to 0.20 seconds (3-5 small boxes). It represents the
time from the onset of atrial depolarization to the onset of ventricular depolarization.
Question 7: What does the horizontal axis on an ECG measure?
A. Voltage
B. Time
C. Amplitude
D. Resistance
Correct Answer: B. Time
The horizontal axis on ECG paper measures time. The vertical axis measures voltage
(amplitude).
