Relias Dysrhythmia Basic A Exam
Complete Practice Test – 100+
Questions
2025/2026 Edition
SECTION 1: ANATOMY, PHYSIOLOGY & ECG BASICS (Questions 1-25)
1. Which structure of the heart is known as the primary pacemaker?
A. AV node
B. Bundle of His
C. SA node
D. Purkinje fibers
Correct Answer💜💜: C. SA node
Rationale: The sinoatrial (SA) node normally initiates the electrical impulse at a
rate of 60–100 bpm due to its fastest inherent automaticity .
2. A normal resting heart rate for an adult is:
A. 40–60 bpm
B. 60–100 bpm
C. 100–120 bpm
D. 120–160 bpm
Correct Answer💜💜: B. 60–100 bpm
,Rationale: Sinus rhythm is defined by a ventricular rate between 60 and 100 beats
per minute in adults .
3. Which ECG wave represents atrial depolarization?
A. P wave
B. QRS complex
C. T wave
D. U wave
Correct Answer💜💜: A. P wave
Rationale: The P wave indicates the spread of an electrical impulse through the
atria, causing atrial contraction (depolarization) .
4. Ventricular depolarization is represented by which part of the ECG?
A. P wave
B. PR interval
C. QRS complex
D. ST segment
Correct Answer💜💜: C. QRS complex
Rationale: The QRS complex signifies the rapid depolarization of the right and left
ventricles .
5. The T wave on an ECG represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer💜💜: C. Ventricular repolarization
,Rationale: The T wave represents the electrical recovery (repolarization) of the
ventricles .
6. What is the normal duration of the PR interval?
A. 0.04–0.10 seconds
B. 0.12–0.20 seconds
C. 0.20–0.40 seconds
D. 0.40–0.60 seconds
Correct Answer💜💜: B. 0.12–0.20 seconds
Rationale: The PR interval measures the time from the start of atrial
depolarization to the start of ventricular depolarization; normally 0.12 to 0.20
seconds .
7. The normal duration of the QRS complex is:
A. Less than 0.04 seconds
B. Less than 0.12 seconds
C. Less than 0.20 seconds
D. Greater than 0.20 seconds
Correct Answer💜💜: B. Less than 0.12 seconds
Rationale: A narrow QRS complex ( <0.12 sec) indicates that the electrical impulse
traveled through the ventricles via the normal conduction pathway .
8. On the ECG graph paper, one small box represents how much time?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 1.00 second
, Correct Answer💜💜: A. 0.04 seconds
Rationale: Standard ECG paper runs at 25 mm/second. Each small (1 mm) box is
0.04 seconds .
9. One large box (5 small boxes) on the ECG paper represents:
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer💜💜: C. 0.20 seconds
Rationale: Since one small box is 0.04 sec, five small boxes (one large box) equal
0.20 seconds .
10. Which method is correct for calculating rate for a regular rhythm?
A. Count the number of QRS complexes in a 6-second strip and multiply by 10
B. Divide 1500 by the number of small boxes between R waves
C. Divide 300 by the number of large boxes between R waves
D. All of the above
Correct Answer💜💜: D. All of the above
Rationale: The 1500 method and 300 method are for regular rhythms; the 6-
second method works for irregular rhythms .
11. The 6-second strip method for rate calculation involves:
A. Counting the number of P waves and multiplying by 6
B. Counting the number of QRS complexes and multiplying by 10
C. Measuring the R-R interval in millimeters
D. Counting the number of large boxes between R waves
Complete Practice Test – 100+
Questions
2025/2026 Edition
SECTION 1: ANATOMY, PHYSIOLOGY & ECG BASICS (Questions 1-25)
1. Which structure of the heart is known as the primary pacemaker?
A. AV node
B. Bundle of His
C. SA node
D. Purkinje fibers
Correct Answer💜💜: C. SA node
Rationale: The sinoatrial (SA) node normally initiates the electrical impulse at a
rate of 60–100 bpm due to its fastest inherent automaticity .
2. A normal resting heart rate for an adult is:
A. 40–60 bpm
B. 60–100 bpm
C. 100–120 bpm
D. 120–160 bpm
Correct Answer💜💜: B. 60–100 bpm
,Rationale: Sinus rhythm is defined by a ventricular rate between 60 and 100 beats
per minute in adults .
3. Which ECG wave represents atrial depolarization?
A. P wave
B. QRS complex
C. T wave
D. U wave
Correct Answer💜💜: A. P wave
Rationale: The P wave indicates the spread of an electrical impulse through the
atria, causing atrial contraction (depolarization) .
4. Ventricular depolarization is represented by which part of the ECG?
A. P wave
B. PR interval
C. QRS complex
D. ST segment
Correct Answer💜💜: C. QRS complex
Rationale: The QRS complex signifies the rapid depolarization of the right and left
ventricles .
5. The T wave on an ECG represents:
A. Atrial depolarization
B. Ventricular depolarization
C. Ventricular repolarization
D. Atrial repolarization
Correct Answer💜💜: C. Ventricular repolarization
,Rationale: The T wave represents the electrical recovery (repolarization) of the
ventricles .
6. What is the normal duration of the PR interval?
A. 0.04–0.10 seconds
B. 0.12–0.20 seconds
C. 0.20–0.40 seconds
D. 0.40–0.60 seconds
Correct Answer💜💜: B. 0.12–0.20 seconds
Rationale: The PR interval measures the time from the start of atrial
depolarization to the start of ventricular depolarization; normally 0.12 to 0.20
seconds .
7. The normal duration of the QRS complex is:
A. Less than 0.04 seconds
B. Less than 0.12 seconds
C. Less than 0.20 seconds
D. Greater than 0.20 seconds
Correct Answer💜💜: B. Less than 0.12 seconds
Rationale: A narrow QRS complex ( <0.12 sec) indicates that the electrical impulse
traveled through the ventricles via the normal conduction pathway .
8. On the ECG graph paper, one small box represents how much time?
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 1.00 second
, Correct Answer💜💜: A. 0.04 seconds
Rationale: Standard ECG paper runs at 25 mm/second. Each small (1 mm) box is
0.04 seconds .
9. One large box (5 small boxes) on the ECG paper represents:
A. 0.04 seconds
B. 0.10 seconds
C. 0.20 seconds
D. 0.40 seconds
Correct Answer💜💜: C. 0.20 seconds
Rationale: Since one small box is 0.04 sec, five small boxes (one large box) equal
0.20 seconds .
10. Which method is correct for calculating rate for a regular rhythm?
A. Count the number of QRS complexes in a 6-second strip and multiply by 10
B. Divide 1500 by the number of small boxes between R waves
C. Divide 300 by the number of large boxes between R waves
D. All of the above
Correct Answer💜💜: D. All of the above
Rationale: The 1500 method and 300 method are for regular rhythms; the 6-
second method works for irregular rhythms .
11. The 6-second strip method for rate calculation involves:
A. Counting the number of P waves and multiplying by 6
B. Counting the number of QRS complexes and multiplying by 10
C. Measuring the R-R interval in millimeters
D. Counting the number of large boxes between R waves
